INCREMENTAL-ANALYSIS OF DIAGNOSTIC PERITONEAL-LAVAGE FLUID IN ADULT ABDOMINAL-TRAUMA

It is uncertain how much diagnostic peritoneal ravage (DPL) fluid must be recovered from abdominal trauma patients to avoid falsely low red blood cell (RBC) counts, A study was carried out to investigate this c ontroversy. A convenience sample of adult abdominal trauma patients in a Level 1 university trauma center who were undergoing DPL with 1 L c rystalloid was enrolled. Subjects with grossly positive or colorless e ffluent were excluded. A blinded prospective experimental design was u sed. Differ Differences were evaluated among RBC counts collected at 2 00, 400, 600, and 800 mt of returned fluid using repeated measures ana lysis of variance. In 11 patients, mean RBC counts collected at 200 an d 400 mL were 24,600 (95% confidence interval [CI], 20,700 to 29,100) and 39,700 (95% CI, 33,200 to 47,100) cells/mu L. These were substanti ally lower than the final mean count of 95,800 (95% CI, 80,000 to 115, 800), measured at 800 mL (F = 23.7, P < .0001). Mean counts at 600 mt were less than those obtained at 800 mL but were not statistically dif ferent (P = .08). Two of the 11 subjects would have been misclassified (as not requiring surgery) had ''early'' sampling been used. In abdom inal trauma patients, the RBC count of DPL fluid regularly increases a s more fluid is recovered. It is important to collect >600 mt of efflu ent to avoid misleading, low RBC counts and misclassification of patie nts. Copyright (C) 1997 by W.B. Saunders Company.