Relationship of appearance of abnormal plasma hemin pigment to development of irreversible hemorrhagic shock in dogs

Irreversible hemorrhagic shock in dogs was associated with a progressive rise in plasma hemoglobin levels and the appearance of an abnormal hemin pigment in the plasma. Both findings were related to mucosal necrosis of the bowel occurring as a result of prolonged hemorrhagic shock. In dogs perfused through the superior mesenteric artery during hemorrhagic shock, the bowel remained normal, irreversibility was prevented and the abnormal plasma findings did not occur.

Oxygen dissociation curves of mammalian blood in relation to body size

Oxygen dissociation curves were determined in mammalian blood at the CO2 tension of the organism, without the addition of buffers, dilution of the blood, or other alterations. It appears that the dissociation curve is related to body size in such a way that the blood of smaller animals has a higher unloading tension for oxygen. This finding is discussed in relation to the higher metabolic need for oxygen of the smaller animal. It is suggested that, in addition to the higher capillary density in the small animal, a higher unloading tension for oxygen also contributes to the steepness of the diffusion gradient for oxygen from the capillary to the tissue cells.