Long-Term Venovenous Extracorporeal Membrane Oxygenation Support for Acute Respiratory Distress Syndrome

Liberation From Venovenous Extracorporeal Membrane Oxygenation for Respiratory Failure: A Scoping Review

BACKGROUND

Safe and timely liberation from venovenous extracorporeal membrane oxygenation (ECMO) would be expected to reduce the duration of ECMO, the risk of complications, and costs. However, how to liberate patients from venovenous ECMO effectively remains understudied.

RESEARCH QUESTION

What is the current state of the evidence on liberation from venovenous ECMO?

STUDY DESIGN AND METHODS

We systematically searched for relevant publications on liberation from venovenous ECMO in Medline and EMBASE. Citations were included if the manuscripts provided any of the following: criteria for readiness for liberation, a liberation protocol, or a definition of successful decannulation or decannulation failure. We included randomized trials, observational trials, narrative reviews, guidelines, editorials, and commentaries. We excluded single case reports and citations where the full text was unavailable.

RESULTS

We screened 1,467 citations to identify 39 key publications on liberation from venovenous ECMO. We then summarized the data into five main topics: current strategies used for liberation, criteria used to define readiness for liberation, conducting liberation trials, criteria used to proceed with decannulation, and parameters used to predict decannulation outcomes.

INTERPRETATION

Practices on liberation from venovenous ECMO are heterogeneous and are influenced strongly by clinician preference. Additional research on liberation thresholds is needed to define optimal liberation strategies and to close existing knowledge gaps in essential topics on liberation from venovenous ECMO.

Outcomes of Extremely Prolonged (> 50 d) Venovenous Extracorporeal Membrane Oxygenation Support

OBJECTIVES

There has been a sustained increase in the utilization of venovenous extracorporeal membrane oxygenation (ECMO) over the last decade, further exacerbated by the COVID-19 pandemic. We set out to describe our institutional experience with extremely prolonged (> 50 d) venovenous ECMO support for recovery or bridge to lung transplant candidacy in patients with acute respiratory failure.

DESIGN

Retrospective cohort study.

SETTING

A large tertiary urban care center.

PATIENTS

Patients 18 years or older receiving venovenous ECMO support for greater than 50 days, with initial cannulation between January 2018 and January 2022.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One hundred thirty patients were placed on venovenous ECMO during the study period. Of these, 12 received prolonged (> 50 d) venovenous ECMO support. Eleven patients (92%) suffered from adult respiratory distress syndrome (ARDS) secondary to COVID-19, while one patient with prior bilateral lung transplant suffered from ARDS secondary to bacterial pneumonia. The median age of patients was 39 years (interquartile range [IQR], 35-51 yr). The median duration of venovenous ECMO support was 94 days (IQR, 70-128 d), with a maximum of 180 days. Median time from intubation to cannulation was 5 days (IQR, 2-14 d). Nine patients (75%) were successfully mobilized while on venovenous ECMO support. Successful weaning of venovenous ECMO support occurred in eight patients (67%); 6 (50%) were bridged to lung transplantation and 2 (17%) were bridged to recovery. Of those successfully weaned, seven patients (88%) were discharged from the hospital. All seven patients discharged from the hospital were alive 6 months post-decannulation; 83% (5/6) with sufficient follow-up time were alive 1-year after decannulation.

CONCLUSIONS

Our experience suggests that extremely prolonged venovenous ECMO support to allow native lung recovery or optimization for lung transplantation may be a feasible strategy in select critically ill patients, further supporting the expanded utilization of venovenous ECMO for refractory respiratory failure.

Timing of Lung Transplant Referral in Patients with Severe COVID-19 Lung Injury Supported by ECMO

Severe respiratory failure caused by COVID-19 often requires mechanical ventilation, including extracorporeal membrane oxygenation (ECMO). In rare cases, lung transplantation (LTx) may be considered as a last resort. However, uncertainties remain about patient selection and optimal timing for referral and listing. This retrospective study analyzed patients with severe COVID-19 who were supported by veno-venous ECMO and listed for LTx between July 2020 and June 2022. Out of the 20 patients in the study population, four who underwent LTx were excluded. The clinical characteristics of the remaining 16 patients were compared, including nine who recovered and seven who died while awaiting LTx. The median duration from hospitalization to listing was 85.5 days, and the median duration on the waitlist was 25.5 days. Younger age was significantly associated with a higher likelihood of recovery without LTx after a median of 59 days on ECMO, compared to those who died at a median of 99 days. In patients with severe COVID-19-induced lung damage supported by ECMO, referral to LTx should be delayed for 8-10 weeks after ECMO initiation, particularly for younger patients who have a higher probability of spontaneous recovery and may not require LTx.

The Lung Transplant Candidate, Indications, Timing, and Selection Criteria

Lung transplantation can be lifesaving for patients with advanced lung disease. Demographics are evolving with recipients now sicker but determining candidacy remains predicated on one's underlying lung disease prognosis, along with the likelihood of posttransplant success. Determining optimal timing can be challenging, and most programs favor initiating the process early and proactively to allow time for patient education, informed decision-making, and preparation. A comprehensive, multidisciplinary evaluation is used to elucidate disease progrnosis and identify risk factors for poor posttransplant outcomes. Candidacy criteria vary significantly by center, and close communication between referring and transplant providers is necessary to improve access to transplant and outcomes.

