Upper Airway Obstruction

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Upper Airway Obstruction

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Key Points

• Upper airway obstruction (UAO) is one of the most
  serious life-threatening emergencies faced by
  critical care physicians
• Functional or anatomic
• Acute or chronic

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Key Points

• Upper airway
• Conducting airways between mouth or nares and
  primary carina
• Oral cavity, nose, pharynx, larynx, extra- and
  intrathoracic trachea
• Most UAO is related to the posterior oropharynx
  and larynx

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Causes of UAO

• Traumatic
• Facial injury (mandibular and maxillary
  fractures)
• Acute laryngeal injury
• Laryngeal stenosis
• Airway burn
• Hemorrhage
• Infections
• Ludwigs angina
• Retropharyngeal abscess
• Epiglottitis
• Laryngitis
• Diphtheria
• Acute tonsillitis (quinsy)

• Endotracheal tube trauma
• Foreign bodies
• Tumors
• Laryngeal tumors
• Laryngeal papillomas
• Intrinsic or extrinsic tumors causing tracheal
  narrowing
• Laryngospasm
• Angioedema
• Angioedema of allergic origin
• Hereditary angioedema
• Vocal cord paralysis
• UAO of obesity or pachylaryngopathy

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Clinical Features

• Exertional dyspnea occurs with an airway diameter
  of 8 mm
• Dyspnea at rest, 5 mm, coinciding with the onset
  of stridor
• Since airway resistance varies inversely with the
  fourth power of the radius at the point of airway
  compromise, small advances in the underlying
  disease are likely to dramatically worsen the
  respiratory resistive load.

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Clinical Features

• Marked respiratory distress
• Aphonia or dysphonia
• Hand-to-throat choking sign
• Cyanosis
• Inspiratory stridor or crowing
• Suprasternal and intercostal indrawing

• Facial swelling and prominence of neck veins
• Absent air movement with no air entry into the
  chest on auscultation
• Tachycardia
• Thoracoabdominal paradox
• Bradycardia, hypotension, and death

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Assessment and Diagnosis of UAO

• Separate patients with potential UAO into
• Those with marked resting or progressive symptoms
  (i.e., the true emergency cases)
• And those with a somewhat more indolent or stable
  course who have features of airway obstruction
  with forced respiratory maneuvers or exercise

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Assessment and Diagnosis of UAO

• Quick history taking and physical examinations
• Laryngoscope
• Fiberoptic or rigid bronchoscope
• Correct or bypass the acute obstruction
• Lateral soft tissue X-ray of neck, airway
  tomograms, oropharyngeal/cervical CT images
• Analysis of flow-volume loops
• Airway must be narrowed by 80 to produce
  abnormalities

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Flow-Volume Loop
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Spontaneous Breathing
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Extra- and Intrathoracic lesions
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Variable Extrathoracic Lesion
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Variable Intrathoracic Lesion
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Other Obstructive Airway Disease
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Fixed Upper Airway Obstruction
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Management Strategies

• The precise management strategy obviously depends
  on the diagnosis
• Securing and maintaining a patent airway

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Modalities

• Jaw thrust maneuver
• Pharyngeal airways
• Endotracheal intubation (either transnasally or
  orally)
• Tracheostomy
• Open bronchoscope
• Intubation over a fiberoptic bronchoscope

• Helium-oxygen mixtures
• Inhaled or systemic epinephrine, norepinephrine,
  ß-mimetics, antihistamines, steroids, and
  antibiotics
• YAG laser
• Acute dilatation
• Translaryngeal airway

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Selected Causes of UAO
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Facial Trauma

• Major cause
• Motor vehicle trauma induced mandibular and
  maxillary fractures
• Management
• Stablize and protect the cervical spine during
  airway or endotracheal tube insertion
• Where spinal stability is in doubt, intubation
  over a fiberoptic bronchoscope is favored
• Hemorrhage and mucus must be cleared
• Isolation and ligature of laceration of arteries

