Central Venous-to-Arterial Blood Gas Research Estimates
Research estimates from CENTRAL venous specimens only, never peripheral venous blood. Not a substitute for directly measured arterial blood gas or oxygenation assessment.
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Estimated arterial values
Enter all three measurements and confirm the sample origin.
Separate univariate Treger et al. (2010) regressions, not a physiologic conversion model
No PaO₂ or SaO₂ is calculated. Observed agreement limits are NOT individual regression prediction intervals.
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Treger equations, source population and limits
Original study equations
Estimated arterial pH = −0.307 + 1.05 × central venous pH. Estimated PaCO₂ = 0.805 + 0.936 × central venous PCO₂. Estimated arterial HCO₃⁻ = 0.513 + 0.945 × central venous HCO₃⁻. Do not confuse these separate regressions with a multivariable model.
Hypothetical example
Central pH 7.40, PCO₂ 50 mmHg, HCO₃⁻ 24 mmol/L: estimated arterial pH 7.463, PaCO₂ 47.6 mmHg, HCO₃⁻ 23.2 mmol/L.
Population and limitations
Original 40 adult ICU participants and 190 sample pairs; generally collected within two minutes and analyzed on the same system. Bland–Altman limits of agreement concern observed arterial-minus-central venous differences, NOT prediction uncertainty of these regressions. Other patients, peripheral samples, PaO₂ and SaO₂ are outside scope. Method consistency and clinical interpretability require further review.
Source and approval
Sources compared 2026-11-10.