The second source of information regarding perfusion-oxygen needs for wound healing arises from indirect information . It is obvious that markedly increased blood flow and oxygen availability are required to heal a wound and control infection.(19) Perfusion and oxygen requirements are minimal for noncritical tissues that do not have wounds or infections because they are in a steady-state, resting status. An example of this would be the feet of the patient with advanced peripheral artery disease. If a relatively minor wound occurs in one foot, healing may not occur, and a lower limb amputation becomes necessary. In contrast, in the opposite limb that does not have a wound, but perfusion is equally poor, the foot is not immediately at risk for an amputation.