The effect of dexmedetomidine infusion which added to total intravenous anesthesia to QT interval and QT dispersion

THE EFFECT OF DEXMEDETOMIDINE INFUSION WHICHADDED TOTOTAL INTRAVENOUS ANESTHESIA TO QT INTERVAL AND QTDISPERSIONDr. Sonay AÇIKSÖZ NANSUMMARYThe aim of this study was, to investigate the effect on QT, QTc, QTd, haemodynamicfor dexmedetomidine which was used with TIVA of propofol-remifentanil with BIS for thepatients undergoing lomber discectomy and the effect on the requirement of anesthesia andrecovery in peroperative period.Patients were divided into two groups of Group D and Group K randomly withoutpremedication. Dexmedetomidine 0.1 µg kg-1 was given for 10 min to Group D and SF wasgiven with the same doses to Group K for 10 min before the anesthesia. ThenDexmedetomidine 0.2 µg kg-1 h-1was begun and was administrated with infusion to Group Dand SF was administrated with the same doses and rate to Group K. Propofol 1 mg kg-1 ivbolus was given and was added 10 mg since BIS ≤ 65. After remifentanil bolus of 0.5 mg kg-1iv, contemporary remifentanil 0.1 µg kg-1 min-1, propofol 8 mg kg-1 h-1 infusion andvecuronium 0.1 mg kg-1 was administrated to all patients. After the extubation patients wereobserved for 1 hour in the recovery room. The value of KAH, OAB, BIS, QT, QTc, QTd,sedation scores, VNS, recovery parameters and total anesthesic doses were recorded.In the dexmedetomidine group, KAH and OAB values were significiantly lower than thecontrol group in the first 10 min after infusion and 1 min after entubation. OAB values weresignificiantly lower than control group after the first 10 min of infusion, 1 min after infusionand 1 min after the extubation. In the dexmedetomidine group QT was significiantly longerthan basal values in the first 10 minutes after infusion, at the 5. and 30. minutes of operationand at the end of the operation. In the control group, all the QT values were longer than thebasal values except the first 10 minutes after infusion and there were no differences betweenthe groups. In the dexmedetomidine group QTc were shorter than the basal values in the first10 min after infusion, at the 5. 15. 30. min of operation and in the control group QTc valueswere significiantly shorter than the basal values at 5. 30. min of operation. There were nodifferences between the group. QTd was in the normal limits for all records in the both twogroups and there were no differences between the groups. The postoperative recovery valueswere significiantly lower in the dexmedetomidine group. VNS values were lower than basalvalues in the first 10 min after infusion, at the 5., 15.,30 min in the recovery room in thedexmedetomidine group and VNS was lower than the basal values at the postoperative 5., 15.and 30 min in the control group. In the dexmedetomidine group, VNS values were lower thanthe contol group at postoperative 5., 15., 30 min. In the dexmedetomidine group sedationscores were higher than the control group for all records. In the dexmedetomidine grouppropofol doses for anesthesia induction and total propofole doses were lower than the controlgroup.Dexmedetomidine may decreases the doses of general anesthesics and is considered asantidysrthymogenic agent because of elongation effect on QT, shortening effect on QTc,inefficiancy on QTd that these parameters are known as the sign of dysrhythmia definition;and is considered as a significant component of general anesthesic administration whenadequate volume replacement is done.