The Effect of Nitrous Oxide Anesthesia on Early Postoperative Opioid Consumption and Pain

Abstract

Background and Objectives Many patients experience moderate to severe postoperative pain. Nitrous oxide exerts analgesia by inhibition of N-Methyl-D-aspartate (NMDA) receptors. Ketamine, another NMDA receptor-antagonist, reduces postoperative opioid consumption and pain. A similar effect of nitrous oxide is plausible, yet understudied. The goal of this study was to determine the effects of nitrous oxide anesthesia on early postsurgical opioid consumption and pain. Methods This was a retrospective, secondary analysis of the Vitamins In Nitrous Oxide trial, where 500 patients undergoing general anesthesia for noncardiac surgery received 60% nitrous oxide and 125 received no nitrous oxide (otherwise, inclusion/exclusion criteria were identical). Exclusion criteria for this study were regional anesthesia; not extubated after surgery; transfer to ICU; no available PACU record; postsurgical sedation; or treated with naloxone. Primary outcomes were cumulative opioid consumption measured in morphine equivalents and pain scores during the immediate recovery phase. Results Four hundred forty-two patients met inclusion criteria. No difference in intraoperative and postoperative opioid consumption was observed between patients who received nitrous oxide (n=353) and patients who did not (n=89). The median [interquartile range] postoperative morphine equivalent dose was 6.7 mg [1.7–14.1] for patients who received nitrous oxide and 6.7 mg [2.1–15.4] for patients who did not (P = 0.73). The maximum pain score was 6 [4–8] for patients who received nitrous oxide versus 6 [3–8] for patients who received nitrous oxide-free anesthesia (P = 0.52). The prevalence of moderate to severe pain was 69% for patients who received nitrous oxide and 68% for patients who did not (P = 0.90). Conclusions Nitrous oxide anesthesia was not associated with decreased opioid administration, pain, or incidence of moderate to severe pain in the early postoperative phase.

Chronic pain relief after the exposure of nitrous oxide during dental treatment: longitudinal retrospective study

“…The doses of analgesic drugs can be reduced after the use of nitrous oxide during surgical procedures 4,5,6,7,8,9,10,11,12,13,14 . The development of chronic pain after surgeries can also be prevented with this type of sedation 17 .…”

Effect of applying cold gel pack on reduction of postoperative pain in cesarean section, low midline skin incision: A randomized controlled trial

“…After the operation, the participants received intravenous 25–50 mg of meperidine or tramadol if VAS score was 4 or greater according to standard regimens of anesthesiologists. Opioid dose was converted by an equianalgesic conversion table to morphine and recorded, where intravenous meperidine 75 mg and tramadol 100 mg is equivalent morphine 10 mg 9 . The intervention group additionally received cold gel pack administration whereas the control group did not.…”

Evaluation of antihyperalgesic and analgesic effects of 35% nitrous oxide when combined with remifentanil

“…N 2 O is a NMDA receptor antagonist [14][15][16] and it was reported that N 2 O has similar beneficial antihyperalgesic properties to those of the NMDA receptor antagonist ketamine to block OIH in animal models. 17,18 Animal and patient studies indicate that N 2 O leads to a negative modulation of the nociceptive processes at spinal cord level, [19][20][21] is able to block the development of OIH in postoperative pain, 18,[22][23][24][25] reduces postoperative opioid consumption 26 and it is assumed that it reduces postoperative chronic pain. [23][24][25] A previous phase 1 study demonstrated in a human pain model of central sensitisation that the combination of 50% N 2 O and remifentanil significantly reduced the amount of remifentanil-induced hyperalgesia (RIH), allodynia and pain sensitivity developed after administration of remifentanil alone.…”