THE VALUE OF CLINICAL JUDGMENT IN THE DIAGNOSIS OF NOSOCOMIAL PNEUMONIA

BACKGROUND: Nosocomial pneumonia presents a diagnostic and therapeutic challenge in the care of critically ill patients. The present study w as designed to determine as closely as possible the occurrence of noso comial pneumonia in surgical intensive care unit (ICU) patients using clinical, radiographic, and bacteriological parameters in a prospectiv e concurrent fashion. METHODS: This clinical study enrolled all surgic al, trauma, and neurosurgical patients admitted to a surgical IOU over a 13-month period. Routine surveillance was used to identify those pa tients suspected of developing nosocomial pneumonia. Numerous clinical parameters concerning ventilatory support, acute lung injury, organ d ysfunction, nutrition, and length of stays were used to identify facto rs disposing to development of pneumonia. Univariate and multivariate analyses were used for this purpose. Patients thought to have pneumoni a were then followed concurrently to determine, as closely as possible , whether pneumonia was present by serial examination of clinical, bac teriologic, and radiographic data. Those ''validated'' by this process were then compared to those ''nonvalidated'' to see if any distinctio n could be made. RESULTS: Of the 352 patients enrolled, 46 (13%) were initially labeled as having developed nosocomial pneumonia when compar ed to the 306 patients without pneumonia. Univariate analysis demonstr ated a greater need for intubation and mechanical ventilation, longer mechanical ventilation, more acute lung injury, longer ICU and hospita l stays, poorer nutrition, and higher mortality (17% versus 5%, P < 0. 01). Multivariate analysis demonstrated only length of IOU stay and le ngth of intubation/mechanical ventilation as longer in the pneumonia g roup. On further concurrent review, 23 of 46 patients were validated a s having pneumonia while the rest were felt not to have pneumonia. Whe n the two groups were compared, only asymmetric and segmental radiogra phic infiltrates distinguished validated from nonvalidated pneumonia p atients and all other clinical parameters, including mortality and len gth of stay, were similar. CONCLUSION: Nosocomial pneumonia was initia lly suspected in 13% of this ICU population. Numerous clinical paramet ers clearly distinguished these pneumonia patients from others and the y suffered a substantially higher mortality. However, within this pneu monia group, only half of the patients could be validated as truly hav ing pneumonia using available clinical parameters. Nevertheless, those validated were indistinguishable in their clinical behavior from thos e who were not. This calls into question the need for elaborate and so metimes expensive investigations for diagnosis of nosocomial pneumonia .