Chitwood W R, Hill R C, Sink J D, Kleinman L H, Sabiston D C, Wechsler A S
J Thorac Cardiovasc Surg. 1980 Nov;80(5):724-35.
In these studies, we evaluated the applicability of pulse-transit sonomicrometry for measuring changes in global cardiac activity in patients during cardiac operative procedures. In six patients two epicardial ultrasonic crystals (8 mm) were sutured across the left ventricular minor axis. Diastolic pressure-length data were recorded as left ventricles were filled passively to transmural pressures (P) from 0 to 20 mm Hg. Data were collected at the beginning of cardiopulmonary bypass and again 15 minutes following periods of induced global ischemia (29.8 +/- 0.8 minutes). Minor axis length data were normalized to Lagrangian strain (epsilon), and best-fit regression curves were obtained from P-epsilon by computer analysis. Nonlinear elastic constants, alpha and beta, were mathematically derived as additional curve descriptors. Decreases in ventricular compliance were demonstrated as leftward shifts in both computed and measured P-epsilon curves. Global ischemia appeared to effect a decrease in overall ventricular diastolic compliance in all patients studied (p =7E 0.01 at 5, 10, 15, 20 mm Hg). Simultaneously, no statistical change occurred in lo (62.93 +/- 2.80 mm), which represented end-diastolic length (EDL) at 0 mm Hg transmural pressure. Following coronary grafting several patients showed augmented systolic excursion when compared at similar EDL. For those analyses, shortening was compared at specific minor axis EDLs rather than filling pressures. These data indicate that experimentally developed sonomicrometry may safely provide accurate indices of systolic and diastolic ventricular properties during operations necessitating cardiopulmonary bypass. Thus various cardioplegic solutions, ischemic arrest periods, and inotropic agents may be evaluated more objectively.
在这些研究中，我们评估了脉冲传输超声微测技术在心脏手术过程中测量患者整体心脏活动变化的适用性。在6例患者中，将两个心外膜超声晶体（8毫米）跨左心室短轴缝合。当左心室被动充盈至跨壁压力（P）从0至20毫米汞柱时，记录舒张期压力-长度数据。在体外循环开始时以及诱导性整体缺血（29.8±0.8分钟）15分钟后再次收集数据。短轴长度数据被归一化为拉格朗日应变（ε），并通过计算机分析从P-ε获得最佳拟合回归曲线。非线性弹性常数α和β通过数学方法推导得出，作为额外的曲线描述符。心室顺应性降低表现为计算和测量的P-ε曲线均向左移位。在所有研究患者中，整体缺血似乎导致心室舒张期整体顺应性降低（在5、10、15、20毫米汞柱时p = 0.01）。同时，代表跨壁压力为0毫米汞柱时舒张末期长度（EDL）的lo（62.93±2.80毫米）无统计学变化。冠状动脉移植术后，与相似的EDL相比，部分患者收缩期偏移增加。对于这些分析，在特定的短轴EDL而非充盈压力下比较缩短情况。这些数据表明，实验开发的超声微测技术在需要体外循环的手术过程中可安全地提供准确的心室收缩和舒张特性指标。因此，可以更客观地评估各种心脏停搏液、缺血停搏时间和正性肌力药物。
