Is resuscitation from hemorrhagic shock limited by blood oxygen-carrying capacity or blood viscosity?
Systemic and microvascular hemodynamic responses to volume restoration from hemorrhagic shock were studied in the hamster window chamber model to determine the significance of blood rheological and oxygen transport properties. Moderated hemorrhage was induced by means of arterial controlled bleeding of 50% of the blood volume. The hypovolemic shock state was maintained for 1 h before resuscitation. The animals were resuscitated by infusion of 25% of blood volume using either fresh plasma or blood and were studied for 90 min. Transfusion was performed with either oxygen-carrying fresh red blood cells (RBCs) or non-oxygen-carrying RBCs whose hemoglobin was converted to methemoglobin (MetHb). Systemic parameters, including cardiac output, vital organ blood flow distribution, microvascular hemodynamics, and capillary perfusion (functional capillary density [FCD]), were measured during the resuscitation period. Fluorescent-labeled microspheres were used to measure organ blood flow (brain, h
