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Signs of respiratory failure

Overall look

The patient is usually pale, sweaty, clammy and looks terrified, exhausted or obtunded

Most patients with respiratory failure sit up unless the cause of respiratory failure is CNS related

Respiratory rate

< 8 or > 30 /min (slow respiratory rate in association with fatigue is an ominous sign)

interrupted speech (cannot finish sentence)

Pulse rate

Tachycardia is usually associated with respiratory failure

Bradycardia is usually a late and sinister sign

SpO2 < 88%

This roughly corresponds to a PaO2 of 8 KPa although the variability is wide

Confusion, agitation or convulsions

Usually caused by hypoxia and can put the patient and staff at risk of injury

Reduction in level of consciousness

Usually associated with hypercapnia or severe hypoxia

Chest signs

Looking at the patient's chest movements (or lack of) is crucial. Look for:

  • prolonged expiratory phase (wheeze)
  • use of accessory muscles of respiration
  • in drawing of suprasternal notch (airway obstruction)
  • see-saw respiratory pattern (airway obstruction or exhaustion)

systematic chest examination is described elsewhere


Don't forget to examine the cardiovascular system as heart failure is a common cause of respiratory failure.

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