Outcomes of Venovenous Extracorporeal Membrane Oxygenation in Viral Acute Respiratory Distress Syndrome

Our study assessed the relationship between the duration of venovenous extracorporeal membrane oxygenation (V-V ECMO) and patient outcomes. We studied patients undergoing V-V ECMO support for acute respiratory distress syndrome (ARDS) between 2009 and 2017 who were reported to the Extracorporeal Life Support Organization registry. We evaluated survival, major bleeding, renal failure, pulmonary complications, mechanical complications, neurologic complications, infection, and duration of V-V ECMO support. Multivariable regression modeling assessed risk factors for adverse events. Of the 4,636 patients studied, the mean support duration was 12.2 ± 13.7 days. There was a progressive increase in survival after the initiation of V-VECMO, peaking at a survival rate of 73% at 10 days of support. However, a single-day increase in V-V ECMO duration was associated with increased bleeding events (odds ratio [OR] 1.038; 95% confidence interval [CI]: 1.029-1.047; p < 0.0001), renal failure (OR 1.018; 95% CI: 1.010-1.027; p < 0.0001), mechanical complications (OR 1.065; 95% CI: 1.053-1.076; p < 0.0001), pulmonary complications (OR 1.04; 95% CI: 1.03-1.05; p < 0.0001), and infection (OR 1.04; 95% CI: 1.03-1.05; p < 0.0001). V-V ECMO progressively increases survival for ARDS over the first 10 days of support. Thereafter, rising complications associated with prolonged durations of support result in a progressive decline in survival.

Be Patient: Prolonged Extracorporeal Membrane Oxygenation Support Including Full System Switch With Favorable Outcome

Despite tremendous advances in treatment, acute respiratory distress syndrome (ARDS) remains a disease with high mortality (42-48%). Veno-venous extracorporeal membrane oxygenation (VV-ECMO) is often used as a last treatment option, which poses complex problems for the treatment team, especially with prolonged ECMO support. We report an interesting case of a 40-year-old female patient who developed influenza pneumonia leading to ARDS and subsequently requiring ECMO. Due to severe clotting complications, a prolonged ECMO run time with numerous filter changes was required. After a total of 56 days of ECMO therapy, the patient was successfully weaned. Fortunately, further in the course of treatment, complete recovery with restitutio ad integrum was achieved. A distinguishing feature of this case report is the description of a complete ECMO system change and the concurrent use of two ECMO systems for the same patient. Additionally, we provide data on the patient's current health-related quality of life as measured using the World Health Organization Disability Assessment Schedule 2.0.

Indications for Lung Transplantation and Patient Selection

Globally, thousands of patients undergo lung transplantation owing to end-stage lung disease each year. As lung transplantation evolves, recommendations and indications are constantly being updated. In 2021, the International Society for Heart and Lung Transplantation published a new consensus document for selecting candidates for lung transplantation. However, it is still difficult to determine appropriate candidates for lung transplantation among patients with complex medical conditions and various diseases. Therefore, it is necessary to analyze each patient’s overall situation and medical condition from various perspectives, and ongoing efforts to optimize the analysis will be necessary. The purpose of this study is to review the extant literature and discuss recent updates.

Intracranial haemorrhage in adult patients on venoarterial extracorporeal membrane oxygenation

AIMS

Intracranial haemorrhage (ICH) is one of the most serious complications of adult patients treated with venoarterial extracorporeal membrane oxygenation (VA-ECMO) and is associated with increased morbidity and mortality. However, the prevalence and risk factors of ICH in this cohort are still insufficiently understood. We hypothesized that a considerable proportion of patients undergoing VA-ECMO support suffer from ICH and that specific risk factors are associated with the occurrence of ICH. Therefore, the purpose of this study was to further investigate the prevalence and associated mortality as well as to identify risk factors for ICH in VA-ECMO patients.

METHODS AND RESULTS

We conducted a retrospective multicentre study including adult patients (≥18 years) treated with VA-ECMO in cardiac intensive care units (ICUs) at five German clinical sites between January 2016 and March 2020, excluding patients with ICH upon admission. Differences in baseline characteristics and clinical outcome between VA-ECMO patients with and without ICH were analysed and risk factors for ICH were identified. Among the 598 patients included, 70/598 (12%) developed ICH during VA-ECMO treatment. In-hospital mortality in patients with ICH was 57/70 (81%) and 1-month mortality 60/70 (86%), compared to 332/528 (63%) (P = 0.002) and 340/528 (64%) (P < 0.001), respectively, in patients without ICH. Intracranial haemorrhage was positively associated with diabetes mellitus [odds ratio (OR) 2, 95% confidence interval (CI) 1.11-3.56; P = 0.020] and lactate (per mmol/L) (OR 1.06, 95% CI 1.01-1.11; P = 0.020), and negatively associated with platelet count (per 100 G/L) (OR 0.32, 95% CI 0.15-0.59; P = 0.001) and fibrinogen (per 100 mg/dL) (OR 0.64, 95% CI 0.49-0.83; P < 0.001).

CONCLUSION

Intracranial haemorrhage was associated with a significantly higher mortality rate. Diabetes mellitus and lactate were positively, platelet count, and fibrinogen level negatively associated with the occurrence of ICH. Thus, platelet count and fibrinogen level were revealed as potentially modifiable, independent risk factors for ICH. The findings address an area with limited data, provide information about risk factors and the epidemiology of ICH, and may be a starting point for further investigations to develop effective strategies to prevent and treat ICH.

