The effect of acidified enteral feeds on gastric colonization in critically ill patients: Results of a multicenter randomized trial

Objective: To evaluate the effect of acidified enteral feeds on gastric colonization in critically ill patients compared with a standard feeding formula, Design: Randomized, double-blind, multicenter trial. Setting: Eight mixed intensive care units at tertiary care hospitals Patients: We recruited mechanically ventilated critically ill patients expected to remain ventilated for >48 hrs, We excluded patients with gastrointestinal bleeding, acidemia, and renal failure requiring dialysis, We enrolled 120 patients; 38% were female, age (mean +/- so) was 57.6 +/- 19.3 yrs, and Acute Physiology and Chronic Health Evaluation II score (mean +/- so) was 21.6 +/- 7.6, Interventions: Vital High Nitrogen (Abbott Laboratories, Ross Products Division, Columbus, OH) was used as the standard feeding formula for the control group (pH = 6.5), Hydrochloric acid was added to Vital Nigh Nitrogen to achieve a pH of 3.5 in the experimental group. Measurements and Main Results: The main outcome measure was gastric colonization. Secondary outcomes included gastric pH, pneumonia, and mortality. The mean gastric pH in patients receiving acid feeds was lower (pH = 3.3) compared with controls (pH = 4.6; p < .05). One patient (2%) on acid feeds was colonized in the stomach with pathogenic bacteria, compared with 20 patients (43%) in the control group (p < .001), There was no difference in the incidence of pneumonia (6.1% in the acid feeds group vs. 15% in the control group; p = .19), Overall, there were 15 deaths in the acid feeds group and seven in the control group (p = .10); four patients in the acid feeds group and three in the control group died during the study period (p not significant), Conclusions: Acidified enteral feeds preserve gastric acidity and substantially reduce gastric colonization in critically ill patients. Larger studies are needed to examine its effect on ventilator-associated pneumonia and mortality.