The cardinal signs of airway obstruction are:

• See-saw respiration
• Tracheal tug
• Airway noise
• Reduced movement of anaesthetic bag

Other signs may also be present, such as dis-coordinated respiration, increased respiratory rate, accessory muscle use and/or decreased breath sounds.

In children, the following may also be observed; head bobbing (infants), sternal recession, intercostal recession or subcostal recession.