Airway Management

Author:

Thomas L.Knorr

Carlo L.Rosen

Description

Techniques that ensure adequate oxygenation and ventilation
Oral and nasopharyngeal airways:
- Lift tongue off hypopharynx
- Facilitate bag-valve-mask (BVM) ventilation
- Insert when gag reflex is absent
RSI:
- Preferred method for ED oral intubation (minimizes aspiration risk)
- Rapid induction of anesthesia and paralysis
- Contraindicated in patients who should not be paralyzed
- A preformulated backup strategy with alternative airway techniques is essential
- Use of fiberoptic techniques maximizes success
Oral awake intubation:
- Oral intubation with sedation only
  - Use when paralysis is contraindicated
- Ketamine is most commonly used
  - Use with benzodiazepines
Gum elastic bougie:
- Airway adjunct used when vocal cords are not well visualized
- Placement confirmed by feeling bougie bump against tracheal rings
- Slide endotracheal tube (ET) over bougie, then remove bougie
Alternative airway devices:
- Extraglottic devices:
  - Inserted blindly into oropharynx and inflated
  - Laryngeal mask airway (LMA) forms a seal around glottic structures in hypopharynx
  - LMA offers less protection against aspiration than ET tube
  - Intubating LMA can be used to place an ET tube
  - Esophageal-tracheal tubes (e.g., Combitube, King LT) occlude the esophagus and ventilate the hypopharynx
- Video laryngoscopes:
  - Fiberoptic camera on the tip of laryngoscope blade (e.g., Glidescope, C-MAC) or LMA to visualize tube placement
- Fiberoptic intubating stylets:
  - Fiberoptic camera on the tip of a stylet which holds ET tube (e.g., Shikani)
Classic fiberoptic intubation:
- ET tube placed over bronchoscope
- Nasotracheal or orotracheal approach
- Indications:
  - Anatomic limitations to glottis visualization
  - Limited mobility of mand ible or cervical spine
  - Unstable cervical spine injury
- Contraindications:
  - Need for immediate airway management
  - Significant oropharyngeal blood
Nasotracheal intubation:
- Indications:
  - Oral access impaired
  - Unsuccessful oral intubation
  - Paralysis is contraindicated
  - Limited cervical mobility
- Contraindications:
  - Apnea (only absolute contraindication)
  - Anticoagulation
  - Massive facial, nasal, or head trauma
  - Upper airway abscess
  - Epiglottitis
  - Penetrating neck trauma
Cricothyrotomy:
- Definitive treatment for a failed airway
- Incision in cricothyroid membrane
- Tracheostomy tube inserted percutaneously into the airway
- Indications:
  - Crash airway when other airway attempts fail
  - Massive facial trauma
  - Total upper airway obstruction
- Contraindications:
  - Laryngeal crush injury
  - Tracheal transection
  - Relative: Expand ing zone II or III hematoma
Noninvasive positive pressure ventilation:
- Ventilatory support without use of an invasive artificial airway
- Typically via facemask or nasal piece
- Indications:
  - Cooperative patient
  - Prehospital undifferentiated dyspnea
  - Most effective for conditions which respond quickly to treatment (COPD and CHF)
- Contraindications:
  - Intractable emesis
  - Upper airway obstruction
  - Inability to protect airway or clear secretions
  - Hemodynamic instability
  - Altered mental status or coma
  - Cardiac or respiratory arrest
High-flow nasal oxygen:
- Heated, humidified high-flow oxygen provides increased comfort vs. conventional nasal cannula
- Provides FiO₂ up to 1.0 at 60 L/min
- Provided minimal positive end expiratory pressure
- Indications:
  - Hypoxemic respiratory failure without hypercapnia
- Contraindications:
  - Epistaxis
  - Nasal obstruction
  - Basilar skull fracture
  - Recent surgery to nares or aerodigestive tract
Percutaneous translaryngeal ventilation (PTV):
- Percutaneous placement of 12G or 14G catheter through cricothyroid membrane
- Intermittent ventilation via high-pressure oxygen source
- Indications:
  - Failed oral or nasal intubation until cricothyrotomy is complete
- Contraindications:
  - Upper airway obstruction preventing expiration

Diagnosis

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[Section Outline]

Signs and Symptoms
Essential Workup
Diagnostic Tests & Interpretation
Differential Diagnosis

