Evaluation of the E/e' Ratio of the Mitral Annulus Measured by Transesophageal Echocardiography in Predicting Fluid Responsiveness.
Evaluation of the E/e' Ratio of the Mitral Annulus Measured by Transesophageal Echocardiography in Predicting Fluid Responsiveness.
Diastolic function may be evaluated by different measurements on transesophageal echocardiography (TEE). They include mitral inflow velocities obtained by pulsed-wave doppler (PW) : peak early diastolic velocity (E) and late diastolic velocity (A). Mitral annulus velocities, early diastolic (e') and late diastolic (a') are obtained by tissue doppler imaging (TDI). The ratio E/e' reflects left ventricular filling pressure and, as such, might be a predictor of fluid responsiveness.
The aim of this study is to evaluate the predictive value of the mitral valve E/e' ratio for fluid responsiveness among patients undergoing coronary bypass graft surgery. Fluid responsiveness being defined as an increase in stroke volume of ≥ 15%.
After induction of anesthesia, patients will have their diastolic function evaluated by means of E/e' and other measures. They will then be administered an intravenous bolus of 500 mL of Lactate Ringer® along with passive leg raising (PLR). Stroke volume and fluid responsiveness will be assessed by the thermodilution method (Swan-Ganz catheter) and the FloTrac® device. Fluid responders will be compared to non-responders to evaluate the relationship between E/e' ratio and fluid responsiveness.
Inclusion Criteria:
Exclusion Criteria: