Matthews J M, Wheeler G D, Burnham R S, Malone L A, Steadward R D
Rick Hansen Centre, University of Alberta, Edmonton, Canada.
Spinal Cord. 1997 Oct;35(10):647-51. doi: 10.1038/sj.sc.3100488.
Recently, increases in blood pressure (BP) and concomitant bradycardia, suggestive of autonomic dysreflexia (AD), have been documented during functional electrical stimulation (FES) in individuals with a high spinal cord injury (SCI). If uncontrolled, this response could preclude the safe use of FES among such individuals. FES induced pain is partly related to stimulation of skin nociceptors. Therefore, measures to reduce skin sensitivity may reduce the risk of AD during FES. The purpose of this study was to determine if topical anaesthetic applied over the site of electrical stimulation could minimize the AD cardiovascular and hormonal responses to FES in individuals with SCI above the T6 level. Seven subjects with a SCI above T6 received FES to the quadriceps muscle of each leg under two conditions on two different testing days. The two treatment conditions, topical anaesthetic and placebo creams, were double blinded and randomized. The cream was administered to an area the size of the electrode (10 x 10 cm) 1 h prior to stimulation. Stimulation began at 0 mAmps and increased by 16 mAmps every 2 min until an intensity of 160 mAmps was achieved. HR and BP were measured at each stimulation intensity level. Catecholamines were analyzed three times during the stimulation protocol (pre, mid and post stimulation intensities). At the end of the stimulation protocol, FES induced isometric quadriceps contraction force at 160 mAmps intensity was measured using a hand held dynamometer. As FES stimulation intensity increased, significant rises in systolic and diastolic BP were seen, with a concomitant progressive drop in HR. The AD response to stimulation was not significantly different between the topical anaesthetic and placebo conditions. Serum catecholamine (epinephrine and norepinephrine) levels tended to rise with increasing FES intensity levels but did not reach statistical significance. The two treatment conditions did not significantly affect serum catecholamine levels or FES-induced quadriceps contraction force. In summary, FES application to the quadriceps muscle in high level SCI subjects resulted in significant increases in BP, decreases in HR (AD-like response), a trend towards elevations in catecholamine levels, and no difference in quadriceps muscular strength. However, these responses were unaffected by the use of topical anaesthetic cream on the skin at the stimulation site. This suggests that other mechanisms than skin nociception are operative in FES-induced AD.
最近，有文献记载，在对高位脊髓损伤（SCI）患者进行功能性电刺激（FES）期间，出现了血压（BP）升高并伴有心动过缓的情况，提示存在自主神经反射异常（AD）。如果这种反应得不到控制，可能会妨碍在这类患者中安全使用FES。FES诱发的疼痛部分与皮肤伤害感受器的刺激有关。因此，降低皮肤敏感性的措施可能会降低FES期间发生AD的风险。本研究的目的是确定在T6水平以上的SCI患者中，在电刺激部位涂抹局部麻醉剂是否能使AD对FES的心血管和激素反应降至最低。7名T6以上SCI患者在两个不同的测试日，在两种条件下接受对每条腿股四头肌的FES。两种治疗条件，即局部麻醉剂和安慰剂乳膏，采用双盲随机法。在刺激前1小时，将乳膏涂抹在电极大小的区域（10×10厘米）。刺激从0毫安开始，每2分钟增加16毫安，直至达到160毫安的强度。在每个刺激强度水平测量心率（HR）和血压。在刺激方案期间（刺激强度前、中、后）对儿茶酚胺进行三次分析。在刺激方案结束时，使用手持测力计测量在160毫安强度下FES诱发的股四头肌等长收缩力。随着FES刺激强度的增加，收缩压和舒张压显著升高，同时心率逐渐下降。局部麻醉剂和安慰剂条件下对刺激的AD反应没有显著差异。血清儿茶酚胺（肾上腺素和去甲肾上腺素）水平倾向于随着FES强度水平的增加而升高，但未达到统计学显著性。两种治疗条件对血清儿茶酚胺水平或FES诱发的股四头肌收缩力没有显著影响。总之，对高位SCI患者的股四头肌施加FES会导致血压显著升高、心率降低（类似AD的反应）、儿茶酚胺水平有升高趋势，且股四头肌肌力无差异。然而，这些反应不受在刺激部位皮肤使用局部麻醉剂乳膏的影响。这表明在FES诱发的AD中，除了皮肤伤害感受外，还有其他机制在起作用。
