Nitrous oxide gastrointestinal

The metabolism of enflurane and sevoflurane results in the formation of fluoride ion. However, in contrast to the rarely used volatile anesthetic methoxyflurane, renal fluoride levels do not reach toxic levels under normal circumstances. In addition, sevoflurane is degraded by contact with the carbon dioxide absorbent in anesthesia machines, yielding a vinyl ether called "compound A," which can cause renal damage if high concentrations are absorbed. (See Do We Really Need Another Inhaled Anesthetic ) Seventy percent of the absorbed methoxyflurane is metabolized by the liver, and the released fluoride ions can produce nephrotoxicity. In terms of the extent of hepatic metabolism, the rank order for the inhaled anesthetics is methoxyflurane > halothane > enflurane > sevoflurane > isoflurane > desflurane > nitrous oxide (Table 25-2). Nitrous oxide is not metabolized by human tissues. However, bacteria in the gastrointestinal tract may be able to break down the nitrous oxide molecule. 

Occasionally, gastrointestinal disorders have been related to the use of hemoglobin-based oxygen carriers, possibly through binding of nitrous oxide, causing gastrointestinal smooth muscle spasm (9,20). 

Kidney, Liver, and Gastrointestinal Tract Nitrous oxide is neither nephrotoxic nor hepatotoxic. 

Welchman S, Cochrane S, Minto G, Lewis S. Systematic review the use of nitrous oxide gas for lower gastrointestinal endoscopy. Aliment Pharmacol Ther 2010 32(3) 324-33. 

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