Patients undergoing scheduled surgical procedures requiring general anesthesia and invasive arterial pressure and advanced cardiac function monitoring. A trans thoracic ultrasound examination of cardiac function will be performed before induction of general anesthesia . In the operating room, the anesthesia care team will place all of the standard intra-operative monitors and then induce general anesthesia. After induction, the ultrasound examination will be repeated and the planned additional intra-operative monitors will be placed. The arterial catheter will be attached to a FloTrac/EV1000 monitor that will be used to guide fluid management during the procedure. The sensitivity and specificity of SVV to predict the response of cardiac output to intravenous fluid administration will be assessed in this patient group distinguished by their normal left ventricular diastolic function.

Patients undergoing scheduled surgical procedures requiring general anesthesia and invasive arterial pressure and advanced cardiac function monitoring. A trans thoracic ultrasound examination of cardiac function will be performed before induction of general anesthesia . In the operating room, the anesthesia care team will place all of the standard intra-operative monitors and then induce general anesthesia. After induction, the ultrasound examination will be repeated and the planned additional intra-operative monitors will be placed. The arterial catheter will be attached to a FloTrac/EV1000 monitor that will be used to guide fluid management during the procedure. The sensitivity and specificity of SVV to predict the response of cardiac output to intravenous fluid administration will be assessed in this patient group distinguished by their abnormal left ventricular diastolic function.

Ultrasound examination of cardiac function before and after induction of general anesthesia.

The sensitivity of SVV as a predictor of the change in cardiac output in response to IV fluid administration will be determined by analysis of the Receiver Operator Characteristic (ROC) curves for each of the patient groups as distinguished by their pre-induction assessment of diastolic left ventricular function

Transthoracic ultrasound will be performed before and after the induction of general anesthesia to assess left ventricular diastolic function. Measurements of trans-mitral flow velocities and tissue Doppler velocities will be used to establish the grade of left ventricular diastolic function. The reproducibility of this measurement before and after the induction of anesthesia has ramifications for intra-operative measurement of diastolic function.