Hawksworth C, Serpell M
University Department of Anaesthesia, Western Infirmary, Glasgow, Scotland.
Reg Anesth Pain Med. 1998 May-Jun;23(3):283-8. doi: 10.1016/s1098-7339(98)90056-6.
Intrathecal anesthesia is the method of choice for transurethral prostate resection in the United Kingdom, despite its associated hypotension. Intrathecal ketamine with epinephrine has been used for lower limb surgery with minimal cardiovascular disturbance. Because cardiovascular stability might be advantageous in this group of elderly patients, we undertook this study to determine if intrathecal ketamine was a suitable intrathecal anesthetic agent for transurethral prostate surgery. Because of the high incidence of side effects and inadequate analgesia, the study was terminated after only ten patients had been recruited.
Ten ASA I to III males were studied. Spinal anesthesia was performed with a 25-gauge Whitacre needle at the L2-L3 or L3-L4 space. The dose of ketamine was determined by a sequential allocation technique after initial empirical doses of 0.5 and 0.75 mg/kg. Sensory and motor block were monitored using pinprick and modified Bromage score, respectively. If spinal anesthesia was inadequate at any time, a general anesthetic was administered.
At doses higher than 0.7 mg/kg, intrathecal ketamine produced both motor and sensory block. The onset of motor block was within 2-3 minutes, peaked in 5-10 minutes, and lasted 30-60 minutes. Sensory block took 5-20 minutes to reach its maximal height. Maximum sensory block height varied from L1 to T7. Despite adequate block to pinprick, half the patients sensed the diathermy and were given a general anesthetic. The incidence of severe psychotomimetic side effects was 30%.
Intrathecal ketamine at doses of 0.7-0.95 mg/kg produces sensory and motor block. The frequency of psychomimetic disturbance, inadequate analgesia, and short duration of action preclude its use as a sole anesthetic agent.
在英国，尽管蛛网膜下腔麻醉会导致低血压，但它仍是经尿道前列腺切除术的首选麻醉方法。蛛网膜下腔注射氯胺酮联合肾上腺素已用于下肢手术，且对心血管系统的干扰极小。鉴于心血管稳定性对这类老年患者可能有益，我们开展了这项研究，以确定蛛网膜下腔注射氯胺酮是否是经尿道前列腺手术合适的蛛网膜下腔麻醉剂。由于副作用发生率高且镇痛效果不佳，仅招募了10例患者后该研究就终止了。
对10例美国麻醉医师协会（ASA）分级为I至III级的男性患者进行研究。使用25G的惠特克针在L2-L3或L3-L4间隙进行脊髓麻醉。在初始经验剂量0.5和0.75mg/kg后，通过序贯分配技术确定氯胺酮的剂量。分别使用针刺和改良布罗玛格评分来监测感觉和运动阻滞情况。如果在任何时候脊髓麻醉效果不佳，则给予全身麻醉。
当剂量高于0.7mg/kg时，蛛网膜下腔注射氯胺酮会产生运动和感觉阻滞。运动阻滞在2-3分钟内开始，5-10分钟达到峰值，持续30-60分钟。感觉阻滞需要5-20分钟达到最大高度。最大感觉阻滞平面从L1到T7不等。尽管对针刺有足够的阻滞，但仍有一半患者感觉到了电切，并接受了全身麻醉。严重的拟精神副作用发生率为30%。
剂量为0.7-0.95mg/kg的蛛网膜下腔注射氯胺酮会产生感觉和运动阻滞。拟精神障碍的发生频率、镇痛效果不佳以及作用时间短使其不能作为单一麻醉剂使用。
