Does dexmedetomidine have a cardiac protective effect during non-cardiac surgery? A randomised controlled trial.

This study was designed to determine the effects of dexmedetomidine on perioperative myocardial injury by observing peripheral circulatory changes in response to tracheal intubation and extubation, myocardial enzyme levels, myocardial ischaemia improvements, cardiovascular adverse events and cytokines in patients with coronary heart disease (CHD) undergoing non-cardiac surgery. This study was a prospective, randomized, double-blind trial. Eighty patients having CHD were scheduled for elective hip-replacement surgery and randomly allocated to receive a loading dose of 1 μg/kg dexmedetomidine followed by a 0.2 μg/kg per h infusion (Dex group; n = 40) or normal saline (control group; n = 40). Systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, rate-pressure product and changes in ST-T segment on the electrocardiogram were recorded every 5 min during surgery. Serum creatine kinase-MB (CK-MB), cardiac troponin I (cTnI), glycogen phosphorylase BB (GP-BB), interleukin (IL)-6 and tumour necrosis factor (TNF)-α protein levels were determined preoperatively, at the end of surgery and 12 and 24 h after surgery. The improvement rate of myocardial ischaemia was higher in the Dex than control group (87.5% vs 32.5%, respectively; P < 0.05). In addition, the Dex group had lower serum CK-MB, IL-6, cTnI and GP-BB concentrations than the control group (P < 0.05). There was no significance difference in TNF-α between the two groups (P > 0.05). Dexmedetomidine can reduce myocardial injury and cytokine levels in patients with CHD undergoing non-cardiac surgery.