Intermittent enteral feeding: the influence on respiratory and digestive tract colonization in mechanically ventilated intensive-care-unit patients.

Continuous enteral feeding (CEF) has been associated with decreased gastric acidity, thereby stimulating gastric colonization and ventilator-associated pneumonia (VAP). Intermittent enteral feeding (IEF) could induce a temporary increase in gastric acidity and decrease the risk of VAP. We studied the influence of IEF (18 h/d) and CEF (24 h/d) on gastric and oropharyngeal colonization. Sixty patients were randomized to receive either IEF or CEF, and continuous intragastric pH monitoring was performed in 50 patients. Median intragastric pH levels were similar before enteral feeding was instituted (pH 2.5 for CEF and pH 2.4 for IEF), and median pH values increased slightly after institution of nutrition (NS). In patients receiving IEF, median pH decreased from 3.5 to 2.2 (p = 0.0002) when enteral feeding was discontinued. However, despite this, 80% of the patients in both study groups were colonized in the stomach after 7 d in study. In addition, colonization rates of the oropharynx and trachea, the incidence of VAP, and mortality were similar in both study groups. IEF was less well tolerated than CEF. We conclude that almost all patients receiving enteral feeding are colonized in the stomach with gram-negative bacteria. IEF resulted in a slight decrease in intragastric pH without influencing rates of colonization and infection of the respiratory tract.