CLINICAL QUESTION: Can shock index (SI) in the ED predict the likelihood for hospital admission and inpatient mortality?
BACKGROUND: SI is defined as heart rate divided by systolic blood pressure. It is postulated to have an inverse relationship to cardiac output. SI has been studied as a prognostic metric of poor outcomes in patients with myocardial infarction, gastrointestinal hemorrhage, sepsis, and trauma. There are no large studies on SI in the general ED population.
STUDY DESIGN: Retrospective chart review.
SETTING: Academic tertiary care center.
SYNOPSIS: All ED patients over 18 years of age over a 12-month period were included in the study for a total of 58,633 charts. Charts were excluded if the patient presented in cardiac arrest, left prior to full evaluation in the ED, or had an incomplete or absent first set of vital signs. Likelihood ratio (LR) values of greater than 5 and 10 were considered moderate and large increases in the outcomes, respectively. Authors found SI greater than 1.2 had a positive LR of 11.69 for admission to the hospital and a positive LR of 5.82 for inpatient mortality.
This study identified potential thresholds for SI but did not validate them. Whether SI would be a useful tool for triage remains unanswered.
BOTTOM LINE: Initial SI greater than 1.2 at presentation to the ED was associated with increased likelihood of hospital admission and inpatient mortality.
CITATIONS: Balhara KS, Hsieh YH, Hamade B, et al. Clinical metrics in emergency medicine: the shock index and the probability of hospital admission and inpatient mortality. Emerg Med J. 2017 Feb;34(2):89-94.
Dr. Dietsche is a clinical instructor, Division of Hospital Medicine, University of Colorado School of Medicine, Aurora.