Effect of Desflurane on Cardiac Function During Cardiac Surgery: Tissue Doppler Imaging of Mitral Valve Annular Velocity

Effect of Desflurane on Cardiac Function During Cardiac Surgery: Tissue Doppler Imaging of Mitral Valve Annular Velocity

Effect of Desflurane on Left Ventricular Function in Remifentanil-based Anesthesia for Cardiac Surgery: Tissue Doppler Imaging of Mitral Valve Annular Velocity

The purpose of this study is to determine desflurane's dose-dependent effect on left ventricular (LV) function in cardiac surgery. The change of tissue Doppler imaging (TDI) of lateral mitral valve annular velocity at three different desflurane concentrations would be analyzed by using intraoperative transesophageal echocardiography (TEE) in cardiac surgery patients

Tissue Doppler imaging (TDI ) of mitral annular velocity during the cardiac cycle has been introduced as a reliable method for analysis of systolic and diastolic LV ling-axix function , efficacy of diastolic TDI profile, including early early relaxation (E') and atrial contraction (A') and has been suggested to be useful in predicting the postoperative clinical outcomes and the impact of isoflurane on LV diastolic function. Desflurane is widely used in cardiac surgery patients due to its beneficial effects , but many studies have shown that desflurane reduces myocardial contractility in a dose-dependent manner, and compromises left ventricular( LV) function We hypothesized that desflurane , even at a clinical dosage, would affects intraoperative LV systolic function in a dose-dependent manner and thus produce significant changes int the TDI profiles of mitral annular velocity. So we planned to study the changes in TDI profiles of lateral mitral annular velocity at the clinical desflurane dosage during remifentanil based anesthesia for cardiac surgery

After achieving stable hemodynamics and BIS 40-60 with desflurnae 0.5 MAC and remifentanil 0.7-1.0 mcg/kg/min (T1), data including S', E', A', EF, E, A and BIS are determined. After 10 min exposure to the increased desflurane dosage 1.0 MAC (T2), data are determiend. After 10 min exposure to the increased desflurane dosage 1.5 MAC (T3), data are determined. Reduction of BP is managed by the increment of phenylephrine infusion

Peak systolic mitral annular velocity (S') using tissue Doppler imaging By using pulsed Doppler with the sample volume positioned at the lateral mitral valve (MV)ring in the midesophageal 4-chamber view, S' would be determined just after the 10 min-exposure to each concentration of desflurane, 0.5 MAC, 1.0 MAC and 1.5 MAC (T1, T2 and T3, respectively)

Peak mitral annular velocity during early diastole (E'): By using pulsed Doppler with the sample volume positioned at the lateral MV ring in the midesophageal 4-chamber view, Peak mitral annular velocity during atrial contraction(A'): By using pulsed Doppler with the sample volume positioned at the lateral MV ring in the midesophageal 4-chamber view, ejection fraction (EF): By using modified Simpson technique in the midesophageal 4-chamber view, bispectral index (BIS) peak velocity of mitral inflow during early relaxation (E): By using pulsed Doppler with the sample volume positioned at the IMV opening in the midesophageal 4-chamber view, peak velocity of mitral inflow during atrial contraction (A): By using pulsed Doppler with the sample volume positioned at the tip of MV opening in the midesophageal 4-chamber view,

Ages eligible for study : 20 years to 65 years Genders eligible for study : Both Inclusion Criteria: Patients undergoing cardiac surgery Exclusion Criteria: Low ejection fraction <50% in preoperative transthoracic echocardiography Atrial fibrillation Pacemaker Pericardial and infiltrative myocardial disease Mitral annular calcification, surgical rings, prosthetic mitral valves Lateral left ventricular regional wall motion abnormality Esophageal spasm, stricture, laceration, perforation, and diverticulum Diaphragmatic hernia History of extensive radiation to mediastinum Upper gastrointestinal bleeding