Fig. 5.

Effect of decreasing perfusate [either Krebs-Henseleit (KH) or perfluorocarbon (PFC)] oxygenation on cellular oxygenation, redox status, and cardiac function of left ventricular working hearts. A: during gradual perfusate deoxygenation, the myoglobin oxygen saturation decreases, indicated by a decrease in the fitted change in spectral optical density (ΔOD^*), and cytochromes (Cyt) a₆₀₅ and c become more reduced, indicated by an increase in ΔOD^*. Data for KH perfusion were normalized to their respective baseline. Data for PFC perfusion were normalized to the average change in ΔOD^* for data shown in Fig. 1A. KH: n = 6 and PFC: n = 7. B: effect of gradual perfusate deoxygenation on cardiac flow rates. With KH perfusion, aortic output dropped dramatically as soon as perfusate arterial oxygenation was lower than 90%. With PFC perfusion, aortic output was higher and better maintained. KH: n = 5 and PFC: n = 5. C: effect of gradual perfusate deoxygenation on heart rate. Heart rate was maintained at significantly higher levels with PFC perfusate at all levels of perfusate oxygenation. KH: n = 5 and PFC: n = 9. Data represent means ± SE.