Survival benefit of extracorporeal membrane oxygenation in severe COVID-19: a multi-centre-matched cohort study

Response on Rapid Review to Inform Policy Guidance on Welsh Respiratory ECMO Provision

Internationally, extracorporeal membrane oxygenation (ECMO) is now a core and standard organ support tool to provide tertiary critical care and cardiac services within a network of hospitals and a key tool for running an effective and efficient cardio-respiratory pathways. The letter aims to put the spotlight on some of the missing clinical evidence on respiratory ECMO and including them will help to arrive at a better-informed national ECMO policy decision.

Veno-venous extracorporeal membrane oxygenation for severe COVID-19 associated acute respiratory distress syndrome: A retrospective, nationwide, Danish cohort study

BACKGROUND

Severe acute respiratory syndrome (ARDS) may require veno-venous extracorporeal membrane oxygenation (V-V ECMO). The aim of this study was to provide data on patient selection and outcome in a nationwide cohort study of patients with COVID-19 associated ARDS supported with V-V ECMO.

METHODS

We identified all patients with COVID-19, who were supported with V-V ECMO in Denmark from March 10, 2020, to December 31, 2021, and retrieved data on patients who were referred to- and accepted for ECMO, demographics, outcome data, and complications. Risk factors for mortality were analysed using multivariate Cox regression analysis.

RESULTS

During the study period, 1836 patients were admitted to Danish intensive care units (ICUs). In the same period, there were 197 enquiries for ECMO of whom 118 patients were considered eligible. Overall, 71 patients were cannulated for ECMO; three patients were cannulated for veno-arterial extracorporeal membrane oxygenation (V-A ECMO) due to right sided heart failure and 68 patients were cannulated for V-V ECMO. Two patients accepted for V-V ECMO died during cannulation. The median age was 55 years (IQR 45-60) and 66% were males. The median duration of ECMO support was 13 days (IQR 7-21), mechanical ventilation median 26 days (IQR 14-42), ICU stay median 34 days (IQR 17-46), and length of hospital stay median 41 days (IQR 25-56). Ninety-day mortality was 43%. Age of 60 years or more was associated with an increased risk of mortality. Pre-existing hypertension was associated with a decreased risk of mortality.

CONCLUSION

A nationwide, Danish cohort study of 68 COVID-19 patients supported with V-V ECMO, showed a 90-day survival of 43%, which is in accordance with reports from comparable cohorts. Age of 60 years or more was associated with an increased risk of mortality. Pre-existing hypertension was associated with a decreased risk of mortality.

Characteristics of the top 100 cited original studies on extracorporeal membrane oxygenation: a bibliometric analysis

Background

Extracorporeal membrane oxygenation (ECMO) has been widely used as a life support for different kinds of acute cardiopulmonary dysfunction. The present study aimed at presenting the global trend of the top 100 cited original studies related to ECMO.

Methods

Bibliometric analysis was the primary methodology for this study. Literature data were collected from Web of Science Core Collection (WoSCC). Indicators were analyzed and visualized by Excel and VOSviewer, the study design, study population, study topic, journal impact factor (IF), Category Rank and Category Quartile, author, country, journal and keywords were included.

Results

The top 100 cited articles were published between 1979 and 2021. With 19 publications, 2020 was the most prolific year. High-income countries or regions, such as the United States of America (USA), France and Canada owned a majority of the articles. Seventeen studies were randomized trials, 52 were finished in single center, and 53 focused on adults. The 100 articles were documented by 31 different journals. The journals were well recognized, with a mean IF2022 of 28.77, a median of 8.8, and a range of 1.6-168.9. The major diseases were viral infection of respiratory system, acute respiratory distress syndrome (ARDS) or respiratory failure, pulmonary hypertension of infants, heart failure/cardiogenic shock, diaphragmatic hernia and cardiac arrest. Specifically, coronavirus disease 2019 (COVID-19) accounted for 72.7% of viral infections. The disease spectrum changed from congenital cardiopulmonary dysfunction to cardiac arrest, ARDS and cardiopulmonary failure, and to severe COVID infection cases. Another fresh hotspot is immune dysfunction.

Conclusions

This bibliometric analysis identified 100 most frequently cited original studies on ECMO and described their characteristics, which may help with further investigations.

Mapping a Decade (2014-2024) of Research on Extracorporeal Membrane Oxygenation for Acute Respiratory Distress Syndrome: A Visual Analysis with CiteSpace and VOSviewer

Background

Acute Respiratory Distress Syndrome (ARDS) stands as a primary cause of mortality among critically ill patients. Extracorporeal Membrane Oxygenation (ECMO) is increasingly employed in the rescue therapy of ARDS patients. However, the current status of research in the field of ECMO-assisted ARDS remains unclear.

Objective

This research aims to categorize and evaluate the literature regarding Extracorporeal Membrane Oxygenation (ECMO) support for Acute Respiratory Distress Syndrome (ARDS), offering a comprehensive analysis of bibliometric properties, research hotspots, and developmental trends within the domain of ECMO-assisted ARDS.

Methods

A literature search was conducted for ECMO-assisted support for patients with ARDS in the Web of Science Core Collection (WoSCC) database from 2014 to 2024. We employed visualization tools such as CiteSpace and VOSviewer to explore and assess connections among nations, institutions, researchers, and co-cited journals, authors, references, and keywords.

Results

This study included 1739 publications. The United States leads in publication volume with Columbia University at the forefront of ECMO research. Intensive Care Medicine has been identified as the most cited journal in this field. Alain Combes from France stands out as a key contributor, particularly in his 2018 publication in the New England Journal of Medicine, which is the most cited work in the discipline. Furthermore, keyword analysis identified three distinct research phases: examining complications associated with ECMO therapy, exploring optimal strategies for mechanical ventilation under ECMO support, and compiling insights into the application of ECMO in treating COVID-19 patients and in the development of predictive models for patient outcomes.

Conclusion

Using bibliometric visualization techniques, this study revealed significant progress in the use of ECMO for treating ARDS respiratory support, evaluated the impact of these findings, and outlined potential areas for future studies.

Obesity associated with improved mortality of extracorporeal membrane oxygenation for severe COVID-19 pneumonia

INTRODUCTION

Determining a patient's candidacy for extracorporeal membrane oxygenation (ECMO) in severe COVID-19 pneumonia is a critical aspect of efficient healthcare delivery. A body mass index (BMI) ≥40 is considered a relative contraindication for ECMO by the Extracorporeal Life Support Organization (ELSO). We sought to determine the impact of obesity on the survival of patients with COVID-19 on ECMO.

