Respiratory indications for ECMO: focus on COVID-19

Successful management of intracranial hemorrhage with brain herniation in a postpartum patient on extracorporeal membranous oxygenation: A case report

Managing intracranial hemorrhage in patients supported by extracorporeal oxygenation (ECMO) presents significant clinical challenges. We report a case of a postpartum patient with severe acute respiratory distress syndrome (ARDS) necessitating venovenous ECMO support, complicated by multicompartmental intracranial hemorrhage resulting in brain herniation and necessitating emergent medical and surgical management of refractory intracranial hypertension. Care was guided by multimodal neuromonitoring, including intracranial pressure monitoring and electroencephalography. Despite these challenges, the patient achieved excellent neurological recovery. This case underscores the intricacies of managing neurological complications during ECMO and highlights the potential benefits of comprehensive neuromonitoring strategies.

Risk factors for invasive mechanical ventilation, extracorporeal membrane oxygenation, and mortality in children with severe adenovirus infection in the pediatric intensive care unit: a retrospective study

BACKGROUND

Adenovirus infection causes considerable morbidity and mortality in pediatric patients, primarily those affected by severe respiratory system involvement. Although prevalent, it often presents vague indications, making accurate diagnosis and management challenging. This study aims to set some risk factors for invasive mechanical ventilation, ECMO, and mortality in children with severe adenovirus infection admitted to PICU.

METHODS

We evaluated 66 children with severe adenovirus infection admitted to the PICU of Children's Hospital, Zhejiang University School of Medicine, from 2018 to 2019. Data on general conditions, clinical manifestations, laboratory findings, pathogenetic and radiological discoveries, treatments, therapeutic efficacy, and outcomes were collected. Machine learning models were used to predict the need for invasive mechanical ventilation, ECMO, and mortality.

RESULTS

Of the 66 patients, 5 died, and 61 survived. Significant factors related to mortality included heart failure (p = 0.005), pericardial effusion (p = 0.032), septic shock (p = 0.009), hemoglobin levels (p = 0.013), lactate dehydrogenase (p = 0.022), albumin (p = 0.035), normal creatinine levels (p = 0.037), and pneumothorax (p = 0.002). Additional risk factors for invasive mechanical ventilation included acute respiratory distress syndrome and encephalopathy. Low breath sounds were identified as a risk factor for ECMO. For predicting poor outcomes, including invasive mechanical ventilation, ECMO, or mortality, the random forest model using these factors demonstrated high accuracy, with an area under the curve of 0.968.

CONCLUSIONS

The study indicates poor prognosis in children with severe adenovirus infection is significantly related to comorbidities and clinical symptoms. Machine learning models can accurately predict adverse outcomes, providing valuable insights for management and treatment. Identifying high-risk patients using these models can improve clinical outcomes by guiding timely and appropriate interventions.

TRIAL REGISTRATION

The article is a retrospective study without a clinical trial number, so it is not applicable.

In-hospital outcomes and 6-month follow-up results of patients supported with extracorporeal membrane oxygenation for COVID-19 from the second wave to the end of the pandemic (EuroECMO-COVID): a prospective, international, multicentre, observational study

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) for COVID-19 was thoroughly assessed during the first pandemic wave, but data on subsequent waves are limited. We aimed to investigate in-hospital and 6-month survival of patients with COVID-19 supported with ECMO from the second pandemic wave (Sept 15, 2020) until the end of the pandemic (March 21, 2023, announced by WHO).

METHODS

EuroECMO-COVID is a prospective, observational study including adults (aged ≥16 years) requiring ECMO respiratory support for COVID-19 from 98 centres in 21 countries. We compared patient characteristics and outcomes between in-hospital survivors and non-survivors. Mixed-effects multivariable logistic regressions were used to investigate factors linked to in-hospital mortality. 6-month survival and overall patient status were determined via patient contact or chart review. This study is registered with ClinicalTrials.gov, NCT04366921, and is complete.

FINDINGS

We included 3860 patients (2687 [69·7%] were male and 1169 [30·3%] were female; median age 51 years [SD 11]) from 98 centres in 21 countries. In-hospital mortality was 55·9% (n=2158), with 81·2% (n=1752) deaths occurring during ECMO support. More non-survivors had diabetes, hypertension, cardiovascular disease, and renal failure, and required more pre-ECMO inotropes and vasopressors compared with survivors. Median support duration was 18 days (IQR 10-31) for both groups. Factors linked to in-hospital mortality included older age, pre-ECMO renal failure, pre-ECMO vasopressors use, longer time from intubation to ECMO initiation, and complications, including neurological events, sepsis, bowel ischaemia, renal failure, and bleeding. Of the 1702 (44·1%) in-hospital survivors, 99·7% (n=1697) were alive at 6 months follow-up. Many patients at 6 months follow-up had dyspnoea (501 [32·0%] of 1568 patients), cardiac (122 [7·8%] of 1568 patients), or neurocognitive (168 [10·7%] of 1567 patients) symptoms.

INTERPRETATION

Our data for patients undergoing ECMO support for respiratory distress from the second COVID-19 wave onwards confirmed most findings from the first wave regarding patient characteristics and factors correlated to in-hospital mortality. Nevertheless, in-hospital mortality was higher than during the initial pandemic wave while 6-month post-discharge survival remained favourable (99·7%). Persisting post-discharge symptoms confirmed the need for post-ECMO patient follow-up programmes.

FUNDING

None.

The Effect of Extracorporeal Membrane Oxygenation on the Pharmacokinetics of Dexmedetomidine Hydrochloride

OBJECTIVES

Our objective was to explore the effects of extracorporeal membrane oxygenation (ECMO) on the pharmacokinetics of dexmedetomidine hydrochloride via vitro and in vivo experiments DESIGN: A single-center animal investigation.

SETTING

An experimental animal facility in a tertiary hospital.

PARTICIPANTS

Eighteen male Landrace pigs.

INTERVENTIONS

For the in vitro experiment, ECMO circuits were primed with whole blood solutions of dexmedetomidine at different concentrations and ran ex vivo. The adsorption rates of dexmedetomidine hydrochloride in ECMO circuits and control glass tubes were compared at 60 minutes, 5 hours, and 10 hours after the start of the in vitro experiment. In the in vivo experiment, 12 Landrace pigs were randomly allocated to the venovenous ECMO group or the control group. Dexmedetomidine hydrochloride (1 μg/kg) was administered to both groups. Blood samples were collected at 0 minutes, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 30 minutes, 45 minutes, 60 minutes, 90 minutes, 2 hours, 3 hours, 5 hours, 7 hours, and 10 hours after administration. The plasma concentrations of dexmedetomidine were measured, and pharmacokinetic analysis was conducted in both groups.

MEASUREMENTS AND MAIN RESULTS

The results revealed no significant difference in adsorption rates of dexmedetomidine hydrochloride in ECMO circuits at 60 minutes and 5 hours, but differences were observed at 10 hours. In vivo experiment, pharmacokinetic analysis revealed no significant difference in the area under the curve (AUC0-t), AUC0-∞, distribution half-life, elimination half-life, clearance, apparent volume of distribution, mean residence time or peak drug concentrations between the 2 groups (p > 0.05).

CONCLUSIONS

The ECMO circuit had an adsorption effect on dexmedetomidine hydrochloride, but this effect was not sufficient to impact the in vivo pharmacokinetics of dexmedetomidine significantly. The effect of ECMO on the pharmacokinetics of dexmedetomidine hydrochloride was not significant.

Application of a novel extracorporeal membrane oxygenation system in awake Hu sheep under various durations

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) provides effective support for respiratory and circulatory functions and stands as an essential means in the management of life-threatening conditions. This study aimed to evaluate the safety and efficacy of a novel ECMO system in awake sheep models across various support durations.

METHODS

Ten healthy Hu sheep were divided into venovenous (VV) and venoarterial (VA) groups, further categorized into short, medium, and long-term observation subgroups. Vital signs and blood indices were meticulously monitored. The integrity of heparin coatings and thrombosis in the ECMO system were assessed at indicated time points, followed by histopathological analysis.

RESULTS

All ten sheep survived to their planned endpoints under awake ECMO, exhibiting stable vital signs without notable reductions in blood cells. With the support of ECMO, all sheep demonstrated a significant increase in partial pressure of oxygen (PO2) and maintained oxygen saturation (SO2) between 99.8 and 100%. The heparin coating remained relatively intact even after prolonged ECMO operation. Anatomical observations and pathological histology analyses of major organs revealed no apparent abnormalities.

CONCLUSIONS

In healthy Hu sheep models with different maintenance periods, the novel ECMO support in awake state demonstrated high safety and feasibility.

Acute respiratory distress syndrome (ARDS): from mechanistic insights to therapeutic strategies

Acute respiratory distress syndrome (ARDS) is a clinical syndrome of acute hypoxic respiratory failure caused by diffuse lung inflammation and edema. ARDS can be precipitated by intrapulmonary factors or extrapulmonary factors, which can lead to severe hypoxemia. Patients suffering from ARDS have high mortality rates, including a 28-day mortality rate of 34.8% and an overall in-hospital mortality rate of 40.0%. The pathophysiology of ARDS is complex and involves the activation and dysregulation of multiple overlapping and interacting pathways of systemic inflammation and coagulation, including the respiratory system, circulatory system, and immune system. In general, the treatment of inflammatory injuries is a coordinated process that involves the downregulation of proinflammatory pathways and the upregulation of anti-inflammatory pathways. Given the complexity of the underlying disease, treatment needs to be tailored to the problem. Hence, we discuss the pathogenesis and treatment methods of affected organs, including 2019 coronavirus disease (COVID-19)-related pneumonia, drowning, trauma, blood transfusion, severe acute pancreatitis, and sepsis. This review is intended to provide a new perspective concerning ARDS and offer novel insight into future therapeutic interventions.

