Schubert A, Palazzolo J A, Brum J M, Ribeiro M P, Tan M
Department of General Anesthesiology, Cleveland Clinic Foundation, OH 44195, USA.
J Clin Anesth. 1997 Feb;9(1):52-60. doi: 10.1016/S0952-8180(96)00208-5.
To define the behavior of power spectral heart rate variability (PSHR) during potentially stressful events in the perioperative period, and relate it to changes in blood pressure (BP) and heart rate (HR).
Longitudinal clinical study.
Operating room and recovery suites of a large tertiary care referral center.
26 ASA physical status I, II, and III patients undergoing elective abdominal surgery.
Anesthesia was induced with thiopental sodium and fentanyl, and maintained with isoflurane/nitrous oxide (N2O)/relaxant or enflurane/N2O/relaxant. The trachea was intubated and intraabdominal surgery was performed.
Observations consisted of HR, noninvasive blood pressure, and PSHR. They were made before and after induction of anesthesia, tracheal intubation, and surgical incision, and during maximal surgical stimulation and skin closure. HR and mean arterial pressure (MAP) maxima were also recorded for one hour before and after emergence from anesthesia. PSHR was obtained using a special algorithm and data acquisition system for real time spectral analysis of the instantaneous HRversus time function. The HR power spectrum parameters analyzed were low-frequency (LFA; powerband = 0.04 to 0.10 Hz), respiratory-induced frequency (RFA; powerband = respiratory frequency +/- 0.06 Hz), and the ratio of LFA to RFA. With induction of anesthesia, only RFA power decreased significantly. LFA power reduction became significant only after intubation and continued so until after incision. Immediately after induction, the decline in RFA power (vs. preinduction) was more pronounced when compared with the decline in LFA power (76% vs. 34%; p = 0.01). Hence, the ratio LFA/RFA increased significantly after induction of anesthesia. It was significantly higher than at postintubation, preincision, or skin closure. A significant elevation in LFA, LFA/RFA ratio, and BP occurred with maximal abdominal surgical stimulation. Only preinduction LFA, RFA, and LFA/ RFA ratio were predictive of MAP changes with induction of anesthesia (p = 0.006). In 8 of the 15 patients who had MAP changes of at least 10 mmHg with induction, PSHR indices correctly predicted a change of this magnitude. Late intraoperative HR maxima were positively correlated with the change in HR and incision (r2 = 0.58; p < 0.01). The change in BP with incision was positively correlated with early postoperative HR maxima (r2 = 0.60; p < 0.01).
On anesthetic induction, preoperative, but not intraoperative, spectral indices were predictive of BP changes. Power spectral analysis of HR may provide information about the autonomic state that is not evident from BP or HR. The HR power spectrum, in particular, indicated a striking autonomic imbalance immediately after the induction of anesthesia despite stable HR and BP. LFA and LFA/RFA ratio appeared to track sympathetic autonomic activation during abdominal surgical stimulation, but not during other perioperative stressor events.
明确围手术期潜在应激事件期间心率变异性功率谱（PSHR）的变化情况，并将其与血压（BP）和心率（HR）的变化相关联。
纵向临床研究。
一家大型三级医疗转诊中心的手术室和恢复室。
26例美国麻醉医师协会（ASA）身体状况为I、II和III级的择期腹部手术患者。
采用硫喷妥钠和芬太尼诱导麻醉，并用异氟烷/氧化亚氮（N2O）/肌肉松弛剂或安氟醚/N2O/肌肉松弛剂维持麻醉。气管插管后进行腹部手术。
观察指标包括心率、无创血压和PSHR。在麻醉诱导前、气管插管前后、手术切口前后以及最大手术刺激和皮肤缝合期间进行观察。同时记录麻醉苏醒前后1小时的心率和平均动脉压（MAP）最大值。使用一种特殊算法和数据采集系统获取PSHR，以对瞬时心率与时间函数进行实时频谱分析。分析的心率功率谱参数包括低频（LFA；功率范围 = 0.04至0.10赫兹）、呼吸诱导频率（RFA；功率范围 = 呼吸频率±0.06赫兹）以及LFA与RFA的比值。麻醉诱导时，只有RFA功率显著下降。LFA功率仅在插管后才显著降低，并持续至切口后。诱导后立即观察到，与LFA功率下降相比，RFA功率下降更为明显（76%对34%；p = 0.01）。因此，麻醉诱导后LFA/RFA比值显著升高。该比值显著高于插管后、切口前或皮肤缝合时。腹部手术最大刺激时，LFA、LFA/RFA比值和血压显著升高。仅诱导前的LFA、RFA和LFA/RFA比值可预测麻醉诱导时的MAP变化（p = 0.006）。在15例诱导时MAP变化至少10 mmHg的患者中，有8例的PSHR指标正确预测了这种幅度的变化。术中晚期心率最大值与心率变化和切口呈正相关（r2 = 0.58；p < 0.01）。切口时血压变化与术后早期心率最大值呈正相关（r2 = 0.60；p < 0.01）。
麻醉诱导时，术前而非术中的频谱指标可预测血压变化。心率功率谱分析可能提供从血压或心率中不明显的自主神经状态信息。特别是，尽管心率和血压稳定，但麻醉诱导后心率功率谱显示出明显的自主神经失衡。LFA和LFA/RFA比值似乎可追踪腹部手术刺激期间的交感神经自主激活，但在其他围手术期应激事件期间则不然。
