Oxygen affinity in the blood of sheep.

The oxygen affinity in the blood of adult Dorset sheep with HbB was studied by determining several oxygen equilibrium curves under different conditions of pH and PCO2 by a method that allowed strict control of pH, PCO2, and HCO3- concentration over the entire curve. Nomograms and equations were derived that allowed the estimation of the oxygen saturation in a sample of blood in the range 0 to 100%, either from pH, PCO2 and PO2, or from PO2 and known P50. The advantage of this approach is that no assumptions about the shape of the oxygen equilibrium curve need be made (i.e. the Hill parameter, n, is not required to be constant), since the entire curve was measured.