['To investigate the effect of cisapride, a relatively new prokinetic agent, on gastric emptying in critically ill patients.', 'Prospective, randomized, controlled study.', 'Adult medical/surgical intensive care unit in a university hospital.', 'Twenty-one consecutively enrolled patients, requiring prolonged mechanical ventilation and enteral feeding.', 'Patients were randomized to receive either no cisapride or 10 mg of cisapride four times daily, which was added to a standard enteral nutrition feeding protocol.', 'Gastric emptying was evaluated by daily measurements of gastric residue and on days 5 through 7 by bedside scintigraphy. Normal values for gastric clearance of a tracer-labeled test meal and for measurements obtained in the supine position were determined in ten healthy volunteers. The mean time at which 50% of the technetium 99m-labeled test meal was eliminated from the stomach (T 1/2) in this control group was 31 +/- 15 mins. In ten critically ill patients (enteral nutrition group), gastric emptying was markedly delayed after 5 to 7 days of enteral feeding (mean T 1/2 = 78 +/- 40 mins; p < .002 as compared with the control group). In contrast, patients treated with cisapride (cisapride group) showed an accelerated gastric emptying (mean T 1/2 = 18 +/- 7 mins; p > .05 as compared with controls; p < .005 as compared with enteral nutrition group). The mean gastric residue over a 1-wk period was also significantly lower in the cisapride group than in the enteral nutrition group (17.7 +/- 8.9 vs. 94.5 +/- 33.4 mL; p < .001).'] Is gastric emptying in critically ill patients accelerated by adding cisapride to a standard enteral feeding protocol : results of a prospective , randomized , controlled trial?