Use Shunt Fraction % when you need to estimate the physiologic shunt fraction as (CcO2 - CaO2) / (CcO2 - CvO2) x 100, signed. Enter End-capillary O2 content, Arterial O2 content, and Mixed venous O2 content using the definitions and units below so the result can be reproduced.

End-capillary O2 content

A finite measured or assumed value, expressed in mL/dL.

Arterial O2 content

A finite measured or assumed value, expressed in mL/dL.

Mixed venous O2 content

A finite measured or assumed value, expressed in mL/dL.

The published tool contract uses this rule: Estimate the physiologic shunt fraction as (CcO2 - CaO2) / (CcO2 - CvO2) x 100, signed.^[1]

Shunt fraction

The calculated shunt fraction in %.

The output is an estimate tied to the stated model and coefficients; it is not a direct measurement and should retain that label when reported.

Retain the original End-capillary O2 content, Arterial O2 content, and Mixed venous O2 content values and their units alongside the result. Classic Shunt Equation is useful when you instead need to compute the physiologic shunt fraction as the classic shunt equation Qs/Qt = (CcO2 - CaO2) / (CcO2 - CvO2). Gap Fraction % provides another view by helping you compute canopy gap fraction as a percentage of sky-visible pixels over total hemispherical image pixels.

• Classic Shunt Equation

  Compute the physiologic shunt fraction as the classic shunt equation Qs/Qt = (CcO2 - CaO2) / (CcO2 - CvO2).

• Gap Fraction %

  Compute canopy gap fraction as a percentage of sky-visible pixels over total hemispherical image pixels.

• S Phase Fraction

  Compute the fraction of cells in S phase relative to the total counted cell population.