Outcomes of Interfacility VV-Extracorporeal Membrane Oxygenation Transfers: A Multicenter Study.

As the availability of extracorporeal membrane oxygenation (ECMO) expands, so has the need for interfacility transfer to ECMO centers. However, the impact of these transfers is unknown. We hypothesized that interfacility transfers would be associated with increased complications and mortality. This retrospective cohort study includes adult patients treated with venovenous (VV) ECMO at all four adult ECMO centers comprising our statewide registry. Complications, mortality, ECMO duration, length of stay, and disposition were compared based on cannulation at an ECMO center versus outside hospital and transferred by air versus ground after adjusting for baseline covariates/parameters. The study included 420 adult patients, 36% of whom were cannulated at an outside institution before transfer. Of these, 63% were transported by ground and the remainder by air. Risk adjusted logistic regression revealed similar odds of mortality between those cannulated at ECMO centers versus referring hospital and then transported (odds ratio [OR] = 0.77, confidence interval [CI] = 0.49-1.22). This study supports the practice of interfacility ECMO transfer.

Use of Venovenous Extracorporeal Membrane Oxygenation in Patients With Acute Respiratory Distress Syndrome Caused by Fungal Pneumonia.

Background: Patients with fungal pneumonias sometimes progress to acute respiratory distress syndrome (ARDS). Mortality has been reported as high as 60% to 90% in this group. Venovenous extracorporeal membrane oxygenation (VV-ECMO) can be used to support such patients, however, outcomes are not well understood. Patients and Methods: This was a retrospective study across the four adult ECMO centers in Minnesota for one decade (2012-2022). The outcomes of interest were duration of ECMO, survival rate, and complications. Data were extracted from the electronic medical record and analyzed using descriptive statistics. Results: Fungal pneumonia was the etiology of ARDS in 22 of 422 (5%) adults supported with VV-ECMO during the 10-year study period. Median patient age was 43 years (interquartile range [IQR], 35-56) and 68% were male. By type of fungal infection, 16 (72%) had blastomycosis, five (22%) had pneumocystis, and one (5%) had cryptococcus. Of the 16 patients with blastomycosis two were immunosuppressed whereas all five of the pneumocystis patients were immunosuppressed. The overall survival rate was 73%; most patients with blastomycosis (67%) and pneumocystis (80%) survived to hospital discharge. The duration of ECMO support was greater for the pneumocystis group (median, 30 days; IQR, 21-43) compared with blastomycosis (median, 10 days; IQR, 8-18). Conclusions: Our findings support the use of VV-ECMO for ARDS caused by fungal pneumonias in select immunocompetent and immunocompromised patients. Although survival was high, patients with pneumocystis required longer ECMO runs.

Evaluation of Minnesota Score in the Allocation of Venovenous Extracorporeal Membrane Oxygenation During Resource Scarcity.

Background: In this study, we evaluate the previously reported novel Minnesota Score for association with in-hospital mortality and allocation of venovenous extracorporeal membrane oxygenation in patients with acute respiratory distress syndrome with or without SARS-CoV-2 pneumonia. Methods: This was a retrospective cohort study across four extracorporeal membrane oxygenation centers in Minnesota. Logistic regression was used to assess the relationship between the scores and in-hospital mortality, duration of ECMO cannulation, and discharge disposition. Priority groups were established statistically by maximizing the sum of sensitivity and specificity and compared to the previous qualitatively established priority groups. Results: Of 124 patients included in the study, 38% were treated for COVID-19 acute respiratory distress syndrome. The median age was 48 years, and 73% were male. The in-hospital mortality rate was 38%. The Minnesota Score was significantly associated with in-hospital mortality only (OR 1.13, p=0.02). Statistically determined cut points were similar to qualitative cut points. SARS-CoV-2 status did not change the findings. Conclusions: In our patient cohort, the Minnesota Score is associated with increased mortality. With further validation, proposed priority groups could be utilized for allocation of ECMO in times of increasing scarcity.

Increasing Mortality in Venovenous Extracorporeal Membrane Oxygenation for COVID-19-Associated Acute Respiratory Distress Syndrome.

