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Objective To determine the proper dosage of fentanyl for open heart surgery performed under cardiopulmonary bypass (CPB) without aortic cross-clamping and cardioplegia.Methods Twenty-seven ASA Ⅰ -H patients (10 male, 17 female) with fairly good cardiac function (NYHA Ⅰ - Ⅱ) scheduled for surgical repair of atrioseptal defect ( ASD) or ventricular septal defect (VSD) or mitral valve replacement (MVR) were studied. Age ranged from 18 to 44 years and body weight from 35 to 58 kg. The patients were randomly divided into three fentanyl dosage groups: group Ⅰ 10?kg ; group II 30 ?g kg-1 and group Ⅲ 50 ?g kg-1. Premedication consisted of intramuscular pethidine 1-2 mg kg-1 and scopolamine 0.05-0.06 mg kg-1 . Anesthesia was induced with midazolam 0.2 mg kg-1 and fentanyl 5 ?g kg-1 . Tracheal intubation was facilitated with vecuronium 0.15 mg g-1 . The patients were mechanically ventilated (Vr 8-10 ml kg-1 ,F 10-12 bpm,FiO2 100% ). The rest of the total dose of fentanyl (5 ?g kg-1 in group I , 25 ?g kg-1 in group II , 45 ?g kg-1 in group III) was infused after induction of anesthesia until the initiation of CPB, supplemented with inhalation of 0.6 % isoflurane. During CPB propofol was infused at 5 mg kg-1 h-1 . after discontinuation of CPB, again 0.6% isoflurane was inhaled until the end of surgery. Vecuronium 0.05 mg kg was given every 25-30 min during operation. EGG, HR, BP, CVP, SpO2, PET CO2 and body temperature (naso-pharyngeal and rectal) were continuously monitored during operation. Arterial blood samples were obtained before anesthesia (T0), 5 min after tracheal intubation (T, ) , immediately after thoracotomy (T2) , immediately before CPB (T3), 15 min after CPB was initiated (T4) , 10 min after termination of CPB (T5) and 5 min after chest was closed (T6) for blood gas analyses and determination of blood electrolytes and acid-base balance and blood concentrations of glucose, ACTH, angiotensin Ⅱ (A- Ⅱ ) and cortisol. Time of emergence from anesthesia and extubation were recorded.Results The demographic data, including age and body weight, CPB time and duration of surgery were comparable among the three groups. There were no significant changes in SpO2 , PETCO2 , body temperature, blood gases and electrolytes during operation in the three groups. MAP decreased significantly during CPB. The blood glucose, ACTH, A- Ⅱ and cortisol concentrations increased significantly during and after CPB as compared with the preanesthetic baseline (T0 ) ( P
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Objective To evaluate the effect of CPB with or without cardioplegia on hemodynamics and myocardial function. Methods Thirty NYHA class III patients undergoing mitral valve replacement were randomly divided into three groups of ten each: group Ⅰ received no blood cardioplegia; group Ⅱ received tepid blood cardioplegia solution and group Ⅲ received cold blood cardioplegia solution. The patients were premedicated with pethidine 50mg and scopolamine 0.3mg. Swan-Ganz catheter was inserted via right interval jugular vein into pulmonary artery and radial artery was cannulated under local anesthesia before anesthesia. Anesthesia was induced with midazolam 0.05-0.01 mg.kg-1, fentanyl 15-20?g. kg-1 and pancuronium 0.12mg.kg-1 and maintained with fentanyl, midazolam and pancuromium. Patients in group Ⅰ received no cardioplegic solution. Ascending aorta was not cross-clamped. Body temperature was reduced to 32℃-33 ℃ (naso-pharyngeal T) . The empty heart was beating at 40-60 bmp. In group D and Ⅲ cardioplegic solution (modified St. Thomas solution) was added to blood from oxygenator (in the proportion of 1:4).In group Ⅱ body temperature was reduced to 32℃-33℃.Tepid (32℃ ) hyperkalemia blood cardioplegic solution was infused at 200-250ml.min-1 after ascending aorta was cross-clamped. After cardioplegic arrest hypokalemic blood cardioplegia solution was infused. In group Ⅲ body temperature was reduced to 28℃-29℃. Cold (8℃) hyperkalemic blood cardioplegic solution was infused at 200-250ml. min-1, after ascending aorta was cross-clamped. After cardioplegia arrest cold hypokalemic blood cardioplegia solution was infused every 20 min. Hemodynamic parameters (MAP, MPAP, CO, CI, SVRI, PVRI, LVSWI and RVSWI) were recorded before anesthesia (T0), before CPB (T1), 10, 30, 60 min after termination of CPB (T2-T4 ) and at the end of surgery (T5 ) . Results Demographic data including age, gender, body weight and body surface area were comparable between the three groups. CI in group 1 and Ⅱ was significantly higher at T2 -T5 than that in group Ⅲ . SVRI after CPB in group Ⅰ was significantly lower than that in group Ⅲ . Conclusion The myocardial function after CPB without cardioplegia is better than that after CPB with cold cardioplegia, but is not significantly different from that after CPB with tepid blood cardioplegia.