Inhaled Foreign Body

Airway: Rigid bronchoscope. LMA or ETT into nasopharynx can be useful to maintain airway whilst achieving adequate depth to tolerate bronchoscope.
Access: Ideal.
Pain: Stimulating intraoperatively, minimal post.
Position: Supine. Shoulder roll for bronchscope.
Time: Highly variable.
Blood loss: Minimal.
Special: Maintain spontaneous ventilation. Consider a second anaesthetist.

The inhaled foreign body is common:

Considerations

  • Patient
    • Anxious
    • Respiratory distress
      • Stridor
      • Hypoxia
  • Parent
    • Often need to rapidly develop rapport
  • Procedure
    • Airway management in operating theatre
    • Surgeon available with rigid bronch prior to induction
  • Pathology
    • Stability
    • Location
      Affected side usually has;
      • ↓ AE
      • Wheeze
      • Hyperinflation with mediastinal shift on expiration on CXR
        Ball-valve effect.

Preparation

Consider:

  • Emergence
    If not critically unwell, then waiting for fasting is appropriate.
  • Premedication
    • Sedation
      Individualised decision; respiratory depression and aspiration are major disadvantages.
    • Secretion control
      Glycopyrrolate 5μg/kg if required. Also mitigates against bradycardia with airway stimulation.
  • Second anaesthetist

Induction

  • Priority is to maintain spontaneous ventilation
    Concern that positive pressure ventilation may push the foreign body further into the airway. The risk of this is unknown, but maintaining spontaneous ventilation is preferable to avoid it.

Both intravenous or inhalational techniques are acceptable. Considerations include:

  • Location of obstruction
    Gas induction prolonged in proximal/main bronchus obstruction secondary to shunt.
  • Presence of IV
  • Preference of anaesthetist/parent/child

Inhalational

  • Gas induction with 8% sevoflurane in oxygen or nitrous oxide
    Dependent on pre-induction saturation.
  • Wean nitrous oxide to off when depth of anaesthesia allows
  • Place IV if not sited

Intravenous

  • 0.5μg/kg fentanyl
  • Incremental boluses of propofol until loss of consciousness
    Initially 1mg/kg, then 0.5mg/kg.
  • Commence maintenance, aiming to maintain spontaneous ventilation
    Children under 3 tolerate higher doses of remifentanil and propofol than order children.
    • Propofol 15mg/kg/hr
    • Remifentanil 0.2μg/kg/min
  • Slowly titrate maintenance
    Aim for respiratory rate half of pre-induction rate.
  • When adequately deep, perform laryngoscopy and anaesthetise the cords (see below)

Hybrid

  • Perform a gas induction with sevoflurane
  • Place IV if not sited
  • Commence TIVA:
    • Propofol TCI at 1μg/ml
    • Remifentanil at 0.2μg/kg/min
      With bolus to cover dead space of line.
  • Halve sevoflurane (to 4%)
  • ↑ propofol TCI to 1.5μg/ml
  • Continue to ↑ propofol target every 30-60s until at 2.5-3μg/ml
  • Turn sevoflurane off

Intraoperative

Once induced, priorities are to:

  • Anaesthetise cords
    • Initial dose of lignocaine 4mg/kg:
      • 1/3rd of volume above cords
        May precipitate coughing, indicating depth of anaesthesia is inadequate.
      • 2/3rds of volume below cords
    • Regular maintenance of 2mg/kg lignocaine Q20-25 minutes
    • Can bolus remifentanil 0.5μg/kg if ongoing airway reactivity
  • Maintain oxygenation
    • Via rigid bronchoscopy
      Attach circuit or T-piece to 22mm connector on the bronchoscope.
      • Monitor bronchoscope screen to ensure not obstructed and that gas flow will be occurring
    • Via high-flow humidified nasal oxygen
  • Maintain spontaneous ventilation
    • Keep a hand on the chest during rigid bronchoscopy to monitor respiratory rate
    • Remember ETCO2 is unreliable or unavailable with either mechanism of oxygenation
    • Positive pressure ventilation or assisted ventilation may be required if respiratory effort becomes inadequate
  • Maintain of anaesthesia
    • Too light
      Breath holds, stridor.
    • Too deep
      Preceded by bradycardia, bradypnoea.
    • Options
      • TIVA
        Usually remifentanil rate remains constant; adjust the propofol.
      • Volatile via rigid bronchoscope

Once safely underway:

  • Give 0.25mg/kg dexamethasone
    Prevent airway swelling.
  • Consider fentanyl up to 2μg/kg
    Give slowly to prevent apnoea.

Surgical Stages

Duration can be highly variable

Key stages:

  • Insertion of rigid bronchoscope
    Highly stimulating.
  • Removal of foreign body
    May precipitate soiling of good lung from contamination distal to obstruction. Higher risk with:
    • Long-duration obstruction
    • Organic substances
      • Nuts

Emergence

  • Basic airway maneuvers usually adequate to maintain airway until emergence completed
  • Can consider LMA for convenience
  • Requirement for intubation is rare and only if airway swelling is significant

Postoperative

  • Prolonged PACU stay common
  • Post-operative stridor usually manageable with nebulised adrenaline; intubation rarely required

References

  1. Bould, M.D. ‘Essential Notes: The Anaesthetic Management of an Inhaled Foreign Body in a Child’. BJA Education 19, no. 3 (March 2019): 66–67. https://doi.org/10.1016/j.bjae.2019.01.005.
  2. Roberts, Steve, and Roger E. Thornington. ‘Paediatric Bronchoscopy’. Continuing Education in Anaesthesia Critical Care & Pain 5, no. 2 (1 April 2005): 41–44. https://doi.org/10.1093/bjaceaccp/mki015.