Urmey W F, Gloeggler P J
Department of Anesthesiology, Hospital for Special Surgery, Cornell University Medical College, New York, New York 10021.
Reg Anesth. 1993 Jul-Aug;18(4):244-9.
During interscalene block, ipsilateral hemidiaphragmatic paresis occurred in all patients who received > 34 ml of local anesthetic in the authors' previous studies. This study was done to determine whether diaphragmatic function could be spared by a smaller local anesthetic volume.
Twenty patients were randomly assigned to receive either a 45 ml or 20 ml interscalene brachial plexus block. For all blocks, 1.5% mepivacaine with added epinephrine and bicarbonate was used. Baseline serial measurements and those over a 30-minute test period before surgery were analyzed for significant differences between groups in onset or final change in any of the following measured variables: cephalad dermatomal extent of sensory anesthesia, clinically assessed upper extremity motor function, ipsilateral hemidiaphragmatic excursion during maximal sniff (inspiratory), and pulmonary function.
There were no clinically significant differences between groups in any of the measured variables. Large reductions in routine pulmonary function tests were measured in all patients in both groups at 2 minutes after injection. At 30 minutes, baseline forced vital capacity (FVC) had diminished by 40.9 +/- 11.7% in the 45 ml group and 32.0 +/- 8.9% in the 20 ml group. One patient with pre-existing chronic obstructive pulmonary disease had a decrease in FVC from 1.83 l to 0.59 l, a 68% decrement from the baseline measurement, both measured in the supine position.
Reducing the volume of local anesthetic to 20 ml did not prevent the 100% incidence of diaphragmatic paresis or significantly lessen the compromise in pulmonary function that had been reported to occur during interscalene brachial plexus anesthesia.
在前瞻性研究中，接受超过34ml局部麻醉剂的患者在肌间沟阻滞期间均出现同侧半膈肌麻痹。本研究旨在确定较小剂量的局部麻醉剂是否可以避免膈肌功能受影响。
20例患者随机接受45ml或20ml肌间沟臂丛神经阻滞。所有阻滞均使用添加肾上腺素和碳酸氢盐的1.5%甲哌卡因。分析基线系列测量值以及术前30分钟测试期内的测量值，比较两组在以下任何测量变量的起效时间或最终变化方面的显著差异：感觉麻醉的头侧皮节范围、临床评估的上肢运动功能、最大吸气时同侧半膈肌偏移以及肺功能。
两组在任何测量变量上均无临床显著差异。两组所有患者在注射后2分钟时常规肺功能测试均大幅下降。30分钟时，45ml组的基线用力肺活量（FVC）下降了40.9±11.7%，20ml组下降了32.0±8.9%。一名患有慢性阻塞性肺疾病的患者，仰卧位测量时FVC从1.83L降至0.59L，较基线测量值下降了68%。
将局部麻醉剂体积减少至20ml并不能防止膈肌麻痹的100%发生率，也不能显著减轻肌间沟臂丛神经麻醉期间据报道出现的肺功能损害。
