Converting venous acid-base and oxygen status to arterial in patients with lung disease

The aim of the present study was to evaluate a method for calculating arterial values of pH, carbon dioxide tension (P(CO(2))) and oxygen tension (P(O(2))) from peripheral venous values. In total, 40 patients were studied. Arterial and peripheral venous blood were sampled at a department of respiratory diseases. Arterial values were calculated from venous, and measured and calculated values of arterial pH, P(CO(2)) and P(O(2)) were compared. Measured and calculated values of pH and P(CO(2)) correlated well, with the difference between them having a very small bias and standard deviation (pH -0.001+/-0.013, P(CO(2)) -0.09+/-0.28 kPa) within those considered acceptable for laboratory equipment and clinical practice. All but four patients had peripheral oxygen saturation (S(p,O(2)))