Pulmonary Barotrauma

Other Names

• Pulmonary Barotrauma (PBT)

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Background

• This page covers pulmonary barotrauma (PBT), a disease process occurring from divers breathing compressed air who ascend too rapidly
  • Note that this page covers PBT related to sport and recreation, and does not review iatrogenic PBT from procedures or mechanical ventilation

History

• First described by Behnke and Polak and Adams in 1932

Epidemiology

• According to DAN fatality data, 15% of barotrauma is PBT (need citation)

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Pathophysiology

• See: Dive Medicine Main
• General
  • Characterized by damage to the lung parenchyma caused by an increase in pulmonary gas volume during a decrease in ambient pressure
  • Wide range of symptoms from very mild pneumothorax or pneumomediastinum to life threatening arterial gas embolism
  • Can occur in the absence of an evident overpressure event

Etiology

• General
  • Occur when the ambient pressure decreases, allowing dissolved gas to expand
  • Can occur from ascent to the surface from depths as shallow as 4 feet after breathing compressed air
  • Risk is likely increased with underlying obstructive pulmonary disease, however most cases do not identify a predisposing factor
• May occur in the following scenarios
  • Involuntary laryngospasm on ascent (e.g. caused by loss of consciousness, panic
  • Intentional or involuntary breath-holding while ascending (even for a short period e.g., coughing)
  • Sudden increase in the volume of gas supplied by scuba equipment
  • During a fast ascent
• Tetzlaff and colleagues identified a reduced mid-expiratory flow at 25% of vital capacity in divers who presented with lung barotrauma
  • Findings suggest pulmonary function testing could be used to perform risk assessment

Associated Conditions

• Pneumothorax
  • Occurs when gas in the lung interstitial space enters pleural space
  • 3% of patients in one case study of 31 patients
  • Can be simple or tension
• Pneumoperitoneum
  • 3% of patients in one case study of 31 patients
• Subcutaneous Emphysema
  • 10% of patients in one case study of 31 patients
• Pneumomediastinum
  • 25% of patients in one case study of 31 patients
• Pneumopericardium
  • 6% of patients in one case study of 31 patients
• Air Gas Emboli
  • Can result in stroke, cardiac arrest and death

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Risk Factors

• Diver related
  • Novice or inexperienced divers, likely related to breath holding
• Pulmonary
  • Obstructive disease such as asthma, bronchitis, URI, TB, tumor, emphysema
  • Tobacco Use Disorder

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Differential Diagnosis

Differential Diagnosis Dive Medicine

• Barotrauma of descent
  • Otic Barotrauma: "ear squeeze"
  • Sinus Barotrauma: "sinus squeeze"
  • Mask Squeeze: air in the mask decreases in volume during a dive, creating negative pressure
  • Barodentalgia: trapped dental air causing squeeze
• At depth injuries
  • Oxygen Toxicity: harmful effects of breathing oxygen at higher partial pressures than normal
  • Nitrogen Narcosis: toxic effects of breathing nitrogen-containing gases while at depth
  • Hypothermia: decrease core temperature with prolonged exposure to cold water
  • Carbon Monoxide Toxicity: CO toxicity typically results from a faulty air compressor
  • Caustic Cocktail: Inhalation of absorbent material used to scrub CO2 mixes with water
• Barotrauma of ascent
  • Pulmonary Barotrauma: occurs when diver breathing compressed air ascends too rapidly
  • Decompression Sickness: Dissolved nitrogen comes out of solution, forms bubbles in blood and tissue ("the bends")
  • Arterial Gas Embolism
  • Alternobaric vertigo
  • Facial baroparesis (Bells Palsy)
• Other
  • Immersion Pulmonary Edema: also termed swimming induced pulmonary edema
  • Salt water aspiration
  • Submersion Injury: includes drowning, near drowning

