The Comparisons Of The Effects On Hemodynamics And Oxygen Balance Induced By Gamma-hydroxybutyrate, Midazolm And Etomidate In The Patients During Coronary Artery Bypass Grafting Surgery

ObjectiveTo investigate the effects of gamma - hydroxybutyrate ( GHB) , midazolam and etomidate on haemodynamic and oxygen balance in patients undergoing coronary artery bypass surgery.Methods45 cases, ASA M ~ IV, undergoing coronary artery bypass grafting (CABG) were randomly allocated into 3 groups. Each group consists of 15 cases. They were gamma - hydroxybutyrate ( GHB, group G) , midazolam ( group M) and etomidate (group E). Anesthesia was induced with one of the following agents: GHB ( 60 mg kg-1) , midazolam (0.2 mg kg-1) or etomidate (0.3 mg kg-1) respectively in combination with fentanyl (10ug kg-1) and pipecuronium bromide (0. 08 mg kg-1). After endotracheal intubation, anesthesia was maintained with fentanyl and isoflurane for all patients. Haemodynam-ics were measured using conventional monitor including EGG, HR, SBP, DBF, MAP, CVP, PAWP, and oxygen balance measurements were performed using CCO/Sv02 Swan - Ganz catheter. All the data were collected in the following time sequences: pre - induction period ( T0 ) , post - induction period (T1) , 3 minutes after intubation ( T2) ,incision period ( T3) and before CPB period ( T4 ). All the data were analysed using analysis of variance ( ANOVA) and p <0.05 was considered as significant. Results patients' age, body weight, sex and premedication were comparable among the three groups. All CABG was successessfully performed under the present anesthesia regimen without any complication associated with anesthesia. After induction of anesthesia, heart rate was increased up to pre CPB period in group G and the same trend was demonstrated in group E, but it remained unchanged in group M. The MAP was reduced in all groups, but it was only significant in group G after induction of anesthesia. CVP was significantly elevated in group E and PAWP remained stable in all groups. CI, LVSWI and RVSWI were reduced after induction of anesthesia in group G and group M, but remained unchanged in group E. DO21 was reduced up to pre - CPB period after induction of anesthesia in group G. However, DO2I was augmented in group M after induction and reduced after intubation. It remained unchanged in group E. V02 I was reduced in all groups, especially in group G ( P < 0.05 ). SVRI was reduced in group M (P <0.05) and same trend was found in other groups. PVRI was decreased after induction of anesthesia but elevated after intubation in group G. It remained low values after induction in group M and group E. No changes of S - T segments of EGG were detected and no inotropics was utilized during anesthesia due to hemodynamics reasonably stable.ConclusionsGHB, midazolam and etomidate are suitable anesthetic agents for the patients undergoing CABG procedures. They kept reasonable depth of anesthesia without comprimased hemodynamics. Etomidatekept hemodynamics more stable than those of others. GHBA reduced VO2I more obviously than DO2I. This is a definitely benefit for the patients undergoing CABG during anesthesia.