Airway Adjuncts

Basics

Description

  • Airway adjuncts are devices used for management of the upper airway
  • Often used as rescue techniques/devices when unable to intubate with standard techniques and difficult to mask ventilate
  • Oropharyngeal airway (OGA):
    • Temporary airway adjunct in deeply unresponsive patients
    • Lifts tongue from obstructing the airway
    • Aids in bag-mask ventilation
    • Placement requires absent gag reflex
  • Nasopharyngeal airway (NPA):
    • Inserted through the nostril and extends past the base of the tongue, preventing it from collapsing against the posterior pharyngeal wall
    • Used when gag reflex intact
    • Maintains airway patency in patients with clenched jaws or semiconscious state
    • Contraindicated if basal skull fractures, significant nasal trauma
  • Classic supraglottic airways (SGAs):
    • Indications:
      • Failed or difficult endotracheal intubation
      • Difficult bag-mask ventilation
      • Useful in prehospital or emergency settings where rapid airway control is needed
      • Patients with limited neck mobility
      • Obesity or anatomic airway challenges
      • Short-term airway support
      • Bridge to definitive
  • A wide variety of SGAs are available, offering different advantages:
    • Laryngeal mask airways (LMAs) – Provide SGA support with varying features for seal, intubation, and aspiration reduction.
    • Standard LMAs – Basic airway management without gastric drainage or advanced sealing mechanisms.
    • Intubating LMAs – Designed to facilitate passage of an endotracheal tube (eg, LMA-Fastrach, Air-Q).
    • Second-generation LMAs – Include gastric drainage to reduce aspiration risk (eg, LMA-ProSeal, LMA-Supreme).
    • Noninflatable LMAs – Use gel or self-sealing mechanisms to conform to anatomy (eg, i-gel, Baska Mask).
    • Laryngeal tubes – Dual-cuff designs sealing the esophagus and oropharynx (eg, King LT, Combitube).
  • Bougie (Tracheal tube introducer)
  • Video laryngoscope (VL)
  • Fiberoptic bronchoscopy
  • Needle cricothyrotomy
  • Surgical cricothyrotomy
  • Retroglottic (RGD)
  • Infraglottic (IGD) class:
    • Combitube
    • King tube
    • Ruch EasyTube
  • RGD/IGD ventilate at the hypopharynx and occlude the esophagus

Epidemiology

  • 95% success with first method of airway management
  • 98% overall success of intubation
  • 4% of ED airways are difficult

Etiology

  • Difficulties result from various anatomic variations and pathologic conditions requiring proper selection of technique and adjuncts to ensure optimal airway management
  • Reduced visualization or distorted airway anatomy:
    • Morbid obesity
    • Micrognathia (Smail jaw)
    • Macroglossia (Large tongue
    • Neck mobility issues
    • Cleft palate
    • Pierre Robin sequence
  • Upper airway obstruction:
    • Epiglottitis
    • Laryngeal obstruction
    • Laryngospasm
    • Tracheitis or tracheobronchitis
    • Angioedema
    • Foreign body
    • Blunt and penetrating neck trauma
    • Laryngotracheal malignancy
    • Radiation therapy
  • Reduced visualization from hemorrhage:
    • Massive GI bleeding
    • Hemoptysis
    • Facial trauma
  • Physiologic difficult airway:
    • Risk of worsening underlying condition through cardiovascular collapse or periods of apnea during airway management
    • Shock
    • Severe hypoxemia
    • Acidosis

Diagnosis

Signs And Symptoms

History

  • Past surgeries, difficult intubations, and anesthesia-related complications
  • Inquire about familial issues with anesthesia, such as difficult intubation or malignant hyperthermia
  • Assess for airway-related conditions like sleep apnea, asthma, COPD, tumors, or recent infections
  • Check for dentures
  • Identify drug or latex allergies and review all current medications

Physical Exam

  • Predictors of difficult to bag-mask ventilate (MOANS):
    • M – Mask seal (beards/structural abnormality)
    • O – Obese or obstructed
    • A – Advanced age (>55 yr)
    • N – No teeth
    • S – Stiff
  • Predictors of difficult laryngoscopy and intubation (LEMON)
    • L – Look externally:
      • Micrognathia
      • Buck teeth
      • Large tongue
      • Short neck
    • E – Evaluate 3-3-2:
      • Mouth opens <3 fingerbreadths
      • Horizontal length of mandible <3 fingerbreadths
      • Thyromental distance <2 fingerbreadths
    • M – Mallampati score (increasing difficulty):
      • Class I: Soft palate, uvula, fauces, pillars visible
      • Class II: Soft palate, uvula, fauces visible
      • Class III: Soft palate visible
      • Class IV: Hard palate only visible
    • O – Obstruction:
      • Vocal changes/muffled voice
      • Difficulty managing secretions
      • Stridor
    • N – Neck mobility (limited)
  • Predictors of difficult cricothyrotomy (SHORT):
    • S – Surgery or disrupted airway
    • H – Hematoma or infection
    • O – Obese (access problem)
    • R – Radiation
    • T – Tumor
  • Predictors of difficult EGD (RODS):
    • R – Restricted mouth opening
    • O – Obstruction
    • D – Disrupted or distorted airway anatomy
    • S – Stiff lungs or cervical spine

Essential Workup

  • Select appropriate airway adjuncts based on the assessment:
    • Bougie for poor glottic visualization, SGAs for failed BMV or intubation
    • Fiberoptic intubation for complex anatomy
  • Prepare for cricothyrotomy in cases of severe upper airway obstruction, trauma, or failed airway scenarios
  • Confirming correct placement:
    • Fiberoptic bronchoscopy (gold standard)
    • End tidal capnometry/capnography (>99% reliable)
    • Physical exam (common but unreliable)
    • Chest rise/fall
    • Auscultation of breath sounds with absence of sound over epigastrium
    • Condensation inside the ETT

