Subcutaneous Emphysema


Background
  1. Definition: air in chest wall
  2. Sources
  3. Etiologies
  4. If extensive, suggests injury to pharynx, larynx, or esophagus

Pathophysiology

  1. Sequence of pathophysiology
  2. Important implication
  3. Generally, relatively benign condition

Diagnostics

  1. History / symptoms
  2. Physical exam
  3. Diagnostic testing

Differential Diagnosis

  1. Pneumothorax
  2. Tracheal / bronchial disruption
  3. Esophageal disruption
  4. Pulmonary contusion
  5. Diaphragmatic hernia

Treatment

  1. ATLS
  2. Specific management

Disposition

  1. Hospitalize if
  2. Possible discharge

  Physical Exam Investigations Management
Pulmonary Contusion - Blunt trauma to chest
- Interstitial edema impairs compliance and gas exchange
- CXR: areas of opacification of lung within 6 hours of trauma - maintain adequate ventilation
- monitor with ABG, pulse oximeter and ECG
- chest physiotherapy
- positive pressure ventilation if severe
 
Ruptured Diaphragm - Blunt trauma to chest or abdomen (e.g. high lap belt in MVC) - CXR:  abnormality of diaphragm/lower lung fields/NG tube placement   
- CT scan and endoscopy - sometimes helpful for diagnosis
- laparotomy for diaphragm repair and because of associated intra-abdominal injuries
Esophageal Injury - Usually penetrating trauma (pain out of proportion to degree of injury) - CXR: mediastinal air (not always)
- Esophagram (Gastrograffin)      
- Flexible esophagoscopy
- Early repair (within 24 hrs.) improves outcome but all require repair
Aortic Tear    
 
- 90% tear at subclavian (near ligamentum arteriosum), most die at scene
- salvageable if diagnosis made rapidly
- Sudden high speed deceleration (e.g. MVC, fall, airplane crash), complaints of chest pain, dyspnea, hoarseness (frequently absent)

- Decreased femoral pulses, differential arm BP (arch tear)
- CXR, CT scan, transesophageal echo (TEE), aortography (gold standard)
- see below for CXR features
- Thoracotomy (may treat other severe injuries first)
Blunt Myocardial Injury (Rare) - Blunt trauma to chest (usually in setting of multi-system trauma and therefore difficult to diagnose)      
- Physical examination: overlying injury, i.e. fractures, chest wall contusion
- ECG: arrhythmias, ST changes
- Patients with a normal ECG and normal hemodynamics never get dysrhythmias
- O2
- Antiarrhythmic agents
- Analgesia