Propofol and gastric effects of morphine

OBJECTIVE: The purpose of this study was to evaluate whether propofol abolishes morphine-induced effects on gastric emptying and gastric tone. METHOD: The study was carried out before anesthesia in 40 patients (ASA I-II). Gastric tone was measured in 20 patients by an electronic barostat. Volume changes were thereby registered continuously in an intragastric flaccid bag with a constant preset pressure. All patients received i.v. morphine 0.1 mg x kg(-1) before the measurements and, in a randomized order, 10 of the patients also received a bolus dose of propofol 1 mg. kg-1 before morphine. Gastric emptying was studied with the paracetamol method in 20 patients. All patients received morphine 0.1 mg x kg(-1) i.v. 10 min before oral ingestion of 1.5 g paracetamol in 200 ml water and, in a randomized order, 10 of the patients also received propofol, a bolus dose of 0.3 mg x kg(-1) before morphine, followed by an infusion of 1 mg x kg(-1) x h(-1) during the whole study (2 h). RESULTS: The volume in the intragastric bag increased in all patients receiving morphine without propofol. In the group that received propofol before morphine, the volume in the intragastric bag decreased in all patients. The volume differences between the groups were statistically significant (P<0.01). There were no statistically significant differences of the AUC60, Cmax and Tmax of serum paracetamol concentrations between the morphine and propofol-morphine groups. CONCLUSION: Propofol did not abolish morphine-induced delay of gastric emptying even if propofol abolished the decrease of gastric tone induced by morphine.