Trends in nosocomial pneumonia in surgical patients as we approach the 21st century: A prospective analysis

To compare outcome and prognostic factors of pneumonia in surgical patients, we prospectively studied all episodes of nosocomial infection at all sites in 1997 on the surgical services at a single hospital. Pneumonia accounted for 74 of 287 episodes of infection. The crude mortality for pneumonia was 31.1 versus 12.2 per cent for all other infections (P < 0.001). Pneumonia patients had a higher severity of illness compared with those with infections at other sites (18.7 ± 0.8 vs 14.0 ± 0.5; P < 0.001). Crude mortality remained higher in pneumonia patients when compared with an infected control group matched for severity of illness and age (31% vs 15%; P = 0.02). Staphylococcus aureus (15%) was the most common isolate, followed by Pseudomonas aeruginosa (9%). Resistant Gram-positive cocci accounted for 7 per cent of all isolates but was associated with a 60 per cent mortality vs 28 per cent with other organisms (not significant; P = 0.1). The Acute Physiology and Chronic Health Evaluation (APACHE) II score for patients with resistant Gram-positive cocci was 22 ± 1 versus 18 ± 1 with other organisms (P = 0.03). Nonsurvivors of pneumonia were older (58 ± 2 vs 51 ± 3; P = 0.03), had a higher APACHE II score (23 ± 1 vs 17 ± 1; P < 0.001), and were diagnosed later in their hospital course (18 ± 4 days vs 11 ± 1; P = 0.05) compared with survivors. Pneumonia-associated mortality in surgical patients remains high compared with other infections even when correcting for differences in severity of illness. Although resistant Gram-positive cocci appear to be increasing in frequency, they may represent markers of severe illness rather than true pathogens. Increasing age, severity of illness, and length of stay before diagnosis were all associated with a worse prognosis.