Normal capnographic waveforms

1) Normal trace in well controled asthma :

Typical rectangular wave pattern.

P2=0.24 %/sec (N<0.30) , DS=36.8 (N>30) FEV1=86% Pred

2) Capnography also allows reliable measurements in non-cooperative patients unsuited to forced spirometry.

Example of normal recording in a non-cooperative patients complaining of atypical breathlessness and exhibiting poor unreliable spirometric values.
Poor nasal permeability responsible for the fluttering of the alveolar plateau.
Normal capnographic measurements corroborate the clinical impression of absence of bronchospasm.

S2=0.29 (n<0.30), SD=37 (n>30) FEV1=62% Pred (non-valid)