40 Trajectories of Vital Signs and Risk of Cardiac Arrest in the Emergency Department

Abstract

Early recognition and prevention have been added as the first link in the Chain of Survival for in-hospital cardiac arrest (IHCA). However, little is known about the trajectories of vital signs prior to IHCA, which could inform the heterogeneous processes preceding this devastating event. Therefore, using group- based trajectories modeling of longitudinal vital sign data in the emergency department (ED), we aimed to identify clinically relevant subphenotypes at high risk of IHCA in the ED. This retrospective cohort study used electronic clinical warehouse data from a tertiary medical center with approximately 100, 000 ED visits per year. We retrieved data from 733, 398 ED visits over a 7-year period. We selected one ED visit per person and excluded out-of-hospital cardiac arrest, patients aged less than 18 years, or those who had less than three vital-sign measurements. Patient demographics, triage data, vital signs (systolic blood pressure [SBP], heart rate [HR], body temperature, respiratory rate, oxygen saturation), selected laboratory test results, and IHCA status were also retrieved. Group-based trajectory modeling was performed to identify vital-sign trajectory groups, and patient characteristics and IHCA status were compared between the groups. A total of 37, 697 adult ED patients were included. Of them, 145 (0.4%) developed IHCA. Three to four trajectory groups per vital sign were identified, and the following five trajectory groups were associated with a higher rate of IHCA: low and fluctuating SBP, high and fluctuating HR, persistent hypothermia, initially resolving but recurring tachypnea, and low and fluctuating oxygen saturation. Except for the persistent hypothermia group, the other four trajectory groups were more likely to have fever and higher levels of lactic acid, C-reactive protein, and D-dimer. Within each vital sign, the IHCA-prone trajectory group was associated with a higher triage level and a higher mortality rate, compared to other trajectory groups. We identified five novel subphenotypes associated with a higher likelihood of IHCA, with some distinct patterns in clinical course and laboratory test results. A better understanding of the pre-IHCA vital sign trajectories may potentially reverse clinical deterioration and reduce IHCA in the ED.