Role of selective digestive decontamination (SDD) in the prevention of nosocomial pneumonia (NP): is gastric decontamination necessary?

In the course of a prospective selective digestive decontamination (SDD) trial to prevent nosocomial pneumonia (NP) during mechanical ventilation (MV), we carried out serial cultures of gastric aspirate to assess the importance of gastric colonization for potential respiratory pathogens and its relationship to the simultaneous gastric pH, to whether the patients were receiving Sucralfate or Ranitidine and to the nutritional biochemical parameters. If NP developed, a bronchial sample was taken by fibreoptic bronchoscopy to determine the causal organisms and its relationship to the previous gastric isolated. Results show: 1) Increase in aerobic Gram negative bacilli colonization during hospitalization. 2) Direct relationship between colonization level and gastric pH. 3) Greater pH in ranitidine vs sucralfate group. 4) Low incidence of NP (11%), the majority of these (66%) being early. 5) No bacteriological correlation between gastric colonization and aetiological agents of NP. 6) Close relationship between pharyngeal colonization and causative germs of pulmonary infection (40%).