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Qatar Medical Journal - 1 - Extracorporeal Life Support Organisation of the South and West Asia Chapter 2017 Conference Proceedings, فبراير ٢٠١٧
1 - Extracorporeal Life Support Organisation of the South and West Asia Chapter 2017 Conference Proceedings, فبراير ٢٠١٧
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Qatar welcomes the Extracorporeal Life Support Organisation of the South and West Asia Chapter 2017 Conference
Extracorporeal Life Support (ECLS) is saving an increasing number of lives worldwide,1 so it is a great pleasure to welcome for the first time in Qatar the South and West Asia Chapter (SWAC) of the Extracorporeal Life Support Organisation (ELSO). The conference organizing and scientific committees have worked tirelessly under the leadership of Dr Ibrahim Fawzy Hassan (2017 Conference Chair) to make ELSO SWAC 2017 an enriching event that will help progress ECLS in the region. For this special occasion, the SWAC ELSO 2017 submission editorial team (AAH, AS, GA, CC, TM) is pleased to have been able to publish all accepted abstracts in this special issue of the Qatar Medical Journal (QMJ) as a legacy of everyone's efforts and commitment to contribute to saving lives. The vast majority of the abstracts are invited contributions from selected clinicians who are bringing specific knowledge and expertise to the conference and to the pre-conference workshops. The submissions received as part of the call for abstracts are presented at the end of this QMJ issue and been presented either as short oral or poster presentations during the conference. All submissions have been subjected to a rigorous peer review process involving a team of reviewers with a range of subject expertise and to whom we are grateful. Overall, this QMJ special issue represents the scientific contributions from over 150 authors from 17 countries.
The spread of the safe practice of ECLS, especially with regard to severe respiratory failure (SRF), relies on effective team training and education of the clinicians. To that effect, this year's theme is “Bringing ECMO Simulation to Life” and is directly reflected in the series of simulation-based pre-conference workshops which include:
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‐ Adult respiratory ECMO
‐ Adult cardiac ECMO
‐ Neonatal and pediatric ECMO
‐ Percutaneous cannulation ECMO
‐ ECMO transport
We hope that the experiences regarding simulation technology2–4 and educational approaches5 shared within the abstracts will benefit everyone. We believe that ECMO-specific simulation plays a vital role in safely implementing this crucial but complex lifesaving treatment modality in the medical community.6,7
The first successful clinical use of ECMO (Extracorporeal Membrane Oxygenation) was seen in the 1970s followed by encouraging results in clinical trials in neonatal population in the 1980s. ECMO became a standard of care for management of post-operative cardiac failure in major pediatric heart centers in the 1990s. The use of ECMO as a modality of care in adult ICU was initially faced with multiple challenges until H1N1 flu pandemic in 2008–2009 which, along with major improvement in devices, led to a rapid increase in its use for cases of acute respiratory distress syndrome (ARDS). Currently, ECMO is used for severe heart and lung failure in all ages.8
After being almost abandoned, veno-venous (VV) ECMO, commonly known as “respiratory” ECMO gained a new and strong legitimacy among ARDS therapies. Indeed, whether among neonatal, pediatric, or adult cases, the number of respiratory ECLS runs has increased over the last decade and has the best patient survival rate of all ECLS strategies.9 Every year, new centers start their program with the best aspirations of saving lives and share information about their journey.10–14 As VV ECMO is becoming the gold standard therapy as a bridge to many options (e.g. recovery, diagnosis, decision, transplant), it is nearly becoming unacceptable to die from an acute SRF. The abstracts presented in this conference show that teams use VV ECMO for increasingly diverse clinical indications such as pulmonary embolism (PE), septic shock, trauma, and HIV,15–20 far from the formerly accepted indications. The positive outcomes sometimes achieved are encouraging and support the idea of researching new ECMO applications as a rescue therapy.
Nurses are an integral part and essential to the VV ECMO management team. Daily nursing care of ECMO patients is an area of research for improving VV ECMO management.21 Finally, the historical imperative need to anticoagulate all patients on VV ECMO becomes actually nuanced and better assessed by many centers depending on the clinical situation if the risk of bleeding is high.20,22,23 This allows the possibility of initiating ECMO on patients who have a contraindication to anticoagulation.24 It seems VV ECMO continues to successfully shape its own future.
Another form of ECLS therapy is cardiac or veno-arterial (VA) ECMO for which indications are also diverse. Established indications include post-cardiotomy and as a bridge to recovery or to mechanical support. Provision of VA ECMO for cardiac arrest survivors and as part of cardio-pulmonary resuscitation (E-CPR) is gaining popularity worldwide.25 The results of this novel resuscitation strategy remain to be established. Enthusiasts advocate E-CPR for out-of-hospital cardiac arrest, while others provide E-CPR in the Emergency Department.26,27 Most probably, we will learn along the way how to better select patients and who are the most likely to benefit from E-CPR. Another huge area for development is ECMO in the cardiac catheterization laboratory.25,28,29 Interventional cardiology and minimally invasive cardiac procedures have revolutionized the care of cardiac patients. Initiation of VA ECMO prior to, during, or after PCI is likely to increase with more complex patients and higher expectations of the public. Cardiac ECMO management poses several challenges. Echocardiography is particularly useful, may reveal new or worsening pathology, and can help tailor management strategies.30 Distension of left ventricle during VA ECMO is problematic and needs special consideration.31 Another potential complication of VA ECMO is Harlequin syndrome.32
Although the VA mode still remains the primary mode of ECMO support in neonates, a steady rise in the use of the VV mode has been witnessed in the recent times.33–35 The physiological principles of management on ECMO are well established; however, improvement in ongoing care is attributed to the advanced research in the field of ECMO.8,36 Controversies and important questions still exist in certain aspects of care like best agent and tool to monitor anticoagulation,22 prognostication and long-term outcome,33 and modality to provide renal support therapy. Criteria for ECMO in neonates with congenital diaphragmatic hernia still remain an inexact science.37 Owing to significant improvements in neonatal clinical care and innovation of novel therapies for the primary diseases, ECMO is finding its way in previously unexplored indications and in clinical situations considered as absolute contraindication in the past. In 2008–2012, the ELSO registry documented that 178 patients with malignancy received ECLS, which equates to 1% and a doubling of utilization compared with that reported previously. This is attributable to the significant improvement in five-year survival (>80%) for childhood cancers.38
A particular aspect, underrepresented in the literature, research, and training, is mobile ECMO. ECMO patients represent the extreme of pathophysiology and moving them adds increased risk, and hence requires meticulous planning, competent personnel, checklists, and attention to details to ensure patient safety. ECMO is often located in specialized regional centers, thus necessitating moving patients.39,40 As yet, no consensus exists on optimal team composition, and specific roles vary considerably between centers. Whatever the configuration, the mobile ECMO team should have the necessary skills and competency to safely initiate, maintain, and trouble shoot any ECMO or clinical emergency.12 They should be self-sufficient and ensure adequate supply of all ECMO-specific equipment and have adequately trained personnel, appropriate vehicles, equipment, and medication.41,42 Incorporating the Ambulance Service professionals into the team to provide seamless team dynamics during retrieval may significantly contribute to improving mobile ECMO safety. Intensive or Critical Care Paramedics (CCPs) can play a logistics and safety role, allowing other members of the team to focus on their specific duties. CCPs are experienced in advanced airway, ventilation, and advanced cardiovascular life support (ACLS) skills, providing the team with additional skills in the event of an emergency.43 One of the key aspects in preventing patient safety issues and minimizing risks of harm during the transportation of an ECMO patient is to develop a well-prepared multiprofessional team. Mobile ECMO simulation can play a very important role in developing not only core skills but also enhance general team dynamics5,6 (Figure 1).Figure 1. ECMO team taking part in a truly interprofessional simulation-based training activity with the purpose-designed ICU ambulance and ECMO stretcher (picture courtesy of Hamad Medical Corporation).
Of increasingly recognized importance to improve the quality of care and improve patient outcome is the involvement of other allied healthcare professionals into the ECMO team such as physiotherapists and perfusionist.44,45 They complement the key role played by the critical care nursing staff who have acquired expert knowledge and skills and become ECMO nurse specialists who can integrate the operation of the ECMO machine, ventilatory requirements, and patient's medical management.21,46,47 They fulfill an increasing number of responsibilities in the multiprofessional team.
Each ECMO center needs to create their own program-specific indications, team structure and composition, and management strategies, including clear exit plan after taking into consideration the available resources, and ethical, religious, and cultural aspects of their specific environment.48 We hope that this new collection of articles and abstracts will contribute to the advancement of ECLS therapies worldwide and development of expert teams who safely acquire the required skills and knowledge using various simulation modalities.
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Building Qatar severe respiratory failure ECMO program
المؤلفون: Ibrahim Mohamed Fawzy Hassan and Loua Al ShaikhIntroduction: The aim of the program was to establish a severe respiratory failure (SRF) service with mobile extracorporeal membrane oxygenation (ECMO) retrieval capability throughout Qatar. This was achieved through the collaboration of various Hamad Medical Corporation (HMC) entities (critical care, cardiothoracic surgery, vascular surgery, and ambulance services). The service was commissioned by the Ministry of Public Health in October 2013 in response to the emerging MERS-Corona outbreak and its associated high mortality. After extensive team building and training, the service treated its first patient in June 2014. The key result has been an improvement in survival rate from 19 to 68%. The service is ranked among the best in the Extracorporeal Life Support Organization (ELSO) outcomes benchmark of worldwide SRF services. The provision of the highest quality care to patients with high predicted mortality has given a new hope in improving clinical outcomes and their reintegration into community. Background: In 2013, a novel virus (MERS Corona virus) was identified in Saudi Arabia, with subsequent cases in other gulf states including Qatar.1 The MERS virus was associated with rapid onset of severe respiratory and renal failure, resulting in a very high mortality rate (>50%) in the early days of the infection.2 The need to establish a SRF center with mobile ECMO retrieval capabilities was identified by the HMC senior leadership in order to anticipate and proactively deal with the situation. The program became a matter of utmost importance due to the inevitable social, political, and geographical factors, which united the people of the GCC. Strategically speaking, regulating the travel norms or bringing in a quarantine on travelers arriving from the countries affected by the MERS Corona virus were not a feasible alternative.3 Furthermore, the high mortality rate, failure of conventional ICU care, and the high cost of transporting and hospitalizing these patients in other countries with advanced respiratory support capability highlighted the need for the development of a severe respiratory failure and extracorporeal membrane oxygenation (SRF-ECMO) service program in Qatar. Evidence: The value of a SRF-ECMO service had previously been demonstrated during the international outbreak of H1N1 virus, when survival of patients with significant respiratory failure would have been left to chance or luck if no such advanced program had been in place. The SRF-ECMO services were achieving global survival rates of 60–70% in patients with otherwise very high mortality rates.4 Additionally, treatment of SRF in the SRF-ECMO Center decreased mortality rates.5 The vision of the leadership in promoting interdepartmental collaboration along with the support from the management at various levels was the highlight in the development of this program which now is recognized internationally for its clinical excellence and well known for its best practices, teaching, and mentorship programs. Program implementation and team training: The idea of a SRF-ECMO service in the State of Qatar had to be planned immaculately due to the fact that this was the first project of its kind in the country and there is always a sense of anticipation and enigma surrounding such a cutting-edge technology being made available with the help of the government itself. As a result of various fruitful deliberations, a steering committee was created which identified all the potential services that would be involved in the program along with the identification of the potential stakeholders in its successful implementation. The Guys and St Thomas (GSTT) Hospital team in London (UK) was identified as the potential partner for the implementation of the SRF-ECMO in Qatar and hence an official mission consisting of leaders from various services involved went on a field visit to get a firsthand experience about the program. Various discussions with the GSTT team took place in order to understand the processes and the actual difficulties they faced when they started their own SRF-ECMO service.
