ELECTROMETRIC SURFACE PH OF SKELETAL MUSCLE IN HYPOVOLEMIA

The measurement of skeletal muscle surface hydrogen ion activity was determined in a group of animals subjected to acute hemorrhages of 4C per cent of blood volume. After a period of two hours, reinfusion of the shed blood was performed and observation continued for two more hours. The results are compared with established indicators of tissue perfusion, including blood lactate concentration, blood pH, and arterial blood pressure. Skeletal muscle surface pH showed a steady decline throughout the hypovolemic phase of the experiment and returned to control levels after restoration of blood volume. The arterial blood lactate and blood pressure underwent lesser changes, whereas the arterial blood pH did not change significantly. The redox potential was also measured, but the results were inconclusive. These data allow the conclusion that measurement of the surface pH in skeletal muscle is a sensitive indicator of volume deficit, presumably reflecting increased anaerobiosis and lactic acidosis due to ischemia. © 1969.