Department of Anesthesiology, Intensive Care and Pain Medicine, University Hospital Münster, Münster, Germany.
Curr Opin Anaesthesiol. 2019 Jun;32(3):263-267. doi: 10.1097/ACO.0000000000000721.
As the application of a test dose after epidural catheter insertion in obstetrics has recurrently been associated with serious adverse events affecting both maternal and foetal outcomes, the question whether to test or not remains a controversial issue.
Present guidelines do not provide clear recommendations in this regard and several recent surveys indicate a heterogeneity in clinical routine.
Physiological alterations during pregnancy and labour restrict the use and also the validity of traditional test agents. Epinephrine is not appropriate to detect a vascular insertion in labour and the application of a local anaesthetic test dose may lead to dose-dependent fatal consequences should the catheter be intrathecal, due to an increased sensitivity in parturients. Given the current practice of opioid-amended-low-concentration epidurals, the waiving of a test dose results at worst in a failed epidural, a stark contrast to the potentially severe to fatal complications of a 'traditional' test dose. Hence, an originally preventive measure providing potentially more harm than the consequences of the situation aimed to prevent, should not be recommended. A simple fractionated administration of the initial analgesic dose seems reasonable though.
由于硬膜外导管插入后应用试验剂量反复与影响母婴结局的严重不良事件相关，是否进行试验仍存在争议。
目前的指南在这方面没有提供明确的建议，最近的几项调查表明临床常规存在异质性。
妊娠和分娩期间的生理变化限制了传统试验剂的使用和有效性。肾上腺素不适合检测分娩时的血管插入，局部麻醉试验剂量的应用可能导致导管进入蛛网膜下腔时出现剂量依赖性致命后果，因为产妇的敏感性增加。鉴于目前阿片类药物复合低浓度硬膜外麻醉的应用，不使用试验剂量最坏的结果是硬膜外麻醉失败，与“传统”试验剂量可能导致的严重至致命并发症形成鲜明对比。因此，不应该推荐原本作为预防措施的方案，因为该方案可能弊大于利。不过，最初的镇痛剂量分次给予似乎是合理的。
