The effect of acidified enteral feeds on gastric colonization in critically ill patients: results of a multicenter randomized trial. Canadian Critical Care Trials Group.

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 +/- SD) was 57.6+/-19.3 yrs, and Acute Physiology and Chronic Health Evaluation II score (mean +/- SD) 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 High 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.

[1]  V Torri,et al.  Effectiveness of antibiotic prophylaxis in critically ill adult patients: systematic review of randomised controlled trials , 1998, BMJ.

[2]  G. Guyatt,et al.  A comparison of sucralfate and ranitidine for the prevention of upper gastrointestinal bleeding in patients requiring mechanical ventilation. Canadian Critical Care Trials Group. , 1998, The New England journal of medicine.

[3]  S. Chevret,et al.  Oropharyngeal or gastric colonization and nosocomial pneumonia in adult intensive care unit patients. A prospective study based on genomic DNA analysis. , 1997, American journal of respiratory and critical care medicine.

[4]  D. Hinthorn,et al.  Intermittent enteral feeding in mechanically ventilated patients. The effect on gastric pH and gastric cultures. , 1996, Chest.

[5]  D. Cook,et al.  Do critically ill patients tolerate early intragastric enteral nutrition , 1996 .

[6]  G. Guyatt,et al.  Stress ulcer prophylaxis in critically ill patients. Resolving discordant meta-analyses. , 1996, JAMA.

[7]  P. D. de Leeuw,et al.  Intermittent enteral feeding: the influence on respiratory and digestive tract colonization in mechanically ventilated intensive-care-unit patients. , 1996, American journal of respiratory and critical care medicine.

[8]  G. Divine,et al.  Prophylaxis for Stress-related Gastric Hemorrhage in the Medical Intensive Care Unit , 1994, Annals of Internal Medicine.

[9]  P. Francioli,et al.  Nosocomial Pneumonia in Mechanically Ventilated Patients Receiving Antacid, Ranitidine, or Sucralfate as Prophylaxis for Stress Ulcer , 1994, Annals of Internal Medicine.

[10]  M. Kollef.  The role of selective digestive tract decontamination on mortality and respiratory tract infections. A meta-analysis. , 1994, Chest.

[11]  R Jaeschke,et al.  Selective Decontamination of the Digestive Tract: An Overview , 1994 .

[12]  F. V. van Tiel,et al.  The stomach is not a source for colonization of the upper respiratory tract and pneumonia in ICU patients. , 1994, Chest.

[13]  P. Montravers,et al.  Nosocomial pneumonia in ventilated patients: a cohort study evaluating attributable mortality and hospital stay. , 1993, The American journal of medicine.

[14]  A. Hance,et al.  Evaluation of clinical judgment in the identification and treatment of nosocomial pneumonia in ventilated patients. , 1993, Chest.

[15]  L. Mandell,et al.  Effect of acidified enteral feedings on gastric colonization in the critically ill patient , 1992, Critical care medicine.

[16]  L. Mandell,et al.  Clinical Investigations in Critical CareGastric Colonization by Gram-Negative Bacilli and Nosocomial Pneumonia in the Intensive Care Unit Patient: Evidence for Causation , 1992 .

[17]  M. Tryba.  The gastropulmonary route of infection--fact or fiction? , 1991, The American journal of medicine.

[18]  J. Rello,et al.  Incidence, etiology, and outcome of nosocomial pneumonia in mechanically ventilated patients. , 1991, Chest.

[19]  R. Chang,et al.  Continuous enteral feeding: a major cause of pneumonia among ventilated intensive care unit patients. , 1990, JPEN. Journal of parenteral and enteral nutrition.

[20]  W. Zimmerli,et al.  Role of gastric colonization in nosocomial infections and endotoxemia: a prospective study in neurosurgical patients on mechanical ventilation. , 1989, The Journal of infectious diseases.

[21]  M. Niederman,et al.  Patterns and routes of tracheobronchial colonization in mechanically ventilated patients. The role of nutritional status in colonization of the lower airway by Pseudomonas species. , 1989, Chest.

[22]  F. Daschner,et al.  Stress Ulcer Prophylaxis and Ventilation Pneumonia Prevention by Antibacterial Cytoprotective Agents? , 1988, Infection Control &#x0026; Hospital Epidemiology.

[23]  B. Celli,et al.  Nosocomial pneumonia in intubated patients given sucralfate as compared with antacids or histamine type 2 blockers. The role of gastric colonization. , 1987, The New England journal of medicine.

[24]  M. Tryba.  Risk of acute stress bleeding and nosocomial pneumonia in ventilated intensive care unit patients: sucralfate versus antacids. , 1987, The American journal of medicine.

[25]  W. Knaus,et al.  APACHE II: a severity of disease classification system. , 1985 .

[26]  J. N. Hunt,et al.  The slowing of gastric emptying by four strong acids and three weak acids , 1972, The Journal of physiology.

[27]  S. Broitman,et al.  Gastric acid barrier to ingested microorganisms in man: studies in vivo and in vitro , 1972, Gut.