The effect of hyperchylomicronaemia on oxygen affinity in human blood.

Evidence for a leftward shift of the oxygen dissociation curve in HC patients was first described by Ditzel and Dyerberg. These results were challenged by Robertson et al., who saw no shift using a different technique to obtain P-50. Both methods are open to possible errors. In order to clarify the mechanism whereby HC blood shows an increased affinity for O2, the method of Longmuir and Chow was used since it is unaffected by these problems. Exposure of blood to various lipid emulsions was shown to exhibit a slow fall in pO2 due to increased binding of oxygen to haemoglobin. During the same period the pH difference across the cell membrane is largely abolished. As a result the oxygen dissociation curve is displaced to the left by the Bohr shift. This is an acute and dramatic event. We postulate that this increased affinity of red blood cells for O2 may predispose patients in the HC state to myocardial ischaemia by this mechanism.