Early Sex Differences in pH, Base Excess and Lactate for the Prediction of Mortality in Trauma Patients

In trauma patients, early correction of acid-base imbalances is crucial for survival, but time-dependent and sex-specific predictive data are limited. The aim was to analyze the time-dependent, early sex differences in pH, base excess (BE) and lactate regarding mortality in trauma patients.

Internal data of trauma patients served for retrospective analysis. pH, BE and lactate values were measured until 48 h after admission. Patients were compared according to sex and survivor status. pH < 7.25, BE < -5.5 mmol/L and lactate > 4 mmol/L were tested as time-dependent predictors for mortality, adjusted for age and Injury Severity Score (ISS). The respective area under the curve (AUC) was calculated and compared by sex. Level of significance was set at p < 0.05.

In the total cohort of 3653 patients (mean age: 45.8 ± 20.2 years, 73.4% male), mortality rates were comparable between females (26.7%) and males (26.9%; p = 0.931) at a similar ISS (median 25, respectively; p = 0.821). Female non-survivors had a higher rate and grade of pelvic injuries than male non-survivors (p = 0.005). At admission, males had more extreme values in pH (7.31 ± 0.13 vs. 7.32 ± 0.14; p < 0.001) and lactate (3.03 ± 2.53 vs. 2.71 ± 2.53; p < 0.001). pH and BE differed early by survivor status (within 4 h). Lactate was always higher in non-survivors. A pH < 7.25 was predictive in males at most time points (except for 0/4/8/48 h), but for females only at 12 h. BE < -5.5 mmol/L was predictive for males at 6 h and 12-48 h, and for females at 8-48 h. Lactate > 4 mmol/L was prognostic at 0-1 h and 6-48 h in males but in females at 0/12/24 h.

Trauma patients display early differences in injury pattern and acid-base parameters according to survivor status and sex. Time- and sex-dependent referencing could aid in early risk estimation and the subsequent extent of surgical treatment.