A Comparison of the Shock Index and Conventional Vital Signs to Identify Acute, Critical Illness in the Emergency Department,☆☆,

https://doi.org/10.1016/S0196-0644(94)70279-9Get rights and content

Abstract

See related editorial, The Shock Index: All that Glitters..."

Study objective: Shock index (SI) (heart rate/systolic blood pressure; normal range, 0.5 to 0.7) and conventional vital signs were compared to identify acute critical illness in the emergency department. Design: Quasi-prospective study. Patients: Two hundred seventy-five consecutive adults who presented for urgent medical care. Interventions: Patients had vital signs, SI, and triage priority recorded on arrival in the ED and then their final disposition. Results: Two groups were identified retrospectively by the SI; group 1 (41) had an SI of more than 0.9, and group 2 (234) had an SI of less than 0.9 on arrival in the ED. Although both groups had apparently stable vital signs on arrival, group 1 had a significantly higher proportion of patients who were triaged to a priority requiring immediate treatment (23 versus 45; P<.01) and required admission to the hospital (35 versus 105; P<.01) and continued therapy in an ICU (10 versus 13; P<.01). Conclusion: With apparently stable vital signs, an abnormal elevation of the SI to more than 0.9 was associated with an illness that was treated immediately, admission to the hospital, and intensive therapy on admission. The SI may be useful to evaluate acute critical illness in the ED. [Rady MY, Smithline HA, Blake H, Nowak R: A comparison of the shock index and conventional vital signs to identify acute, critical illness in the emergency department. Ann Emerg Med October 1994;24:685-690.]

Section snippets

INTRODUCTION

Conventional vital signs (eg, heart rate [HR], systolic blood pressure [SBP], and diastolic blood pressure [DBP]), are commonly measured to evaluate hemodynamic stability of critically ill patients in the emergency department. However, several studies have established that the normal values of such measurements may conceal significant deficiency in systemic oxygenation and cardiac function and an increased likelihood of death.1, 2, 3 The shock index (SI) is a ratio calculated to weigh HR and

MATERIALS AND METHODS

This quasi-prospective study was approved by the Institutional Review Board for Human Research of Henry Ford Hospital. The purpose was to identify if either conventional vital signs (HR, SBP, and DBP) or SI measured on arrival to the ED could identify acute, critical illness requiring immediate treatment and admission to the ICU. A consecutive sample of 275 patients who presented to the ED for urgent medical care served as the study population. Exclusion criteria were age less than 18 years,

RESULTS

Our study included a total of 275 patients, of whom 145 were men. Mean age was 52±20 years. The mean SI was 0. 7±0.3 and ranged from 0.3 to 3.0 (normal range, 0.5 to 0.7).4 Patients were divided into two groups (1 and 2) using an SI of 0.9 as a cutoff value because an SI of more than 0.9 was found to be clinically significant and frequently associated with deficient global oxygenation and ischemia after resuscitation and hemodynamic stabilization.6, 7

The nature of acute illness in these

DISCUSSION

Conventional vital signs (HR, SBP, and DBP) are measured commonly to evaluate cardiovascular and hemodynamic stability in the ED, although apparent normality of these measurements can mask significant global ischemia and cardiac dysfunction in critically ill patients.8, 9, 10 Allgower et al were the first to use the SI to evaluate patients presenting with gastrointestinal hemorrhage.11 They found that an elevation of the SI was an earlier and better indicator than HR, SBP, or DBP measured

CONCLUSION

The stability of conventional vital signs (HR, SBP, and DBP) considered individually failed to identify critically ill patients in the ED. An elevation of the SI to more than 0.9 and stable vital signs implied a critical illness that required immediate treatment, admission to the hospital, and continued intensive monitoring and therapy in the ICU. The SI is a ratio calculated to weigh HR and SBP differently and may be better than HR, SBP, and DBP measured individually to identify critically ill

References (15)

There are more references available in the full text version of this article.

Cited by (0)

From the Department of Emergency Medicine, Henry Ford Hospital, Detroit, Michigan.

☆☆

Address for reprints: Mohamed Rady, MD, PhD, Department of Emergency Medicine, Henry Ford Hospital, 2799 West Grand Blvd, Detroit, Michigan 48202

Reprint no. 47/1/59539

View full text