General multimodal or scheduled risk-adopted postoperative nausea and vomiting prevention: just splitting hairs?

Worldwide, more than 230 million major surgical procedures are performed each year. For these patients, postoperative nausea and vomiting (PONV) are among the most frequently observed adverse events associated with the provision of general anaesthesia. It is distressing to patients and impairs the quality of recovery as judged by the patients and anaesthesiologists alike. 3 Our patients obviously dislike PONV and are willing to spend a considerable amount of money to eliminate the problem. 5 Decades ago, this clinical nuisance was named the ‘big little problem’ of anaesthesia, indicating that it may not be a big issue for anaesthesiologists, but it matters to our patients. When Patricia Kapur used the term ‘big little problem’, it was not entirely possible to eliminate PONV and the knowledge about the additive effects of antiemetics was still in its infancy. In the subsequent years, various drugs were investigated indepth by adequately powered randomized clinical trials 8 and meaningful meta-analyses; these drugs now constitute the core armamentarium of any anti-PONV algorithm. Finally, PONV has been among the most investigated adverse effects of the perioperative period. After Phil Scuderi’s statement with the title ‘Multimodal antiemetic management prevents early postoperative vomiting after outpatient laparoscopy’, the PONV community has been working on how to get rid of the ‘big little problem’. To achieve this goal, there is more thanone option toconsider. First, owing to the fact that the existing armamentarium consisting of low-dose corticosteroids (dexamethasone), ondansetron, a potent D2-antagonist (e.g. droperidol), antihistamines (e.g. dimenhydrinate), and NK-1 antagonists, and the omission of trigger factors by means of using a total i.v. anaesthesia, are considered relatively safe; so far, there is little indication to withhold these strategies for fear of sideeffects. Indeed, there is rationale to give more than one or two antiemetics to everybody as Scuderi recently pointed out in an editorial: ‘given the extremely low cost of all the currently available generic antiemetics and the extremely low incidence of adverse side-effects, I would suggest that all patients might benefit from 3 or more antiemetics during the course of surgery to reduce the incidence of PONV as much as possible’. The second principal option would be to tailor the therapeutic decisions to specific groups of patients based on their relative risk and thus embracing a kind of ‘stratified medicine’. The baseline risk of PONV in an individual having a specific surgery and anaesthetic may be assessed using a validated risk score that is based on the (weighted) sum of independent predictors. Such prognostic models have been used to guide preventive therapy. Yet, there are conflicting results on the use of PONV risk scores to significantly reduce the institutional rates of PONV. After an enthusiastic update—based on established guideline recommendations—of totally risk-adopted approaches to prevent PONV with zero prevention in supposed low-risk patients, there has been an intense debate and discussion whether these approaches actually work in a busy clinical environment. – 22 Up to now, for all of us who are not convinced about the overall positive net benefit of the antiemetic interventions mentioned earlier, such an approach would be the best way to achieve as much benefit as possible with the least potential for adverse effects; providing that the scores do work. A third approach would be to treat PONV if symptoms actually arise. Clearly, this would lead to an increased PONV incidence, but if symptoms are detected early enough and then an aggressive treatment by means of multimodal drugadministration can be instituted without delay, at least the best net benefit (in terms of numbers-needed-to-treat) would be generated. However, the findings of a recent clinical trial showing that emetic symptoms, and particularly nausea, are frequently missed in a busy clinical scenario render such an approach invalid. This observational study shows that only 42% and 29% of PONV episodes were actually detected by the regular staff in the post-anaesthesia care unit (PACU) and on the ward, respectively. Therefore, such a concept would clearly demand a very alert environment in which patients are adequately informed and encouraged to report any signs of nausea, and moreover, a rapid and aggressive treatment would need to be ensured. These two prerequisites prohibit such an approach based on aggressive treatment, in particular in children, where a valid assessment of emetic symptoms, especially with respect to the feeling of nausea, is limited. Further, such an approach is incompatible with busy environments where nursing staff and physicians are short of time and a close monitoring of PONV symptoms and an appropriate response (instant and effective treatment) cannot be ensured for at least 24 h after anaesthesia. What remains the best choice at the end of the day is highly dependent on the environment and the clinical scenario, and especially the guideline compliance of the suggested BJA Editorials