Bohr Dead Space
Compute physiologic dead space with the Bohr equation: Vd = Vt x (PaCO2 - EtCO2) / PaCO2.
Description
Compute physiologic dead space with the Bohr equation: Vd = Vt x (PaCO2 - EtCO2) / PaCO2.
Bohr Dead Space is a focused biology tool that compute physiologic dead space with the Bohr equation: Vd = Vt x (PaCO2 - EtCO2) / PaCO2. It calculates locally from the values you enter and exposes the result without changing the source observations.1
When to use Bohr Dead Space
Use Bohr Dead Space when you need to compute physiologic dead space with the Bohr equation: Vd = Vt x (PaCO2 - EtCO2) / PaCO2. Enter Tidal volume, Arterial CO2 (PaCO2), and End-tidal CO2 (EtCO2) using the definitions and units below so the result can be reproduced.
- Tidal volume
- A finite measured or assumed value, expressed in mL.
- Arterial CO2 (PaCO2)
- A finite measured or assumed value, expressed in mmHg.
- End-tidal CO2 (EtCO2)
- A finite measured or assumed value greater than or equal to 0, expressed in mmHg.
How Bohr Dead Space calculates the result
The published tool contract uses this rule: Compute physiologic dead space with the Bohr equation: Vd = Vt x (PaCO2 - EtCO2) / PaCO2.
- Dead space volume
- The calculated dead space volume in mL.
Limitations of Bohr Dead Space
The calculation does not propagate measurement uncertainty, sampling error, or biological and chemical variability.
Alternative or Complementary measurements
Retain the original Tidal volume, Arterial CO2 (PaCO2), and End-tidal CO2 (EtCO2) values and their units alongside the result. Tidal Volume Estimate (Radford) is useful when you instead need to estimate tidal volume using the Radford approximation of 8 mL per kilogram of body weight. Bohr Effect Shift provides another view by helping you compute the Bohr effect shift of hemoglobin oxygen affinity as shiftLogP50 = phiBohrCoefficient x (pH2 - pH1), where phi is the signed Bohr coefficient, negative by convention and defaulting to -0.48 for human whole blood.
References
-
Dead space (physiology) — Wikipedia contributors
Similar or alternative tools
- Tidal Volume Estimate (Radford)
Estimate tidal volume using the Radford approximation of 8 mL per kilogram of body weight.
- Bohr Effect Shift
Compute the Bohr effect shift of hemoglobin oxygen affinity as shiftLogP50 = phiBohrCoefficient x (pH2 - pH1), where phi is the signed Bohr coefficient, negative by convention and defaulting to -0.48 for human whole blood.
- Total Blood Volume Estimate
Estimate total blood volume from body weight using the documented reference value of 70 millilitres per kilogram.