Tension Pneumothorax

A 32 year old man is brought to the emergency department after a motor vehicle collision. He has severe dyspnea and chest pain. He appears distressed and tachypneic. Vital signs show hypotension and tachycardia. On examination, breath sounds are markedly decreased on the right side and percussion is hyperresonant. The trachea is deviated to the left and jugular venous distension is present. Diagnosis?

Diagnosis is tension pneumothorax.

1. Definition

Tension pneumothorax is a life-threatening condition caused by progressive accumulation of air under pressure within the pleural space due to a one-way valve mechanism, resulting in lung collapse, mediastinal shift, impaired venous return, and obstructive shock.

2. Etiology

Traumatic Causes

1. Blunt thoracic trauma
2. Penetrating chest injury
3. Rib fractures
4. Pulmonary decompression sickness

Iatrogenic Causes

1. Central venous catheter placement
2. Thoracentesis
3. Mechanical ventilation and barotrauma
4. Percutaneous tracheostomy
5. Lung biopsy
6. Bronchoscopy
7. Pacemaker insertion
8. Cardiopulmonary resuscitation
9. Intercostal nerve block

Other Causes

1. Primary spontaneous pneumothorax
2. Secondary spontaneous pneumothorax due to underlying lung disease

3. Pathophysiology

1. Air enters pleural space through a one-way valve mechanism
2. Progressive increase in pleural pressure occurs
3. Compression and collapse of ipsilateral lung
4. Mediastinal shift toward opposite side
5. Compression of superior vena cava reduces venous return
6. Reduced preload decreases cardiac output
7. Severe cases progress to obstructive shock and cardiac arrest

4. Clinical Features

4.1 Core Features

1. Sudden severe dyspnea
2. Tachypnea
3. Tachycardia
4. Hypotension
5. Pleuritic chest pain

4.2 Examination Findings

1. Markedly decreased or absent breath sounds on affected side
2. Hyperresonance to percussion
3. Reduced tactile fremitus
4. Tracheal deviation away from affected side (late finding)
5. Jugular venous distension
6. Chest retractions
7. Cyanosis
8. Subcutaneous emphysema may occur

Clinical pearls:

• JVD may be absent in hypovolemic trauma patients
• Unilateral absent breath sounds with respiratory distress and hypotension are often more reliable than percussion findings

5. Diagnosis

Tension pneumothorax is a clinical diagnosis in an unstable patient

Do NOT delay decompression for imaging

5.1 Imaging (Only if Stable or Diagnosis Uncertain)

Bedside Lung Ultrasound

1. Absence of lung sliding
2. Presence of lung point
3. High diagnostic performance in experienced operators

Ultrasound may support diagnosis in unstable patients but should not delay treatment

Chest X-ray

1. Visible pleural line
2. Absent peripheral lung markings
3. Collapsed ipsilateral lung
4. Mediastinal shift away from affected side
5. Flattened ipsilateral hemidiaphragm
6. Possible subcutaneous emphysema

CT Chest

1. Most definitive imaging modality
2. Not routinely used in tension pneumothorax
3. Reserved for stable or unclear cases

6. Management

6.1 Immediate Management (Life-Saving)

Needle Decompression

If patient is unstable and clinical suspicion is high:

Preferred site (higher success rate):

• 5th intercostal space at the anterior axillary line

Alternative site:

• 2nd intercostal space at the midclavicular line

Use a sufficiently long angiocatheter to overcome chest wall thickness

Perform immediately without waiting for imaging

6.2 Definitive Management

Tube Thoracostomy (Chest Tube)

1. Perform after decompression
2. Insert within the triangle of safety
3. Most cases resolve with chest tube placement

6.3 Supportive Care

1. Airway stabilization
2. Breathing support
3. Circulation management (ABC approach)
4. Administer 100% oxygen
5. Hemodynamic stabilization
6. Avoid positive pressure ventilation until decompression when feasible

7. Complications

1. Obstructive shock
2. Cardiac arrest
3. Respiratory failure
4. Re-expansion pulmonary edema
5. Hemothorax
6. Bronchopleural fistula
7. Chest tube complications including infection or neurovascular injury

8. Key Clinical Insight

Acute dyspnea with hypotension, unilateral absent breath sounds, and obstructive physiology should be treated as tension pneumothorax immediately

9. Exam-Level Pearls

1. Tension pneumothorax is a clinical diagnosis
2. Needle decompression precedes imaging
3. Definitive treatment is chest tube placement
4. Tracheal deviation is a late sign
5. Positive pressure ventilation increases risk
6. Ultrasound may assist but should not delay treatment
7. Obstructive shock physiology explains hypotension and JVD
8. Most common mistake is waiting for imaging before decompression