Foreign Body Aspiration - Acute Upper Airway Obstruction and Bronchoscopy

Quick Answer

What is foreign body aspiration (FBA)?

Foreign body aspiration is the inhalation of objects into the airway, most commonly affecting children aged 1-3 years (peak incidence). It is a life-threatening emergency requiring prompt diagnosis and intervention. [1,2] Inhaled foreign bodies most commonly lodge in the right bronchus (due to wider diameter, more vertical orientation than left).

Epidemiology:

• Incidence: 10-40 per 100,000 children per year [1]
• Mortality: <1% in developed countries (higher if untreated or delayed)
• Most common objects: Peanuts (most dangerous), seeds, small toys, food items, coins (esophageal, but can compress airway)

Clinical presentation - Triad:

1. History of choking (witnessed or unwitnessed in 50%)
2. Coughing/choking (immediate, persistent)
3. Unilateral wheeze or decreased air entry

Clinical phases (historical):

1. Initial event: Choking, coughing, gagging, cyanosis
2. Asymptomatic interval: Foreign body lodged, reflex fatigue (hours to weeks)
3. Complications: Obstruction, inflammation, pneumonia, atelectasis, bronchiectasis

Emergency management of complete obstruction:

• Infant <1 year: 5 back blows + 5 chest thrusts (Heimlich not recommended)
• Child >1 year: Heimlich maneuver (abdominal thrusts)
• If unresponsive: Start CPR, check airway between compressions
• Do NOT attempt blind finger sweep (may push object deeper)

Anesthetic and surgical approach:

• Rigid bronchoscopy (gold standard): Ventilation + visualization + removal
• Flexible bronchoscopy: Diagnostic, limited therapeutic
• Shared airway: Anesthetist and surgeon working simultaneously
• Spontaneous vs. controlled ventilation: Controversy (see below)
• Topical anesthesia: To airway to reduce cough/laryngospasm

Key principle: Foreign body aspiration is a "cannot intubate, cannot ventilate" scenario until the object is removed. Coordination between anesthetist and surgeon is critical. Safety requires preparation for complete airway loss, emergency ventilation strategies, and post-obstruction care.

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Clinical Overview

Definition and Pathophysiology

Definition: Inhalation of any object into the larynx, trachea, or bronchial tree.

Why children are at risk:

• Age 1-3 years: Developmental vulnerability
• Missing molar teeth (poor chewing)
• Poor coordination of swallowing/pharyngeal reflexes
• Tendency to put objects in mouth while playing/running
• Narrow airway diameter (small obstruction = significant effect)

Location of foreign bodies:

Special objects:

Classification by Severity

1. Complete obstruction (airway/larynx):

• Life-threatening emergency
• No air movement
• Severe distress, cyanosis, loss of consciousness
• Immediate action required (Heimlich, back blows, bronchoscopy)
• Mortality high if not relieved within minutes

2. Partial obstruction (bronchus):

• Air movement preserved but compromised
• Wheezing, cough, unilateral decreased air entry
• May have "silent chest" if total bronchus obstruction
• Urgent but not immediate emergency
• Can develop complications if delayed (>24 hours)

3. Distal obstruction (segmental/bronchiole):

• Subsegmental atelectasis
• May be asymptomatic initially
• Presents later with pneumonia, abscess
• Less urgent but requires removal

Epidemiology

Risk factors:

• Neurological impairment (poor swallowing)
• Previous aspiration
• Poor dentition
• Alcohol/sedation (adults)

Pathophysiology

Immediate effects:

• Mechanical obstruction (airflow limitation)
• Ball-valve mechanism (air enters but cannot exit → hyperinflation)
• Complete obstruction → atelectasis (absorption of trapped air)

Inflammatory response:

• Foreign body reaction (especially organic material)
• Edema of bronchial mucosa
• Granulation tissue formation (days to weeks)
• Pus/mucus accumulation

Late complications:

• Pneumonia (obstruction → stasis → infection)
• Lung abscess
• Bronchiectasis
• Pneumothorax (from ball-valve mechanism)
• Empyema
• Respiratory failure

Special case - Button batteries:

• Electrochemical reaction (tissue electrolysis)
• Rapid tissue necrosis (2-hour window)
• Perforation risk
• Necrotizing esophagitis if swallowed
• If in airway: immediate removal, tissue damage

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Clinical Presentation

History

Classic triad (present in 70-80%):

1. Witnessed choking event
2. Sudden onset coughing
3. Persistent cough/wheeze since event

However:

