Impaired Airway Clearance

When mucus secretion and mucus clearance are not in balance, excessive airway mucus can cause serious problems. This condition is called impaired airway clearance.

Excess, often sticky mucus may accumulate in the airways in conditions as varied as cystic fibrosis, cerebral palsy, and chronic obstructive pulmonary disease bronchiectasis. Retained secretions are a universal problem in people with artifical airways (tracheostomies) or those who depend on assisted ventilation.

As a consequence of retained mucus, breathing becomes labored. More energy and effort are required to take in vital oxygen and to exhale carbon dioxide. Although underlying causes are diverse, consequences are the same: vulnerable individuals are caught up in the vicious cycle of recurrent, ever-worsening episodes of inflammation, pulmonary infection, increased production of excess mucus, and airway obstruction, lung damage, and respiratory failure.

People at risk for impaired airway clearance have one or more of the following problems:

Ineffective Ciliary Clearance

Normal cilia beat in a coordinated unidirectional fashion to mobilize mucus and clear particulate matter from the airways. Damaged or poorly functioning cilia perform this function inadequately or not at all.

Ciliary impairment is associated with conditions including:

  • Cystic fibrosis
  • Primary ciliary dyskinesia
  • Kartagener syndrome
  • Status post heart-lung or lung transplantation
  • Smoking or exposure to second-hand smoke

Excessive or Abnormal Mucus Production

Certain disorders and/or their treatments can cause excess mucus production and, in some cases, mucus that is abnormally thick and sticky. Large quantities of mucus, or mucus with altered physical properties, may overwhelm the mucociliary apparatus, inhibiting normal airway clearance.

Abnormal amounts of mucus with altered physical properties may imbe present in:

  • Cystic fibrosis
  • Bronchiectasis
  • Asthma
  • Chronic obstructive pulmonary disease (COPD), emphysema, chronic bronchitis
  • Mechanical ventilation

Impaired secretion clearance can occur as a result of any event or dysfunction that disrupts normal airway clearance mechanisms.

Ineffective Cough

Cough function may be weak or ineffective in diseases and conditions where:

Cough function is frequently impaired in:

  • Neuromuscular diseases, such as muscular dystrophy, spinal muscular atrophy, and multiple sclerosis
  • Neuromotor conditions including cerebral palsy, spinal cord injury, and severe traumatic brain injury
  • Individuals who depend on mechanical ventilation
  • Individuals who have received heart and/or lung transplants

Dysphagia/Aspiration/Gastroesophageal Reflux

Dysphagia, or difficulty in swallowing, is a consequence of anatomical abnormalities or weakness of the muscles associated with swallowing. Gastroesophageal reflux occurs when a defective lower esophageal sphincter allows stomach contents to surge backwards into the esophagus. Aspiration involves the inhalation of secretions, vomit, or foreign material into the lungs. Because saliva and gastric contents contain bacteria, aspiration introduces microorganisms into normally sterile airways.

Seizures

Seizures are disorders of cerebral function characterized by sudden, attacks of loss of consciousness and motor control. There is a risk of aspiration during seizures.

Conditions associated with dysphagia/aspiration/gastroesophageal reflux include:

  • Neurologic and neuromuscular disorders including cerebral palsy and muscular dystrophy
  • Seizures
  • Developmental delay
  • Disorders of the esophagus
  • Endotracheal intubation and tracheostomy

Immobility

Some individuals are unable to exercise because of diminished exercise capacity, neuromuscular weakness or neuromotor dysfunction. As a result, they cannot maintain adequate aerobic capacity, chest
bellows function, and lung volume.

Conditions associated with immobility include:

  • Spinal cord injury, quadriplegia
  • Severe cerebral palsy and/or developmental delay
  • Advanced muscular dystrophy, spinal muscular atrophy, severe spina bifida
  • Dependence upon assisted ventilation

Restrictive Lung Disease

Fixed or diminished lung volumes and vital capacities characterize restrictive lung disease. In conditions where respiratory muscles are weak or the spine and thorax are deformed, the ability to take a deep breath, to generate expiratory force, and to cough effectively are often affected.

Restrictive lung disease occurs commonly in:

  • Muscular dystrophy
  • Spina bifida
  • Spinal muscular atrophy
  • Severe cerebral palsy

Obstructive Lung Disease

Obstructive lung diseases include conditions where airway size is decreased as a result of structural changes, bronchospasm and/or excess mucus — limiting the ability to exhale.

Obstructive lung diseases include:

  • Bronchiectasis
  • Chronic Bronchitis
  • Alpha1-antitrypsin deficiency
  • Asthma
  • Cystic fibrosis
  • Primary ciliary dyskinesia
  • Kartagener syndrome

Learn more about airway clearance: