Protection from cerebral air emboli with perfluorocarbons in rabbits

Cerebral air emboli have been implicated in the transient neurological deficits seen in patients after cardiovascular surgery. Since perfluorocarbon emulsions such as FC-43 have greater solubilities for gases compared to plasma, it was decided to investigate their potential in providing protection against transient ischemia produced by such emboli. Forty rabbits were divided into three groups of ten, twenty, and ten. They were anesthetized with acepromazine and ketamine and were given an infusion of either hetastarch or FC-43, 10 ml/kg i.v. In Group I, which received a bolus air injection into the internal carotid artery, survival rates were: 2/5 for the hetastarch group and 5/5 for the FC-43 group (p less than .05). In Group 2, which received an air infusion until the EEG was flat bilaterally, 3/10 hetastarch-treated rabbits survived while 10/10 FC-43-treated rabbits survived for 24 hours (p = .035). In Group 3, analysis of blood viscosity and osmolality over a four hour period following either hetastarch or FC-43 infusion resulted in no significant differences between the two treatments but a significant decrease in both variables after 30 minutes which returned to baseline values at 60 minutes. The results of the study demonstrate a protective effect from cerebral air emboli delivered into the internal carotid artery as either a bolus or slow infusion in rabbits pretreated with a perfluorocarbon emulsion in terms of survivability and recovery from transient neurological deficits.