METHODS

This project was a retrospective review of a multicenter US database from January 2020 to December 2021. The primary outcome was in-hospital mortality after ECMO initiation, with a comparison between patients classified into body mass index categories (<30, 30-39.9, and ≥40). Secondary outcomes included ventilator days, intensive care days, and complications.

RESULTS

We completed records review on 359 patients, with 90 patients excluded because of missing data. The overall mortality for the 269 patients was 37.5%. Patients with a BMI <30 had higher odds of mortality compared to all patients with BMI >30 (OR 1.98; p = 0.013), those with BMI 30-39.9 (OR 1.84; p = 0.036), and BMI ≥40 (OR 2.33; p = 0.024). There were no differences between BMI groups for ECMO duration; length of stay (LOS); or rate of bloodstream infection, stroke, or blood transfusion. Age, ECMO duration, and modified-Elixhauser index were not independent risk factors for mortality.

CONCLUSIONS

In patients receiving ECMO for severe COVID-19, neither obesity (BMI >30) nor morbid obesity (BMI >40) were associated with in-hospital mortality. These results are consistent with previous reports and held true after adjusting for age and comorbidities. Our data suggest further examination of the recommendations to withhold ECMO in patients who are obese.

Venovenous extracorporeal membrane oxygenation for COVID-19 associated severe respiratory failure: Case series from a Hungarian tertiary centre

INTRODUCTION

Venovenous extracorporeal membrane oxygenation (V-V ECMO) is recommended for the support of patients with severe COVID-19 associated severe respiratory failure (SRF). We report the characteristics and outcome of COVID-19 patients supported with V-V ECMO in a Hungarian centre.

METHODS

We retrospectively collected data on all patients admitted with proven SARS CoV-2 infection who received V-V ECMO support between March 2021 and May 2022.

RESULTS

Eighteen patients were placed on ECMO during this period, (5 women, age (mean ± SD) 44 ± 10 years, APACHE II score (median (interquartile range)) 12 (10-14.5)). Before ECMO support, they had been hospitalised for 6 (4-11) days. Fifteen patients received noninvasive ventilation for 4 (2-8) days, two patients had high flow nasal oxygen therapy, for one day each. They had already been intubated for 2.5 (1-6) days. Prone position was applied in 15 cases. On the day before ECMO initiation the Lung Injury Score was 3.25 (3-3.26), the PaO2/FiO2 ratio was 71 ± 19 mmHg. The duration of V-V ECMO support was 26 ± 20 days, and the longest run lasted 70 days. Patients were mechanically ventilated for 34 ± 23 days. The intensive care unit (ICU) and the hospital length of stay were 40 ± 28 days and 45 ± 31 days, respectively. Eleven patients were successfully weaned from ECMO. The ICU survival rate was 56%, the in-hospital survival was 50%. All patients who were discharged from hospital reported a good health-related quality of life Rankin score (0-2) at the 5-16 months follow-up.

CONCLUSIONS

During the last three waves of the COVID-19 pandemic, we achieved a 56% ICU and a 50% hospital survival rate at our low volume centre.

Survival and Long-Term Functional Status of COVID-19 Patients Requiring Prolonged Extracorporeal Membrane Oxygenation Support

Rationale: Severe cases of acute respiratory distress syndrome (ARDS) may require prolonged (>28 d) extracorporeal membrane oxygenation (ECMO). In nonresolving disease, recovery is uncertain, and lung transplant may be proposed. Objectives: This study aims to identify the variables influencing survival and to describe the functional status of these patients at 6 months. Methods: This was a retrospective, multicenter, observational cohort study including patients requiring ECMO support for coronavirus disease (COVID-19)-related ARDS for >28 days. Multivariate analysis was performed using Cox regression in preselected variables and in least absolute shrinkage and selection operator selected variables. In a post hoc analysis to account for confounders and differences in awake strategy use by centers, treatment effects of the awake strategy were estimated using an augmented inverse probability weighting estimator with robust standard errors clustered by center. Results: Between March 15, 2020 and March 15, 2021, 120 patients required ECMO for >28 days. Sixty-four patients (53.3%) survived decannulation, 62 (51.7%) were alive at hospital discharge, and 61 (50.8%) were alive at 6-month follow-up. In the multivariate analysis, age (1.09; 95% confidence interval [CI], 1.03-1.15; P = 0.002) and an awake ECMO strategy (defined as the patient being awake, cooperative, and performing rehabilitation and physiotherapy with or without invasive mechanical ventilation at any time during the extracorporeal support) (0.14; 95% CI, 0.03-0.47; P = 0.003) were found to be predictors of hospital survival. At 6 months, 51 (42.5%) patients were at home, 42 (84.3%) of them without oxygen therapy. A cutoff point of 47 ECMO days had a 100% (95% CI, 76.8-100%) sensitivity and 60% (95% CI, 44.3-73.6%) specificity for oxygen therapy at 6 months, with 100% specificity being found in 97 days. Conclusions: Patients with COVID-19 who require ECMO for >28 days can survive with nonlimiting lung impairment. Age and an awake ECMO strategy may be associated with survival. Longer duration of support correlates with need for oxygen therapy at 6 months.

Veno-arterial extracorporeal membrane oxygenation for circulatory failure in COVID-19 patients: insights from the ECMOSARS registry

OBJECTIVES

The clinical profile and outcomes of patients with Coronavirus Disease 2019 (COVID-19) who require veno-arterial extracorporeal membrane oxygenation (VA-ECMO) or veno-arterial-venous extracorporeal membrane oxygenation (VAV-ECMO) are poorly understood. We aimed to describe the characteristics and outcomes of these patients and to identify predictors of both favourable and unfavourable outcomes.

METHODS

ECMOSARS is a multicentre, prospective, nationwide French registry enrolling patients who require veno-venous extracorporeal membrane oxygenation (ECMO)/VA-ECMO in the context of COVID-19 infection (652 patients at 41 centres). We focused on 47 patients supported with VA- or VAV-ECMO for refractory cardiogenic shock.

