Are Nonconventional Ventilators Associated with Mortality in Covid Ards? A Multicenter Study

INTRODUCTION: Many first wave COVID ARDS patients who were intubated spent a prolonged time on non-conventional ventilators (NCV) (e.g. transport devices, BiPAP machines) that are not intended for long-term use. The impact of prolonged NCV use on mortality is unknown. We hypothesized that time spent on NCV, compared to conventional ventilators (CV), is associated with higher mortality among COVID ARDS patients. METHOD(S): This is a retrospective multicenter study of our health system's COVID ARDS database from 03/01/20 - 04/30/20. We included intubated adults with COVID ARDS, mechanically ventilated on either NCV or CV. We excluded patients who switched between ventilator types, palliative extubations, and deaths within 24 hours of intubation. Baseline demographics and confounders were recorded. The primary outcome was 90 day mortality, and secondary outcomes were 3 and 28 day mortality. The effect of time spent on a NCV on 90 day mortality was modeled using logistic regression while controlling for confounders. The effect of time on NCV on 90 day mortality was quantified as an odds ratio (OR) and compared to the null using the Wald test. This was repeated for 3 and 28 day mortality. RESULT(S): Of 2094 patients who met inclusion criteria, we excluded 113 deaths within 24 hours, 500 ventilator switches, and 426 missing data points, for n=1055. Mean age was 65 years, 317 (30%) female, and 384 (36%) Caucasian. NCVs were used in 345 (33%) cases. Median time intubated was 9.8 days for NCV and 11 days for CV groups. Mean adjusted tidal volumes (ATV) were 6.8 for NCV and 6.6 ml/kg for CV. Overall unadjusted 90, 3 and 28 day mortality were 68%, 9% and 62%, respectively. Charlson Comorbidity Index (CCI), BMI, respiratory compliance (RC), ATV, P/F ratio, time averaged PEEP, time on vasopressors, and steroid use were controlled for. CCI and vasopressors correlated with higher mortality (p< 0.05). RC, P/F and PEEP correlated with lower mortality (p< 0.05). Time on NCV did not correlate with 90 day (OR=1.27, p=0.12) or 3 day mortality (OR=1.28, p=0.31) and correlated with increased 28 day mortality (OR = 1.5, p = 0.006). CONCLUSION(S): Among patients with COVID ARDS in early 2020, mechanical ventilation with NCVs was associated with increased adjusted mortality at 28 days but not at 3 and 90 days compared with CVs.

Expanding COVID-19 Vaccine Availability: Role for Combined Orthogonal Serology Testing (COST)

BACKGROUND: The persisting Coronavirus disease 2019 (COVID-19) pandemic and limited vaccine supply has led to a shift in global health priorities to expand vaccine coverage. Relying on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) molecular testing alone cannot reveal the infection proportion, which could play a critical role in vaccination prioritization. We evaluated the utility of a combination orthogonal serological testing (COST) algorithm alongside RT-PCR to quantify prevalence with the aim of identifying candidate patient clusters to receive single and/or delayed vaccination. METHODS: We utilized 108,505 patients with suspected COVID-19 in a retrospective analysis of SARS-CoV-2 RT-PCR vs. IgG-nucleocapsid (IgG_NC) antibody testing coverage in routine practice for the estimation of prevalence. Prospectively, an independent cohort of 21,388 subjects was simultaneously tested by SARS-CoV-2 RT-PCR and IgG_NC to determine the prevalence. We used 614 prospective study subjects to assess the utility of COST (IgG_NC, IgM-spike (IgM_SP), and IgG-spike (IgG_SP)) in establishing the infection proportion to identify a single-dose vaccination cohort. RESULTS: Retrospectively, we observed a 6.3% (6871/108,505) positivity for SARS-CoV-2 RT-PCR, and only 2.3% (2533/108,505) of cases had paired IgG_NC serology performed. Prospectively, IgG_NC serology identified twice the number of COVID-positive cases in relation to RT-PCR alone. COST further increased the number of detected positive cases: IgG_NC+ or IgM_SP+ (18.0%);IgG_NC+ or IgG_SP+ (23.5%);IgM_SP+ or IgG_SP+ (23.8%);and IgG_NC+ or IgM_SP+ or IgG_SP+ (141/584 = 24.1%). CONCLUSION: COST may be an effective tool for the evaluation of infection proportion and thus could define a cohort for a single dose and/or delayed vaccination.

Role of veno-venous extracorporeal carbon dioxide removal in coronavirus disease 2019 associated acute respiratory distress syndrome

Introduction: Standard management for acute respiratory distress syndrome secondary to Coronavirus disease 2019 (COVID-19) includes low tidal volume lung-protective mechanical ventilation, paralytics and prone positioning. Permissive hypercapnia is allowed to reduce the risk of barotrauma. Despite stabilization of oxygenation, some patients develop progressive respiratory acidosis. This may be due to a combination of mucus plugging and microthrombi in the lungs. Methods: We describe the use of veno-venous extracorporeal carbon dioxide removal (ECCO2R) in three patients with COVID-19 associated severe ARDS and refractory. Results: Patient 1 showed improvement in respiratory acidosis following initiation of ECCO2R, however after 24 hours of stabilization he developed progressive hypoxemia and cardiac arrest without return of spontaneous circulation. Patient 2 showed improvement in respiratory acidosis following initiation of ECCO2R and remained stable for several days before developing progressive hypoxemia requiring veno-venous extracorporeal membrane oxygenation (V-V ECMO) support. He was successfully weaned off V-V ECMO after two weeks. Patient 3 also remained stable on ECCO2R support for a week before developing refractory hypoxemia and cardiac arrest without return of spontaneous circulation. Conclusion: In severe COVID-19 ARDS on optimal lung-protective ventilation, progressive hypoxemia may lag behind hypercapnia, rendering carbon dioxide removal alone insufficient. We suggest that patients who develop progressive respiratory acidosis despite maximum optimization of lung-protective ventilation should be considered for V-V ECMO support rather than ECCO2R alone.