Association Between Dexmedetomidine Use and Duration of Invasive Mechanical Ventilation After Cardiac Surgery: A Hospital Registry Study

BACKGROUND: Dexmedetomidine is commonly used for sedation after cardiac surgery, but its role in facilitating weaning from mechanical ventilation remains unclear, with the existing evidence yielding inconsistent findings. In this study, we hypothesized that dexmedetomidine administration is associated with a prolonged duration of mechanical ventilation after cardiac surgery. METHODS: We conducted a retrospective cohort study of adult patients who underwent nonemergent cardiac surgery under cardiopulmonary bypass at Montefiore Medical Center, Bronx, New York, between May 2016 and June 2021. The primary exposure was the use of dexmedetomidine infusion compared to no dexmedetomidine infusion. The secondary exposure was the average, total sedative dose patients received during mechanical ventilation. The sedative dose was categorized into low and high exposure groups for analysis. Adjusted differences between groups were calculated using geometric means to enhance the interpretability of the findings. RESULTS: Data from 2191 cases were analyzed, including 1455 (66.4%) patients who underwent coronary artery bypass graft surgeries (CABG), 521 (23.8%) valve surgeries, and 215 (9.8%) combined CABG and valve surgeries. The median (interquartile range) duration of mechanical ventilation was 406 (297–837) minutes. Dexmedetomidine infusion was associated with a longer duration of mechanical ventilation (adjusted absolute difference [ADadj] 42 minutes; 95% confidence interval [CI], 11–75; adjusted model estimates [MEadj] 1.1; 95% CI, 1.0–1.2; P = .007) compared with no dexmedetomidine administration. High sedative dose, compared to low sedative dose, was independently associated with prolonged mechanical ventilation (ADadj 71 minutes; 95% CI, 42–101; MEadj 1.2; 95% CI, 1.1–1.2; P < .001). Furthermore, the sedative dose significantly modified the association between dexmedetomidine use and ventilation duration (P for interaction <.001). Among patients with a high sedative dose, dexmedetomidine was associated with shorter mechanical ventilation (ADadj −233 minutes; 95% CI, −324 to −125; MEadj 0.7; 95% CI, 0.6–0.8; P < .001). CONCLUSIONS: Dexmedetomidine use, and a high sedative dose during mechanical ventilation were independently associated with prolonged mechanical ventilation after cardiac surgery. Among patients with a high sedative dose, dexmedetomidine was associated with shorter mechanical ventilation duration.