physiologic dead space

noun5

1. •
   That volume of air in the lung which does not partake in gas exchange.
2. •
   That volume of air in the lung that does not eliminate carbon dioxide, as defined functionally by the Bohr equation.

   • Bohr's method measures the volume of the lung which does not eliminate CO₂. Because this is a functional measurement, the volume is called the physiologic dead space. — 2011
3. •
   The sum of the anatomic plus the alveolar dead spaces.
4. •
   The sum of the parallel and the serial dead spaces.
5. •
   (no longer used) The volume of the conducting airways of the lung. This definition became inadequate once the alveolar dead space was described.

   • Throughout this paper, the term physiological dead space will be used to refer to the volume of the conducting airway down to the location at which a large change in gas composition occurs. — 1948