Zheng Gang, Dong Wenli, Lewis Carol M
From the Departments of Anesthesiology and Perioperative Medicine.
Biostatistics.
Anesth Analg. 2017 Dec;125(6):2056-2062. doi: 10.1213/ANE.0000000000002539.
Head and neck radiation therapy (HNRT) impairs baroreflex sensitivity, and it may potentiate the effects of anesthetics on heart rate (HR) and blood pressure (BP) regulation. Currently, the impacts of HNRT on HR and BP under anesthesia remain unclear.
In this study, 472 patients with primary oral cavity or oropharyngeal cancer at all stages were examined. Half of the patients underwent HNRT plus surgery. The other half underwent surgery only and was matched with the treatment patients according to age, sex, and body mass index at a 1:1 ratio. The HRs and BPs in the 2 groups during anesthetic induction, skin incision, and emergence were compared retrospectively. A multivariable model of repeated measures with unstructured covariance structure was used to examine the associations of HNRT with intraoperative HRs and BPs after adjusting for baseline HR and BP, time, use of β-blockers, history of chemotherapy, and American Society of Anesthesiologists physical status score. BPs and HRs were collected every 5 minutes. The baseline HR and BP measurements were not included in the outcome vector and were only used as adjustment for baselines.
Compared with corresponding baseline values in controls, the baseline HR was significantly higher (P = .0012) and the baseline systolic BP was lower (P < .0001) in the treatment group. The baseline diastolic BP levels did not differ significantly (P = .6411). Fewer patients receiving HNRT than controls took β-blockers daily (17% vs 28%; P = .0041). Comparing the corresponding values in control and treatment groups, multivariable analysis revealed significant associations of HNRT with decreases in HR during anesthesia induction (-2.21 [95% confidence interval {CI}, -4.42 to -0.01]; P = .0492) and skin incision (-2.66 [95% CI, -5.16 to -0.16]; P = .0373) and of HNRT with decreases in systolic BP during anesthesia induction (-6.88 [95% CI, -10.99 to -2.78]; P = .0011) and skin incision (-15.87 [95% CI, -20.45 to -11.29]; P < .001). However, we observed a significant association of HNRT with decrease in diastolic BP only during skin incision (-6.50 [95% CI, -9.47 to -3.53]; P < .0001).
The significant finding in the study was that general anesthesia imposed a negative chronotropic effect on HR in the group given HNRT. Therefore, one should be watchful for bradycardia in these patients; particularly those with low BPs. Their hemodynamics may rapidly progress into an unstable status when bradycardia and hypotension develop altogether.
头颈部放射治疗（HNRT）会损害压力反射敏感性，可能会增强麻醉药对心率（HR）和血压（BP）调节的影响。目前，HNRT对麻醉状态下HR和BP的影响尚不清楚。
本研究对472例各期原发性口腔或口咽癌患者进行了检查。一半患者接受HNRT加手术治疗。另一半仅接受手术治疗，并根据年龄、性别和体重指数与治疗组患者以1:1的比例进行匹配。回顾性比较两组患者在麻醉诱导、皮肤切开和苏醒期间的HR和BP。采用具有非结构化协方差结构的重复测量多变量模型，在调整基线HR和BP、时间、β受体阻滞剂的使用、化疗史和美国麻醉医师协会身体状况评分后，研究HNRT与术中HR和BP的相关性。每5分钟收集一次BP和HR。基线HR和BP测量值不包括在结果向量中，仅用作基线调整。
与对照组相应的基线值相比，治疗组的基线HR显著更高（P = 0.0012），基线收缩压更低（P < 0.0001）。基线舒张压水平无显著差异（P = 0.6411）。接受HNRT的患者每日服用β受体阻滞剂的人数少于对照组（17%对28%；P = 0.0041）。多变量分析比较对照组和治疗组的相应值，结果显示HNRT与麻醉诱导期间HR降低（-2.21[95%置信区间{CI}，-4.42至-0.01]；P = 0.0492）和皮肤切开时HR降低（-2.66[95%CI，-5.16至-0.16]；P = 0.0373）以及HNRT与麻醉诱导期间收缩压降低（-6.88[95%CI，-\(10.99至-2.78]；P = 0.0011）和皮肤切开时收缩压降低（-15.87[95%CI，-20.45至-11.29]；P < 0.001）显著相关。然而，我们仅在皮肤切开时观察到HNRT与舒张压降低显著相关（-6.50[95%CI，-9.47至-3.53]；P < 0.0001）。
该研究的重要发现是，全身麻醉对接受HNRT的患者的HR有负性变时作用。因此，应警惕这些患者出现心动过缓；尤其是那些血压较低的患者。当心动过缓和低血压同时发生时，他们的血流动力学可能会迅速进入不稳定状态。
