The Observation Of Anesthetic Effect For Small Doses Of Dexmedetomidine And Remifentanil On Off-pump Coronary Artery Bypass Surgery

Objective: Through the contrast of anesthetic effect between small doses of dexmedetomidine and remifentanil were complex on off-pump coronary artery bypass operation, To observe the effect of dexmedetomidine of hemodynamics, anesthetic effect during operation,and also explore the effect of dexmedetomidine in the off-pump coronary artery bypass grafting operation.Methods: 100 patients who had performed off-pump coronary artery bypass surgery were selected in the Second Hospital of Hebei Medical University in August 2013 to December 2014. All the patients were randomly divided into D group(n=50, dexmedetomidine group) and R group(n=50, remifentanil group).Patients need fasting and water-deprivation for 6- 8h. The night before surgery, all the patients need take Diazepam Orally with 0.08-0.15mg/kg, and an hour before surgery they also need take Diazepam with 0.08-0.15mg/kg and Metoprolol Tartrate with 12.5-50.0mg dose orally,30 minutes before surgery,they need Morphine Hydrochloride with 0.2mg/Kg dose and Scopolamine Hydrobromide with 0.3mg by intramuscular injection. After patients entered the operation room,they should be kept warm first.Then after the disinfection of the left hand with the surgical isolator,they would be taken paracentesis of the left radial artery under local anesthesia. Patients need take intravenous vecuronium with 0.1mg/kg dose, etomidate with 0.15-0.3mg/kg dose, fentanyl with 8-10ug/kg dose, midazolam with 0.1-0.2mg/kg dose,and dexamethasone with 10 mg dose during anesthesia induction. After that, they would be masked plus pressure oxygen until they lost conscious(containing eyelash reflex), muscle relaxation. After taking endotracheal intubation and connected to ventilator, we set the respiratory parameters: oxygen flow of 2L/min, tidal volume of 8-12 ml/kg, breathe frequency 10 to 12 times/min, end-tidal CO2 within the normal range(35-45 mm Hg). Then adjusting the position with Trendelenburg, we disinfected the neck skin and take paracentesis of the right internal jugular vein with double-lumen internal jugular vein catheter placement. At last,they had been carried out blood-gas analysis before the start of surgery.In Group D, we maintained anesthesia with intravenous infusion of dexmedetomidine with 0.1-0.3μg?kg-1?h-1 dose and inhalation of sevoflurane with 0.58-1.76 MAC, ensure the requirements of muscle relaxation with intermittent chasing vecuronium and remaine pulse oxygen saturation above 98%. When transferred the patient after surgery to the cardiac surgery ICU, we continued give the infusion of dexmedetomidine with 0.1μg?kg-1?h-1dose.In Group R, we maintained anesthesia with intravenous infusion of remifentanil with 0.1-0.2μg?kg-1?min-1 dose and inhalation sevoflurane with 0.58-1.76 MAC and maintain the requirements of muscle relaxation with giving injections of vecuronium continuously. When transferred the patient after surgery to the cardiac surgery ICU, the patients had been kept giving the infusion of remifentanil with 0.05μg?kg-1?min-1 dose.Vasoactive drugs, such as ephedrine, norepinephrine which are in order to maintain the heart rate, blood pressure stable, may be administered during surgery as necessary as possible. We adjusted the rate of infusion according to the bleeding. By adjusting inhalation of sevoflurane, the BIS value was maintained at 40 to 60. According to the heart rate, blood pressure and other conditions, then they had adjusted the rate of remifentanil, dexmedetomidine to maintain the heart rate, blood pressure steadily and to reduce operation stimulation.Electrocardiogram(ECG), heart rate(HR), invasive systolic(SBP), diastolic blood pressure(DBP), mean arterial pressure(MAP), pulse oxygen saturation(Sp O2) and end-expiratory carbon dioxide partial pressure(Pet CO2), the depth of anesthesia monitoring(BIS), central venous pressure(CVP), nasopharyngeal temperature, monitoring end-tidal carbon dioxide monitoring(et CO2), intermittent monitoring of blood gases, the observation of urine were showed in the Multifunction anesthesia monitor. All the patients would had observed and recorded the index of patients of two groups:1 The heart rate(HR), mean arterial pressure(MAP), systolic blood pressure(SBP) and diastolic blood pressure(DBP) were recorded before induction of anesthesia(T0), before skin incision(T1), in skin incision(T2), in cutting sternum(T3), in bridging anterior descending artery(T4), in bridging right coronary branch(T5), in bridging the circumflex artery(T6), in bridging the diagonal branches(T7), leaving