OBJECTIVES: Determine the factors associated with mortality in venovenous extracorporeal membrane oxygenation (V-V ECMO) patients with COVID-19 infection and provide an updated report of clinical outcomes for patients treated with V-V ECMO for COVID-19 in Minnesota. DESIGN: Multicenter prospective observational study. SETTING: The four adult Extracorporeal Life Support Organization-certified Centers of Excellence in Minnesota. PATIENTS: A total of 100 patients treated with V-V ECMO for COVID-19-associated acute respiratory distress syndrome (ARDS) from March 2020 to May 2021. INTERVENTIONS: Not applicable. MEASUREMENTS AND MAIN RESULTS: The primary outcome was 60-day survival for patients treated with V-V ECMO for COVID-19. Outcomes of patients treated from November 2020 to May 2021(cohort 2) were compared with data from a previous cohort of patients, collected from March 2020 to October 2020 (cohort 1). The data from both cohorts were merged into a single dataset (Combined Cohort). Survival on V-V ECMO due to COVID-19-associated ARDS significantly decreased after October 2020 (63% vs 41%; p = 0.026). The median interval from hospital admission to V-V ECMO cannulation was significantly associated with 60-day mortality (10 d [6-14 d] in nonsurvivors vs 7 d [4-9 d] in survivors; p = 0.001) in the Combined Cohort and was also significantly longer in cohort 2 than cohort 1 (10 d [7-14 d] vs 6 d [4-10 d]; p < 0.001). In the Combined Cohort, the 60-day survival for patients who did not receive steroids was 86% (n = 12) versus 45% (n = 39) for patients who received at least one dose of steroids (p = 0.005). CONCLUSIONS: There was a significant increase in mortality for patients treated with V-V ECMO for COVID-19-associated ARDS in cohort 2 compared with cohort 1. Further research is required to determine the cause of the worsening trend in mortality.

Risk Factors of Mortality for Patients Receiving Venovenous Extracorporeal Membrane Oxygenation for COVID-19 Acute Respiratory Distress Syndrome.

Background: Venovenous extracorporeal membrane oxygenation (VV-ECMO) for select adults with severe acute respiratory distress syndrome (ARDS) cause by coronavirus disease 2019 (COVID-19) infection is a guideline-supported therapy with associated hospital survival of 62%-74%, similar to expected survival with VV-ECMO for other indications. However, ECMO is a resource-heavy intervention, and these patients often require long ECMO runs and prolonged intensive care unit (ICU) care. Identifying factors associated with mortality in VV-ECMO patients with COVID-19 infection can inform the evaluation of ECMO candidates as well as prognostication for those patients on prolonged VV-ECMO. Patients and Methods: This was a retrospective cohort study that included all patients who received either VV- or venoarteriovenous (VAV)-ECMO at one of four ECMO Centers of Excellence in the state of Minnesota between March 1, 2020 and November 1, 2020. The primary outcome was 60-day survival. Secondary outcomes were hospital complications, infectious complications, and complications from ECMO. Results: There were 46 patients who met criteria during this study period and 30 survived to 60-day follow-up (65.2%). Prior to cannulation, older patient age (55.5 in non-survivors vs. 49.1 years in survivors; p = 0.03), lower P/F ratio (62.1 vs. 76.2; p = 0.04), and higher sequential organ failure assessment (SOFA) score (8.1 vs. 6.6; p = 0.02) were identified as risk factors for mortality. After ECMO cannulation, increased mortality was associated with increased number of antibiotic days (25.9 vs. 14.5; p = 0.04), increased number of transfusions (23.9 vs. 9.9; p = 0.03), elevated white blood cell (WBC) count at post-ECMO days one through three, elevated D-dimer at post-ECMO day 21-27, and decreased platelet count from post-ECMO days 14 and onward using univariable analysis. Conclusions: Multiple markers of infection including leukocytosis, thrombocytopenia, and increased antibiotic days are associated with increased mortality in patients placed on VV-ECMO for COVID-19 infection and subsequent ARDS. Knowledge of these factors may assist with determining appropriate candidates for this limited resource as well as direct goals of care in prolonged ECMO courses.

Treatment of Severe Hypercapnic Respiratory Failure Caused by SARS-CoV-2 Lung Injury with ECCO2R Using the Hemolung Respiratory Assist System.