The clinical leaders realized that the only way this project could succeed – taking into consideration the relative inexperience of the team involved with regards to ECMO – was to provide hands-on experience to all HMC staff involved so they could become a fully functional and highly efficient team, which worked according to the best current evidence-based practices. The HMC senior leadership left no page unturned in the training of the team members, which is exemplified by the various international courses and workshops they were supported to attend to master the art of ECMO. Members of the team attended:
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■ ECMO simulation course at GSTT
■ Cadaveric ECMO course in Charité Hospital (Berlin)
■ Residential hands-on training in London
In addition, selected stakeholders spent a short period of time at GSTT to observe their service and obtain more technical information to effectively set up the program. This investment was highly fruitful in the sense that various members of the team which included physicians, nurses, perfusionists, respiratory therapists, pharmacists, physiotherapist, nutritionists, critical care paramedics, and educators were able to take part and bring the knowledge and skills back in Qatar for the benefit of a whole region.
The training was intended to provide each member with the whole repertoire of knowledge so as to help in the smooth gelling and functioning of the team, which could produce optimum results within the minimal timeframe and with the resources then available.
The physicians were provided with all the resources to master the relevant knowledge in quality and research, and were given the best training for cannulation. They were also provided with the knowledge of the anticipated problems that could arise during the procedure and during the retrieval and transport of ECMO patients. The most important part of the documentation and guidelines were mastered by the very skillful team that included consultants, specialists, and fellows from the MICU.
The nurses in the team, who form an integral part in the success of the procedure and process, were trained as ECMO specialist nurses with the responsibility of ensuring that all were functioning well with the help of checklists, protocols, and guidelines. They also have an important role in training other nurses in the MICU about the techniques and processes involved in this complex lifesaving procedure. They were also provided with the Sheikh Khalifa Medical City (SKMC, Abu Dhabi) nurses training program to further enhance their clinical skills.
The respiratory specialists in the team were given training in pre-ECMO management and positive end expiratory pressure (PEEP) optimization along with the other important procedures like positioning in ECMO, recruitment maneuvers, and ventilation in ECMO.
The perfusionists were given training in all the technical aspects of the circuit and its interaction with the patient throughout the various phases of ECMO.
The pharmacists were trained with all the potential drug interactions in the ECMO patient interface and were given the responsibility of reviewing all the protocols for the drugs used by the GSTT team.
The physiotherapists were given training in the positioning of the patient (which can be tricky especially when they are prone) and were given the all-important jobs of resuming mobilization and exercise training of the patients while still on ECMO. Further, they were given special training in chest physiotherapy in patients who were on ECMO, which can be very challenging, given the technology involved.
The nutritionists in the team were responsible for the total parenteral nutrition (TPN) and the interactions with the circuits. They further were given training in enteral feeding in ECMO, which reduces the complications and the morbidity in patients who undergo successful decannulation.
The Critical Care Paramedics play an essential role in the mobile retrieval capabilities of the program, including the road map plan for activation and deployment of the team. In our case, they had crucial input into the design of the ECMO and ambulance trolley.
The educator integrated all the knowledge and skills to maintain the competency of the team, from simple water drills all the way to advanced simulation-based competency assessment. Up-to-date cases: The first patient was admitted to the SRF-ECMO service in May 2014 with H1N1 pneumonia and successfully discharged from the hospital after 3 weeks of ECMO therapy. Since then, the SRF-ECMO service has treated 50 patients with a survival rate of 66% in total. Of these patients, 25% were trauma cases. Additionally, the SRF-ECMO service has also started its retrieval arm, moving patients from other hospitals in Qatar to the SRF-ECMO Center following cannulation and placing the patient on ECMO, 11 retrievals have been undertaken with one patient dying before transport. Additionally, two patients have been transferred with ECMO to the Heart Hospital for Cardiothoracic Surgery (severe PE and thoracic trauma with bronchial tear) and one patient has been successfully repatriated on ECMO to India using our own aeromedical ECMO transfer team. Summary: The Qatar SRF-ECMO program is one of the few programs worldwide that operates to the highest level and has been developed in less than 6 months. This has only been possible thanks to the enormous support of the leadership, dedication of the multidisciplinary team, and the partnership with an experienced center such as Guy's and St Thomas’ NHS Foundation Trust.
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Respiratory ECMO
المؤلفون: Ibrahim Fawzy HassanIntroduction: The H1N1 epidemic in 2009 caused a significant increase in the utilization of respiratory extracorporeal membrane oxygenation (ECMO) therapy for severe respiratory failure (SRF) patients who failed to improve following conventional ventilation therapy. Its use was linked to a high patient survival rate (more than 70%) reported from Australian and New Zealand1 as well as Canadian ECMO2 registries. It eventually led to the CESAR randomized controlled trial3 that clearly showed mortality benefits for adult patients with, potentially reversible, severe respiratory failure who were treated in ECMO centers. In that study, more than 63% of the referred patients survived and 75% of them received ECMO therapy, whereas in the conventional treatment arm, the survival rate was only 47%.
The significant change in the outcome, compared with old data, is related to several factors, such as advances in ECMO technologies, the use of veno-venous (VV) ECMO instead of veno-arterial (VA) ECMO, advances in the tubing and the membrane that are currently used, better understanding of lung and patient management during ECMO therapy, and early deployment of the rescue therapy.
In this review, we are going to discuss the physiology of oxygenation and the overall management strategy on ECMO during early course of active inflammation, all the way through to weaning during the healing phase of the lung injury. O2 is a perfusion-limited gas: This means that O2 depends not only on its ability to diffuse through the membrane, which is 25 times less than CO2, but also on perfusion capacity of the area being oxygenated. To explain that in a simple way, we will assume that O2 is a gas that cannot swim in the blood, and if it is left alone it will sink and cause free radical injury. It needs a carrier, such as the hemoglobin, and flow, which is the cardiac output or ECMO flow to push that carrier. If the transport capability of the blood is saturated, additional oxygen will be left out and will not be transported to the rest of the body. The perfusion limitation concept is very important to understand the shunt physiology. For example, if a patient with complete consolidation of both lungs has a cardiac output of 10 L/min and is on a 5 L/min ECMO flow, only 50% of the patient cardiac output is getting exposed to the gas exchange area and 50% is shunting through the diseased lung. When they mix together, 50% of the blood will be de-oxygenated, which will cause severe persistent hypoxemia. To solve this problem, we either recruit more lung units or decrease the overall patient cardiac output to decrease the intrapulmonary shunt. Adding more oxygen to either disease obstructed alveoli or the ECMO membrane will not solve the problem.4Carbon dioxide is a diffusion-limited gas: CO2 does not have the same problem as oxygen. It can ride on the hemoglobin, the albumin, and can also swim in the CO2–HCO3 buffer. The only limitation of CO2 is the flow of fresh air, whether it is minute ventilation or ECMO sweep gas flow, and this is related to the very low concentration of CO2 in room air and its ability to diffuse through the membrane 25 times more than oxygen. CO2 clearance on ECMO can be controlled by increasing the sweep gas flow. The difference between membrane lung and artificial membrane: Despite the significant advances in technologies, the artificial lung development remains in its infancy and far from complete for various reasons:
The total surface area of a normal human lung is about 70 m2, whereas the best artificial lung membrane has a maximum equivalent of 4 m2. The thickness of a normal human lung is about 0.5 μm, whereas an artificial membrane is 300 times thicker, with an average thickness of 150 μm. Important factors affecting the diffusion and the uptake of oxygen are:
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A– The red blood cell (RBC) transient time, which is 0.4–1 second in a normal lung and much shorter in the artificial membrane lung.
B– The way that RBC cross the normal capillary is almost one cell at the time, compared with the membrane lung capillary where red blood cells cross in clusters. For all the above reasons, the maximum oxygen transfer capability of the artificial membrane (400–600 mL O2/min) is much less than the normal human lung (>2000 mL O2/min).
The focuses in this phase are:
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1– Maximizing ECMO flow as the patient depends almost 100% on the ECMO for oxygenation to maximize O2 delivery;
2– Resting the lung and switching the focus of ventilation from enhancing lung recruitment to preventing the de-recruitment of whatever is left of the lung tissue.
3– Full patient rest to decrease O2 consumption, which will also decrease the cardiac output appropriately and hence decrease intra-pulmonary shunt. This is usually achieved by sedation, paralysis, temperature control, and sometimes adding beta blockade.
4– Optimizing the native lung function by early diagnosis and treatment of the underlying condition, negative fluid balance if tolerated by the ECMO flow and secretion mobilization usually with bronchoscopies rather than just physiotherapy, as the patient is usually deeply sedated.
The focuses in this phase are:
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1– Starting to wean ECMO flow and sweep gas flow to allow the stimulation of the native lung.
2– Focusing on lung recruitment and diaphragmatic muscle dysfunction prevention using various ventilation modes such as neutrally adjusted ventilatory assist (NAVA), pressure support ventilation (PSV), and others, and also early extubation on ECMO is warranted.
3– Weaning of all sedatives and paralytics, management of delirium, and most importantly, aggressive physiotherapy on ECMO.
4– Continuing to optimize native lung function with aggressive chest physiotherapy; however, fluid strategy could be liberal at this stage to facilitate sedation weaning without affecting the ECMO flow.
Later in the course, as discussed earlier, the goal is to wean sedation and paralysis, and to ensure spontaneous ventilation to decrease the risk of ventilator-induced diaphragmatic muscle dysfunction. During this period, the access insufficiency occurrence might increase and controlling the access will be by fluid boluses in the expense of weaning the sedatives and paralytics. Summary: The use of respiratory ECMO has been continuously increasing for SRF patients globally. Despite significant advances in technologies, the artificial membrane lung still has significant limitations in comparison to the normal human lung. Given that oxygen is a perfusion-limited gas, maximizing the ECMO flow to match the patient's cardiac output is essential to overcome the membrane limitation.
The management strategy during an ECMO run is different from the early inflammatory course to the late recovery course, not only on the diseased lung, but also on the entire body system, and this has to be considered during therapy on VV ECMO. Fluid management in particular has to be carefully evaluated using different tools such as ECHO-guided assessment for volume responsiveness.
