Clinical Study of Failure in Continuous Spinal Anesthesia with Bupivacaine

Abstract

背景：連續性脊椎麻醉已被認為較單一注射劑量的脊椎麻醉具有注射劑量可調節性， 血液動力穩定性的優點。但對麻醉醫師極言，脊椎麻醉的失敗並不少見。在此，我們 報告在處理連續性脊椎麻醉失敗時的經驗及討論造成失敗的可能原因。方法：採回溯 性研究236位（皆大於65歲，ASA III）接受泌尿外科，骨科手術的病例。使用0.2% Bupivacaine做連續性脊椎麻醉，在20 mg Bupivacaine注射後30分鐘，若在皮節區T 10有針刺痛感(pin prick test)即認定為連續性脊椎麻醉失敗。隨即改以5 mL 1% Lidocaine注射。記錄Lidocaine的失敗率，感覺和運動阻斷的情形，以及失敗的病例 改以1% Lidocaine救援的成功率及所需要Lidocaine的平均劑量。結果：236位病例中 有11個病例被認定為Bupivacaine連續性脊椎麻醉失敗，失敗率為4.7%。在隨即改以5 mL 1% Lidocaine注射後，5分鐘內，有9個病例馬上產生溫度，感覺和運動阻斷的情 形。有2個病例，需要注射較多劑量的Lidocaine才可以達到相同的阻斷的情形。 Lidocaine救援成功率100%，所需要Lidocaine的平均劑量52±4.5mg。結論：在區域 性麻醉時失敗的原因包括技術不良、病人因素、藥品因素。本研究發現，造成連續性 脊椎麻醉失敗的原因中，局部麻醉藥本身的問題可能扮演著主要的角色。 Background: Continuous spinal anesthesia (CSA) has been considered to be better in temporal and dose flexibility, as well as hemodynamic stability than sigle dose spinal anesthesia. However, the failure of spinal anesthesia is not a rare experience for anesthesiologists. Here we present our experience in solving the problem and discuss the possible causes for the failure. Methods: 236 cases were studied retrospectively from January to December in 1996. All were over 65 years old, ASA III, scheduled for transurethral procedures or orthopedic operation. CSA was performed with 0 .2% bupivacaine. Failed CSA was confirmed by positive pin-prick test at T 10 dermatome(umbilicus) 30 minutes after 20 mg bupivacaine was injected. For failed cases, 5 mL 1% lidocaine was injected intrathecally for rescue. The failure rate, sensory and motor blockade, success rate by changing to lidocaine and its dosage were recorded. Results: Eleven of 236 cases (4.7 %) were considered spinal failure since the initial 20 mg bupivacaive could not provide adequate T10 anesthesia in 30 minutes. Addition of 5 mL 1% lidocaine produced a profound sensory and motor blockade in 9 cases, while further lidocaine injection was required in two cases. The success rate by rescuing lidocaine was 100% with an average lidocaine consumption by 52±4.5mg. Discussion: Factors contributed to failure spinal anesthesia including failure of technique, errors of judgment, maldistribution and failure of local anesthetic itself. However, we thought that change of pH value of local anesthetic in CSF may play a great part in these failed CSAs. Despite the reasons for failure, we demonstrate that failure of continuous spinal anesthesia by 0.2% bupivacaine can be readily resolved by 1% lidocaine. <<本系統設定每次下載資料最多不超過5000筆>>