LAUSR

Introduction: Liposome-encapsulated hemoglobin vesicles (HbVs) can serve as a blood substitute with human blood. Method: To investigate the resuscitation effect of HbVs on lethal hemorrhage and their efficacy for decreasing myocardial arrhythmogenesis, optical mapping analysis (OMP) and an electrophysiological study (EPS) were performed in graded 85% hemorrhage in rats in both acute and chronic phase. Six rats were resuscitated by intraosseous infusion of 5% albumin solution (ALB group), while 6 rats by washed rat erythrocytes (wRBC group) and 6 rats by HbVs (HbV group). Survival effects over 24 hours were examined in > 10 rats in each group. After excising the heart, OMP and an EPS were performed. Results: All rats died in ALB group, whereas all survived subsequent 24 hours in wRBC group and HbV group. In acute phase, OMP showed impaired (prolonged) action potential duration dispersion (APDd) in left ventricle in ALB group. In contrast, myocardial APDds in left ventricle were substantially attenuated in HbV group and wRBC group. Lethal arrhythmias (ventricular tachycardia [VT] or ventricular fibrillation [VF], VT/VF) were provoked by EPS in ALB group. No VT/VF was induced in both wRBC group and HbV group. In chronic phase of two weeks after the resuscitation, OMP and an EPS were performed again in excising the heart. Anti-arrhythmic effects were confirmed by normal OMP findings (Normal APDd) and No VT/VF induced as shown in Figure. Conclusions: Lethal hemorrhage causes VT/VF in the presence of impaired APDd. Intraosseous HbVs infusion acutely rescues lethal hemorrhage through preventing lethal arrhythmias with preserved APDd. These effects were preserved in chronic phase.