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Clinical Features

• History
  • Symptoms ten to occur immediately upon surfacing or within 10 minutes
  • Substernal pain exacerbated by coughing or swallowing suggests mediastinal emphysema
  • Throat pain, horseness, dysphagia, choking sensation
  • Cough, shortness of breath, hemoptysis, dypsnea, cyanosis
• Physical Exam
  • Must perform thorough cardiopulmonary and neurological exam
  • Crunching sound on auscultation may be indicative of mediastinal air (Hamman's sign)
  • Swelling or crepitus due to subcutaneous emphysema
  • Asymmetric breath sounds if large or tension pneumothorax
  • More rarely, patients have neuro-dysfunction, cardiorespiratory distress or cardiac arrest
• Special Tests

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Evaluation

Radiograph

• Standard Chest Radiograph
  • Helps include/ exclude things like pneuothorax, pneumomediastinum, etc
• Findings
  • Pneumomediastinum is most commonly seen (need citation)
  • Pneumothorax
  • Subcutaneous Emphysema
  • Pulmonary edema or infiltrates

CT

• Indications
  • No hard indications
  • Recommend angiography if any concern for AGE (Chest vs Head and Neck)
• Potential findings
  • Arterial Gas embolism
• Tetzlaff found 13 lung abnormalities among patients with pulmonary barotrauma
  • Suggests unexplained lung barotrauma may stem from occult lung disease

Ultrasound

• Echocardiogram
  • Can be used to detect number, size of bubbles in the right side of the heart

EKG

• Should be obtained on all patients
• Potential findings
  • Sinus tachycardia
  • Arrhythmia
  • Myocardial Infarction

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Classification

• Currently, no classification system exists

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Management

Nonoperative

• General
  • The patient should be transferred to the nearest Emergency Department
  • It is important that the diving team communicate with the ED staff
  • The patient should be treated with BLS and ACLS as needed
  • Obtain IV access, apply supplemental oxygen, patient may require advanced airway
• Oxygen Therapy
  • 100% Non rebreather for mild cases is likely appropriate, however mild cases will often resolve spontaneously
  • Indicated for anyone who is hypoxic
• Tension Pneumothorax
  • Requires Needle Decompression in the field if identified early
  • Definitive treatment will require Tube Thoracostomy in the hospital setting
• Hyperbaric Oxygen Therapy (HBOT)
  • Indicated for any limb or life threatening presentation, includes spinal cord injury, neurological impairment, myocardial infarction
  • Patient must be stable enough for hyperbaric chamber
  • Definitive treatment should be initiated within 2 hours if possible
  • Delays greater than 6 hours associated with worse outcomes (need citation)
• Unknown benefit
  • Heliox (50% helium/ 50% oxygen mixture)
  • Surfactant
• Restricted air travel
  • Previously recommended to wait 6 weeks until complete resolution of pneumthorax
  • Current guidelines based on sparse data recommend waiting 1-3 weeks after resolution

Prevention

• See: Prevening Diving Injuries

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Rehab and Return to Play

Rehabilitation

• Needs to be updated

Return to Play/ Work

• All divers with lung disease should be screened

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Complications and Prognosis

Prognosis

• General
  • Varies wildly based on severity
  • Mild cases have few sequalae and complete resolution
  • Air gas embolism has a 30% mortality rate (need citation)

Complications

• Air Gas Emboli
  • 30% mortality rate (need citation)
  • Can result in stroke, cardiac arrest, death
• Cerebral Embolization
  • Can result in loss of consciousness
  • Neuro dysfunction including hemiplegia, stupor, confusion, visual disturbance, seizures, vertigo, headache
  • Occurs within minutes of surfacing
• Myocardial Infarction
• Cardiac Arrest
  • Occurs in about 5% of victims
  • Due to cardiac chambers and great vessels filling with air
• Other pulmonary complicates documented in case reports
  • Aspiration pneumonitis
  • Pneumonia
  • Pleural Effusion
  • Empyema
  • Pyopneumothorax
  • Scarring and fibrosis
  • Decreased lung function

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See Also

• Dive Medicine Main
• Environmental Main
• Pulmonary Main

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