A randomized control trial comparing prophylactic dexmedetomidine versus clonidine on rates and duration of delirium in older adult patients undergoing coronary artery bypass grafting

Study objective: Postoperative delirium occurs in 20-50% of elderly patients undergoing cardiac surgery and increases morbidity and mortality. We investigated whether prophylactic dexmedetomidine could reduce delirium incidence in elderly patients after coronary artery bypass grafting (CABG), compared with clonidine.

Design: Prospective observational trial.

Setting: Academic university hospital.

Participants: Patients (60-70 years old) who underwent CABG and received either dexmedetomidine or clonidine infusion postoperatively.

Interventions: Patients were randomly allocated to dexmedetomidine or clonidine groups. In the dexmedetomidine group, patients received an initial infusion of 0.7-1.2 μg/kg/h; sedation and analgesia were evaluated after 45-60 min. If the Richmond assessment sedation score (RASS) increased from +1 to +4, the infusion rate was increased by 0.1-0.2 μg/kg/h every 30 min, up to 1-1.4 μg/kg body-weight/h. Dexmedetomidine infusion was not discontinued pre-extubation; thereafter, infusion was reduced by 0.1 μg/kg/h until 0.2 μg/kg/h. The maximum infusion duration was 72 h. In the clonidine group, patients received an initial infusion of 0.5 μg/kg, followed by 1-2 μg/kg/h, if the RASS changed from +1 to +4. This was continued throughout mechanical ventilation.

Measurements: Patients were followed up to 5 days post-surgery. Delirium incidence, extubation time, lengths of intensive care unit (ICU) and hospital stay, need for inotropic support or vasopressors, mean arterial blood pressure and heart rate, hospital mortality rate, total postoperative morphine dose, number of patients receiving haloperidol, and adverse events were recorded.

Main results: Two-hundred-and-eighty-six patients (dexmedetomidine, 144; clonidine, 142) were studied. Dexmedetomidine was associated with lower risk and duration of delirium, shorter mechanical ventilation duration and ICU stay, lower mortality rate, and lower morphine consumption than the clonidine group. Dexmedetomidine significantly decreased heart rates after ICU admission.

Conclusions: Postoperative infusion of dexmedetomidine provides a feasible option for postoperative control of delirium after CABG in adult patients.