Acute respiratory distress syndrome (ARDS) due to COVID-19 leads to a high rate of mortality in the intensive care unit (ICU). A lung-protective mechanical ventilation strategy using low tidal volumes is a cornerstone to management, but uncontrolled hypercapnia is a life-threatening consequence among severe cases. A mechanism to prevent progressive hypercapnia may offset hemodynamic instability among patients who develop hypercapnia. We present the case of a woman in her mid-60's with severe acute hypercapnic respiratory failure secondary to COVID-19 pneumonia who was successfully treated with early implementation of lung-protective ventilation facilitated by extracorporeal carbon dioxide removal (ECCO2R). This patient's multiple comorbid conditions included obesity, hypertension, type 2 diabetes mellitus, and hypercholesterolemia. On her fifth day of admission at the referring hospital, her worsening hypoxemia prompted endotracheal intubation during which she developed pneumothorax. She was transferred to our institution for advanced care where upon arrival, she had profound hypercapnia and respiratory acidosis. She met the criteria for treatment with an investigational ECCO2R device (Hemolung Respiratory Assist System) available through FDA Emergency Use Authorization. ECCO2R is similar to extracorporeal membrane oxygenation (ECMO) but operates at much lower blood flows (350-550 mL/min) through a smaller 15.5 French central venous catheter. Standard heparinization was provided intravenously to achieve appropriate levels of anticoagulation during ECCO2R therapy. Unlike ECMO, ECCO2R does not provide clinically meaningful oxygenation but is simpler to implement and manage. The use of ECCO2R successfully corrected and controlled the patient's hypercapnia and acidosis and enabled meaningful reductions in ventilator tidal volumes, respiratory rates, and mean airway pressures. The patient was weaned from ECCO2R after 17 days and from mechanical ventilation 10 days later. With low tidal volume ventilation facilitated by expeditious implementation of ECCO2R, the patient survived to discharge despite her many risk factors for a poor outcome and an extended duration of invasive mechanical ventilation.

Physiologic Improvement in Respiratory Acidosis Using Extracorporeal Co2 Removal With Hemolung Respiratory Assist System in the Management of Severe Respiratory Failure From Coronavirus Disease 2019.

OBJECTIVES: About 15% of hospitalized coronavirus disease 2019 patients require ICU admission, and most (80%) of these require invasive mechanical ventilation. Lung-protective ventilation in coronavirus disease 2019 acute respiratory failure may result in severe respiratory acidosis without significant hypoxemia. Low-flow extracorporeal Co2 removal can facilitate lung-protective ventilation and avoid the adverse effects of severe respiratory acidosis. The objective was to evaluate the efficacy of extracorporeal Co2 removal using the Hemolung Respiratory Assist System in correcting severe respiratory acidosis in mechanically ventilated coronavirus disease 2019 patients with severe acute respiratory failure. DESIGN: Retrospective cohort analysis of patients with coronavirus disease 2019 mechanically ventilated with severe hypercapnia and respiratory acidosis and treated with low-flow extracorporeal Co2 removal. SETTING: Eight tertiary ICUs in the United States. PATIENTS: Adult patients supported with the Hemolung Respiratory Assist System from March 1, to September 30, 2020. INTERVENTIONS: Extracorporeal Co2 removal with Hemolung Respiratory Assist System under a Food and Drug Administration emergency use authorization for coronavirus disease 2019. MEASUREMENTS AND MAIN RESULTS: The primary outcome was improvement in pH and Paco2 from baseline. Secondary outcomes included survival to decannulation, mortality, time on ventilator, and adverse events. Thirty-one patients were treated with Hemolung Respiratory Assist System with significant improvement in pH and Pco2 in this cohort. Two patients experienced complications that prevented treatment. Of the 29 treated patients, 58% survived to 48 hours post treatment and 38% to hospital discharge. No difference in age or comorbidities were noted between survivors and nonsurvivors. There was significant improvement in pH (7.24 ± 0.12 to 7.35 ± 0.07; p < 0.0001) and Paco2 (79 ± 23 to 58 ± 14; p < 0.0001) from baseline to 24 hours. CONCLUSIONS: In this retrospective case series of 29 patients, we have demonstrated efficacy of extracorporeal Co2 removal using the Hemolung Respiratory Assist System to improve respiratory acidosis in patients with severe hypercapnic respiratory failure due to coronavirus disease 2019.

The Use of Venovenous Extracorporeal Membrane Oxygenation in COVID-19 Infection: One Region's Comprehensive Experience.