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The journey of pediatric ECMO
المؤلفون: Tejas Mehta, Ahmed Sallehuddin and Jiju JohnIntroduction: Extracorporeal membrane oxygenation (ECMO) is an adaptation of conventional cardiopulmonary bypass techniques used for long-term support of respiratory and/or cardiac function. It provides physiologic cardiopulmonary support for patients with acute, reversible cardiac or respiratory failure. The term “extracorporeal life support” (ECLS) was proposed to describe prolonged but temporary (1–30 days) support of heart or lung function using mechanical devices. Technically, ECMO terminology is used for modalities that provide pulmonary support system involving oxygenation and carbon dioxide removal, and ECLS is used for both cardiac and pulmonary support systems, but these terminologies are still used interchangeably.1,2
Over the past 30 years, due to significant advances in the understanding of physiology, improvement in clinical care, innovation of novel therapies for primary diseases, and technological advances, there have been major changes in indications, cannulation, duration of treatment, and outcome for the children being treated with ECMO. Patient selection remains key to a successful outcome since ECMO is a supportive therapy utilized while waiting for a reversible condition to resolve through other treatment strategies.
According to the registry report of the Extracorporeal Life Support Organization (ELSO), over 78,000 cases have been reported until July 2016. Of these cases, 29,153 are newborn infants with respiratory failure, 74% of which survived to hospital discharge; 18,153 of them are patients managed with ECMO for severe respiratory failure in the pediatric (7,552) and adult (10,601) age groups with survival to a hospital discharge rate of 58% in each group. All other cases relate to cardiac support in neonates, children, and adults with rates of survival to hospital discharge ranging between 40 and 50%.3History: Bubble oxygenators, used in early cardiopulmonary bypass systems, were characterized by a direct interface between blood and gas. However, significant hemolysis caused by these oxygenators limited prolonged exposure.4 Long-term support was made possible by the development and introduction of membrane oxygenators, which physically separated the blood and gas phases and thus minimized the problem of hemolysis.5 In 1972, the first successful use of prolonged cardiopulmonary bypass was reported by J. Donald Hill.6 The patient was supported for 3 days with venoarterial extracorporeal bypass support for a ruptured aorta following a motorcycle accident. Neonatal evidence: In 1976, Bartlett et al.1 reported on baby Esperanza, the first successful neonatal ECMO survivor. She was supported for 3 days on ECMO for respiratory failure secondary to meconium aspiration. Dr Bartlett led the first prospective randomized, controlled trial (RCT) that evaluated neonatal respiratory ECMO against conventional management, which was conducted at the University of Michigan in 1985.7 This study was published to demonstrate the benefit of ECMO by comparing cases in which all patients supported with ECMO survived, while conventionally treated patients died. The study faced much criticism. This led to a second larger study by Dr Pearl O'Rourke at Boston Children's Hospital in 1989. Of 10 patients who were conventionally supported, only 6 survived, whereas of 29 patients who were supported with ECMO, 28 survived.8 In 1996, the UK Collaborative ECMO Trial Group published a 55-center conventionally designed RCT. Neonates with PPHN were randomized to either stay in their referral center for standard therapy or be transferred to a regional ECMO center. Survival was found to be higher in those receiving ECMO than in those who did not receive it (60% vs. 40%). Follow-up at 1 year showed a significantly lower death rate or severe disability in the ECMO group.9 A Cochrane review (2008) by Mugford and colleagues evaluated four trials by comparing ECMO and conventional management for neonatal respiratory failure. Increased survival to hospital discharge with ECMO support was demonstrated by all the four studies when compared with conventional therapeutic strategies. Of a total of 244 infants, 77% survived in the ECMO group whereas only 44% survived in the conventionally managed group.10 Bartlett et al.11 attributed the success of ECMO in newborns to the fact that the lungs require only a short time for recovery in neonates with respiratory failure. The data from the prospective randomized controlled trial from the UK showed rigorous evidence of the cost-effectiveness of neonatal ECMO during childhood.12Pediatric evidence: In the 1980s, the benefit of ECMO for pediatric patients was subject to discussion in the medical community.13,14 Concerns were raised about the application of the new, expensive, and potentially dangerous technology in children in whom pulmonary injury could be due to widely unknown mechanisms. To gain further acceptance of ECMO in children, performance of a RCT was considered mandatory. However, this approach was postponed due to ethical considerations. In 1996, Green et al.15 published the results of a retrospective multicenter cohort analysis in 331 pediatric patients. Evaluation of factors associated with survival was done with a multivariate logistic regression analysis. ECMO was found to be associated with a reduction in mortality. An additional matched-pairs analysis revealed 74% survival in the ECMO group (n = 29) and 53% in the non-ECMO group (n = 53) (P < 0.01).
In the review of ECMO utilization in neonatal and pediatric respiratory failure between 2002 and 2012, survival was found to be consistent at 57%, despite increasing comorbidities. However, for patients without comorbidities, survival increased from 57 to 72% over the study period. Children supported with ECMO for status asthmaticus, aspiration pneumonia, and respiratory syncytial virus pneumonia had higher survival rates (between 70 and 83%). Poor prognostic indicators included patient age between 10 and 18 years, hepatic or renal failure, evidence of immune dysfunction, and diagnosis of fungal pneumonia, pertussis, or ARDS secondary to sepsis.16
For children with severe cardiac failure, ECMO is used to provide temporary circulatory support for patients with potentially reversible disease or as a bridge to decision, either device or transplant. In a prospective multicenter study involving 17 pediatric cardiac centers, children who underwent implantation of the pediatric Ventricular Assist Device (VAD) as a bridge to transplantation were compared with a historical control group of children who received circulatory support with ECMO. Significantly higher survival rates were associated with VAD when compared with ECMO (88–92% vs. 75–67%). However, VAD use is not without complications, with the most common ones being bleeding, infection, stroke, and hypertension. This makes balancing when (or if) to institute the support even more challenging.17
The way forward: With the success of less-invasive respiratory support measures, the demographics of pediatric ECMO patients will continue to change with increasing numbers of support for patients with cardiac dysfunction and less for those with respiratory failure.18–20 Improving results will encompass highly complex patients, and those with single-ventricle physiology will not be denied support and, in fact, will contribute a large percentage of ECMO patients.21 Smaller and more efficient cannulas22 are increasingly available for effective and rapid peripheral cannulation,23,24 and can potentially trigger an upsurge in ECMO-CPR in children.18,25
Remarkable advancement in pumps, oxygenators, and heparin coating of artificial surfaces has resulted in higher biocompatibility and lower rates of complications. Furthermore, improvements in monitoring anti-coagulation and control of bleeding24 through the development of rapid and accurate point-of-care devices will make ECMO safer for children. A key factor leading to complications in small bodies is the exposure to large volumes of fluids. Experimental miniature pumps that diminish priming volumes and circumvent hemodilution could eventually provide a solution.26
Upcoming generation of centrifugal pumps using magnetic levitation appears to improve end-organ recovery where supported patients show a trend toward better hospital survival and significantly higher late survival.27 It is essential that future ECMO devices should make support much simpler, safer, and to a great extent automatic, while decreasing the need for anticoagulation. ICU nurses rather than ECMO specialists should manage the system, reducing the cost while maintaining ease and safety.20,28 Continued education with the help of regulated training of all participants and use of simulation should be part of in-service activities within each institution committed to advance the service.
Pediatric cardiac transplantation will hopefully be available in the Gulf area, but is not currently a treatment strategy. Technological advances in implantable centrifugal and axial flow pumps have yet to be miniaturized for suitable use in infants and neonates, which is proven difficult until now.29 On the flip side, significant advances to provide successful ECMO support for weeks or months have been achieved.19 Reduction in sedative use and keeping patients more awake,19 together with improvement in ventilator support to the point of extubation, could potentially lead to ambulatory ECMO. It could therefore potentially evolve into a definitive component of mechanical heart failure therapy in this region.
Data and registry need to be widespread and garnered from multicenter experiences to provide understanding to the quality of life after ECMO in children. It could also guide us to develop criteria for the use of ECMO as a resuscitative tool in cardiac arrest,19 and provide an answer to the controversial relationship between volume and outcome, and whether service regionalization would deliver the promise of improved results. Conclusion: ECMO is used as a standard of care for neonates and children with severe cardiac and pulmonary dysfunction refractory to conventional management. A lot of wisdom has been gained through research and experience with a resultant change in practice in the field of neonatal and pediatric ECMO over the past three decades with many promising advances awaiting support with robust evidence.
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ECMO retrieval: A case for Critical Care Paramedic integration into the team
المؤلفون: Craig B. CampbellIntroduction: The provision of an effective extracorporeal membrane oxygenation (ECMO) service requires a dedicated unit with sufficient caseload and access to specialised resources.1 Moving unstable patients, with refractory respiratory failure on conventional mechanical ventilation, to the specialised centre for ECMO poses great risk to the patient.1,2 Therefore, there is a need to have mobile ECMO capabilities with specialised retrieval teams, capable of initiating ECMO in the referral hospital and safely transporting the patient to the ECMO centre. Transport of patients on ECMO has been demonstrated to be safe, if undertaken by well-trained teams2–7 providing seamless care.8 However, most studies pay little attention to the role of the ambulance service within the ECMO team.
The ideal configuration of the team has yet to be demonstrated, with different regions using different models.2 The ELSO guidelines recommend, beside the ECMO specialist and cannulating physician, a transport nurse or respiratory therapist to provide ongoing critical care to the patient.9 This recommendation presupposes a model where nurses are routinely involved in interfacility transport of patients. It further ignores the role of ambulance service staff, who potentially play an integral role in the movement of the patient. This model is by no means universal, and certainly not the case in Qatar, hence the decision to include Critical Care Paramedics (CCP) as an integral part of the Qatar ECMO team, in service of safe ECMO patient transport. Multidisciplinary team dynamics in patient transport: As with the management of the ECMO patient within the ICU unit, the success of each retrieval and transport depends as much on team dynamics as on the technical skills of the individual specialities represented in the team.10
Due to the specialised nature of ECMO, the retrieval team cannot rely on the referring hospital having all the required equipment. Thus, the team needs to be self-sufficient and the team members interdependent on each other. Prior to activation of the team, each speciality is responsible for ensuring their specific retrieval equipment has been checked and sealed in readiness for the next retrieval. As part of this process, the ECMO retrieval team developed a set of checklists for each of the equipment sets (checked weekly) and a master retrieval checklist to be used by the CCP on activation of the team. The use of checklists ensures that all equipment boxes, required for cannulation and patient care, are loaded into the transport vehicles.9
The design of the retrieval service vehicle and High Acuity Patient Transport Trolley has factored in the principle of redundancy, realising that the patient on ECMO has limited physiological reserve if equipment, power or oxygen supply failure should occur. The close working relationship between the ECMO director and the Ambulance Service staff has helped develop a platform and system that provides redundancy and limits the requirement for the ECMO team to have to carry additional backup equipment.
