PERFLUBRON EMULSION ADMINISTRATION DURING CARDIOPULMONARY BYPASS-PRELIMINARY RESULTS OF INCREASED CEREBRAL BLOOD FLOW

Abstract

Introduction. Advances in perfluorocarbon (PFC) technology have led to the development of improved 2nd generation O2 carriers such as perflubron emulsion.* Because perflubron emulsion has a high solubility coefficient for O2 and CO (2) and effectively releases O2 to tissue, its therapeutic application as a neuroprotectant during cardiopulmonary bypass (CPB) is being investigated. *(AFO 144; Alliance Pharmaceutical Corporation, San Diego, California) Methods. Following IRB approval and informed consent, 35 CABG patients were studied in 3 treatment groups: 1) Control (Normosol, 3 ml/kg, n = 10); 2) Low-Dose Perflubron (LDP, 3 ml/kg = 1.8 g/kg, n = 13); 3) High-Dose Perflubron (HDP, 2.7 g/kg, n = 12). At start of CPB, all groups underwent normovolemic hemodilution (2 units whole blood removed). Cerebral Blood Flow (CBF) was determined using133 Xe clearance (Initial slope index) at four time periods: 1) 5 mins. post start of CPB; 2) 10 mins. following administration of Normosol or Perflubron; 3) 10 mins. after cooling to 32[degree sign]C; 4) after rewarming to 36[degree sign]C. After an overall repeated measures test, ANOVA testing of group differences at each time period were done, adjusting for the effects of Hct & PaCO2, on CBF. Significance level was set at alpha = 0.05. Results. Baseline values for CBF, Hct, PaCO2, BP and temp. were similar in all groups. A significant overall perflubron emulsion effect on CBF was found (p = 0.0247). At time period 2, CBF increased 28.8% and 18.2% in the LDP and HDP group respectively, compared to 3.8% in the Control Group. CBF was significantly higher in the LDP Group than in the Control Group at all three time periods after administration. In the HDP group, CBF was higher than in the Control Group at periods 3 & 4. Discussion. In other studies, PFC-induced increases in CBF, especially to cortical gray matter, has been reported. [1,2] This is the first preliminary report of increased CBF in humans, resulting from a PFC administered during CPB. Since other influences on CBF (Hct, PaCO2, BP, temp.) have been controlled, we hypothesize that perflubron emulsion may have a local vasodilatory effect on cerebral vasculature. (Figure 1)Figure 1