Severe acute respiratory distress syndrome (ARDS) unresponsive to conventional intensive care unit (ICU) management is an accepted indication for venovenous extracorporeal membrane oxygenation (V-V ECMO) support. The frequency with which patients with coronavirus disease 2019 (COVID-19) pneumonia are selected for V-V ECMO has not been described. This was a cohort study including all patients placed on either V-V ECMO or venoarteriovenous ECMO at the four adult ECMO Centers of Excellence. Primary outcomes evaluated were survival to decannulation from the ECMO circuit, survival to discharge, and 60-day survival. Secondary outcomes were hospital length of stay (LOS), ICU LOS, length of ECMO cannulation, and length of intubation. During the study period, which corresponded to the first surge in COVID-19 hospitalizations in Minnesota, 35 patients with ARDS were selected for V-V ECMO support out of 1,849 adult ICU patients with COVID-19 infection in the state (1.9% incidence; 95% CI, 1.3-2.6%). This represents 46 (95% CI, 34-61) expected V-V ECMO patients per 100,000 confirmed positive cases of COVID-19. Twenty-six of the 35 patients (74.3%) supported with V-V ECMO survived to 60-day post-ECMO decannulation. Recent studies have demonstrated ongoing success rescuing patients with severe ARDS in COVID-19 infection. Our data add to the support of ECMO and the consideration for encouraging cooperation among regional ECMO centers to ensure access to this highest level of care. Finally, by evaluating all the patients of a single region, we estimate overall need for this resource intensive intervention based on the overall number of COVID-19 cases and ICU admissions.

Regional Planning for Extracorporeal Membrane Oxygenation Allocation During Coronavirus Disease 2019.

Health systems confronting the coronavirus disease 2019 (COVID-19) pandemic must plan for surges in ICU demand and equitably distribute resources to maximize benefit for critically ill patients and the public during periods of resource scarcity. For example, morbidity and mortality could be mitigated by a proactive regional plan for the triage of mechanical ventilators. Extracorporeal membrane oxygenation (ECMO), a resource-intensive and potentially life-saving modality in severe respiratory failure, has generally not been included in proactive disaster preparedness until recently. This paper explores underlying assumptions and triage principles that could guide the integration of ECMO resources into existing disaster planning. Drawing from a collaborative framework developed by one US metropolitan area with multiple adult and pediatric extracorporeal life support centers, this paper aims to inform decision-making around ECMO use during a pandemic such as COVID-19. It also addresses the ethical and practical aspects of not continuing to offer ECMO during a disaster.

Use of expiratory change in bladder pressure to assess expiratory muscle activity in patients with large respiratory excursions in central venous pressure.

BACKGROUND: Expiratory muscle activity may cause the end-expiratory central venous pressure (CVP) to greatly overestimate right atrial transmural pressure. METHODS: We recorded CVP and expiratory change in intra-abdominal pressure (ΔIAP) in 39 patients who had a respiratory excursion in CVP from end-expiration to end-inspiration (CVP(ee)-CVP(ei)) ≥ 8 mmHg. Uncorrected CVP was measured at end-expiration, and corrected CVP was calculated as uncorrected CVP-ΔIAP. In 13 patients measurements were repeated during relaxed breathing. RESULTS: The CVP(ee)-CVP(ei) was 15.2 ± 6.3 mmHg (range 8-34 mmHg), and ΔIAP was 7.4 ± 6.0 mmHg (range 0-30 mmHg). Uncorrected CVP was 18.3 ± 6.1 mmHg, and corrected CVP was 10.9 ± 3.9 mmHg. There was a significant positive correlation between CVP(ee)-CVP(ei) and ΔIAP (r = 0.814). However, some patients with a large CVP(ee)-CVP(ei) had negligible ΔIAP. In a subset of 13 patients with active expiration who had a relaxed CVP tracing available for comparison, the difference between uncorrected CVP and relaxed CVP was much greater than the difference between corrected CVP and relaxed CVP (7.3 ± 3.0 vs. 1.1 ± 0.7 mmHg, p < 0.001). CONCLUSION: Patients with large respiratory excursions in CVP often have significant expiratory muscle activity that will cause their CVP to overestimate transmural right atrial pressure. The magnitude of expiratory muscle activity can be assessed by measuring ΔIAP. Subtracting ΔIAP from the end-expiratory CVP usually provides a reasonable estimate of the CVP that would be obtained if exhalation were passive.