Muscle blood flow following thermal injury

Peripheral circulation is markedly increased during the hyperdynamic-hypermetabolic phase of thermal injury and appears to be directed primarily to the burn wound. To determine whether any portion of this extra blood flow reaches another major peripheral vascular bed, blood flow in the tibialis anterior muscle of the lower leg was measured by 133Xe clearance in ten hemodynamically stable, nonseptic burn patients (mean burn size = 42.5% total body surface) and five control subjects. Muscle blood flow was 3.52 +/- 0.26 ml/100 g.min (mean +/- S.E.M.) in these patients and 3.29 +/- 0.24 in controls, indicating that resting muscle perfusion was unaffected by the extent of total body surface injury, size of leg burn, or elevated rectal temperature (38.2 +/- 0.2 degrees C) of the patients. These results confirm the interpretations of previous studies suggesting that most of the increased peripheral blood flow following thermal injury is directed to the surface wound. Local and systemic factors responsible for the maintenance of muscle perfusion in the face of alterations in muscle metabolism following thermal injury are discussed.