Pepine C J
Chest. 1977 Jul;72(1):72-8. doi: 10.1378/chest.72.1.72.
The effect of increased intrathoracic pressure on coronary hemodynamics and coronary venous oxygen tension was evaluated in surgically instrumented dogs. Following abrupt increase in intrathoracic pressure, as systolic pressure decrease, the tension time index (TTI) fell 83 percent (P less than 0.001) compared to control. The diastolic pressure time index (DPTI) decline proportionately less, effecting an increase in the ratio of DPTI/TTI from 1.19 +/- 0.08 to 1.78 +/- 0.16 (P LESS THAN 0.05). The mean circumflex coronary blood flow declined only minimally toward the end of the test (5.1 +/- 9.0 ml/min; P less than 0.05), and stroke systolic circumflex coronary blood flow increased 116 percent (P less than 0.01) as late diastolic coronary resistance decreased 31 percent (P less than 0.01). The mean coronary venous oxygen pressure increased transiently above control values from 21 +/- 1 to 24 +/- 2 mm Hg (P less than 0.05). These data suggest that in anesthetized dogs, brief periods of high intrathoracic pressure abruptly reduce determinants of myocardial demand for oxygen, while myocardial perfusion decreases to a lesser degree.
在通过外科手术植入仪器的犬类中，评估了胸腔内压力升高对冠状动脉血流动力学和冠状静脉血氧张力的影响。胸腔内压力突然升高后，随着收缩压下降，与对照组相比，张力时间指数（TTI）下降了83%（P<0.001）。舒张压时间指数（DPTI）下降幅度相对较小，导致DPTI/TTI比值从1.19±0.08增加到1.78±0.16（P<0.05）。在试验接近尾声时，左旋支冠状动脉平均血流量仅略有下降（5.1±9.0毫升/分钟；P<0.05），随着舒张期末期冠状动脉阻力下降31%（P<0.01），收缩期左旋支冠状动脉每搏血流量增加了116%（P<0.01）。冠状静脉平均血氧压力短暂升高，从21±1毫米汞柱升至24±2毫米汞柱，高于对照值（P<0.05）。这些数据表明，在麻醉犬中，短时间的高胸腔内压力会突然降低心肌需氧量的决定因素，而心肌灌注减少的程度较小。
