Murali Krishna T, Panda N B, Batra Y K, Rajeev S
Postgraduate Institute of Medical Education and Research, Department of Anaesthesia and Intensive Care, Chandigarh, India.
Eur J Anaesthesiol. 2008 Apr;25(4):299-306. doi: 10.1017/S0265021507002645. Epub 2007 Sep 25.
Intrathecal ketamine produces a short period of analgesia with stable haemodynamics. Midazolam with bupivacaine prolongs the duration of analgesia when administered intrathecally but does not prevent hypotension. The objective of this study was to assess the effect of a combination of intrathecal bupivacaine, ketamine and midazolam on the duration of analgesia and haemodynamic parameters.
A prospective, randomized, double-blind study was carried out in 60 ASA I and II patients undergoing lower limb surgery under spinal anaesthesia. Patients were divided into three groups of 20 each. Patients in all the three groups received 3 mL of hyperbaric bupivacaine (0.5%) intrathecally. In addition, patients in Groups II and III received intrathecal ketamine (0.1 mg kg-1) and the same dose of ketamine along with midazolam (0.02 mg kg-1), respectively. All patients were evaluated for block characteristics, duration of pain-free period, total rescue analgesic requirement in the 24-h postoperative period, total dose of mephenteramine to treat hypotension and any central or neurological complication.
No patients in Group II required mephenteramine while 40% of patients in Group I and 10% in Group III required mephenteramine to maintain blood pressure after spinal anaesthesia. The mean +/- standard deviation duration of pain-free period was 331.5 +/- 89.9, 369.7 +/- 124.2 and 730.5 +/- 81.5 min in Group I, II and III, respectively. The pain-free interval was significantly greater in Group III compared to Groups I and II (P < 0.001). No patient had any complications.
A low dose of midazolam and ketamine with bupivacaine intrathecally results in prolonged analgesia and less haemodynamic fluctuations. However, the safety of this combination needs to be proved before its use in clinical practice.
鞘内注射氯胺酮可产生短期镇痛作用，且血流动力学稳定。鞘内注射咪达唑仑与布比卡因可延长镇痛时间，但不能预防低血压。本研究的目的是评估鞘内注射布比卡因、氯胺酮和咪达唑仑联合应用对镇痛时间和血流动力学参数的影响。
对60例接受脊髓麻醉下行下肢手术的美国麻醉医师协会（ASA）I级和II级患者进行了一项前瞻性、随机、双盲研究。患者被分为三组，每组20例。所有三组患者均鞘内注射3 mL重比重布比卡因（0.5%）。此外，第二组和第三组患者分别鞘内注射氯胺酮（0.1 mg/kg）以及相同剂量的氯胺酮与咪达唑仑（0.02 mg/kg）。对所有患者评估阻滞特征、无痛期持续时间、术后24小时内总的补救镇痛需求、治疗低血压所需去氧肾上腺素的总剂量以及任何中枢或神经并发症。
第二组无患者需要去氧肾上腺素，而第一组40%的患者和第三组10%的患者在脊髓麻醉后需要去氧肾上腺素来维持血压。第一组、第二组和第三组的平均±标准差无痛期持续时间分别为331.5±89.9、369.7±124.2和730.5±81.5分钟。与第一组和第二组相比，第三组的无痛间隔明显更长（P<0.001）。无患者出现任何并发症。
鞘内注射低剂量咪达唑仑、氯胺酮与布比卡因可延长镇痛时间并减少血流动力学波动。然而，在临床实践中使用这种联合用药之前，其安全性需要得到证实。
