Classic Shunt Equation
Compute the physiologic shunt fraction as the classic shunt equation Qs/Qt = (CcO2 - CaO2) / (CcO2 - CvO2).
Description
Compute the physiologic shunt fraction as the classic shunt equation Qs/Qt = (CcO2 - CaO2) / (CcO2 - CvO2).
Classic Shunt Equation is a focused biology tool that compute the physiologic shunt fraction as the classic shunt equation Qs/Qt = (CcO2 - CaO2) / (CcO2 - CvO2). It calculates locally from the values you enter and exposes the result without changing the source observations.1
When to use Classic Shunt Equation
Use Classic Shunt Equation when you need to compute the physiologic shunt fraction as the classic shunt equation Qs/Qt = (CcO2 - CaO2) / (CcO2 - CvO2). 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.
How Classic Shunt Equation calculates the result
The published tool contract uses this rule: Compute the physiologic shunt fraction as the classic shunt equation Qs/Qt = (CcO2 - CaO2) / (CcO2 - CvO2).
- Shunt fraction
- The calculated shunt fraction.
Limitations of Classic Shunt Equation
A ratio or percentage can conceal the scale of its numerator and denominator and becomes sensitive to measurement error when the denominator is small.
Alternative or Complementary measurements
Retain the original End-capillary O2 content, Arterial O2 content, and Mixed venous O2 content values and their units alongside the result. Shunt Fraction % is useful when you instead need to estimate the physiologic shunt fraction as (CcO2 - CaO2) / (CcO2 - CvO2) x 100, signed. Alveolar Gas Equation provides another view by helping you compute the ideal alveolar oxygen pressure PAO2 = FiO2 x (Patm - PH2O) - PaCO2 / R, with water vapour pressure defaulting to 47 mmHg at body temperature and respiratory quotient R defaulting to 0.8.
References
-
Pulmonary shunt — Wikipedia contributors
Similar or alternative tools
- Shunt Fraction %
Estimate the physiologic shunt fraction as (CcO2 - CaO2) / (CcO2 - CvO2) x 100, signed.
- Alveolar Gas Equation
Compute the ideal alveolar oxygen pressure PAO2 = FiO2 x (Patm - PH2O) - PaCO2 / R, with water vapour pressure defaulting to 47 mmHg at body temperature and respiratory quotient R defaulting to 0.8.
- Goldman Equation
Compute the Goldman-Hodgkin-Katz steady-state membrane potential at 37 degrees Celsius with the z=+1 cation form for potassium and sodium and inverted terms for chloride: VM = 61.5 x log10((pK x KOut + pNa x NaOut + pCl x ClIn) / (pK x KIn + pNa x NaIn + pCl x ClOut)) mV.