VENO-VENOUS EXTRACORPOREAL MEMBRANE OXYGENATION IMPROVES OUTCOMES IN TRAUMA PATIENTS SUFFERING RESPIRATORY FAILURE

ABSTRACT

Introduction: Veno-venous extracorporeal membrane oxygenation (VV ECMO) improves hypoxemia and carbon dioxide clearance in patients with severe respiratory derangements. A greater understanding of the potential benefits of VV ECMO in trauma patients could lead to broader adoption. We hypothesize that trauma patients who receive VV ECMO have improved mortality outcomes when compared to those receiving conventional ventilator management given the rapid stabilization VV ECMO promotes. Methods: We performed a single-center, propensity score-matched cohort study. All trauma patients from January 1, 2014, to October 30, 2023, who were placed on VV ECMO or who would have met institutional guidelines for VV ECMO but were managed with conventional ventilator strategies were matched 1:1. The primary outcome analysis was survival at hospital discharge. Significance was defined as P < 0.05. Results: Eighty-one trauma VV ECMO patients and 128 patients who received conventional management met criteria for inclusion. After matching, VV ECMO and conventional treatment cohort characteristics were similar in age and mechanism of injury. Matched ISS, SI, lactate levels, and frequency of traumatically brain injured were also similar. Finally, respiratory parameters including preintervention, pH, partial pressure of carbon dioxide, lactate levels, and oxygen saturation were similar between matched groups. VV ECMO patients had higher survival rates at discharge when compared to the matched conventional treatment group (70% vs. 41%, P < 0.001). Corresponding hazard ratio for VV ECMO use was 0.31 (95% CI 0.18-0.52; P < 0.001). The odds ratio of mortality in matched trauma patients who receive VV ECMO versus conventional treatment was 0.29 (95% CI 0.14-0.58; P < 0.001). Conclusion: VV ECMO may represent a safe, alternative treatment approach for appropriately screened trauma patients with acute respiratory failure; however, further studies are warranted.

Microbiological findings in a cohort of patients with coronavirus disease 2019 and venovenous extracorporeal membrane oxygenation

BACKGROUND

Venovenous extracorporeal membrane oxygenation (VV ECMO) is an established support option for patients with very severe respiratory failure and played an important role during the coronavirus disease 2019 (COVID-19) pandemic. Bacteria and fungi can lead to severe infectious complications in critically ill patients. The aim of this study was to describe the microbiological spectrum of bacteria and fungi detected in patients with COVID-19-associated respiratory failure supported with VV ECMO in our center.

METHODS

This retrospective single-center analysis included all patients with COVID-19-associated respiratory failure supported with VV ECMO in our center between March 2020 and May 2022. All findings from microbiological samples, taken as part of clinical routine assessment from initiation of VV ECMO until day 30 were included. Samples were described by site and time of detection and microbiological characteristics.

RESULTS

From March 2020 through May 2022, 88 patients with COVID-19-associated respiratory failure received VV ECMO support at our center. In 83/88 patients (94.3%), one or more pathogens were found in microbiological samples. Most pathogens were isolated from samples from the respiratory tract (88.6%). Earliest detection occurred in samples from the respiratory tract with a median time of 5 days to first detection. The most frequently detected pathogens were Staphylococcus spp., Candida spp., Klebsiella spp., Escherichia coli and Enterococcus spp.

CONCLUSION

In this cohort of severely ill COVID-19 patients receiving VV ECMO support, pathogens were frequently detected.

Improved Results Over Time With Bridge-to-Lung Transplantation: A 10-Year Experience of a Single High-Volume Center

When donor scarcity limits timely lung transplantation (LTx), extracorporeal membrane oxygenation (ECMO) as a bridge to transplantation (BTT) can prolong survival and delay deconditioning until the donor lungs become available. We reviewed 10-year BTT experiences of a single high-volume center, where 99 (59%) were on ECMO BTT among 169 eligible adult LTx cases. Both 28-day and 2-year survivals did not differ between BTT and non-BTT. The BTT data was then divided into two periods, delineated by the most recent 3 years. The clinical outcomes of the earlier period ("Period 1") and the later period ("Period 2") were compared, and mortality within 28 days of LTx was significantly lower in Period 2 (n = 1, 1.7%) than in Period 1 (n = 6, 14.6%, p < 0.01). Improved survival was observed in the subgroup with BTT duration of 14 days or more. Taken together, more experiences in BTT and improved competence may contribute to better survival after LTx, especially in patients receiving ECMO for 14 days or more.

Anticoagulation Can Be Held in Traumatically Injured Patients on Veno-Venous Extracorporeal Membrane Oxygenation Support

Traumatic injury is associated with several pulmonary complications, including pulmonary contusion, transfusion-related acute lung injury (TRALI), and the development of acute respiratory distress syndrome (ARDS). There is a lack of literature on these patients supported with veno-venous extracorporeal oxygenation (VV ECMO). Understanding the safety of using VV ECMO to support trauma patients and the ability to hold anticoagulation is important to broaden utilization. This is a single-center retrospective cohort study of adult trauma patients cannulated for VV ECMO during their initial admission over an 8 year period (2014-2021). We hypothesize that anticoagulation can be held in trauma patients on VV ECMO without increasing mortality or prothrombotic complications. We also describe the coagulopathy of traumatically injured patients on VV ECMO. Withholding anticoagulation was not associated with mortality in our study population, and there were no significant differences in bleeding or clotting complications between patients who did and did not receive systemic anticoagulation. Patients in the nonsurvivor group had increased coagulopathy both pre- and post-cannulation. Our study suggests anticoagulation can be safely withheld in traumatically injured VV ECMO patients without increasing mortality, complication rates, or transfusion requirements. Future, multicenter prospective studies with larger sample sizes are required to confirm our results.

Echocardiographic Findings in Critically Ill COVID-19 Patients Treated With and Without Extracorporeal Membrane Oxygenation

OBJECTIVES

To describe echocardiographic findings among mechanically ventilated patients with COVID-19 acute respiratory distress syndrome, comparing those with and without venovenous extracorporeal membrane oxygenation (VV ECMO) support.

DESIGN

Single-center, retrospective cohort study.

SETTING

Intensive care unit (ICU) of a quaternary academic center.

PARTICIPANTS

Patients with COVID-19 admitted between March 2020 and June 2021 receiving mechanical ventilation, with an echocardiogram within 72 hours of admission.

INTERVENTIONS

Admission and follow-up echocardiograms during ICU stay.

MEASUREMENTS

Patient characteristics and echocardiographic findings were analyzed. Mortality odds ratio (OR) for right ventricular (RV) systolic dysfunction and acute cor pulmonale (ACP) was calculated.

MAIN RESULTS

Among 242 patients, 145 (60%) received VV ECMO. Median (IQR) PaO2/FiO2 was 76 (65-95) and 98 (85-140) in ECMO and non-ECMO patients, respectively (p ≤ 0.001). Initial echocardiograms showed no significant differences in left ventricular systolic dysfunction (10% v 15 %, p = 0.31) and RV systolic dysfunction (38% v. 27%, p = 0.27) between ECMO and non-ECMO patients. ACP was more frequent in the ECMO group at baseline (41% v. 26 %, p = 0.02). During the ICU stay, patients on ECMO exhibited a higher prevalence of RV systolic dysfunction (55% v 34%, p = 0.001) and ACP (51% v 26%, p = 0.002). RV systolic dysfunction (OR 1.99; 95% CI 1.09-3.63) and ACP (OR 2.95; 95% CI 1.55-5.62) on the follow-up echocardiograms were associated with higher odds of ICU mortality.

CONCLUSIONS

The prevalence of echocardiographic abnormalities, in particular RV dysfunction, was frequent among patients with COVID-19 receiving VV ECMO support and was associated with worse clinical outcomes.

Increased national critical care demands were associated with a higher mortality of intubated COVID-19 patients in Japan: a retrospective observational study

BACKGROUND

There was no study to investigate the association between the national surge of Coronavirus disease 2019 (COVID-19) patients and the mortality of mechanically ventilated COVID-19 patients. The aim of this study was to assess the association between mortality in mechanically ventilated COVID-19 patients and two distinct national COVID-19 surge indices: (1) the daily number of newly confirmed COVID-19 cases, representing overall medical demands and (2) the total number of critically ill COVID-19 patients, reflecting critical care demands.

METHODS

We analyzed the patient data registered in a national database of mechanically ventilated COVID-19 patients between February 6, 2020, and May 16, 2023, combined with the data officially published by the Japanese government. Multivariable logistic regression analysis was performed to evaluate the association of these two indices with COVID-19 mortality. A generalized linear mixed effect model was used to examine the relationships between the variation in the impact of critical care demands across hospitals and the variation in baseline risk across hospitals.

