Diffusion of xenon and nitrous oxide into the bowel

Background: Nitrous oxide diffuses easily from blood into air filled spaces . Xenon is also a relatively insoluble gas, like nitrous oxide. Therefore, the authors measured xenon diffusion into obstructed bowel segments during xenon anesthesia and compared this with nitrous oxide and nitrogen diffusio n. Methods: Twenty-one pentobarbital-anesthetized pigs were randomly assigned to three groups to receive either xenon-oxygen, nitrous oxide-oxygen, or ni trogen-oxygen (75%-25%, respectively. In each animal, four bo Fc el segment s of 15-cm length were Isolated. A pressure-measuring catheter was inserted into the lumen, and 30 ml of room air was injected into the segments, Anes thesia with the selected gas mixture was performed for 4 h, Pressure in the segments was measured continuously. The volume of gaseous bowel content wa s measured on completion of the study. Results: The median volume of bowel gas in animals breathing nitrous oxide was 88.0 ml as compared with 39.0 ml with xenon anesthesia and 21.5 ml in t he nitrogen-oxygen group. After 4 h of anesthesia, thr intraluminal pressur es in the nitrous oxide group were found to be significantly greater than i n the control group and in the xenon group. Conclusions: The amount of diffused gas was significantly lower during xeno n anesthesia than with nitrous oxide anesthesia hut greater than with contr ols. Blood solubility carl therefore be regarded as an important factor inf luencing gas diffusion into air filled cavities,