Prevention of Postoperative Nausea and Vomiting

Abstract

Postoperative nausea and vomiting (PONV) are common and unpleasant complications of anesthesia and surgery. The overall incidence rate of PONV for all surgical patients is estimated to be 25-30 %, while the rate of PONV in high-risk patients can be as high as 80 % [ 1 -4 ]. An estimated 0.18 % of patients experience intractable PONV, which may result in prolonged postanesthesia care unit (PACU) stay, unanticipated hospital readmission, and increased health care costs [ 5 -7 ]. PONV represents one of the most common reasons for poor patient satisfaction scores in the postoperative period [ 8 ]. One survey found that patients would be willing to pay up to $100, at their own expense, for complete and effective antiemetic treatment [ 9 ].The aim of this chapter will be to summarize the evidence for the implementation of PONV protocols within an enhanced recovery after surgery program (ERP). Literature used for these recommendations come from randomized control trials, meta-analyses, and consensus guidelines. We will address the following: identifying high-risk patients, minimizing risks, administering appropriate prophylactic antiemetic and rescue treatment, and recommending a treatment algorithm for use in an ERP protocol. Identifying High-Risk PatientsThere are several factors that have been associated with increased risk of PONV, but to effectively stratify risk, one should focus on those factors that independently predict PONV. These factors include female sex, history of PONV or motion sickness, nonsmoking status, younger 80 age, general versus regional anesthesia, use of volatile anesthetics and nitrous oxide, postoperative opioids, duration of surgery, and type of surgery (cholecystectomy, laparoscopic, gynecological) [ 10 ]. The increased incidence of PONV with laparoscopic surgeries and cholecystectomies is particularly relevant when considering ERP protocols for gastrointestinal surgery [ 11 ]. To ease the task in risk stratification, Apfel et al.[ 1 ] developed a simplified risk score, based on four predictors: female gender, history of motion sickness or PONV, nonsmoking status, and the use of opioids for postoperative analgesia. The incidence of PONV in patients with 0, 1, 2, 3, or 4 of these risk factors was 10, 21, 39, 61, and 79 % respectively (Fig. 8.1 ) [ 1 ]. The use of this simplified risk score to guide therapeutic interventions has been shown to dramatically reduce institutional rates of PONV [ 12 -14 ] (Fig. 8.2 ). Reducing Baseline RisksThere are several strategies that can be used to reduce the baseline risk of PONV: Avoiding general anesthesia by the use of regional anesthesia; Using propofol, an antiemetic in its own right, for induction and maintenance of anesthesia; Avoiding nitrous oxide; Avoiding volatile anesthetics; Minimizing intraoperative and postoperative opioids; and adequate hydration [ 10 ]. The complete avoidance of general anesthesia is not generally practical for gastrointestinal surgery; however, the use of transversus abdominis plane (TAP) blocks as part of the analgesi...