Once at the referring hospital, each member of the team has preassigned roles. The ECMO physician takes lead on assessment of the patient, deciding on the eligibility for ECMO. The decision to initiate ECMO requires consent from the family to begin. During that time, the rest of the team begin the process of identifying additional resources within the hospital. The ECMO specialist nurse begins assessing the needs of the patient prior to movement. Once consent is obtained, the team can begin the process of preparing the patient for transfer to theatre (unless the decision has been made to cannulate in the ICU) and to prepare the operating theatre for cannulation. Delegating the role of patient safety and logistics to the CCP frees up the need for the lead physician to multitask, thus being able to concentrate on the task of patient assessment, reducing the risk of error and co-ordinating the requirements for cannulation of the patient at the receiving hospital. The CCP also plays a support role for the ECMO nurse specialist in preparing the patient for transfer to the theatre (infusions, monitoring and ventilation), and becomes lead for the safe movement of the patient from the unit to the theatre, and later to the ambulance. Each step in the patient preparation and movement is confirmed as per the safety checklist to ensure nothing is missed, and the risk of accidental dislodgment of invasive lines or ET tube is minimised. Having a dedicated safety person allows other team members to concentrate on their primary task. Background:Building the Ambulance Service–Medical Intensive Care Unit relationship: Following the outbreak of MERS coronavirus, the leadership of HMC made a decision to develop a severe respiratory failure (SRF) service, including the implementation of an ECMO programme, as none existed in the country or the region. This service would be based at Hamad General Hospital in Doha. A centralised model of care would be used, thus requiring the establishment of an ECMO retrieval service.
The project development was tasked to the MICU Director, who also held the Deputy Medical Directorship of the Ambulance Service. This relationship had previously led to the Ambulance Service and the Medical Intensive Care Unit co-developing a multidisciplinary, simulation-based training programme in preparation for the launching of a High-Acuity Adult Retrieval Programme. This model paired MICU intensivists with Critical Care and Ambulance Paramedics on a purpose-built Mobile Intensive Care Ambulance, with the CCP as team leader. Based on the success of this programme, it was decided to include a small group of experienced CCPs in the ECMO training programme, which was initiated in November 2013. The envisaged role of the CCPs was to undertake the logistic lead and patient and team safety role on ECMO retrieval development.
As part of the initial training programme, two of the CCPs were included in the team that were sent for training with an established ECMO service in the UK. Their role was to get insight into the logistical requirements and evolution of ECMO retrieval and then become the project leads for the development of the Ambulance Service's capacity to support a seamless ECMO retrieval service. The ECMO retrieval team: In Qatar, the ECMO retrieval team is made up of either two ECMO specialists or an ECMO specialist and a MICU consultant, with an ECMO specialist nurse, perfusionist and respiratory therapist. In addition, the team has a CCP as an integral member of the team, with a central role in logistics and safety. The CCP helps link the decision-making and execution of patient movement and transport to any additional resources within the Ambulance Service that may be required and adds additional clinical capacity to the retrieval team.
In many countries, Critical Care or Intensive Care Paramedics play a central role in the interfacility transport of critically ill or injured patients, either by ground or air ambulance. Advanced Life Support Paramedics receive additional training in Critical Care Transport and Aeromedical Medicine, and then, work in multidisciplinary teams geared to the safe transport of high acuity patients, either by ground or by air. These Critical Care Teams may be composed of two CCPs, or a CCP working with a Critical Care Nurse or Physician.
CCPs develop their skills of leadership, required for working in high-stress environments, through their training and through experience working in complex and austere clinical environments. In many of the countries mentioned above, paramedics are required to gain experience in the emergency setting, before being permitted to transfer into Critical Care Transport teams. This model ensures that the CCP/ICP is not only competent in Advanced Life Support skills but has had time to master the complexity of assessing and managing critical patients, patient advocacy and professional engagement with other healthcare professionals.
Qatar recruits its CCPs from Australia, Canada, New Zealand, USA and South Africa. All these countries have established Critical Care Transport programmes through tertiary-based paramedic education (Associate Degrees or Degrees). CCPs, within the Ambulance Service in Qatar, are able to provide advanced airway interventions (rapid sequence induction and intubation), use multimodal mechanical ventilation and provide advanced cardiovascular life support – including infusion devices, inotropes, external pacing and mechanical chest compression devices. In addition, the group of CCPs selected to be part of the ECMO programme all had more than 10 years of clinical experience and were trained and experienced in aeromedical work.
Being familiar with the equipment and systems of the Ambulance Service, the competencies of interfacility patient transport and having been trained with the MICU multidisciplinary team in the process of ECMO, allowed them a unique ability to take on a lead role in the logistics process and patient safety roles and provide an additional resource for the provision of airway care, ventilation or advanced cardiac life support.
From late 2014 to date, the Qatar ECMO team have undertaken 13 retrievals, including one international transport from Qatar to India, without any adverse incidents. The strong relationship between the ECMO team and the Ambulance Service has facilitated the development of a safe and effective retrieval service. Future plans to include the initiation of ECMO transport simulations to ensure maintenance of skills and develop team dynamics with new staff being added to the Service.
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ECMO in trauma patients: Future may not be bleak after all!
المؤلفون: Ali Ait Hssain and Tasleem Mohamed RazaIn the USA, trauma represents the leading cause of death between the ages of 1 and 46 years and contributed to 192,000 deaths in 2014.1 Major trauma is also responsible for significant disabilities and increased hospital length of stay (LOS), and represents a huge financial burden. Acute respiratory failure (ARF) is multifactorial in trauma patients with diverse underlying pathophysiological mechanisms. In a blunt thoracic injury, all the chest compartments can be affected and are directly responsible for mortality of 20–25%.2 Two main mechanisms contribute to pulmonary injury; the first mechanism is a direct trauma leading to contusion, intra-alveolar hemorrhage, and aspiration pneumonia. Some of the mechanical injuries to the chest (pneumothorax, hemothorax, airways injury) are reversible by various interventions (pleural drains, surgical airway repair, etc.). The second mechanism is an indirect immunological lung injury, which may result from extrapulmonary trauma and/or the required management of trauma patients (massive transfusion, fluid overload, ventilator lung induced injury, etc.) leading to acute respiratory distress syndrome (ARDS). Extracorporeal membrane oxygenation (ECMO) is an attractive therapy in ARF. In 1972, the first successful use of ECMO was in a 24-year-old polytrauma patient who developed a “shock lung syndrome”.3 However, subsequent results in the next two to three decades were disappointing. The H1N1 influenza epidemic with a high number of young patients with severe respiratory failure led to resurgence of ECMO use. ECMO has been successfully used in severe ARDS secondary to the influenza A (H1N1) epidemic in 2009 with acceptable outcomes. A large multicenter trial (CESAR trial) in the UK showed that referral and transfer of patients to severe respiratory failure centers with ECMO capabilities reduced mortality in severe ARDS patients.4 Despite these encouraging results and use of ECMO worldwide for severe ARDS, use of ECMO in trauma patient is poorly studied. Severe ARF requiring mechanical ventilation (MV) in trauma patients is associated with high mortality and increased hospital LOS. In patients with severe impaired gas exchange despite optimized MV, ECMO is proposed to avoid injurious lung ventilation. It is prudent to start ECMO at an earlier stage to avoid irreversible MV-induced pulmonary injury in these cases. In severe thoracic trauma cases requiring lung resection or progressive lung fibrosis with severely limited reserve, ECMO may prove to be the main therapy as a bridge to lung transplant. The heterogeneity and complexity of trauma patients make ECMO use challenging in trauma cases with uncertain benefit/risk balance and multidisciplinary decision-making becomes extremely important on a case-by-case basis. Among trauma patients with ARF, those with a traumatic brain injury represent a specific group as their prognosis is mainly dependent on neurological recovery. These patients may require earlier ECMO support compared with non-brain-injured patients, to prevent secondary neurological injury from severe hypoxemia, hypercapnic acidosis, and worsening cerebral edema from fluid overload. Indeed, the combination of gas exchange alteration from respiratory failure and intracerebral pathology leads to a difficult challenge in ventilatory management of these patients. The usual dilemma of lung-protective versus neuroprotective ventilation creates contradictory goals. A high PEEP strategy, permissive hypercapnia, and permissive hypoxemia are well-accepted strategies for ARDS management, but may lead to secondary neurological insult in brain-injured patients. Munoz-Bendix and colleagues showed in their study that intracerebral pressure can be decreased by the PaCO2 control with ECMO support in trauma patients, which is a major goal of neuroprotective ventilation in these patients.5 ECMO in brain-injured patient is an attractive option as it allows the combination of neuroprotective and lung-protective ventilator strategies at the same time. The goal of ECMO is to support the patients who have good functional prognosis from their neurological injury. Unfortunately, this prognostication is not easy in brain-injured patients at the time when they are in need of ECMO. Better prognostic predictors in brain-injured patients may help the healthcare teams to improve the selection of patients who will benefit from ECMO.
ECMO use is limited in trauma patients, particularly those with traumatic brain injury, complicated pelvic fractures, or major vascular injuries in view of fear of serious bleeding during systemic anticoagulation. However, with improved ECMO circuit technology (newer pump systems, reduced circuit area, newer biocompatible circuit material, heparin coating etc.), and a relatively high blood flow during veno-venous (VV) ECMO, thrombotic complications during heparin-free ECMO runs are relatively uncommon. In the literature, there are many reports of prolonged heparin-free ECMO use in patients with trauma as well as other pathologies with high risk of bleeding complications with excellent outcomes and no serious thrombotic complications.6–9 Recently, a systematic review of the literature with an aggregated total of 215 trauma patients showed an overall survival to discharge ranging from 50 to 79%;10 however, this work suffered from various limitations. All studies included were retrospective and included a maximum of five patients per year per center. Most of the studies with a high number of patients were performed over many years making definitive conclusions difficult to formulate as the ECMO management and techniques and ICU approaches have evolved over the years. An interesting cohort study using data from two American centers compared 76 trauma patients on MV and 26 who required VV extracorporeal life support (ECLS).11 There were no differences between the two groups regarding ventilator days, intensive care unit LOS, and hospital LOS. However, when ECLS patients were severity matched to patients on MV, a better survival was demonstrated in the ECLS group. These are very encouraging results, but there were multiple limitations, and lot of questions remained unanswered. Further studies are needed to define the appropriate time to initiate ECMO, proper patient selection, and outcome data beyond survival to hospital discharge, including functional and psychosocial outcomes, particularly in brain-injured patients. The holy grail of ECMO use in trauma patients is the optimal timing to initiate this therapy. ECMO is a complex treatment modality, which involves a multiprofessional team of clinicians, and financial and physical resources for its optimal implementation. The use of ECMO in inappropriate patient at an inappropriate time may lead to poor outcomes with wastage of precious healthcare resources. Unfortunately, several large ECMO centers do not have a level 3 trauma center and, at the same time, multiple trauma centers do not have any ECMO service. Therefore, studies from centers with combined trauma and ECMO services are really needed to demonstrate their complementary positive impact on the care of trauma patients. Trauma patients should be considered as a genuine group to benefit from ECMO support. Beside the encouragement of centers to publish their individual experiences, a multidisciplinary task force under the aegis of ELSO may be a reasonable approach to conduct studies to answer the unresolved questions of ECMO use in trauma patients. A reasonable first phase towards this goal would be to create a specific registry for interested centers with experience in trauma care as well as ECMO capabilities. The management of these patients is complex and needs a multidisciplinary team approach with experience of trauma teams as well as intensivists and an ECMO team with a reasonable patient volume. The specific pathways created by collaboration of ECMO specialists, perfusionists, intensivists, emergency room physicians, trauma surgeons, and interventional radiologists will lead to improved patient care as well as valuable data to optimize the care of these patients in the future. The time has come not to deny the lifesaving ECMO therapy to trauma patient based on our perceived notions and prejudices. Indeed, the decision to start ECMO in trauma patients is not easy and straightforward and needs input from multidisciplinary team members but should be considered for each patient on an individual basis and may lead to very satisfying outcome in these mostly young patients. The need for more data and more outcome-based well-designed studies are needed to better define the role of ECMO in the care of trauma patients. The ECMO community should work in harmony to achieve this goal. The future of ECMO in trauma patients may prove to be bright after all.
