Background: Gastrointestinal motility may be considerably reduced by anaesthesia 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. We therefore set out to study the effects of a propofol-based nitrous oxide/oxygen anaesthesia (group PO) on gastro-caecal transit time. The results were compared with a propofol-ketamine technique (group PK) and an isoflurane-based anaesthesia (group I; each group n=20).
Methods: Gastro-caecal transit was determined by measurement of endexpiratory hydrogen concentration (ppm). Following gastral installation of lactulose at the end of the operation, the disacchharide was degraded by bacteria in the caecum, resulting in the liberation of hydrogen which was expired. A 100% increase in endexpiratory hydrogen concentration compared to the preinduction period was considered the end-point of gastrocaecal transit.
Results: There was no significant difference with regard to gastro-caecal transit in the three 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 given as a continuous infusion, does not alter gastrointestinal tract motility more than a standard isoflurane anaesthesia. The data may be particularity relevant to patients who are likely to develop postoperative ileus. They also suggest that in an ICU setting propofol does not alter gut motility more than a sedation technique with the analgesic ketamine.