Factors associated with vomiting in orthopedic patients receiving patient-controlled epidural analgesia

Background: Although patient-controiled epidural analgesia (PCEA) can effectively relieve postoperative pain in orthopedic patients, some adverse effects are still troublesome. We conducted this study to survey the possible risk factors related to vomiting induced by PCEA. Methods: This retrospective study was conducted to review orthopedic patients receiving postoperative PCEA. The agent for PCEA was bupivacaine prepared as a 0.1% solution with added fentanyl (1 μg/mL). Patients' characteristics including demographic data and types of surgical procedures were collected. All patients were dichotomized into vomiting and non-vomiting groups and subgroup comparisons were also performed. Stepwise logistic regression analyses were conducted to determine significant factors associated with vomiting in these patients. Results: There were 320 patients (111 men, 209 women) included in the analysis. No significant differences in demographic data were noted between the groups except in sex distribution. Factors related to surgery, anesthesia and PCEA were similar between groups (p>0.05 in all). The incidence of vomiting for orthopedic patients receiving PCEA was about 9.7% (12.4% for female, 4.5% for male). After stepwise model selection, we found female sex was the only risk factor of vomiting. The odds ratio of vomiting for female gender was 3 (95% confidence interval, 1.1-8.1). General anesthesia was not associated with vomiting in these patients. Conclusion: Our study demonstrated the risk factor associated with vomiting for orthopedic patients receiving PCEA was female sex. Other demographic variables and factors related to surgery or anesthesia did not have an influence on vomiting.