Base deficit is superior to pH in evaluating clearance of acidosis after traumatic shock

This study was done to evaluate the differences in base deficit (BD) clearance, pH normalization, and the occurrence of complications between survivors and nonsurvivors after trauma.

Concurrent data entry with retrospective review.

Trauma patients meeting registry criteria from July 1990 through August 1995 with arterial blood gases performed within 1 hour of admission and admission BD < or = -6 were included. Data was grouped by BD category (moderate, -6 to -9; severe, < or = -10). Group means +/- SEM were compared with a two-tailed t test.

Six hundred seventy-four patients met entry criteria. Survivors in both the moderate and severe BD groups had improved their BD within 4 hours and normalized their BD by 16 hours. Nonsurvivors did not improve their BD category until 8 hours (for the severe group) and 16 hours (for the moderate group) and did not normalize BD before 24 hours. The BD differences between survivors and nonsurvivors were significant at each time interval, whereas pH differences were significant at 2 hours in the moderate group and at 2, 16, and 24 hours in the severe group. Patients who failed to improve their BD > -6 had an increased frequency of adult respiratory distress syndrome, multiple organ failure, and mortality.

Base deficit reveals differences in metabolic acidosis between survivors and nonsurvivors not shown by pH determinations and is clearly a better marker of acidosis clearance after shock.