A Comparison of Anticoagulation Strategies in Veno-venous Extracorporeal Membrane Oxygenation

Bleeding remains a major source of morbidity associated with veno-venous extracorporeal membrane oxygenation (VV-ECMO). Moreover, there remains significant controversy, and a paucity of data regarding the ideal anticoagulation strategy for VV-ECMO patients. All patients undergoing isolated, peripheral VV-ECMO between January 2009 and December 2014 at our institution were retrospectively reviewed. Patients (n = 123) were stratified into one of three sequential eras of anticoagulation strategies: activated clotting time (ACT: 160-180 seconds, n = 53), high-partial thromboplastin time (H-PTT: 60-80 seconds, n = 25), and low-PTT (L-PTT: 45-55 seconds, n = 25) with high-flow (>4 L/min). Pre-ECMO APACHE II scores, SOFA scores, and Murray scores were not significantly different between the groups. Patients in the L-PTT group required less red blood cell units on ECMO than the ACT or H-PTT group (2.1 vs. 1.3 vs. 0.9; p < 0.001) and patients in the H-PTT and L-PTT group required less fresh frozen plasma than the ACT group (0.33 vs. 0 vs. 0; p = 0.006). Overall, major bleeding events were significantly lower in the L-PTT group than in the ACT and H-PTT groups. There was no difference in thrombotic events. In this single-institution experience, a L-PTT, high-flow strategy on VV-ECMO was associated with fewer bleeding and no difference in thrombotic events than an ACT or H-PTT strategy.

Fracture of dual lumen cannula leading to cerebrovascular accident in a patient supported with ECMO

Extended duration extracorporeal membrane oxygenation (ECMO), using dual-lumen cannulas, is being used with increased frequency to support patients, including those with COVID-19; both as a bridge to transplant and lung recovery. During such an extended duration of support, there are several factors that might lead to the attrition of the physical structure of the ECMO cannulas, predisposing them to the risk of fracture. Although rare, fracture of the ECMO cannula can be a potentially lethal event. Here, we present a case where fracture of a dual lumen cannula during veno-venous (VV) ECMO support resulted in a cerebrovascular accident. We discuss the potential contributing factors and suggest steps to mitigate the risks for such a complication.

Consensus document for the selection of lung transplant candidates: An update from the International Society for Heart and Lung Transplantation

Tens of thousands of patients with advanced lung diseases may be eligible to be considered as potential candidates for lung transplant around the world each year. The timing of referral, evaluation, determination of candidacy, and listing of candidates continues to pose challenges and even ethical dilemmas. To address these challenges, the International Society for Heart and Lung Transplantation appointed an international group of members to review the literature, to consider recent advances in the management of advanced lung diseases, and to update prior consensus documents on the selection of lung transplant candidates. The purpose of this updated consensus document is to assist providers throughout the world who are caring for patients with pulmonary disease to identify potential candidates for lung transplant, to optimize the timing of the referral of these patients to lung transplant centers, and to provide transplant centers with a framework for evaluating and selecting candidates. In addition to addressing general considerations and providing disease specific recommendations for referral and listing, this updated consensus document includes an ethical framework, a recognition of the variability in acceptance of risk between transplant centers, and establishes a system to account for how a combination of risk factors may be taken into consideration in candidate selection for lung transplantation.

Catastrophic Mechanical Complications of Extracorporeal Membrane Oxygenation

Technical advances in extracorporeal membrane oxygenation (ECMO) have increased the number of cases that maintain longer duration. Long-term use of ECMO results in ECMO-related complications. Anticipation of the life-threatening mechanical complications and their management are critical for safe ECMO. In this study, we analyzed the incidence, nature, and risk factors of life-threatening mechanical complications during ECMO support. Furthermore, we presented our bedside algorithms to manage catastrophic ECMO complications. Data from 549 patients who underwent ECMO between December 2008 and December 2018 were retrospectively analyzed. The incidence of all life-threatening mechanical complications was 4.0%. Accidental decannulation (1.3%) was most common, followed by abrupt falling circuit flows (1.1%), pump failure (1.1%), circuit rupture (0.4%), and air in circuit (0.2%). Most (90.9%) of life-threatening events required circuit and cannula change, while 9.1% required vein collapse relief procedure. There was no death related to the event; however, six (27.3%) died during ECMO due to the underlying disease for which ECMO was required, and three (13.6%) died after weaning from ECMO. Multivariate regression analysis showed that awake ECMO and long-term ECMO support were significantly associated with life-threatening mechanical complications (p < 0.01). Our algorithm safely managed catastrophic ECMO problems without event-related deaths.

Hospital survival outcomes in acute respiratory distress syndrome patients receiving veno-venous extracorporeal membrane oxygenation for longer than 28 days: A retrospective study

The successful use of prolonged (ie, >28 days) veno-venous extracorporeal membrane oxygenation (V-V ECMO) is being increasingly reported. However, limited data are available on its outcomes. This study investigated the outcomes of acute respiratory distress syndrome (ARDS) patients on prolonged ECMO support. We retrospectively evaluated 57 patients requiring V-V ECMO for ARDS between 2015 and 2020. The patients were divided into two groups according to ECMO duration: (a) ≤28 days group (n = 43, 75%) or (b) >28 days (n = 14, 25%) group. Clinical characteristics, complications, and outcomes between these two groups were statistically compared. There were no significant differences in demographics, comorbidity, ARDS etiology, and severity scores between the two groups. However, the mechanical ventilation period before ECMO initiation was significantly longer in the >28 days group than in the ≤28 days group (10.5 days vs. 1 day; P < .05). The incidence of positive bacterial blood culture results during ECMO was significantly higher in the >28 days group than in the ≤28 days group (43% vs. 9%; P < .05). Additionally, the hospital survival rate was significantly lower in the >28 days group than in the ≤28 days ECMO group (21% vs. 60%; P < .05). Prolonged ECMO was associated with worse hospital survival outcomes. Early initiation of ECMO along with meticulous care and appropriate treatment against infection during ECMO could improve the hospital survival of ARDS patients on prolonged ECMO support.

