Effects of dexmedetomidine on inflammatory mediators after tourniquet-induced ischemia-reperfusion injury: a...

Tourniquet use during total knee arthroplasty (TKA) produces ischemia-reperfusion injury (IRI), with systemic release of inflammatory cytokines and reactive oxygen species upon tourniquet release. We conducted a randomized, placebo-controlled, double-blind trial to examine whether dexmedetomidine (DEX) as an adjunct during general anesthesia in patients undergoing unilateral TKA could attenuate the rise in inflammatory cytokines and oxidative stress.

Sixty-eight patients were randomized to either the control or DEX group. DEX was administered at a loading dose of 0.5 μg/kg, followed by an infusion of 0.4 μg/kg/h. We measured serum levels of malondialdehyde (biomarker of oxidative stress) and proinflammatory cytokines (interleukin-6 [IL-6] and tumour necrosis factor-α [TNF-α]) preinduction (baseline), 60 and 90 min post-tourniquet release. We also assessed hemodynamics, intraoperative remifentanil consumption, and postoperative pain scores and analgesic consumption.

Malondialdehyde was higher than baseline after tourniquet release in both groups (P≤0.001), but the levels were similar between groups at all times. TNF-α was significantly higher than baseline at 60 min post-tourniquet release only in the control group (P=0.009). Serum IL-6 increased significantly above baseline at 60 and 90 min post-tourniquet release in both groups (P<0.001). At 90 min, IL-6 was significantly lower in the dexmedetomidine group than in the control group (P=0.049). Remifentanil consumption, heart rate, and pain scores were significantly lower in the dexmedetomidine group.

Our results suggest that dexmedetomidine as an adjunct to general anesthesia attenuated the rise in proinflammatory cytokines, providing protective effects in tourniquet-induced IRI.