RESULTS

The data of 8327 patients from 264 centers in Japan were analyzed. The overall mortality rate was 24% (1990/8327). The critical care demands, but not overall medical demands, were independently associated with the mortality (OR, 1.11; 95% CI 1.07-1.16; p < 0.001). This effect of critical care demands on the mortality was more pronounced in hospitals with higher baseline risk (r = 0.67).

CONCLUSIONS

The national critical care demands were independently associated with the mortality of COVID-19 patients requiring mechanical ventilation. This effect was more pronounced in hospitals with higher baseline risk.

Prediction of Thrombus Formation within an Oxygenator via Bioimpedance Analysis

Blood clot formation inside the membrane oxygenator (MO) remains a risk in extracorporeal membrane oxygenation (ECMO). It is associated with thromboembolic complications and normally detectable only at an advanced stage. Established clinical monitoring techniques lack predictive capabilities, emphasizing the need for refinement in MO monitoring towards an early warning system. In this study, an MO was modified by integrating four sensor fibers in the middle of the hollow fiber mat bundle, allowing for bioimpedance measurement within the MO. The modified MO was perfused with human blood in an in vitro test circuit until fulminant clot formation. The optical analysis of clot residues on the extracted hollow fibers showed a clot deposition area of 51.88% ± 14.25%. This was detectable via an increased bioimpedance signal with a significant increase 5 min in advance to fulminant clot formation inside the MO, which was monitored by the clinical gold standard (pressure difference across the MO (dp-MO)). This study demonstrates the feasibility of detecting clot growth early and effectively by measuring bioimpedance within an MO using integrated sensor fibers. Thus, bioimpedance may even outperform the clinical gold standard of dp-MO as a monitoring method by providing earlier clot detection.

Use of Extracorporeal Membrane Oxygenation for Patients with Coronavirus Disease 2019 Infection

The coronavirus disease 2019 (COVID-19) pandemic was a cataclysmic event that infected over 772 million and killed over 6.9 million people worldwide. The pandemic pushed hospitals and society to their limits and resulted in incredibly severe respiratory disease in millions of people. This severe respiratory disease often necessitated maximum medical therapy, including the use of extracorporeal membrane oxygenation. While our understanding of COVID-19 and its treatment continue to evolve, we review the current evidence to guide the care of patients with severe COVID-19 infection.

Ethics Consultation in Anesthesia Practice

Because modern surgical and medical care have advanced, patients increasingly present for procedural and surgical intervention with life-limiting diagnoses and/or advanced care goals such as "do not resuscitate." Anesthesiologists now care for these patients across the complete perioperative setting and frequently find themselves at the crossroads of these mounting pressures. As the boundaries and capabilities of anesthetic care and critical care anesthesiology expand so too do the specialty's needs for support in ethical decision-making. Herein, we review the role of the ethics consultation in anesthesia practice and special ethic issues encountered by the anesthesiologist.

Ketamine Use in Adult and Pediatric Patients Receiving Extracorporeal Membrane Oxygenation (ECMO): A Systematic Review

Background: Analgesia and sedation are often critical elements of therapy for patients undergoing extracorporeal membrane oxygenation (ECMO). Aside from potential drug-drug interactions, the PK changes associated with ECMO make appropriate analgosedative selection challenging. Ketamine is less lipophilic and has lower protein binding than alternative agents, and may be less impacted by the PK changes during ECMO. Objective: To systematically identify all instances of ketamine use during ECMO support in the literature to elucidate associated efficacy and safety outcomes and prevalence of use, as well as commonly used dosing strategies and pharmacokinetic data. Methods: Web of Science, Cochrane Library, Scopus, Ovid MEDLINE, PubMed, and OVID Embase were searched through 02/2023 using keywords ketamine and ECMO or extracorporal life support (ECLS). Case reports, case series, and studies were included that had (1) original data, (2) included patients that were on ECMO and continuous infusion ketamine, and (3) reported pertinent ketamine related clinical endpoints or prevalence of use. Results: Of the 307 articles screened, 25 were identified as relevant and 11 met our inclusion criteria. Heterogeneity of patient population, ketamine indication, reported outcomes, and reported safety endpoints were identified in the included articles. Commonly reported information includes indications, pharmacokinetics, dosing, adverse effects and use in pediatrics for ketamine, and suspected opioid sparing effect. Conclusion: Our review has found a lack of consistency in reporting and results in adult and pediatric patients. Increased consistency in reporting and larger studies are required to increase our knowledge of ketamine use in both the adult and pediatric patient population.

Using the sympathetic system, beta blockers and alpha-2 agonists, to address acute respiratory distress syndrome

Acute Respiratory Distress Syndrome (ARDS) manifests as an acute inflammatory lung injury characterized by persistent hypoxemia, featuring a swift onset, high mortality, and predominantly supportive care as the current therapeutic approach, while effective treatments remain an area of active investigation. Adrenergic receptors (AR) play a pivotal role as stress hormone receptors, extensively participating in various inflammatory processes by initiating downstream signaling pathways. Advancements in molecular biology and pharmacology continually unveil the physiological significance of distinct AR subtypes. Interventions targeting these subtypes have the potential to induce specific alterations in cellular and organismal functions, presenting a promising avenue as a therapeutic target for managing ARDS. This article elucidates the pathogenesis of ARDS and the basic structure and function of AR. It also explores the relationship between AR and ARDS from the perspective of different AR subtypes, aiming to provide new insights for the improvement of ARDS.

Nonlinear relationship between platelet count and 30-day in-hospital mortality in ICU acute respiratory failure patients: a multicenter retrospective cohort study

BACKGROUND

Limited evidence exists regarding the link between platelet count and 30-day in-hospital mortality in acute respiratory failure (ARF) patients. Thus, this study aims to investigate this association among ICU patients experiencing acute respiratory failure.

METHODS

We conducted a retrospective cohort study across multiple centers, utilizing data from the US eICU-CRD v2.0 database covering 22,262 patients with ARF in the ICU from 2014 to 2015. Our aim was to investigate the correlation between platelet count and 30-day in-hospital mortality using binary logistic regression, subgroup analyses, and smooth curve fitting.

RESULTS

The 30-day in-hospital mortality rate was 19.73% (4393 out of 22,262), with a median platelet count of 213 × 109/L. After adjusting for covariates, our analysis revealed an inverse association between platelet count and 30-day in-hospital mortality (OR = 0.99, 95% CI 0.99, 0.99). Subgroup analyses supported the robustness of these findings. Furthermore, a nonlinear relationship was identified between platelet count and 30-day in-hospital mortality, with the inflection point at 120 × 109/L. Below the inflection point, the effect size (OR) was 0.89 (0.87, 0.91), indicating a significant association. However, beyond this point, the relationship was not statistically significant.

CONCLUSION

This study establishes a clear negative association between platelet count and 30-day in-hospital mortality among ICU patients with ARF. Furthermore, we have identified a nonlinear relationship with saturation effects, indicating that among ICU patients with acute respiratory failure, the lowest 30-day in-hospital mortality rate occurs when the baseline platelet count is approximately 120 × 109/L.

Long term outcome in patients treated with veno-venous extracorporeal membrane oxygenation: A prospective observational study

INTRODUCTION

Over the last few decades, the use of veno-venous extracorporeal membrane oxygenation (VV-ECMO) support for severe respiratory failure has increased.

AIM

This study aimed to assess the long-term outcomes of patients treated with VV-ECMO for respiratory failure.

METHODS

We performed a single-centre prospective evaluation of patients on VV-ECMO who were successfully discharged from the intensive care unit of an Italian University Hospital between January 2018 and May 2021. The enrolled patients underwent follow-up evaluations at 6 and 12 months after ICU discharge. The follow-up team performed psychological and functional assessments using the following instruments: Hospital Anxiety and Depression Scale (HADS), Post-traumatic Stress Disorder Symptom Severity Scale (PTSS-10), Euro Quality Five Domains Five Levels (EQ-5L-5D), and 6-minute walk test.

RESULTS

We enrolled 33 patients who were evaluated at a follow-up clinic. The median patient age was 51 years (range: 45-58 years). The median duration of VV-ECMO support was 12 (9-19) days and the length of ICU stay was 23 (18-42) days. A HADS score higher than 14 was reported in 8 (24 %) and 7 (21 %) patients at the six- and twelve-month visit, respectively. PTSS-10 total score ≥ 35 points was present in three (9 %) and two (6 %) patients at the six- and twelve-month examination. The median EQ-5L-5D-VAS was respectively 80 (80-90) and 87.5 (70-95). The PTSS-10 score significantly decreased from six to 12 months in COVID-19 survivors (p = 0.024).

CONCLUSIONS

In this cohort of patients treated with VV-ECMO, cognitive and psychological outcomes were good and comparable to those of patients with Adult Respiratory Distress Syndrome (ARDS) managed without ECMO.

IMPLICATIONS FOR CLINICAL PRACTICE

The findings of this study confirm the need for long-term follow-up and rehabilitation programs for every ICU survivor after discharge. COVID-19 survivors treated with VV-ECMO had outcomes comparable to those reported in non-COVID patients.

"Decompression illness" on extracorporeal membrane oxygenation

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is increasingly being used for critically ill patients with cardiopulmonary failure. Air in the ECMO circuit is an emergency, a rare but fatal complication.

