The Effects Of Dexmedetomidine On Peiroperative Hemodynamics In Patients Undergoing Transsphenoidal Approach For Microsurgery Of Pituitary Adenoma

Objective: To observe the effects and the clinical significance ofdexmedetomidine on perioperative hemodynamics in patients undergoingtranssphenoidal approach for microsurgery of pituitary adenoma.Methods:60patients, ASA I or II, aged16~65years old arescheduled for the transsphenoidal approach for microsurgery of pituitaryadenoma. After the patients came into the OR, BP, ECG and SpO2wererecorded. Then they were devided into3groups randomly: thedexmedetomidine loading dose group (D1group), dexmedetomidine loadingdose+maintenance dose (D2group)and the control group (C group). Thepatients of D1group were given dexmedetomidine (4μg/ml)0.6μg/kg over15minutes intravenously as a loading dose; D2group were maintaining with0.6μg/（kg· h） after the same loading dose with D1group; and the patientsin C group were given saline at the same speed in the same time. Fentanyl3μg/kg, cisatracurium0.15mg/kg, propofol2~3mg/kg were given for theanesthesia induction. Mechanical ventilation was maintained after theintubation. Prime setting: fresh gas flow=2.0L/min, VT=8~10mL/kg, breathing rate (f)=12times/min, to keep the end tidal CO2(PETCO2) at30~40mmHg. Anesthesia was maintained with propofol (80-120μg/kg·min)and remifentanil (0.05-0.2μg/kg·min) intravenously, supplementalcisatracurium (0.03mg/kg) was used if needed. When the surgeons put into themerocel before the end of the operation, we stopped all the anestheticsinfusion, and6mg of ondansetron was intravenously administered. Specialsituation handling: if HR<50bpm, atropine will be intravenouslyadministered. When HR rises over20%of the baseline level, esmolol will begiven. When BP rises or falls over30%of the baseline level, we will increaseor decrease the anesthetics infusion to adjust to it, or vasoactive drug will beintravenously administered.Observe and record the SBP, DBP, HR of each patient at following timepoints:10min after the patient in the OR (T0), before the intubation (T1), thetime right after the intubation (T2),5min after the intubation (T3)、10minafter the intubation (T4), the time stopping all anesthetics (T5), the time rightafter the extubation (T6),5min after the extubation (T7),10min after theextubation (T8). Then we get ΔSBP, ΔDBP, ΔHR in Tx by SBP, DBP, HR atTx minusing those at T0. Record the total doses of propfol and remifentanil,operation time, recovery time, extubation time, and the SpO2at5min,10min,30min after the extubation. Then take a Ramsay sedation score and a Stewardscore of each patient at10min after the extubation.Statistical treatment is completed with SPSS17.0package. Measurement data is expressed by mean±standard (±s) deviation,comparison between groups using independent sample t-test, group comparedwith paired t test, counting data by chi-square test. P <0.05is considered asstatistical significance.Results: We intook58patients finally. There was not significantlydifference in the general information (gender proportion, age, weight) and thebasic line of SBP, DBP and HR among3groups. Compared with T0, SBP,DBP, HR in3groups decreased significantly at T1(P <0.05); SBP and DBPin group C increased significantly at T2, T3, T6~T8(P <0.05), HR increasedat T2, T3, T6, T7(P <0.05); SBP in group D1and D2increased at T2(P <0.05), HR decreased at T4, T5(P <0.05). Compared with group C, there wasno significantly difference with SBP and DBP in group D1and D2at T1(P>0.05), but SBP and DBP decreased significantly at T2, T3, T6~T8(P <0.05),HR decreased significantly at T1~T8(P <0.05); ΔSBP, ΔDBP, ΔHR in groupD1and D2decreased at T2, T3, T6~T8(P <0.05). Compared with D1, therewere no significantly difference with SBP, DBP, HR, ΔSBP, ΔDBP, ΔHR ingroup D2at all the time points (P>0.05). There was no significantlydifference with the total doses of propofol and remifentanil, the operation timeand the SpO2at5min,10min,30min after the extubation (P>0.05) among3groups. Compared with group C and D1, the recovery time and extubationtime prolonged in group D2, and Ramsay sedation score increased, Stewardscore decreased significantly (P <0.05). Compared with group C, there were no significantly difference with the recovery time, extubation time, Ramsaysedation score and Steward score in group D1(P>0.05).Conclusions: The use of dexmedetomidine in small and short-timeneurosurgery operation (transsphenoidal approach for microsurgery ofpituitary adenoma) helps decreasing cardiovascular response and keeping amore steady hemodynamics during both tracheal intubation and trachealextubation, without prolonging the recovery time, tracheal extubation timeand not affecting the quality of recovery from anesthesia.