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Acute Respiratory Failure

Respiratory failure results from inadequate gas exchange by the respiratory system, meaning that the arterial oxygen, carbon dioxide or both cannot be kept at normal levels. A drop in the oxygen carried in blood is known as hypoxemia; a rise in arterial carbon dioxide levels is called hypercapnia. Respiratory failure is classified as either Type I or Type II, based on whether there is a high carbon dioxide level.

Respiratory failure usually includes:

  • Increased respiratory rate
  • Abnormal blood gases (hypoxemia, hypercapnia, or both)
  • Evidence of increased work of breathing.


  • Shortness of breath
  • Cyanosis (a blue tint to the skin, mostly around the mouth, eyes and nails)
  • Rapid heart rate
  • Wheezing or coughing
  • Bad headache
  • Pulmonary hypertension