CASE PRESENTATION

We introduce a case of a 76-year-old female who suffered from cardiac arrest complicated with severe trauma and was administered veno-arterial extracorporeal membrane oxygenation. In managing the patient with ECMO, air entered the ECMO circuit, which had not come out nor was folded or broken. Although the ECMO flow was quickly re-established, the patient died 6 h after initiating ECMO therapy.

CONCLUSIONS

In this case report, the reason for the complication is drainage insufficiency. This phenomenon is similar to decompression sickness. Understanding this complication is very helpful for educating the ECMO team for preventing this rare but devastating complication of fatal decompression sickness in patients on ECMO.

Prevalence and Survival of Prolonged Venovenous Extracorporeal Membrane Oxygenation for Acute Respiratory Distress Syndrome: An Analysis of the Extracorporeal Life Support Organization Registry

OBJECTIVES

To examine trends in utilization and outcomes among patients with the acute respiratory distress syndrome (ARDS) requiring prolonged venovenous extracorporeal membrane oxygenation (VV ECMO) support.

DESIGN

Retrospective observational cohort study.

SETTING

Adult patients in the Extracorporeal Life Support Organization registry.

PATIENTS

Thirteen thousand six hundred eighty-one patients that required ECMO for the support of ARDS between January 2012 and December 2022.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Mortality while supported with VV ECMO and survival to hospital discharge based on ECMO duration were examined utilizing multivariable logistic regression. Among the 13,681 patients supported with VV ECMO, 4,040 (29.5%) were supported for greater than or equal to 21 days and 975 (7.1%) for greater than or equal to 50 days. Patients supported with prolonged VV ECMO were less likely to be discharged alive from the hospital compared with those with short duration of support (46.5% vs. 59.7%; p < 0.001). However, among patients supported with VV ECMO greater than or equal to 21 days, duration of extracorporeal life support was not significantly associated with mortality (odds ratio [OR], 0.99; 95% CI, 0.98-1.01; p = 0.87 and adjusted OR, 0.99; 95% CI, 0.97-1.02; p = 0.48). Even in those supported with VV ECMO for at least 120 days (n = 113), 52 (46.0%) of these patients were ultimately discharged alive from the hospital.

CONCLUSIONS

Prolonged VV ECMO support of ARDS has increased and accounts for a substantial portion of cases. Among patients that survive for greater than or equal to 21 days while receiving VV ECMO support, duration is not predictive of survival to hospital discharge and clinical recovery may occur even after very prolonged VV ECMO support.

ICU Nurses' Perception of Sensitive Indicators of Quality of Care for ECMO Patients in Guizhou Province, China: A Cross-Sectional Study

Purpose

This study aimed to investigate the cognitive evaluation level of ICU nurses in Guizhou Province, China, on the sensitivity indicators of nursing quality for ECMO patients.

Patients and Methods

This was a cross-sectional observational study conducted in Guizhou Province, China, from May to July 2023, 259 ICU nurses were surveyed. Objective sampling method was used to select the participants from 10 hospitals in Guizhou Province that carried out ECMO. Data were collected through questionnaire survey. Two researchers checked and recorded Epidata 3.1. SPSS 25.0 was used for statistical analysis of the data, and frequency, mean and component ratio were used for descriptive statistical analysis. The importance rating was used to reflect the degree of nurses' agreement with the indicators.

Results

The results of this study showed that 79.1% of the 253 ICU nurses in Guizhou Province, China, had not participated in training and courses related to indicators of quality of care evaluation for ECMO patients. The main way for ICU nurses to acquire knowledge related to indicators of quality of care sensitivity for ECMO patients was departmental training, which accounted for 87.4%. And the other ways, in descending order, were public, the matic lectures or academic conferences, journals and magazines; their evaluation scores of the importance of most of the quality of care sensitivity indicators for ECMO patients was moderate, with the scores ranging from 73 to 150. Among them, the range of importance evaluation scores for each indicator was 4.01 ~ 4.48.

Conclusion

The overall cognitive evaluation of ICU nurses in Guizhou Province, China, on most sensitivity indicators of quality of care for ECMO patients was moderate, and there is a general lack of systematic courses and training on the knowledge related to ECMO care quality sensitive indicators.

Pulmonary redox imbalance drives early fibroproliferative response in moderate/severe coronavirus disease-19 acute respiratory distress syndrome and impacts long-term lung abnormalities

BACKGROUND

COVID-19-associated pulmonary fibrosis remains frequent. This study aimed to investigate pulmonary redox balance in COVID-19 ARDS patients and possible relationship with pulmonary fibrosis and long-term lung abnormalities.

METHODS

Baseline data, chest CT fibrosis scores, N-terminal peptide of alveolar collagen III (NT-PCP-III), transforming growth factor (TGF)-β1, superoxide dismutase (SOD), reduced glutathione (GSH), oxidized glutathione (GSSG) and malondialdehyde (MDA) in bronchoalveolar lavage fluid (BALF) were first collected and compared between SARS-CoV-2 RNA positive patients with moderate to severe ARDS (n = 65, COVID-19 ARDS) and SARS-CoV-2 RNA negative non-ARDS patients requiring mechanical ventilation (n = 63, non-ARDS). Then, correlations between fibroproliferative (NT-PCP-III and TGF-β1) and redox markers were analyzed within COVID-19 ARDS group, and comparisons between survivor and non-survivor subgroups were performed. Finally, follow-up of COVID-19 ARDS survivors was performed to analyze the relationship between pulmonary abnormalities, fibroproliferative and redox markers 3 months after discharge.

RESULTS

Compared with non-ARDS group, COVID-19 ARDS group had significantly elevated chest CT fibrosis scores (p < 0.001) and NT-PCP-III (p < 0.001), TGF-β1 (p < 0.001), GSSG (p < 0.001), and MDA (p < 0.001) concentrations on admission, while decreased SOD (p < 0.001) and GSH (p < 0.001) levels were observed in BALF. Both NT-PCP-III and TGF-β1 in BALF from COVID-19 ARDS group were directly correlated with GSSG (p < 0.001) and MDA (p < 0.001) and were inversely correlated with SOD (p < 0.001) and GSH (p < 0.001). Within COVID-19 ARDS group, non-survivors (n = 28) showed significant pulmonary fibroproliferation (p < 0.001) with more severe redox imbalance (p < 0.001) than survivors (n = 37). Furthermore, according to data from COVID-19 ARDS survivor follow-up (n = 37), radiographic residual pulmonary fibrosis and lung function impairment improved 3 months after discharge compared with discharge (p < 0.001) and were associated with early pulmonary fibroproliferation and redox imbalance (p < 0.01).

CONCLUSIONS

Pulmonary redox imbalance occurring early in COVID-19 ARDS patients drives fibroproliferative response and increases the risk of death. Long-term lung abnormalities post-COVID-19 are associated with early pulmonary fibroproliferation and redox imbalance.

Web-based Dashboard on ECMO Utilization in Germany: An Interactive Visualization, Analyses, and Prediction Based on Real-life Data

In Germany, a comprehensive reimbursement policy for extracorporeal membrane oxygenation (ECMO) results in the highest per capita use worldwide, although benefits remain controversial. Public ECMO data is unstructured and poorly accessible to healthcare professionals, researchers, and policymakers. In addition, there are no uniform policies for ECMO allocation which confronts medical personnel with ethical considerations during health crises such as respiratory virus outbreaks.Retrospective information on adult and pediatric ECMO support performed in German hospitals was extracted from publicly available reimbursement data and hospital quality reports and processed to create the web-based ECMO Dashboard built on Open-Source software. Patient-level and hospital-level data were merged resulting in a solid base for ECMO use analysis and ECMO demand forecasting with high spatial granularity at the level of 413 county and city districts in Germany.The ECMO Dashboard ( https://www.ecmo-dash.de/ ), an innovative visual platform, presents the retrospective utilization patterns of ECMO support in Germany. It features interactive maps, comprehensive charts, and tables, providing insights at the hospital, district, and national levels. This tool also highlights the high prevalence of ECMO support in Germany and emphasizes districts with ECMO surplus - where patients from other regions are treated, or deficit - origins from which ECMO patients are transferred to other regions. The dashboard will evolve iteratively to provide stakeholders with vital information for informed and transparent resource allocation and decision-making.Accessible public routine data could support evidence-informed, forward-looking resource management policies, which are urgently needed to increase the quality and prepare the critical care infrastructure for future pandemics.

Hemorrhage and thrombosis in COVID-19-patients supported with extracorporeal membrane oxygenation: an international study based on the COVID-19 critical care consortium

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is a rescue therapy in patients with severe acute respiratory distress syndrome (ARDS) secondary to COVID-19. While bleeding and thrombosis complicate ECMO, these events may also occur secondary to COVID-19. Data regarding bleeding and thrombotic events in COVID-19 patients on ECMO are sparse.

METHODS

Using the COVID-19 Critical Care Consortium database, we conducted a retrospective analysis on adult patients with severe COVID-19 requiring ECMO, including centers globally from 01/2020 to 06/2022, to determine the risk of ICU mortality associated with the occurrence of bleeding and clotting disorders.

