The utility of intra-operative three-dimensional transoesophageal echocardiography for dynamic measurement of stroke volume

Measurement of left ventricular stroke volume and cardiac output is very important for managing haemodynamically unstable or critically ill patients. The aims of this study were to compare stroke volume measured by three-dimensional transoesophageal echocardiography with stroke volume measured using a pulmonary artery catheter, and to examine the ability of three-dimensional transoesophageal echocardiography to track stroke volume changes induced by haemodynamic interventions. This study included 40 cardiac surgery patients. Haemodynamic variables were measured before and 2min after haemodynamic interventions, which consisted of phenylephrine 100g or ephedrine 5mg. We used Bland-Altman analysis to assess the agreement between the stroke volume measured by three-dimensional transoesophageal echocardiography and by the pulmonary artery catheter. Polar-plot and 4-quadrant plot analyses were used to assess the trending ability of three-dimensional transoesophageal echocardiography compared with the pulmonary artery catheter. Bias and percentage error were -1.2ml and 20%, respectively. The concordance rate in the 4-quadrant analysis after phenylephrine and ephedrine administration was 75% and 84%, respectively. In the polar-plot analysis, the angular concordance rate was 66% and 73% after phenylephrine and ephedrine administration, respectively. Three-dimensional transoesophageal echocardiography was clinically acceptable for measuring stroke volume; however, it was not sufficiently reliable for tracking stroke volume changes after haemodynamic interventions.