Contraindications to the Initiation of Veno-Venous ECMO for Severe Acute Respiratory Failure in Adults: A Systematic Review and Practical Approach Based on the Current Literature

(1) Background: Extracorporeal membrane oxygenation (ECMO) is increasingly used for acute respiratory failure with few absolute but many relative contraindications. The provider in charge often has a difficult time weighing indications and contraindications to anticipate if the patient will benefit from this treatment, a decision that often decides life and death for the patient. To assist in this process in coming to a good evidence-based decision, we reviewed the available literature. (2) Methods: We performed a systematic review through a literature search of the MEDLINE database of former and current absolute and relative contraindications to the initiation of ECMO treatment. (3) Results: The following relative and absolute contraindications were identified in the literature: absolute-refusal of the use of extracorporeal techniques by the patient, advanced stage of cancer, fatal intracerebral hemorrhage/cerebral herniation/intractable intracranial hypertension, irreversible destruction of the lung parenchyma without the possibility of transplantation, and contraindications to lung transplantation; relative-advanced age, immunosuppressed patients/pharmacological immunosuppression, injurious ventilator settings > 7 days, right-heart failure, hematologic malignancies, especially bone marrow transplantation and graft-versus-host disease, SAPS II score ≥ 60 points, SOFA score > 12 points, PRESERVE score ≥ 5 points, RESP score ≤ -2 points, PRESET score ≥ 6 points, and "do not attempt resuscitation" order (DN(A)R status). (4) Conclusions: We provide a simple-to-follow algorithm that incorporates absolute and relative contraindications to the initiation of ECMO treatment. This algorithm attempts to weigh pros and cons regarding the benefit for an individual patient and hopefully assists caregivers to make better, informed decisions.

Perception of prolonged extracorporeal membrane oxygenation in Europe: an EuroELSO survey

The substantial increase in the number of patients receiving extracorporeal membrane oxygenation over the last decade has led to an evolution of indications and an expansion into wider patient groups. One of the unanticipated benefits of the increase in extracorporeal membrane oxygenation has been a change in the understanding of the natural history of many respiratory diseases. Development in technology and materials, reduced extracorporeal membrane oxygenation-specific complications, and improvement of critical care, in general, have facilitated longer extracorporeal membrane oxygenation runs, and the definition of prolonged extracorporeal membrane oxygenation was recently expanded to continuous support for more than 28 days. This survey aimed to describe European ECMO centers' perception and arbitrary definition of prolonged extracorporeal membrane oxygenation, patient management, and futility. Of 94 center responses, 37% regarded 14-21 days, 30% 21-28 days, and 28% >28 days as prolonged treatment. Bridge to recovery (64%) or to transplantation (20%) was the most common causes. Awake, and ambulation while on extracorporeal membrane oxygenation was reported from 34% of the centers. In case of perceived futility, decision to withdraw was taken in 65% of the centers in agreement between profession and family and in 30% by profession only. One-fourth of the centers did not discontinue support. Large differences prevail among European ECMO centers concerning local perception and patient management in prolonged extracorporeal membrane oxygenation.

Beyond Frontiers: Feasibility and Outcomes of Prolonged Veno-Venous Extracorporeal Membrane Oxygenation in Severe Acute Respiratory Distress Syndrome

Extracorporeal membrane oxygenation (ECMO) use in acute respiratory failure is increasing. We aim to compare characteristics and outcomes of patients with prolonged (≥21 days) veno-venous (VV) ECMO runs (pECMO), to patients with short (<21 days) VV ECMO runs (sECMO). The observational retrospective single-center study compared patients who received VV ECMO from January 2018 to June 2019 at Prince Mohamed Bin Abdulaziz Center in Riyadh, Saudi Arabia. Forty-three patients were supported with VV ECMO during the study period, of whom 37 are included as six patients were still receiving ECMO at time of data collection: 24 sECMO and 13 pECMO patients. Baseline characteristics and comorbidities were similar except pECMO patients were older and had a lower P/F ratio (61 [58-68] vs. 71[58-85.5], p = 0.05). Survival to hospital discharge (69% vs. 83%, p = 0.32; pECMO vs. sECMO) and 90 day survival (62% vs. 75%, p = 0.413; pECMO vs. sECMO) were similar among groups. At 1 year follow-up, all patients were still alive and independently functioning except for one patient in the pECMO group who required a walking aid related to trauma. In this single-center study, patients requiring pECMO had similar short- and long-term survival to those requiring sECMO duration.

ECMO in COVID-19-prolonged therapy needed? A retrospective analysis of outcome and prognostic factors

BACKGROUND

The role of venovenous extracorporeal membrane oxygenation (VV ECMO) in patients with COVID-19-induced acute respiratory distress syndrome (ARDS) still remains unclear. Our aim was to investigate the clinical course and outcome of those patients and to identify factors associated with the need for prolonged ECMO therapy.

METHODS

A retrospective single-center study on patients with VV ECMO for COVID-19-associated ARDS was performed. Baseline characteristics, ventilatory and ECMO parameters, and laboratory and virological results were evaluated over time. Six months follow-up was assessed.

