blood gases in pink puffers
Last reviewed 01/2018
hyperventilation with poor gas exchange
- PIO2 = 20
- PaO2 = 8
- PaCO2 = 3.5
- PIO2 - (PaO2+PaCO2) = 8.5
normal:
- PIO2 = 20
- PaO2 = 13.3 (12-14)
- PaCO2 = 5.3 (5-6)
- PIO2 - (PaO2+PaCO2) = 1.4 (less than 2.5)
This is a situation caused by parenchymal lung disease in which there is a poor gas exchange. The overactive stimulation to breathe comes not from the PaCO2, which is low, but is probably a result of stimulation of J receptors in the lung - i.e. it is a neurogenic phenomenon.
A similar picture develops in asthma, this time in an airways disease as a result of stimulation of irritant receptors.