고양이에서 체표냉각에 따른 심혈관계 변동에 관한 연구

• 영문명: Cardiovascular Changes of Cat in Hypothermia
• 발행기관: 대한약리학회
• 저자명: 안영수(Young Soo Ahn) 고창만(Chang Mann Ko) 이우주(Woo Choo Lee)
• 간행물 정보: 『대한약리학잡지』제19권 제1호, 61~70쪽, 전체 10쪽
• 주제분류: 의약학 > 기타의약학
• 파일형태: PDF
• 발행일자: 1983.06.30

영문 초록

Hypothermia is an essential preparatory procedure for cardiac surgery, which lows the metabolic rate and myocardial oxygen demand. However, hypothermia itself is a stress enough to change the tonus of sympathoadrenal system, especially the cardiovascular responses to the catecholamines. It is reported that the positive chronotropic and inotropic response of catecholamines is exaggerated during hypothermia because of decreased norepinephrine uptake at the junctional cleft or decreased catecholamine metabolism. On the other hand, there are evidences of diminished catecholamines responses in low temperature ana further, interconversion of adrenergic receptors is also suggested. Present investigation was planned to observe the cardiovascular changes and its responses to catecholamines during surface hypothermia in cat. Healthy mongrel cats, weighing 2 ~ 3 kg, anesthetized with secobarbital(30 mg/kg), were permitted to hypothermia by external cooling technic. Esophageal temperature, ECG (lead II), heart rate, left ventricular pressure with dP/dt, carotid artery pressure and left ventricular contractile force were monitored with Polygragh (Model 7, Grass), and the respiration was maintained with artificial respirator (V 5 KG, Narco). Followings are summarized results. 1) Surface cooling caused progressive decrease of body temperature and reached l8.8 ± 0.8˚C and 16.9 ± 0.6˚C in 120 and 150 min respectively, after immersion into ice water, and ventricular fibrillation was developed at 20.4 ± 0.65˚C. 2) Heart rate, blood pressure and myocardial contractility were decreased after initial increase as the body temperature falls. 3) Systolic and diastolicdd P/dt of left ventricular pressure were decreased and that the decrement of diastolic dP/dt was more marked. 4) On ECG, ST depression, Twave inversion and prolongation of PR interval were prominent in hypothermia, and moreover, the prolongation of PR interval was marked just prior to the development of ventricular fibrillation. 5) The cardiovascular responses to catecholamines, especially to isoproterenol, were suppressed under hypothermia.