Perflubron emulsion improves tolerance to low-flow ischemia in isolated rabbit hearts

The efficacy of the temporary oxygen carrier perflubron emulsion (PFC) in m aintaining oxygen delivery, tissue oxygenation, high-energy phosphates (HEP s), and myocardial function was investigated during low-flow ischemia. Perf usion rate, oxygen tensions, and cardiac function were measured during stab ilization (5 min), controlled-flow (22 ml/min x 20 min), and low-flow (0.22 ml/min x 120 min) periods in isolated rabbit hearts. Hearts were perfused with Krebs-Henseleit (KH) solution (Control), or 10 or 20% PFC (vol/vol; n = 8 per group) 5 min before and throughout the low-flow period. Myocardial tissue was then frozen for biochemical and metabolic measurements. Myocardi al oxygenation was measured at incremental flow rates by using 20% PFC (n = 4) or KH (n = 6). In PFC hearts, oxygen delivery and intramyocardial tissu e Po-2 were improved at all evaluated time points and flow rates, respectiv ely (p < 0.05). In Control hearts, left ventricular end-diastolic pressure was elevated at 60, 90, and 120 min of low-flow ischemia (p < 0.05), Tissue lactate was higher (p < 0.05) and HEPs lower (p < 0.05) in Control hearts during low-flow ischemia. These results indicate that PFC treatment improve s myocardial oxygenation, maintains HEPs, prevents ischemic contracture, an d may increase the margin of safety during low-flow ischemia in isolated ra bbit hearts.