Takach T J, Glassman L R, Ribakove G H, Clark R E
Ann Thorac Surg. 1986 Jul;42(1):31-6. doi: 10.1016/s0003-4975(10)61832-2.
The continuous measurement of intramyocardial pH was used to follow the progression of ischemia and was correlated to the recovery of left ventricular function following normothermic (38 degrees C) and hypothermic (25 degrees C) global ischemia. New miniature myocardial transducers, which incorporate fiberoptic technology and dual pH- and temperature-sensing capability, were placed into the left ventricular free wall and septum of 52 sheep undergoing cardiopulmonary bypass. Left ventricular stroke work as a function of mean left atrial pressure curves were generated before and after cardiopulmonary bypass by volume loading with whole blood. Functional recovery was determined by the ratio of the integrals of the preischemic and postischemic function curves. Control sheep (N = 11) did not undergo ischemia. Three groups (N = 41) underwent aortic cross-clamping until pH reached 7.0, 6.8, or 6.6. The preischemic myocardial pH averaged 7.42 +/- 0.01. Following both normothermic and hypothermic global ischemia, no significant difference was demonstrated in recovery of function between control (pH 7.4) and pH 7.0 groups at either temperature. However, recovery of function of the pH 6.8 and pH 6.6 groups was significantly decreased (p less than 0.01) versus control and pH 7.0 groups at both temperatures. No significant difference in recovery of function was demonstrated at any pH level when normothermic versus hypothermic groups were compared. However, hypothermia provided increased time (p less than 0.001) before each level of function was reached with a slower rate of change of pH (p less than 0.01) compared with the corresponding same pH group in sheep undergoing normothermic (38 degrees C) cardiopulmonary bypass.(ABSTRACT TRUNCATED AT 250 WORDS)
采用连续测量心肌内pH值的方法来跟踪缺血进展情况，并将其与常温（38摄氏度）和低温（25摄氏度）全心缺血后左心室功能的恢复情况进行关联。将采用光纤技术且具备双pH值和温度传感能力的新型微型心肌传感器，植入52只接受体外循环的绵羊的左心室游离壁和室间隔。在体外循环前后，通过输入全血进行容量负荷，生成左心室每搏功与平均左心房压力的关系曲线。功能恢复情况由缺血前和缺血后功能曲线积分的比值来确定。对照绵羊（N = 11）未经历缺血。三组（N = 41）进行主动脉交叉钳夹，直至pH值达到7.0、6.8或6.6。缺血前心肌pH值平均为7.42±0.01。在常温及低温全心缺血后，在任一温度下，对照（pH 7.4）组和pH 7.0组之间的功能恢复情况均无显著差异。然而，在两个温度下，pH 6.8组和pH 6.6组的功能恢复情况与对照及pH 7.0组相比均显著降低（p < 0.01）。比较常温组和低温组时，在任何pH水平下功能恢复情况均无显著差异。然而，与接受常温（38摄氏度）体外循环的绵羊中相应相同pH组相比，低温可在达到每个功能水平之前提供更长时间（p < 0.001），且pH值变化速率更慢（p < 0.01）。（摘要截选至250字）
