Systolic blood pressure below 110 mmHg is associated with increased mortality in blunt major trauma patients: Multicentre cohort study

Abstract

IntroductionNon-invasive systolic blood pressure (SBP) measurement is often used in triaging trauma patients. Traditionally, SBP<90mmHg has represented the threshold for hypotension, but recent studies have suggested redefining hypotension as SBP<110mmHg. This study aims to examine the association of SBP with mortality in blunt trauma patients. MethodsThis 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. Results47,927 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 135mmHg (IQR=120–152). We identified SBP<110mmHg as a cut off for hypotension, where a significant increase in mortality was observed. Mortality rates doubled at <100mmHg, tripled at <90mmHg and were 5- to 6-fold at <70mmHg, irrespective of age. ConclusionWe recommend triaging adult blunt trauma patients with a SBP<110mmHg to resuscitation areas within dedicated trauma units for close monitoring and appropriate management.