Effects of dexmedetomidine on the function of distal organs and oxidative stress after lower limb ischaemia–reperfusion in elderly patients undergoing unilateral knee arthroplasty

AIMS This study aims to evaluate the effects of dexmedetomidine on organ function, inflammation response, and oxidative stress in elderly patients following iatrogenic lower limb ischaemia-reperfusion (IR) during unilateral total knee arthroplasty. METHODS Following unilateral total knee arthroplasty, 54 elderly patients were randomized to receive either intraoperative intravenous injection of dexmedetomidine (n = 27) or equivalent volume of 0.9% saline (n = 27). Blood samples were harvested at 5 minutes before lower limb tourniquet release (baseline); and 1, 6 and 24 hours after tourniquet release. Surrogate markers of cardiac, pulmonary, hepatic and renal function, oxidative stress, inflammatory response, along with parasympathetic and sympathetic activity were recorded and analysed. RESULTS The levels of blood xanthine oxidase, creatine kinase, lactic acid and respiratory index increased in patients following tourniquet-induced lower limb IR injury. Dexmedetomidine administration decreased the respiratory index (P = .014, P = .01, and P = .043) and the norepinephrine level (P