Hemoglobin saturation is the extent at which hemoglobin binds with the oxygen. This relationship of oxygen and hemoglobin is shown by oxygen hemoglobin dissociation or saturation curve. When there is obstruction in the right pulmonary bronchus, the affinity of hemoglobin with oxygen will be reduced. This condition will cause shifting of oxygen hemoglobin saturation curve towards right. For more details, visit this Link.