Changes in QTc associated with a rapid bolus dose of dexmedetomidine in patients receiving TIVA: a retrospective study.
BACKGROUND
Clinical indications for the perioperative use of dexmedetomidine in pediatric anesthesia are accumulating. However, in 2013, dexmedetomidine was added to the list of medications with possible risk of prolonging the QT interval and/or inducing Torsades de Pointes. Unfortunately, current evidence for dexmedetomidine-induced QT prolongation is sparse and somewhat contradictory.


OBJECTIVE
The purpose of this study was to evaluate temporal changes in corrected QT interval (QTc) after a rapid bolus administration of dexmedetomidine under total intravenous anesthesia (TIVA) with a standardized propofol and remifentanil administration.


METHODS
Electrocardiography (ECG) and corresponding trend data were extracted from automated electronic data capture of physiological monitoring. Ten-second epochs of ECG data were extracted in 1-min intervals for 12 min, starting 1 min before dexmedetomidine bolus administration, and ending 10 min after. QT intervals were extracted using an automated routine in MATLAB, and corrected for heart rate (HR) using Bazett's (QTcB) and Fridericia's formulas (QTcF). QTcB and QTcF were compared using Wilcoxon signed-rank test between baseline measurements and the subsequent four interval values.


RESULTS
Data from 21 subjects (17 male) with median (range) age 7.1 (5.4-9.5) yr, weight 23.6 (16.2-36.7) kg, and height 121 (103-140) cm were analyzed. Bolus administration of dexmedetomidine reduced HR in all subjects (median 22%), and caused transient reduction of QT interval, with its peak at 1-min postbolus administration: QTcB (median reduction 30.7 ms, P < 0.001) or QTcF (median reduction 15.4 ms, P = 0.001); QT shortening became statistically insignificant 4 min following dexmedetomidine bolus administration for QTcB and 2 min for QTcF.


CONCLUSIONS
In this study, a rapid bolus of dexmedetomidine transiently shortened corrected QT intervals. However, these effects are confounded by dexmedetomidine-induced bradycardia. These findings should be confirmed in pediatric studies without concomitant TIVA administration and with optimized correction of baseline HR.
Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, BC, Canada.
Matthias
http://orcid.org/0000-0003-2193-178X
M
Görges
Department of Anesthesiology, Pharmacology, and Therapeutics, The University of British Columbia, Vancouver, BC, Canada.
Simon D
SD
Whyte
Division of Cardiology, Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada.
Shubhayan
S
Sanatani
Department of Anaesthesia, Great Ormond Street Hospital, London, UK.
Joy
J
Dawes
Department of Anesthesiology, Pharmacology, and Therapeutics, The University of British Columbia, Vancouver, BC, Canada.
Carolyne J
CJ
Montgomery
Department of Anesthesiology, Pharmacology, and Therapeutics, The University of British Columbia, Vancouver, BC, Canada.
J Mark
JM
Ansermino
D061605:Administration, Intravenous; D000771:Anesthesia, Intravenous; D018686:Anesthetics, Intravenous; D002648:Child; D002675:Child, Preschool; D020927:Dexmedetomidine / Q000008:administration & dosage* / Q000009:adverse effects*; D004562:Electrocardiography / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008133:Long QT Syndrome / Q000139:chemically induced* / Q000453:epidemiology*; D008297:Male; D016343:Monitoring, Intraoperative; D010880:Piperidines; D015742:Propofol; D000077208:Remifentanil; D012189:Retrospective Studies
D018686:Anesthetics, Intravenous; D010880:Piperidines; D020927:Dexmedetomidine; D000077208:Remifentanil; D015742:Propofol
anesthesia; children; dexmedetomidine; electrocardiography/methods; heart conduction system/drug effects