QT PROLONGATION AND CARDIAC ARRHYTHMIAS ASSOCIATED WITH DROPERIDOL USE IN CRITICAL EMERGENCY DEPARTMENT PATIENTS (ABSTRACT).

Martel M, et al. Acad Emerg Med 2003 10: 510-b-511-b.

BACKGROUND: QT prolongation and torsade de pointes (TdP) have been reported as a complication of droperidol (Drop).

OBJECTIVES: To determine the change in the corrected QT interval (QTc) and the incidence of cardiac arrhythmias in critically ill patients who received Drop.

METHODS: The medical records of all critical care ED patients from 1/1/1997 to 12/31/2001 were hand searched for those who received Drop and an ECG in the ED. Drop dose, ECG time, QTc intervals, and cardiac rhythm were reviewed. ECGs with atrial fib/flutter, right or left bundle branch block, or paced rhythms were excluded. Data was analyzed in 3 groups, patients with an ECG only before Drop, only after Drop, and those with ECGs both before and after Drop. Data was analyzed using descriptive statistics and chi-squared.

RESULTS: 11,583 charts were reviewed, 1172 patients received Drop, and 396 had both an ECG and Drop in the ED. 44 patients were excluded due to abnormal rhythm, bundle branch block, or paced rhythm. 96 patients had an ECG only before Drop (mean 33.3min prior), average dose of 2.75mg, and mean QTc of 435.0ms (95% CI 428.1–441.9ms). 186 patients had an ECG only after Drop (mean 25.9min after), average dose of 3.68mg, and mean QTc of 433.3ms (95% CI 427.8 to 438.8ms). 114 patients had ECGs before and after Drop (mean time 28.2min before, 108.8min after), average dose of 2.21mg, and mean QTc of 435.7ms (95% CI 426.7–444.7ms) and 435.8ms (95% CI 427.5–444.1ms) before and after Drop, respectively. The mean ratio of the QTc before and after Drop is 1.005 (95% CI 0.985–1.025). 2 patients had ventricular arrhythmias in the before Drop group, 3 in the after Drop group, and 4 in the before and after Drop group (p = 0.5). 1 patient had an unrecorded event of TdP with a QTc of 466ms after conversion.

CONCLUSIONS: We detected no statistical difference in the change of the QTc interval or occurrence of ventricular arrhythmias in critically ill patients who received Drop.

COMMENT: For further comments on the black box warning of droperidol, I recommend reading the article by Horowitz, et al in Acad Emerg Med, 2002 9:615-618.