Haneda K, Thomas R, Breazeale D G, Sands M P, Dillard D H
J Cardiovasc Surg (Torino). 1984 Jan-Feb;25(1):67-74.
Thirty adult mongrel dogs were divided into 3 equal groups and studied to define the optimal PCO2 level with azeotrope (halothane-diethyl ether) anesthesia under surface hypothermia (Groups I, II and III = F1CO2 0%, 5% and 10%, respectively). All animals were cooled to 18-20 degrees C and were subjected to 30 (Group I) or 60 minutes (Groups II and III) of total circulatory arrest. Group I animals had frequent arrhythmic episodes during cooling and postoperative motor disturbances occurred in 80% despite only 30 minutes of circulatory arrest. By contrast Group II animals were less arrhythmic during cooling; were easily resuscitated following 60 minutes of arrest and only 30% developed moderate reversible motor disturbances postoperatively. Hemodynamics were similar between Groups II and III during cooling but resuscitation using an F1CO2 of 10% (Group III) was extremely difficult and required massive cardiotonic support throughout rewarming. Furthermore, two dogs in Group III died within the first two postoperative days. However, none of the 8 survivors displayed neurological abnormalities. On balance, a ventilatory regimen utilizing 5% CO2 during surface-induced hypothermia under azeotrope anesthesia resulted in optimum intraoperative management and a satisfactory postoperative course and although some CNS disturbance (high-stepping gait) was noted, all animals recovered completely.
30只成年杂种犬被分成3组，每组数量相等，旨在确定在表面低温下使用共沸物（氟烷 - 乙醚）麻醉时的最佳二氧化碳分压水平（第I、II和III组的呼气末二氧化碳分压分别为0%、5%和10%）。所有动物均被冷却至18 - 20摄氏度，并经历30分钟（第I组）或60分钟（第II和III组）的完全循环停止。第I组动物在冷却过程中频繁出现心律失常，尽管仅循环停止30分钟，但80%的动物术后出现运动障碍。相比之下，第II组动物在冷却过程中心律失常较少；在60分钟的循环停止后易于复苏，术后仅有30%出现中度可逆性运动障碍。第II组和第III组在冷却过程中的血流动力学相似，但使用10%的呼气末二氧化碳分压（第III组）进行复苏极其困难，在整个复温过程中需要大量强心支持。此外，第III组中有两只犬在术后前两天内死亡。然而，8只存活犬均未表现出神经异常。总体而言，在共沸物麻醉下表面诱导低温期间采用5%二氧化碳的通气方案可实现最佳的术中管理和令人满意的术后过程，尽管注意到一些中枢神经系统干扰（高抬腿步态），但所有动物均完全康复。
