Barotrauma, Emergency Medicine

Basics

Description

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

Etiology

Tissue damage results when a gas-filled space does not equalize its pressure with external pressure.
Boyles law: At a constant temperature, pressure (P) is inversely related to volume (V):
- PV = K (constant) or P1V1 = P2V2
- 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

Signs and Symptoms

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

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

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

Essential Workup

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

Diagnosis Tests & Interpretation

Lab
ABG for pulmonary symptoms
Imaging

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

Differential Diagnosis

Decompression sickness
Otitis media
Otitis externa
Sinusitis

Treatment

Pre-Hospital

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.

Initial Stabilization/Therapy

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

Ed Treatment/Procedures

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

Medication

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

Disposition

Admission Criteria

PBTs
Inner ear barotrauma with round window rupture or severe vertigo

Discharge Criteria

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

Followup Recommendations

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

Pearls and Pitfalls

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.

Additional Reading

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.

Codes

ICD9

993.2 Other and unspecified effects of high altitude
993.3 Caisson disease
993.9 Unspecified effect of air pressure
993.1 Barotrauma, sinus
993.0 Barotrauma, otitic
993.8 Other specified effects of air pressure

ICD10

T70.3XXA Caisson disease [decompression sickness], initial encounter
T70.9XXA Effect of air pressure and water pressure, unspecified, initial encounter
T70.20XA Unspecified effects of high altitude, initial encounter
T70.1XXA Sinus barotrauma, initial encounter
T70.0XXA Otitic barotrauma, initial encounter
T70.29XA Other effects of high altitude, initial encounter

SNOMED

44532001 Effects of air pressure (disorder)
241978003 Barotrauma of descent (disorder)
241987007 Barotrauma of ascent (disorder)
241983006 Descent barotrauma of sinuses (disorder)
242003008 Gastrointestinal barotrauma (disorder)
49252004 Otitic barotrauma (disorder)

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