| Co-Investigator(Kenkyū-buntansha) |
DOHI Shuji Gifu University, School of Medicine, Professor, 医学部, 教授 (40155627)
TERAZAWA Etsuji Gifu University, School of Medicine, Research Associate, 医学部附属病院, 助手 (90180075)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 2003: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2002: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
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
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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
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