• Prevalence of dysfunctional breathing patterns in patients with difficult to control asthma compared with healthy volunteers [ Time Frame: 12/2010 ] [ Designated as safety issue: No ]
  

• 2. Prevalence of dysfunctional breathing patterns in patients with confirmed severe refractory asthma as defined by ATS criteria. [ Time Frame: 12/2010 ] [ Designated as safety issue: No ]
  

Hypothesis

Dysfunctional breathing patterns are more prevalent in patients with a diagnosis of difficult to treat asthma than healthy volunteers.

Design

This will be an open, prospective study, recruiting sequential patients admitted electively to undergo the difficult asthma protocol (DAP). These patients are generally admitted during a period of stability, but still have significant symptoms despite asthma therapy. Healthy volunteers will be recruited from hospital staff and their family and friends.

We will recruit patients over a 12 to 18 month period and hope to enrol 60 patients. On the final day of their 4 day admission, patients will be asked to wear the life vest from 0800hrs. During the morning they will undergo a 6 minute walk to test to assess their responses during exercise. They will also be reviewed by the supervising consultant to discuss the results of their investigations. While wearing the shirt, the patient will be asked to keep a diary of their activities and symptoms. The Life Shirt can be removed by the patient at the time of discharge.

20 Healthy volunteers will be recruited from the hospital staff. They will be asked to wear the life vest while undertaking their normal daily activities. They will also undertake a 6 minute walk test.

Tidal volume, minute volume and respiratory rate will be recorded at rest and during exertion, aided by the patient diary. Breathing pattern and features of dysfunctional breathing, such as frequent sighs, will also be noted. This will subsequently be correlated with the assessment of the supervising consultant with regard to the presence of dysfunctional breathing.

Data will also be analysed with regard to whether there are any differences between healthy volunteers, patients felt to have asthma, and those felt not to have asthma by their admitting consultant.