Simulation of pursed-lips breathing by defined stenoses in pulmonary function diagnostics to quantify the effect of the pursed-lips breathing

Since many years it is recommended for COPD patients to reduce the crossdiameter of the lips in order to improve the exhalation by means of so-called pursed-lips breathing (PLB). But the effects have never been studied quantitatively. In this study, the PLB effect is simulated during lung function diagnostics, using different sized resistors inserted into the routine mouthpiece of the flow sensor to resemble the effective airway resistances of a PLB maneuver. This prospective, randomized study includes 20 healthy subjects and 50 COPD patients, who will perform lung function testing with 4 different sized resistors.

Inclusion Criteria:

Patients:

• COPD (GOLD I- IV)
• Stable respiratory situation that allows routine lung funtion
• capable of communication

Healthy:

• Lung Healthy
• capable of communication

Exclusion Criteria:

• Invasive Ventilation
• Other serious acute physical illnesses that require immediate intensive medical treatment
• Acute hypercapnic decompensation with a pH < 7.35 in the capillary BGA
• Pregnancy or Nursing
• Not able to give consent
• Not willing or able to follow the study protocol