Journal: Anaesthesia 63(10):1056-1060, 2008.
Reprint: Department of Anaesthesiology and Pain Medicine and Anaesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea (DW Han, MD)
Faculty Disclosure: Abstracted by J. Joyce, who has nothing to disclose.
Prolongation of the corrected QT (QTc) interval can be inherited or acquired. The acquired form is associated with anesthetic drugs, cardiac, neurological, and electrolyte disturbances. A prolonged QTc interval can degenerate into potentially life-threatening complications. Evidence regarding the effects of propofol on the QTc interval is still conflicting, while thiopental and most volatile anesthetics are known to prolong the QTc interval. During laryngoscopy and intubation, QTc prolongation may be exacerbated, which is thought to be caused by sympathetic stimulation. The administration of potent opioid or β-adrenergic blockade is generally recommended to attenuate sympathoadrenal responses to laryngoscopy and intubation.
The aim of this study was to investigate the effect of fentanyl on the changes in the QTc interval during propofol induction in healthy patients in a placebo-controlled, randomized, double-blind study. The results presented show that the QTc interval was significantly prolonged after tracheal intubation during the administration of propofol in healthy patients. The authors also discovered that the administration of fentanyl 2 mcg/kg before induction attenuates the QTc interval prolongation associated with laryngoscopy and intubation.
The effect of opioids on the prolongation of the QTc interval during induction is unclear. It is possible that the cause of QTc interval prolongation associated with intubation is not entirely attributable to sympathoadrenal stimulation since multiple anesthetic drugs are usually being administered during induction. Fentanyl may have a direct effect on the QTc, although evidence is not clear cut. Recently, it has been reported in another study using human cardiac myocytes that opioid agonists can block cardiac potassium currents, which suggests that fentanyl may prolong action potential duration related to QT interval prolongation.
Propofol is recommended as a safe drug for patients with QTc prolongation, but its effect on the QTc interval remains controversial. |