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Acute Laryngeal Injury

• Major causes
• Laryngeal smash on the steering wheel
• Clothesline-type injuries
• Martial arts play
• Presentations
• Dysphonia, loss of laryngeal prominence,
  subcutaneous cervical emphysema
• Management
• Urgent tracheostomy or cricothyrotomy
• Early bronchoscopy with proper stenting
• Prognosis
• Poor functional results
• Common sequelae include voice change, laryngeal
  stenosis, and predisposition to aspiration

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Laryngeal Stenosis

• Major causes
• Direct trauma
• Prolonged intubation
• Radiation
• Relapsing polychondritis
• Laryngeal surgery or laser resection
• Presentation
• Patients may not be symptomatic until the airway
  reaches a 3-mm diameter
• Typical sites
• Level of cricoid
• At the cord
• Prognosis
• Cricoid injury (subglottic stenosis) meets
  variable and unpredictable success

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Laryngeal Stenosis (Post Extubation)

• Presentation
• Gradual progression of dyspnea
• Inspiratory stridor
• Increased work of breathing
• Management
• Semireclining position
• Heliox in a 7030 mixture
• Nebulization of epinephrine
• Parenteral and inhaled steroid
• Aerosolized atropine sulfate or ipratropine
  bromide
• Many patients who develop this can be treated
  with steroids and/or epinephrine (and possibly
  with noninvasive ventilation and/or heliox) and
  do not necessarily need to be reintubated
• Steroids and/or epinephrine also could be used 24
  h prior to extubation in patients with low cuff
  leak values
• Chest 2001 120 375S-396S

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Airway Burn

• Causes
• Exposure to inhaled hot particulate or hot
  expanding steam or gas
• Presentation
• Severe swelling and inflammatory response
• From nasooral cavities to mainstem bronchi,
  especially laryngeal structure
• Management
• Fiberoptic bronchoscope confirmation
• Prophylactic intubation has become standard
  practice
• Prognosis
• If airways basement membrane is destroyed,
  granulation tissue, scarring, and stenosis may
  develop

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Hemorrhage

• Causes
• Anticoagulant (usually Coumadin)
• Hereditary coagulation therapy (usually severe
  factor VIII deficiency)
• Management
• Administration of vitamin K
• Fresh frozen plasma
• Cryoprecipitate
• Platelet
• Or specific factor concentrates

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Infection with Mixed Anaerobes of Oral or
Odontogenic origin

• Ludwigs angina
• Indurative cellulitis involving both sublingual
  and submandibular spaces
• Usually has a dental origin
• Management
• Establishment of an airway
• Antimicrobial agents against polymicrobial oral
  anaerobes
• Penicillin in high dose is usually sufficient
• Addition of metronidazole or substitution with
  clindamycin provides coverage for bacteroides
  species
• Surgical drainage may be required

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Infection with Mixed Anaerobes of Oral or
Odontogenic origin

• Lateral pharyngeal space or retropharyngeal space
  infection
• Secondary to pharyngitis, parotitis, otitis,
  mastoiditis, or suppurative lymphadenitis
• Causative organisms
• Oral anaerobes
• Staphylococcus aureus
• Streptococcus pyogenes
• Management
• CT of the neck
• Appropriate antibiotics
• Surgical drainage

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Acute Epiglottits

• Causative pathogens
• In children, Hemophilus influenzae type B
• In adults, only a minority of cases are related
  to H. influenzae
• Streptococcus pyogenes, Streptococcus pneumoniae,
  and Staphylococcus aureus may be important
• Immunocompromised H. influenzae, Pasteurella
  multocida, Candida albicans
• Virus, mycoplasma, Chlamydia spp.?

