Vital Sign Patterns Before Shock-Related Cardiopulmonary Arrest


Jessie S. Davis a, Jared A. Johns b, David J. Olvera, Allen C. Wolfe, Alin Gragossian d, Eliana M. Rees e, Edward A. Pillar b, Daniel P. Davis b,c,f

a Desert Regional Medical Center, Department of Emergency Medicine, Palm Springs, CA, United States

b Arrowhead Regional Medical Center, Department of Emergency Medicine, Colton, CA, United States

c Air Methods Corporation, Greenwood Village, Colorado, United States

d Drexel University, Department of Emergency Medicine, Philadelphia, PA, United States

e University of California at San Diego, San Diego, CA, United States

f California University of Science and Medicine, San Bernardino, CA, United States


Objective: Traditional vital sign thresholds reflect an increased risk of mortality, which may occur hours, days, or weeks following illness/injury, limiting immediate clinical significance to guide rescue therapy to avoid arrest. Our objective is to explore vital sign patterns prior to arrest due to shock.

Design: This retrospective observational analysis utilized physiological data from adult helicopter patients suffering provider-witnessed arrest. Pre-arrest values for systolic blood pressure (SBP), mean arterial pressure (MAP), heart rate (HR), shock index, and end-tidal carbon dioxide (EtCO2) were modeled against time using polynomial linear regression. The “terminal inflection point” beyond which arrest was imminent was identified where slope equals 1.0 (shock index) or -1.0 (SBP, MAP, HR, EtCO2) and was then compared to initial values.

Setting: Air ambulance services.

Patients: 70 helicopter patients over age fourteen suffering cardiac arrest.

Results: SBP and MAP demonstrated a gentle decline followed by acceleration beyond the inflection point (SBP 80.7 mmHg, MAP 61.9 mmHg). HR demonstrated an increase followed by a terminal drop, but inflection point values fell within normal range. Shock index increased gradually from a mean of 0.9 to the inflection point of 1.1. Initial EtCO2 values declined gradually from normal (34.4 mmHg) to the inflection point (24.7 mmHg), then dropped precipitously into arrest. All inflection points occurred 2–5 min prior to arrest.

Conclusions: Vital sign patterns were defined for SBP, MAP, HR, shock index, and EtCO2 with clear inflection points identified 2–5 min prior to arrest. These patterns may help guide therapy to reverse deterioration and prevent arrest.

Keywords: Shock, End-tidal CO2, Cardiopulmonary arrest, Pre-arrest patterns, Vital sign patterns, Capnography

Click below to read the full clinical paper published by Resuscitation, Volume 139, P337-342, June 01, 2019