Impact of Changing the General Anesthesia Method on Postoperative Nausea and Vomiting Incident and Severity

Objective: Among patients who underwent general anesthesia (GA) multiple times with different methods, we aimed to compare the incidence and severity of postoperative nausea and vomiting (PONV) when the GA method was changed. Methods: Subjects were healthy intellectually disabled patients who underwent multiple dental procedures under GA. Methods of general anesthesia were classified as (1) nitrous oxide-sevoflurane (NOS), (2) sevoflurane-remifentanil (SRF), and (3) propofol-remifentanil (PRF). Patients who experienced PONV had an alternative method of GA utilized for subsequent cases. PONV incident rates and severity scores overall and between groups were calculated and compared statistically for analysis. Results: PONV occurred in 186 (6.5%) of the 2872 cases and in 85 (28.8%) of the 295 patients included in this study. Statistical paired comparisons of the mean incidence of PONV demonstrated a decrease of 25.2% when the GA method was changed from NOS to SRF, 40.4% when changed from NOS to PRF, and 36.4% when changed from SRF to PRF (P < .05). Statistical paired comparisons of the mean 5-point PONV severity score similarly demonstrated a decrease of 0.53 when the GA method was changed from NOS to SRF, 0.92 when changed from NOS to PRF, and 0.62 when changed from SRF to PRF (P < .05). Conclusion: The highest PONV incidence rates and severity were noted with NOS, whereas PONV decreased significantly with SRF and PRF use. The absence of nitrous oxide and use of propofol were suggested as ways to alter the method of general anesthesia to reduce the incidence and improve the severity of PONV.