Ueyama K, Jones J W, Varvitsiotis P S, LaFuente J A, Thornby J I, Raskin S A, Beall A C
Baylor College of Medicine, Department of Surgery, Veterans Affair Medical Center, Houston, Texas, USA.
Biomed Mater Eng. 1996;6(3):191-7.
Heat exchange methods must be efficient in order to minimize the patient's pump time. However, comparisons of heat exchangers have been rare. Therefore, the in vivo functions of the most popular, currently available heat exchangers, Sarns, Cobe, Medtronics Maxima, and an experimental model manufactured by Haemonetics were compared. Thirty-two pigs weighing between 63-74 kg were placed on cardiopulmonary bypass with right atrial and ascending aorta cannulation through a right thoracotomy. Thermocouples were placed in the pump tubing before and after the heat exchangers, in the water line before and after the heat exchangers, in the inlet and outlet line of the pump, and the esophagus, brain, bladder, rectum, liver, myocardium, and tympanic membranes of the pigs. They were cooled until the bladder temperature was reduced to 14 degrees C, and maintained at that temperature for 10 minutes. Rewarming was begun until the bladder temperature became 37 degrees C. The pump flow was maintained between 50-60 ml/kg/min with standard ventilation. Cobe, Sarns, Maxima, and Haemonetics heat exchangers were tested and their function determined by comparing the time necessary for rewarming. The Haemonetics heat exchanger required a significant shorter time than the others to rewarm the pigs to normal bladder temperature (Cobe 82.0 +/- 12.0, Sarns 80.3 +/- 15.4, Maxima 89.0 +/- 13.9 Haemonetics 68.7 +/- 13.4, p < 0.05). The principal advantage was seen at the lowest temperatures between the Haemonetics experimental heat exchanger and the other heat exchangers. No statistically significant superiority was seen at higher temperatures. The current heat exchangers are relatively comparable but improved performance is possible with available technology.
为了尽量缩短患者的体外循环时间，热交换方法必须高效。然而，对热交换器的比较却很少见。因此，对目前最常用的热交换器——Sarns、Cobe、美敦力Maxima以及一款由Haemonetics公司制造的实验模型的体内功能进行了比较。32头体重在63至74千克之间的猪通过右胸切口进行右心房和升主动脉插管，置于体外循环中。热电偶分别置于热交换器前后的泵管中、热交换器前后的水管中、泵的进出口管路中以及猪的食管、脑、膀胱、直肠、肝脏、心肌和鼓膜处。将它们冷却至膀胱温度降至14摄氏度，并在该温度下维持10分钟。开始复温直至膀胱温度达到37摄氏度。在标准通气情况下，泵流量维持在50至60毫升/千克/分钟。对Cobe、Sarns、Maxima和Haemonetics热交换器进行了测试，并通过比较复温所需时间来确定它们的功能。与其他热交换器相比，Haemonetics热交换器使猪复温至正常膀胱温度所需的时间明显更短（Cobe为82.0±12.0分钟，Sarns为80.3±15.4分钟，Maxima为89.0±13.9分钟，Haemonetics为68.7±13.4分钟，p<0.05）。主要优势体现在Haemonetics实验性热交换器与其他热交换器在最低温度时的比较。在较高温度下未观察到统计学上的显著优势。目前的热交换器性能相对可比，但利用现有技术仍有可能提高性能。
