Toxicity after intermittent inhalation of nitrous oxide for analgesia

Abstract

A mixture of nitrous oxide and oxygen in equal proportions (Entonox or Equanox) is an effective analgesic and is considered safe with minimal side effects. The mixture is ideal for treating short term pain. We report a serious neurological problem in a patient using such a mixture to control pain from the daily packing of a large perineal cavity. Case reportA 21 year old man presented with a short history of being unable to stand. He had had a series of serious operations for the treatment for inflammatory bowel disease over a four year period-colectomy, ileostomy, and laparotomy with the formation of an ileoanal pouch. He developed pelvic sepsis requiring the laying open of an extensive perineal abscess.

The adverse effects of nitrous oxide

“…27 There are characteristic radiological findings. 28 A peripheral neuropathy and impaired brain function can also be part of the syndrome. Originally described predominantly in dentists who abused N 2 O, 29 most of the cases reported recently have been in patients who abused N 2 O.…”

Nitrous oxide. Should it still be used in pediatric medicine ? (Part 1)

“…The inhibition of methionine-synthetase thus can also results in interference with DNA synthesis in both leukocytes and erythrocytes [146]. Patients with sub-clinical B12 deficiency, because of illness, pernicious anemia, or nutritional deficiency, and patients with methylene-tetrahydrofolate-reductase deficiency are especially at risk [147]. Preoperative B12 followed by folate supplementation is recommended in such patients or N 2 O should in them be avoided.…”

Uso do óxido nitroso em pediatria

“…In patients with latent B 12 vitamin deficiency, myeloneuropatias, spastic paresthesia, acute funicular myeloid failure and psychiatric manifestations can be seen after exposure to nitrous oxide 87 (C). While the occurrence of neurological lesion is unlikely with a short-term exposure to nitrous oxide (as in a single surgical procedure), the reduction of methionine synthase activity after repeated exposures caused myelinopathy with medullar degeneration in humans 87 (C) and animals 88 (D).…”

“…While the occurrence of neurological lesion is unlikely with a short-term exposure to nitrous oxide (as in a single surgical procedure), the reduction of methionine synthase activity after repeated exposures caused myelinopathy with medullar degeneration in humans 87 (C) and animals 88 (D). Neurological lesions have also been described after anesthesia with nitrous oxide in patient with cobalamin 89 (C) or folate 90 (A) deficiency.…”

“…The effects of nitrous oxide on vitamin B 12 -dependent pathways in patients with deficiency of the methionine synthase enzyme are not known, but it seems reasonable to avoid its use in children with deficiency of this enzyme, as well as other B 12 vitamin metabolism defects 83,84,86,87,89 (C) 90 (A).…”