Rosen & Barkin's 5-Minute Emergency Medicine Consult (94 page)

BASICS

Injury resulting from the expansion or contraction of gases in an enclosed space

• Tissue damage results when a gas-filled space does not equalize its pressure with external pressure.
  
• Boyle’s law: At a constant temperature, pressure (P) is inversely related to volume (V):
  
  • PV = K (constant) or P
    ₁
    V
    ₁
    = P
    ₂
    V
    ₂
    
  • As pressure increases/decreases, volume decreases/increases.
    
• Solid and liquid-filled spaces distribute pressure equally.
  
• Volume changes are greatest in the few feet nearest the surface.
  
• Gas-filled cavities in the body are subject to expansion/contraction:
  
  • External objects:
    
    • Air pockets in dive suit/mask expand and contract.
      
  • Paranasal sinus:
    
    • Barotrauma of descent
      
    • Pressure equalization impaired through nasal ostia resulting in negative pressure in sinus cavity
      
    • Frontal sinus most commonly affected
      
  • External ear:
    
    • Barotrauma of descent
      
    • Blockage of external auditory canal results in trapped air leading to a vacuum
      
  • Middle ear:
    
    • Barotrauma of descent
      
    • Most common type of barotraumas
      
    • Seen in 30% of inexperienced divers and 10% of experienced divers
      
    • Eustachian tube provides sole route of pressure equalization for middle ear.
      
    • Inadequate clearance via eustachian tube leads to increasingly negative pressure gradient across tympanic membrane (TM).
      
  • Inner ear:
    
    • Barotrauma of descent
      
    • Results from rapid development of pressure differential across middle and inner ear (Valsalva, Frenzel maneuvers, rapid descent)
      
    • Increased pressure in inner ear may cause round or oval window to rupture.
      
    • Frequently associated with middle ear barotrauma
      
  • Teeth:
    
    • Entrapped gas within or around tooth
      
  • GI:
    
    • Barotrauma of ascent
      
    • Swallowed air in GI tract expands as external pressure decreases.
      
  • Pulmonary:
    
    • Barotrauma of ascent
      
    • Expansion of gas trapped in lungs (closed glottis, bronchospasm) leads to distention of alveoli
      
    • Can lead to alveolar rupture
      
    • Most common is pneumomediastinum
      
    • Potential arterial gas embolism (AGE) (see “Arterial Gas Embolism”)
      
    • Divers with decreased lung compliance/increased lung volumes at increased risk (chronic obstructive pulmonary disease [COPD], asthma)
      

DIAGNOSIS

• Facial:
  
  • Occlusive dive mask: Conjunctival hemorrhage, facial edema, and swelling
    
• Extremities:
  
  • Tight-fitting dive suit: Edema and erythema of the skin at locations of air pockets
    
• Paranasal sinuses (barosinusitis):
  
  • Sinus congestion, pain, epistaxis
    
  • Pain in maxillary teeth
    
  • Cheek/lip numbness from CN V neuropraxia
    
• External ear:
  
  • May result from tight-fitting hood, earplug, or earwax occluding canal
    
  • Auditory canal mucosa becomes edematous, then hemorrhagic, and ultimately tears
    
• Middle ear (barotitis media):
  
  • Begins as clogged sensation
    
  • Increasingly painful as pressure differential increases across TM
    
  • Progresses to rupture of TM
    
  • TM appearance:
    
    • Progresses from normal appearance to edema to hemorrhage to TM rupture (Teed classification)
      
• Inner ear:
  
  • Tinnitus, hearing loss, and vertigo
    
  • Similar symptoms to inner ear decompression illness (usually less vertigo)
    
• Teeth (barodontalgia):
  
  • Severe tooth pain: Possible air trapped in fillings
    
• GI (aerogastralgia):
  
  • Excessive belching
    
  • Flatulence
    
  • Abdominal distention
    
• Pulmonary (pulmonary barotrauma [PBT], or pulmonary overpressurization syndrome):
  
  • Localized pulmonary injury
    
    • Chest pain, cough, hemoptysis
      
  • Subcutaneous emphysema
    
  • Pneumomediastinum
    
    • Chest pain, neck fullness
      
  • Pneumothorax
    
    • Chest pain (pleuritic), dyspnea
      
  • Delayed symptoms include bull neck appearance, dysphagia, changes in voice character
    

Thorough dive history and timing of symptoms in relation to dive (ascent, descent, delayed)

• HEENT for tympanic membrane trauma/rupture
  
• Chest wall/neck exam for subcutaneous emphysema
  
• Lung exam for pneumothorax
  
• Neurologic exam for imbalance/ataxia representing inner ear pathology
  

Clinical diagnosis: Meticulous physical exam (as above) and thorough history should direct any workup

ABG for pulmonary symptoms

• Sinus imaging:
  
  • CT
    
  • Plain films
    
• CXR for PBT
  
• Abdominal series (upright, decubitus) for free air from a ruptured viscus
  

• Decompression sickness
  
• Otitis media
  
• Otitis externa
  
• Sinusitis
  

TREATMENT

• For barotrauma of
  descent
  , unless air-filled cavity has ruptured, no progression of disease on return to normal atmospheric pressure is to be expected.
  
• If patient requires air evacuation, maintain air cabin pressure at 1 atm or fly below 1,000 feet to avoid aggravating barotraumas.
  

Airway, breathing, and circulation management (ABCs):

• 100% oxygen for ill-appearing patients
  
• Intubation for patients with subcutaneous emphysema of neck
  
• Immediate needle thoracostomy for evidence of tension pneumothorax
  

• Establish IV access for unstable patients.
  
• Control bleeding from ear or nose.
  
• Tube thoracostomy for large pneumothorax
  
• Decongestants for middle ear or sinus congestion
  
• Antibiotics with TM or sinus rupture
  
• Analgesics
  

• Amoxicillin: 250–500 mg (peds: 40 mg/kg/24h) PO TID
  
• Trimethoprim–sulfamethoxazole (Bactrim DS): 1 tablet double-strength (160 mg/800 mg) (peds: 40 mg/200 mg/5 mL, 5 mL/10 kg/dose) PO BID
  
• Oxymetazoline (Afrin) 0.05%: 2 or 3 drops/sprays per nostril BID for 3 days
  
• Pseudoephedrine (Sudafed): 60 mg (peds: 6–12 yr, 30 mg; 2–5 yr, 15 mg/dose) PO q4–6h
  

FOLLOW-UP

• PBTs
  
• Inner ear barotrauma with round window rupture or severe vertigo
  

• Most non-PBT
  
• ENT follow-up for severe TM or sinus pathology
  

ENT referral for ruptured TM or inner ear–related signs/symptoms

• Watch closely for development of decompression sickness in patients who present with barotraumas.
  
• Perform careful lung exam for signs of pneumothorax.
  
• Perform careful history in patients with PBT, any history of neurologic symptoms indicates AGE.
  

• Divers Alert Network [Homepage]. Available at
  www.diversalertnetwork.org
  .
  
• Klingmann C, Praetorius M, Baumann I, et al. Barotrauma and decompression illness of the inner ear: 46 cases during treatment and follow-up.
  Otol Neurotol
  . 2007;28:447–454.
  
• Levett DZ, Millar IL. Bubble trouble: A review of diving physiology and disease.
  Postgrad Med J.
  2008;84:571–578.
  
• Lynch JH, Bove AA. Diving medicine: A review of current evidence.
  J Am Board Fam Med
  . 2009;22:399–407.
  
• Tourigny PB, Hall C. Diagnosis and management of environmental thoracic emergencies.
  Emerg Med Clin North Am.
  2012;30:501–528.
  

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