Signs and Symptoms

Clinical conditions requiring airway management:

Failure to maintain or protect the airway:
- Oropharyngeal swelling
- Absent gag reflex
- Inability to clear secretions, blood
- Stridor
Hypoxia or ventilatory failure:
- Shortness of breath
- Altered mental status
- Status epilepticus
Anticipated clinical course:
- Ventilatory control for head injury or tricyclic overdose
- Sedation for diagnostic or therapeutic procedures
- Early management if the airway might become compromised

Essential Workup

Always be prepared with a difficult airway algorithm prior to beginning the procedure.
Recognition of a difficult airway (LEMON):
- LOOK for anatomic considerations:
  - Short mand ible, thick neck, narrow mouth, large tongue, and protruding teeth
  - Congenital syndromes, acromegaly
  - Obesity
- EVALUATE 3-3-2 rule (difficult airway if met):
  - Mouth opens <3 fingerbreadths
  - Horizontal length of mand ible <3 fingerbreadths
  - Thyromental distance <2 fingerbreadths
- MALLAMPATI criteria (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
- OBSTRUCTION from underlying disease states:
  - Angioedema
  - Goiter
  - Laryngeal-tracheal tumors
  - History of radiation therapy to the neck
  - Infections (epiglottitis, supraglottitis, croup, intraoral or retropharyngeal abscess, Ludwig angina)
  - Profuse upper gastrointestinal hemorrhage
  - Trauma (facial, neck, cervical spine, laryngeal-tracheal, burns)
- NECK mobility limitation:
  - Rheumatoid arthritis and other arthropathies that decrease cervical spine mobility
  - Spinal immobilization for trauma
Verification of correct tube placement:
- Visualization of tube passing through the vocal cords
- Tracheal tube depth (tube tip to upper incisors):
  - 21 cm (women)
  - 23 cm (men)
  - Age (yr)/2 + 12 (children)
- End-tidal CO₂ colorimetric device:
  - Changes color if CO₂ is present, indicating tracheal placement
  - Color change may not be seen in cardiac arrest
- Auscultate over stomach, axillae, and anterior lung fields
- Observe chest wall movement
- Condensation in the tube during ventilation

Diagnostic Tests & Interpretation

Lab

Pulse oximetry should rise after tracheal intubation
- Continuous capnography used as adjunct
Arterial blood gas to manage ventilator settings after intubation

Imaging

CXR:

To exclude mainstem bronchus intubation or pneumothorax
Does not rule out esophageal intubation

Diagnostic Procedures/Surgery

Direct visualization of the ET tube through the cords is gold stand ard

Differential Diagnosis

Esophageal intubation
Right or left mainstem bronchus intubation
Extratracheal placement through tear in pyriform sinus or trachea
Pneumothorax

Treatment

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[Section Outline]

Prehospital
Initial Stabilization/Therapy
ED Treatment/Procedures
Medication

Prehospital

Options for patients in respiratory arrest for advanced life support (ALS) providers:

Bag-valve management (BVM) ventilation followed by definitive airway management in the ED
Orotracheal intubation
Esophageal-tracheal tubes
LMA

Initial Stabilization/Therapy

Maintain inline cervical spine immobilization in trauma
Oxygen, monitor, IV

ED Treatment/Procedures

RSI:
- Simultaneous administration of sedation (induction agent) and paralysis to provide optimal conditions for emergency airway management
Prepare equipment:
- Suction, BVM, various sizes of ET tubes and laryngoscope blades, stylets, medications, and backup devices
Preoxygenation:
- 100% FIO₂ for 3 min prior to induction and paralysis
- Apneic oxygenization after paralysis via nonrebreather and nasal cannula
Pretreatment:
- Prevents physiologic sequelae of intubation
- Performed 3 min prior to paralytic
- Defasciculating dose of nondepolarizing agent
- Fentanyl and lidocaine may minimize ICP rise and hemodynamic response to intubation in head-injured patients
- Lidocaine and albuterol in reactive airway disease
Paralysis with induction:
- Administration of induction agent (e.g., etomidate, thiopental, midazolam, ketamine)
- Rapidly followed by administration of paralytic agent (e.g., succinylcholine, rocuronium):
  - Succinylcholine is relatively contraindicated with anticipated difficult oral intubation, open globe injury, organophosphate poisoning, burns >3 days old, denervation syndromes, myopathies, and suspected hyperkalemia
  - Nondepolarizing agents (e.g., rocuronium) can be used as an alternative to succinylcholine
Positioning:
- Head extension, with midline cervical stabilization if trauma patient
- Cricoid pressure (Sellick maneuver) is controversial and optional
Placement of tube:
- After muscle tone is lost (45-60 s after succinylcholine)
- Use a stylet with the ET tube
- Place tube through vocal cords
- Inflate cuff
- Begin ventilation
- Confirm correct ET tube placement
Postintubation:
- Benzodiazepines, opiates, or propofol used for continued sedation
- Vecuronium may be used for continued paralysis

