IMPEDANCE RECORDINGS TO DETERMINE CHANGE IN EXTRACELLULAR VOLUME IN THE BRAIN FOLLOWING CARDIAC-ARREST IN BROILER-CHICKENS

The present study describes a method to determine the onset and develo pment of brain damage in broiler chickens. Exsanguination disrupts the brain metabolism and causes the brain to become ischemic. Energy-requ iring systems in the cell membrane fail, which results in an ionic shi ft over the membrane, accompanied by a water influx into the cell. Thi s cellular edema decreases the extracellular volume of brain tissue. L n mammals, this brain damage has been measured by recording brain impe dance. We adapted this approach for use with poultry. Five to six-week -old commercial broilers were equipped with impedance recording electr odes in the striatum area of the brain. Cardiac arrest was induced by means of an intravenous injection of MgCl2 and brain impedance was rec orded for 30 min. The resulting curves showed a high similarity to tho se obtained in rats. No effects of 12 h antemortem feed deprivation on the size and rate of change in brain impedance could be found. Both i n anesthetized and conscious birds, a change in brain impedance was fo und. We conclude that brain impedance can be used to determine the dev elopment of ischemic brain damage in broiler chickens.