IV PERFLUBRON EMULSION VERSUS AUTOLOGOUS TRANSFUSION IN SEVERE NORMOVOLEMIC ANEMIA - EFFECTS ON LEFT-VENTRICULAR PERFUSION AND FUNCTION

Intact cardiac compensatory mechanisms are necessary to maintain adequ ate tissue oxygenation during acute normovolemic hemodilution (ANH). L eft ventricular (LV) perfusion, oxygenation and function were analyzed in an experimental whole-body model of profound ANH (Hct 9%) and effe ctiveness of a perfluorocarbon-based oxygen carrier in maintaining myo cardial oxygenation and function was evaluated. A total of 22 anesthet ized dogs were hemodiluted to Hct 20% followed by a simulated, control led blood-loss phase in which dogs were randomized to either: (1) 1:1 exchange of lost blood with autologous red blood cells (RBC-group), (2 ) 1:1 exchange with a colloid (control-group) and (3) 1:1 exchange wit h a colloid after a single dose of 1.8 g/kg BW perflubron iv (PFC-grou p). Myocardial oxygen delivery and consumption as well as endocardial perfusion were determined using radioactive microspheres. LV myocardia l contractility (LV MC) was assessed from: (1) the relationship betwee n maximum rate of LV pressure increase (LVdp/dt(max)) and LV enddiasto lic volume (LVEDV) and (2) analysis of the LV endsystolic pressure vol ume relationship (ESPVR). LV diastolic properties were reflected by (1 ) minimum rate of LV pressure increase (LVdp/dt(min)), (2) slope and i ntercept of the enddiastolic pressure-volume relationship (EDPVR) and (3) the time-constant of isovolumic LV pressure decline ''tau 1/2''. F ull sets of LV MC data were obtained from 18 dogs (n=6 per group). LV MC (LVdp/dt(max)-LVEDV relation) increased after perflubron administra tion. At the lowest Hct level, all parameters reflecting LV MC as well as LVdp/dt(min) were significantly higher in the PFC-group than in th e control-group. After profound normovolemic hemodilution (Hct 9%) sup eriority of LV MC and LV diastolic properties was found, when myocardi al oxygenation was supported by iv perflubron emulsion, a temporary O- 2 carrier.