A Retrospective Study of Nosocomial Pneumonia in Postoperative Patients Shows a Higher Mortality Rate in Patients Receiving Nasogastric Tube Feeding

Abstract

Pneumonia remains a significant cause of morbidity and mortality in surgical patients. Though most studies have focused on pneumonia in trauma or special respiratory intensive care units (ICU), we examine postoperative ventilator-associated pneumonia in patients undergoing elective operations. We hypothesized that a study of multiple clinical variables would disclose factors influencing morbidity and mortality in these patients. We conducted a retrospective review of 1969 patients who underwent elective general, cardiac, and general thoracic procedures during a 6-month period in a private teaching hospital. A total of 77 patients (3.9%) developed postoperative ventilator-associated pneumonia. Thirty-eight (49%) patients had a history of smoking and 27 (35%) had chronic obstructive pulmonary disease (COPD). Among these 77 patients, 20 (26%) experienced recurrent pneumonia. The overall mortality rate for patients developing pneumonia was 34 per cent. At diagnosis of pneumonia, 33 patients were receiving enteral nutrition through nasogastric feeding tubes, whereas 41 received no enteral feeding. The method of nutritional intake was not known in 3 patients. The feeding/nonfeeding groups were similar in age and underlying disease, differing significantly only in the higher number of smokers in the patients not receiving enteral nutrition ( P = 0.03). To our surprise, the mortality rate from all causes was higher ( P = 0.018) in the patients who received tube feedings through soft, nasogastric feedings (33%) than in those not enterally fed (17%). Parenteral nutrition, COPD, number of ventilator days, and the location of the tip of the feeding tube did not correlate with mortality. The mortality rate from all causes was higher in patients with postoperative pneumonia who received tube feedings, despite similar underlying medical illnesses. Enteral feeding of postoperative surgical patients has many desirable effects, but prospective studies should address harmful effects, such as presumed aspiration and related pneumonia.