Figure 8

Radioactivity. Mean amount of radioactivity in the carotid artery at each sampling time, as a measure of the amount of emboli passing through the pulmonary circulation. The first dashed line indicates the infusion of shed blood surrogate. The second dashed line indicates the infusion of epinephrine and Ringer's lactate. The horizontal line denotes the baseline value calculated from the two samples taken before infusion.