The Clinical Application Of Dexmedetomidine In Functional Neurosurgery Operation

Part one The sedative effect of Dexmedetomidine in anesthesia during epilepsy operationObjectiveTo observe the sedative effect and adverse reaction of Dexmedetomidine in anesthesia during epilepsy operation.MethodsThirty epilepsy patients (ASAⅠ-Ⅱ) were randomly assigned into two groups (n=15 for each group), including Dexmedetomidine group (Group D) and control group (Group C). In Group D, a loading dose of 1μg/kg Dexmedetomidine was slowly injected in 10 minutes, followed by 0.4μg/kg/h Dexmedetomidine maintained until the end of surgery. In Group C, 0.9% normal saline were given as control. In two groups, inhaling sevoflurane with concentrations of 1-3% and pumping propofol and remifentanil maintain anesthesia. The HR, MAP, RR, SPO2, OAA/S scale, Ramesay scale were monitored, and intraoperative hemodynamics abnormalities, dose of propofol and remifentanil, time of spontaneously breathing recovery, awakening, consciousness and extubation, adverse reaction were recorded. The above parameters were continuous recorded at the time points of pre-infusion Dexmedetomidine(T0), after loading dose(T1), 10 minutes after loading dose(T2), after induction and before intubation(T3), after intubation(T4), before incising skin(T5), 2 minutes after incising skin(T6), awakening(T7), afer extubation(T8).Results1. There was no significant difference in general state of health among two groups, including sex ratio, age, ASA grade, body weight.2. After loading dose of Dexmedetomidine was given and during maintain continuous infusion, doses of propofol and remifentanil and OAA/S scale obviously decreased(P<0.05); Ramesay scale stepped up significantly (P<0.05), which showed the obvious sedative effects.3. HR of patients in Group D obviously decreased (P<0.05) compared with basal value, MAP descend (P>0.05); there was no respiratory depression.4. Time of breathing recovery, awakening, consciousness and extubation in Group D was short compared with Group C, but there was no significant difference between two groups (P>0.05).5. Incidence rate of adverse reaction in two groups was very low, there was no obvious difference between two groups (P>0.05). ConclusionAfter loading dose of Dexmedetomidine was given and during maintain continuous infusion, there was evident sedative effect, doses of propofol and remifentanil obviously decreased, there was no severe harmful incidence, which showed satisfactory safety.Part two The effect of Dexmedetomidine on electrocorticography in epilepsy lumpectomyObjectiveThe present study was to evaluate the effect of continuing infusion Dexmedetomidine on electrocorticography in epilepsy lumpectomy.MethodsSixty epilepsy patients (ASAⅠ-Ⅱ) were randomly assigned into four groups, including Group A,B,C and D, n=15 for each group. A loading dose of 1μg/kg Dexmedetomidine was slowly injected in 10 minutes for all patients. Then anesthesia was induced with propofol 2mg/kg, fentanyl 3μg/kg, vecuronium 0.1mg/kg and maintained with sevoflurane, remifentanil and Dexmedetomidine. The patients were mechanically ventilated after tracheal intubation with the parameters as follows: VT 8-10ml/kg, RR 12 bpm, I:E 1:1.5. The pressure of End-tidal CO2 was maintained at 30-35mmHg. The maintenance dose of Dexmedetomidine is: 0.2μg/kg/h in Group A, 0.4μg/kg/h in Group B, 0.6μg/kg/h in Group C and 0.8μg/kg/h in Group D respectively. For all patients, the electrocorticography is monitored to locate focus of epilepsy for all patients. All drugs were stopped (except of vecuronium) when electrocorticography is begin monitored. Time of drug discontinuance to electrocorticography location was recorded. Intraoperative electrocorticography waveform was recorded, amplitude and frequency of waves were measured.Results1. There was no significant difference in general state of health among four groups ( sex ratio, age, body height, body weight ).2. Compared with Group A, the time of drug discontinuance to electrocorticography location clearly in Group B and Group C extended, but there was no significant difference. However the time of waiting in Group D obviously extended, there was significant difference compared with Group A.3. Classification of electrocorticography, especially numbers and ratio of grossly abnormality in Group B and Group C were very similar with Group A. But there was obviously difference in electrocorticography classification between Group D and Group A, numbers and ratio of grossly abnormality obviously decreased in Group D.4. In four groups, there was spike wave in electrocorticography. Frequency of spike wave in electrocorticography gradually decreased when dose of Dexmedetomidine increased, but there was no significant difference (P>0.05). Amplitude of spike wave in electrocorticography has not markedly changed in four groups.ConclusionSuitable dose range of Dexmedetomidine in maintenance process of anesthesia is 0.2-0.4μg/kg/h in epilepsy lumpectomy, this dose doesn't induce depressed electrocorticography, therefore it doesn't effect the location of focus of epilepsy.