Effect of Low-Dose Dexmedetomidine as an Anesthetic Adjuvant on Intraoperative Hemodynamics and Prognosis in Patients...

Dexmedetomidine, as an anesthetic adjuvant, has a guideline-recommended dose of 0.2-0.7 µg/kg/h. We sought to compare the intraoperative hemodynamic and prognostic performance of cardiac surgical patients receiving the guideline-recommended dose of dexmedetomidine to those receiving a dose lower than the guideline.

A retrospective cohort study was conducted on 871 patients who were maintained under anesthesia with dexmedetomidine during cardiac surgery, of whom 414 patients received the guideline-recommended dose as a control group and 457 below the guideline-recommended dose as a low-dose group. A cohort of patients in the low-dose and control group (155 vs 155) was created by propensity score matching. The primary outcome was a composite of adverse outcomes, including bradycardia, atrial fibrillation, and hypotension. Secondary outcomes assessed included delirium, analgesic medication use, cardiac intensive care unit (CICU) length of stay, and duration of mechanical ventilation.

After propensity matching, the maximum heart rate difference, maximum systolic blood pressure difference, maximum diastolic blood pressure value, and maximum mean arterial pressure difference before and after cardiopulmonary bypass and after cessation of pumping were significantly different in the low-dose group compared with the control group (P < 0.01). Compared with the control group, the low-dose group had a higher incidence of postoperative atrial fibrillation (34.8% vs. 23.9%, P = 0.034), and the length of stay in the cardiac intensive care unit (median 4 days, quartiles 3-5 days vs. median 3 days, quartiles 3-4 days, P < 0.001) was significantly longer.

Compared with lower dose, receiving dexmedetomidine pumped at the guideline-recommended dose in anesthetic assistance for cardiac surgery resulted in smoother intraoperative hemodynamic performance and an improvement in the incidence of postoperative atrial fibrillation, shorter stay in the cardiac intensive care unit, and better prognostic performance.