Simultaneous Measurement of Tissue pCh and Perfusion During Muscular Contraction of the Latissitnus Dorsi

The latissiimis dorsi muscle (LDM) receives its primary blood supply from a single nutrient artery located at its proximal insertion and it has not previously been established whether this effects the regional perfusion and nutrition of the muscle, A microelectrode technique was used to measure local oxygenation and permsion simultaneously at multiple sites in the rabbit LDM at rest, during and after repeated muscular contraction induced by electrical stimulation with a fatigue-testing protocol. In the resting state there were no significant differences in perfusion or oxygenation in different regions of the LDM. However, the proximal perfusion was greater than distal perrusion during muscular contraction (increase from baseline 173 ± 9% and 137 ± 5%) and during the first 20 minutes of recovery. Tissue oxygenation was maintained at constant levels in the proximal region throughout contraction and recovery whereas there was a significant decrease in distal p02 of 10.2 ± S.SmmHg during contraction and of 5.4 ± 4,2mmHg during the first 20 minutes of recovery. The evidence suggests that distal areas of the LDM cannot maintain sufficient perfusion during contraction to prevent a fall in tissue p02-This has important implications on the clinical applications of the LDM as a pedicled muscle flap for cardiac assistance.