Dexmedetomidine for heart rate control and renal protectionin patients undergoing mitral valve replacement for tightmitral stenosis

Background Dexmedetomidine (DXM) is an α2 adrenoceptor agonist that reduces the sympathetic outflow from the central nervous system resulting in bradycardia and hypotension.We used this drug in this randomized controlled double-blind study to test its efficacy in controlling the heart rate and its safety regarding renal function in patients undergoing mitral valve replacement surgery.Patients and methodsA total of 70 patients scheduled for mitral valve replacement were randomly allocated into two groups: in group D, 35 patients received DXM 1 ❍g/kg bolus dose over 10 min followed by an infusion of 0.5 ❍g/kg/h. In group C, 35 patients received saline bolus and infusion by the same method instead of DXM. The heart rate was measured at induction of anesthesia, after the end of bolus infusion, at skin incision, and every 10 min till the start of the cardiopulmonary bypass. We also measured the urine interleukin-18 level during the first 12 h of surgery and serum creatinine and blood urea for 3 days postoperatively.ResultsThe mean heart rate was significantly lower after bolus infusion, at skin incision, at 10 and 30 min, and just before bypass in the DXM group. Also, the urine output was higher in the DXM group during surgery and on the first postoperative day of surgery. No significant difference was found regarding other parameters of renal functions.ConclusionDXM can be used effectively in reducing the heart rate in patients undergoing mitral valve replacement surgery and was associated with an increase in the urinary output, and it did notalter the renal function in this cohort of patients.