The impact of qualitative respiratory cultures on mortality in critically ill patients with hospital-acquired pneumonia

This retrospective cohort study evaluated differences in all-cause mortality associated with quantitative versus qualitative cultures in critically ill patients with suspected hospital-acquired pneumonia (HAP). Patients were included if lower respiratory tract (LRT) cultures were obtained and were stratified by culture strategy: invasive (bronchial alveolar lavage [BAL] or nonbronchoscopic BAL) or noninvasive (endotracheal tube aspirate or sputum culture). Mortality data and secondary endpoints were compared between groups. A total of 113 patients met inclusion criteria (invasive = 72, noninvasive = 41). No significant difference in all-cause mortality was detected between the groups (37.5% and 31.7%, respectively; P = 0.54). Secondary endpoints were similar; however, patients in the invasive group had greater mean total antibiotic days of therapy compared to the noninvasive group (21.2 ± 13.5 days vs 15.5 ± 8.3 days, P = 0.01). The present study suggests that using invasive methods to obtain LRT cultures in critically ill patients with suspected HAP did not offer a detectable benefit in mortality or clinical outcomes when compared to noninvasive diagnostic methods.