POSTOPERATIVE PNEUMONIA - A PROSPECTIVE-STUDY OF RISK-FACTORS AND MORBIDITY

Background. Postoperative pneumonia (PP) is a major complication that has been linked to microaspiration of pathogens originating in the gas trointestinol tract. This prospective study was performed to define th e role of gastric bacterial aspiration in the development of PP. Metho ds. Informed consent was obtained before operations from 140 veterans scheduled for major elective procedures requiring nasogastric lubes, a nd cultures were obtained of the gastric contents and sputum twice dai ly after operation.Results. PP developed in 26 (18.6%) of 140 patients . The patients who had PP did not differ from those with no pneumonia after operation except for a history of chronic obstructive pulmonary disease, which was found in 38.5% of those with PP compared with 20% o f patients with no pneumonia (p < 0.05). Morbidity was increased in as sociation with PP, because length of stay in the surgical intensive ca re unit (6.2 vs 2.6 days), days intubated (2.7 vs 0.6), total postoper ative days (15.3 vs 8.4), and mortality rates (19.2% vs 1.7%) were gre ater than in patients with no pneumonia. Gastric pathogens were presen t on entry in 38% of patients, and 32% of these had PP compared with 1 3% whose initial gastric cultures were sterile (p = 0.01). Colonizatio n sputum for greater than 24 hours with gastric pathogens occurred in 28% of patients. These patients had a 40% incidence of PP compared wit h 12% in patients without such evidence of microaspiration (p < 0.01). Conclusions. PP is a morbid postoperative complication associated wit h not only chronic obstructive pulmonary disease but also the presence of gastric bacteria during operation and transmission of gastric bact eria to the pulmonary tree after operation.