Effects of conventional vs high-dose rocuronium on the QTc interval during anesthesia induction and intubation in patients undergoing coronary artery surgery: a randomized,double-blind,parallel trial

Myocardial ischemia, as well as the induction agents used in anesthesia, may causecorrected QT interval (QTc) prolongation. The objective of this randomized,double-blind trial was to determine the effects of high- vsconventional-dose bolus rocuronium on QTc duration and the incidence of dysrhythmiasfollowing anesthesia induction and intubation. Fifty patients about to undergocoronary artery surgery were randomly allocated to receive conventional-dose (0.6mg/kg, group C, n=25) or high-dose (1.2 mg/kg, group H, n=25) rocuronium afterinduction with etomidate and fentanyl. QTc, heart rate, and mean arterial pressurewere recorded before induction (T0), after induction (T1), after rocuronium (justbefore laryngoscopy; T2), 2 min after intubation (T3), and 5 min after intubation(T4). The occurrence of dysrhythmias was recorded. In both groups, QTc wassignificantly longer at T3 than at baseline [475 vs 429 ms in groupC (P=0.001), and 459 vs 434 ms in group H (P=0.005)]. The incidenceof dysrhythmias in group C (28%) and in group H (24%) was similar. The QTc afterhigh-dose rocuronium was not significantly longer than after conventional-doserocuronium in patients about to undergo coronary artery surgery who were induced withetomidate and fentanyl. In both groups, compared with baseline, QTc was mostprolonged at 2 min after intubation, suggesting that QTc prolongation may be due tothe nociceptive stimulus of intubation.