How to recognise partial versus complete airway obstruction, when to intervene and when not to, and how to manage a partially obstructed airway until emergency help arrives.
The correct response to choking depends critically on one distinction: whether the airway is partially or completely obstructed. These two situations require different responses, and responding to a partial obstruction as if it were complete — by immediately attempting back blows and abdominal thrusts — can actually worsen the situation by dislodging a partial obstruction and converting it into a complete one.
Understanding the difference and knowing the correct management for each is essential first aid knowledge.
| Feature | Partial Obstruction (Mild) | Complete Obstruction (Severe) |
|---|---|---|
| Can speak | Yes — may be difficult but possible | No |
| Can cough | Yes — cough is forceful | No effective cough; or silent |
| Breath movement | Some air movement audible | Little or no air movement |
| Colour | Normal or slightly anxious | Progressively blue (cyanosis) |
| Response to asking "are you choking?" | Can respond verbally | Nods; unable to speak |
| Appropriate response | Encourage coughing | Back blows + abdominal thrusts |
⚠️ If the person can cough forcefully, do not intervene with back blows or abdominal thrusts. Encourage them to keep coughing. The cough is the most effective method to clear an airway obstruction — an effective cough generates airway pressures exceeding those achievable with back blows. Premature intervention can move the object further or convert a mild obstruction into a severe one.
Partial obstructions arise from:
| Cause | Examples |
|---|---|
| Food bolus | Piece of food partially obstructing the airway |
| Foreign body | Small object, especially in children |
| Oedema (swelling) | Allergic reaction, angioedema, burn |
| Infection | Epiglottitis, croup, tonsil abscess |
| Secretions | Thick mucus from infection or neurological condition |
| Tumour | Laryngeal or tracheal tumour — gradual onset |
| Laryngospasm | Sudden reflex closure of the vocal cords |
Non-food causes of partial obstruction — swelling, infection, tumour — require medical investigation and cannot be cleared by first aid techniques. The management of these is described below.
When the person can cough effectively:
If coughing continues without clearing the obstruction:
Transition point: When coughing becomes silent, weak, or the person shows signs of distress (clutching throat, blue lips, inability to speak), move to the severe obstruction protocol immediately:
Throat and airway swelling from allergic reaction can cause rapidly progressing partial obstruction:
A barking cough and stridor (high-pitched breathing sound) in a child, typically under 5:
Severe throat infection causing sudden swelling of the epiglottis (the flap covering the airway):
When emergency services arrive or when calling 999 for partial obstruction:
| Situation | Response |
|---|---|
| Coughing forcefully, can speak | Encourage coughing; do not intervene |
| Cough weakening, cannot speak | Start back blows and abdominal thrusts; call 999 |
| Cannot cough or speak | Severe obstruction — back blows and abdominal thrusts immediately |
| Throat swelling (allergy) | Epinephrine if available; call 999; not a foreign body |
| Croup (child, barking cough) | Keep calm; upright; call 999 if stridor at rest |
| Epiglottitis (severe sore throat + drooling) | Call 999 immediately; keep upright; do not examine throat |
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