Is Postoperative Nausea and Vomiting Associated With Increased Postoperative Pain in Patients Undergoing Minor Oral and Maxillofacial Surgery Under General Anesthesia?

BACKGROUND: Whether postoperative nausea and vomiting (PONV) contributes to increased postoperative pain (POP) remains unclear, although POP is reported to cause PONV. PURPOSE: This study aimed to determine whether PONV following minor oral and maxillofacial surgery (OMS) under general anesthesia increases POP. STUDY DESIGN, SETTING, SAMPLE: The researchers implemented a retrospective cohort study. Patients who presented to Saitama Medical University Hospital between January 2021 and August 2022 and who required minor OMS under general anesthesia were identified from a review of electronic records. The inclusion criteria were patients aged between 16 and 65 years and nasal intubation via inhalational or propofol-based total intravenous general anesthesia. The exclusion criterion was patients who had diseases affecting POP or PONV. PREDICTOR VARIABLES: The primary predictor variable was the occurrence of PONV (yes/no) at 2 hours postoperatively. MAIN OUTCOME VARIABLES: The main outcome variable was POP measured on a 100 mm visual analog scale (VAS) at 2 hours postoperatively. The secondary outcome was the timing of POP, which was measured at 6 hours. COVARIATES: Covariates included patient-related factors (age, body mass index, American Society of Anesthesiologists Physical Status, smoking status, and history of PONV or motion sickness), anesthesia-related factors (intraoperative analgesics, intraoperative antiemetics, duration of anesthesia, and anesthesia type), and surgery-related factors (surgery type and duration of surgery). ANALYSES: Analyses were used for ordinal, categorical, and continuous variables. The POP VAS values were compared between each measurement time with repeated-measures analysis of variance. A P value < .05 indicated statistical significance. RESULTS: The sample included 148 patients with a mean age of 40 +/- 16.5 years, 66 (44.6%) of whom were male. The incidence of PONV was 31 (20.9%) at 0 to 2 hours, 7 (4.7%) at 2 to 6 hours, and 0 (0%) at 6 to 24 hours. POP VAS scores were significantly higher in the PONV group than in the non-PONV group at 2 hours. The mean VAS score at 2 hours was 40.5 +/- 29.2 (PONV group) versus 29.8 +/- 23.7 (non-PONV group) (P = .03); the VAS score at 6 hours was 41.0 +/- 29.4 (PONV group) compared with 25.4 +/- 26.4 (non-PONV group) (P = .13). CONCLUSION: Our present study revealed that PONV is associated with increased POP in patients undergoing minor OMS under general anesthesia.