RESULTS

Eleven of 16 patients (68.8%) survived to 6 months follow-up with four patients requiring short-term (<28 days) and seven requiring prolonged (⩾28 days) ECMO support. Lung compliance before ECMO was higher in the prolonged than in the short-term group (28.1 (28.8-32.1) ml/cmH₂O vs 18.7 (17.7-25.0) ml/cmH₂O, p = 0.030). Mechanical ventilation before ECMO was longer (19 (16-23) days vs 5 (5-9) days, p = 0.002) and SOFA score was higher (12.0 (10.5-17.0) vs 10.0 (9.0-10.0), p = 0.002) in non-survivors compared to survivors. Low viral load during the first days on ECMO tended to indicate worse outcomes. Seroconversion against SARS-CoV-2 occurred in all patients, but did not affect outcome.

CONCLUSIONS

VV ECMO support for COVID-19-induced ARDS is justified if initiated early and at an experienced ECMO center. Prolonged ECMO therapy might be required in those patients. Although no relevant predictive factors for the duration of ECMO support were found, the decision to stop therapy should not be made dependent of the length of ECMO treatment.

ECMO in COVID-19-prolonged therapy needed? A retrospective analysis of outcome and prognostic factors

Background:

The role of venovenous extracorporeal membrane oxygenation (VV ECMO) in patients with COVID-19-induced acute respiratory distress syndrome (ARDS) still remains unclear. Our aim was to investigate the clinical course and outcome of those patients and to identify factors associated with the need for prolonged ECMO therapy.

Methods:

A retrospective single-center study on patients with VV ECMO for COVID-19-associated ARDS was performed. Baseline characteristics, ventilatory and ECMO parameters, and laboratory and virological results were evaluated over time. Six months follow-up was assessed.

Results:

Eleven of 16 patients (68.8%) survived to 6 months follow-up with four patients requiring short-term (<28 days) and seven requiring prolonged (⩾28 days) ECMO support. Lung compliance before ECMO was higher in the prolonged than in the short-term group (28.1 (28.8–32.1) ml/cmH₂O vs 18.7 (17.7–25.0) ml/cmH₂O, p = 0.030). Mechanical ventilation before ECMO was longer (19 (16–23) days vs 5 (5–9) days, p = 0.002) and SOFA score was higher (12.0 (10.5–17.0) vs 10.0 (9.0–10.0), p = 0.002) in non-survivors compared to survivors. Low viral load during the first days on ECMO tended to indicate worse outcomes. Seroconversion against SARS-CoV-2 occurred in all patients, but did not affect outcome.

Conclusions:

VV ECMO support for COVID-19-induced ARDS is justified if initiated early and at an experienced ECMO center. Prolonged ECMO therapy might be required in those patients. Although no relevant predictive factors for the duration of ECMO support were found, the decision to stop therapy should not be made dependent of the length of ECMO treatment.

The Prolonged Use of VV ECMO Support in COVID-19: A Case Report

COVID-19 has resulted in unprecedented global health and economic challenges. The reported mortality in patients with COVID-19 requiring mechanical ventilation is high. VV ECMO may serve as a lifesaving rescue therapy for a minority of patients with COVID-19; however, its impact on overall survival of these patients is unknown. To date, few reports describe successful discharge from ECMO in COVID-19 after a prolonged ECMO run. The only Australian case of a COVID-19 patient, supported by prolonged VV ECMO in conjunction with prone ventilation, complicated by significant airway bleeding, and successfully decannulated after forty-two days, is described. VV ECMO is a resource-intense form of respiratory support. Providing complex therapies such as VV ECMO during a pandemic has its unique challenges. This case report provides a unique insight into the potential clinical sequelae of COVID-19, supported in an intensive care environment which was not resource-limited at the time, and adds to the evolving experience of prolonged VV ECMO support for ARDS with a goal to lung recovery.

Recovery from Total Acute Lung Failure After 20 Months of Extracorporeal Life Support

Since the first successful case report in 1972, extracorporeal life support or extracorporeal membrane oxygenation (ECMO) has become a standard approach for severe respiratory failure unresponsive to other therapy. In the past, if there was no recovery by approximately 30 days or if right ventricular heart failure occurred, ECMO was discontinued and the patient died. More recently patients with severe lung disease have been maintained for months, as opposed to days, with eventual decannulation and recovery. We report the case of a child, 7 years old, with severe inhalational burn injury and rapid progression to multisystem organ failure. She was supported by ECMO with no lung function for almost 2 years. Central nervous system function remained normal and lung function recovered. This is the longest successful case of ECMO to date and prompts further discussion regarding "irreversible" lung injury.

Purified β-glucans from the Shiitake mushroom ameliorates antibiotic-resistant Klebsiella pneumoniae-induced pulmonary sepsis

Bacterial infection remains the main cause of acute respiratory distress syndrome and is a leading cause of death and disability in critically ill patients. Here we report on the use of purified β-glucan (lentinan) extracts from Lentinus edodes (Shiitake) mushroom that can reduce infection by a multidrug-resistant clinical isolate of Klebsiella pneumoniae in a rodent pneumonia model, likely through immunomodulation. Adult male Sprague-Dawley rats were subjected to intra-tracheal administration of K. pneumoniae to induce pulmonary sepsis and randomized to three groups; vehicle control (Vehicle, n = 12), commercial lentinan (CL, n = 8) or in-house extracted lentinan (IHL, n = 8) were administered intravenously 1 h postinfection. Physiological parameters and blood gas analysis were measured, bacterial counts from bronchoalveolar-lavage (BAL) were determined, along with differential staining of white cells and measurement of protein concentration in BAL 48 h after pneumonia induction. Use of IHL extract significantly decreased BAL CFU counts. Both CL and IHL extractions reduced protein concentration in BAL. Use of IHL resulted in an improvement in physiological parameters compared to controls and CL. In conclusion, administration of lentinan to treat sepsis-induced lung injury appears safe and effective and may exert its effects in an immunomodulatory manner.

