Medicine of the Future in America

The Oxyhemoglobin Dissociation Curve in Liver Cirrhosis: Materials and Methods

We examined two groups of 50 subjects: one group of patients with cirrhosis (27 men and 23 women), all candidates for OLT, and one group of 50 gender-, age-, and height-matched control subjects. Mean age ± SD was 54 ± 7 years in the cirrhotic patients and 53 ± 8 years in the control subjects (not significant [NS]). Mean height was 1.72 ± 0.05 m in cirrhotic patients and 1.74 ± 0.06 m in normal subjects (NS). All subjects were lifelong nonsmokers or ex-smokers since at least 5 years of age. Criteria for diagnosis and liver serobiochemistry followed routine clinical methods. The origin of cirrhosis was as follows: cryptogenetic (n = 12), alcoholic (n = 7), postviral type B or C (n = 20), and primary biliary cirrhosis (n = 11). Four patients had a Child-Pugh score A, 20 patients had a score B, and 26 patients had score C. Ascites was present in 26 cirrhotic patients. Twenty-two cirrhotic patients were treated with spironolactone, and the other 4 patients received furosemide. Ten patients received propranolol for prophylaxis of digestive bleeding due to portal hypertension.

Due to the occurrence of severe hemodynamic complications in the early experience of our OLT surgical group, we performed a complete hemodynamic investigation with agreement of the local ethics committee and informed consent of the patients. We therefore had the opportunity to sample and analyze mixed venous blood from the pulmonary artery. The entire ODC on whole blood was traced under standard conditions (pH 7.40; Pco2, 40 mm Hg; temperature, 37°C) and corrected to the ODC in vivo by using actual values of pH, Pco2, and temperature. The method has been described previously. The advantage of this method is to describe the ODC at all levels of oxygen saturation and thereby to give the resulting function of oxygen loading and unloading. Briefly, 10 mL of blood was sampled and tonometered with a reducing gas mixture (5.6% carbon dioxide in pure nitrogen); the entire ODC was then measured by a dynamic process by introducing a second gas mixture (5.6% carbon dioxide in pure oxygen).

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