Pediatric Considerations
Estimation of ET tube size: 4 + age/4 Uncuffed ET tubes may be used in patients <8 yr old Straight Miller blade is preferred in patients <3 yr old Cricothyrotomy contraindicated in patients <12 yr old; PTV is preferred Use atropine as pretreatment to reduce secretions and attenuate vagal effect A defasciculating neuromuscular blocking agent not necessary for children <5 yr old

Medication

Atracurium: 0.4-0.5 mg/kg IV
Atropine: 0.02 mg/kg IV
Diazepam: 2-10 mg (peds: 0.2-0.3 mg/kg) IV
Etomidate: 0.3 mg/kg IV
Fentanyl: 3 mcg/kg IV
Ketamine: 1-2 mg/kg IV or 4-7 mg/kg IM
Lidocaine: 1.5 mg/kg IV
Midazolam: 1-5 mg IV (0.07-0.30 mg/kg for induction)
Propofol: 2-2.5 mg/kg IV
Pancuronium: 0.01 mg/kg IV (defasciculating dose); 0.1 mg/kg IV (paralyzing dose)
Rocuronium: 1 mg/kg IV
Succinylcholine: 1.5 mg/kg (peds: 2 mg/kg) IV; 2.5 mg/kg IM/SC
Thiopental: 3 mg/kg IV
Vecuronium: 0.01 mg/kg IV (defasciculating dose); 0.1 mg/kg IV (paralyzing dose)

Follow-Up

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Disposition

Admission Criteria

Almost all intubated patients should be admitted to an ICU

Discharge Criteria

Rarely, certain ED patients who have been intubated for airway protection or to facilitate diagnostic workup may be extubated in the ED after a period of observation and then discharged

Pearls and Pitfalls

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Failure to intubate and ventilate is a life-threatening condition:

Assess each patient for the possibility of difficult intubation
Prepare and familiarize yourself with all needed equipment and medications (including contraindications and side effects)
ALWAYS formulate your backup plan in the case of a crash airway or failed stand ard orotracheal intubation before beginning the procedure

Additional Reading

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BrownCA, WallsRM. Airway. In: WallsRA, HockbergerRS, Gausche-HillM, et al., eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed.Philadelphia, PA: Mosby Elsevier; 2018.
DriverBE, ReardonRF, et al. Basic airway management and decision-making. In: RobertsJR, HedgesJR, eds. Clinical Procedures in Emergency Medicine and Acute Care. 7th ed.Philadelphia, PA: Saunders Elsevier; 2019.
FrerkC, MitchellVS, McNarryAF, et al. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults . Br J Anaesth. 2015;115:827-848.

See Also (Topic, Algorithm, Electronic Media Element)

Rapid Sequence Intubation

Codes

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ICD9

96.01 Insertion of nasopharyngeal airway
96.02 Insertion of oropharyngeal airway
96.05 Other intubation of respiratory tract

ICD10

0CHY7BZ Insertion of Airway into Mouth and Throat, Via Natural or Artificial Opening

SNOMED

426153007 insertion of artificial airway (procedure)
7443007 insertion of oropharyngeal airway (procedure)
182692007 nasopharyngeal airway insertion (procedure)

section name header

Basics ⬇

Diagnosis ⬆ ⬇

Lab

Imaging

Diagnostic Procedures/Surgery

Treatment ⬆ ⬇

Pediatric Considerations

Follow-Up ⬆ ⬇

Admission Criteria

Discharge Criteria

Pearls and Pitfalls ⬆ ⬇

Additional Reading ⬆ ⬇