Utilization of Veno-Arterial Extracorporeal Life Support for Acute Respiratory Distress Syndrome After Liver Transplant

In this report, we present a case of successful long-term salvage of a patient with transfusion-related acute lung injury associated with acute respiratory distress syndrome immediately after a liver transplant. The patient was a 29-year-old man with end-stage liver disease due to sclerosing cholangitis who underwent liver transplant. After organ reperfusion, there was evidence of liver congestion, acidosis, coagulopathy, and acute kidney injury. He received 61 units of blood products. Continuous renal replacement therapy was initiated intraoperatively. On arrival to the intensive care unit, the patient was on high-dose pressors, and the patient developed respiratory failure and was immediately placed on veno-arterial extracorporeal membrane oxygenation via open femoral exposure. The patient presented with severe coagulopathy and early allograft dysfunction; therefore, no systemic heparin was administered and no thrombotic events occurred. He required extracorporeal membrane oxygenation support until posttransplant day 4, when resolution of the respiratory and cardiac dysfunction was noted. At 2 years after liver transplant, the patient has normal liver function, normal cognitive function, and stage V chronic kidney disease. We conclude that extracorporeal membrane oxygenation is a valuable therapeutic approach in patients with cardiorespiratory failure after liver transplant.

Mesenchymal Stem/Stromal Cells Therapy for Sepsis and Acute Respiratory Distress Syndrome

Sepsis and acute respiratory distress syndrome (ARDS) constitute devastating conditions with high morbidity and mortality. Sepsis results from abnormal host immune response, with evidence for both pro- and anti-inflammatory activation present from the earliest phases. The "proinflammatory" response predominates initially causing host injury, with later-phase sepsis characterized by immune cell hypofunction and opportunistic superinfection. ARDS is characterized by inflammation and disruption of the alveolar-capillary membrane leading to injury and lung dysfunction. Sepsis is the most common cause of ARDS. Approximately 20% of deaths worldwide in 2017 were due to sepsis, while ARDS occurs in over 10% of all intensive care unit patients and results in a mortality of 30 to 45%. Given the fact that sepsis and ARDS share some-but not all-underlying pathophysiologic injury mechanisms, the lack of specific therapies, and their frequent coexistence in the critically ill, it makes sense to consider therapies for both conditions together. In this article, we will focus on the therapeutic potential of mesenchymal stem/stromal cells (MSCs). MSCs are available from several tissues, including bone marrow, umbilical cord, and adipose tissue. Allogeneic administration is feasible, an important advantage for acute conditions like sepsis or ARDS. They possess diverse mechanisms of action of relevance to sepsis and ARDS, including direct and indirect antibacterial actions, potent effects on the innate and adaptive response, and pro-reparative effects. MSCs can be preactivated thereby potentiating their effects, while the use of their extracellular vesicles can avoid whole cell administration. While early-phase clinical trials suggest safety, considerable challenges exist in moving forward to phase III efficacy studies, and to implementation as a therapy should they prove effective.

Physiology of Extracorporeal Gas Exchange

Circulating venous blood outside the body, through an artificial lung (membrane oxygenator), and returning oxygenated blood to the patient is extracorporeal gas exchange. Oxygen and carbon dioxide exchange in a membrane lung is controlled by regulating blood flow, blood composition, and device design. With this control, lung function can be replaced for weeks by artificial organs. © 2020 American Physiological Society. Compr Physiol 10:879-891, 2020.

Extracorporeal membrane oxygenation support in adult patients with acute respiratory distress syndrome

Introduction: The global number of patients receiving extracorporeal membrane oxygenation (ECMO) support has been growing after several studies highlighted the favorable results attained in cases of severe respiratory failure. However, evidence-based guidelines for optimal use of ECMO are lacking.Areas covered: This review covers optimal candidates, timing of initiation, strategies for patient management including mechanical ventilation, and decision-making regarding discontinuation of ECMO based on its potential role in treatment of patients with acute respiratory distress syndrome.Expert opinion: Early initiation of ECMO should be considered if hypoxemia and uncompensated hypercapnia do not respond to optimal conventional treatment. Use of a comprehensive management approach for preventing additional lung injury and extrapulmonary organ failure is critical during ECMO support to ensure the best outcome. The possibility of weaning from ECMO should be fully assessed by a multidisciplinary team during ECMO support. Futility should not be determined solely by duration of ECMO, and use of prolonged ECMO for lung recovery may be worthwhile.

Ethical challenges of adult ECMO

The use of extracorporeal membrane oxygenation (ECMO) is expanding rapidly, and as more centres streamline their management policies, the bioethics literature on ECMO has been highlighting the ethical challenges of using an expensive, resource-intensive technology including its eligibility, duration of support, cost-effectiveness and societal repercussions. The absence of high-quality studies on long-term outcomes of ECMO survivors leads to multiple ethical problems involving patient autonomy, beneficence and clinical wisdom pertaining to its initiation, maintenance and termination. This article reviews some of the ethical challenges that affect decision-making during ECMO therapy and suggests an ethical framework that may help the treating team deal with such conundrums, when the patient does not recover despite being on ECMO.

Spontaneous breathing in patients with severe acute respiratory distress syndrome receiving prolonged extracorporeal membrane oxygenation

Background

The use of extracorporeal membrane oxygenation (ECMO) in awake, spontaneously breathing and non-intubated patients (awake ECMO) may be a novel therapeutic strategy for severe acute respiratory distress syndrome (ARDS) patients. The purpose of this study is to assess the feasibility and safety of awake ECMO in severe ARDS patients receiving prolonged ECMO (> 14 days).

