Base deficit stratifies mortality and determines therapy

Abstract

Objective: To determine the association of base deficit with mortality and other factors affecting mortality.

Design: Retrospective review.

Setting: Tertiary care center.

Participants: Consecutive samples of 3791 trauma patients admitted with an arterial blood gas sample taken in the first 24 hours.

Main outcome measures: Age, injury mechanism, head injury, shock (systolic blood pressure less than 90 mm Hg), Revised Trauma Score, TRISS probability of survival Ps, and mortality.

Results: Most (3038) patients (80.1%) exhibited a base deficit. Base deficit, age, injury mechanism, and head injury were associated with mortality using logistic regression. Age less than 55 years, no head injury, and a base deficit of -15 mmol/L were associated with 25% mortality. Age greater than or equal to 55 years with no head injury or age less than 55 years with a head injury and a base deficit of -8 mmol/L were associated with a 25% mortality. When shock was added to the model, all factors remained significant, and base deficit was supplemental to blood pressure. Base deficit also added significantly to the Revised Trauma Score and TRISS measurements.

Conclusions: The base deficit is an expedient and sensitive measure of both the degree and the duration of inadequate perfusion. It is useful as a clinical tool and enhances the predictive ability of both the Revised Trauma Score and TRISS.