OBJECTIVE The aim of this study was to investigate the skeletal muscle tissue oxygen pressure (PtO2) distributions during early reperfusion (10-45 min) after prolonged ischaemia in a rat animal model. METHODS Skeletal muscle ischaemia was induced in anaesthetised rats by applying a tourniquet on the left thigh for 3 h (group I) or 4 h (group II), and tissue oxygen pressure measurements were made after 10-45 min of reperfusion. Assessment of PtO2 was made by a multiwire Clark-type oxygen microelectrode, placed on the surface of the left tibialis anterior muscle. RESULTS During reperfusion a similar PtO2 pattern was evaluated after both 3 and 4 h of total ischaemia, where the sum PtO2 distributions were shifted to the left associated with low tissue oxygen pressure values. After 10 min of reperfusion the median PtO2 was 0.28 kPa and 0.18 kPa, in groups I and II, respectively; after 45 min of reperfusion 0.61 kPa and 0.60 kPa, respectively. The median PtO2 in the non-ischaemic muscle in groups I and II were 2.19 and 2.17 Pa. CONCLUSIONS The results show that local skeletal muscle oxygenation is severely impaired during the initial 45 min of reperfusion after both 3 and 4 h of total muscle ischaemia with a slow-reflow phenomenon generally present, despite pronounced needs.