Apfel Christian C, Stoecklein Katrin, Lipfert Peter
Department of Anesthesiology and Perioperative Medicine, and Outcomes Research Institute, University of Louisville, 501 E Broadway, Suite 210, Louisville, KY 40202, USA.
Best Pract Res Clin Anaesthesiol. 2005 Sep;19(3):485-500. doi: 10.1016/j.bpa.2005.03.001.
Even nowadays every third or fourth patient suffers from postoperative nausea and vomiting (PONV) after general anaesthesia with volatile anaesthetics. There is now strong evidence that volatile anaesthetics are emetogenic and that there are no meaningful differences between halothane, enflurane, isoflurane, sevoflurane, and desflurane in this respect. However, when propofol is substituted for volatile anaesthetics the risk for PONV is reduced by only about one fifth, indicating that there are other even more important causes for PONV following general anaesthesia. A main causative factor might be the use of perioperative opioids, but their impact--relative to other factors including volatile anaesthetics--has never been quantified. Patient-specific risk factors have also been shown to be clinically relevant; they are therefore included in the calculation of simplified risk scores that allow prediction of a patient's risk independent of the type of surgery. Although controversial, the well-known different incidences following certain types of surgery are most likely caused by patient-specific and anaesthesia-related risk factors. There is a common consensus that prophylaxis with anti-emetic strategies is rarely justified when the risk of PONV is low, while it is warranted in case of imminent medical risk associated with vomiting or in a patient with a high risk for PONV. A recently published large multicentre trial of factorial design, IMPACT, has demonstrated that various anti-emetic strategies are associated with a very similar and constant relative reduction rate of about 25-30% and that the main predictor for the efficacy of prophylaxis is the patient's risk for PONV. Interestingly, all anti-emetics (dexamethasone, droperidol and ondansetron) work independently, so that their combined benefit can be derived directly from the single effects. The effectiveness of the anti-emetics was also independent of a variety of risk factors, including volatile anaesthetics. This means that any anti-emetic prophylaxis for PONV induced by volatile anaesthetics is equally effective. Of course, the most logical approach for prevention would be the omission of volatile anaesthetics and nitrous oxide using a total intravenous anaesthesia with propofol. However, since volatile anaesthetics are probably not the most important risk factors, it might be even better--if appropriate--to avoid general anaesthesia by using a regional, opioid-free anaesthesia if PONV is a serious problem.
即使在当今，每三到四位接受挥发性麻醉剂全身麻醉的患者中就有一位会出现术后恶心呕吐（PONV）。现在有强有力的证据表明，挥发性麻醉剂会引发呕吐，并且在这方面氟烷、恩氟烷、异氟烷、七氟烷和地氟烷之间没有显著差异。然而，当用丙泊酚替代挥发性麻醉剂时，PONV的风险仅降低约五分之一，这表明全身麻醉后PONV还有其他更重要的原因。一个主要的致病因素可能是围手术期使用阿片类药物，但其影响——相对于包括挥发性麻醉剂在内的其他因素——从未被量化。患者特异性风险因素在临床上也被证明是相关的；因此，它们被纳入简化风险评分的计算中，该评分可以独立于手术类型预测患者的风险。尽管存在争议，但某些类型手术后众所周知的不同发生率很可能是由患者特异性和麻醉相关风险因素引起的。人们普遍认为，当PONV风险较低时，很少有理由采用抗呕吐策略进行预防，而当存在与呕吐相关的紧迫医疗风险或患者PONV风险较高时，则有必要进行预防。最近发表的一项采用析因设计的大型多中心试验IMPACT表明，各种抗呕吐策略的相对降低率非常相似且恒定，约为25% - 30%，并且预防效果的主要预测因素是患者的PONV风险。有趣的是，所有抗呕吐药物（地塞米松、氟哌利多和昂丹司琼）都独立起作用，因此它们的联合益处可以直接从单一效果中推导出来。抗呕吐药物的有效性也独立于多种风险因素，包括挥发性麻醉剂。这意味着任何针对挥发性麻醉剂引起的PONV的抗呕吐预防措施都同样有效。当然，最合理的预防方法是使用丙泊酚进行全静脉麻醉，避免使用挥发性麻醉剂和氧化亚氮。然而，由于挥发性麻醉剂可能不是最重要的风险因素，如果PONV是一个严重问题，在合适的情况下，通过使用区域无阿片类麻醉避免全身麻醉可能会更好。
