低劑量的嗎啡及bupivacaine作為硬脊膜外止痛劑的全身性毒性的病例報告

Systemic Toxicity Following Epidural Analgesia with Small Volume Morphine/Bupivacaine- A Case Report

對於開刀術後的疼痛控制，合併嗎啡類的藥物及局部麻醉劑的使用，作為硬脊膜外的止痛劑，不但是有效且受歡迎的方式，也可以減少兩種藥物的劑量及副作用。我們報告一例66歲160公分高58公斤重的女性，無顯著的疾病史，因退化性關節炎，接受左側的人工膝關節置換術，使用的是硬脊膜外麻醉，導管的置放過程順利（腰椎第1,2節間，向上放置4公分，麻醉有效範圍至胸椎第十節），整個手術於3個小時內結束，術後並留下硬脊膜外導管作為術後止痛，使用l.Omg的morphine和5ml0.25克的bupivacaine每12小時給予一劑，前兩次給藥順利，然而，當要給予第三次劑量時，患者發生了躁動不安，嗜睡，昏迷及心律不整，但沒有明顯的呼吸抑制，基於症狀及發生的時間，疑似局部麻醉劑經血管急速吸收的可能性比較高，經緊急處理後，患者於30分鐘內恢復，並且觀察4天後仍沒有任何的神經學後遺症發生，硬脊膜外導管留置後，會因為患者活動或姿勢改變而移動位子，甚至進入血管中，儘管嚴重的硬脊膜外止痛劑中毒曾經被報告遇，但在低劑量注射多次後才發生並不常見，因此建議仍然需要小心的監視生命徵象和給予緊急的處置。

Epidural analgesia combined with opioid and local anesthetics for postoperative pain control is an excellent and popular method that reduces the dosage and risks of side effects from both drugs. In our study, a 66-year-old, 160 cm 58 kg woman with an unremarkable past medical history, underwent L't total knee replacement surgery with epidural anesthesia. The epidural catheter , placement procedure went smoothly (L spine 1, 2 intervertebral space up to 4cm in the space, level up to Tlo} and the operation was done within 3 hours. After that, l.Omg morphine and 5ml 0.25% bupivacaine were administered twice through the epidural catheter, once every 12 hours, for postoperative analgesia. However, when a third dose was given, the patient suffered from irritable, lethargy and cardiac arrhythmia without obvious respiratory suppression. Based on the symptoms and onset time, inadvertent fast intravascular uptake was the likely etiology. Although the patient recovered in 30 minutes and remained without any neurological sequelae 4 days later. Despite the severe toxicity after epidural analgesia was reported before it's rare after multiple small volumes administered. Careful monitoring of vital signs and emergency treatment were still required.