Estimation of Excess Mortality Resulting from Use of a Ventilator Triage Protocol Under Sars-CoV-2 Pandemic Surge Conditions

Abstract

Rationale: COVID-19 hospitalizations continue to surge rapidly throughout the world. Given the high morbidity and mortality and prolonged duration of illness experienced by patients with respiratory failure due to COVID-19, shortages of ventilators are expected. In New York State, the Crisis Standards of Care guidelines were codified by the New York State Taskforce on Life and the Law in the 2015 Ventilator Triage Guidelines (NYS guidelines). These guidelines outline clinical criteria for triage, including exclusion criteria and stratification of patients using the Sequential Organ Failure Assessment (SOFA) score. We aimed to estimate the excess mortality that would be associated with implementation of triage processes using this protocol. Methods: We included all 5,028 patients who were admitted with COVID-19 in three acute care hospitals at a single academic medical center in the Bronx from March 1, 2020 to May 27, 2020 during the peak of the pandemic surge in New York City. Importance sampling was used to estimate the likelihood of patient trajectories under the NYS guidelines and estimate survival rates. Pessimistic and optimistic estimations were derived to account for potential unobserved confounders. Overall estimated survival was then calculated over a range of hypothetical ventilator shortages (e.g. if it has not been possible to acquire the additional ventilators that were procured in the Spring) from 85-100% availability of the total ventilator capacity of these facilities. Results: The average age of the sample was 64.2 (SD 16.2) and 47% were female. The observed survival rate was 74.16%. A total of 721 patients (14%) required mechanical ventilation during admission. If there has been a ventilator shortfall with ventilator capacity at 85% and the NYS guidelines were enacted in this setting, the estimated survival would be between 70.3% (pessimistic estimation) and 71.5% (optimistic estimation) (Figure 1). Conclusions: A shortfall of ventilators at 85% ventilator capacity requiring implementation of the NYS guidelines triage protocol would have resulted in 2.7-3.9% excess mortality in hospitalized patients with COVID-19 during the pandemic surge, or 134-194 additional deaths. This study is limited by the exclusion of COVID-19 negative patients, who would be in the triage pool in an actual triage situation. Future directions include using this data set to compare NYS guideline performance to other triage strategies including first-come first-served and random allocation to better understand the utility of SOFA score-based triage strategies.