Predicting increased fluid requirements during the resuscitation of thermally injured patients

Background: We determined whether factors present soon after burn predict which patients will receive more than 4 mL/kg/% burn during the first 24 hours, and whether total fluid intake during the first 24 hours (VOL) contributes to in-hospital mortality (MORT). Methods: We reviewed the records of patients admitted during 1987-97. The modified Brooke resuscitation formula was used. One hundred four patients met inclusion criteria: total body surface area burned (TBSA) greater than or equal to 20%; admission directly from the field; weight > 30 kg; no electric injury, mechanical trauma, or blood transfusions; and survival > 24 hours postburn. Eighty-nine records were complete. Results: Mean TBSA was 43%, mean full-thickness burn size was 21%, mean age was 41 years, mean VOL was 4.9 mL/ kg/% burn, and mean lactated Ringer's volume was 4.4 mL/kg/% burn; 53% had inhalation injury. MORT was 25.8%. Mean urine (output was 0.77 mL/kg/h). By linear regression, VOL was associated with weight (negatively) and full-thickness burn size (r(2) = 0.151). By logistic regression, receipt of over 4 mL/kg/% burn was predicted at admission by weight (negatively) and TBSA; by 24 hours postburn, mechanical ventilation replaced TBSA. With respect to MORT, logistic regression of admission factors yielded a model incorporating TBSA and an age function; by 24 hours postburn, the worst base deficit was added. Conclusion: Burn size and weight (negatively) were associated with greater VOL. However, a close linear relationship between burn size and VOL was not observed. Mechanical ventilation supplanted TBSA by 24 hours as a predictor of high VOL. Worst base deficit, TBSA, and an age function, but not VOL, were predictors of MORT.