Background Acute haemorrhage is a major contributor to trauma related morbidity and mortality. Quantifying blood loss acutely and accurately is a difficult task and no currently accepted standard exists. We introduce a simple shock grading tool incorporating vital signs, fluid response and estimated blood loss to describe shock grade during the primary survey based on the original Advanced Trauma Life Support (ATLS) classification.

Methods We performed a prospective cohort study of all trauma patients admitted to our emergency room over a 1-year period to evaluate the utility of this tool for emergency physicians to detect significant haemorrhage in the trauma patient. Shock grades were prospectively assigned to patients by the trauma team as part of the primary survey, and followed up to assess for outcomes. The primary outcome was a composite endpoint of clinical, radiological and operative findings consistent with significant haemorrhage. Data were analysed using linear and logistic regression to assess predictive ability and receiver operator characteristic curve to assess overall diagnostic accuracy.

Results The overall sensitivity of the shock grading tool was 83%. The diagnostic accuracy based on area under receiver operator characteristic curve was 0.86. There was also a significant association between increasing shock grade and both injury severity score (β coefficient 7.0, p<0.001, 95% CI 6.2 to 7.8) and the presence of significant haemorrhage (OR 5.1, p<0.001, 95% CI 3.6 to 7.3).

Conclusions We conclude that a simple ATLS based clinical tool that objectively categorises haemorrhagic shock is a useful part of the primary survey of the trauma patient, although a larger study with higher statistical power is required to evaluate this conclusion further.