Breathing retraining for dysfunctional breathing in asthma: a randomised controlled trial

Functional breathing problems have been shown to result in significant morbidity including respiratory symptoms such as breathlessness, chest tightness and chest pain, and non-respiratory symptoms such as anxiety, light headedness, and fatigue. ^{1- 3} Because patients frequently overbreathe ¹ or have an increased respiratory rate, ⁴ this syndrome is often called the "hyperventilation syndrome". Nevertheless, patients may exhibit other breathing abnormalities such as unsteadiness and irregularity of breathing, ^{4- 6} frequent sighing, ^{2, 6} and a predominantly upper chest rather than diaphragmatic respiratory effort. ^{2, 3} Other diagnostic terms have been applied to patients with symptoms produced by abnormal breathing including "dysfunctional breathing". ⁷

Functional breathing disorders have been described in people with asthma and asthma-like symptoms. ⁸ Functional respiratory tract and vocal cord disorders in association with asthma have been reported as a cause of respiratory symptoms including wheeze, chest tightness and dyspnoea. ⁹ Symptomatic hyperventilation has been implicated as a factor in apparent steroid resistant asthma ¹⁰ and may complicate severe and brittle asthma. ¹¹ Patients with asthma-like symptoms but lacking objective evidence of asthma may hyperventilate when provoked by psychological or physiological stress, ¹² and symptomatic hyperventilation may cause symptoms in children diagnosed as having exercise induced asthma which does not respond to conventional treatment. ¹³ Dysfunctional breathing may, however, be responsive to interventions directed at breathing retraining; improvements have been reported in clinical series ^{14- 16} and in a randomised controlled trial. ¹⁷ We recently reported that one third of women and one fifth of men treated for asthma in a single general practice had symptoms suggestive of dysfunctional breathing, ¹⁸ and hypothesised that these patients would show clinically relevant improvements in their quality of life as a result of breathing retraining.

We report a randomised controlled trial comparing breathing retraining with asthma education (to control for non-specific effects of health professional attention) for asthmatic subjects in the community with symptoms suggestive of dysfunctional breathing.

METHODS

Subjects

Patients aged 17-65 years with a diagnosis of asthma who had received at least one prescription for an inhaled or oral bronchodilator or prophylactic anti-asthma medication in the previous year were identified from the medical records of a single semi-rural UK general practice of 7033 patients. They were sent and asked to return the...