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Acute Epiglottits

• Presentations
• Rapid onset of dysphagia
• Sore throat
• Drooling
• Fever
• Shortness of breath
• Muffled voice
• Hoarseness (rare)
• Forward-leaning posture
• Diagnosis
• Laryngoscope

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Acute Epiglottits

• Management
• Prophylactic intubation
• Cefuroxime has the advantage of being active
  against Staphylococcus aureus and the other
  possible bacterial causes, except Bacteroides
  fragilis
• No role for steroid, epinephrine, or heliox

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Diphtheria

• Now rare in developed world
• Even full immunization does not guarantee
  protection, 75 effective
• Local toxin produces striking neck and
  submandibular swelling, mimicking Ludwigs angina
• Diagnosis
• Pharyngeal culture
• Myocarditis or cranial neuropathies
• Management
• Prophylactic intubation or tracheostomy
• Penicillin or erythromycin along with diphtheria
  antitoxin

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Other Infections That May Cause UAO

• Acute tonsillitis or pharyngitis due to
  Staphylococcus pyogenes with progression to
  tonsillar or peritonsillar space abscess
  formation (quinsy)
• Infectious mononucleosis
• Systemic corticosteroids produce a rapid
  resolution of swollen tonsillar tissue,
  intubation is rarely necessary

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Foreign Body

• Heimlich maneuver?
• Whenever possible, the object should be grasped
  under direct vision by fingers or forceps
• Massive aspiration requires
• Intubation
• Vigorous suctioning
• Endoscopic piecemeal removal

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Laryngeal Tumors

• Usually squamous cell type
• Usually slow-growing
• Usually presentation with hoarseness
• Diagnosis
• Direct inspection
• Biopsy

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Laryngeal Papillomas

• Causative pathogen
• DNA virus
• Presentation
• Involves from false cords to distal bronchi, most
  commonly in larynx and upper trachea
• Management
• CO2 laser resection
• Interferon injection
• Argon-dye laser ablation after hematoporphyrin
  tissue sensitization

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Laryngospasm

• May be precipitated by a variety of laryngeal
  stimuli
• Blood
• Mucus
• Water
• Temperature extremes
• Direct contact (e.g., during intubation without
  sufficient topical anesthesia)
• Visceral reflex
• Central emotional factors
• Endotracheal intubation is required in severe
  cases

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Angioneurotic Laryngeal Edema

• Allergic or nonallergic
• Hereditary or nonhereditary
• Recurrent episodes of local swelling involving
  face, larynx, and the skin of extremities

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AE of Allergic Origin

• Usual offending allergens
• Foods
• Drugs, e.g., ACEi
• Inhaled substances
• Bee stings
• Poison ivy
• Poison oak
• Management
• Avoid allergens
• Immediate administration of parenteral
  epinephrine and antihistamines
• Intubation rarely required

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Hereditary AE

• Autosomal dominant
• Deficiency of C1 esterase inhibitor
• Precipitating events often obscure
• Trivial trauma
• Emotional stress
• Upset
• Management
• Urgent intubation or tracheostomy
• Administrate intravenous C1 esterase inhibitor
• Regular use of e-aminocaproic acid or danazol,
  which stimulate C1 esterase inhibitor production

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Pachylaryngopathy, Obesity

• Most with associated sleep disordered breathing
• Pachylaryngopathy
• Marked lymphoid hyperplasia in tonsillar,
  adenoidal, and lingual regions

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Trachea

• Causes
• Trauma
• Surgery-related injury
• Tumors (both intra- and extraluminal, including
  lymphomas)
• Chondromalacia
• Foreign bodies
• Thyroid
• Vascular anomalies
• Presentation
• Onset usually gradual

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Neuromuscular Disorders

• Neuromuscular disorders involving the bulbar
  muscles
• Vocal cord paralysis
• FVL variable extrathoracic upper airway
  obstruction with or without flow oscillation

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Noncardiogenic Pulmonary Edema as A Complication
of Acute UAO

• Most common cause in adults is postanesthetic
  laryngospasm
• Risk factors
• Anatomically difficult intubation
• Nasal or laryngeal surgery
• Obesity
• Short neck
• Obstructive sleep apnea
• Relatively benign course
• Supportive care with supplement oxygen
• NIPPV

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