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Can simulation improve ECMO care?
المؤلفون: Ahmed Labib and Guillaume Alinier“Bringing ECMO simulation to life”: The main theme of the 4th Annual Conference of the Extracorporeal Life Support Organisation – South and West Asia Chapter (ELSO-SWAC), “Bringing ECMO Simulation to Life”, is meant to emphasise the growing role of simulation in healthcare and medical education at large and in the highly specialised and complex field of extracorporeal life support (ECLS), and in particular for extracorporeal membrane oxygenation (ECMO). Application of ECMO simulation to improve team response to ECMO emergencies was first described in 2006.1 In the last decade, several authors have described the development, utility, and advantages of simulation-based training for ECMO. In this editorial, we will discuss the role of and evidence supporting the use of simulation-based education in ECMO. ECMO is a complex intervention: The first point to consider when it comes to ECMO is the complexity, time critical, and inter-disciplinary nature of the intervention. Typically, ECMO is considered for the most sick and physiologically deranged patient, sometimes as a last resort rescue measure. Time pressure, the patient critical condition, the potential rapid deterioration, and the uncertainty interact within the critical care environment to make decision-making, planning, and execution quite challenging for the less experienced members of the clinical team. This relates to the domains of team and crisis resource management in which there is a complex interplay of human and environmental factors involved.2 Appropriate training programmes of the required technical and non-technical skills for ECMO are lacking.3,4 In addition, ECMO is relatively new to many centres and/or countries, and this novelty brings with it a general lack of experience regarding such therapy and the fear of the unknown. Simulation can help relieve staff anxiety and introduce ECMO in a safe, less intimidating learning environment.3,4 Ideally, all aspects of ECMO patient care can be progressively introduced to the staff being trained through the use of various simulation modalities to promote better understanding and deep learning regarding the initiation of an ECMO run and ongoing ECMO patient care. Simulation can expedite preparedness for crisis: On 11 June 2009, the World Health Organisation (WHO) declared a global H1N1 pandemic only two months after the influenza outbreak in Mexico and USA. This allowed very little time for governments and organisations to prepare.4 A 2010 European taskforce for the intensive care unit (ICU) triage of influenza epidemic or mass disaster recommended commencing training of clinicians as early as possible with demonstration followed by practice under supervision.5 In line with these recommendations, a 3-day ECMO-based simulation training was established to provide a large number of clinicians with the technical, behavioural, and cognitive ECMO skills in anticipation of the H1N1 pandemic. The programme enabled some ICUs with no previous ECMO experience to care for patients on ECMO.4 Although it was probably the product of an expedited process of rapidly setting up a custom simulation programme, as opposed to adopting a more structured approach involving step-by-step development and validation through piloting,6 the anticipated outcome was still deemed beneficial to justify the rapid process. The European Taskforce's recommendation demonstrated the importance given to this educational approach in such a critical time as clinicians had to commit to 3 days of training to master life-saving skills and it was widely rolled out. What can ECMO simulation provide?: Traditional ECMO training and education focused on didactic lectures, water drills, and animal laboratory.7 This mostly passive learning approach is suboptimum for adult learning as adults tend to prefer developing knowledge and understanding using problem-solving, as it encourages active leaning, sharing of knowledge, and acquisition of experience.8 It calls upon “learners” to develop and use critical thinking skills, not only during the simulation-based experience, but also during the “review” phase, which corresponds to the debriefing of the simulation. This phase is usually in the form of a facilitated discussion, which helps learners further explore the event they partook in, clarify doubts, and develop their knowledge.9 It is not always without difficulty, but it is a crucial learning phase to understand the thought process behind learners' actions and it allows to deepen their learning.10
ECMO is a unique patient management and therapeutic strategy that requires a diverse set of technical, practical, cognitive, as well as behavioural and other non-technical skills. Initiation and maintenance of ECMO requires ongoing interprofessional interactions, which may sometimes occur in high-intensity situations such as a circuit emergency, which usually requires a coordinated and synchronised response from the various team members. Akin to high-risk industries, poor communication, inadequate leadership, and a dysfunctional team can cause significant harm.11 The remedy adopted by high-risk industries, such as aviation, military, and the nuclear power plants, is regular simulation-based training for the employees, even if incidents are relatively rare, to ensure adequate readiness in the event of a potential crisis.12 The work by Brum et al.3 shows that a one-day multi-professional ECMO simulation course significantly improved staff confidence of ECMO management and enhanced behavioural skills. In another report, ECMO simulation improved thoracic surgery residents' skills in the management of post-cardiotomy ECMO crisis.13 Management of patients on ECMO mandates high level of communication skills and team work, and rapid decision-making and actions. Simulation-based ECMO training provides an ideal platform to develop and maintain such skills. It enhances team response to crisis and permits rehearsal of less common and atypical life-threatening emergencies.3,11 Simulation allows practice and acquisition of procedural skills in a safe environment,11 and these can be initially practised in isolation and individually, prior to being embedded into more complex scenarios tackled as part of a multiprofessional team. In addition, team building, decision sharing, and execution are improved via simulation-based ECMO training, which enhances patient safety and minimises errors in response to an ECMO crisis.3,11 The level of complexity and fidelity or realism adopted needs to match the intended types of learning objective and the level of experience of the participants.14 Beyond learners' educational and experiential benefits, simulation presents great opportunities with regard to systems' testing, environment orientation, as well as protocols and guidelines development. An application of particular interest is “in-situ” simulation, which engages the clinical team in their actual work environment,15 and hence with their own equipment with which they should already be familiar. Running in-situ simulations in particular is very useful to test the implementation of new services and identify potential risks and actual omissions of critical safety components.16,17 Putting clinical teams in various simulated normal and emergency situations within their own context allows for observation of their actions and challenges they face in relation to the procedure, equipment availability or familiarity, or physical environment configuration. The immediate next phase is to engage them in a debriefing that will help identify potential as well as actual system or environmental issues, and assist in developing appropriate solutions. Organising in-situ simulation can however be challenging, especially in an operational clinical environment where real patients who might be critically ill are also present.18 In the case of ECMO patient care-related in-situ simulation, it is the ideal setting to train a team to respond to a patient or circuit emergency, as it will test their ability to act appropriately and test the availability of the resources required to deal with an emergency circuit change or pump failure for example. A facility that has limited regular exposure to ECMO patients should be recommended to impose more regular in-situ simulations to ensure the clinical team and equipment are always ready to deal with any aspect of ECMO, right from the cannulation phase (wherever it may take place) and ability to bring together all required resources, performing an emergency circuit change, right through to weaning off a patient from ECMO. Conclusion: There is a universal growing interest in various aspects and applications of simulation-based training. Simulation for the initiation and maintenance of ECMO provides several advantages over traditional passive learning approaches. ECMO simulation improves technical skills such as cannulation as well as non-technical skills that include, among others, effective communication, team working, decision making, and leadership skills. Appropriately designed simulation-based and educational ECMO interventions can alleviate staff anxiety with regard to new technology and equipment, and boost confidence in relation to crisis management. In future, advances in simulation technology will allow for increased realism and higher fidelity, and subsequently further enhance the clinical team learning experience.
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ECLS: Past, present, and future
المؤلفون: Robert BartlettExtracorporeal life support (ECLS) is the prototype example of translational research. It began in laboratory studies to design, test, and characterize devices for prolonged extracorporeal circulation in the 1960s. The first clinical cases of ECLS for heart and lung failure were in the 1970s. These cases were met with skepticism, but the results in neonatal respiratory failure were encouraging. In the early 1980s, two centers conducted randomized trials in neonates, which demonstrated much higher survival with ECLS, and the term extracorporeal membrane oxygenation (ECMO) was coined. By 1986, there were 18 neonatal ECMO centers and data on 700 cases. These centers formed a consortium (The Extracorporeal Life Support Organization: ELSO) to maintain the registry, define guidelines and techniques, provide education, and hold an annual meeting.
In the 1990s, these centers expanded indications to older children with lung and heart failure. ECMO management for post-operative cardiac failure became standard in major pediatric heart centers. A multi-center randomized trial in the UK demonstrated a major survival advantage to ECMO in neonates. A few centers continued to evaluate and improve ECMO and extracorporeal CO2 removal (ECCOR) in adults with 50–60% survival in uncontrolled case series. At the ELSO meeting in 1999, a group met to plan a randomized trial in adult respiratory failure (ARDS). That study was carried out in the UK from 2002 to 2006 (the CESAR trial) using the same study design as the neonatal trial. The results were similar to the neonatal trial but adult intensivists were still skeptical, arguing that the single ECMO center in Leicester was just better at respiratory care than the other non-ECMO centers.
During all this time, we used modified pumps, oxygenators, and other equipment designed for cardiac surgery. A new medical profession of “ECMO specialist” developed to manage the ECMO system and patient. The number of specialists determined the number of ECMO cases that could be treated. Around 2008, a few companies made major improvements in these devices and manufactured specific ECMO machines. These machines were much safer, simpler, and reliable than the early ECMO equipment, and patients could be managed for weeks, primarily by the bedside ICU nurse with support from the specialist. This new equipment came along at the same time as the H1N1 flu pandemic of 2008–2009. ECMO was remarkably successful in saving the sickest patients, and adult intensivists scrambled to learn the technology. This was born out by two matched-pairs trials. ECMO for ARDS (acute respiratory disease syndrome) grew rapidly in adult intensive care units (ICU). The use of awake ambulatory ECMO as a bridge to lung transplantation has been expanded to all ECMO patients, in fact, to all ICU patients.1
Currently, ECMO is used for severe heart and lung failure in all ages. Research is focused on improving anticoagulation and devices, defining indications, and new applications like septic shock, ECPR for cardiac arrest, and EDCD to salvage organs for transplantation. Laboratory research has continued as clinical practice proceeded, and it currently includes an artificial placenta for very premature infants and four versions of implantable, wearable lungs for chronic support.2
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SWAC ELSO: Past, present and future
المؤلفون: Suneel PooboniThe South and West Asia Chapter of Extracorporeal Life Support Organisation (SWAC ELSO) was established in the year 2013 with the combined efforts of senior members from the ELSO and the ECMO society of India.1 It was established with the idea of improving the awareness and practice of ECMO in this part of the world. I am pleased to see the growth of the organisation in the next couple of years. This region is representative of the member countries from the SAARC (South Asian Association for Regional Cooperation) and Gulf region. In 2016, South Africa joined the chapter.
