Hemmingsen C, Nielsen J E
Department of Anaesthesia, University Hospital, Copenhagen, Denmark.
Acta Anaesthesiol Scand. 1991 Nov;35(8):755-7. doi: 10.1111/j.1399-6576.1991.tb03385.x.
Spinal block causes paralysis of preganglionic sympathetic fibres, while ketamine induces activation of the sympathetic nervous system. Hypotension is a frequent complication during spinal anaesthesia and is associated with an increased risk of postoperative mortality. The aim of our study was to compare circulatory changes in patients who received either fentanyl or ketamine during spinal anaesthesia. Thirty patients (ASA I-III) scheduled to undergo spinal anaesthesia for osteosynthesis of hip fractures were allocated to receive either ketamine or fentanyl intravenously during the procedure. Immediately before anaesthesia, 7 ml/kg BW of an isotonic NaCl solution was administered i.v. Patients received either fentanyl 1.5 mg/kg BW i.v. before anaesthesia, or ketamine 0.7 mg/kg BW i.v. before anaesthesia, and 0.35 mg/kg BW 15 and 30 min after the first dose. No prophylactic vasopressor was used. During the first 40 min of anaesthesia a fluid load of 14 ml/kg BW was given i.v. If the mean arterial pressure (MAP) fell more than 20%, the infusion rate was increased. If the reduction in MAP exceeded 33% or if the systolic pressure decreased to less than 80 mmHg, patients were registered as haemodynamically unstable. In both groups the spinal anaesthesia caused a reduction in MAP. The MAP was lower in the fentanyl group than in the ketamine group at all times. In the fentanyl group six subjects developed a haemodynamically unstable condition, while only one subject in the ketamine group was registered as such (P less than 0.05). There was no significant change in heart rate in either group. We conclude that during spinal anaesthesia patients can in part be kept haemodynamically stable by intravenous administration of ketamine.
脊髓阻滞会导致节前交感神经纤维麻痹，而氯胺酮会诱导交感神经系统激活。低血压是脊髓麻醉期间常见的并发症，且与术后死亡率增加相关。我们研究的目的是比较在脊髓麻醉期间接受芬太尼或氯胺酮的患者的循环变化。30例计划接受脊髓麻醉以进行髋部骨折内固定术的患者（ASA I - III级）被分配在手术过程中静脉注射氯胺酮或芬太尼。麻醉前即刻，静脉注射7 ml/kg体重的等渗氯化钠溶液。患者在麻醉前静脉注射芬太尼1.5 mg/kg体重，或在麻醉前静脉注射氯胺酮0.7 mg/kg体重，并在首剂后15分钟和30分钟分别静脉注射0.35 mg/kg体重。未使用预防性血管升压药。在麻醉的前40分钟内，静脉给予14 ml/kg体重的液体负荷。如果平均动脉压（MAP）下降超过20%，则增加输液速度。如果MAP降低超过33%或收缩压降至低于80 mmHg，则将患者记录为血流动力学不稳定。两组中脊髓麻醉均导致MAP降低。芬太尼组的MAP在所有时间均低于氯胺酮组。芬太尼组有6名受试者出现血流动力学不稳定状态，而氯胺酮组只有1名受试者被记录为血流动力学不稳定（P小于0.05）。两组的心率均无显著变化。我们得出结论，在脊髓麻醉期间，通过静脉注射氯胺酮可部分维持患者的血流动力学稳定。
