Evaluation of white blood cell count, neutrophil percentage, and elevated temperature as predictors of bloodstream infection in burn patients

Objective: To investigate whether specific values of or changes in temperature, white blood cell count, or neutrophil percentage were predictive of bloodstream infection in burn patients. Design: Retrospective review of electronic records. Setting: Intensive care center at the US Army Institute of Surgical Research Burn Center. Patients: Burn patients with blood cultures obtained from 2001 to 2004. Main Outcome Measures: Temperature recorded at the time blood cultures were obtained; highest temperature in each 6-hour interval during the 24 hours prior to this; white blood cell count and neutrophil percentage at the time of obtaining the blood culture and during the 24 hours preceding the blood culture; demographic data; and total body surface area burned. Results: A total of 1063 blood cultures were obtained from 223 patients. Seventy-three people had 140 blood cultures from which microorganisms were recovered. Organisms that were recovered from blood cultures included 80 that were gram negative, 54 that were gram positive, 3 that were mixed gram positive/gram negative, and 3 yeasts. Although white blood cell count and neutrophil percentage at the time of the culture were statistically different between patients with and patients without bloodstream infection, receiver operating characteristic curve analysis revealed these values to be poor discriminators (receiver operating characteristic curve area=0.624). Temperature or alterations in temperature in the preceding 24-hour period did not predict presence, absence, or type of bloodstream infection. Conclusions: Temperature, white blood cell count, neutrophil percentage, or changes in these values were not clinically reliable in predicting bloodstream infection. Further work is needed to identify alternative clinical parameters, which should prompt blood culture evaluations in this population.