The population of the SWAC ELSO region is 2.56 billion, which is one-third of the world's population.2 South Asia, West Asia and Africa are unique with respect to the challenges offered to the healthcare delivery. There are wide variations in the economic potential of the countries. Healthcare inequalities do exist. ECMO is an intervention which is likely to bring the patient back to life in reversible cases of cardiorespiratory failure, when it is initiated at the right time. It does not come free of cost. Optimisation of the healthcare cost remains a priority. More efforts need to be put in this direction of developing a cost-effective model of ECMO.
Though I appreciate the way ECLS is provided in much of the developed world, there must be innovative ways to practice the science with the same principles in the resource-limited countries. Quality is very important and must be maintained. Collectively, similar-minded individuals with entrepreneurship should be able to develop a model of ECMO for resource-limited parts of the world. Infection is a main deterrent in achieving the optimal results globally.3 By adopting antibiotic stewardship principles and self-governance, infection can be brought under control. We do not need new antibiotics to achieve this goal.
The indications for ECMO have been varying in this part of the world. Though ARDS (adult respiratory distress syndrome) secondary to viral and bacterial pneumonias remains the predominant cause4 to seek support from ECMO, myocarditis due to scorpion stings, snake bites, supporting patients post poisoning like organo-phosphorous poisoning, celphos poisoning and exposure to various other poisons are some of the other examples. ARDS secondary to malaria, tuberculosis and other newer varieties of viral pneumonias (SARS, H1NI, H5N1, Dengue, etc.) offers exciting opportunities for application of this life-saving modality. Controlling drug-resistant infections is a major challenge and a priority. There are other challenges like lack of ideal transport facilities to cover long distances effectively. Cardiac ECMO as extended cardiopulmonary bypass is practised much more widely than respiratory ECMO.
The past has seen the development and standardisation of ECMO. We have been seeing the implications for solving the healthcare needs of mankind using ECLS (extracorporeal life support). With united efforts and mutual co-operation, we should make progress and help each other in unleashing the obstacles preventing the growth potential of ECLS. Life is a God-given gift. Let us join hands and save more lives. Let us show the unity in diversity.
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Qatar ECMO program: Past, present, and future
المؤلفون: Ibrahim Fawzy Hassan and Loua Al ShaikhThe clarion call for setting up a Qatar adult extracorporeal membrane oxygenation (ECMO) program came during the MERS-CoV outbreak in the Arabian Peninsula region.1 This carried a high mortality rate in those presenting with severe respiratory failure, and recent data from the “CESAR Trial” showed that treatment in a severe respiratory failure center with ECMO capabilities improved severe respiratory failure (SRF) patient survival.2
Owing to the regional novelty of the program, potential partners of external well-established ECMO programs were sought. The model of care hinged on medical versus surgical ECMO delivery. The balance tipped in favor of a medical model in view of the prevailing nature of the pandemic outbreak at the time. There is plenty of evidence demonstrating that the intensivist-led ECMO cannulation model is safe.3 The commissioning body also favored the notion of a severe respiratory failure outreach and retrieval service, delivered round-the-clock with the provision of on-site cannulation for ECMO and transportation thereafter.4,5 In early 2013, an ECMO partnership with a UK-based academic healthcare system was established with the view to train and initially mirror the UK-based ECMO program with subsequent tailoring and localization to fit the local need in Qatar. Team members were chosen locally, who were physicians, nurses, perfusionists, respiratory therapists, nutritionists, pharmacists, physiotherapists, and critical care paramedics.6 These underwent ECMO (VV modality) simulation and hands-on training in London as well as cadaveric cannulation training in Berlin, Germany. After extensive training abroad, the team members returned to Qatar where further training through simulation was carried out.7 This was supervised and signed off by the UK-based ECMO center. In April 2014, the first case qualifying for ECMO due to severe respiratory failure was treated at the Hamad Medical Corporation (HMC) ECMO center. Through the rest of 2014, the center was treating one patient per month. The survival rate was 100%. The first ECMO retrieval occurred in October 2014. This was carried with no recorded incidents. The year 2015 saw ECMO team size expansion and consolidation through in-house simulation courses and the HMC ECMO center joining ELSO. By the end of 2015, the center had treated 25 patients with a recorded survival rate of 70%. The year 2016 witnessed the introduction of VA ECMO modality, and the first aeromedical ECMO transfer occurred in June that year. Towards the end of 2016, the center began an ECMO fellowship program and registered its participation in multicenter ECMO trials. By the end of 2016, the center had carried out 50 runs of ECMO, with 10 patients dying while on ECMO (20% mortality). The ECMO patient survival to ICU discharge was 70% and to hospital survival was 68%. The future direction of the HMC ECMO program is to play a role of an adult regional center of excellence with not only land,8 but also aeromedical transport capability, and to consolidate on ECMO education and training, through simulation courses, for both static and transport modalities.7 Other future directions are, through local partnership, build on pediatric and cardiac ECMO, to introduce neonatal ECMO programs.
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The development of a mobile ECMO program
المؤلفون: Craig B. Campbell and Ahmed LabibRationale: Transport of critically ill patients on extracorporeal membrane oxygenation (ECMO) can be challenging; however, this has been demonstrated to be safe and feasible if undertaken by adequately trained teams,1–3 with appropriate equipment and a platform that can accommodate the team and allows full access to the patient.
The ECMO retrieval service is a key component of the severe respiratory failure (SRF-ECMO) program. The Hamad Medical Corporation (HMC) stakeholders realized the need for this “mobile” program as core to the ECMO program, given the geographical location of the hospital facilities and the complexity of the ECMO program.
The development of mobile ECMO is built on the established multidisciplinary Safe High Acuity Adult Retrieval Program (SHAARP) partnership between the HMC Ambulance Service and Medical Intensive Care Unit (MICU). The service operates on a Hub and Spoke model, whereby patients requiring ECMO are transferred to the MICU ECMO Centre at Hamad General Hospital (HGH). The major factor that influenced the initiation of the mobile ECMO program was the need for a secure and competent transport system to the only Adult ECMO Centre in Qatar with the necessary infrastructure and expertise to handle such complex cases. Mobile ECMO team: The need for a multidisciplinary, team-based approach to ECMO retrieval and transport was realized early due to the fact that the transport of these high acuity cases needed dedicated expertise. Our team model in Qatar is composed of two ECMO consultants, an ECMO nurse, a perfusionist, a respiratory therapist, and a critical care paramedic from the Ambulance Service, and is also supported by two ambulance paramedics (driver and attendant).
Transport of ECMO patients is a low volume high-risk event and hence there is a need for a specialized team. All team members received training and participated in retrievals in the UK on mobile ECMO. There is an ongoing training program,4 covering emergencies and techniques for safe movement of patients. The team dedication has resulted in the program being a success. To date, 13 retrievals have been successfully carried out including one intercontinental air-transfer, all without adverse outcomes. Mobile ECMO logistics: The mobile ECMO platform and trolley were custom designed. There was a recognition that a mobile SRF-ECMO service may require the team to transport a patient on ECMO, or to first stabilize on current therapy and then transport the patient to the acute care hospital to perform cannulation at a later time; if required.
As such, the adult Intensive Care Trolleys have been designed to provide ergonomic, safe, and comfortable transportation of high dependency intensive care patients, either on ECMO or on standard intensive care therapy. It is configured to meet the specific needs of the clinical team and designed to accommodate a wide range of medical apparatus. This stretcher carries all the basic intensive care monitoring accoutrements and is suited for pre-hospital, and inter- and intra-hospital transit care. The stretcher can hold a transport ventilator, monitor, infusion pumps, oxygen cylinders, a medication bag, and a miscellaneous pack. The mobile intensive care unit can safely accommodate the whole five-person team and specialized equipment in an appropriate working environment, with 360-degree access to the patient and equipment, in addition to the two paramedic crew driving the vehicle.
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How to maintain a quality ECMO program?
المؤلفون: Abdulsalam Saif IbrahimQuality and patient safety are core elements of a successful extracorporeal membrane oxygenation (ECMO) program. Patient survival, patient safety, and quality of life were the main considerations when establishing an ECMO service in Qatar, with the alternatives being death from refractory hypoxemia or permanent lung fibrosis and reduced quality of life as a result of harmful ventilation. The program strives to achieve these goals through a systematic, evidence-based, and structured program that does not use shortcuts, and integrates and provides high quality of care to improve survival rates among critically ill patients.
There is strong clinical evidence supporting the use of ECMO as a lifesaving procedure in critical patients, as it provides a viable alternative for patients with certain conditions that previously had high mortality rates.1 This leads us to define one of our objectives as improving our patients' outcome, while avoiding needless harm through the introduction of this service. Our objective was to establish an evidence-based but locally relevant structure for an ECMO center of excellence in the region, learning from other centers' experiences through strategic partnerships.2 The development involved an appropriately structured and staged education and training program for our staff to develop the required knowledge and skills and understanding the challenges associated with ECMO. We defined each team members' functions, roles, and responsibilities and established effective communication processes, thus inculcating a change to a collaborative culture of multi-professional teamwork. To ensure the best delivery of the service, we have ongoing support from experienced regional centers with high patient volumes, and focused and trained multidisciplinary teams, helping to positively impact patient outcomes in complex cases.
To ensure the maintenance of quality, our center believes that collecting accurate ECMO data in a timely manner is essential to track the progress, improve the logistics, report the metrics, and link them to international registries for benchmarking, sharing experience, and evaluating our performance. We use debriefing sessions, demonstrated as an effective reflective tool in simulation-based education,3 in our program's different daily activities to enhance the culture of our multidisciplinary teamwork. The success and program outcome is made and measured here, as everyone is accountable and contributes to analyzing the available data of our patients. The team reviews the structure, processes, and outcome using the quality tools of plan–do–study–act, root-cause analysis, process mapping, etc. Clear tasks and assignments are distributed and SMART goals are set.4 Crisis Resource Management (CRM) is another valuable component in developing and maintaining a quality service in the ECMO program, and empowerment of the team to ensure expectations are met through effective communication, involvement, skill enhancement, professional development, recredentialing, and setting the standards.5 Our center invests in developing and running simulation-based workshops and training sessions that provide additional learning opportunities beyond the traditional quality improvement tools.6
In conclusion, it needs a persistent effort to maintain a quality ECMO program, with clear objectives, quality standards, ongoing training, and good communication as important elements for success.