• 50% may have unwitnessed event (found playing with small objects)
• Delayed presentation common (days to weeks)
• "Silent period" when FB lodged but asymptomatic

Symptoms by location:

Historical clues:

• "Child was eating peanuts and started choking"
• "Sudden cough while playing with small toy"
• "Persistent cough unresponsive to antibiotics"
• "Recurrent pneumonia same location"

Physical Examination

Vital signs:

• Tachypnea, respiratory distress
• Hypoxia (if significant obstruction)
• Tachycardia
• Fever (if secondary infection)

Respiratory examination:

• Stridor (inspiratory - laryngeal; biphasic - tracheal)
• Wheeze (unilateral - bronchial)
• Asymmetrical chest expansion (unilateral obstruction)
• Decreased air entry (unilateral)
• Silent chest (complete bronchial obstruction)
• Crackles (pneumonia secondary to obstruction)

"Peanut sign" on auscultation:

• Expiratory wheeze louder than inspiratory (ball-valve effect)
• Prolonged expiratory phase

Differential Diagnosis

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Investigation and Diagnosis

Imaging

Chest X-ray (PA and lateral):

Findings:

• Radio-opaque objects: Visible directly (coins, batteries, metal, some bones)
• Radiolucent objects: Not visible (most food, plastic, wood - 90% not seen on X-ray)
• Secondary signs:
  • Hyperinflation (air trapping - ball-valve)
  • Atelectasis (complete obstruction)
  • Pneumonia/consolidation
  • Mediastinal shift
  • Expiratory film shows air trapping better

Decubitus films:

• Child lies on affected side
• Normal: Dependent lung smaller (compression)
• Obstruction: No change or hyperinflation (air trapping prevents collapse)

Fluoroscopy:

• Real-time assessment of diaphragmatic paradox
• Expiratory views helpful

CT scan:

• Not first-line (radiation, delay)
• Used if diagnosis uncertain, multiple objects suspected, complications
• Virtual bronchoscopy reconstructions possible

MRI:

• Rarely used
• Can show organic foreign bodies

Bronchoscopy

Gold standard for diagnosis and treatment:

• Direct visualization
• Simultaneous removal
• Assessment of airway damage

Flexible vs. Rigid:

Combined approach:

• Flexible bronchoscopy for diagnosis
• Rigid bronchoscopy for removal
• Sometimes both needed (multiple objects, distal location)

Laboratory Tests

Preoperative (if time permits):

• CBC (infection, anemia)
• CRP (inflammation)
• Blood gas (if severe obstruction)
• Group and hold (rarely need transfusion, but prepare)

Contraindications to immediate bronchoscopy:

• Severe pneumonia/sepsis (may need antibiotics first)
• Coagulopathy (correct first)
• Extreme respiratory failure (may need stabilization, ECMO in extreme cases)

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Management

Emergency Management (Complete Obstruction)

Algorithm:

Conscious child:

1. Encourage coughing (if effective)
2. If ineffective:
   • Infant <1 year: 5 back blows (between scapulae) + 5 chest thrusts (sternum)
   • Child >1 year: Heimlich maneuver (abdominal thrusts)
3. Alternate back blows/chest thrusts or Heimlich until relieved
4. Call for help simultaneously

Unconscious child:

1. Start CPR (30:2 ratio)
2. Look in mouth before breaths (remove if visible)
3. Continue CPR until object removed or child recovers

Important:

• Do NOT perform blind finger sweeps
• Do NOT delay calling emergency services
• If object visible and easily graspable, remove with fingers

Bronchoscopy - Preoperative Preparation

Team preparation:

• Experienced anesthetist (paediatric airway)
• Experienced ENT surgeon/paediatric bronchoscopist
• Nursing staff familiar with bronchoscopy
• Resuscitation equipment ready
• Multiple sized bronchoscopes available
• Various forceps types (peanut forceps, alligator, basket)

Equipment:

• Rigid bronchoscopes (various sizes: 2.5-6.0 mm for children)
• Hopkins rod telescope
• Video system
• Oxygen source, suction
• Ventilator or T-piece system
• Emergency airway equipment (tracheostomy set)

Anesthetic machine:

• Pediatric circuits
• T-piece capability
• High-flow oxygen
• Suction

Communication:

• Discuss plan with surgeon (approach, ventilation strategy, expected difficulty)
• "Time out" before procedure
• Clear roles and backup plans

Anesthetic Management

Goals:

