Skip to Main Content


This chapter will address Practice Pattern 6C of the Guide to Physical Therapist Practice: Impaired Ventilation, Respiration/Gas Exchange and Aerobic Capacity/Endurance Associated with Airway Clearance Dysfunction. As you may recall from the oxygen transport pathway (see Chapter 5, Physiology of the Cardiovascular and Pulmonary Systems), the ability to exchange oxygen and carbon dioxide is dependent on an unobstructed path from the upper airways to the lungs. Normally, pulmonary secretions are easily removed from the airways by the mucociliary escalator, clearing the way for gas exchange to occur. When a dysfunction exists in the airway clearance mechanism, the inability to remove pulmonary secretions may result in decreased oxygen carried to the circulatory system, resulting in impaired muscle performance and aerobic endurance.


This chapter provides a review of the anatomy and physiology of the pulmonary system and describes the pathophysiology of cystic fibrosis (CF), an obstructive lung disease. The components of physical therapy (PT) management via Practice Pattern 6C will be illustrated, using a case study of a patient with CF. The management of airway clearance dysfunction is integral to this patient population and will demonstrate the effects of this dysfunction on impairments in physical function. Threshold levels or factors that affect ventilation, airway clearance, activity, and musculoskeletal function will be described and matched to appropriate interventions. The International Classification of Functioning, Disability and Health (ICF) will be used to demonstrate the body functions and structures evident in CF and their relation to activity and participation. Finally, though research efforts in this area are ongoing, there are limits to our knowledge about the disease of CF and the PT management that is currently used. Future directions for discovery in the realm of CF are discussed.




The pulmonary system can be divided into two distinct categories: the musculoskeletal pump and a gas-exchanging organ.13 These components act in synchrony to achieve both ventilation and respiration. Whereas the pump is made up of the thorax and attaching muscles, gas exchange is carried out by the upper and lower divisions of the airways and associated components.


There are 23 generations or divisions of airways.2 The primary lobule or acinus consists of a transitional zone of bronchioles, alveolar ducts, and alveoli.2,4 Capillaries surround the alveoli for ease of gas exchange. The lungs are supplied with blood from the bronchial circulation (airways) and the pulmonary artery (alveoli).2,4 Gas exchange occurs by diffusion across the blood–gas barrier and follows the principles of Fick's law. Basically, the rate of gas transferred depends on the area of exchange, thickness of the area, and the partial pressure between the two sides.2 If the lung tissue was spread out over the ground, the total size of the area would be similar to that of a tennis court.2 The properties of the “gas” and tissue where the gas is being exchanged also ...

Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.


About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

AccessPhysiotherapy Full Site: One-Year Subscription

Connect to the full suite of AccessPhysiotherapy content and resources including interactive NPTE review, more than 500 videos, Anatomy & Physiology Revealed, 20+ leading textbooks, and more.

$595 USD
Buy Now

Pay Per View: Timed Access to all of AccessPhysiotherapy

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.