PHENOXYBENZAMINE—A MEDIATOR OF BLOOD OXYGEN AFFINITY

Studies of the effect of phenoxybenzamine on oxygen transport have been concentrated on flow and resistance changes. Previous studies have ignored the possible effects of phenoxybenzamine on the ability of red blood cells to offload oxygen itself. After an initial inhibitory effect phenoxybenzamine greatly enhances the ability of the red cell to offload oxygen under conditions seen at the tissue level. The disparity between P50std and organic phosphate changes found in this and other studies warrants extreme caution to be used in interpreting results where P50 itself is not measured.