RESULTS

Among 1,248 COVID-19 patients receiving ECMO support in the registry, coagulation complications were reported in 469 cases (38%), among whom 252 (54%) experienced hemorrhagic complications, 165 (35%) thrombotic complications, and 52 (11%) both. The hazard ratio (HR) for Intensive Care Unit mortality was higher in those with hemorrhagic-only complications than those with neither complication (adjusted HR = 1.60, 95% CI 1.28-1.99, p < 0.001). Death was reported in 617 of the 1248 (49.4%) with multiorgan failure (n = 257 of 617 [42%]), followed by respiratory failure (n = 130 of 617 [21%]) and septic shock [n = 55 of 617 (8.9%)] the leading causes.

CONCLUSIONS

Coagulation disorders are frequent in COVID-19 ARDS patients receiving ECMO. Bleeding events contribute substantially to mortality in this cohort. However, this risk may be lower than previously reported in single-nation studies or early case reports. Trial registration ACTRN12620000421932 ( https://covid19.cochrane.org/studies/crs-13513201 ).

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.

[The center for intensive care medicine: a model for interdisciplinary and interprofessional collaboration]

BACKGROUND

The Federal Joint Committee has established requirements for centers for intensive care medicine which, in cooperation with other clinics, are to take on special tasks for intensive care medicine in a region. High demands are placed on these centers, which it may not be possible to meet without restructuring the existing intensive care structures.

OBJECTIVE

In this study, an organizational model for a center for intensive care medicine based on broad interdisciplinary and interprofessional cooperation is presented for discussion.

METHODS AND RESULTS

The organizational model contains proposals for integration of the centers for intensive care medicine into the clinic structure, the management team, the staff composition, the areas of clinical activity, and the further tasks of research, teaching, and education and training.

CONCLUSION

Establishment of the centers for intensive care medicine provides new and forward-looking impetus for the further development of intensive care medicine in Germany. However, for the new organizational model to be implemented effectively, the necessary restructuring measures must be adequately refinanced and supported by hospital management and medical faculties. In addition, a sustained willingness for interdisciplinary and interprofessional cooperation is required on the part of all those involved, and employees in this model must be offered attractive long-term positions in intensive care medicine.

Novel tubing connectors reduce ECMO circuit thrombosis

BACKGROUND

Thrombosis within extracorporeal membrane oxygenation (ECMO) circuits is a common complication that dominates clinical management of patients receiving mechanical circulatory support. Prior studies have identified that over 80% of circuit thrombosis can be attributed to tubing-connector junctions.

METHODS

A novel connector was designed that reduces local regions of flow stagnation at the tubing-connector junction to eliminate a primary source of ECMO circuit thrombi. To compare clotting between the novel connectors and the traditional connectors, both in vitro loops and an in vivo caprine model of long-term (48 h) ECMO were used to generate tubing-connector junction clots.

RESULTS

In vitro, the traditional connectors uniformly (9/9) formed large thrombi, while novel connectors formed a small thrombus in only one of nine (p < 0.0001). In the long-term goat ECMO circuits, the traditional connectors exhibited more thrombi (p < 0.04), and these thrombi were more likely to protrude into the lumen of the tubing (p < 0.001).

CONCLUSION

Both in vitro and in vivo validation experiments successfully recreated circuit thrombosis and demonstrate that the adoption of novel connectors can reduce the burden of circuit thrombosis.

Risk Factors for the Mortality of Patients With Coronavirus Disease 2019 Requiring Extracorporeal Membrane Oxygenation in a Non-Centralized Setting: A Nationwide Study

BACKGROUND

Limited data are available on the mortality rates of patients receiving extracorporeal membrane oxygenation (ECMO) support for coronavirus disease 2019 (COVID-19). We aimed to analyze the relationship between COVID-19 and clinical outcomes for patients receiving ECMO.

METHODS

We retrospectively investigated patients with COVID-19 pneumonia requiring ECMO in 19 hospitals across Korea from January 1, 2020 to August 31, 2021. The primary outcome was the 90-day mortality after ECMO initiation. We performed multivariate analysis using a logistic regression model to estimate the odds ratio (OR) of 90-day mortality. Survival differences were analyzed using the Kaplan-Meier (KM) method.

RESULTS

Of 127 patients with COVID-19 pneumonia who received ECMO, 70 patients (55.1%) died within 90 days of ECMO initiation. The median age was 64 years, and 63% of patients were male. The incidence of ECMO was increased with age but was decreased after 70 years of age. However, the survival rate was decreased linearly with age. In multivariate analysis, age (OR, 1.048; 95% confidence interval [CI], 1.010-1.089; P = 0.014) and receipt of continuous renal replacement therapy (CRRT) (OR, 3.069; 95% CI, 1.312-7.180; P = 0.010) were significantly associated with an increased risk of 90-day mortality. KM curves showed significant differences in survival between groups according to age (65 years) (log-rank P = 0.021) and receipt of CRRT (log-rank P = 0.004).

CONCLUSION

Older age and receipt of CRRT were associated with higher mortality rates among patients with COVID-19 who received ECMO.

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.

Anticoagulation and Bleeding during Veno-Venous Extracorporeal Membrane Oxygenation: Insights from the PROTECMO Study

Rationale: Definitive guidelines for anticoagulation management during veno-venous extracorporeal membrane oxygenation (VV ECMO) are lacking, whereas bleeding complications continue to pose major challenges. Objectives: To describe anticoagulation modalities and bleeding events in adults receiving VV ECMO. Methods: This was an international prospective observational study in 41 centers, from December 2018 to February 2021. Anticoagulation was recorded daily in terms of type, dosage, and monitoring strategy. Bleeding events were reported according to site, severity, and impact on mortality. Measurements and Main Results: The study cohort included 652 patients, and 8,471 days on ECMO were analyzed. Unfractionated heparin was the initial anticoagulant in 77% of patients, and the most frequently used anticoagulant during the ECMO course (6,221 d; 73%). Activated partial thromboplastin time (aPTT) was the most common test for monitoring coagulation (86% of days): the median value was 52 seconds (interquartile range, 39 to 61 s) but dropped by 5.3 seconds after the first bleeding event (95% confidence interval, -7.4 to -3.2; P < 0.01). Bleeding occurred on 1,202 days (16.5%). Overall, 342 patients (52.5%) experienced at least one bleeding event (one episode every 215 h on ECMO), of which 10 (1.6%) were fatal. In a multiple penalized Cox proportional hazard model, higher aPTT was a potentially modifiable risk factor for the first episode of bleeding (for 20-s increase; hazard ratio, 1.07). Conclusions: Anticoagulation during VV ECMO was a dynamic process, with frequent stopping in cases of bleeding and restart according to the clinical picture. Future studies might explore lower aPTT targets to reduce the risk of bleeding.

A risk score for predicting extracorporeal membrane oxygenation support before lung transplantation

Background

Extracorporeal membrane oxygenation (ECMO) has been increasingly used as life support for lung transplantation. However, there are no clinical risk models to predict whether ECMO support is required for lung transplantation. This study developed a simple risk score to predict the need for intraoperative ECMO in patients undergoing lung transplantation, identify high-risk patients who need ECMO support, and guide clinical interventions.

Methods

Patients, who underwent lung transplantation between January 1, 2016 and July 31, 2021, were systematically reviewed. All enrolled patients were divided in a ratio of 7:3 to establish the development and validation datasets. A risk score model was established using stepwise logistic regression and verified using bootstrapping and the split-sample method.

Results

A total of 248 patients who underwent lung transplants were enrolled. Multivariate analysis showed that the primary disease diagnosis, pulmonary artery systolic pressure, sex, surgical type, creatine kinase isoenzyme-MB, and pro-B-type natriuretic peptide were risk factors for intraoperative ECMO during lung transplantation. The risk score was established and calibrated according to these six factors, ranging from 0 to 41, with the associated prediction of intraoperative use of ECMO ranging from 1.5% to 99.7% (Hosmer-Lemeshow χ2=5.624; P=0.689). Good discrimination was verified by developing and validating the datasets (C-statistics =0.850 and 0.842, respectively). Based on the distribution of the scores, the three levels were classified as low-risk (0-10], moderate-risk (10-20], and high-risk (20-41].

Conclusions

This simple risk score model effectively predicts the need for intraoperative ECMO and stratifies high-risk patients who require ECMO support.

A time series driven model for early sepsis prediction based on transformer module

Sepsis remains a critical concern in intensive care units due to its high mortality rate. Early identification and intervention are paramount to improving patient outcomes. In this study, we have proposed predictive models for early sepsis prediction based on time-series data, utilizing both CNN-Transformer and LSTM-Transformer architectures. By collecting time-series data from patients at 4, 8, and 12 h prior to sepsis diagnosis and subjecting it to various network models for analysis and comparison. In contrast to traditional recurrent neural networks, our model exhibited a substantial improvement of approximately 20%. On average, our model demonstrated an accuracy of 0.964 (± 0.018), a precision of 0.956 (± 0.012), a recall of 0.967 (± 0.012), and an F1 score of 0.959 (± 0.014). Furthermore, by adjusting the time window, it was observed that the Transformer-based model demonstrated exceptional predictive capabilities, particularly within the earlier time window (i.e., 12 h before onset), thus holding significant promise for early clinical diagnosis and intervention. Besides, we employed the SHAP algorithm to visualize the weight distribution of different features, enhancing the interpretability of our model and facilitating early clinical diagnosis and intervention.

