Effect of remifentanil on mean arterial pressure, heart rate and QTc interval during tracheal intubation of general anesthesia patients

Objective To evaluate the effect of remifentanil on mean arterial pressure (MAP), heart rate (HR) and QTc interval during tracheal intubation of general anesthesia patients. Methods Seventy-five ASA Ⅰ -Ⅱ grade patients were selected and allocated to receive either saline (group C), remifentanil 0.50 μg/kg (group R1) or remifentanil 0.75 μg/kg(group R2) by random digits table with 25 cases in each, they were administrated as a bolus intravenous, followed by a continuous infusion at 0.10 μg/ (kg·min), 1 min before laryngoscopy. All patients received fentanyl 3 μg/kg,propofol 1.0 - 1.5 mg/kg and vecuronium 0.1 mg/kg. The ECG.MAP and HR were recorded prior to induction of anesthesia (T0), 2 min following the start of drug intravenous of fentanyl and propofol with vecuronium (T1), 1 min following remifentanil or saline (T2), before laryngoscopy(T3), 30 s (T4), 2 min (T5) and 4 min (T6) after intubation. Results The QTc interval was significantly prolonged immediately following intubation in group C and group R1, but it remained stable in group R2, compared with the QTc interval just before laryngoscopy. In group R2, QTc interval was significantly shorter at T4-T6 compared to group C(P＜ 0.05 or ＜ 0.01). QTc interval significantly increased from baseline at T4 in group R1 and T4-T6 in group C (P＜ 0.05 or ＜ 0.01). The number of patients with QTc interval ＞ 440 ms were significantly greater immediately following tracheal intubation in group C than that in group R2 [44% (11/25) vs. 12% (3/25)] (P ＜ 0.05). Conclusions QTc interval increases following tracheal intubation during induction of anesthesia using fentanyl and propofol. Intravenous of remifentanil attenuates the QTc interval prolongation associated with tracheal intubation. In addition, remifentanil decreases the hemodynamic responses to tracheal intubation. Key words: Catheterization, peripheral;  Remifentanil;  QTc interval;  Hemodynamic processes