Protective effect of dexmedetomidine on Tourniquet induced lung injury in patients undergoing total knee arthroplasty: A randomized trial

To investigate whether dexmedetomidine (Dex) can reduce the severity of tourniquet-induced lung injury. 36 patients undergoing total knee arthroplasty with a tourniquet were randomly assigned to the control (ischemia/reperfusion [I/R]) group and Dex group. Patients in the Dex group received a loading dose of Dex (0.8 μg/kg over 10 min intravenously) followed by continuous infusion of Dex (0.5 μg/kg/h intravenously) until the end of the surgery. The I/R group received an equal amount of 0.9% saline instead of Dex. The serum concentrations of tumor necrosis factor-α (TNF-α), Clara cell protein (CC-16), soluble receptor for advanced glycation end products (sRAGE), and brain-derived neurotrophic factor (BDNF) were measured and arterial blood gas analysis was performed before anesthesia and 30 min, 6 h, and 24 h after tourniquet release. In the I/R group, compared with baseline, the TNF-α, CC-16, and sRAGE concentrations were higher ( p < 0.05) and the BDNF concentration was lower ( p < 0.05) at most time points. In the Dex group, the TNF-α, CC-16, and sRAGE concentrations were lower than those in the I/R group ( p < 0.05), whereas the concentration of BDNF was higher ( p < 0.05). In the arterial blood gas analysis, the Dex group showed a significantly higher partial pressure of oxygen and arterial/alveolar oxygen tension ratio ( p < 0.05) and a significantly lower alveolar/arterial oxygen tension difference than the I/R group ( p < 0.05). Dex administration partly inhibits the release of proinflammatory cytokines, affording protection against tourniquet-induced lung injury.