Neural activities during replacement of blood with fluorocarbon emulsion

Exchange transfusion of the blood with fluorocarbon (FC) emulsion was conducted in the cat ventilated spontaneously with high oxygen tension gas, and responses of various neural activities to this replacement were studied. Animals survived in good physiological condition, at hematocrit values of less than 5%, more than 3 hours after the end of the FC transfusion. Electroencephalographic activity and afferent impulses of the carotid sinus nerve increased and sympathetic renal nerve activities decreased compared with the control activities before the replacement, indicating no impairment in the reflexogenic control of the respiratory and circulatory systems. Moreover, the amplitudes of the sensory evoked cortical potentials increased with lower hematocrit values during FC treatment. However, early components of auditory brain stem responses did not increase as markedly compared with the cortical responses. We concluded that the general condition of the animals and the neural responses examined were well preserved after FC emulsion exchange transfusion.