Whitwam J G
Department of Anaesthesia, Royal Postgraduate Medical School, London, UK.
Eur J Anaesthesiol Suppl. 1995 Nov;12:25-34.
The term co-induction of anaesthesia has been applied to the use of two or more drugs to induce anaesthesia. The term was introduced in 1986 to describe the unplanned induction of anaesthesia by non-anaesthetically trained personnel practising sedation. A new benzodiazepine was combined with opioids, with synergistic effects, causing unplanned anaesthesia in an unsuitable environment leading to several fatalities. Currently, planned co-induction of anaesthesia is practised by anaesthetists exploiting drug interactions, particularly synergism, principally between midazolam, fentanyl, sufentanil and alfentanil, and propofol. It can produce an improvement in all phases of anaesthesia, including induction, maintenance and recovery. There are advantages in combining midazolam with propofol, thereby reducing the risk of awareness and also the dose of propofol and hence its side-effects and cost. Propofol is the principal intravenous induction agent for day-case anaesthesia. The pre-administration of 0.03 mg kg-1 of midazolam (approximately 2 mg in normal healthy adults) is now being practised widely. Current papers suggest that 2 mg of midazolam administered to an average, otherwise healthy, adult does not compromise recovery, whereas an increase to 5 mg may be expected to delay the possibility of final discharge of such patients by about 20 min. The use of midazolam and propofol with or without either fentanyl or alfentanil is probably the principal technique for the induction of day-case anaesthesia at the present time. A major advantage is that by reducing the dose of propofol there is less chance of the severe bradycardia that is sometimes associated with the combined use of propofol and opioids, although this can be prevented by vagolytic agents. However, the use of opioids increases the incidence of post-operative nausea and vomiting. Another important drug is ketamine, the effects of which are often additive with other drugs. The combination of ketamine and midazolam is an important technique, particularly in the management of critically ill patients. The alpha 2-agonists, e.g. clonidine and dexmedetomidine, may also have a role in this context in the future. This paper presents the current approach to the co-induction of anaesthesia, particularly in relation to the reduced risk of awareness when using midazolam, and the health economics in relation to the potential reduction in the dose and hence cost of propofol.
联合诱导麻醉这一术语已应用于使用两种或更多药物来诱导麻醉的情况。该术语于1986年被引入，用于描述未接受麻醉培训的人员在实施镇静时意外诱导麻醉的情况。一种新的苯二氮䓬类药物与阿片类药物联合使用，产生协同作用，在不合适的环境中导致意外麻醉，造成了几起死亡事件。目前，麻醉医生利用药物相互作用，特别是协同作用，主要是咪达唑仑、芬太尼、舒芬太尼和阿芬太尼与丙泊酚之间的协同作用，进行有计划的联合诱导麻醉。它可以在麻醉的各个阶段产生改善，包括诱导、维持和苏醒。将咪达唑仑与丙泊酚联合使用有诸多优点，从而降低知晓风险，同时减少丙泊酚的剂量，进而降低其副作用和成本。丙泊酚是日间手术麻醉的主要静脉诱导药物。目前广泛采用预先给予0.03 mg/kg的咪达唑仑（正常健康成年人约为2 mg）。当前的文献表明，给予平均体重的健康成年患者2 mg咪达唑仑不会影响苏醒，而增加到5 mg可能会使这类患者最终出院的时间延迟约20分钟。目前，使用咪达唑仑和丙泊酚，无论是否联合使用芬太尼或阿芬太尼，可能是日间手术麻醉诱导的主要技术。一个主要优点是，通过减少丙泊酚的剂量，严重心动过缓的发生几率降低，严重心动过缓有时与丙泊酚和阿片类药物联合使用有关，不过这可以通过抗迷走神经药物预防。然而，使用阿片类药物会增加术后恶心和呕吐的发生率。另一种重要药物是氯胺酮，其作用通常与其他药物相加。氯胺酮与咪达唑仑的联合是一种重要技术，尤其在危重症患者的管理中。α2激动剂，如可乐定和右美托咪定，在未来这方面可能也会发挥作用。本文介绍了联合诱导麻醉的当前方法，特别是在使用咪达唑仑时降低知晓风险方面，以及在潜在降低丙泊酚剂量从而降低成本方面的卫生经济学情况。
