Effects of pericardial administration of lidocaineon hemodynamic responses.

背景：缺血性心脏病患者麻醉时应尽量避免心动过速，特别是在非体外循环冠状动脉搭桥术中需要控制心率。降低心率而不改变心脏收缩力是理想的心率控制。为了达到这一目的，我们尝试通过在心包间隙注射局麻药来阻断心神经。方法：为观察局麻药输注心包间隙对血流动力学和心律失常的影响，我们对麻醉、机械通气、置有肺导管的狗进行了研究。每10只狗灌注2.5或5ml 1%利多卡因，5mi 2%利多卡因或生理盐水。在心包有利多卡因（1%）存在的情况下，我们观察了心脏对静脉注射阿托品或异丙肾上腺素的反应。此外，为了研究利多卡因对心包心律失常的抑制作用，我们还安装了电颤仪来测定诱发心律失常或心室颤动的电压。同时用6只狗测定血清利多卡因浓度。结果：心包给药利多卡因可迅速降低心率（HR） （5min内较对照组降低约80%，p<0.05），且呈剂量依赖性，卒中容积（SV）无显著变化。心包有利多卡因时，异丙肾上腺素对HR的反应显著，但与没有心包有利多卡因时相似。然而，心包利多卡因完全阻断了HR对阿托品的反应。静脉注射与心包输注两组血浆利多卡因浓度变化完全不同。静脉注射利多卡因立即升高利多卡因血药浓度，心包输注利多卡因在给药后10min升高利多卡因血药浓度。心包利多卡因升高心律失常和室颤阈值（由1.6V升高至2.2V, p<0.01）。结论：心包给药利多卡因能很好地控制HR，并能维持HR对异丙肾上腺素的反应，但完全阻断HR对阿托品的反应。对电颤器诱发的心律失常和心室颤动有抑制作用。这些结果表明，心包利多卡因可能适用于非体外循环冠状动脉搭桥术中HR的控制。少

Background : Tachycardiac responses during anesthesia should be better to avoid in the patients who have ischemic heart disease, especially during off-pump coronary artery bypass grafting surgery that needs the control of heart rate. Decrease of heart rate without change of cardiac contractility is ideal control of heart rate. In order to achieve this purpose, we tried to block the cardiac nerve with injection of local anesthetics given into the pericardial space. Methods : To examine whether a local anesthetic infusion into the pericardial space affects hemodynamics and arrhythmogenicity, we studied anesthetized, mechanical ventilated dogs having pulmonary catheter in place. We perfused the pericardial space with 2.5 or 5ml of 1% lidocaine, 5mi of 2% lidocaine, or normal saline solution for each 10 dogs. In the presence of pericardial lidocaine (1%), we observed the cardiac responses to intravenous atropine or isoproterenol. Further, to examine the inhibitory action to arrhythmia of p … More ericardial lidocaine, an electrical fibrillator was installed to decide the voltage of inducing arrhythmia or ventricular fibrillation. Also six dogs were used for measurement of serum concentration of lidocaine. Results : The pericardial administration of lidocaine soon decreased heart rate (HR) (about 80% from control within 5min, p<0.05), dose-dependently and significantly without changes in stroke volume (SV). In the presence of pericardial lidocaine, HR responses to isoproterenol were significant, but similar to that without pericardial lidocaine. However, HR response to atropine was completely blocked with pericardial lidocaine. Changes of plasma lidocaine concentration were completely different between intravenous injection and pericardial infusion. Intravenous injection of lidocaine elevated plasma concentration of lidocaine immediately, whereas the pericardial infusion of lidocaine elevated it 10min after its administration. The pericardial lidocaine rose the threshold for arrhythmia and ventricular fibrillation (from 1.6V to 2.2V, p<0.01). Conclusions : Pericardial administration of lidocaine well controlled HR, and could preserve HR responses to isoproterenol, but completely blocked HR responses to atropine. And it inhibited arrhythmia and ventricular fibrillation induced by electrical fibrillator. These results suggest that pericardial lidocaine may be suitable for control of HR during off-pump coronary artery bypass grafting surgery. Less