The dynamic properties of tissue oxygen in healing flaps.

Oxygen delivery to random pattern and musculocutaneous flaps was investigated in a canine model. Oxygen tension was measured in the proximal and distal portions of each flap and in adjacent normal skin by means of a recently developed technique. The effect of delay techniques on tissue oxygen tension was also examined with modifications of the same flap model. All measurements were made over a range of inspired oxygen concentrations (21% to 100%) both before operation and at intervals up to 15 days after operation. Tissue oxygen tensions were significantly higher in the musculocutaneous flaps than in random pattern flaps up to 6 days after operation. They were higher in the proximal portions than in the distal portions in each flap type. This difference was greater in the random pattern flap. Delay techniques prevented the early dramatic decrease in postoperative oxygen tension seen in random pattern flaps. Differences in the pattern of oxygen delivery to random pattern and musculocutaneous flaps may in part explain the greater reliability of musculocutaneous flaps when transposed in the presence of infection.