1. Maintain oxygenation/ventilation during procedure
2. Prevent laryngospasm/coughing during instrumentation
3. Provide motionless patient for surgical precision
4. Rapid emergence once object removed
5. Be prepared for emergency surgical airway

Controversy: Spontaneous vs. Controlled Ventilation:

Current evidence/approach:

• No clear superiority; surgeon preference often guides
• Many use spontaneous or assisted ventilation initially
• Switch to controlled ventilation once object secured or if oxygenation compromised
• Topical anesthesia critical for either approach

Anesthetic technique:

Preparation:

• Standard monitors (ECG, SpO2, NIBP, EtCO2, temperature)
• IV access (2 if possible - one for fluids/drugs, one for emergency)
• Atropine 20 mcg/kg IV (reduces secretions, prevents OCR)
• Glycopyrrolate alternative
• Antisialagogue effect important (reduces secretions obscuring view)

Induction:

• Goal: Deep anesthesia, maintain spontaneous ventilation initially
• Options:
  • Sevoflurane inhalational (maintain deep level)
  • Propofol TIVA (4-6 mg/kg/hr)
  • Ketamine (preserves airway reflexes) - controversial

Topical anesthesia:

• Critical step to reduce laryngospasm, coughing
• Lidocaine 2-4% via nebulizer or direct spray to cords
• Max dose: 4-5 mg/kg (calculate carefully)
• Apply before bronchoscope insertion

Airway management:

• No ETT - bronchoscope is the airway
• No LMA - shared airway with bronchoscope
• Face mask with 100% O2 during preparation
• Maintain depth during instrumentation

Maintenance:

• Propofol TIVA (100-200 mcg/kg/min) or
• Sevoflurane (2-3%) delivered via side port of bronchoscope
• Remifentanil 0.05-0.1 mcg/kg/min (reduces coughing, provides analgesia, rapid offset)
• Avoid N2O (reduces FiO2, diffusion hypoxia risk)
• Top-up lidocaine via bronchoscope as needed

Muscle relaxation:

• Optional - many avoid to preserve spontaneous ventilation
• If used: Rocuronium 0.3-0.6 mg/kg (shorter duration)
• Sugammadex available for rapid reversal if needed

Ventilation strategies:

1. Spontaneous ventilation:

• Patient breathes around bronchoscope
• May need assisted breaths if depth insufficient
• Watch for fatigue, rising CO2

2. Controlled ventilation through bronchoscope:

• Attach ventilator to side port
• Manual or pressure-controlled ventilation
• Watch for barotrauma (gas trapping behind object)
• Allow passive exhalation (don't force - risk of pushing object distally)

3. Apneic oxygenation (intermittent):

• Preoxygenate, remove bronchoscope for suctioning
• Reinsert for ventilation
• For brief periods only

4. Jet ventilation:

• Sanders injector or similar
• High-frequency, low-tidal volume
• Requires closed system
• Risk of barotrauma, pneumothorax

Monitoring during procedure:

• Continuous SpO2 (may be challenging due to instrumentation)
• EtCO2 (side stream from bronchoscope)
• Heart rate (bradycardia with hypoxia or OCR)
• Airway pressure (if ventilating)
• Depth of anesthesia (clinical signs, BIS optional)

Complications during bronchoscopy:

• Hypoxia: Most common; increase FiO2, suction, ventilate, remove scope if severe
• Laryngospasm: Stop stimulation, increase depth, positive pressure, consider topical lidocaine, suxamethonium if severe
• Bradycardia: Usually hypoxia; treat cause, atropine 20 mcg/kg
• Obstruction worsening: Edema, secretions, object migration; increase depth, suction, consider tracheostomy if complete
• Bleeding: Usually minor; topical adrenaline if significant
• Barotrauma: Pneumothorax if jet ventilation or over-pressurization; watch airway pressures
• Foreign body dislodgement/migration: Object falls into other bronchus or larynx; adapt approach, may need urgent removal or change position

Post-Procedure Care

Immediate:

• Recovery position (lateral, head down if secretions)
• Oxygen via face mask until awake
• Suction oropharynx before emergence
• Smooth emergence (coughing/straining risk of laryngospasm)
• Monitor for stridor, respiratory distress, re-obstruction

Post-bronchoscopy complications:

• Laryngeal edema (stridor, hoarseness)
• Subglottic stenosis (rare, from repeated instrumentation)
• Pneumonia (from pus/secretions dislodged)
• Pneumothorax (barotrauma)
• Atelectasis (if incomplete removal)

