Local capillary oxygen extraction ratio (O2ERc) versus regional capillary stopped-flow (%CDstop). In a 24-hour rat model of sepsis (cecal ligation and perforation [CLP]), capillary oxygen extraction from normally flowing capillaries (capillary velocity between 20 and 325 μm/s) was found to correlate with the degree of regional capillary stopped-flow. As capillary stopped-flow increased, the RBCs offloaded increased amounts of oxygen. (CLP group: y = 0.018x - 0.18; r2= 0.64; P < 0.05.) By permission from Am J Physiol Heart Circ Physiol 2002, 282:H156–H164 .