THE ROLE OF INTRAGASTRIC ACIDITY AND STRESS ULCUS PROPHYLAXIS ON COLONIZATION AND INFECTION IN MECHANICALLY VENTILATED ICU PATIENTS - A STRATIFIED, RANDOMIZED, DOUBLE-BLIND-STUDY OF SUCRALFATE VERSUS ANTACIDS

This study evaluates the effects of sucralfate and antacids on intraga stric acidity, colonization of stomach, oropharynx and trachea, and th e incidence of ventilator-associated pneumonia (VAP) in mechanically v entilated patients in intensive care units. We conducted a prospective randomized double-blind trial in which patients were stratified on in itial gastric pH. Intragastric acidity was measured with computerized, continuous intragastric monitoring. The diagnosis of VAP was establis hed with protected specimen brush and/or bronchoalveolar lavage. The s tudy included consecutive eligible patients with mechanical ventilatio n and nasogastric tube. Interventions: After stratification on initial intragastric pH into two groups, patients from both groups were rando mly assigned to receive either antacids (a suspension of aluminum hydr oxide and magnesium hydroxide), 30 mt every 4 h, or sucralfate, 1 g ev ery 4 h. Continuous intragastric pH monitoring was performed in 112 pa tients (58 antacids, 54 sucralfate). Using predetermined criteria, col onization of stomach, oropharynx, and trachea, and the incidence of VA P were assessed. Altogether, 141 patients were included (74 receiving antacids, 67 sucralfate) and continuous intragastric pH monitoring was performed in 112 patients, with a mean of 75 h per patient. The media n pH and the percentage of time with a pH < 4.0 were calculated from e ach measurement. No significant differences in median pH values (4.7 /- 2.2 and 4.5 +/- 2.0 for antacids and sucralfate, respectively) were observed. Median pH values were higher in patients with gastric bacte rial colonization than in noncolonized patients (5.5 rt 2.1 and 3.3 +/ - 2.0, p < 0.01), but colonization of oropharynx and trachea was not r elated to intragastric acidity. Thirty-one patients (22%) developed VA P, with a similar incidence in both treatment groups. In addition, ant ibiotic use, duration of hospitalization, and mortality rates were sim ilar in both groups. Enteral feeding did not change intragastric acidi ty significantly but increased gastric colonization with Enterobacteri aceae, without influencing oropharyngeal and tracheal colonization. An tacids and sucralfate had a similar effect on intragastric acidity, co lonization rates, and incidence of VAP. Intragastric acidity influence d gastric colonization but not colonization of the upper respiratory t ract or the incidence of VAP. Therefore, it is unlikely that the gastr opulmonary route is important for the development of VAP.