NO INHIBITION OF GASTROINTESTINAL PROPULSION AFTER PROPOFOL-N2O O-2 OR PROPOFOL/KETAMINE-N2O/O-2 ANESTHESIA - A COMPARISON OF GASTRO-CECAL TRANSIT AFTER ISOFLURANE ANESTHESIA/

Background: Gastrointestinal motility may be considerably reduced by a naesthesia and or surgery resulting in postoperative ileus. Inhibition of propulsive gut motility is especially marked after an opioid-based technique. Little, however, is known of the gastrointestinal effects of the hypnotic propofol when given continuously over a longer period of time, which is the case in total intravenous anaesthesia (TIVA) and in intensive care sedation. Mie therefore set out to study the effect s of a propofol-based nitrous oxide/oxygen anaesthesia (group PO) on g astro-caecal transit time. The results were compared with a propofol-k etamine technique (group PK) and an isoflurane-based anaesthesia (grou p I; each group n=20). Methods: Gastro-caecal transit was determined b y measurement of endexpiratory hydrogen concentration (ppm). Following gastral installation of lactulose at the end of the operation, the di sacchharide was degraded by bacteria in the caecum, resulting in the l iberation of hydrogen which was expired. A 100% increase in endexpirat ory hydrogen concentration compared to the preinduction period was con sidered the end-Feint of gastrocaecal transit. Results: There was no s ignificant difference with regard to gastro-caecal transit in the thre e groups of patients. In the propofol group mean gastro-caecal transit was 119 (+/-50.6 SD) min, in the propofol-ketamine group it was 147 ( +/-57.4 SD) min, and in the isoflurane group transit time was 122 (+/- 48.6 SD) min. Conclusion: The data suggest that propofol, even when gi ven as a continuous infusion, does not alter gastrointestinal tract mo tility more than a standard isoflurane anaesthesia. The data may be pa rticularily relevant to patients who are likely to develop postoperati ve ileus. They also suggest that in an ICU setting propofol does not a lter gut motility more than a sedation technique with the analgesic ke tamine.