TITLE:
Effects of Hyperventilation on Venous-Arterial Bicarbonate Concentration Difference: A Possible Pitfall in Venous Blood Gas Analysis
AUTHORS:
Akira Umeda, Kazuteru Kawasaki, Tadashi Abe, Tateki Yamane, Yasumasa Okada
KEYWORDS:
Hyperventilation; Bicarbonate; Bland-Altman Analysis; Venous Blood Gas Analysis
JOURNAL NAME:
International Journal of Clinical Medicine,
Vol.5 No.2,
January
24,
2014
ABSTRACT: Objectives: Recent
reports on venous blood gas analysis have shown that venous bicarbonate concentration is useful in the evaluation of the body acid-base status.
Most of these reports have been based on the Bland-Altman analysis comparing
arterial and venous blood gas values. We intended to elucidate any factors that
decrease the agreement between venous and arterial bicarbonate concentrations, which might impair the usefulness
of venous blood gas analysis. Methods: Healthy volunteers and patients with
various diseases (n = 141) were evaluated by simultaneous arterial and
venous blood sampling and Bland-Altman analysis. The venous-arterial bicarbonate concentration difference was compared between healthy volunteers and untreated respiratory
alkalosis patients. Intentional hyperventilation (30 or 60 breaths/min, for 3
min) was also performed on 6 healthy volunteers and the venous-arterial
bicarbonate concentration difference was evaluated. Results: The relative average bias in bicarbonate concentration was 2.00
mEq/l with venous bicarbonate higher
than arterial bicarbonate with 95% limits of agreement of ±4.15 mEq/l.
Hyperventilation challenges increased the venous-arterial bicarbonate concentration
difference in an intensity-dependent manner. The venous-arterial bicarbonate concentration
difference was higher in untreated respiratory alkalosis patients than in
healthy volunteers (P Conclusion:
Although venous bicarbonate may be useful to evaluate the body acid-base
status, hyperventilation increases the venous-arterial bicarbonate
concentration difference. Physicians should keep this phenomenon in mind.