Respiratory failure

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Respiratory Failure
Classification and external resources
ICD-10J96
ICD-9518.81
DiseasesDB6623
eMedicinemed/2011
MeSHD012131
 
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Respiratory Failure
Classification and external resources
ICD-10J96
ICD-9518.81
DiseasesDB6623
eMedicinemed/2011
MeSHD012131

Respiratory failure is inadequate gas exchange by the respiratory system, with the result that levels of arterial oxygen, carbon dioxide or both cannot be maintained within their normal ranges. A drop in blood oxygenation is known as hypoxemia; a rise in arterial carbon dioxide levels is called hypercapnia. The normal reference values are: oxygen PaO2 more than 80 mmHg (11 kPa), and carbon dioxide PaCO2 lesser than 45 mmHg (6.0 kPa). Classification into type I or type II relates to the absence or presence of hypercapnia respectively.

Types[edit]

Type 1[edit]

Type 1 respiratory failure is defined as hypoxemia without hypercapnia, and indeed the PaCO2 may be normal or low. It is typically caused by a ventilation/perfusion (V/Q) mismatch; the volume of air flowing in and out of the lungs is not matched with the flow of blood to the lungs. The basic defect in type 1 respiratory failure is failure of oxygenation characterized by:

PaO2decreased (< 60 mmHg (8.0 kPa))
PaCO2normal or decreased (<50 mmHg (6.7 kPa))
PA-aO2increased

This type of respiratory failure is caused by conditions that affect oxygenation such as:

Type 2[edit]

Hypoxemia (PaO2 <8kPa) with hypercapnia (PaCO2 >6.0kPa).

The basic defect in type 2 respiratory failure is characterized by:

PaO2decreased (< 60 mmHg (8.0 kPa))
PaCO2increased (> 50 mmHg (6.7 kPa))
PA-aO2normal
pHdecreased

Type 2 respiratory failure is caused by inadequate alveolar ventilation; both oxygen and carbon dioxide are affected. Defined as the build up of carbon dioxide levels (PaCO2) that has been generated by the body but cannot be eliminated. The underlying causes include:

Treatment[edit]

Mechanical Ventilator

Emergency treatment follows the principles of cardiopulmonary resuscitation. Treatment of the underlying cause is required. Endotracheal intubation and mechanical ventilation is required in severe respiratory failure (PaO2 less than 50 mmHg). Respiratory stimulants such as doxapram are rarely used, and if the respiratory failure resulted from an overdose of sedative drugs such as opioids or benzodiazepines, then the appropriate antidote such as naloxone or flumazenil will be given.

See also[edit]

References[edit]

  1. ^ a b Burt, Christiana C.; Arrowsmith, Joseph E. (1 November 2009). "Respiratory failure". Surgery (Oxford) 27 (11): 475–479. doi:10.1016/j.mpsur.2009.09.007.