Recovery profile of desflurane with air or nitrous oxide in patients undergoing general anesthesia - A prospective cohort study.

Background and aims: Desflurane helps in prompt awakening when discontinued. Since desflurane has a lesser blood: gas solubility than nitrous oxide, we hypothesized that use of air with desflurane would result in a rapid recovery compared to desflurane with nitrous oxide.

Materials and methods: After approval from the institutional ethical committee was obtained, this prospective, nonrandomized study (CTRI/2017/11/010558) was conducted. This study included 110 American Society of Anesthesiologists I-II patients aged 18-60 years, of either sex, undergoing general anesthesia using desflurane with air or nitrous oxide for elective surgery. The primary objective was to compare the time taken to achieve a modified Aldrete score of 9/10. The secondary objectives were to compare time to spontaneous respiration, time to extubation, time to verbal response, time to orientation, intraoperative opioid consumption, and incidence of explicit recall between groups. P <0.05 was considered significant.

Results: The time required to achieve modified Aldrete score of 9/10 was higher in those who received nitrous oxide (899.09 ± 426.85 s) compared to those who received air (464.27 ± 190.28 s; P < 0.01). Time taken for spontaneous respiration, extubation, verbal response, and orientation was significantly higher with the use of desflurane with nitrous oxide compared to use of air. The intraoperative opioid requirement was statistically significant, but clinically not significant. Explicit recall was not seen in any of the patients.

Conclusion: Nitrous oxide delays the elimination of desflurane compared to air, thus delaying extubation and recovery and mitigating the beneficial effects of desflurane.