Prevalence and time course of postoperative nausea and vomiting and severe pain in patients under general anesthesia with patient-controlled intravenous analgesia.

Introduction: Postoperative nausea and vomiting (PONV) and pain are common and distressing complications in patients undergoing surgery. However, it remains uncertain whether timing of the postoperative course or the diel rhythm influences the occurrence of PONV or severe pain. Therefore, we aimed to explore the temporal distribution of PONV and severe pain. Material and methods: In this prospective observational study, we enrolled patients aged 18-65 years with American Society of Anesthesiologists classifications I-III, who were scheduled for surgery under general anesthesia. Patients were visited postoperatively at regular intervals (every 6 h over a 24-h period). Incidence of PONV was recorded and categorized based on real-time divisions: before dawn (00:00-05:59), morning (06:00-11:59), afternoon (12:00-17:59), and evening (18:00-23:59) and as sequential periods (i.e., 0-6, 6-12, 12-18, and 18-24 h). Severe pain and use of additional remedies were also recorded. Results: A total of 724 patients were included in the final analysis. Of these, 14.92 % experienced PONV within the first 6 h, and 8.29 % received antiemetic therapy. Occurrence of PONV and administration of remedies declined over the 24-h postoperative period. The lowest rate of PONV was observed during the pre-dawn hours (5.66 %). There was no statistically significant difference in the incidence of PONV 24-h postoperatively between surgeries with different end times. Patients underwent orthopedic surgeries had the highest incidence of PONV during 18:00-23:59, gynecological surgery patients had the highest incidence at 12:00-17:59, and 6:00-11:59 for other surgery patients. All patients had the lowest incidence during 0:00-5:59. During the initial 6-h postoperative period, 24.59 % of patients experienced severe pain, which declined in the remaining episodes. Patients who underwent orthopedic and gynecological surgeries exhibited similar temporal patterns and distribution characteristics of PONV and severe pain. Discussion: Both PONV and severe pain declined within the 24-h postoperative period, particularly within the first 6 h. Additionally, the onset patterns of PONV vary among patients undergoing different types of surgeries, all patients demonstrated decreased susceptibility to PONV between 00:00-05:59. Our findings enhance prevention and treatment strategies within an optimized timeframe during the postoperative course.