Dexmedetomidine Pretreatment Confers Myocardial Protection and Reduces Mechanical Ventilation Duration for Patients Undergoing Cardiac Valve Replacement under Cardiopulmonary Bypass

Purpose: The study aims to assess the effects of dexmedetomidine (Dex) pretreatment on patients during cardiac valve replacement under cardiopulmonary bypass. Methods: For patients in the Dex group (n = 52), 0.5 mu g/kg Dex was given before anesthesia induction, followed by 0.5 mu g/kg/h pumping injection before aortic occlusion. For patients in the control group (n = 52), 0.125 ml/kg normal saline was given instead of Dex. The patients in the Dex group had longer time to first dose of rescue propofol than the control group ( P = 0.003). The Dex group required less total dosage of propofol than the control group ( P = 0.0001). Results: The levels of cardiac troponin I (cTnI), creatine kinase isoenzyme MB (CK-MB), malondialdehyde (MDA), and tumor necrosis factor- alpha (TNF- alpha ) were lower in the Dex group than the control group at T4, 8 h after the operation (T5), and 24 h after the operation (T6) ( P <0.01). The Dex group required less time for mechanical ventilation than the control group ( P = 0.003). Conclusion: The study suggests that 0.50 mu g/kg Dex pretreatment could reduce propofol use and the duration of mechanical ventilation, and confer myocardial protection without increased adverse events during cardiac valve replacement.