RESULTS

The median age was 49. Fourteen percent of patients had a prior diagnosis of heart failure. The most common aetiologies of cardiogenic shock were acute pulmonary embolism (30%), myocarditis (28%) and acute coronary syndrome (4%). Extracorporeal cardiopulmonary resuscitation (E-CPR) occurred in 38%. In-hospital survival was 28% in the whole cohort, and 43% when E-CPR patients were excluded. ECMO cannulation was associated with significant improvements in pH and FiO2 on day 1, but non-survivors showed significantly more severe acidosis and higher FiO2 than survivors at this point (P = 0.030 and P = 0.006). Other factors associated with death were greater age (P = 0.02), higher body mass index (P = 0.03), E-CPR (P = 0.001), non-myocarditis aetiology (P = 0.02), higher serum lactates (P = 0.004), epinephrine (but not noradrenaline) use before initiation of ECMO (P = 0.003), haemorrhagic complications (P = 0.001), greater transfusion requirements (P = 0.001) and more severe Survival after Veno-Arterial ECMO (SAVE) and Sonographic Assessment of Intravascular Fluid Estimate (SAFE) scores (P = 0.01 and P = 0.03).

CONCLUSIONS

We report the largest focused analysis of VA- and VAV-ECMO recipients in COVID-19. Although relatively rare, the need for temporary mechanical circulatory support in these patients is associated with poor prognosis. However, VA-ECMO remains a viable solution to rescue carefully selected patients. We identified factors associated with poor prognosis and suggest that E-CPR is not a reasonable indication for VA-ECMO in this population.

Validation of extracorporeal membrane oxygenation mortality prediction and severity of illness scores in an international COVID-19 cohort

BACKGROUND

Veno-venous extracorporeal membrane oxygenation (V-V ECMO) is a lifesaving support modality for severe respiratory failure, but its resource-intensive nature led to significant controversy surrounding its use during the COVID-19 pandemic. We report the performance of several ECMO mortality prediction and severity of illness scores at discriminating survival in a large COVID-19 V-V ECMO cohort.

METHODS

We validated ECMOnet, PRESET (PREdiction of Survival on ECMO Therapy-Score), Roch, SOFA (Sequential Organ Failure Assessment), APACHE II (acute physiology and chronic health evaluation), 4C (Coronavirus Clinical Characterisation Consortium), and CURB-65 (Confusion, Urea nitrogen, Respiratory Rate, Blood Pressure, age >65 years) scores on the ISARIC (International Severe Acute Respiratory and emerging Infection Consortium) database. We report discrimination via Area Under the Receiver Operative Curve (AUROC) and Area under the Precision Recall Curve (AURPC) and calibration via Brier score.

RESULTS

We included 1147 patients and scores were calculated on patients with sufficient variables. ECMO mortality scores had AUROC (0.58-0.62), AUPRC (0.62-0.74), and Brier score (0.286-0.303). Roch score had the highest accuracy (AUROC 0.62), precision (AUPRC 0.74) yet worst calibration (Brier score of 0.3) despite being calculated on the fewest patients (144). Severity of illness scores had AUROC (0.52-0.57), AURPC (0.59-0.64), and Brier Score (0.265-0.471). APACHE II had the highest accuracy (AUROC 0.58), precision (AUPRC 0.64), and best calibration (Brier score 0.26).

CONCLUSION

Within a large international multicenter COVID-19 cohort, the evaluated ECMO mortality prediction and severity of illness scores demonstrated inconsistent discrimination and calibration highlighting the need for better clinically applicable decision support tools.

Comparison of Sedation and Analgesia Requirements in Patients With SARS-CoV-2 Versus Non-SARS-CoV-2 Acute Respiratory Distress Syndrome on Veno-Venous ECMO

BACKGROUND

Increased analgosedation requirements have been described in patients with acute respiratory distress syndrome (ARDS) on extracorporeal membrane oxygenation (ECMO) support due to unique pharmacokinetic challenges. There is a paucity of data comparing sedation requirements in patients on ECMO for ARDS secondary to SARS-CoV-2 versus other etiologies of respiratory failure.

OBJECTIVE

To compare sedation and analgesia requirements in adult patients with SARS-CoV-2 versus non-SARS-CoV-2 ARDS requiring veno-venous (VV) ECMO support.

METHODS

We performed a retrospective cohort study of adult patients receiving sedation and analgesia on VV-ECMO support. Patients were excluded if cannulated at an outside hospital for greater than 24 hours, expired within 48 hours of ECMO cannulation, or received neuromuscular blocking agents for greater than 7 consecutive days following ECMO cannulation.

RESULTS

We evaluated 108 patients on VV-ECMO support, including 44 with non-SARS-CoV-2 ARDS and 64 with SARS-CoV-2 ARDS. The median daily dexmedetomidine requirements were significantly higher in the SARS-CoV-2 cohort (16.7 vs 13.4 mcg/kg/day, P = 0.03), while the median propofol daily requirements were significantly higher in the non-SARS-CoV-2 cohort (40.3 vs 53.5 mg/kg/day, P < 0.01). There was no difference in daily requirements of opioids, benzodiazepines, and ketamine between groups. Use of adjunct agents to facilitate weaning was significantly higher in the SARS-CoV-2 cohort (78.1% vs 43.2%, P < 0.01).

CONCLUSION AND RELEVANCE

Patients with ARDS on VV-ECMO support require multiple analgosedative agents with concomitant use of nonparenteral adjunct agents. Further studies are needed to evaluate optimal analgosedation strategies in patients on ECMO support.

Validation of extracorporeal membrane oxygenation mortality prediction and severity of illness scores in an international COVID‐19 cohort

Background

Veno‐venous extracorporeal membrane oxygenation (V‐V ECMO) is a lifesaving support modality for severe respiratory failure, but its resource‐intensive nature led to significant controversy surrounding its use during the COVID‐19 pandemic. We report the performance of several ECMO mortality prediction and severity of illness scores at discriminating survival in a large COVID‐19 V‐V ECMO cohort.

Methods

We validated ECMOnet, PRESET (PREdiction of Survival on ECMO Therapy‐Score), Roch, SOFA (Sequential Organ Failure Assessment), APACHE II (acute physiology and chronic health evaluation), 4C (Coronavirus Clinical Characterisation Consortium), and CURB‐65 (Confusion, Urea nitrogen, Respiratory Rate, Blood Pressure, age >65 years) scores on the ISARIC (International Severe Acute Respiratory and emerging Infection Consortium) database. We report discrimination via Area Under the Receiver Operative Curve (AUROC) and Area under the Precision Recall Curve (AURPC) and calibration via Brier score.

Results

We included 1147 patients and scores were calculated on patients with sufficient variables. ECMO mortality scores had AUROC (0.58–0.62), AUPRC (0.62–0.74), and Brier score (0.286–0.303). Roch score had the highest accuracy (AUROC 0.62), precision (AUPRC 0.74) yet worst calibration (Brier score of 0.3) despite being calculated on the fewest patients (144). Severity of illness scores had AUROC (0.52–0.57), AURPC (0.59–0.64), and Brier Score (0.265–0.471). APACHE II had the highest accuracy (AUROC 0.58), precision (AUPRC 0.64), and best calibration (Brier score 0.26).

