Effects Of High Thoracic Epidural Anaesthesia On Myocardial Injury In Patients Undergoing Off-pump Coronary Artery Bypass

Objective To investigate the projective effects of high thoracic epidural anaesthesia on myocardial injury in patients undergoing off-pump coronary artery bypass grafting(OPCAB).Methods Thirty patients with coronary artery disease (18 male, 12 female) aged 48-72 years,weighing 51-80kg undergoing OPCAB were scheduled to undergo the surgical operation of OPCAB. Patients were randomly allocated to receiving either general anesthesia (group Ⅰ,n=15),or general anesthesia combined with high thoracic epidural anesthesia(HTEA)(group n,n=15).An epidural catheter was inserted at the T4.5 interspace in the patients of group Ⅱ before the operation.Before induction, a test dose of 3mL of lidocaine 2% was administered.A bolus(5-8mL) epidural infusion of lidocaine 0.8% and fentanyl 2μg·mL-1 was started until the desired anesthetic level was established at T1-7. To maintain anesthesia,continuous epidural infusion was started at the rate of 5mL·h-1.Operation was performed under general anesthesia induced with midazolam 0.05mg·kg-1, fentnyl 3-5μg·kg-1, propofol 0.5-1mg·kg-1 and vecuronium 0.15mg·kg-1 and maintained with isoflurane inhalation and propofol infusion(3-6mg·kg-1·h-1).Artery blood samples were obtained at the following time pointsrbefore operation(T1), 1h(T2),24h(T3)and 48h(T4) after operation for determination of plasma CK-MB,cTnI, ET-1 and ANP.Results Plasma CK-MB,cTnI, ET-1 and ANP in group Ⅱ were significantly lower than those in group Ⅰ 24h and 48h after operation(P<0.05) .But there was no significant difference in group Ⅱ (P>0.05).Conclusion In patients with OPCAB ,HTEA can effectively suppress the increase in plasma ET-1 and ANP,CK-MB and cTnI level.