This site is intended for healthcare professionals

Sign in
Go to /sign-in page

You can view 5 more pages before signing in

Blood gases and oxygenation

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

The normal range for PaO2 is 11.3-13.3 kPa. A partial pressure less than 8 kPa defines respiratory failure.

Arterial hypoxaemia is commonly due to pulmonary disease:

  • poor gas transfer:
    • type I respiratory failure
    • PaCO2 is typically low
  • hypoventilation:
    • type II respiratory failure
    • PaCO2 is typically raised

Arterial hypoxaemia may occur when the lungs are normal:

  • low inspired partial pressure of oxygen e.g. altitude
  • ventilation-perfusion mismatch
  • right to left shunts:
    • congenital heart disease
    • arteriovenous malformation of the pulmonary vessels

Measurement of the alveolar-arterial (A-a) gradient is useful in hypoxic patients and may help to distinguish hypoxaemia due to pulmonary disease from other causes of hypoxaemia.

Related pages

Create an account to add page annotations

Create a free account

Add information to this page that would be handy to have on hand during a consultation, such as a web address or phone number. This information will always be displayed when you visit this page

The content herein is provided for informational purposes and does not replace the need to apply professional clinical judgement when diagnosing or treating any medical condition. A licensed medical practitioner should be consulted for diagnosis and treatment of any and all medical conditions.

Connect

Copyright 2024 Oxbridge Solutions Limited, a subsidiary of OmniaMed Communications Limited. All rights reserved. Any distribution or duplication of the information contained herein is strictly prohibited. Oxbridge Solutions receives funding from advertising but maintains editorial independence.