This suggests that HBO is affecting a systemic circulating element(i.e. the neutrophil) rather than acting on the ischemic endothelium. A trend toward improvement has also been noted in several HBO groups treated during reperfusion, but numbers are too small at this point to permit statistical comparison to controls. The completion of this study will be important in determining if the beneficial microcirculatory effects of HBO translate into improved function in skeletal muscle subjected to I-R injury, in addition to determining the optimal reperfusion treatment protocol