Vomiting nitrous oxide

Nitrous oxide is associated with postoperative nausea and vomiting. This probably involves both central and peripheral mechanisms, the latter is the result of distension of the gut due to rapid movement of nitrous oxide into the lumen. It is possible that better operating conditions are achieved when nitrous oxide is avoided. 

Many of the drugs used in modern anaesthetic practice have an effect on the CT7 and vomiting centre either directly or indirectly, e.g. stimulation of the vestibular apparatus, stimulation of the CTZ by opioid agonist drugs, and an anti-emetic effect of propofol or emetogenic effect of nitrous oxide. Propofol... 

Nitrous oxide may cause gut distension and also increase middle ear pressure, leading to stimulation of the vestibular apparatus. Thus, it is associated with a very slight increase in the incidence of nausea and vomiting. 

The chemical structures of the currently available inhaled anesthetics are shown in Figure 25-2. The most commonly used inhaled anesthetics are isoflurane, desflurane, and sevoflurane. These compounds are volatile liquids that are aerosolized in specialized vaporizer delivery systems. Nitrous oxide, a gas at ambient temperature and pressure, continues to be an important adjuvant to the volatile agents. However, concerns about environmental pollution and its ability to increase the incidence of postoperative nausea and vomiting (PONV) have resulted in a significant decrease in its use. 

Adverse effects. The incidence of nausea and vomiting increases with the duration of anaesthesia. Nitrous oxide interferes with the synthesis of methionine, deoxythymidine and DNA. Exposure of to nitrous oxide for more than 4 hours can cause megaloblastic changes in the bone marrow. Because prolonged and repeated exposure of staff as well as of patients may be associated with bone-marrow depression and teratogenic risk, scavenging systems are used to minimise ambient concentrations in operating theatres. 

Visser K, Hassink EA, Bonsel GJ, Moen J, Kalkman CJ. Randomized controlled trial of total intravenous anesthesia with propofol versus inhalation anesthesia with iso-flurane-nitrous oxide postoperative nausea with vomiting and economic analysis. Anesthesiology 2001 95(3) 616-26. 

Nausea and vomiting seldom occur. Nitrous oxide had no effect on recovery from laparoscopic cholecystectomy (35). 

Overall, about 10% of patients have unpleasant but usually transient adverse reactions. Xenon is a narcotic gas, more potent than nitrous oxide, and inhalation of 71% xenon is sufficient for anesthesia in 50% of patients. Lower concentrations of xenon are currently used, but some euphoric or dysphoric effects are still observed and can cause temporary exacerbation of neuropsychiatric symptoms. Mild nausea can also occur, and patients should have an empty stomach before the scan to reduce the risk of vomiting and possible aspiration. Very rarely, apnea can occur and can be... 

The subjective, psychomotor, and physiological properties of subanesthetic concentrations of xenon have been studied in 10 volunteers (3). Xenon sedation was well tolerated and was not associated with any adverse physiological effects. In particular, there was no nausea or vomiting. It was preferred to sedation with nitrous oxide and was subjectively dissimilar (xenon was more pleasant). 

Adverse effects reported from nitrous oxide use have included nausea, vomiting, and headache. In addition, heavy chronic use has occasionally been reported to resemble the sort of dependence that develops with other depressant drugs. With hca y use come more severe problems, including numbness of the extremities and permanent peripheral nerve damage. There have also been some reports of death by asphyxiation after using large amounts in a poorly ventilated space (Walker Zacny, 2005). 

After the war, when the number of "cannabis poisonings" began to attract notice, physicians found themselves in a quandary as to how to treat these drag oveidosings. Many recommended forced vomitings to be followed by hot coffee, lemon juice, ammonia, strychnine, atropine, or nitrous oxide. Some physicians also recommended electric shock and artificial respiration. 

Finally, nitrous oxide is not used in the United States but is a common analgesic in many developed countries. A 50-50 blend of nitrous oxide and oxygen is the most commonly used mixture. Women can self-administer the medication or receive it continuously under medical supervision. Women report significant pain relief. The side effects include nausea, vomiting, and poor recall of labor. ... 

Inhalation. People acutely exposed to high levels of nitrous oxide should be immediately removed fi-om exposure, after which symptoms should rapidly reverse. If obtundation (dulling or blunting of sensitivity, such as to pain) is present, oxygen should be administered. Mechanical ventilation should be instituted in the event of respiratory arrest. Vomiting may occur as the person awakes. To prevent aspiration, exposed individuals should be placed on their side with their head at the level of or slightly lower than their body [6]. 

Leslie K, Myles PS, Chan MT, Paech MJ, Peyton P, Forbes A, McKenzie D. ENIGMA Trial Group. Risk factors for severe postoperative nausea and vomiting in a randomized trial of nitrous oxide-based vs. nitrous oxide-free anaesthesia. Br J Anaesth 2008 101(4) 498-505. 

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