Cardiac and renal protective effects of dexmedetomidine in cardiac surgeries: A randomized controlled trial

Background: Cardiac and renal injuries are common insults after cardiac surgeries that contribute to perioperative morbidity and mortality. Dexmedetomidine has been shown to protect several organs against ischemia/reperfusion-(I/R) induced injury. We performed a randomized controlled trial to assess the effect of dexmedetomidine on cardiac and renal I/R injury in patients undergoing cardiac surgeries. Materials and Methods: Fifty patients scheduled for elective cardiac surgeries were randomized to dexmedetomidine group that received a continuous infusion of dexmedetomidine initiated 5 min before cardiopulmonary bypass (1 mu g/kg over 15 min, followed by 0.5 mu g/kg/h) until 6 h after surgery, whereas the control group received an equivalent volume of physiological saline. Primary outcome measures included myocardial-specific proteins (troponin-I, creatine kinase-MB), urinary-specific kidney proteins (N-acetyl-beta-D-glucosaminidase, alpha-1-microglobulin, glutathione transferase-pi, glutathione transferase alpha), serum proinflammatory cytokines (tumor necrosis factor alpha and interleukin-1 beta), norepinephrine, and cortisol levels. They were measured within 5 min of starting anesthesia (T-0), at the end of surgery (T-1), 12 h after surgery (T-2), 24 h after surgery (T-3), 36 h postoperatively (T-4), and 48 h postoperatively (T-5). Furthermore, creatinine clearance and serum cystatin C were measured before starting surgery as a baseline, and at days 1, 4, 7 after surgery. Results: Dexmedetomidine reduced cardiac and renal injury as evidenced by lower concentration of myocardial-specific proteins, kidney-specific urinary proteins, and pro-inflammatory cytokines. Moreover, it caused higher creatinine clearance and lower serum cystatin C. Conclusion: Dexmedetomidine provided cardiac and renal protection during cardiac surgery.