J. Bartels is the first named author of the 1954 primary study comparing respiratory dead space measurements using single-breath analysis of oxygen, carbon dioxide, nitrogen or helium. The journal supplies the initial-only byline; it does not establish a fuller personal name. The measurement contribution concerns the relationship between expired gas composition and expired volume.[ref]
The Respiratory Dead Space Measured by Single Breath Analysis of Oxygen, Carbon Dioxide, Nitrogen or Helium by J. Bartels and others. p. 41, primary byline, study title and opening measurement description
A single expired breath is not compositionally uniform. Conducting-airway gas appears before gas from exchanging regions, with a transition that depends on mixing and measurement response. Pairing mouth-flow recording with gas-fraction recording allows elapsed time to be converted into an expired-volume coordinate. Synchronization matters because a gas analyser can respond later than the flow sensor.
An original idealized washout curve makes the volume interpretation concrete. Suppose a tracer fraction is zero over the first 100 mL, rises linearly to its plateau over the next 100 mL, and then stays at a plateau value . The equivalent sharp-boundary volume under this flat-plateau model isThe transition contributes half its width. This synthetic equal-area construction explains a measurement principle; it is not a reported observation from Bartels's subjects.
A sloping plateau, incomplete tracer equilibration or analyser delay can change the inferred boundary. Comparing tracers therefore tests a physiological measurement model as well as an instrument. Bartels's verified authorship belongs to that gas-analysis experiment, without claiming that the initial-only name identifies a particular namesake or that every definition of respiratory dead space gives an identical volume.
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