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 lifesaving 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 decisionmaking 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.

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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.

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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 C o 2 removal can facilitate lung-protective ventilation and avoid the adverse effects of severe respiratory acidosis. The objective was to evaluate the efficacy of extracorporeal C o 2 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 C o 2 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 C o 2 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 Pa co 2 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 P co 2 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 Pa co 2 (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 C o 2 removal using the Hemolung Respiratory Assist System to improve respiratory acidosis in patients with severe hypercapnic respiratory failure due to coronavirus disease 2019.

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.

BACKGROUND: The value of heliox (helium-oxygen mixture) for patients with severe air-flow obstruction is uncertain. The purpose of this study was to determine whether heliox could reduce the degree of hyperinflation and hypercapnia in mechanically ventilated patients with severe airflow obstruction. METHODS: This was a single-center, prospective observational study conducted in a medical ICU of an academic medical center. We assessed the impact of heliox (65-70% helium, 30 -35% oxygen) on airway pressures and arterial blood gases of 13 subjects undergoing mechanical ventilation for severe asthma (n ‫؍‬ 8) or exacerbation of COPD (n ‫؍‬ 5). RESULTS: As compared with ventilation with air-O 2 , heliox resulted in a reduction in peak airway pressure (54.1 ؎ 12.6 cm H 2 O vs 47.9 ؎ 10.8 cm H 2 O, P < .001) and P aCO 2 (64.3 ؎ 14.9 mm Hg vs 62.3 ؉ 15.1 mm Hg, P ‫؍‬ .01). In contrast, there was no change in plateau pressure (25.3 ؎ 5.5 cm H 2 O vs 25.8 ؎ 5.6 cm H 2 O, P ‫؍‬ .14) or total PEEP (13.4 ؎ 3.8 cm H 2 O vs 13.3 ؎ 4.1 cm H 2 O, P ‫؍‬ .79) in response to heliox. CONCLUSIONS: In mechanically ventilated subjects with severe air-flow obstruction, administration of heliox had no effect on indices of dynamic hyperinflation (plateau pressure and total PEEP) and resulted in only a small reduction in P aCO 2 .

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.