Systolic blood pressure below 110 mm Hg is associated with increased mortality in blunt major trauma patients: multicentre cohort study

Abstract

Introduction: Non-invasive systolic blood pressure (SBP) measurement is often used in triaging trauma patients. Traditionally, SBP< 90 mm Hg has represented the threshold for hypotension, but recent studies have suggested redefining hypotension as SBP < 110 mm Hg. This study aims to examine the association of SBP with mortality in blunt trauma patients.

Methods: This is an analysis of prospectively recorded data from adult (≥ 16 years) blunt trauma patients. Included patients presented to hospitals belonging to the Trauma Audit and Research Network (TARN) between 2000 and 2009. The primary outcome was the association of SBP and mortality rates at 30 days. Multivariate logistic regression models were used to adjust for the influence of age, gender, Injury Severity Score (ISS) and Glasgow Coma Score (GCS) on mortality.

Results: 47,927 eligible patients presented to TARN hospitals during the study period. Sample demographics were: median age: 51.1 years (IQR=32.8-67.4); male 60% (n=28,694); median ISS 9 (IQR=8-10); median GCS 15 (IQR=15-15); and median SBP 135 mm Hg (IQR=120-152). We identified SBP< 110 mm Hg as a cut off for hypotension, where a significant increase in mortality was observed. Mortality rates doubled at < 100 mm Hg, tripled at < 90 mm Hg and were 5- to 6-fold at < 70 mm Hg, irrespective of age.

Conclusion: We recommend triaging adult blunt trauma patients with a SBP< 110 mm Hg to resuscitation areas within dedicated trauma units for close monitoring and appropriate management.