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 ranges. While it is not directly a radiological topic, it is useful to understand its general concepts.
Pathology
Respiratory failure may arise from a fault in any of the components of the respiratory system, and can, therefore, involve a problem in the lower airways (trachea-bronchi), alveoli, central nervous system (CNS), peripheral nervous system (PNS), respiratory muscles, and/or 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
-
diseases of vasculature and shunts
pulmonary embolism
-
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
suffocation
-
reduced breathing effort
medication effects
brainstem lesions
-
neuromuscular conditions
-
mechanical restriction
thoracic deformity: kyphoscoliosis
thoracic rigidity: ankylosing spondylitis
-
-