Conclusion

Within a large international multicenter COVID‐19 cohort, the evaluated ECMO mortality prediction and severity of illness scores demonstrated inconsistent discrimination and calibration highlighting the need for better clinically applicable decision support tools.

Extracorporeal Membrane Oxygenation for Acute Respiratory Failure Due to COVID-19: A Multicenter Matched Cohort Study

Mechanical ventilation for respiratory failure due to COVID-19 is associated with significant morbidity and mortality. Veno-venous extracorporeal membrane oxygenation (ECMO) is an attractive management option. This study sought to determine the effect of ECMO on hospital mortality and discharge condition in this population. We conducted a retrospective multicenter study to emulate a pragmatic targeted trial comparing ECMO to mechanical ventilation without ECMO for severe COVID-19. Data were gathered from a large hospital network database in the US. Adults admitted with COVID-19 were included if they were managed with ECMO or mechanical ventilation for severe hypoxemia and excluded if they had significant comorbidities or lacked functional independence on admission. The groups underwent coarsened exact matching on multiple clinical variables. The primary outcome was adjusted in-hospital mortality; secondary outcomes included ventilator days, intensive care days, and discharge destination. A total of 278 ECMO patients were matched to 2,054 comparison patients. Adjusted in-hospital mortality was significantly less in the ECMO group (38.8% vs. 60.1%, p < 0.001). Extracorporeal membrane oxygenation was associated with higher rates of liberation from mechanical ventilation, intensive care discharge, and favorable discharge destination. These findings support the use of ECMO for well-selected patients with severe acute respiratory failure due to COVID-19.

A Comparison of Long-Term Outcomes in Patients Managed With Venovenous Extracorporeal Membrane Oxygenation in the First and Second Waves of the COVID-19 Pandemic in the United Kingdom

OBJECTIVES

Early studies of venovenous extracorporeal membrane oxygenation (ECMO) in COVID-19 have revealed similar outcomes to historical cohorts. Changes in the disease and treatments have led to differences in the patients supported on venovenous ECMO in the first and second waves. We aimed to compare these two groups in both the acute and follow-up phase.

DESIGN

Retrospective single-center cohort study comparing mortality at censoring date (November 30, 2021) and decannulation, patient characteristics, complications and lung function and quality of life (QOL-by European Quality of Life 5 Dimensions 3 Level Version) at first follow-up in patients supported on venovenous ECMO between wave 1 and wave 2 of the COVID-19 pandemic.

SETTING

Critical care department of a severe acute respiratory failure service.

PATIENTS

Patients supported on ECMO for COVID-19 between wave 1 (March 17, 2020, to August 31, 2020) and wave 2 (January 9, 2020, to May 25, 2021).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One hundred twenty-three patients were included in our analysis. Survival at censoring date (χ 2 , 6.35; p = 0.012) and decannulation (90.4% vs 70.0%; p < 0.001) was significantly lower in the second wave, while duration of ECMO run was longer (12.0 d [18.0-30.0 d] vs 29.5 d [15.5-58.3 d]; p = 0.005). Wave 2 patients had longer application of noninvasive ventilation (NIV) prior to ECMO and a higher frequency of barotrauma. Patient age and NIV use were independently associated with increased mortality (odds ratio 1.07 [1.01-1.14]; p = 0.025 and 3.37 [1.12-12.60]; p = 0.043, respectively). QOL and lung function apart from transfer coefficient of carbon monoxide corrected for hemoglobin was similar at follow-up across the waves.

CONCLUSIONS

Most patients with COVID-19 supported on ECMO in both waves survived in the short and longer term. At follow-up patients had similar lung function and QOL across the two waves. This suggests that ECMO has an ongoing role in the management of a carefully selected group of patients with COVID-19.

Outcome of Emergency Pulmonary Lobectomy under ECMO Support in Patients with COVID-19

BACKGROUND

 Not much is known about the results of nonelective anatomical lung resections in coronavirus disease 2019 (COVID-19) patients put on extracorporeal membrane oxygenation (ECMO). The aim of this study was to analyze the outcome of lobectomy under ECMO support in patients with acute respiratory failure due to severe COVID-19.

METHODS

 All COVID-19 patients undergoing anatomical lung resection with ECMO support at a German university hospital were included into a prospective database. Study period was April 1, 2020, to April 30, 2021 (first, second, and third waves in Germany).

RESULTS

 A total of nine patients (median age 61 years, interquartile range 10 years) were included. There was virtually no preexisting comorbidity (median Charlson score of comorbidity 0.2). The mean interval between first positive COVID-19 test and surgery was 21.9 days. Clinical symptoms at the time of surgery were sepsis (nine of nine), respiratory failure (nine of nine), acute renal failure (five of nine), pleural empyema (five of nine), lung artery embolism (four of nine), and pneumothorax (two of nine). Mean intensive care unit (ICU) and ECMO days before surgery were 15.4 and 6, respectively. Indications for surgery were bacterial superinfection with lung abscess formation and progressive septic shock (seven of nine) and abscess formation with massive pulmonary hemorrhage into the abscess cavity (two of nine). All patients were under venovenous ECMO with femoral-jugular configuration. Operative procedures were lobectomy (eight) and pneumonectomy (one). Weaning from ECMO was successful in four of nine. In-hospital mortality was five of nine. Mean total ECMO days were 10.3 ± 6.2 and mean total ICU days were 27.7 ± 9.9. Mean length of stay was 28.7 ± 8.8 days.

CONCLUSION

 Emergency surgery under ECMO support seems to open up a perspective for surgical source control in COVID-19 patients with bacterial superinfection and localized pulmonary abscess.

Extracorporeal membrane oxygenation for COVID-19-associated acute respiratory distress syndrome: A nationwide analysis

Extracorporeal membrane oxygenation (ECMO) has been used for COVID-19-associated acute respiratory distress syndrome (ARDS). We aimed to elucidate the association between ECMO and mortality in patients with COVID-19-associated ARDS in the nationwide setting. United States National Inpatient Sample was used to identify mechanically ventilated adults for COVID-19 with ARDS. We divided them into three groups according to the use of ECMO (i.e., no-ECMO, venovenous [VV]-ECMO, and venoarterial [VA]-ECMO). The primary outcome was in-hospital mortality, while the secondary outcomes included the length of hospital stay (LOS) and the total costs during hospitalization. We performed a stepwise logistic regression, adjusting for baseline characteristics, comorbidities, and severity. We included 68 795 (mean age [SD]: 63.5 [0.1]), 3280 (mean age [SD]: 48.7 [0.5]), and 340 (mean age [SD]: 43.3 [2.1]) patients who received no-, VV-, and VA-ECMO, respectively. The logistic regression analysis did not show significant associations between the use of VV-/VA-ECMO and mortality (adjusted odds ratio with no-ECMO as reference [95% confidence interval]: 1.03 [0.86-1.24] and 1.18 [0.64-2.15], respectively). While LOS was longest with VV-ECMO, the total costs were highest with VA-ECMO. In conclusion, our study found no association between the use of ECMO and mortality of COVID-19-associated ARDS in the nationwide setting.

