This study is to assess the effect of desflurane on myocardial function in patents who underwent coronary artery bypass grafting.

Desflurane, one of the third-generation inhaled anesthetics, is introduced in clinical practice in 1990s. Decades of clinical use has provided evidence for desflurane's safe and efficacious use as a general anesthetic. Compared with other volatile anesthestics, it has several characteristics: lower blood and lipid solubility, more stable in vitro and the lowest in vivo metabolism. Its particular low fat solubility properties promote rapid equilibration and rapid elimination at the end of anesthesia which reduces slow compartment accumulation and promotes predictable emergence, early extubation, and the ability to rapidly transfer patients from the operating room to the recovery unit. In addition, several investigations found that patients with desflurane anesthesia recovered their protective airway reflexes and awakened to a degree sufficient to minimize the stay in the high dependency recovery area.

A burgeoning body of investigations has shown that desflurane can directly act on myocardial and vascular functions. Desflurane has coronary vasodilative effects in in situ canine hearts which is comparable to sevoflurane does. Although it is controversial regarding to the effect of desflurane on myocardial excitation-contraction coupling and electrophysiologic behavior, a elaborated study found desflurane induced a positive inotropic effect in rat myocardium in vitro compared with isoflurane. A recent study suggested that desflurane decreased right ventricular contractility much less and maintained the right over left pressures ratio at more favorable values compared with sevoflurane. Furthermore, substantial investigations found that clinically relevant concentration desflurane preconditioning or postconditioning could protect myocardium from ischemia-reperfusion in mammalian animal models or isolated human cardiac tissues. However, it is unclear whether desflurane can provide protection for patients with coronary artery disease. Therefore, this study is designed to investigate the effect of desflurane on myocardial function in patents who underwent coronary artery bypass grafting.

Inclusion Criteria:

1. Diagnosed with CAD 2. ASAⅡ～Ⅲ

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Exclusion Criteria:

1. Left ventricular ejection fraction <40%
2. Left ventricular aneurysm
3. Acute myocardial infarction in latest two weeks, atrial fibrillation
4. Associated vascular diseases, severe systemic diseases involving the renal and hepatic systems
5. Respiratory disease( forced vital capacity less than 50% of predicted values )
6. Preoperative left bundle branch block -