An Integrative Review: Evaluating the Risks, Benefits, and Efficacy of Extracorporeal Membrane Oxygenation (ECMO) in Treating ARDS Secondary to COVID-19

The onset of the COVID-19 pandemic has led to an increased use of extracorporeal membrane oxygenation (ECMO) for severe acute respiratory distress syndrome (ARDS); however, there are ongoing concerns about its associated risks and benefits, making a comprehensive understanding vital for clinical decision-making. This review aims to evaluate the efficacy, risks, and practical implications of ECMO as a therapeutic intervention in severe ARDS secondary to COVID-19. The results indicate that ECMO is a key therapeutic intervention for managing severe COVID-19, but due to its associated risks and resource constraints, its application needs careful consideration. Nurse practitioners need to acquire specialized skills to manage ECMO and stay updated with ongoing research and revised protocols. Given the potential for future virus mutations or pandemics, and finite resources, a multidisciplinary approach to ECMO therapy is necessary. Careful patient selection, strategic resource allocation, and continuous education are pivotal elements for improved patient outcomes.

Catalase: A Potential Pharmacologic Target for Hydrogen Peroxide in the Treatment of COVID-19

BACKGROUND

Acute respiratory distress syndrome in the elderly with COVID-19 complicated by airway obstruction with sputum and mucus, and cases of asphyxia with blood, serous fluid, pus, or meconium in newborns and people of different ages can sometimes cause hypoxemia and death from hypoxic damage to brain cells, because the medical standard does not include intrapulmonary injections of oxygen-producing solutions. The physical-chemical repurposing of hydrogen peroxide from an antiseptic to an oxygen-producing antihypoxant offers hope for the development of new drugs.

METHODS

This manuscript is a meta-analysis performed according to PRISMA guidelines.

RESULTS

It is shown that replacement of the traditional acidic activity of hydrogen peroxide solutions by alkaline activity with pH 8.4 and heating the solutions to the temperature of +37 - +42 °C allows to repurpose hydrogen peroxide from antiseptics into inhalation and intrapulmonary mucolytics, pyolytics and antihypoxants releasing oxygen. The fact is that warm alkaline hydrogen peroxide solution (WAHPS) in local interaction with sputum, mucus, pus, blood and meconium provides optimal conditions for the metabolism of hydrogen peroxide to oxygen gas under the action of the enzyme catalase, always present in these tissues. It was established that WAHPS liquefies these biological masses due to alkaline saponification of lipid and protein-lipid complexes and simultaneously transforms dense masses into soft oxygen foam due to active enzymatic metabolism of hydrogen peroxide to oxygen gas, the rapidly appearing bubbles of which are formed by the type of "cold boiling" and literally explode these masses. The results of the first experiments showed that inhalation and intrapulmonary injections of WAHPS can significantly optimize the treatment of suffocation and hypoxemia.

DISCUSSION

The results showed that catalase, which is found in sputum, mucus, pus, and blood, may be a target for localized WAHPS because this enzyme provides an intensive metabolism of hydrogen peroxide to oxygen gas up to the formation of the cold boiling process.

CONCLUSION

These data provide a new perspective way for intrapulmonary drugs and new technologies for the emergency increase of blood oxygenation through the lungs in asphyxia with thick sputum, mucus, pus, meconium and blood.

Tracheostomy in Critically Ill COVID-19 Patients on Extracorporeal Membrane Oxygenation: A Single-Center Experience

OBJECTIVES

Novel coronavirus-19 (COVID-19) has led to over 6 million fatalities globally. An estimated 75% of COVID-19 patients who require critical care admission develop acute respiratory distress syndrome (ARDS) needing invasive mechanical ventilation (IMV) and/or extracorporeal membrane oxygenation (ECMO). Due to prolonged ventilation requirements, these patients often also require tracheostomy. We performed a review of clinical outcomes in COVID-19 patients on ECMO at a high-volume tertiary care center in Hamilton, Ontario, Canada.

METHODOLOGY

We performed a retrospective case series, including 24 adult patients diagnosed with COVID-19 who required IMV, veno-venous (ECMO), and tracheostomy. All patients were included from April to December 2021. We extracted demographic and clinical variables pertaining to the tracheostomy procedure and ECMO therapy. We performed descriptive statistical analyses. This study was approved by the Hamilton Integrated Research Ethics Board (14217-C).

RESULTS

We included 24 consecutive patients with COVID-19 who required tracheostomy while undergoing ECMO therapy. The mean age was 49.4 years [standard deviation (SD): 7.33], the majority of patients were male (75%), with mean body mass index of 32 (SD: 8.81). Overall mortality rate was 33.3%. Percutaneous tracheostomy was performed most frequently (83.3%) and, similar to open tracheostomy, was associated with a low rate of perioperative bleeding complications. Within surviving patients, the mean time to IMV weaning and decannulation was 60.2 (SD: 24.6) and 49.4 days (SD: 21.8), respectively.

CONCLUSION

Percutaneous tracheostomy appears to be safe in COVID-19 patients on ECMO and holding anticoagulation 24 hours prior to and after tracheostomy may limit bleeding events in these patients.

Anticoagulants in adult extracorporeal membrane oxygenation: alternatives to standardized anticoagulation with unfractionated heparin

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is a vital technique for severe respiratory or heart failure patients. Bleeding and thrombotic events are common during ECMO and negatively impact patient outcomes. Unfractionated heparin is the primary anticoagulant, but its adverse effects limit its use, necessitating alternative anticoagulants.

OBJECTIVE

Review available alternative anticoagulants for adult ECMO patients. Explore potential novel anticoagulants for future ECMO use. Aim to reduce complications (bleeding and thrombosis) and improve safety and efficacy for critically ill ECMO patients.

METHODS

Comprehensive literature review of existing and emerging anticoagulants for ECMO.

RESULTS

Identified a range of alternative anticoagulants beyond unfractionated heparin. Evaluated their potential utility in mitigating ECMO-related complications.

CONCLUSION

Diverse anticoagulant options are available and under investigation for ECMO. These alternatives may enhance patient safety and outcomes during ECMO support. Further research and clinical studies are warranted to determine their effectiveness and safety profiles.

Post-Mortem Extracorporeal Membrane Oxygenation Perfusion Rat Model: A Feasibility Study

The development of biomedical soft- or hardware frequently includes testing in animals. However, large efforts have been made to reduce the number of animal experiments, according to the 3Rs principle. Simultaneously, a significant number of surplus animals are euthanized without scientific necessity. The primary aim of this study was to establish a post-mortem rat perfusion model using extracorporeal membrane oxygenation (ECMO) in surplus rat cadavers and generate first post vivo results concerning the oxygenation performance of a recently developed ECMO membrane oxygenator. Four rats were euthanized and connected post-mortem to a venous-arterial ECMO circulation for up to eight hours. Angiographic perfusion proofs, blood gas analyses and blood oxygenation calculations were performed. The mean preparation time for the ECMO system was 791 ± 29 s and sufficient organ perfusion could be maintained for 463 ± 26 min, proofed via angiographic imaging and a mean femoral arterial pressure of 43 ± 17 mmHg. A stable partial oxygen pressure, a 73% rise in arterial oxygen concentration and an exponentially increasing oxygen extraction ratio up to 4.75 times were shown. Considering the 3Rs, the established post-mortal ECMO perfusion rat model using surplus animals represents a promising alternative to models using live animals. Given the preserved organ perfusion, its use could be conceivable for various biomedical device testing.

Current knowledge gaps in extracorporeal respiratory support

Extracorporeal life support (ECLS) for acute respiratory failure encompasses veno-venous extracorporeal membrane oxygenation (V-V ECMO) and extracorporeal carbon dioxide removal (ECCO2R). V-V ECMO is primarily used to treat severe acute respiratory distress syndrome (ARDS), characterized by life-threatening hypoxemia or ventilatory insufficiency with conventional protective settings. It employs an artificial lung with high blood flows, and allows improvement in gas exchange, correction of hypoxemia, and reduction of the workload on the native lung. On the other hand, ECCO2R focuses on carbon dioxide removal and ventilatory load reduction ("ultra-protective ventilation") in moderate ARDS, or in avoiding pump failure in acute exacerbated chronic obstructive pulmonary disease. Clinical indications for V-V ECLS are tailored to individual patients, as there are no absolute contraindications. However, determining the ideal timing for initiating extracorporeal respiratory support remains uncertain. Current ECLS equipment faces issues like size and durability. Innovations include intravascular lung assist devices (ILADs) and pumpless devices, though they come with their own challenges. Efficient gas exchange relies on modern oxygenators using hollow fiber designs, but research is exploring microfluidic technology to improve oxygenator size, thrombogenicity, and blood flow capacity. Coagulation management during V-V ECLS is crucial due to common bleeding and thrombosis complications; indeed, anticoagulation strategies and monitoring systems require improvement, while surface coatings and new materials show promise. Moreover, pharmacokinetics during ECLS significantly impact antibiotic therapy, necessitating therapeutic drug monitoring for precise dosing. Managing native lung ventilation during V-V ECMO remains complex, requiring a careful balance between benefits and potential risks for spontaneously breathing patients. Moreover, weaning from V-V ECMO is recognized as an area of relevant uncertainty, requiring further research. In the last decade, the concept of Extracorporeal Organ Support (ECOS) for patients with multiple organ dysfunction has emerged, combining ECLS with other organ support therapies to provide a more holistic approach for critically ill patients. In this review, we aim at providing an in-depth overview of V-V ECMO and ECCO2R, addressing various aspects of their use, challenges, and potential future directions in research and development.

