Background. Perfluorocarbon emulsion has proved beneficial in the prevention and amelioration of experimental air embolism. We examined whether the addition of perfluorocarbon to the prime solution could lead to a reduction in the incidence and severity of neurologic injury after the formation of a massive air embolism during cardiopulmonary bypass. Methods. Fourteen pigs underwent bypass in which either a crystalloid prime solution or a perfluorocarbon prime solution (10 mL/leg) was used. Ten minutes into bypass a bolus (5 mL/kg) of air or saline (control) was delivered via the carotid artery. The resulting cerebral infarcts were graded on the basis of the findings In triphenyltetrazolium chloride-stained cerebral sections, Colored microspheres were used to measure cerebral blood flow. Bitemporal electroencephalography was used to evaluate cerebral function. Results. Cerebral infarction was not found in the perfluorocarbon-air group (0 of 5 animals), as compared with its occurrence in 3 of the 5 animals in the crystalloid-air group. Cerebral blood flow was also maintained or increased in the perfluorocarbon-air group (p < 0.05), and the electroencephalogram total power showed less of a decrease and recovered more completely (p < 0.05) than it did in the crystalloid-air group. Conclusions. The addition of perfluorocarbon emulsion to the cardiopulmonary bypass prime solution leads to a reduction in the incidence and severity of neurologic injury after the formation of a massive air embolism during bypass. (C) 1997 by The Society of Thoracic Surgeons.