Nomura K, Kurosawa H, Morita K, Okuyama H, Koyanagi K, Nagahori R, Suzuki H
Department of Cardiovascular Surgery, Jikei University School of Medicine, Tokyo, Japan.
Nihon Kyobu Geka Gakkai Zasshi. 1997 Jan;45(1):37-41.
A left ventricular pressure volume loop (PV loop) is useful not only in evaluating cardiac function, but also in predicting the postoperative hemodynamic state. There are two methods available for the intraoperative measurement of a PV loop: a conductance catheter and two-dimensional echocardiography. Although the accuracy of conductance catheter is well established for the measurement of ventricular volume, however, the accuracy of echocardiography remains controversy. This paper describes the relationship of parameters including volumes and Emax calculated with each method. Six patients who underwent open heart surgery were included in this study. Comparison of the absolute volumes at four points at the corners of the PV loop showed a Pearson's correlation coefficient of 0.62 (p-value < 0.01). In comparison with the relative volumes at four points which reflect the preoperative to postoperative change ratio, the correlation coefficient was 0.74 (p < 0.01). The correlation coefficients were 0.76 (p = 0.16) and 0.63 (p = 0.29) for the ratio of the end-diastolic and end-systolic volume respectively. Each preload-varying "Emax: out" (r = 0.84, p < 0.01) were highly correlated. As a predictor of cardiac oxygen consumption, each PVA (r = 0.84, p < 0.01) was highly correlated. We conclude that the measurement of left ventricular volume using two-dimensional echocardiography is as reliable as the conductance catheter.
左心室压力-容积环（PV环）不仅有助于评估心脏功能，还可用于预测术后血流动力学状态。术中测量PV环有两种方法：电导导管法和二维超声心动图法。尽管电导导管在测量心室容积方面的准确性已得到充分证实，然而，超声心动图的准确性仍存在争议。本文描述了用每种方法计算的包括容积和Emax在内的参数之间的关系。本研究纳入了6例接受心脏直视手术的患者。PV环四个角点处绝对容积的比较显示皮尔逊相关系数为0.62（p值<0.01）。与反映术前至术后变化率的四个点处的相对容积相比，相关系数为0.74（p<0.01）。舒张末期容积与收缩末期容积之比的相关系数分别为0.76（p=0.16）和0.63（p=0.29）。每次预负荷变化时的“Emax: out”（r=0.84，p<0.01）高度相关。作为心脏氧消耗的预测指标，每次的PVA（r=0.84，p<0.01）高度相关。我们得出结论，使用二维超声心动图测量左心室容积与电导导管法一样可靠。