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Acute respiratory failure: From intubation to ECMO
المؤلفون: Ibrahim Fawzy HassanIntroduction: Acute severe respiratory failure poses a major treatment challenge which stubbornly carries high mortality and morbidity rates. Here, we review PaO2/FiO2 (PF) ratio and disease severity, and discuss protective lung ventilation and the rescue therapies, and when to use what? PF ratio alone is not sufficient to determine disease severity: A recent study by Villar and colleagues demonstrated that only 38% of patients who were classified as severe acute respiratory disease syndrome (ARDS) patients based on the PF ratio met the actual severe ARDS criteria after a standardized ventilator setting. In a recent trial conducted by Caironi1 and colleagues, alteration in the positive end-expiratory pressure (PEEP) level affected the PF ratio and disease severity. Using the PF ratio alone as the major determinant for disease severity will increase the risk of selecting the wrong therapy for the patient. Protective lung ventilation: Between 1998 and 2000, two prospective randomized controlled trials (RCT's) showed that lower tidal volumes (VT) decrease mortality compared with higher VT.2,3 Retrospectively, plateau pressure (pPlat) < 32 cmH2O was the major difference between survival and non-survival, hence VT 4–6 mL/kg of predicted body weight (PBW) and pPlat < 30 cmH2O became the standard of care.
Several papers challenged the pPlat value of 30; in 2005, Hager4 and colleagues could not identify a safe upper limit for plateau pressures in patients with ARDS. Moreover, VT reduction would have improved the outcome, even in patients who already had pPlat < 30 cmH2O. More recently, Amato5 and colleagues demonstrated that driving pressure was the ventilation variable that best stratified risk independently of concomitant variations in PEEP and plateau pressure. This was supported by another retrospective study on ECMO patients by Serpa et al.6 That opened the question: “What is protective lung ventilation?” Rescue therapies: The two proven rescue therapies to date are: “Prone Position” and “ECMO”.
Prone Position enhances lung recruitment in a potentially recruitable lung by various mechanisms, releasing the diaphragm, decreasing the effect of heart and lung weight and shape on lung tissue, decreasing the lung compression by the abdomen, and releasing the lower lobes, which improves gas exchange and decreases mortality in severe ARDS patients.
ECMO provides extracorporeal gas exchange with no effect on lung recruitment. It affords lung rest and works well for the non-recruitable lung. It has been shown to improve survival for certain groups of patients in high-performance ECMO centers.7
It is important to note that the delay in utilizing such rescue therapies worsen the outcome. Discussion: PF ratio combined with standardized ventilator setting is superior to PF ratio alone to determine disease severity. This is essential to determine the correct therapy for the right patient. Lung protective ventilation strategy remains the corner stone for decreasing morbidity and mortality in ARDS patients. However, the lung protective concept may require to be tailored to disease severity; pPlat of 30 cmH2O might be safe for a patient with moderate ARDS but may be deleterious in the severe ARDS patient. Moreover, the driving pressure as the safety guard needs to be explored in more RCTs. Clear definition of “Failure of conventional ventilation” needs to be agreed upon and a clear pathway for trial of prone ventilation versus directly initiating ECMO therapy needs to be defined.
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ECMO cannulation by non-surgeons is safe
المؤلفون: Vincent Alfred PellegrinoThe extracorporeal membrane oxygenation (ECMO) cannulae can be safely inserted into the jugular and femoral regions using a percutaneous dilation technique or by open surgical cannulation. Percutaneous dilation that avoids skin cutting can achieve a tight seal between skin, vessels and cannulae. This avoids bleeding associated with surgical dissection and limits tissue damage. Surgical dissection is also associated with additional risks of wound breakdown and seroma formation in critically ill patients (particularly those requiring long-term immunosuppression). Non-surgical cannulation also offers the advantage of avoiding the need for additional patient transfer to the operating theatre. Moreover, it has been safely performed in a variety of settings, without affecting surgical workflow. Percutaneous cannulation can be performed by a broad range of hospital medical specialists and obviates the need for surgical attendance in time critical settings. Non-surgical cannulation for both veno-arterial and veno-venous ECMO is well established in many experienced ECMO centres and is an entrenched practice.1,2
Risks associated with “blind” percutaneous cannulation can be greatly reduced with the use of real-time vascular ultrasound, which is now commonplace in modern intensive care and anaesthetic settings. In conjunction with real-time echocardiography, complete visualisation of guide-wire and cannula insertion is possible. Other radiological support can also increase the safety of percutaneous insertion.
Technical training and skill acquisition is required for safe percutaneous cannulation with ultrasound. It should not be performed by those without training and credentialing. Direct visualisation of the vessel does not remove the risks of serious complications from ECMO cannulation.
Utility of ultrasound in ECMO cannulation include:
• Anatomical assessment of the target vessel and cannulation planning. This includes the detection of intravascular thrombosis prior to cannulation as well as the detection of peripheral vascular disease;
• Real-time needle localisation facilitates accurate needle insertion, which reduces the risks of inadvertent sapheno-femoral junction venous cannulation and inadvertent profunda femoris artery injury (femoral artery cannulation), and ultrasound assessment of guidewire placement allows confirmation of position prior to dilation;
• Optimal siting of venous cannulae tips;
• Detection and avoidance of cardiac abnormalities – particularly involving the right atrium such as Chiari network or prominent, remnant eustachian and thebesian valves which can have an impact on correct siting of access cannulae.
Surgical cannulation is required for subclavian arterial return ECMO configurations and central ECMO configurations. Central cannulation should not be used unless adequate support cannot be achieved by peripheral cannulation due to the very high rates of bleeding and serious complications.
Surgical repair is also standardly required for vascular repair following the removal of an arterial ECMO cannula.
Ideally patients should have access to timely ECMO support and should have their configuration modified to best meet their needs when required. Thus, access to timely non-surgical cannulation and recourse to surgical cannulation for specific needs is the optimal model of care.
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ECMO physiology
المؤلفون: Abeer Mahmoud Ahmed Al JajaTemporary mechanical cardiopulmonary support may be used intraoperatively to facilitate cardiac surgery. Over the past decade, this intervention has been extended for prolonged use in the intensive care unit (ICU) as extracorporeal membrane oxygenation (ECMO).1
Two types of ECMO exist in clinical practice: veno-arterial (VA) and veno-venous (VV). VV ECMO provides support to the pulmonary system by extracting blood from the right atrium, oxygenating it and returning it to the right atrium, where the patient remains dependent on their own circulation. In VA ECMO, blood is extracted from the right atrium and returned to the arterial system, bypassing the heart and lungs, which provides both respiratory and hemodynamic support.2
Patients who require ECMO support receive anticoagulation with heparin3 before the cannulas are inserted, either in the right jugular area or in the left/right femoral area(s). In VV ECMO, blood is drained from the venous cannula placed typically in the inferior vena cava (IVC), and returned through a cannula with its tip at close proximity of the right atrium, either through the femoral vein or through the right internal jugular vein. In VA ECMO, blood is drained from the IVC and returned through right femoral artery or the aorta to the systemic cannulation.2
ECMO support is initiated when the patient is connected to the ECMO circuit. The deoxygenated blood will be withdrawn from the patient through the access line under negative pressure (usually created by a centrifugal pump) entering the oxygenator (artificial lung membrane), where gas exchange occurs. Blood is then returned back to the patient through the return line.4 Oxygenated Flow on ECMO machine is controlled across the hollow fiber membrane. The blood flows outside of the fibers and the gas flows through the fibers in a counter current flow pattern. The non-direct contact between blood and gas reduces blood trauma. The gas exchange occurs through diffusion due to the concentration gradient between O2 and CO2. Oxygenated blood is then returned back to the patient through the return line.4
Pressures within an ECMO circuit are highly important and need to be understood (access, pre-membrane, and post-membrane pressures) to quickly identify potential issues. The transmembrane pressure (TMP) is the difference between the pre- and post-membrane pressures. The TMP baseline should be monitored when ECMO is initiated and be compared with the TMP trend during the ECMO run, as it reflects the function of the circuit membrane. The membrane acts as the blood oxygenator and should be regularly checked for clots.
The patient oxygen saturation, temperature, hemoglobin, sedation, preload, and afterload will be continuously monitored. FiO2 and sweep gas flow is adjusted according to pre- and post-membrane blood gases.
Anticoagulation is sustained while the patient is on ECMO and it is monitored through the activated clotting time (ACT). ACT of 180–210 seconds or APTT of 35–45 seconds are accepted.3 The use of Bioline coating on the internal circuit surfaces improves biocompatibility of extracorporeal circulation system devices: oxygenators, cannulas, connectors, centrifugal pumps, and tubes by mimicking human tissue.
It is highly important to understand the possible complications that may occur while patients are on ECMO, whether it is patient related (bleeding, thromboembolism, etc.) or ECMO circuit related.1 Therefore, all safety devices within an ECMO machine and circuit should be connected properly, functioning well, and checked continuously until the patient is weaned from ECMO.4
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Management strategies on venovenous extracorporeal membrane oxygenation
المؤلفون: Ali Ait HssainThe use of venovenous extracorporeal membrane oxygenation (VV-ECMO) for severe acute respiratory failure (ARF) has considerably increased worldwide. Therefore, extracorporeal membrane oxygenation (ECMO) teams called for practical guidelines with clear objectives on how to manage ECMO on daily basis.1 All classical topics of intensive care management have been put in perspective with the use of ECMO, opening multiple areas of research. Good teamwork is the central pillar of any ECMO program.
After starting an ECMO run, the medical team has to deal with a triangle including the patient, the ECMO machine, and their interaction. This unique interdependence makes the management challenging, as any change occurring on one side (patient or ECMO) will affect the other side. The priority is to diagnose and treat the cause of ARF. Bronchoscopy showed a reasonable safety for diagnostic yield and clearing airways. The optimization of the oxygen delivery is primordial within the acute period and is represented by matching the ECMO flow and the cardiac output, maintaining an adapted level of hemoglobin, and decreasing causes of high oxygen consumption.2 The management of volume status is essential for keeping a precise balance between the patient and the machine.
Echocardiography is an essential tool that provides much information before cannulation on hemodynamic, access insufficiency once the patient is on ECMO, initial cannula positioning or readjustment, and finally tolerance to ECMO weaning before and after decannulation.3
Once ECMO provides adequate oxygenation delivery for the patient, the different parameters of mechanical ventilation have to be readjusted with an actual trend to decrease most of them: FiO2 (25%), inspiratory pressure (10 cm H2O), and respiratory rate (10 cycles/min) that results in ultra-protective lung ventilation with an expected tidal volume in a range of 1–3 ml/kg.4 More than knowing the “best” positive end expiratory pressure, a low driving pressure less than 1 cm H2O has to be targeted.5 This is to ensure that the lungs can rest and recover over time. The exact duration required to reach these settings to allow an improvement on oxygenation is unpredictable. The weaning process is challenging as the gas exchange function improvement and the lung compliance recovery are sometimes not concomitant. It requires daily monitoring to allow early extubation while on ECMO. The anticoagulation has to be balanced not only to avoid any clots in the circuit when just connected, but also to avoid any bleeding.
Analgesia and sedation are important for the initial oxygen consumption after cannulation and have to be minimized from the second day to the third day. The goal is for the patient to receive sufficient oxygenation without pain. Depending on their tolerance, patients will sometimes be awake while on ECMO. Then, an active physiotherapy (PT) program including mobilization, sitting on the edge of the bed, standing up, and walking should follow the passive PT started from the first day on ECMO. Acute renal failure is common during ECMO and should be prevented and treated with renal replacement therapy. Many other points including nutritional support and nosocomial infection prevention are specifically integrated in the patient management.
