Dexamethasone treatment prior to reperfusion improves the survival of skin flaps subjected to secondary venous ischaemia

The potential use of the anti-inflammatory glucocorticoid, dexamethasone, to treat ischaemic skinflaps prior to reperfusion was investigated. Island flaps were raised in rats, subjected to arteriovenous ischaemia for 2 h, normal blood flow for 24 h, secondary venous ischaemia for 4 h and secondary reperfusion for 7 days. This sequence mimics the clinical sequence of free flap transfer followed by a subsequent venous thrombosis. Groups of 10 rats were administered with an intraperitoneal dose of either saline (controls) or dexamethasone (2.5 mg/kg) 30 min before the end of the venous ischaemia. Compared with viability of 70.0% in controls, dexamethasone treatment increased viability significantly to 92.0% (P<0.01). In skin flap tissue harvested at 24 h reperfusion, dexamethasone treatment resulted in significant attenuation of tissue water content, tissue myeloperoxidase activity and tissue hydroperoxide levels. Thus the protective effect of this agent may be explained by the combined reduction of oedema formation, neutrophil infiltration and free radical production, respectively. We conclude that a single systemic dose of dexamethasone prior to reperfusion may be beneficial in treating skin flaps that have undergone secondary venous ischaemia.