Clinical Mortality Review in a Large COVID-19 Cohort
Authors: Jarrett Mark P. , Schultz Susanne E. , Lyall Julie S. , Wang Jason J. , Stier Lori , De Geronimo Marcella , Nelson Karen L. 
Published: August 2020

Background

Northwell Health (Northwell), an integrated health system in New York, treated more than 15000 inpatients with coronavirus disease (COVID-19) at the US epicenter of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. We describe the demographic characteristics of COVID-19 mortalities, observation of frequent rapid response teams (RRT)/cardiac arrest (CA) calls for non-intensive care unit (ICU) patients, and factors that contributed to RRT/CA calls.

Methods

A team of registered nurses reviewed medical records of inpatients who tested positive for SARS-CoV-2 via polymerase chain reaction (PCR) before or on admission and died between March 13 (first Northwell inpatient expiration) and April 30, 2020 at 15 Northwell hospitals. Findings for these patients were abstracted into a database and statistically analyzed.

Findings

Of 2634 COVID-19 mortalities, 56.1% had oxygen saturation levels greater than or equal to 90% on presentation and required no respiratory support. At least one RRT/CA was called on 42.2% of patients at a non-ICU level of care. Before the RRT/CA call, the most recent oxygen saturation levels for 76.6% of non-ICU patients were at least 90%. At the time RRT/CA was called, 43.1% had an oxygen saturation less than 80%.

Interpretation

This study represents one of the largest cohorts of reviewed mortalities that also captures data in non-structured fields. Approximately 50% of deaths occurred at a non-ICU level of care, despite admission to the appropriate care setting with normal staffing. The data imply a sudden, unexpected deterioration in respiratory status requiring RRT/CA in a large number of non-ICU patients. Patients admitted to a non-ICU level of care suffer rapid clinical deterioration, often with a sudden decrease in oxygen saturation. These patients could benefit from additional monitoring (eg, continuous central oxygenation saturation), although this approach warrants further study.

Funding

National Institute on Aging and the National Library of Medicine of the National Institutes of Health.

RESEARCH IN CONTEXT

Evidence before the study

The world first learned of SARS-CoV-2 through a landmark study published by the Lancet in January 2020. Early evidence was limited due to the novel nature of the virus, clinician inexperience in treating COVID-19, small sample size of primarily hospital inpatients in early observational studies, use of structured datasets for data collection, and early and evolving treatment guidelines. We collected evidence from leading medical journals from January 2020 through June 2020 that primarily describe the clinical characteristics of COVID-19 (eg, patient age, sex, and comorbidities) as well as the different approaches to treatment that were being used. Our search consisted of real-time publications as they became available. Analyzing the characteristics of patients who died can help to define the clinical nature of COVID-19 and potentially suggest new care protocols.

Added value of this study

Unlike prior research, our study represents one of the largest cohorts of COVID-19 mortalities abstracted from both structured and unstructured fields in the medical record using data collected during the surge of infections in the New York metropolitan area in March through April 2020. Our study identified an unusual pattern of respiratory decompensation in patients who presented to the hospital with acceptable oxygen saturation levels and were therefore admitted to a non-ICU setting for care. Through our unique analysis, we identified a cohort of patients who experienced a rapid response team/cardiac arrest call after a sudden and unexpected decrease in their oxygenation saturation levels.

Implications of available evidence

Our findings, based on over 2600 inpatient mortalities, suggest that there is a subpopulation of patients who are admitted to a non-ICU setting where continuous oxygenation saturation monitoring is not a standard, but may be warranted. Further research is needed to understand which patients are at highest risk for mortality, due to age and comorbidities, and the implications of continuous monitoring on mortality rates. This finding is relevant to a wide audience of national and international health care providers.