Survival outcomes and mobilization during venovenous extracorporeal membrane oxygenation: a retrospective cohort study

Introduction

Venovenous extracorporeal membrane oxygenation (V-V ECMO) can be considered in critically ill patient in severe pulmonary failure. However, the mobilization of patients on V-V ECMO can be challenging due to logistic and safety concerns. This study aimed to investigate whether 30 days survival was improved in patients who were mobilized during V-V ECMO support.

Methods

We conducted a retrospective cohort all-comer study that included all patients cannulated for V-V ECMO at a single center. Patients with a V-V ECMO duration below 24 h were excluded from the analysis. The patients were grouped based on the ICU mobility scale documented during V-V ECMO support. The primary endpoint was 30 days survival, and secondary endpoints included weaning from ECMO and mechanical ventilation, as well as hospital survival.

Results

A total of 343 patients were included in the study, with a median age of 56 years and 32% were female. Among them, 28% had chronic lung disease. The ICU mobilization scale ≥2 during ECMO was documented in 62/343 (18%) patients. There were no significant differences in age, gender and preexisting lung disease. Duration of ICU stay (13.1 vs. 15.6 days), time on ECMO (186 vs. 190 h) and mechanical ventilation (11.2 vs. 13.6 days) were slightly shorter in patients with ICU mobility scale <2 compared to those with ≥2 (all p = 0.0001). However, patients with ICU mobilization scale ≥2 showed significantly better 30 days survival (71.0 vs. 48.0%, OR 2.6 (1.5 to 4.8), p = 0.0012) compared to those with <2. In the ≥2 mobility scale group, a significantly higher number of patients were successfully weaned from the ventilator (61.3 vs. 46.6%, OR 1.8 (1.0 to 3.2), p = 0.049). A stronger correlation was observed between more intense mobilizations, such as being in a standing position (OR 5.0 (1.7 to 14.0), p = 0.0038), and higher 30 days survival.

Conclusion

The findings of this study suggest that active mobilization during V-V ECMO support is associated with improved 30 days survival and successful weaning from the respirator. Incorporating mobilization as part of the therapeutic approach during ECMO support may offer potential benefits for critically ill patients.

Demographics and Outcomes of Extracorporeal Membrane Oxygenation in COVID-19 Patients: National Database Analysis

INTRODUCTION

The effectiveness of extracorporeal membrane oxygenation (ECMO) in treating COVID-19 patients has been variable. To gain a better insight, we examined the outcomes of ECMO in COVID-19 patients using data from the 2020 National Inpatient Sample database.

METHODS

We analyzed data from adult hospital admissions where COVID-19 was the primary diagnosis. The primary outcome was all-cause inpatient mortality. Secondary outcomes were length of stay (LOS), cost, and discharge disposition.

RESULTS

We identified 1,048,025 COVID-19 admissions, of which 98,528 were on mechanical ventilation (MV), and only 1.8% received ECMO. In-hospital mortality of mechanically ventilated patients who received ECMO was 49%, compared to 59% with no ECMO (p < 0.001). ECMO treatment was associated with a reduced risk of mortality (HR = 0.67, p < 0.0001, CI 0.57-0.79) even after adjustment for confounders and other comorbidities. Patients on ECMO had significantly extended hospital stays and were more likely to be discharged to an acute care facility. Younger and male patients were more likely to receive ECMO treatment. Females had a lower mortality risk, while race and obesity were not associated with an increased risk of death.

CONCLUSION

ECMO treatment may offer survival benefits in severe COVID-19. Based on our findings, we suggest early ECMO treatment for patients with a high mortality risk.

Long-Term Physical, Cognitive, and Psychological Outcomes in Severe COVID-19 Patients Managed With Extracorporeal Membrane Oxygenation: A Prospective Study

Extracorporeal membrane oxygenation (ECMO) has been used in highly selected COVID-19 patients with severe respiratory failure. Scarce data exist on long-term outcomes of these patients. We performed a single-center prospective evaluation of consecutive COVID-19 ECMO patients successfully discharged from the intensive care unit between February 2020 and January 2022. Physical, cognitive and psychological outcome was assessed at 3, 6, and 12 months by in-person evaluation. All the 34 discharged patients (median age 49 years old) were alive at one year, and 25 of them were evaluated at the follow-up clinic. 67% of patients had muscle weakness, with improvement over time (p = 0.032). The percentage of patients able to return to work progressively increased, up to 86% at 1 year. 23% of patients experienced fatigue. Participation restriction improved over time for both physical (p = 0.050) and emotional (p = 0.005) problems. Cognitive impairment, anxiety, and depression occurred in 29%, 29%, and 23% of patients, respectively, with no changes over time. Health-related quality of life was good. In conclusion, COVID-19 ECMO patients suffer from significant long-term sequelae. However, multidimensional outcomes continued to improve over the follow-up time.

Preparation of Hyflon AD/Polypropylene Blend Membrane for Artificial Lung

A high-performance polypropylene hollow fiber membrane (PP-HFM) was prepared by using a binary environmentally friendly solvent of polypropylene as the raw material, adopting the thermally induced phase separation (TIPS) method, and adjusting the raw material ratio. The binary diluents were soybean oil (SO) and acetyl tributyl citrate (ATBC). The suitable SO/ATBC ratio of 7/3 was based on the size change of the L-L phase separation region in PP-SO/ATBC thermodynamic phase diagram. Through the characterization and comparison of the basic performance of PP-HFMs, it was found that with the increase of the diluent content in the raw materials, the micropores of outer surface of the PP-HFM became larger, and the cross section showed a sponge-like pore structure. The fluoropolymer, Hyflon ADx, was deposited on the outer surface of the hollow fiber membrane using a physical modification method of solution dipping. After modification, the surface pore size of the Hyflon AD40L modified membranes decreased; the contact angle increased to around 107°; the surface energy decreased to 17 mN·m^-1; and the surface roughness decreased to 17 nm. Hyflon AD40L/PP-HFMs also had more water resistance properties from the variation of wetting curve. For biocompatibility of the membrane, the adsorption capacity of the modified PP membrane for albumin decreased from approximately 1.2 mg·cm^-2 to 1.0 mg·cm^-2, and the adsorption of platelets decreased under fluorescence microscopy. The decrease in blood cells and protein adsorption in the blood prolonged the clotting time. In addition, the hemolysis rate of modified PP membrane was reduced to within the standard of 5%, and the cell survival rate of its precipitate was above 100%, which also indicated the excellent biocompatibility of fluoropolymer modified membrane. The improvement of hydrophobicity and blood compatibility makes Hyflon AD/PP-HFMs have the potential for application in membrane oxygenators.

Venovenous extracorporeal membrane oxygenation in COVID-19-related acute respiratory distress syndrome : What's the catch?

COVID-19 is still around, and in the most severe cases can rapidly progress to acute respiratory distress syndrome. When mechanical ventilation fails to improve oxygenation, we desperately shift our management to venovenous extracorporeal membrane oxygenation (vv-ECMO). In this opinion article, we discuss which patients are the most suitable to select for this technique, reiterate previous observations in acute respiratory distress syndrome, and the options for the patients judged not fitting for ECMO.

Veno-venous Extracorporeal Membrane Oxygenation: Anesthetic Considerations in Clinical Practice

CONTEXT

After the COVID-19 pandemic, multiple reviews have documented the success of veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Patients who experience hypoxemia but have normal contractility may be switched to veno-venous-ECMO (VV-ECMO).

PURPOSE

In this review, we present three protocols for anesthesiologists. Firstly, transesophageal echocardiography (TEE) aids in cannulation and weaning off inotropes and fluids. Our main objective is to assist in patient selection for the Avalon Elite single catheter, which is inserted into the right internal jugular vein and terminates in the right atrium. Secondly, we propose appropriate anticoagulant doses. We outline day-to-day monitoring protocols to prevent heparin-induced thrombocytopenia (HIT) or resistance. Once the effects of neuromuscular paralysis subside, sedation should be reduced. Therefore, we describe techniques that may prevent delirium from progressing into permanent cognitive decline.

METHODS

We conducted a PubMed search using the keywords VV-ECMO, TEE, Avalon Elite (Maquet, Germany), and quetiapine. We combined these findings with interviews conducted with nurses and anesthesiologists from two academic ECMO centers, focusing on anticoagulation and sedation.

RESULTS

Our qualitative evidence synthesis reveals how TEE confirms cannulation while avoiding right atrial rupture or low flows. Additionally, we discovered that typically, after initial heparinization, activated partial thromboplastin time (PTT) is drawn every 1 to 2 hours or every 6 to 8 hours once stable. Daily thromboelastograms, along with platelet counts and antithrombin III levels, may detect HIT or resistance, respectively. These side effects can be prevented by discontinuing heparin on day two and initiating argatroban at a dose of 1 μg/kg/min while maintaining PTT between 61 - 80 seconds. The argatroban dose is adjusted by 10 - 20% if PTT is between 40 - 60 or 80 - 90 seconds. Perfusionists assist in establishing protocols following manufacturer guidelines. Lastly, we describe the replacement of narcotics and benzodiazepines with dexmedetomidine at a dose of 0.5 to 1 μg/kg/hour, limited by bradycardia, and the use of quetiapine starting at 25 mg per day and gradually increasing up to 200 mg twice a day, limited by prolonged QT interval.

