(1467) Risk Factors for Bradycardia in Patients on Dexmedetomidine: A Retrospective Study

Introduction: Dexmedetomidine is a medication commonly used for sedation in critically ill patients due to its sedative and analgesic properties without significant respiratory depression. Previous studies suggest that dexmedetomidine may reduce the incidence of delirium and shorten the duration of mechanical ventilation. However, dexmedetomidine is also associated with bradycardia, and the risk factors for this adverse effect are not well understood. This retrospective study aims to elucidate the risk factors contributing to bradycardia in patients administered dexmedetomidine.

Methods: The study was conducted in a large university healthcare system, including adults aged 18 and older who were admitted to ICUs in four hospitals between 2014 and 2022. Bradycardia was defined as a heart rate of less than 60 beats per minute within 24 hours of starting dexmedetomidine. Demographics and comorbidities were compared between those who developed bradycardia and those who did not. Outcomes of inpatient mortality and length of stay were also compared. Bonferroni correction was used for multiple comparisons, with a p-value of 0.003 considered significant.

Results: 15,331 patients, divided into those who developed bradycardia (N=3,475) and those who did not (N=11,856). The bradycardia group was older (mean age: 61.6 vs. 60.2 years, p< 0.001) and had a lower incidence of myocardial infarction (17.0% vs. 21.3%, p< 0.001) and congestive heart failure (46.2% vs. 49.9%, p< 0.001), but higher incidences of cerebrovascular disease (32.7% vs. 27.9%, p< 0.001), liver disease (24.0% vs. 19.0%, p< 0.001), hypertension (8.1% vs. 6.0%, p< 0.001), and cancer (14.8% vs. 12.2%, p< 0.001). The length of stay was longer for the bradycardia group (mean: 22.1 vs. 19.4 days, p< 0.001), and they had a higher mortality rate (16.9% vs. 10.8%, p< 0.001).

Conclusions: The study identified several significant risk factors for bradycardia in treated with dexmedetomidine, including older age and higher incidence of several comorbidities. Patients who had bradycardia also had higher mortality and longer hospital length of stay. Further investigation is needed to identify other risk factors and develop scoring systems that can identify patients at highest risk for bradycardic response to dexmedetomidine.