ESICM guidelines on acute respiratory distress syndrome: definition, phenotyping and respiratory support strategies

The aim of these guidelines is to update the 2017 clinical practice guideline (CPG) of the European Society of Intensive Care Medicine (ESICM). The scope of this CPG is limited to adult patients and to non-pharmacological respiratory support strategies across different aspects of acute respiratory distress syndrome (ARDS), including ARDS due to coronavirus disease 2019 (COVID-19). These guidelines were formulated by an international panel of clinical experts, one methodologist and patients' representatives on behalf of the ESICM. The review was conducted in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement recommendations. We followed the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to assess the certainty of evidence and grade recommendations and the quality of reporting of each study based on the EQUATOR (Enhancing the QUAlity and Transparency Of health Research) network guidelines. The CPG addressed 21 questions and formulates 21 recommendations on the following domains: (1) definition; (2) phenotyping, and respiratory support strategies including (3) high-flow nasal cannula oxygen (HFNO); (4) non-invasive ventilation (NIV); (5) tidal volume setting; (6) positive end-expiratory pressure (PEEP) and recruitment maneuvers (RM); (7) prone positioning; (8) neuromuscular blockade, and (9) extracorporeal life support (ECLS). In addition, the CPG includes expert opinion on clinical practice and identifies the areas of future research.

Extracorporeal membrane oxygenation for COVID-19 and influenza associated acute respiratory distress syndrome: a systematic review

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has been used extensively for H1N1 influenza and coronavirus disease 2019 (COVID-19)-related acute respiratory distress syndrome (ARDS) to improve gas exchange and quickly correct hypoxemia and hypercapnia. This systematic review summarized the evidence on ECMO for the treatment of COVID-19 and influenza-associated ARDS.

RESEARCH DESIGN AND METHODS

This is a systematic review and meta-analysis of studies to compare the efficacy and safety of ECMO with conventional mechanical ventilation in adults with COVID-19 and influenza-associated ARDS. The study performed a structured search on PubMed, Embase, Web of Science, Scopus and The Cochrane Library. The primary outcome was hospital mortality.

RESULTS

The study included 15 observational studies with 5239 patients with COVID-19 and influenza-associated ARDS. The use of ECMO significantly reduced in-hospital mortality in COVID-19-associated ARDS (OR = 0.40; 95% CI = 0.27-0.58; P < 0.00001) but did not reduce influenza-related mortality (OR = 1.08; 95% CI = 0.41-2.87; P = 0.87). Moreover, ECMO treatment meaningfully increased the incidence of bleeding complications (OR = 7.66; 95% CI = 2.47-23.72; P = 0.0004).

CONCLUSION

The use of ECMO significantly reduced in-hospital mortality in COVID-19- associated ARDS, which may be related to the advances in ECMO-related techniques and the increased experience of clinicians. However, the incidence of bleeding complications remains high. [Figure: see text].

Prone Positioning in Mechanically Ventilated COVID-19 Patients: Timing of Initiation and Outcomes

The COVID-19 pandemic led to a broad implementation of proning to enhance oxygenation in both self-ventilating and mechanically ventilated critically ill patients with acute severe hypoxic respiratory failure. However, there is little data on the impact of the timing of the initiation of prone positioning in COVID-19 patients receiving mechanical ventilation. In this study, we analyzed our proning practices in mechanically ventilated COVID-19 patients. There were 931 total proning episodes in 144 patients, with a median duration of 16 h (IQR 15-17 h) per proning cycle. 563 proning cycles were initiated within 7 days of intubation (early), 235 within 7-14 days (intermediate), and 133 after 14 days (late). The mean change in oxygenation defined as the delta PaO₂/FiO₂ ratio (ΔPF) after the prone episode was 16.6 ± 34.4 mmHg (p < 0.001). For early, intermediate, and late cycles, mean ΔPF ratios were 18.5 ± 36.7 mmHg, 13.2 ± 30.4 mmHg, and 14.8 ± 30.5 mmHg, with no significant difference in response between early, intermediate, and late proning (p = 0.2), respectively. Our findings indicate a favorable oxygenation response to proning episodes at all time points, even after >14 days of intubation. However, the findings cannot be translated directly into a survival advantage, and more research is needed in this area.

Extracorporeal Membrane Oxygenation to Support COVID-19 Patients: A Propensity-Matched Cohort Study

Background

In patients with severe respiratory failure from COVID-19, extracorporeal membrane oxygenation (ECMO) treatment can facilitate lung-protective ventilation and may improve outcome and survival if conventional therapy fails to assure adequate oxygenation and ventilation. We aimed to perform a confirmatory propensity-matched cohort study comparing the impact of ECMO and maximum invasive mechanical ventilation alone (MVA) on mortality and complications in severe COVID-19 pneumonia.

Materials and Methods

All 295 consecutive adult patients with confirmed COVID-19 pneumonia admitted to the intensive care unit (ICU) from March 13^th, 2020, to July 31^st, 2021 were included. At admission, all patients were classified into 3 categories: (1) full code including the initiation of ECMO therapy (AAA code), (2) full code excluding ECMO (AA code), and (3) do-not-intubate (A code). For the 271 non-ECMO patients, match eligibility was determined for all patients with the AAA code treated with MVA. Propensity score matching was performed using a logistic regression model including the following variables: gender, P/F ratio, SOFA score at admission, and date of ICU admission. The primary endpoint was ICU mortality.

Results

A total of 24 ECMO patients were propensity matched to an equal number of MVA patients. ICU mortality was significantly higher in the ECMO arm (45.8%) compared with the MVA cohort (16.67%) (OR 4.23 (1.11, 16.17); p=0.02). Three-month mortality was 50% with ECMO compared to 16.67% after MVA (OR 5.91 (1.55, 22.58); p < 0.01). Applied peak inspiratory pressures (33.42 ± 8.52 vs. 24.74 ± 4.86 mmHg; p < 0.01) and maximal PEEP levels (14.47 ± 3.22 vs. 13.52 ± 3.86 mmHg; p=0.01) were higher with MVA. ICU length of stay (LOS) and hospital LOS were comparable in both groups.

