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This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
Key points
- Mild obstruction: patient can cough, speak, breathe → encourage coughing. Do NOT intervene further
- Severe obstruction: cannot cough, speak, or breathe; silent attempts to cough; cyanosis → INTERVENE
- Adult/child >1 year severe obstruction: 5 back blows (between scapulae) → 5 abdominal thrusts (Heimlich). Alternate until relieved or unconscious
- Infant <1 year: 5 back blows (face down over forearm, head low) → 5 chest thrusts (2 fingers, lower sternum). NO abdominal thrusts in infants
- If unconscious: start CPR (open airway → look for visible object → do NOT blind finger sweep → compressions + ventilations)
- Complete obstruction lasting >3–4 minutes leads to hypoxic cardiac arrest — time-critical emergency
Overview
Choking is the obstruction of the airway by a foreign body (food is the most common cause in adults; small objects/toys in children). It ranges from mild (partial obstruction — patient can still cough, speak, and breathe) to severe (complete or near-complete obstruction — silent, unable to cough effectively, rapidly becomes cyanotic and loses consciousness). In adults, food (particularly meat) is the most common cause, often associated with eating while talking/laughing, alcohol intoxication, poor dentition, or neurological swallowing difficulty. In children, small objects (coins, buttons, peanuts, grapes, small toys) are common causes. Foreign body inhalation can also cause lower airway obstruction (bronchial), particularly in children under 3 years. Rapid recognition and intervention using the back blows and abdominal thrusts algorithm is life-saving.
Epidemiology
Choking causes approximately 250–300 deaths per year in the UK. It is the fourth leading cause of accidental death. Incidence is highest in children under 5 years and adults over 65 years. Risk factors in adults include: alcohol intoxication, poor dentition, eating too fast, neurological conditions affecting swallowing (stroke, Parkinson's, dementia), and sedating medications. Risk factors in children: developmental age (hand-to-mouth behaviour), small round foods (grapes, cherry tomatoes, nuts), small toy parts, coins, and balloons. The majority of fatal choking episodes occur at home. Hospital-acquired FBAO can occur in patients with impaired swallowing or reduced consciousness.
Clinical Features
Symptoms
Sudden onset during eating or playing (in children)
Mild obstruction: coughing, able to speak (even if strained), able to breathe
Severe obstruction: unable to cough, unable to speak/cry, silent attempts to breathe, clutching throat (universal choking sign)
Witnessed foreign body ingestion/inhalation
Signs
Mild: effective cough, able to vocalise, may be wheezing between coughs
Severe: ineffective/silent cough, stridor or no breath sounds, cyanosis, decreasing consciousness
Universal choking sign: hands clutching throat
Rapid loss of consciousness if complete obstruction (within 3–4 minutes)
Investigations
First-line
Clinical recognitionChoking is diagnosed CLINICALLY at the scene — there are NO investigations to perform before treatment
Second-line
CXRAfter initial management if FB suspected in lower airway (radiopaque objects, unilateral hyperinflation/collapse). Most food is radiolucent
CT neck/chestIf FB suspected but not visible on CXR and symptoms persist
Specialist
Rigid/flexible bronchoscopyDiagnostic and therapeutic for inhaled foreign bodies that have passed beyond the larynx — especially in children
LaryngoscopyDirect visualisation and removal under anaesthesia in the emergency department (Magill forceps) if FB visible at laryngeal inlet
1
Mild obstruction (effective cough)
- Encourage the person to cough — coughing is the most effective way to clear an obstruction
- Do NOT perform back blows, abdominal thrusts, or interfere — this may worsen the obstruction
- Stay with the patient. Monitor closely. Be ready to intervene if it becomes severe
2
Severe obstruction — adult and child >1 year (conscious)
- Give up to 5 back blows: stand to the side, support chest with one hand, deliver sharp blows between scapulae with heel of hand
- Check after each blow — if obstruction not relieved → 5 abdominal thrusts (Heimlich manoeuvre)
- Abdominal thrusts: stand behind patient, place fist above umbilicus, sharp inward and upward thrust
- Alternate 5 back blows and 5 abdominal thrusts until relieved or patient becomes unconscious
- If pregnant or very obese: use chest thrusts instead of abdominal thrusts
3
Severe obstruction — infant <1 year (conscious)
- 5 back blows: hold infant face down along forearm (head lower than body, support jaw). Deliver 5 sharp blows between scapulae
- 5 chest thrusts: turn infant face up. 2 fingers on lower half of sternum. 5 sharp chest thrusts (similar to CPR but sharper and slower rate)
- Alternate back blows and chest thrusts. Do NOT use abdominal thrusts in infants (risk of abdominal organ injury)
4
Unconscious patient (any age)
- Place on firm flat surface. Call 999 if not already done
- Open airway (head tilt, chin lift). Look in mouth — remove any VISIBLE foreign body with finger sweep (do NOT blind sweep)
- Attempt 2 rescue breaths. If chest does not rise, reposition head and reattempt
- If still no rise: begin CPR (30 compressions : 2 breaths). Compressions may dislodge the object
- Check mouth each time before giving breaths — look for and remove visible FB
- Continue until object clears and ventilation achieved, or advanced help arrives
5
Post-event
- All patients who received abdominal thrusts should be assessed in hospital (risk of internal injury)
- If FB in lower airway (inhaled past larynx): refer for bronchoscopy
- CXR: if any suspicion of residual foreign body or aspiration
Complications
- Hypoxic cardiac arrest: Complete obstruction >3–4 min → cardiac arrest from hypoxia
- Aspiration pneumonia/pneumonitis: If FB or gastric contents enter lower airway
- Lower airway FB: May present days later with persistent cough, wheeze, recurrent pneumonia, or unilateral air trapping
- Abdominal organ injury: Rare complication of abdominal thrusts (liver/spleen injury). Hence all patients receiving thrusts should be assessed
- Hypoxic brain injury: If prolonged obstruction before clearance
UKMLA Exam Tips
- 1Mild obstruction (can cough) = ENCOURAGE COUGHING ONLY. Do NOT interfere
- 2Severe obstruction (cannot cough/speak) = 5 back blows → 5 abdominal thrusts. Alternate until relieved or unconscious
- 3Infant <1 year: back blows + CHEST thrusts. NO abdominal thrusts (risk of organ damage)
- 4Unconscious choking patient: start CPR. Compressions may dislodge the object. Look in mouth before each ventilation attempt
- 5Do NOT perform blind finger sweeps — only remove VISIBLE objects
- 6Post-abdominal thrusts: always assess in hospital (risk of internal injury)
- 7Lower airway FB in a child: persistent unilateral wheeze, recurrent same-side pneumonia → CXR + bronchoscopy
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