Preliminary investigations into the effects of breathing retraining techniques on end-tidal carbon dioxide measures in patients with asthma and healthy volunteers during a single treatment session

The results of these preliminary studies provide data to power larger studies. They suggest that ETCO2 rises during slow breathing in both asthma patients and healthy volunteers, and that this effect may persist beyond the intervention itself in healthy volunteers. The use of visual biofeedback had no effect on ETCO2 in healthy volunteers.