Conclusion

ECMO therapy may be associated with an up to a three-fold increase in ICU mortality and 3-month mortality compared to MVA despite the facilitation of lung-protective ventilation settings in mechanically ventilated COVID-19 patients. We cannot confirm the positive results of the first propensity-matched cohort study on this topic. This trial is registered with NCT05158816.

New and personalized ventilatory strategies in patients with COVID-19

Coronavirus disease (COVID-19) is caused by the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) virus and may lead to severe respiratory failure and the need for mechanical ventilation (MV). At hospital admission, patients can present with severe hypoxemia and dyspnea requiring increasingly aggressive MV strategies according to the clinical severity: noninvasive respiratory support (NRS), MV, and the use of rescue strategies such as extracorporeal membrane oxygenation (ECMO). Among NRS strategies, new tools have been adopted for critically ill patients, with advantages and disadvantages that need to be further elucidated. Advances in the field of lung imaging have allowed better understanding of the disease, not only the pathophysiology of COVID-19 but also the consequences of ventilatory strategies. In cases of refractory hypoxemia, the use of ECMO has been advocated and knowledge on handling and how to personalize strategies have increased during the pandemic. The aims of the present review are to: (1) discuss the evidence on different devices and strategies under NRS; (2) discuss new and personalized management under MV based on the pathophysiology of COVID-19; and (3) contextualize the use of rescue strategies such as ECMO in critically ill patients with COVID-19.

Multi-horizon predictive models for guiding extracorporeal resource allocation in critically ill COVID-19 patients

OBJECTIVE

Extracorporeal membrane oxygenation (ECMO) resource allocation tools are currently lacking. We developed machine learning (ML) models for predicting COVID-19 patients at risk of receiving ECMO to guide patient triage and resource allocation.

MATERIAL AND METHODS

We included COVID-19 patients admitted to intensive care units for >24 h from March 2020 to October 2021, divided into training and testing development and testing-only holdout cohorts. We developed ECMO deployment timely prediction model ForecastECMO using Gradient Boosting Tree (GBT), with pre-ECMO prediction horizons from 0 to 48 h, compared to PaO2/FiO2 ratio, Sequential Organ Failure Assessment score, PREdiction of Survival on ECMO Therapy score, logistic regression, and 30 pre-selected clinical variables GBT Clinical GBT models, with area under the receiver operator curve (AUROC) and precision recall curve (AUPRC) metrics.

RESULTS

ECMO prevalence was 2.89% and 1.73% in development and holdout cohorts. ForecastECMO had the best performance in both cohorts. At the 18-h prediction horizon, a potentially clinically actionable pre-ECMO window, ForecastECMO, had the highest AUROC (0.94 and 0.95) and AUPRC (0.54 and 0.37) in development and holdout cohorts in identifying ECMO patients without data 18 h prior to ECMO.

DISCUSSION AND CONCLUSIONS

We developed a multi-horizon model, ForecastECMO, with high performance in identifying patients receiving ECMO at various prediction horizons. This model has potential to be used as early alert tool to guide ECMO resource allocation for COVID-19 patients. Future prospective multicenter validation would provide evidence for generalizability and real-world application of such models to improve patient outcomes.

Mechanical power of ventilation and driving pressure: two undervalued parameters for pre extracorporeal membrane oxygenation ventilation and during daily management?

The current ARDS guidelines highly recommend lung protective ventilation which include plateau pressure (P_plat < 30 cm H₂O), positive end expiratory pressure (PEEP > 5 cm H₂O) and tidal volume (V_t of 6 ml/kg) of predicted body weight. In contrast, the ELSO guidelines suggest the evaluation of an indication of veno-venous extracorporeal membrane oxygenation (ECMO) due to hypoxemic or hypercapnic respiratory failure or as bridge to lung transplantation. Finally, these recommendations remain a wide range of scope of interpretation. However, particularly patients with moderate-severe to severe ARDS might benefit from strict adherence to lung protective ventilation strategies. Subsequently, we discuss whether extended physiological ventilation parameter analysis might be relevant for indication of ECMO support and can be implemented during the daily routine evaluation of ARDS patients. Particularly, this viewpoint focus on driving pressure and mechanical power.

The effect of therapeutic plasma exchange therapy on veno-venous ECMO weaning success in severe COVID-19 ARDS patients

INTRODUCTION

Primarily, this study aimed to investigate the effect of TPE (therapeutic plasma exchange) treatment on successful ECMO weaning in severe COVID-19 ARDS patients treated with V-V ECMO.

METHODS

The study was applied retrospectively on patients over the age of 18 who were hospitalized in the ICU between January 1, 2020 and March 1, 2022.

RESULTS

The study was performed on 33 patients, 36.3% (n: 12) of whom received TPE treatment. The rate of successful ECMO weaning was statistically higher in the TPE treatment group (without TPE: 14.3% [n: 3], with TPE: 50% [n: 6], p = 0.044). The 1-month mortality was also statistically lower in the TPE treatment group (p = 0.044). In the logistic analysis, It was found that the risk of unsuccessful ECMO weaning increased 6 times in those who did not receive TPE treatment (OR; 6.0, 95% CI; 1.134-31.735, p = 0.035).

CONCLUSION

TPE treatment may increase the success rate of V-V ECMO weaning in severe COVID-19 ARDS patients treated with V-V ECMO.

Extracorporeal Membrane Oxygenation for COVID-19: Comparison of Outcomes to Non-COVID-19-Related Viral Acute Respiratory Distress Syndrome From the Extracorporeal Life Support Organization Registry

To compare complications and mortality between patients that required extracorporeal membrane oxygenation (ECMO) support for acute respiratory distress syndrome (ARDS) due to COVID-19 and non-COVID-19 viral pathogens.

DESIGN

Retrospective observational cohort study.

SETTING

Adult patients in the Extracorporeal Life Support Organization registry.

