Acute Normovolemic Hemodilution

Isovolemic hemodilution down to hematocrit values of 10% has been performed in splenectomized dogs during pentobarbital anaesthesia. Circulatory changes were followed in the systemic circulation; for the estimation of capillary flow and capillary transport in skeleteal muscle a double isotope technic has been applied. Progressive hemodilution resulted in a significant increase of cardiac output and skeletal muscle flow; peripheral resistance decreased clearly parallel with the whole blood viscosity as measured at different shear rates. The transport capacity (PS) in skeletal muscle was not significantly changed. From this finding and from the lack of changes in the local effluent blood it is concluded that hypoxia does not occur when limited hemodilution is performed normovolemically. These data, therefore, add further support to the concept of limited hemodilution as a therapeutic tool in microcirculatory disorders.