Effects Of Remifentanil On Children’s QT Interval During General Anesthesia Induction Period By Sevoflurane

Sevoflurane is a new inhalation anesthetic, which has been widespread used in general anesthesia due to its unique phamacokinetic profile, such as fast induction, fast palinesthesia, no stimulate smell, little effects on the respiration and cardiovascular system. Trachea cannula by inhaling high concentration sevoflurane without muscle relaxant has been a main anesthesia method to children. Remifentanil is a new μ-recepter agonist, which has been an opioid of21st century due to its fast effect and quick clearnce quickly and good controllability.QT interval is the time from the beginning of QRS-wave to the end of T-wave, which represents the period from ventricular depolarization to repolarization. Every risk factors of QT interval can induct the TdP, which has evoked wide attention. The effects of remifentanil on children’s QT interval during general anesthesia induction period by sevoflurane has seldom been reported.The effects of remifentanil on children’s QTc and hemodynamics was studied due to tracheal intubation by sevoflurane induction. The article compared the effects of remifentanil(different doses) on children’s QTc and hemodynamics and aimed to explore the optimal dose of remifentanil. And a more secure anaesthesia method for children was to be sought. Sixty patients(male, ASA I, aged (3-6)y, weight(14-25)kg) planned to operate by tracheal intubation, were randomly divided into three groups. Group S was injected physiological saline2minutes before tracheal intubation, Group R0.5was injected0.5μg·kg-1remifentanil2minutes before trachea intubation and Group R1.0was injected1.0μg·kg-1remifentanil2minutes before tracheal intubation. Anesthesia induction: All patients were not given any premedicant. Evacuate the reservoir bag before anesthesia induction. Sevoflurane anesthetic vaporizer dial was set to8%, then begin to conduct anesthesia induction after60s. And deduct the face mask and direct the children to deeply breathe. Sevoflurane anesthetic vaporizer dial was decreased to3%-4%with oxygen(4L·min-1) after falling into sleep and assisted respiration was given when necessary.5mins after the induction, physiological saline was injected to Group S,0.5μg·kg-1remifentanil was injected to Group R0.5and1.0μg·kg-1remifentanil was injected to Group R1.0. After1minute tracheal intubation, mechanical ventilation was done. The concentration of sevoflurane was decreased to2%with oxygen(2L·min-1), tidal volume being (8～10)mL·kg-1, I/E (inspiratory/expiratory) being1:2,respiratory rate being16beat·min-1. Monitor and record the QTc, heart rate(HR) and mean arterial pressure(MAP) at different moments (before induction (T1), after induction1min(T2),3mins(T3),5mins(T4),1min after injection of remifentanil or physiological saline(T5), before intubation(T6) and1min after intubation (T7)) during sevoflurane induction.Results:changes of QTc:Compared with the basic value(T1), QTc of the three groups did not change obviously at induction1min, prolonged obviously at induction3mins(T3) and5mins(T4)(P<0.05). The differences of the three groups’QTc have not been statistically significant. After injection of physiological saline, the difference between T3-5in Group S have not been statistically significant. Compared with T3, T4the QTc in Group R0.5after injection of remifentanil0.5μg·kg-11min(T5) was shorter obviously (P<0.05), but longer than the basic value (P<0.05). Compared with T3, T4the QTc in Group R1.0after injection of remifentanil1.0μg·kg-1lmin(T5) was shorter obviously (P<0.01), but no difference with the basic value (P<0.05). Before intubation(T6), compared with respective the QTc in T5and T6have not been statistically significant. And the difference of the three groups were similar with T5. After intubation lmin(T7), QTc is longer than T3-T6in Group S (P<0.05). There was no difference between Group R0.5and R1.0, but shorter than Group S (P<0.01). Changes of MAP and HR:Those in T2-T4were lower than the basic value. There was not statistical significance inner or between the three groups. The value increased in three groups after intubation lmin(T7), compared with the basic, those in T5-T7were remarkably lower in Group R1.0and Group R0.5(P<0.05),innergroup, the MAP and HR kept stable.Conclusion:(1) The QTc were prolonged remarkably at induction3mins and5mins by inhaling high concentration sevoflurane, but no fatal arrhythmia happened;(2) The administration of remifentanil before intubation can supress the prolongation of QTc and the changes of MAP and HR effectively due to tracheal intubation during sevoflurane induction in children;(3) The effect of remifentanil1.0μg·kg-1is better than that of remifentanil0.5μg·kg-1on supressing QTc’s prolongation.