In summary, the management strategies on VV-ECMO are complex and require to master critical care and ECMO knowledge combined with a strong collaborative multidisciplinary environment. The goal is to wean patients from ECMO as soon as clinical parameters permit it while avoiding ECMO-related complications.
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Role of echocardiography in ECMO
المؤلفون: Poonam Malhotra KapoorIntroduction: Echocardiography (ECHO) plays a fundamental role in the management of patients supported with extracorporeal membrane oxygenation (ECMO).1 It is particularly useful for the detection of cardiac complications that may arise during ECMO. It helps in many ways during the ECMO run, as presented in Table 1.
ECHO helps to identify or exclude new reversible pathology, which could be the actual cause of patient hemodynamic deterioration (cardiac tamponade/undiagnosed valvular lesions and left ventricular (LV) dysfunction), thus avoiding the need for ECMO support. It also helps to provide information about contraindications, for example aortic dissection. Identification of significant aortic regurgitation (AR) is a relative contraindication in veno-arterial (VA) ECMO, in which the LV afterload is increased, leading to a further increase in AR. It also provides information on aortic atherosclerosis, thus guiding the intensivist in deciding the cannulation sites (central versus peripheral) or the technique (surgical versus percutaneous). ECHO also helps to evaluate the right heart morphology for any structural abnormality, which could impede the positioning of venous cannula for veno-venous (VV) ECMO or VA ECMO. ECHO aids in diagnosing complications during ECMO: The diagnosis of upper limb hyperperfusion relies heavily on clinical features, with imaging utilized more to determine etiology. Transthoracic echocardiography (TTE) may add incremental value to the diagnosis of arterial upper limb hyperperfusion during ECMO support with an axillary artery, and it can be easily and quickly performed at the bedside.2
ECHO has a crucial role during ECMO cannulation as it guides the correct placement of the ECMO cannulas. TTE may not have the adequate spatial resolution to guide ECMO cannulation, and therefore transesophageal echocardiography (TEE) is essential. There should be a direct communication between the operator and the echocardiologist as to the site of the indented cannula insertion. For example, in VV ECMO, when one cannula is used for access and another to return the blood, the position of the access cannula tip is in the proximal inferior vena cava (IVC), just before the entry into the right atrium (RA). On the other hand, the optimal position for the return cannula is in the mid-RA, but well clear from the interatrial septum and the tricuspid valve. This can be determined with ECHO.
ECHO is critical in the detection and management of specific complications that may arise during ECMO support. Because TTE has limited spatial resolution, TEE is usually used to detect these complications. ECHO enables rapid assessment of cannula positioning, cardiac filling, cardiac function, and evidence of chamber compression from tamponade. The detection of cardiac tamponade and the assessment of the significance of pericardial effusion or collection can be difficult in patients supported with ECMO as the heart is in a partially bypassed state.
Complications in any part of the ECMO circuit can be well seen on ECHO as well as thrombosis on 2D or 3D ECHO. Conclusion: ECHO is mandatory during the initiation of ECMO, cannula insertion, hemodynamic monitoring, and detection of complications during weaning.
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Persistent hypoxemia on ECMO
المؤلفون: Steven A. ConradExtracorporeal membrane oxygenation (ECMO) is used to support patients with hypoxemia due to severe respiratory failure. Hypoxemia can persist during ECMO as a result of reduction in mechanical ventilatory support as part of a lung protective strategy, following which gas exchange provided by the native lungs is reduced or absent. If tissue oxygen delivery is maintained, mild to moderate hypoxemia will be well tolerated, but if tissue hypoxia develops, then the cause of hypoxemia must be addressed and corrected.
Patterns of hypoxemia are dependent on the mode of ECMO support. During veno-venous support for respiratory failure, hypoxemia is global, with all tissues receiving hypoxemic blood. When femoral veno-arterial support is used in the presence of respiratory failure, then differential hypoxemia can result, with hypoxemia limited to the upper part of the body. The approach to hypoxemia is dependent on whether veno-venous (VV) or veno-arterial (VA) ECMO is used.
Adequate oxygen saturation on VV ECMO requires adequate hemoglobin, a membrane lung operating below its rated flow, low recirculation, and extracorporeal circuit flow that captures most of the cardiac output. The approach to hypoxemia during VV ECMO includes addressing each of these. Identifying and limiting recirculation will improve effective extracorporeal flow. Anemia has two detrimental effects. First, it limits oxygen transfer through the membrane lung. Second, it increases oxygen extraction resulting in low mixed venous oxygen saturation that increases the effective venous admixture with circuit blood. Transfusion to near normal levels will help improve oxygen saturation. Increasing effective extracorporeal flow to capture at least 60% of the cardiac output is necessary.1 If the extracorporeal flow fraction is less than 60% due to an increased cardiac output, then reducing cardiac output through reducing exogenous catecholamines, use of beta blockade,2 or hypothermia3 will help improve the extracorporeal flow fraction. Hypothermia has the added benefit of reducing oxygen consumption and therefore improving mixed venous saturation. A final option is to leverage the native lungs, such as through prone positioning, as long as lung protective strategies can be maintained.4
Oxygen saturation on femoral VA ECMO is typically normal (>90%). The upper part of the body is provided with blood from the left ventricle that has been saturated by normally functioning lungs. The lower part of the body is provided with fully saturated blood from the extracorporeal circuit. The two circulations meet at some point in the aorta that depends on the relative magnitude of flow rate in these two circulations. If there is pulmonary dysfunction, then the blood ejected by the left ventricle will be hypoxemic, and tissues perfused proximal to the mixing point will be perfused with hypoxemic blood, while the lower body will have a normal saturation. Management of this differential hypoxemia is through improvement of pulmonary gas exchange if possible, increasing extracorporeal flow to decrease pulmonary blood flow, or conversion of VA ECMO to VVA (hybrid veno-arterial and veno-venous).
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Practical proning on ECMO
المؤلفون: Kathleen J.R. DalyThe prone position has been used successfully for many years to improve oxygenation in patients who require mechanical ventilatory support for management of acute respiratory distress syndrome (ARDS). Proning improves oxygenation by optimizing lung recruitment and ventilation–perfusion matching. The following improved outcomes have been shown: when the prone position is used for moderate to severe ARDS; when used in combination with protective lung ventilation; and when the duration of the proning session is >16 h.1 However, proning is not without contraindications and complications.2 There are only two absolute contraindications to proning, which are suspected raised intracranial pressure and spinal instability. Some high-risk relative contraindications that may preclude proning include: recent sternotomy, facial surgery, and severe haemodynamic instability. Other relative contraindications include an open abdomen, pregnancy, and multiple traumas with unstable fractures. Respiratory ECMO is not a contraindication to proning. The risk of proning needs to be weighed against the potential lifesaving benefits of proning. The Extracorporeal Life Support Organisation (ELSO) guidelines for adult respiratory failure recommend the consideration of introducing prone positioning therapy to patients receiving ECMO, if there is posterior consolidation of the lung fields with some lung fields open anteriorly. The guidelines recommend exercising caution to prevent the dislodgement of the ECMO cannulas.3 Expert nursing care can prevent most complications occurring. Complications associated with the mechanics of proning include transient desaturation, haemodynamic instability, accidental extubation, and central lines displacement. Other complications that can occur during proning include the development of pressure ulcers, vomiting, the need for increased sedation ± paralysis, nerve damage, and bleeding from ECMO cannula sites. To reduce the risk of potential complications, trained critical care staff, strict protocols, and procedures for the implementation of proning, including the mechanics of the proning procedure itself together with the care of the patient and circuit whilst the patient is proned, must be implemented. An experienced team of critical care staff who routinely use this intervention and who are familiar with the procedure are required to facilitate the mechanics of the proning process and the ongoing management of the patient to ensure the safety of both the patient and the ECMO circuit. There is no standard method for moving a patient from supine to the prone position. Most centres that prone adult patients use a “double sheet rolling” technique, whereby the patient is securely wrapped between two sheets and then manually turned from the supine to prone position through careful team coordination.3 Commercially available beds are also available which can initiate, maintain, and facilitate prone positioning. The recommended minimum number of staff required to safely prone an adult patient are five members of staff, six if the patient is on ECMO (four to prone, one to manage the airway, and one to manage the ECMO circuit), although ideally there should be seven members of the team, eight if the patient is on ECMO (six to prone, one to manage the airway, and one to manage the ECMO circuit) (local guidance GSTT).
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Anticoagulation on extracorporeal membrane oxygenation (ECMO)
المؤلفون: Praveen KhilnaniIntroduction: Extracorporeal circulation has been around for more than half a century, but many questions remain regarding how to best achieve anticoagulation in a patient on extracorporeal membrane oxygenation (ECMO). Although unfractionated heparin is the predominant agent used for cardiopulmonary bypass, the amount required and how best to monitor its effects are still unresolved. Extracorporeal circulation is associated with the activation of clotting cascade upon contact with a foreign surface of the ECMO circuit; therefore, heparin or a heparin-bonded circuit is used for anticoagulation. Objectives: To describe commonly used tests to monitor anticoagulation status and ways to maintain a clot-free circuit with least damage to circulating platelets. Methods: A literature search was conducted on PubMed for articles published in peer-reviewed medical journals in English in the past 10 years. Results: Various evidence-based facts emerged. Upon initiation of ECMO flow, there is a strong inflammatory response almost similar to systemic inflammatory response syndrome (SIRS) with the release of various cytokine mediators such as interleukins and tumor necrosis factor as well as a trigger to arachidonic acid metabolism with the release of prostaglandins and destruction of platelets.1 Monitoring of anticoagulation status requires close monitoring of activated clotting times (ACTs), a close watch of platelet count, looking for evidence of heparin-induced thrombocytopenia (HIT), and finally, greater use of thromboelastogram (TEG) for precise analysis of coagulation status (Figs. 1 and 2). The ECMO circuit needs to be physically monitored (lines, pump head, oxygenator) for any clots as well as the values of the pre- and post-membrane pressures to detect clots in the membrane oxygenator. In view of a higher duration of ECMO run when compared with cardiopulmonary bypass, it is particularly challenging to achieve an optimal anticoagulation keeping in mind inflammation, disseminated intravascular coagulation, as well as side effects such as HIT.2 Treatment of bleeding/clotting emergencies involves early detection and use of anticoagulation reversal agents with or without transfusion of blood or blood products with full round-the-clock support by blood bank. Although heparin-coated circuits have been safely used for extracorporeal lung assist with little or no systemic anticoagulation,3 prospective studies are clearly needed to determine whether this approach is advantageous, and it would seem appropriate to develop heparin coating for silicone-based membrane oxygenators.Figure 1. TEG report on clot characteristics (http://marylandccproject.org/core-content/utility-teg-blood-component-therapy/).
Figure 2. Interpretation of thromboelastogram.4
Conclusion: Various tests are available to monitor the anticoagulation status of a patient on ECMO with bedside availability. It is important to perform physical inspection of the ECMO circuit as well as to monitor pre- and post-membrane pressures frequently, in order to detect clots in the circuit, and to further regulate heparin therapy. Activated clotting time (ACT) by far remains the most commonly used monitoring tool at most ECMO centers.
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