GASTRODUODENAL MOTILITY IN MECHANICALLY VENTILATED CRITICALLY ILL PATIENTS - A MANOMETRIC STUDY

Objective: To determine the main characteristics of gastroduodenal mot ility in mechanically ventilated,critically ill patients. Design: Case series; comparison with a parallel control group. Setting: Intensive care unit in a university teaching hospital. Patients: Twelve adult cr itically ill patients who required >2 days of mechanical ventilation a s a consequence of neurologic or respiratory disease. Control sample o f 12 overnight, fasting, healthy volunteers. Measurements and Main Res ults: Pressure changes in the gastric antrum, proximal duodenum, and d istal duodenum were simultaneously recorded during a 4-hr period by a multilumen tube (perfused catheter technique). The migrating motor com plex and its three successive phases were identified according to usua l definitions (phase 1, period of quiescence; phase 2, period of irreg ular contractile activity; phase 3 or activity front, period of high-f requency, regular contractions). Contractions and activity fronts at e ach site were quantified. The mean duration of the migrating motor com plex was determined in the duodenum, as well as the contribution of ea ch phase (phases 1, 2, 3) to the length of the complete cycle. The pro pagation characteristics of each activity front were assessed visually . In the patients, the number of contractions was markedly decreased i n the antrum, where activity fronts were totally absent. In the duoden um (proximal and distal), the number of contractions and the occurrenc e of activity fronts were comparable in both groups. Although the dura tion of the duodenal migrating motor complex was similar in the two gr oups, the relative contribution of the quiescence period (phase 1) to the total cycle length increased and the contribution of phase 2 decre ased in the patients. Three patients exhibited abnormally propagated ( retrograde or stationary) activity fronts in the duodenum. Conclusions : Gastroduodenal motility is severely impaired in this group of mechan ically ventilated patients. Activity fronts of the migrating motor com plex never originated in the stomach, which was hypokinetic; qualitati ve disorders of the migrating motor complex were present in the duoden um. The loss of peristaltic activity in the stomach and, to a lesser d egree, in the duodenum is consistent with an important role for motili ty disorders in the occurrence of digestive microbial overgrowth in su ch patients.