Introduction: Post-operative nausea and vomiting (PONV) is a common problem that is prevalent in over one-third of post-surgical patients 1.Patient surveys have indicated that patients consider emesis even more undesirable than pain 2. The purpose of this study was to evaluate the incidence of PONV and to identify risk factors and treatment strategies in non-cardiac adult post-operative patients in the post-anesthesia care unit (PACU).
Methods: The electronic medical records of 356 adult post-operative patients undergoing non-cardiac surgery from 5/1/2016 to 2/28/2017 at LAC+USC Medical Center were reviewed retrospectively looking at incidence of PONV. Risk factors recorded included 1) baseline patient risk factors such as inpatient vs. outpatient surgery, age, gender, ASA physical status, BMI, smoking history, 2) intra-operative risk factors such as types of surgery, modes of anesthesia, anesthesia duration, and intra-operative blood loss, and 3) PACU risk factors such as pain score on arrival, administration of post-operative opioids, and administration of anti-emetics.
Results: The overall incidence of post-operative nausea in the PACU at LAC+USC medical center was 5.6%.Risk factors such as female gender, age > 50, types of surgery (e.g. gynecological, oral maxillofacial), and prior history of PONV or motion sickness were predictive of PONV. In addition, in-patient surgeries, utilization of general anesthesia, longer anesthesia duration, and opioid administration in PACU were also associated with higher PONV rates. ASA physical status, estimated blood loss, type of intra-operative opioid administration, and PACU pain score on arrival showed no correlation with incidence of PONV.
Conclusion: Incidence of PACU PONV categorized according to peri-operative risk factors largely confirmed many of the PONV risk factors as defined by Gan et al. The overall incidence of PACU post-operative nausea at LAC+USC was 5.6% and vomiting 0% compared to the incidence reported by Gan et al. in meta-analysis studies of 50% for nausea and 30% for vomiting for various post-operative periods (1). This may be due to factors such as the use of intra-operative prophylactic anti-emetic agents, utilization of alternative modes of anesthesia to reduce PONV, and under-reporting of PONV. Future research may look into risk-benefit and cost analysis of prophylactic anti-emetic agents, uncovering methods of better characterizing and reporting PONV, and correlation with aforementioned predisposing risk factors for PONV in randomized prospective controlled trials.
References: 1.Gan, Tong et al. “Consensus Guidelines for the Management of Postoperative Nausea and Vomiting.” Anesthesia and Analgesia, Volume 118, Issue 1, 2014, 85-113.
2. Macario A, Weinger M, Carney S, Kim A. Which clinicalanesthesia outcomes are important to avoid? The perspective of patients. AnesthAnalg 1999;89:652–8.
3. Apfel CC, Läärä E, Koivuranta M, Greim CA, Roewer N. Asimplified risk score for predicting postoperative nausea and vomiting:conclusions from cross-validations between two centers. Anesthesiology1999;91:693–700
