Abstract
The aim of this study was to validate measurements of intraoperative left ventricular (LV) area by transoesophageal echocardiography against simultaneous measurements of LV volume by conductance catheter (CC) in cardiac surgical patients with normal systolic LV function. Echo area was compared with CC volume during steady state and during acute changes of pre‐ and afterload by partial clamping of the inferior vena cava and the ascending aorta in eight patients scheduled for coronary artery bypass grafting. At steady state, Bland-Altman analysis of 32 recordings revealed a bias (sd) of 0.6% (2.5%) between echo area and CC volume, related to the initial values of end‐diastolic area (100% area) and volume (100% volume), respectively. During loading interventions, bias between the two methods, as assessed by 112 measurement sequences, was 0.5% (3.7%) during aortic occlusion and -3.9% (4.4%) during cava occlusion at end‐systole (P<0.0001); at end‐diastole, this bias was 1.3% (4%) during aortic occlusion and 0.2% (5.7%) during cava occlusion (P<0.0001). Intraoperative area measurements with transoesophageal echocardiography in cardiac surgical patients with normal systolic LV function show good correlation with CC volume measurements under steady‐state conditions. During acute unloading by vena cava occlusion, the resulting small end‐systolic echo area measurements differ significantly more from CC volume measurements than during acute increase in afterload by aortic occlusion. Br J Anaesth 2000; 85: 379-88
Schmidlin, D