Implications of Postoperative Nausea and Vomiting
Despite widespread use of prophylactic agents and short-acting anesthetics, postoperative nausea and vomiting (PONV) remains a common complication following surgery and anesthesia,1 and remains the “big little problem” of the postsurgical setting.2
An estimated 25% to 30% of all adult surgical patients and as many as 70% to 80% of high-risk patients develop PONV.3 For reasons that are not well understood, the incidence of PONV in children increases from 5% during infancy to approximately 40% in puberty.3 Furthermore, PONV is not restricted to the immediate postoperative period. One study found that more than 35% of patients who did not experience PONV in the post-acute care unit (PACU) report PONV symptoms up to 5 days postoperatively following hospital discharge.4
The etiology of PONV is complex and multifactorial, and involves a host of patient-, medical-, and anesthesia-related risk factors.3 While advances have been made in understanding the triggers behind emetic episodes, potential causes of nausea remain poorly understood.
PONV can have long-term implications for a patient to return to normal daily activities after surgery; it can lead to electrolyte imbalance, dehydration, pulmonary aspiration, and other complications,1 resulting in delayed hospital discharge5 and increased medical costs.6 The incremental ambulatory care cost of PONV/PDNV (post-discharge nausea and vomiting) has recently been estimated at $75.6 Research has shown that patients are willing to pay the extra cost of antiemetic treatment in order to avoid the distress and potential complications due to PONV.7
Patient-specific risk factors for PONV include female gender, young age, nonsmoking status, and history of PONV or motion sickness.1,8 It is not clear why women are at increased risk for PONV compared with men, although a link has been made between the timing of surgery during the menstrual cycle and risk for PONV.9 With respect to age, PONV is approximately twice as common in children as it is in adults.8 A history of motion sickness may also predispose a patient to PONV after surgery, due to vestibular changes occurring in response to sudden changes in position.8
Anesthesia-related risk factors for PONV include the use of opioid analgesics, volatile anesthetics, and nitrous oxide.1,3 A dose-dependent relationship has been demonstrated between postoperative opioid use and PONV.10 A systematic review of 22 prospective studies (n=95,154) found female gender, nonsmoking status, younger age, history of motion sickness or PONV, use of postoperative opioids, and duration of anesthesia with volatile anesthetics to be the most reliable independent predictors of PONV.11 In general, the chances of PONV increase with an increasing number of risk factors.12
The latest Consensus Guidelines for the Management of PONV (CGM-PONV) recommend an assessment of a patient’s baseline risk for PONV using a validated risk score based on independent predictors.13 One example is the Apfel score—a simplified risk score based on 4 predictors (female sex, nonsmoking status, postoperative opioid use, and history of PONV and/or motion sickness) used in patients undergoing anesthesia with volatile anesthetics.12