Different Doses Of Dexmedetomidine For The Anesthesia Effect Of Meningioma Resection

Background and ObjectiveThe ideal neurosurgery anesthesia requires anesthesia induction smoothly andquickly, intraoperative sedation analgesia effect fully, hemodynamic stability. It doesnot increase the intracranial pressure and cerebral metabolism and it does not affectthe automatic adjustment function of the cerebral blood flow. The patients wake upquickly after the drug was stopped, no respiratory depression and residual drug effect,no excitement agitation and mental symptoms and no intraopertive knows in clinicalanesthesia. At present, Propofol combined with remifentanil is the common methodsin meningioma resection of all by intravenous anesthesia. But for most of theneurosurgery operation fine, stimulates strongly and has its particularity, During theoperation, the blood pressure suddenly drops will make the patient in a state of lack,autonomic adjustment can aggravate the tumor area of the brain injury, increasesdblood pressure suddenly can cause cerebral hemorrhage or cerebral edema, lightaffect operation, heavy brain hernia were life threatening. With the operation timeprolonged, the drug accumulation increased, further lead to prolonged patientsregained consciousness, cause the adverse reactions, such as anesthesia recoveryrestless again and increased the risk of intracerebral hemorrhage. Therefore,prevention and control of neurosurgery patients due to hemodynamic changes caused by noxious stimulation, maintain good sedative depth, avoid the increase ofintracranial pressure and cerebral metabolism to maintain a stable environment isparticularly important in the brain.Dexmedetomidine is a high efficiency and high selectivity2adrenergic agonist.As dexmedetomidine becomes more and more widely in clinical applications，thereare also more and more research reports about its application.But different dose ofdexmedetomidine as general adjuvant used in neurosurgery meningioma resectionanesthesia effect literatures reported little. The study plans to use its specialpharmacological and aims to CSI as anesthesia depth index, discusses different dosesof dexmedetomidine combined with propofol and remifentanil used for efficacy,safety and suitable regimen of the neurosurgery meningioma resection, providereference for clinical.Materials and methodsSixty ASA Ⅰ or Ⅱ patients of both sexes，aged18-55yr．weighing50-75kg，scheduled for elective meningioma resection were randomly assigned into3groups(n=20each): dexmedetomidine0.2μg·kg-1·h-1group (D1group) anddexmedetomidine0.5μg·kg-1·h-1group (D2group)， control group (Cgroup)．Dexmedetomidine was infused at a rate of0.2μg·kg-1·h-1and0.5μg·kg-1·h-1ingroup D1and D2,and then stop the drug respectively until40min before the end ofneurosurgery after a loading dose of0．6μg／kg was infused over15min beforegeneral anesthesia induction．Group C received the equal volume of normal saline. Inthree groups the propofol or remifentanil dosage was adjusted according to cerebralstate index (CSI)．It was maintained at40-60．Before infusion of dexmedetomidine(T0)，when tracheal intubation (T1)，when cutting the scalp (T2)，when drilling skull(T3)，when sewing the scalp (T4)，when tracheal extubation (T5) and10mins afterextubation(T6)，the mean arterial pressure （MAP）、 the heart rate（HR） and theCSI were recorded． The dosage of propofol and remifentanil， recovery ofspontaneous breathing and orientation time，extubation time，and Richmond AgitationSedation Scale score at10min after extubation were recorded．The number of sinusbradycardia and the occurrence of adverse events of anesthesia recovery period werealso recorded． Statistical processingSPSS17.0statistical software was used for data analysis. Measurement data wereexpressed as mean±standard deviation（x s）.Analysis of variance was used tocompare the repeated measurement data within group and LSD test was used tocompare between groups.Count data using chi-square test. P<0.05was consideredstatistically significant．Results1．Compared with group C and group D1，the MAP and HR of group D2inanesthesia all decreased and within the normal range，hemodynamics leveled off，statistically significant difference between the groups (p<0.05)．.2．Compared with group C, the index of CSI decreased at T1in group D1andT1-3in group D2(p<0.05)．3. Compared with group C and group D1，the dosage of propofol andremifentanil reduced，the Richmond Agitation Sedation Scale score at10min afterremoval of the endotracheal tube were decreased and the incidence of nausea andvomiting，bucking and dysphoria during anesthesia recovery period were alsodecreased in group D2(p<0.05)．4. There was no significant difference in the time for recovery of spontaneousbreathing and orientation，and extubation time between the three groups (p>0.05)．Conclusion1. Dexmedetomidine combined with propofol and remifentanil in patientsundergoing meningioma resection calm deep well，can be effective and stablehemodynamics，and the0.5μg·kg-1·h-1dose effect is superior to0.2μg·kg-1·h-1does.2. Dexmedetomidine can be effectively inhibition of endotracheal intubation andextubation stress reaction and will not affect the extubation time，reduce the dosage ofpropofol and remifentanil，reduce the incidence of adverse reactions in anesthesiarecovery．3. Infusion of dexmedetomidine at a rate of0.5μg·kg-1·h-1after a loading dose of0.6μg／kg infused before anesthesia induction, the anesthesia effect is good，butrelatively high incidence of intraoperative bradycardia.