Observation:

• Usually admit for 24 hours
• Chest X-ray post-procedure (confirm removal, check for complications)
• Steroids if significant edema (dexamethasone 0.3 mg/kg)
• Nebulized adrenaline if stridor (0.5 mL/kg of 1:1000, max 5 mL)
• Antibiotics if secondary infection
• Repeat bronchoscopy if incomplete removal or complications

Discharge criteria:

• Airway patent, no stridor at rest
• SpO2 >94% on room air
• Afebrile or source controlled
• Tolerating oral intake
• Chest X-ray satisfactory
• Family education (prevention, return precautions)

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Special Situations

Button Battery Aspiration/Ingestion

EMERGENCY:

• Tissue necrosis within 2 hours
• Can cause esophageal perforation if ingested
• Can cause tracheoesophageal fistula if in airway
• Immediate removal - do not wait for fasting

Management:

• Urgent rigid esophagoscopy or bronchoscopy
• May need multiple procedures
• Post-removal surveillance for delayed perforation
• Repeat imaging/scope in 24-48 hours
• Broad-spectrum antibiotics
• Nil by mouth until mucosal integrity confirmed

Sharp Object Aspiration

Risk:

• Perforation of airway/esophagus
• Mediastinitis
• Vascular injury

Management:

• Careful removal (may need protective sheath)
• Orientation during removal critical
• Post-procedure imaging for complications

Multiple Foreign Bodies

Risk:

• Delayed diagnosis of second object
• Continued symptoms after apparent removal

Management:

• Systematic examination of all airways
• Chest X-ray post-removal to confirm complete clearance
• High index of suspicion if persistent symptoms

Long-Standing Foreign Body (Weeks to Months)

Characteristics:

• Granulation tissue
• Infection
• Difficult removal
• May need staged procedures

Management:

• Antibiotics pre-procedure if infected
• Topical/systemic steroids to reduce edema
• Patience during removal (tissue friable)
• Post-procedure surveillance for bronchiectasis

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Indigenous Health Considerations

Disparities:

• Higher incidence in some remote communities (different food practices, less access to emergency care)
• Delayed presentation more common (geographic barriers)
• Limited access to paediatric bronchoscopy in remote areas
• Transfer delays may worsen outcomes

Risk factors:

• Traditional foods (seeds, nuts)
• Young children in multi-generational households
• Less awareness of choking hazards

Management approaches:

• Prevention education in community (safe eating practices)
• Telemedicine for diagnosis support
• Retrieval services (RFDS) for urgent transfer
• Clear protocols for non-specialist centers (stabilization, transfer criteria)
• Primary care education (recognition, initial management)

Cultural considerations:

• Family often large and involved in decisions
• Traditional healing may be sought first
• Clear communication about urgency
• Support for families traveling to urban centers for care

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ANZCA Exam Focus

High-Yield Topics

Written Examination:

• Pathophysiology (ball-valve, atelectasis)
• Clinical presentation (triad, phases)
• Radiology (air trapping, atelectasis)
• Anesthetic management (spontaneous vs. controlled ventilation)
• Complications (hypoxia, laryngospasm, barotrauma)

Viva Voce:

• Management of acute airway obstruction
• Bronchoscopy anesthetic technique
• Shared airway challenges
• Emergency algorithm (complete obstruction)

Common Exam Scenarios

Scenario 1: Complete Obstruction

• 2-year-old choking on peanut, cyanotic, no air entry

Key points:

• Back blows/Heimlich maneuver
• Call emergency services
• Do NOT blind finger sweep
• If unconscious, start CPR

Scenario 2: Bronchoscopy Anesthesia

• Child with peanut in right main bronchus

Key points:

• Rigid bronchoscopy
• Topical anesthesia to airway
• Spontaneous or controlled ventilation (discuss pros/cons)
• Prepare for laryngospasm/hypoxia
• TIVA or deep volatile

Scenario 3: Button Battery

• Suspected button battery in esophagus/airway

Key points:

• Emergency - remove within 2 hours
• Tissue necrosis risk
• Urgent rigid scope
• Post-removal surveillance

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Assessment Content

SAQ: Foreign Body Aspiration (20 marks)

Question:

A 3-year-old child presents with sudden onset of coughing and wheezing after eating peanuts. Chest X-ray shows hyperinflation of the right lung with mediastinal shift to the left. The child is scheduled for urgent rigid bronchoscopy.

