Correlative analysis of microcirculatory and cellular metabolic events in skeletal muscle during hemorrhagic shock

Skeletal muscle reactions to hemorrhagic shock were investigated in anesthetized cats (n = 23). The tenuissimus muscle was exposed for vital microscopy and shock was induced by single-withdrawal of 45% of the blood volume. Muscle microcirculation, energy metabolism and cell membrane potentials were followed over a 2 h period along with blood pressure, hematocrit and blood leukocyte, platelet, glucose, pyruvate and lactate contents. Bleeding usually caused complete cessation of muscle blood flow for 5--20 min, while the animal compensated the blood pressure. Reflex constriction occurred in medium-sized but not in terminal arterioles. When flow reappeared a marked maldistribution was evident in the capillary bed. Flow remained in 30--50% of the capillaries, permanently or intermittedly. Leukocytes could be found lodged in many arrested capillaries and also adhering to venules in large numbers. Erythrocyte or platelet plugs were not seen in the muscle microvasculature. Glucose and G6-P contents doubled and lactate increased 5-fold in muscle tissue during shock. CP was reduced by about 25% while the ATP-level remained unchanged. Membrane potentials declined 12% in shock and the spread in potentials from adjacent fibers increased.