Medicine of the Future in America

The Oxyhemoglobin Dissociation Curve in Liver Cirrhosis

The Oxyhemoglobin Dissociation Curve in Liver CirrhosisTwo indexes characterize the oxyhemoglobin dissociation curve (ODC): shape and position. The latter index is usually described by the Po2 at half-saturation of hemoglobin (P50). Historically, the first factors found to be able to influence hemoglobin affinity for oxygen were salts studied in hemoglobin solutions. Anions, such as chloride or inorganic phosphates, induce a right shift of the ODC that enhances tissue oxygenation, whereas cations such as sodium, potassium, or magnesium have an opposite effect.

Before 1967, four groups of authors studied some parts of the ODC of cirrhotic patients by measuring a few Po2/oxygen saturation percentage (So2%) points in each curve: two articles, reported normal values, whereas the others showed a rightward shift of the ODC. In 1967, two groups of authors, showed that in RBCs, the organic phosphate 2,3-diphosphoglycerate (2,3 DPG) plays a major role in regulating the position of the ODC, although inorganic phosphates play a minor, but not negligible, role in this regard. A 1974 review article did not discuss the effects of ions on hemoglobin but considered that only four factors were able to influence the position of the ODC: pH, body temperature, carbon dioxide content, and organic phosphates. Subsequently, other authors observed an increase in 2,3 DPG and P50 of cirrhotic patients. Unfortunately, the number of subjects was small in one group, while some series, included not only cirrhotics but patients with other liver diseases.
Plasma ions were not measured. Finally, the position of the ODC was characterized by P50 instead of the whole ODC, which would have given much more information. In short, all articles except two> reported a rightward shift of the ODC in cirrhotic patients. Nevertheless, in vivo25-27 and in vitro–29 data confirmed that ions play a role in regulating the position of the ODC. The aim of the present work was to measure the entire ODC in whole blood in a homogeneous group of patients with cirrhosis, all of whom were candidates for an orthotopic liver transplantation (OLT).

This entry was posted in Liver disease and tagged liver cirrhosis, oxyhemoglobin dissociation curve.
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