Novitzky D, Human P A, Cooper D K
Department of Cardiothoracic Surgery, University of Cape Town Medical School, South Africa.
Ann Thorac Surg. 1988 Jan;45(1):50-5. doi: 10.1016/s0003-4975(10)62396-x.
A significant reduction (p less than 0.0001) in plasma-free triiodothyronine (T3), which is known to have an inotropic effect, has been documented in patients undergoing open-heart procedures. To investigate the effect of this observation, 22 pigs underwent 2 hours (Group 1, r = 10) or 3 hours (Group 2, r = 12) of myocardial ischemia during cardiopulmonary bypass (CPB) at 26 degrees C; the myocardium was protected by cardioplegic solution and cold saline solution at 30-minute intervals. After the pig was rewarmed to 37 degrees C, CPB was discontinued, and measurements of hemodynamic function were made 10 and 70 minutes later. Half of the pigs (Subgroup B) received 6 micrograms of T3 intravenously immediately after removal of the aortic cross-clamp; the remainder (Subgroup A) received no T3. After 2 hours of ischemia, untreated pigs showed significantly reduced myocardial function 10 minutes after discontinuation of CPB. By 70 minutes after the end of CPB, 2 of 5 untreated pigs (Subgroup A) had died of low cardiac output, but all 5 treated pigs (Subgroup B) survived. After 3 hours of ischemia, both groups showed some reduced function at 10 minutes, though the reduction was more marked in untreated animals. By 70 minutes, 4 of 6 untreated pigs had died of myocardial failure and all treated pigs remained alive (p less than 0.03). Surviving pigs in both groups still demonstrated some reduced function compared with values obtained before CPB. When all pigs are considered together, overall survival of those that did not receive T3 was significantly less than those that did (p less than 0.006).(ABSTRACT TRUNCATED AT 250 WORDS)
已知具有正性肌力作用的游离三碘甲状腺原氨酸（T3）血浆水平在接受心脏直视手术的患者中显著降低（p<0.0001）。为研究这一现象的影响，22头猪在26℃体外循环（CPB）期间经历了2小时（第1组，r = 10）或3小时（第2组，r = 12）的心肌缺血；每隔30分钟用心脏停搏液和冷盐溶液保护心肌。猪复温至37℃后，停止CPB，并在10分钟和70分钟后测量血流动力学功能。一半的猪（B亚组）在移除主动脉夹后立即静脉注射6微克T3；其余猪（A亚组）未接受T3。缺血2小时后，未治疗的猪在CPB停止10分钟后心肌功能显著降低。CPB结束70分钟时，5头未治疗的猪（A亚组）中有2头死于低心输出量，但所有5头治疗的猪（B亚组）均存活。缺血3小时后，两组在10分钟时均显示功能有所降低，尽管未治疗动物的降低更为明显。到70分钟时，6头未治疗的猪中有4头死于心肌衰竭，所有治疗的猪均存活（p<0.03）。与CPB前的值相比，两组存活的猪仍显示功能有所降低。当将所有猪一起考虑时，未接受T3的猪的总体存活率显著低于接受T3的猪（p<0.006）。（摘要截断于250字）
