Tetzlaff J E, O'Hara J, Yoon H J, Schubert A G
Department of General Anesthesiology, Cleveland Clinic Foundation, OH 44195, USA.
J Clin Anesth. 1998 Mar;10(2):133-6. doi: 10.1016/s0952-8180(97)00253-5.
To evaluate the onset of spinal anesthesia with power spectral heart rate analysis to determine the influence of the block on the autonomic nervous system.
Prospective, clinical evaluation.
Tertiary-care teaching hospital.
27 ASA physical status I and II patients scheduled for lower extremity orthopedic surgery and free of major cardiac disease or cardiac drugs with direct influence of heart rate (HR) or blood pressure (BP).
Prior to anesthesia, a baseline power spectral heart rate reading was taken in the supine position. Spinal anesthesia was established in the sitting position with 15 mg of bupivacaine and 0.2 mg epinephrine introduced at the L3-L4 interspace with a 22-gauge Quincke needle. The patient was returned supine, and power spectral heart rate data were again collected at 5-minute intervals throughout the procedure. Level of the spinal block was checked at 5-minute intervals until 30 minutes and considered complete when two consecutive readings were unchanged.
Heart rate and BP were recorded at baseline and at five-minute intervals after injection. Power spectral heart rate data included low-frequency activity (LFa), high-frequency activity (HFa), and the ratio (LFa/HFa). Spinal level achieved was recorded by thoracic dermatome at complete onset. Heart rate and BP remained within 20% of control in all cases. Complete onset of the spinal block was present by 30 minutes in all cases. The average level of spinal anesthesia was T8. Compared with baseline, LFa activity decreased, HFa activity remained unchanged, and the ratio was decreased. During endoprosthesis insertion, 9 of 14 total hip patients had a transient ten-fold increase in LFa activity, without HFa change, and a corresponding increase in the ratio.
Power spectral heart rate analysis during low thoracic bupivacaine spinal anesthesia is compatible with decreased sympathetic activity during stable hemodynamic intervals. Insertion of hip endoprosthesis resulted in a dramatic, transient increase in sympathetic activity, indicating that sympathetic activation was still possible despite the presence of surgical anesthesia from the subarachnoid block.
通过功率谱心率分析评估脊髓麻醉的起效情况，以确定该阻滞对自主神经系统的影响。
前瞻性临床评估。
三级护理教学医院。
27例美国麻醉医师协会（ASA）身体状况为I级和II级的患者，计划进行下肢骨科手术，且无重大心脏疾病或使用对心率（HR）或血压（BP）有直接影响的心脏药物。
麻醉前，在仰卧位获取基线功率谱心率读数。患者取坐位，于L3-L4间隙用22号昆克针注入15mg布比卡因和0.2mg肾上腺素建立脊髓麻醉。患者恢复仰卧位，在整个手术过程中每隔5分钟再次收集功率谱心率数据。每隔5分钟检查脊髓阻滞平面，直至30分钟，当连续两次读数不变时视为阻滞完成。
记录基线及注射后每隔5分钟的心率和血压。功率谱心率数据包括低频活动（LFa）、高频活动（HFa）及比值（LFa/HFa）。脊髓阻滞完全起效时，记录达到的脊髓平面（以胸段皮节表示）。所有病例的心率和血压均保持在对照值的20%以内。所有病例在30分钟时脊髓阻滞均完全起效。脊髓麻醉的平均平面为T8。与基线相比，LFa活动降低，HFa活动不变，比值降低。在全髋关节置换术中，14例全髋关节患者中有9例在植入假体时LFa活动瞬间增加了10倍，HFa无变化，且比值相应增加。
低位胸段布比卡因脊髓麻醉期间的功率谱心率分析与稳定血流动力学期间交感神经活动降低相符。髋关节假体植入导致交感神经活动急剧、短暂增加，表明尽管存在蛛网膜下腔阻滞的手术麻醉，但交感神经仍可能被激活。
