Research Of Hemodynamic Changes And Oxygen Metabolism During Anesthesia Of Off-pump Coronary Artery Bypass Grafting

Objectives:With the development of operation technology and the improvements of the anesthetic management level, OPCABG has become one of the effective methods which is used to cure the coronary heart disease. Compared to CCABG, OPCABG has fewer affect on the internal environment of the patients and fewer complications. Because the heart keep beating during the operation period, the change of the heart location and the application of heart holder may influence hemodynamic and oxygen metabolism at different operation stage. The purpose of this study is to evaluate the anesthesia methods by observing hemodynamic changes and oxygen supply and demand balance during OPCABG in order to provide the reference for the OPCABG anesthesia management level.Methods:Thirty patients scheduled for elective OPCABG were premedicated with intramuscular scopolamine 0.3mg/kg and morphine 0.15mg 30 minutes before anesthesia. Artery blood pressure was monitored through radial artery catheter. Swan-Ganz floating catheter was placed into pulmonary artery through the right internal jugular vein and connected to Edwards LifesciencesTM Vigilance II monitor to gain hemodynamic changes and oxygen metabolism index. Anesthesia was induced with midazolam 0.05～0.1 mg/kg, sufentanil 1～2μg/kg, etomidate 0.3mg/kg, vecuronium 0.1～0.2mg/kg and maintained with propofol by target control infusion. The infusion rate of propofol was 1～4μg/(kg-min), intravenous sufentanil and atracurium was administered discontinuously. Conventional continuous intravenous nitroglycerin 3～5μg/(kg-min) and dopamine 3～8μg/(kg-min) were administered through infusion pump, adjusting the infusion speed according to the hemodynamic changes in order to maintain hemodynamic relatively stable. Hemodynamic and oxygen metabolism index was recorded respectively at preoperative (T1), after the sternal incision (T2), LAD anastomosis (T3), CX/DIA anastomosis (T4), RCA anastomosis (T5) and the end of the operation(T6).Results:The preload parameters change significantly at T4and T5. Compared to T1, CVP and RVEDV decrease significantly (P<0.05) at T4. PCWP increase significantly (P<0.05) at T5. The afterload parameters change at T3 and T5.SVR and SVRI decrease significantly (P<0.01) at T3. SVRI decrease significantly (P<0.05) at T5. The cardiac systolic function was mainly influenced at T3, T4 and T5. Compared to T1, RVEF, CCO and CCI increase significantly (P<0.05) at T3, SV and SVI decreased significantly (P<0.01) at T4, RVEF increase significantly (P<0.05) at T5. The pressure related parameters change at T4 and T5. CVP decrease significantly (P<0.05) at T4, PCWP increase significantly (P<0.05) at T5. Oxygen supply and demand balance parameters change at T2, T3, T4 and T5. O2ER and O2EI decrease significantly (P<0.01), Ca-vO2 decrease significantly (P<0.05) at T2. SvO2 increase significantly (P