Oberlander T F, Berde C B, Lam K H, Rappaport L A, Saul J P
Department of Cardiology, Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
Anesth Analg. 1995 Jan;80(1):20-7. doi: 10.1097/00000539-199501000-00005.
Unlike adults, neonates tolerate high thoracic spinal anesthesia with minimal changes in heart rate (HR) and arterial blood pressure. To examine the potential autonomic regulatory mechanisms which may account for these findings, the relation between short-term heart rate variability (HRV) and respiratory activity was analyzed in a group of eight ASA grade II former premature infants undergoing high thoracic spinal anesthesia for inguinal hernia repairs. Quantitative measures of sympathetic (As) and parasympathetic (Ap) modulation of HR were derived. HR, arterial blood pressure, and a calibrated respiratory signal were recorded during 4.4-min stable epochs in eight subjects 1) preoperatively, 2) postincision after high thoracic spinal anesthesia, and 3) during an active sleep state in the postoperative period. Power spectral analysis of HRV and respiratory power yielded measures of low-frequency power (LFP: 0.02-0.15 Hz) and high-frequency power (HFP: 0.15-0.8 Hz). Transfer function analysis between respiratory activity and HR were used to quantify As and Ap. All subjects had successful high thoracic spinal anesthesia with highest levels ranging from C7-T4. Mean HR, blood pressure, and respiratory power did not change significantly with high thoracic spinal anesthesia. LFP and HFP both decreased significantly, whereas the LFP/HFP ratio remained stable. Group mean As and Ap both decreased, but the changes were not significant. Despite overall cardiovascular stability, HRV decreased with high thoracic spinal anesthesia, but the balance between LFP and HFP remained stable, suggesting that the reflex response to high thoracic spinal anesthesia was predominantly diminished parasympathetic modulation of cardiac function. The expected decrease in HR and blood pressure from the sympatholysis which results from high thoracic spinal anesthesia were apparently offset by withdrawal of cardiac vagal activity.
与成人不同，新生儿能耐受高位胸椎脊髓麻醉，心率（HR）和动脉血压变化极小。为研究可能解释这些发现的潜在自主调节机制，我们分析了一组8名美国麻醉医师协会（ASA）分级为II级的 former 早产儿在接受高位胸椎脊髓麻醉进行腹股沟疝修补术时短期心率变异性（HRV）与呼吸活动之间的关系。得出了交感神经（As）和副交感神经（Ap）对HR调节的定量指标。在8名受试者的4.4分钟稳定时段内记录HR、动脉血压和校准后的呼吸信号，分别在1）术前，2）高位胸椎脊髓麻醉后切开时，以及3）术后活跃睡眠状态下进行记录。HRV的功率谱分析和呼吸功率得出低频功率（LFP：0.02 - 0.15Hz）和高频功率（HFP：0.15 - 0.8Hz）的测量值。呼吸活动与HR之间的传递函数分析用于量化As和Ap。所有受试者高位胸椎脊髓麻醉均成功，最高平面范围为C7 - T4。高位胸椎脊髓麻醉后平均HR、血压和呼吸功率无显著变化。LFP和HFP均显著降低，而LFP/HFP比值保持稳定。组平均As和Ap均降低，但变化不显著。尽管总体心血管稳定，但高位胸椎脊髓麻醉后HRV降低，但LFP和HFP之间的平衡保持稳定，这表明对高位胸椎脊髓麻醉的反射反应主要是心脏功能的副交感神经调节减弱。高位胸椎脊髓麻醉导致的交感神经阻滞预期的HR和血压下降显然被心脏迷走神经活动的减弱所抵消。 （注：原文中“former”此处含义不太明确，可能是记录有误之类的情况，暂按原文翻译）
