Upper airway occlusion

Section: Head and neck Curriculum: Curriculum, page 42

Definition

• Emergency condition of upper airway obstruction secondary to FB, trauma or oedema

Epidemiology

• M>F
• Children>adults

Pathology

• Complete obstruction above level of carina
• Partial obstruction is distal to carina or above and only partially occluded
  • Right bronchus most common - shorter, broader, less angulated from carina and more airflow into right lung

Clinical

• Symptoms
  • Aspiration hx
  • Partial vs complete obstruction
• Signs
  • Can’t talk or cough
  • Stridor
  • Wheeze
  • SOB
  • Tachypnoea
  • Resp distress

Investigations

• CXR (AP and lateral)
  • FB prevents trapped air from being expired
  • Overinflated lung, ribs flared and hemipdiaphragm depressed
  • Lung volume doesn’t change during respiration - air trapping
  • DO XRAY IN EXPIRATION
  • Emphysema, atelectasis
  • Often the FB is not radiopaque
• CT
  • If high suspicion and normal CXR
• Endoscopy
  • Laryngoscopy or bronchoscopy
    • If FB identified on imaging
    • ID and remove
    • Can be done in non life threatening situation

Management

• Principles
  • Follow CRISP algorithm
  • Need to secure AIRWAY ASAP
  • Obtain airway and ventilation
  • Remove FB to prevent complications
• CRISP - back blows/chest thrust may be needed
• Enlist help of airway team - anaesthetist/ICU EARLY
• Life threatening
  • Can’t secure A with usual measures - guedel, ETT
    • EMERGENCY CRICOTHYROIDOTOMY
    • Then do direct laryngoscopy as ⅓ of FB are supraglottic
    • So can be retrieved
• Non-life threatening
  • Early dx flexible bronchoscopy
• Retrieval
  • Via scopes
  • Instruments inserted under scope guidance
  • Include forceps and suction

Cricothyroidotomy

• Indications
  • Can’t intubate can’t ventilate
• Common situations
  • Haemorrhage
  • Emesis
  • Trismus
  • Obstructing lesions
  • FB occlusion
  • Deformities
• Contraindication
  • NO ABSOLUTE ONES
  • Relative
    • Fractured larynx
    • Laryngotracheal disruption
    • Tracheal transection with distal tracheal retraction into mediastinum
      • THEN NEED tracheotomy or stabilization of distal segment and direct intubation
    • Children
      • Narrowest part is at cricoid ring (funnel shaped AW)
      • Cricoid cartilage is main circumferential support for trachea in kids
      • As c shaped tracheal rings are pliable
      • Thus a cricothyroidotomy increases the risk of subglottic stenosis
      • Recommendation - transtracheal oxygenation via 14g needle

Anticipating difficult cricothyroidotomy - SMART

• Surgery - recent or remote
• Mass - haematoma, abscess or other
• Access of Anatomy - obesity, poor landmarks, otherwise poor access
• Radiation - or other tissue deformity/scarring
• Tumour - including intrinsic AW tumour

Anatomy

• CTM boundaries
  • Superior - thyroid cartilage
  • Inferior - cricoid cartilage
  • Lateral - cricothyroid muscle
• Cricothyroid arteries
• Branches of superior thyroid arteries
• Course along sides of CTM then anastomose in the midline
• Upper half of CTM
• So incise lower half