Methods

We describe our experience with 12 consecutive severe ARDS patients (age, 39.1 ± 16.4 years) supported with awake ECMO to wait for native lung recovery during prolonged ECMO treatment from July 2013 to January 2018. Outcomes are reported including the hospital mortality, ECMO-related complications and physiological data on weaning from invasive ventilation.

Results

The patients received median 26.0 (15.5, 64.8) days of total ECMO duration in the cohort. The longest ECMO support duration was 121 days. Awake ECMO and extubation was implemented after median 10.2(5.0, 42.9) days of ECMO. Awake ECMO was not associated with increased morbidity. The total invasive ventilation duration, lengths of stay in the ICU and hospital in the cohort were 14.0(12.0, 37.3) days, 33.0(22.3, 56.5) days and 46.5(27.3, 84.8) days, respectively. The hospital mortality rate was 33.3% (4/12) in the cohort. Survivors had more stable respiratory rate and heart rate after extubation when compared to the non-survivors.

Conclusions

With carefully selected patients, awake ECMO is a feasible and safe strategy for severe pulmonary ARDS patients receiving prolonged ECMO support to wait for native lung recovery.

Veno-venous extracorporeal life support for blastomycosis-associated acute respiratory distress syndrome

BACKGROUND

Blastomyces is a dimorphic fungus endemic to regions of North America, which can lead to pneumonia and fatal severe acute respiratory diseases syndrome in up to 89% of patients. Extracorporeal life support can provide adequate oxygenation while allowing the lungs to rest and heal, which might be an ideal therapy in this patient group, although long-term clinical and radiological outcomes are not known.

CLINICAL FEATURES

We report on five consecutive patients admitted to Toronto General Hospital intensive care unit between January 2012 and September 2016, with progressive respiratory failure requiring veno-venous extracorporeal life support within 24-96 hours following mechanical ventilation. Ultra-lung protective mechanical ventilation was achieved within 24 hours. Recovery was the initial goal in all patients. Extracorporeal life support was provided for a prolonged period (up to 49 days), and four patients were successfully discharged from the intensive care unit. Long-term radiological assessment in three patients showed major improvement within 2 years of follow-up with some persistent disease-related changes (bronchiectasis, fibrosis, and cystic changes). In two patients, long-term functional and neuropsychological outcomes showed similar limitations to what is seen in acute respiratory distress syndrome patients who are not supported with extracorporeal life support and in acute respiratory distress syndrome patients without blastomycosis, but worse pulmonary function outcomes in the form of obstructive and restrictive changes that correlated with the radiological imaging.

CONCLUSION

Veno-venous extracorporeal life support can effectively provide prolonged support for patients with blastomycosis-associated acute respiratory distress syndrome that is safe and associated with favorable long-term outcomes.

Clinical outcomes of patients receiving prolonged extracorporeal membrane oxygenation for respiratory support

BACKGROUND

There are limited data regarding prolonged extracorporeal membrane oxygenation (ECMO) support, despite increase in ECMO use and duration in patients with respiratory failure. The objective of this study was to investigate the outcomes of severe acute respiratory failure patients supported with prolonged ECMO for more than 28 days.

METHODS

Between January 2012 and December 2015, all consecutive adult patients with severe acute respiratory failure who underwent ECMO for respiratory support at 16 tertiary or university-affiliated hospitals in South Korea were enrolled retrospectively. The patients were divided into two groups: short-term group defined as ECMO for ⩽28 days and long-term group defined as ECMO for more than 28 days. In-hospital and 6-month mortalities were compared between the two groups.

RESULTS

A total of 487 patients received ECMO support for acute respiratory failure during the study period, and the median support duration was 8 days (4-20 days). Of these patients, 411 (84.4%) received ECMO support for ⩽28 days (short-term group), and 76 (15.6%) received support for more than 28 days (long-term group). The proportion of acute exacerbation of interstitial lung disease as a cause of respiratory failure was higher in the long-term group than in the short-term group (22.4% versus 7.5%, p < 0.001), and the duration of mechanical ventilation before ECMO was longer (4 days versus 1 day, p < 0.001). The hospital mortality rate (60.8% versus 69.7%, p = 0.141) and the 6-month mortality rate (66.2% versus 74.0%, p = 0.196) were not different between the two groups. ECMO support longer than 28 days was not associated with hospital mortality in univariable and multivariable analyses.

CONCLUSIONS

Short- and long-term survival rates among patients receiving ECMO support for more than 28 days for severe acute respiratory failure were not worse than those among patients receiving ECMO for 28 days or less.

Assessment of 1-year Outcomes in Survivors of Severe Acute Respiratory Distress Syndrome Receiving Extracorporeal Membrane Oxygenation or Mechanical Ventilation: A Prospective Observational Study

Background:

Little is known about the long-term outcomes of severe acute respiratory distress syndrome (ARDS) patients requiring extracorporeal membrane oxygenation (ECMO). This study aimed to investigate the 1-year outcomes of these patients or patients receiving mechanical ventilation (MV) and compare their health-related quality of life (HRQoL) to the general population.

Methods:

Severe ARDS survivors admitted to two ICUs in China between January 2012 and January 2014 were enrolled. Of the severe ARDS survivors enrolled, 1-year postdischarge, HRQoL assessment using the Short-Form 36 (SF-36) and EuroQol questionnaire dimensions, 6-min walking distance, chest computed tomography scan, pulmonary function, and arterial blood gas analysis were compared for ARDS patients with or without ECMO.