PATIENTS

Nine-thousand two-hundred ninety-one patients that required ECMO for viral mediated ARDS between January 2017 and December 2021.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcomes of interest were mortality during ECMO support and prior to hospital discharge. Time-to-event analysis and logistic regression were used to compare outcomes between the groups. Among 9,291 included patients, 1,155 required ECMO for non-COVID-19 viral ARDS and 8,136 required ECMO for ARDS due to COVID-19. Patients with COVID-19 had longer duration of ECMO (19.6 d [interquartile range (IQR), 10.1-34.0 d] vs 10.7 d [IQR, 6.3-19.7 d]; p < 0.001), higher mortality during ECMO support (44.4% vs 27.5%; p < 0.001), and higher in-hospital mortality (50.2% vs 34.5%; p < 0.001). Further, patients with COVID-19 were more likely to experience mechanical and clinical complications (membrane lung failure, pneumothorax, intracranial hemorrhage, and superimposed infection). After adjusting for pre-ECMO disease severity, patients with COVID-19 were more than two times as likely to die in the hospital compared with patients with non-COVID-19 viral ARDS.

CONCLUSIONS

Patients with COVID-19 that require ECMO have longer duration of ECMO, more complications, and higher in-hospital mortality compared with patients with non-COVID-19-related viral ARDS. Further study in patients with COVID-19 is critical to identify the patient phenotype most likely to benefit from ECMO and to better define the role of ECMO in the management of this disease process.

Techniques for Oxygenation and Ventilation in Coronavirus Disease 2019

This paper discusses mechanisms of hypoxemia and interventions to oxygenate critically ill patients with COVID-19 which range from nasal cannula to noninvasive and mechanical ventilation. Noninvasive ventilation includes continuous positive airway pressure ventilation (CPAP) and high-flow nasal cannula (HFNC) with or without proning. The evidence for each of these modalities is discussed and thereafter, when to transition to mechanical ventilation (MV). Various techniques of MV, again with and without proning, and rescue strategies which would include extra corporeal membrane oxygenation (ECMO) when it is available and permissive hypoxemia where it is not, are discussed.

Massive Airway Hemorrhage in Severe COVID-19 and the Role of Endotracheal Tube Clamping

Background

Venovenous extracorporeal membrane oxygenation (VV-ECMO) has been widely used in treating patients with coronavirus disease 2019 (COVID-19) with severe respiratory failure. However, there are few reports of the successful treatment of patients with massive airway hemorrhage in severe COVID-19 during VV-ECMO treatment.

Methods

We analyzed the treatment process of a patient with a massive airway hemorrhage in severe COVID-19, who underwent prolonged VV-ECMO treatment.

Results

A 59-year-old female patient was admitted to the intensive care unit after being confirmed to have severe acute respiratory syndrome coronavirus 2 infection with severe acute respiratory distress syndrome. VV-ECMO, mechanical ventilation, and prone ventilation were administered. Major airway hemorrhage occurred on day 14 of ECMO treatment; conventional management was ineffective. We provided complete VV-ECMO support, discontinued anticoagulation, disconnected the ventilator, clipped the tracheal intubation, and intervened to embolize the descending bronchial arteries. After the airway hemorrhage stopped, we administered cryotherapy under bronchoscopy, low-dose urokinase locally, and bronchoalveolar lavage in the airway to clear the blood clots. The patient's condition gradually improved; she underwent ECMO weaning and decannulation after 88 days of VV-ECMO treatment, and the membrane oxygenator was changed out four times. She was successfully discharged after 182 days in hospital.

Conclusion

Massive airway hemorrhage in patients with severe COVID-19 and treated with ECMO is catastrophic. It is feasible to clamp the tracheal tube with the full support of ECMO. Notably, bronchoscopy with cryotherapy is effective for removing blood clots.

Long-term outcomes in patients who received veno-venous extracorporeal membrane oxygenation and renal replacement therapy: a retrospective cohort study

Background

Acute kidney injury (AKI) is a frequent complication in patients with severe respiratory failure receiving extracorporeal membrane oxygenation (ECMO). However, little is known of long-term kidney function in ECMO survivors. We aimed to assess the long-term mortality and kidney outcomes in adult patients treated with veno-venous ECMO (VV-ECMO).

Methods

This was a single-centre retrospective study of adult patients (≥ 18 years old) who were treated with VV-ECMO at a commissioned ECMO centre in the UK between 1st September 2010, and 30th November 2016. AKI was defined and staged using the serum creatinine and urine output criteria of the Kidney Diseases: Improving Global Outcomes (KDIGO) classification. The primary outcome was 1-year mortality. Secondary outcomes were long-term mortality (up to March 2020), 1-year incidence of end-stage kidney disease (ESKD) or chronic kidney disease (CKD) among AKI patients who received renal replacement therapy (AKI-RRT), AKI patients who did not receive RRT (AKI-no RRT) and patients without AKI (non-AKI).

Results

A total of 300 patients [57% male; median age 44.5; interquartile range (IQR) 34–54] were included in the final analysis. Past medical histories included diabetes (12%), hypertension (17%), and CKD (2.3%). The main cause of severe respiratory failure was pulmonary infection (72%). AKI occurred in 230 patients (76.7%) and 59.3% received renal replacement therapy (RRT). One-year mortality was 32% in AKI-RRT patients vs. 21.4% in non-AKI patients (p = 0.014). The median follow-up time was 4.35 years. Patients who received RRT had a higher risk of 1-year mortality than those who did not receive RRT (adjusted HR 1.80, 95% CI 1.06, 3.06; p = 0.029). ESKD occurred in 3 patients, all of whom were in the AKI-RRT group. At 1-year, 41.2% of survivors had serum creatinine results available. Among these, CKD was prevalent in 33.3% of AKI-RRT patients vs. 4.3% in non-AKI patients (p = 0.004).

Conclusions

VV-EMCO patients with AKI-RRT had high long-term mortality. Monitoring of kidney function after hospital discharge was poor. In patients with follow-up creatinine results available, the CKD prevalence was high at 1 year, especially in AKI-RRT patients. More awareness about this serious long-term complication and appropriate follow-up interventions are required.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01046-0.

The Use of ECMO for COVID-19: Lessons Learned

The coronavirus disease 2019 (COVID-19) pandemic has seen an increase in global cases of severe acute respiratory distress syndrome (ARDS), with a concomitant increased demand for extracorporeal membrane oxygenation (ECMO). Outcomes of patients with severe ARDS due to COVID-19 infection receiving ECMO support are evolving. The need for surge capacity, practical and ethical limitations on implementing ECMO, and the prolonged duration of ECMO support in patients with COVID-19-related ARDS has revealed limitations in organization and resource utilization. Coordination of efforts at multiple levels, from research to implementation, resulted in numerous innovations in the delivery of ECMO.

Outcomes of Extracorporeal Membrane Oxygenation in COVID-19-Induced Acute Respiratory Distress Syndrome: An Inverse Probability Weighted Analysis

Although venovenous extracorporeal membrane oxygenation (VV ECMO) has been used in case of COVID-19 induced acute respiratory distress syndrome (ARDS), outcomes and criteria for its application should be evaluated.

