RESUMO
BACKGROUND: The measurement of perfusion is very important to understanding the physiology in the ischemic and reperfused tissue. However, no studies have been reported using a beating heart with a real time-continuous perfusion measurement system (QFlow(TM)400) to check local tissue perfusion so far. In this study, the changes in hemodynamics and local myocardial perfusion (LMP) after coronary reperfusion with nicardipine (a calcium channel blocker) administration were evaluated. METHODS: A total of 10 mongrel dogs were divided into two groups; group I (control group, n = 5), group II (nicardipine group, n = 5). After femoral arterial, pulmonary arterial and left ventricular catheterization, a left thoracotomy was performed. Next, the left anterior descending coronary artery (LAD) was exposed, and a thermal diffusion microprobe was inserted in the myocardium to measure LMP. RESULTS: In group II, blood pressure and systemic vascular resistance after LAD reperfusion were significantly decreased compared to group I. Cardiac output and stroke volume were more rapidly increased in group II, while left ventricular stroke work was decreased in group II. In group I, the LMP after LAD reperfusion did not recover to the baseline level, but the LMP did recover 20 minutes after LAD reperfusion and was increased more compared to the baseline level at 30 minutes after LAD reperfusion in group II. There were no significant differences in dP/dt between the two groups. CONCLUSIONS: We found that the LMP did not recover to the baseline level in the early state of LAD reperfusion; however, nicardipine administration increased the LMP after the early reperfusion period. Cardiac output and stroke volume were also more rapidly increased when nicardipine was administrated.
Assuntos
Animais , Cães , Pressão Sanguínea , Canais de Cálcio , Débito Cardíaco , Cateterismo , Catéteres , Vasos Coronários , Coração , Hemodinâmica , Reperfusão Miocárdica , Miocárdio , Nicardipino , Perfusão , Fisiologia , Reperfusão , Acidente Vascular Cerebral , Volume Sistólico , Difusão Térmica , Toracotomia , Resistência VascularRESUMO
Drugs for acute blood pressure control are often required during a cardiovascular operation. Hypertension frequently occurs in an off-pump coronary artery bypass graft. The purpose of this study was to evaluate the effect of nicardipine on hemodynamic change. Twenty adult patients were studied. Anesthesia was induced intravenously with thiopental (4 mg/kg), vecuronium (1 mg/kg), and fentanyl (4microgram/kg), and maintained with 100% O2 and isoflurane 1 1.5 Vol%. When systolic blood pressure rose above 150 mmHg, nicardipine 1 mg was administrated intravenously. Immediately after the nicardipine bolus injection, nicardipine was infused continuously 0.5 4microgram/kg/min. Thereafter, hemodynamic data was recorded. Systolic blood pressure decreased, but cardiac index significantly increased after an intravenous administration of nicardipine and was maintained during the study. There was no incidence of tachycardia. It was concluded that acute blood pressure control using nicardipine could be suitable and safe in patients with an off-pump CABG.