Objective: To assess selective digestive decontamination for preventing nosocomial pneumonia and mortality in mechanically ventilated patients.
Design: Prospective, randomized, placebo-controlled, double-blind study.
Setting: Respiratory intensive care unit of a 1000-bed teaching hospital.
Patients: 80 patients receiving mechanical ventilation for more than 72 hours.
Interventions: Patients received selective digestive decontamination using polymyxin E, tobramycin, and amphotericin B through a nasogastric tube and also topically in the oropharynx; control patients received placebo. All patients received intravenous cefotaxime for 4 days or other systemic antibiotics if required.
Measurements: Bacteriologic surveillance (three times a week) was done by quantitatively culturing tracheal aspirates, pharyngeal swabs, and gastric juice. The diagnosis of pneumonia was based on quantitative cultures of protected specimen brush samples (≥ 103 CFU/mL [colony forming units/mL]) or bronchoalveolar lavage fluid (≥ 104 CFU/mL) and autopsy findings.
Results: Bronchial, oropharyngeal, and gastric colonization by gram-negative bacilli and Candida species was lower in the selective digestive decontamination group compared with the placebo group. Nonsignificant differences were found in the incidence of nosocomial infections (28% compared with 37%; odds ratio, 0.66; 95% CI, 0.35 to 1.25) and nosocomial pneumonia (18% compared with 24%; odds ratio, 0.7; CI, 0.33 to 1.46) and in the crude mortality rate (31% compared with 27%; odds ratio, 1.21; CI, 0.63 to 2.34) when comparing digestive decontamination with placebo, respectively.
Conclusions: Selective digestive decontamination in our mechanically ventilated patients significantly decreased the colonization rate of gram-negative bacilli and of Candida species but not of Staphylococcus aureus. It did not decrease the incidence of nosocomial pneumonia, mortality, length of stay, or the duration of mechanical ventilation.