Agreement between ICU clinicians and electrophysiology cardiologists on the decision to initiate a QTc-interval prolonging medication in critically ill patients with potential risk factors for torsade de pointes: a comparative, case-based evaluation

Study objectives: To measure concordance between different intensive care unit (ICU) clinicians and a consensus group of electrophysiology (EP) cardiologists for use of a common rate-corrected QT interval (QTc)-prolonging medication in cases containing different potential risk factor(s) for torsade de pointes (TdP).

Design: Prospective case-based evaluation.

Setting: Academic medical center with 320 beds.

Subjects: Medical house staff (MDs) and ICU nurses (RNs) from one center and select critical care pharmacists (PHs).

Intervention: Completion of a survey containing 10 hypothetical ICU cases in which patients had agitated delirium for which a psychiatrist recommended intravenous haloperidol 5 mg every 6 hours. Each case contained different potential risk factor(s) for TdP in specific combinations. A group of five EP cardiologists agreed that haloperidol use was safe in five cases and not safe in five cases.

Measurements and main results: For each case, participants were asked to document whether they would administer haloperidol, to provide a rationale for their decision, and to state their level of confidence in that decision. Most clinicians (92 of 115 [80%]) invited to participate completed the cases. Among the five cases where EP cardiologists agreed that haloperidol was not safe, 29% of respondents felt that haloperidol was safe. Conversely, in the five cases where EP cardiologists felt haloperidol was safe, 21% of respondents believed that it was not safe. Overall respondent-EP cardiologist agreement for haloperidol use across the 10 cases was moderate (κ = 0.51). MDs and PHs were in agreement with the EP cardiologists more than RNs (p=0.03). Interprofessional variability existed for the TdP risk factors each best identified. Clinician confidence correlated with EP cardiologist concordance for MDs (p=0.002) and PHs (p=0.0002), but not for RNs (p=0.69).

Conclusion: When evaluating use of a QTc interval-prolonging medication, ICU clinicians often fail to identify the TdP risk factors that EP cardiologists feel should prevent its use. Clinician-EP cardiologist concordance varies by the specific risk factor(s) for TdP and the ICU professional conducting the assessment.