• ‘posterior displacement of the tongue caused by reduced muscle tone’
• ‘soft palate and the epiglottis’
• vomit
• blood
• ‘swelling of the airway (e.g. anaphylaxis)’
• ‘foreign body’
• ‘laryngeal spasm’

(Gregory & Mursell, 2010: 2)

Gregory, P. and Mursell, I. (2010) Manual of Clinical Paramedic Procedures, Sussex: John Wiley & Sons