Avoid common mistakes on your manuscript.
To the Editor,
We appreciate Drs Mraovic, Timko, and Simurina’s expertise and comments on our paper.1,2 Our group reported that nitrous oxide (N2O) use had the beneficial effect of decreasing postanesthesia care unit (PACU) length of stay (LOS). We observed a dose-dependent effect that was already relevant when N2O was used only at the end of the case (resulting in a very low median N2O concentration).
Our data support Dr. Mraovic’s assumption that N2O administration reduces PACU LOS. Our findings revealed that patients who received N2O had a shorter duration of intraoperative hypotension; the increased hemodynamic stability was associated with a reduction of PACU LOS. Dr. Mraovic also emphasized the opioid-sparing effect of N2O,3 which also may help reduce PACU LOS.4 Our data indeed show that intraoperative opioid use was lower in patients who received higher doses of N2O.
Our data suggest that there are competing effects of N2O that affect PACU length of stay: increased hemodynamic stability and increased postoperative nausea and vomiting. We found that N2O increased the risk of postoperative nausea and vomiting (adjusted odds ratio, 1.24; 95% confidence interval, 1.14 to 1.34; P < 0.001) which was associated with an estimated increase in PACU LOS of more than one hour. Of note, these negative effects were not observed in patients who received intraoperative antiemetic prophylaxis, which supports a previous report.5
In summary, we found that N2O can help reduce LOS in the PACU. This effect is more relevant in patients who have undergone complex surgery, and those who are at a higher risk of intraoperative hemodynamic instability and often get higher opioid doses. Clinicians who use N2O should always coadminister antiemetic drugs.
References
Mraovic B, Timko NJ, Simurina T. Nitrous oxide and length of stay in the postanesthesia care unit. Can J Anesth 2022. https://doi.org/10.1007/s12630-022-02284-3.
Obeidat SS, Wongtangman K, Blank M, et al. The association of nitrous oxide on length of stay in the postanesthesia care unit: a retrospective observational study. Can J Anesth 2021; 68: 1630–40. https://doi.org/10.1007/s12630-021-02067-2
Roth J V. Chronic pain and the opioid epidemic: are we ignoring the potential benefits of nitrous oxide? Anesth Analg 2018; 126: 1423–4. https://doi.org/10.1213/ANE.0000000000002710
Mraovic B, Simurina T, Gan TJ. Nitrous oxide added at the end of isoflurane anesthesia hastens early recovery without increasing the risk for postoperative nausea and vomiting: a randomized clinical trial. Can J Anesth 2018; 65: 162–9. https://doi.org/10.1007/s12630-017-1013-y
Myles PS, Chan MT, Kasza J, et al. Severe nausea and vomiting in the evaluation of nitrous oxide in the gas mixture for anesthesia II trial. Anesthesiology 2016; 124: 1032–40. https://doi.org/10.1097/ALN.0000000000001057
Disclosures
Matthias Eikermann has received unrestricted funds from philanthropic donors Jeffrey and Judy Buzen and grants from Merck & Co. outside of the submitted work. Karuna Wongtangman and Michael Blank declare no conflicts of interest.
Funding statement
None.
Editorial responsibility
This submission was handled by Dr. Philip M. Jones, Deputy Editor-in-Chief, Canadian Journal of Anesthesia/Journal canadien d’anesthésie.
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Wongtangman, K., Blank, M. & Eikermann, M. In reply: Nitrous oxide can help reduce length of stay in the postanesthesia care unit. Can J Anesth/J Can Anesth 69, 1180–1181 (2022). https://doi.org/10.1007/s12630-022-02285-2
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12630-022-02285-2