VALUE OF C-REACTIVE PROTEIN IN THE DETECTION OF BACTERIAL-CONTAMINATION AT THE TIME OF PRESENTATION IN DRUG-INDUCED ASPIRATION PNEUMONIA

Study objectives: To compare the plasma concentration of C-reactive pr otein (CRP) with traditional markers for diagnosis of bacterial pneumo nia in patients with suspected aspiration. Design: Prospective, nonran domized, controlled study of consecutive hospital admissions. Setting: Toxicology ICU in a university hospital. Patients or participants: Ac utely poisoned comatose patients admitted to the hospital with suspici on of aspiration pneumonia. Interventions: Distal protected catheter s ampling per fiberoptic bronchoscopy and bacteriologic culture were emp loyed as a standard to detect the bacterial component of suspected asp iration pneumonia. Plasma CRP concentrations, temperature, and WBC cou nt were measured on hospital day 1. Measurements and results: Sixty-si x patients were evaluated. Thirty-two had bacterial contamination by p ositive culture (greater than or equal to 10(3) cfu/mL). Multiple rece iver-operating characteristic (ROC) curves were used to compare each p arameter for detection of infection secondary to aspiration. The ROC c urve of CRP concentrations showed that a CRP > 75 mg/L is associated w ith bacterial contamination with a sensitivity of 87%, specificity of 76%, positive predictive value of 78%, and negative predictive value o f 87%. ROC curves of temperature and WBC count demonstrated poor diagn ostic value of these markers in indicating the bacterial component of suspected aspiration pneumonia. Conclusions: Early measurement of CRP is useful for the diagnosis of aerobic bacterial content of aspiration pneumonia and perhaps in determining the need for invasive bacteriolo gic sampling. Temperature and WBC count are poor indicators of bacteri al infection of aspiration pneumonia in poisoned patients.