GASTROINTESTINAL MOTILITY AND GASTRIC TUBE-FEEDING IN MECHANICALLY VENTILATED PATIENTS

Objective: To determine the fasted and fed gastrointestinal motility c haracteristics that are possibly responsible for gastric retention in mechanically ventilated patients. Design: Prospective, case series. Se tting: Surgical intensive care unit of a university hospital. Patients : Seven patients who required mechanical ventilation for thoracic or c ombined thoracic-neurologic injuries and nine healthy volunteers. Inte rventions: None. Measurements and Main Results: Antroduodenal manometr y was performed during fasting and gastric feeding with a polymeric di et in patients during mechanical ventilation, weaning, and after detub ation. Gastric retention volumes were determined during gastric tube f eeding. Motility data were compared with recordings from nine healthy volunteers. During the fasting state, under sedation and morphine, the migrating motor complex in patients was significantly (p <.001) short ened: median 32.0 vs. 101.0 mins in healthy volunteers. During gastric tube feeding, the motility pattern did not convert to a normal postpr andial pattern until morphine was discontinued. An interdigestive or m ixed interdigestive-postprandial pattern was seen during gastric tube feeding in most patients during morphine administration. Most (94%) of the activity fronts during gastric feeding started in the duodenum. G astric retention percentages during gastric tube feeding were negative ly correlated (r(2) =.44; p<.01)with antral motor activity. Conclusion s: These data suggest that morphine administration affects antroduoden al motility in mechanically ventilated patients. The gastrointestinal motor pattern involved in impaired gastric emptying in morphine-treate d patients is characterized by antral hypomotility and persisting duod enal activity fronts during continuous intragastric feeding. The obser ved motility patterns suggest that early administration of enteral fee ding might be more effective into the duodenum or jejunum than into th e stomach of mechanically ventilated patients. (Crit Care Med 1998; 26 :15101517).