Diagnostic Tests And Interpretation

Lab

  • Arterial blood gas is used to guide ventilator settings once airway established

Imaging

  • CXR: Useful only in patients following endotracheal intubation to exclude mainstem bronchus intubation or pneumothorax and to adjust the position of the tube

Differential Diagnosis

Treatment

Prehospital

  • Place all patients on supplemental oxygen, pulse oximetry, end-tidal CO2, and cardiac monitor
  • Initiate therapy for suspected cause of dyspnea when indicated:
    • Asthma
    • COPD
    • CHF
  • Avoid oxygen narcosis in CO2 retainers; target SpO2 88–92%.
  • Utilize advanced airways in the face of impending/realized respiratory failure
  • Noninvasive positive pressure ventilation can rapidly improve many respiratory conditions

Initial Stabilization/Therapy

  • ABCs
  • Immediate intubation for impending respiratory arrest:
    • Altered mental status
    • Unstable vital signs
  • Noninvasive positive pressure ventilation in alert patients:
    • Contraindications:
      • Cardiac instability
      • Suspicion of upper airway obstruction
      • Decreased mental status
      • Upper GI bleeding

Ed Treatment/Procedures

  • Rapid sequence intubation
  • Prepare:
    • Suction, BVM, ETT, primary airway management modality, rescue airway management modality, medications
  • Preoxygenate:
    • Non-rebreather mask (NRB) or BVM with 100% FiO2 for 3 min
    • Consider noninvasive positive pressure ventilation for preoxygenation
  • Pretreatment:
    • Minimize adverse responses to airway management
    • Suspected elevated ICP
    • Ischemic heart disease or major vessel dissection/rupture
    • Adults with significant reactive airways disease
    • Children up to 10 yr of age
  • Paralysis with induction:
    • Administration of induction agent
    • Rapid sequential administration of paralytic agent
ALERT

Paralysis is relatively contraindicated in anticipated difficult airway:

  • Positioning:
    • Head extension
    • Cricoid pressure (Sellick maneuver)
  • Placement of tube
  • Postintubation:
    • Confirm ETT placement
    • Sedation with benzodiazepines, opiates, propofol, or other agents
    • Continued paralysis as needed combined with adequate sedation
  • Failed intubation:
    • Consider other intubation techniques in failed airway algorithm or use of airway adjunct
    • Surgical airway as last resort

Medication

  • Induction:
    • Etomidate: 0.3 mg/kg IV
    • Ketamine: 1–2 mg/kg IV or 4–7 mg/kg IM
    • Midazolam: 0.07–0.3 mg/kg IV
    • Propofol: 2–2.5 mg/kg IV
    • Thiopental: 3 mg/kg IV
  • Paralysis:
    • Succinylcholine: 1–1.5 mg/kg (peds: 2 mg/kg) IV, 2.5 mg/kg IM/SC
    • Rocuronium: 1 mg/kg IV (paralyzing dose); 0.1 mg/kg IV (defasciculating dose)
    • Pancuronium: 0.1 mg/kg IV (paralyzing dose); 0.01 mg/kg IV (defasciculating dose)
    • Vecuronium: 0.1 mg/kg IV (paralyzing dose); 0.01 mg/kg IV (defasciculating dose)
  • Reversal:
    • Sugammadex: 16 mg/kg IV for immediate reversal of rocuronium (peds: 2 mg/kg IV)
      • Limited data available for pediatric dosing, especially infants <2 y/o
    • Flumazenil: 0.2 mg IV q1min up to 1 mg for reversal of benzodiazepine (peds: 0.01 mg/kg IV q1min max of 0.05 mg/kg)

Follow-Up

Disposition

Admission Criteria

  • Almost all intubated patients should be admitted to an ICU or OR

Discharge Criteria

  • Rarely, ED patients who have been intubated may be extubated in the ED and discharged after a period of observation

Pearls And Pitfalls

  • Failure to ventilate is a life-threatening condition
  • Assess every patient for the possibility of difficult mask ventilation or intubation
  • Always formulate a backup plan in case of a failed attempt
  • Do not fixate on intubation, but rather successful ventilation and oxygenation
  • Move to alternate airway management techniques and consider surgical airway if unable to intubate or ventilate despite use of airway adjuncts

Pediatric Considerations

  • OGAs and NPAs are available in infant+ sizes
  • LMAs are available in infant+ sizes
  • Combitube is only designed for patients >48 in in height
  • Nasotracheal intubation is contraindicated in children under 10 yr of age

Additional Readings

  1. Brown CA, Sakles JC, Mick N, Mosier JM, Braude DA, eds. The Walls Manual of Emergency Airway Management. 6th ed. Lippincott Williams & Wilkins; 2023.
  2. Gibbs KW, Semler MW, Driver BE, et al. Noninvasive ventilation for preoxygenation during emergency intubation. N Engl J Med. 2024;390(20):2165–2177.  [PMID:38869091]
  3. Nordquist EK. Airway management. In: Wolfson AB, Cloutier RL, Hendey G, Ling LJ, Rosen CL, Schaider JJ, eds. Harwood-Nuss’ Clinical Practice of Emergency Medicine. 7th ed. Lippincott Williams & Wilkins; 2021.
  4. Tran DTT, Newton EK, Mount VAH, et al. Rocuronium vs. succinylcholine for rapid sequence intubation: a Cochrane systematic review. Anaesthesia. 2017;72(6):765–777.  [PMID:28654173]

See Also (Topic, Algorithm, Electronic Media Element)

Respiratory Distress

Authors

David W. Schoenfeld