respiratory failure

Respiratory failure is a term to denote when the respiratory system fails in one or both of its gas exchange functions: oxygenation and carbon dioxide elimination. This results in arterial oxygen and/or carbon dioxide levels being unable to be maintained within their normal range. While it is not directly a radiological topic, it is useful to understand its general concepts.

Pathology

It can arise from a fault in any of the components of the respiratory system, and can, therefore, involve a problem in airways (trachea-bronchi), alveoli, central nervous system (CNS), peripheral nervous system (PNS), respiratory muscles, and chest wall.

Classification

It is broadly divided into two main subtypes:

• type I respiratory failure (hypoxic): there is hypoxia without hypercapnia and ventilation is usually not compromised
  • caused by mechanisms such as
    • lung parenchymal disease
    • diseases of vasculature and shunts
      • right-to-left shunts
      • pulmonary embolism
    • interstitial lung diseases
      • ARDS
      • pneumonia
      • emphysema
• type II respiratory failure (hypercapnic): results from inadequate ventilation; both oxygen and carbon dioxide are affected 
  • caused by conditions such as
    • increased airways resistance
      • asthma
      • suffocation
    • reduced breathing effort 
      • medication effects
      • brainstem lesions
    • neuromuscular conditions 
      • Guillain Barre syndrome
      • myasthenia gravis
      • motor neuron disease
    • mechanical restriction 
      • thoracic deformity: kyphoscoliosis
      • thoracic rigidity: ankylosing spondylitis
      • flail chest

Siehe auch:

• Morbus Bechterew
• flail chest
• Guillain-Barré-Syndrom