OBJECTIVES

To describe patient characteristics and outcomes in patients receiving VV ECMO due to COVID-19-induced ARDS and to assess the possible impact of COVID-19 on mortality.

DESIGN SETTING AND PARTICIPANTS

Multicenter retrospective study in 15 ICUs worldwide. All adult patients (> 18 yr) were included if they received VV ECMO with ARDS as main indication. Two groups were created: a COVID-19 cohort from March 2020 to December 2020 and a "control" non-COVID ARDS cohort from January 2018 to July 2019.

MAIN OUTCOMES AND MEASURES

Collected data consisted of patient demographics, baseline variables, ECMO characteristics, and patient outcomes. The primary outcome was 60-day mortality. Secondary outcomes included patient characteristics, COVID-19-related therapies before and during ECMO and complication rate. To assess the influence of COVID-19 on mortality, inverse probability weighted (IPW) analyses were used to correct for predefined confounding variables.

RESULTS

A total of 193 patients with COVID-19 received VV ECMO. The main indication for VV ECMO consisted of refractory hypoxemia, either isolated or combined with refractory hypercapnia. Complications with the highest occurrence rate included hemorrhage, an additional infectious event or acute kidney injury. Mortality was 35% and 45% at 28 and 60 days, respectively. Those mortality rates did not differ between the first and second waves of COVID-19 in 2020. Furthermore, 60-day mortality was equal between patients with COVID-19 and non-COVID-19-associated ARDS receiving VV ECMO (hazard ratio 60-d mortality, 1.27; 95% CI, 0.82-1.98; p = 0.30).

CONCLUSIONS AND RELEVANCE

Mortality for patients with COVID-19 who received VV ECMO was similar to that reported in other COVID-19 cohorts, although no differences were found between the first and second waves regarding mortality. In addition, after IPW, mortality was independent of the etiology of ARDS.

Extracorporeal membrane oxygenation in COVID-19 associated acute respiratory distress syndrome: A narrative review

Venovenous extracorporeal membrane oxygenation (VV-ECMO) is an established rescue therapy in the management of refractory acute respiratory distress syndrome (ARDS). Although ECMO played an important role in previous respiratory viral epidemics, concerns about the benefits and usefulness of this technique were raised during the coronavirus disease 2019 (COVID-19) pandemic. Indeed, the mortality rate initially reported in small case series from China was concerning and exceeded 90%. A few months later, the critical care community published the findings from several observational cohorts on the use of extracorporeal membrane oxygenation (ECMO) in COVID-19-related ARDS. Contrary to the preliminary results, data from the first surge supported the use of ECMO in experienced centers because the mortality rate was comparable to those from the ECMO to Rescue Lung Injury in Severe ARDS (EOLIA) trial or other large prospective studies. However, the mortality rate of the population with severe disease evolved during the pandemic, in conjunction with changes in the management of the disease and the occurrence of new variants. The results from subsequent studies confirmed that the outcomes mainly depend on strict patient selection and center expertise. In comparison with non-COVID-related ARDS, the duration of ECMO for COVID-related ARDS was longer and increased over time. Clinicians and decision-makers must integrate this finding in the ECMO decision-making process to plan their ICU capacity and resource allocation. This narrative review summarizes the current evidence and specific considerations for ECMO use in COVID-19-associated ARDS.

ARDS in the Time of Corona: Context and Perspective

For more than 2 years, COVID-19 has been holding the world at awe with new waves of infections, novel mutants, and still limited (albeit improved) means to combat SARS-CoV-2-induced respiratory failure, the most common and fatal presentation of severe COVID-19. In the present perspective, we draw from the successes and—mostly—failures in previous acute respiratory distress syndrome (ARDS) work and the experiences from COVID-19 to define conceptual barriers that have so far hindered therapeutic breakthroughs in this deadly disease, and to open up new avenues of thinking and thus, ultimately of therapy.

Krebs von den Lungen 6 (KL-6) levels in COVID-19 ICU patients are associated with mortality

BACKGROUND

Krebs von den Lungen 6 (KL-6) is a high-molecular-weight mucin-like glycoprotein, which is also known as MUC1. KL-6 is mainly produced by type 2 pneumocytes and bronchial epithelial cells, and, therefore, elevated circulating KL-6 levels may denote disorders of the alveolar epithelial lining. The objective of this study is to verify if KL-6 serum level might support ICU physicians in predicting mortality, risk stratifying and triaging severe COVID-19 patients.

METHODS

A retrospective cohort study, including all the COVID-19 patients who measured KL-6 serum values at least once during their ICU stay, was performed. The study sample, 122 patients, was divided in two groups, according to the median KL-6 value at ICU admission (median log-transformed KL-6 value: 6.73 U/ml; group A: KL-6 lower than the median and group B: KL-6 higher than the median).

RESULTS

One-hundred twenty-two ICU patients were included in this study. Mortality was higher in group B than in group A (80 versus 46%; p < 0.001); both linear and logistic multivariate analyses showed ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (P/F) significantly and inversely related to KL-6 values.

CONCLUSION

At ICU admission, KL-6 serum level was significantly higher in the most hypoxic COVID-19 patients and independently associated with ICU mortality.

Respiratory indications for ECMO: focus on COVID-19

Extracorporeal membrane oxygenation (ECMO) is increasingly being used for patients with severe respiratory failure and has received particular attention during the coronavirus disease 2019 (COVID-19) pandemic. Evidence from two key randomized controlled trials, a subsequent post hoc Bayesian analysis, and meta-analyses support the interpretation of a benefit of ECMO in combination with ultra-lung-protective ventilation for select patients with very severe forms of acute respiratory distress syndrome (ARDS). During the pandemic, new evidence has emerged helping to better define the role of ECMO for patients with COVID-19. Results from large cohorts suggest outcomes during the first wave of the pandemic were similar to those in non-COVID-19 cohorts. As the pandemic continued, mortality of patients supported with ECMO has increased. However, the precise reasons for this observation are unclear. Known risk factors for mortality in COVID-19 and non-COVID-19 patients are higher patient age, concomitant extra-pulmonary organ failures or malignancies, prolonged mechanical ventilation before ECMO, less experienced treatment teams and lower ECMO caseloads in the treating center. ECMO is a high resource-dependent support option; therefore, it should be used judiciously, and its availability may need to be constrained when resources are scarce. More evidence from high-quality research is required to better define the role and limitations of ECMO in patients with severe COVID-19.