Gastric acidity and duodenogastric reflux during nasojejunal tube feeding in mechanically ventilated patients

Objective: In order to prevent gastric microbial over-growth, which may complicate nasogastric feeding, administration of nutrients more distally into the gut has been advocated in intensive care patients, as it offers the advantage of keeping the stomach empty and acid. In this study, we assessed the impact of jejunal feeding upon gastic pH in a group of mechanically ventilated. critically ill patients, with special focus on duodenogastric reflux as a possible cause of gastric alkalinization juring jejunal nutrition. Design: Prospective experimental study. Setting: Multidisciplinary intensive carl unit of a university hospital. Patients and methods: Gastric FH was recorded by continuous pHmetry over a 4-h period of fasting followed ed by a 4-h period of nasojejunal feeding at 100 kcal/h in 21 mechanically ventilated, critically ill patients. To determine the contribution of duodenogastric reflux to modifications of gastric acidity, the diet was traced with [In-111] DTPA (pentetic acid) in 11 of these 21 patients; gastric contents were aspirated every 30 min, then analysed for measurement of radioactivity, glucose, and bile acid concentration. Measurements and results: Median intragastric pH increased slightly from 1.59 (1.20-2.73: interquartile range) (fasting) to 2.33 (1.65-1.64) (feeding) (p = 0.013), and the length of time that the PH was 4 or above increased from 1 (0-24) to 9 (0-142) min (p = 0.026). The variability of pH values and the number of acute alkalinization episodes did not change between the two phases. In 10 of 11 patients in which the diet was labeled with [In-111] DTPA. reflux was documented at a given time of the feeding period. Bile acid concentrations in the stomach increased from 392 (61-1076) (fasting) to 1446 (320-2770) mu mol/l(feeding) (p = 0.010) and mean glucose concentration increased from 59 (28-95) to 164 (104-449) mg/dl (p = 0.006). Conclusion: Duodenogastric reflux; is common in mechanically ventilated critically ill patients with nasojejunal feeding tubes. It occurs both during fasting and during nasojejunal feeding. During nasojejunal feeding, moderate alkalinization of the gastric contents occurs as a result of bile and nutrient reflux.