Causes of respiratory failure

Several past paper SAQs demand the candidate either generate a list of differentials (such as the diferentials for a diffuse pulmonary infiltrate) or define a sensible approach to the assessment of acute respiratory failure.

• Question 4  from the second paper of 2012 (a tracheostomy patient short of breath)
• Question 15.2 from the second paper of 2012 (a patient undergoing radiotherapy)
• Question 28 from the first  paper of 2010 (a post-op trauma patient)
• Question 28 from the second paper of 2005 (COPD)
• Question 2b from the first  paper of 2004 (PE)

This is a very artificial list of causes and investigations. It has been derived from the excellent UpToDate topic, "Evaluation of the adult with dyspnea in the emergency department".

In the post-op trauma patient, the list would consist of the following:

• Vascular/embolic causes:
  • Fat embolism
  • Pulmonary thromboembolism
  • Pulmonary oedema due to MI
• Infectious causes:
  • Aspiration pneumonia
• Drug-associated causes:
  • Opiate-associated respiratory depression
• Iatrogenic causes:
  • ETT maplosition
  • TRALI
  • Atelectasis
  • Resuscitation-associated fluid overload
• Autoimmune causes
  • Anaphylaxis
• Traumatic causes
  • Pneumothorax
  • Cardiac tamponade
  • Pulmonary contusions