J. Zakko1, A. Francis2, C. V. Murphy2, D. A. Eiferman1 1Ohio State University Wexner Medical Center,Department Of Surgery,Columbus, OH, USA 2Ohio State University Wexner Medical Center,Department Of Pharmacy,Columbus, OH, USA
Introduction: ICU delirium is common in the SICU population and many patients are treated with medications that can cause QTc prolongation, which is a risk factor for the development of Torsades de Pointes (TdP). Serial ECGs are often ordered in this population to assess for QTc prolongation, and effective medications are routinely discontinued due to an increase in QTc for fear of progression to TdP. There is limited data available to determine the risk of TdP in the surgical intensive care unit (SICU) patient population as well as any morbidity from QTc prolongation. This study aims to determine if QTc prolongation is associated with development of TdP.
Methods: A single-center retrospective cohort study was conducted to evaluate QTc prolongation and development of TdP amongst non-cardiac SICU patients being treated for ICU delirium at a large academic medical center. Delirium treatment included at least one of the following medications: haloperidol, risperidone, quetiapine, or olanzapine. QTc prolongation was defined as QTc > 500 milliseconds or >20% increase from baseline. Exclusion criteria included ventricular pacing, bundle branch blocks, incarceration, pregnancy, patients on select antipsychotics prior to admission, and congenital long QT syndrome. The primary outcome was to determine prevalence of QTc prolongation and TdP. Secondary outcomes included SICU mortality and risk factors for QTc prolongation. Univariate and multivariate logistic regression models were constructed for assessment of the outcomes.
Results: Eighty patients were eligible for evaluation. Eight (10%) patients had QTc prolongation. There were no cases of TdP. Assessing patient demographics, concomitant antiarrhythmic and antidepressant use, history of heart disease, diuretic use, hepatic dysfunction, SICU length of stay, length of delirium treatment, and SICU mortality in univariate and multivariate analysis yielded no statistically significant association with development of QTc prolongation, morbidity, or mortality.
Conclusion: Among SICU patients receiving treatment for ICU delirium, the frequency of QTc prolongation was only 10% in our cohort with no cases of TdP. Furthermore, univariate and multivariate analysis did not demonstrate a significant correlation between QTc prolongation and morbidity or mortality. These results suggest that QTc prolongation due to medications used to treat delirium does not lead to the development of cardiac arrhythmias. Furthermore, we propose that serial ECG monitoring may be overused and the subsequent discontinuation of delirium-treating medications may not be necessary in this patient population.