a) What is the likely diagnosis and pathophysiology explaining the radiological findings? (6 marks)

b) Describe the anesthetic management for rigid bronchoscopy to remove the foreign body, including your approach to ventilation and specific risks you must be prepared for. (8 marks)

c) During the procedure, the child suddenly desaturates to 70% with difficult ventilation through the bronchoscope. Outline your immediate management. (6 marks)

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Model Answer:

a) Diagnosis and pathophysiology (6 marks):

Diagnosis: Foreign body aspiration (peanut) in right main bronchus

Pathophysiology:

• Ball-valve mechanism: Foreign body acts as one-way valve
  • Inspiration: Air flows past object into lung (bronchus dilates)
  • Expiration: Bronchus narrows, object obstructs outflow
  • Result: Air trapping → hyperinflation of affected lung
• Mediastinal shift: Hyperinflated right lung pushes mediastinum to left
• Radiological findings:
  • Right lung hyperlucent (hyperinflated)
  • Decreased vascular markings on right
  • Mediastinum shifted left
  • Flattened right hemidiaphragm
  • "Air trapping" on expiratory film (no collapse of right lung)

Why right side: Right main bronchus wider, more vertical than left (less angulation from trachea)

b) Anesthetic management for rigid bronchoscopy (8 marks):

Preparation:

• Experienced team (paediatric anesthetist + ENT surgeon)
• Equipment: Multiple bronchoscope sizes, various forceps, suction, video system
• Monitors: SpO2, EtCO2 (side-stream), ECG, BP, temperature
• IV access: 2 cannulae (emergency preparedness)
• Atropine 20 mcg/kg IV (reduce secretions, prevent OCR)
• Antisialagogue effect critical

Induction:

• Deep anesthesia with maintained spontaneous ventilation initially
• Options: Sevoflurane inhalation or propofol TIVA
• Avoid: Muscle relaxants initially (preserve spontaneous ventilation)

Topical anesthesia:

• Lidocaine 2-4% to vocal cords and airway (via nebulizer or spray)
• Reduces laryngospasm and coughing during instrumentation
• Max dose 4-5 mg/kg (calculate carefully)

Airway management:

• No ETT (bronchoscope is the airway)
• Maintain with face mask until ready to insert bronchoscope
• Topical anesthesia essential before bronchoscope insertion

Maintenance options:

Common approach: Start with spontaneous/assisted, convert to controlled if oxygenation compromised or object secured

Drugs:

• Propofol TIVA (100-200 mcg/kg/min) or sevoflurane via side port
• Remifentanil 0.05-0.1 mcg/kg/min (reduces cough, rapid offset)
• Supplemental topical lidocaine via bronchoscope as needed

Risks to prepare for:

• Hypoxia (most common)
• Laryngospasm
• Bradycardia (OCR or hypoxia)
• Barotrauma/pneumothorax (if jet ventilation used)
• Foreign body migration (to other bronchus or larynx)
• Bleeding
• Complete airway obstruction

c) Management of sudden desaturation (6 marks):

Immediate actions:

Specific considerations for this scenario:

• Peanut may have fragmented or migrated
• Edema/swelling around peanut may be worsening obstruction
• May need to push object into one bronchus to ventilate other lung temporarily
• Consider flexible bronchoscopy to assess if rigid scope not ventilating
• Be prepared for emergency tracheostomy if cannot ventilate or remove object
• Call for additional senior help immediately

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References

1. Foltran F, Ballali S, Passali FM, et al. Foreign bodies in the airways: a meta-analysis of published papers. Int J Pediatr Otorhinolaryngol. 2012;76 Suppl 1:S12-S19. PMID: 22321599

2. Rimell FL, Thorp A, Stokes A, et al. Characteristics of objects that cause choking in children. JAMA. 1995;274(22):1763-1766. PMID: 7500527

3. Green SS. Preventing ventilator-induced lung injury during bronchoscopy for foreign body removal. Paediatr Anaesth. 2012;22(9):926-929. PMID: 22804931

4. Zaytoun GM, Rouadi PW, Baki DH. Endoscopic management of foreign bodies in the tracheobronchial tree: predictive factors for complications. J Thorac Cardiovasc Surg. 2000;119(4 Pt 1):672-677. PMID: 10755265

5. Ciftci AO, Bingol-Kologlu M, Senocak ME, et al. Bronchoscopy for detection of foreign body aspiration in childhood. Eur J Pediatr Surg. 2003;13(3):152-157. PMID: 12892366

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