Asthma attacks

The following are examples of capnographic waveforms recorded during different escalating bronchospasms.

• NB : successive versions of the software were used ; certain scales had to be resized to become visually comparable. This explains why the traces show a few differences in appearance.

PEF (l/min), S2 (%.sec^-1) and PetCO2 (%) values are indicated for each recording.

Infra-clinical hypocapnic bronchospasm  

PEF=440 , P2=0.31, PetCO2=4.2

Slight bronchospasm

PEF=400 , P2=0.58, PetCO2=5.5

Marked bronchospasm

 
PEF=290 , P2=0.77, PetCO2=5.1

Serious bronchospasm

PEF=200, P2=0.92 , SD=8.5, PetCO2=5

Severe hypercapnic bronchospasm

PEF=110 , P2=1.14, SD=7.8, PetCO2=5.9
Both alveolar plateau steepness and PetCO2 confirm severe hypercapnea (>>6) .