see also:

• stridor
• wheeze
• noisy breathing
• snoring
• obstructive sleep apnoea (OSA)
• Stridor vs Wheeze vs Stertor and snoring in children (pdf)

• noise during breathing can be of various types depending upon whether awake or asleep and on where the airway obstruction arises
• stertor is primarily an inspiratory noise arising from the upper airways and in the unconscious patient, it generally indicates upper airway obstruction and potentially impending death caused by the tongue which requires airway management such as lying on the side, jaw thrust, chin lift, etc.
• stertor also includes snoring and nasal obstruction sounds such as adenoid hypertrophy.

• obstructed upper airway in the unconscious patient
• snoring
• nasal obstruction
  • adenoid hypertrophy
  • congested nose / rhinitis
  • nasal polyps
  • retropharyngeal_abscess
  • cranio-facial abnormalities
• oropharyngeal obstruction
  • enlarged tonsils / tonsillitis
  • enlarged tongue / angioedema
  • cranio-facial abnormalities