It is important to assess cardiac preload for management of patients undergoing off pump coronary artery bypass surgery (OPCAB). Recently, several studies have documented the good correlation between right ventricular end-diastolic volume index (RVEDVI) and stroke volume index (SVI), compared with cardiac filling pressures. However, none of these studies have evaluated relationship between predictors of preload and SVI measured with volumetric pulmonary artery catheter during OPCAB. The correlation of continuous RVEDVI and SVI measured with volumetric pulmonary artery catheter during OPCAB was evaluated in this study

Fifty three patients undergoing OPCAB were included. Hemodynamic parameters were measured 10 min after induction (T1), 10 min after Y-graft formation started (T2) and 10 min after sternum closure (T3). The correlation of parameters were assessed by simple linear regression.

Central venous pressure (CVP) and pulmonary artery occlusion pressure (PAOP) did not correlate with SVI during OPCAB. On the other hand, a statistically significant result was found between RVEDVI and SVI at T2 (r² = 0.133, P = 0.007) and T3 (r² = 0.380, P < 0.000). But RVEDVI and SVI were weakly correlated. And at T1, RVEDVI and SVI did not correlate.

RVEDVI is a more reliable predictor of preload compared to CVP and PAOP during OPCAB. But in post-induction period (T2), RVEDVI did not correlate with SVI.