Voice bubbling therapy for vocal cord dysfunction in difficult-to-treat asthma - a pilot study

Dysfunctional breathing often coexists with asthma and complicates asthma control, especially in difficult-to-treat asthma. Voice bubbling therapy (VBT) by a specialized speech therapist may influence the breathing pattern. This pilot study investigated the effect of voice bubbling therapy (VBT) in participants with difficult-to-treat asthma, who fulfilled criteria for dysfunctional breathing pattern.

Twenty-four patients were randomized between VBT and usual care (UC). VBT is blowing into a glass (resonance) tube (28 cm in length, 0.9 cm inner diameter) which ends in a bowl of water (1.5 litre). Lung function, capillary blood gas and questionnaires were measured at baseline, at 6 and 18 weeks of follow up.

No difference in ACQ and quality of life was found after VBT compared to UC group. However, after six weeks of bubbling therapy, pCO2 levels measured in capillary blood gas were higher (baseline median (IQR) pCO2 = 33.00 (17.25 - 38.6) mmHg; week 6 pCO2 = 36.00 (29.00 - 42.3) mmHg) p = 0.01. Moreover, ΔpCO2 (baseline - 18 weeks of follow up) was significantly correlated with ΔAQLQ (rs = 0.78, p = 0.02).

VBT in participants with difficult-to-treat asthma resulted in a higher average pCO2 level, indicating the treatment may improve hyperventilation. However, this did not improve asthma control or quality of life. VBT may have value for a better management of asthma related symptoms.