Small Animal Clinic, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, 30559, Hannover, Germany.
Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
BMC Vet Res. 2019 Jul 24;15(1):258. doi: 10.1186/s12917-019-2004-8.
Heart rate variability (HRV) provides information about autonomic nervous system (ANS) activity and is therefore a possible tool with which to assess anaesthetic depth. The aim of the present study was to evaluate the effects of isoflurane, remifentanil and dexmedetomidine on HRV before and after nociceptive stimulation at different anaesthetic depths. Seven healthy domestic short-hair cats were used, and each cat was anaesthetized three times - group I with isoflurane alone, group IR with isoflurane and a constant rate infusion (CRI) of remifentanil (18 μg/kg/h), and group ID with isoflurane and a CRI of dexmedetomidine (3 μg/kg/h). Minimum alveolar concentration (MAC) values were determined via electrical supramaximal nociceptive stimulation for each treatment group. Nociceptive stimulation was repeated at 3 different MAC multiples (0.75, 1.0 and 1.5 MAC), and electrocardiographic recordings were performed for 3 min before and after stimulation. Only the 1 min epochs were used for further statistical analysis. Electrocardiographic data were exported for offline HRV analysis.
The mean isoflurane MAC ± standard deviation (SD) was 1.83 ± 0.22 vol% in group I, 1.65 ± 0.13 vol% in group IR and 0.82 ± 0.20 vol% in group ID. Nociception was indicated by several HRV parameters, however, with high variability between treatments. The best correlation with MAC was found for the SD of heart rate (STD HR) in group I (r = - 0.76, p = 0.0001, r = 0.46). STD HR was also able to distinguish 0.75 MAC from 1.5 MAC and 1.0 MAC from 1.5 MAC in group I, as well as 0.75 MAC from 1.5 MAC in group ID.
The choice of anaesthetic protocol influences the HRV parameters in cats. Frequency domain parameters respond to nociception at lower MAC levels. The STD HR has the potential to provide additional information for the assessment of anaesthetic depth in isoflurane-anaesthetized cats. The utility of HRV analysis for the assessment of anaesthetic depth in cats is still questionable.
心率变异性（HRV）提供了自主神经系统（ANS）活动的信息，因此可能是评估麻醉深度的一种工具。本研究的目的是评估异氟醚、瑞芬太尼和右美托咪定在不同麻醉深度下痛觉刺激前后对 HRV 的影响。使用了 7 只健康的家短毛猫，每只猫麻醉 3 次-组 I 单独使用异氟醚，组 IR 使用异氟醚和瑞芬太尼（18μg/kg/h）恒速输注（CRI），组 ID 使用异氟醚和右美托咪定（3μg/kg/h）CRI。为每个治疗组通过电刺激超最大痛觉确定最小肺泡浓度（MAC）值。在 3 个不同的 MAC 倍数（0.75、1.0 和 1.5 MAC）下重复痛觉刺激，并在刺激前后进行 3 分钟的心电图记录。仅使用 1 分钟的时间片段进行进一步的统计分析。导出心电图数据进行离线 HRV 分析。
组 I 的平均异氟醚 MAC ± 标准偏差（SD）为 1.83 ± 0.22 体积%，组 IR 为 1.65 ± 0.13 体积%，组 ID 为 0.82 ± 0.20 体积%。疼痛刺激通过几个 HRV 参数来表示，但治疗之间的变异性很大。与 MAC 相关性最好的是组 I 中的心率标准差（STD HR）（r=-0.76，p=0.0001，r=0.46）。STD HR 还能够区分组 I 中的 0.75 MAC 与 1.5 MAC 和 1.0 MAC 与 1.5 MAC，以及组 ID 中的 0.75 MAC 与 1.5 MAC。
麻醉方案的选择会影响猫的 HRV 参数。频域参数在较低的 MAC 水平下对痛觉刺激有反应。STD HR 有可能为评估异氟醚麻醉猫的麻醉深度提供额外信息。HRV 分析在评估猫的麻醉深度方面的实用性仍存在疑问。
