Clinical reliability of measured and calculated oxygen parameters in surgical patients: influence of hyperventilation.
The acid-base and oxygen status were assessed in patients undergoing abdominal surgery. We determined the measured and calculated parameters described by Siggaard-Andersen in arterial and mixed venous blood before, during and after a controlled hyperventilation. In these dynamic conditions, the mixed venous calculated p50 showed the most interesting variations. Derived values in arterial blood were unreliable since: 1) fitting to hyperbolic tangent function is not possible when SaO2 greater than 0.98; 2) in these patients, the arterio-venous difference in CtO2 is different from 2.3 mmol/L. The acute changes in calculated p50 are in agreement with the effect of hyperventilation on oxygen status.
Vaubourdolle
M
M
Laboratoire de Biochimie A, Hôpital Saint Antoine, Paris, France.
Beneteau-Burnat
B
B
Just
B
B
Lienhart
A
A
Giboudeau
J
J
D000005:Abdomen / Q000601:surgery; D001158:Arteries; D001784:Blood Gas Analysis / Q000592:standards*; D006801:Humans; D006985:Hyperventilation / Q000097:blood*; D016031:Liver Transplantation; D010100:Oxygen / Q000097:blood*; D012121:Respiration, Artificial; D013514:Surgical Procedures, Operative; D014680:Veins
D010100:Oxygen