Results:

ARDS patients receiving ECMO had a significantly higher Acute Physiology and Chronic Health Evaluation II score (30.3 ± 6.7 vs. 26.5 ± 7.3, P = 0.036), lung injury score (3.3 ± 0.4 vs. 2.8 ± 0.5, P = 0.000), Sequential Organ Failure Assessment score (10.8 ± 3.5 vs. 7.9 ± 3.1, P = 0.000), lower PaO₂/FiO₂ ratio ([mmHg, 1 mmHg = 0.133 kPa], 68.3 ± 16.1 vs. 84.8 ± 16.5, P = 0.000), and increased extrapulmonary organ failure (2 [1, 3] vs. 1 [1, 1], P = 0.025) compared with patients not receiving ECMO. ECMO and non-ECMO survivors showed similar pulmonary function, morphological abnormalities, resting arterial blood gas values, and 6-min walking distance. Mild pulmonary dysfunction and abnormal morphology were observed in a few survivors. In addition, ECMO and non-ECMO survivors showed a similar quality of life. ECMO survivors showed lower SF-36 physical functioning and role-physical domain scores (minimum clinically significant difference at least 5 points), and non-ECMO survivors had similar outcome.

Conclusions:

One-year posthospital discharge, severe ARDS survivors receiving ECMO or MV demonstrated comparable outcomes. Compared with the general population, ARDS survivors showed reduced HRQoL. Pulmonary function and lung morphology revealed sufficient recovery with minor lung impairment.

Selection of Patients for Initial Clinical Trials of Solid Organ Xenotransplantation

Several groups have reported extended survival of genetically engineered pig organs in nonhuman primates, varying from almost 10 months for life-supporting kidney grafts and more than 2 years for non-life-supporting heart grafts to less than 1 month for life-supporting liver and lung grafts. We have attempted to define groups of patients who may not have an option to wait for an allograft. These include kidney, heart, and lung candidates who are highly-allosensitized. In addition, some kidney candidates (who have previously lost at least 2 allografts from rapid recurrence of native kidney disease) have a high risk of further recurrence and will not be offered a repeat allotransplant. Patients with complex congenital heart disease, who may have undergone previous palliative surgical procedures, may be unsuitable for ventricular assist device implantation. Patients dying of fulminant hepatic failure, for whom no alternative therapy is available, may be candidates for a pig liver, even if only as a bridge until an allograft becomes available. When the results of pig organ xenotransplantation in nonhuman primates suggest a realistic potential for success of a pilot clinical trial, highly selected patients should be offered participation.

Extracorporeal membrane oxygenation (ECMO) as a treatment strategy for severe acute respiratory distress syndrome (ARDS) in the low tidal volume era: A systematic review

OBJECTIVE

To evaluate the hospital survival in patients with severe ARDS managed with ECMO and low tidal volume ventilation as compared to patients managed with low tidal volume ventilation alone.

METHODS

Electronic databases were searched for studies of at least 10 adult patients with severe ARDS comparing the use of ECMO with low tidal volume ventilation to mechanical ventilation with a low tidal volume alone. Only studies reporting hospital or ICU survival were included. All identified studies were assessed independently by two reviewers.

RESULTS

Of 1782 citations, 27 studies (n=1674) met inclusion criteria. Hospital survival for ECMO patients ranged from 33.3 to 86%, while survival with conventional therapy ranged from 36.3 to 71.2%. Five studies were identified with appropriate control groups allowing comparison, but due to the high degree of variability between studies (I²=63%), their results could not be pooled. Two of these studies demonstrated a significant difference, both favouring ECMO over conventional therapy.

CONCLUSION

Given the lack of studies with appropriate control groups, our confidence in a difference in outcome between the two therapies remains weak. Future studies on the use of ECMO for severe ARDS are needed to clarify the role of ECMO in this disease.

Brain injury during venovenous extracorporeal membrane oxygenation

PURPOSE

The frequency of neurological events and their impact on patients receiving venovenous extracorporeal membrane oxygenation (VV-ECMO) are unknown. We therefore study the epidemiology, risk factors, and impact of cerebral complications occurring in VV-ECMO patients.

METHODS

Observational study conducted in a tertiary referral center (2006-2012) on patients developing a neurological complication (ischemic stroke or intracranial bleeding) while on VV-ECMO versus those who did not, and a systematic review on this topic.

RESULTS

Among 135 consecutive patients who had received VV-ECMO, 18 (15 assessable) developed cerebral complications on ECMO: cerebral bleeding in 10 (7.5 %), ischemic stroke in 3 (2 %), or diffuse microbleeds in 2 (2 %), occurring after respective medians (IQR) of 3 (1-11), 21 (10-26), and 36 (8-63) days post-ECMO onset. Intracranial bleeding was independently associated with renal failure at intensive care unit admission and rapid PaCO2 decrease at ECMO initiation, but not with age, comorbidities, or hemostasis disorders. Seven (70 %) patients with intracranial bleeding and one (33 %) with ischemic stroke died versus 40 % of patients without neurological event. A systematic review found comparable intracranial bleeding rates (5 %).

CONCLUSIONS

Neurological events occurred frequently in patients on VV-ECMO. Intracranial bleeding, the most frequent, occurred early and was associated with higher mortality. Because it was independently associated with rapid hypercapnia decrease, the latter should be avoided at ECMO onset, but its exact role remains to be determined. These findings may have major implications for the care of patients requiring VV-ECMO.