the operating room(T8),and entering the ICU of Cardiac Surgery(T9). The depth of anesthesia(BIS) values was recorded at T1, T2, T3, T4, T5, T6, and T7.2 The duration of anesthesia and operation, dose of vasoactive drugs and furosemidum were recorded during the operation.3 The lactate values of arterial blood was recorded before operation, during operation and after operation.4 The length of awake time, extubation time and ICU stay in two groups of patients were recorded.5 Whether there were complications in the patients were anesthetized in off-pump coronary artery bypass grafting operation would be recorded(Postoperative pain, restlessness, nausea, vomiting and intraoperative recall).Results:1 The general condition of the selected patient100 cases of patients in all had experienced off-pump coronary artery bypass grafting operation, and male accounted for 81 cases(81%), female accounted for 19 cases(19%), hypertension patients accounted for 66 cases before surgery(66%), diabetic patients accounted for 18 cases(18 %), remote infarct accounted for 28 cases(28%), chronic cerebral infarction accounted for 10 patients(10%). All patients were grade for ASA classification, and class ⅣIII for heart function.Mean age was 60 ± 9 years and mean left ventricular size was 52 ± 5mm, mean EF(ejection fraction heart) was 60 ± 4%.2 General comparison of two groupsThere were not statistical significance between two groups in the age, weight, gender, preoperative comorbidities(hypertension, diabetes, myocardial infarction, cerebral infarction), ejection fraction, left ventricular size, MAP before operation, HR before operation, the duration of surgery, the duration of anesthesia, the amount of liquid crystal, the amount of colloid and urine output(P>0.05).3 The amount of vasoactive drugsThere were not statistical significance between two groups in total dose of vasoactive drugs(ephedrine, noradrenaline)(P>0.05).4 The length of awake time, extubation time and ICU stay timeThere were statistical significance between two groups in the length of awake time, extubation time and ICU stay, and Group D was shorter than Group R(P<0.05).5 The change of Lactate value between two groupsDuring operation, there were statistical significance between two groups in Lactate value,and Group D was lower than Group R.(P<0.05). Before and after operation, there were not statistical significance between two groups in Lactate value.6 The changes of blood pressure, heart rate and hemodynamics during the operation.In dexmedetomidine group,there were not statistical significance between T2 and T1 in HR,and the difference was also not exist between T3 and T1,T5 and T4,T8 and T9(P>0.05).In Remifentanil group, there were statistical significance between T2 and T1 in HR,and the difference was also exist between T3 and T1, T8 and T9(P <0.05).At T2, T3, T4, T5, T6, T7, T8 and T9, there were statistical significance betweem two groups in HR, and Rroup R was higher than Group D(p<0.05). At T0, T1, there were not significance betweem two groups in HR(p>0.05).In Dexmedetomidine group, there were not statistical significance between T2 and T1 in MAP, and the difference was also not exist between T3 and T1,T8 and T9(P>0.05).In Remifentanil group, there were statistical significance between T2 and T1 in MAP,and T2 was higher than T1. The difference was also exist between T3 and T1,T8 and T9(P <0.05).At T2, T3, T4, T5, T6, T7, T8 and T9, there were statistical significance betweem two groups in MAP, and Rroup R was higher than Group D(P<0.05). At T0, T1, there were not significance betweem two groups in MAP(P>0.05).7 BIS valuesAt T3, T4, T5, T6, there were statistical significance betweem two groups in BIS value,and Group D was higher than Group R(P<0.05). At T0, T1, T2, T7, there were not statistical significance betweem two groups in BIS value(P>0.05).8 There were not statistical significance in complications after anesthesia(irritability, pain, nausea, vomiting, and intraoperative awareness etc).Conclusions:1 In the off-pump coronary artery bypass operation, dexmedetomidine combined with sevoflurane, which is better than remifentanil combined with sevoflurane during anesthesia, can maintain the stability of hemodynamics, improve minicirculation, have a diuretic effect and reduce the length of awake time, extubation time and ICU stay.2 During patients experienced off-pump coronary artery bypass operation were transported to ICU, Dexmedetomidine can decrease the fluctuations of blood pressure and heart rate.3 Using Dexmedetomidine could control the excitability of cardiac muscle in the off-pump coronary artery bypass operation. BIS should be noticed.