CONCLUSIONS

The limitation of this review is that it necessarily covers a broad range of ECMO decisions faced by an anesthesiologist. However, its main advantage lies in the identification of straightforward argatroban protocols through interviews, as well as the discovery, via PubMed, of the usefulness of TEE in determining cannula position and contractility estimates for transitioning from VA-ECMO to VV-ECMO. Additionally, we emphasize the benefits in terms of morbidity and mortality of a seldom-discussed sedation supplement, quetiapine, to dexmedetomidine.

Expert consensus statement on venovenous extracorporeal membrane oxygenation ECMO for COVID-19 severe ARDS: an international Delphi study

BACKGROUND

The high-quality evidence on managing COVID-19 patients requiring extracorporeal membrane oxygenation (ECMO) support is insufficient. Furthermore, there is little consensus on allocating ECMO resources when scarce. The paucity of evidence and the need for guidance on controversial topics required an international expert consensus statement to understand the role of ECMO in COVID-19 better. Twenty-two international ECMO experts worldwide work together to interpret the most recent findings of the evolving published research, statement formulation, and voting to achieve consensus.

OBJECTIVES

To guide the next generation of ECMO practitioners during future pandemics on tackling controversial topics pertaining to using ECMO for patients with COVID-19-related severe ARDS.

METHODS

The scientific committee was assembled of five chairpersons with more than 5 years of ECMO experience and a critical care background. Their roles were modifying and restructuring the panel's questions and, assisting with statement formulation in addition to expert composition and literature review. Experts are identified based on their clinical experience with ECMO (minimum of 5 years) and previous academic activity on a global scale, with a focus on diversity in gender, geography, area of expertise, and level of seniority. We used the modified Delphi technique rounds and the nominal group technique (NGT) through three face-to-face meetings and the voting on the statement was conducted anonymously. The entire process was planned to be carried out in five phases: identifying the gap of knowledge, validation, statement formulation, voting, and drafting, respectively.

RESULTS

In phase I, the scientific committee obtained 52 questions on controversial topics in ECMO for COVID-19, further reviewed for duplication and redundancy in phase II, resulting in nine domains with 32 questions with a validation rate exceeding 75% (Fig. 1). In phase III, 25 questions were used to formulate 14 statements, and six questions achieved no consensus on the statements. In phase IV, two voting rounds resulted in 14 statements that reached a consensus are included in four domains which are: patient selection, ECMO clinical management, operational and logistics management, and ethics.

CONCLUSION

Three years after the onset of COVID-19, our understanding of the role of ECMO has evolved. However, it is incomplete. Tota14 statements achieved consensus; included in four domains discussing patient selection, clinical ECMO management, operational and logistic ECMO management and ethics to guide next-generation ECMO providers during future pandemic situations.

Long-Term Follow-Up of Patients Needing Extracorporeal Membrane Oxygenation Following a Critical Course of COVID-19

INTRODUCTION

Severe respiratory failure is one of the most serious complications of coronavirus disease 2019 (COVID-19). In a small proportion of patients, mechanical ventilation fails to provide adequate oxygenation and extracorporeal membrane oxygenation (ECMO) is needed. The surviving individuals need long-term follow-up as it is not clear what their prognosis is.

AIM

To provide a complex clinical picture of patients during follow-up exceeding one year after the ECMO therapy due to severe COVID-19.

METHODS

All subjects involved in the study required ECMO in the acute stage of COVID-19. The survivors were followed-up for over one year at a specialized respiratory medical center.

RESULTS

Of the 41 patients indicated for ECMO, 17 patients (64.7% males) survived. The average age of survivors was 47.8 years, and the average BMI was 34.7 kg·m^-2. The duration of ECMO support was 9.4 days. A mild decrease in vital capacity (VC) and transfer factor (DLCO) was observed on the initial follow-up visit (82.1% and 60%, respectively). VC improved by 6.2% and by an additional 7.5% after 6 months and 1 year, respectively. DLCO improved by 21.1% after 6 months and remained stable after 1 year. Post-intensive care consequences included psychological problems and neurological impairment in 29% of patients; 64.7% of the survivors got vaccinated against SARS-CoV-2 within 12 months of hospitalization and 17.6% experienced reinfection with a mild course.

CONCLUSION

The COVID-19 pandemic has significantly increased the need for ECMO. Patients' quality of life after ECMO is temporarily significantly reduced but most patients do not experience permanent disability.

Extracorporeal Membrane Oxygenation Then and Now; Broadening Indications and Availability

Extracorporeal membrane oxygenation (ECMO) is a life support technology provided to children to support respiratory failure, cardiac failure, or cardiopulmonary resuscitation after failure of conventional management. Over the decades, ECMO has expanded in use, advanced in technology, shifted from experimental to a standard of care, and evidence supporting its use has increased. The expanded ECMO indications and medical complexity of children have also necessitated focused studies in the ethical domain such as decisional authority, resource allocation, and equitable access.

Simulators and Simulations for Extracorporeal Membrane Oxygenation: An ECMO Scoping Review

High-volume extracorporeal membrane oxygenation (ECMO) centers generally have better outcomes than (new) low-volume ECMO centers, most likely achieved by a suitable exposure to ECMO cases. To achieve a higher level of training, simulation-based training (SBT) offers an additional option for education and extended clinical skills. SBT could also help to improve the interdisciplinary team interactions. However, the level of ECMO simulators and/or simulations (ECMO sims) techniques may vary in purpose. We present a structured and objective classification of ECMO sims based on the broad experience of users and the developer for the available ECMO sims as low-, mid-, or high-fidelity. This classification is based on overall ECMO sim fidelity, established by taking the median of the definition-based fidelity, component fidelity, and customization fidelity as determined by expert opinion. According to this new classification, only low- and mid-fidelity ECMO sims are currently available. This comparison method may be used in the future for the description of new developments in ECMO sims, making it possible for ECMO sim designers, users, and researchers to compare accordingly, and ultimately improve ECMO patient outcomes.

Comparative outcomes of extracorporeal membrane oxygenation for COVID-19 delivered in experienced European centres during successive SARS-CoV-2 variant outbreaks (ECMO-SURGES): an international, multicentre, retrospective cohort study

BACKGROUND

To inform future research and practice, we aimed to investigate the outcomes of patients who received extracorporeal membrane oxygenation (ECMO) for acute respiratory distress syndrome (ARDS) due to different variants of SARS-CoV-2.

METHODS

This retrospective study included consecutive adult patients with laboratory-confirmed SARS-CoV-2 infection who received ECMO for ARDS in 21 experienced ECMO centres in eight European countries (Austria, Belgium, England, France, Germany, Italy, Portugal, and Spain) between Jan 1, 2020, and Sept 30, 2021. We collected data on patient characteristics, clinical status, and management before and after the initiation of ECMO. Participants were grouped according to SARS-CoV-2 variant (wild type, alpha, delta, or other) and period of the pandemic (first [Jan 1-June 30] and second [July 1-Dec 31] semesters of 2020, and first [Jan 1-June 30] and second [July 1-Sept 30] semesters of 2021). Descriptive statistics and Kaplan-Meier survival curves were used to analyse evolving characteristics, management, and patient outcomes over the first 2 years of the pandemic, and independent risk factors of mortality were determined using multivariable Cox regression models. The primary outcome was mortality 90 days after the initiation of ECMO, with follow-up to Dec 30, 2021.

FINDINGS

ECMO was initiated in 1345 patients. Patient characteristics and management were similar for the groups of patients infected with different variants, except that those with the delta variant had a younger median age and less hypertension and diabetes. 90-day mortality was 42% (569 of 1345 patients died) overall, and 43% (297/686) in patients infected with wild-type SARS-CoV-2, 39% (152/391) in those with the alpha variant, 40% (78/195) in those with the delta variant, and 58% (42/73) in patients infected with other variants (mainly beta and gamma). Mortality was 10% higher (50%) in the second semester of 2020, when the wild-type variant was still prevailing, than in other semesters (40%). Independent predictors of mortality were age, immunocompromised status, a longer time from intensive care unit admission to intubation, need for renal replacement therapy, and higher Sequential Organ Failure Assessment haemodynamic component score, partial pressure of arterial carbon dioxide, and lactate concentration before ECMO. After adjusting for these variables, mortality was significantly higher with the delta variant than with the other variants, the wild-type strain being the reference.

INTERPRETATION

Although crude mortality did not differ between variants, adjusted risk of death was highest for patients treated with ECMO infected with the delta variant of SARS-CoV-2. The higher virulence and poorer outcomes associated with the delta strain might relate to higher viral load and increased inflammatory response syndrome in infected patients, reinforcing the need for a higher rate of vaccination in the population and updated selection criteria for ECMO, should a new and highly virulent strain of SARS-CoV-2 emerge in the future. Mortality was noticeably lower than in other large, multicentre series of patients who received ECMO for COVID-19, highlighting the need to concentrate resources at experienced centres.

FUNDING

None.