Emergency Medicine · Trauma
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A tension pneumothorax (hypotension, tracheal deviation away from the affected side, JVD) demands immediate needle decompression at the 2nd intercostal space midclavicular line BEFORE any imaging.
Classic exam triad is decreased/absent breath sounds, hyperresonance to percussion, and decreased tactile fremitus over the affected hemithorax with sudden pleuritic chest pain.
The upright PA chest X-ray is the initial test in a stable patient, showing a thin white visceral pleural line with absent peripheral lung markings.
Bedside eFAST ultrasound shows an absent lung sliding sign and a barcode (stratosphere) sign on M-mode.
Large or symptomatic pneumothoraces require tube thoracostomy placed in the 4th or 5th intercostal space at the anterior axillary line.
An open pneumothorax (sucking chest wound) is treated with a three-sided occlusive dressing followed by definitive chest tube placement.
Small stable pneumothoraces (<3 cm from apex) are managed with 100% supplemental oxygen to accelerate nitrogen resorption.
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A 24-year-old man is brought to the ED after a stab wound to the left chest. He is anxious, diaphoretic, and severely dyspneic. Blood pressure is 78/50 mm Hg, pulse is 134/min, and respirations are 32/min. Examination reveals absent breath sounds and hyperresonance over the left hemithorax, distended neck veins, and tracheal deviation to the right.
Which of the following is the most appropriate immediate next step in management?
Immediate needle decompression at the left 2nd intercostal space, midclavicular line.
The combination of hypotension, distended neck veins, tracheal deviation, and unilateral absent breath sounds with hyperresonance is diagnostic of a tension pneumothorax. This is a clinical diagnosis requiring immediate needle decompression before obtaining a chest radiograph, as delay risks fatal obstructive shock.
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Etiology / Epidemiology
Caused by blunt or penetrating chest trauma, or iatrogenically via central line placement or thoracentesis.
Clinical Manifestations
Sudden-onset pleuritic chest pain, dyspnea, decreased breath sounds, and hyperresonance to percussion on the affected side.
Diagnosis
Upright chest radiograph shows a visceral pleural line; bedside ultrasound reveals an absent lung sliding sign.
Treatment
Small cases use 100% supplemental oxygen; larger/symptomatic require tube thoracostomy; tension pneumothorax demands immediate needle decompression.
Prognosis
Generally excellent with prompt drainage, but prolonged collapse risks re-expansion pulmonary edema upon reinflation.
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Epidemiology & Etiology
Most commonly caused by blunt chest trauma (rib fractures lacerating the lung) or penetrating trauma resulting in a classic sucking chest wound. Iatrogenic causes are highly tested, especially following subclavian vein catheterization, thoracentesis, or positive-pressure mechanical ventilation barotrauma. Failure to recognize and rapidly treat these mechanisms can rapidly progress to a fatal tension pneumothorax.
Pertinent Anatomy
The pleural space is a potential space between the visceral pleura (lung) and parietal pleura (chest wall) normally maintained at negative intrapleural pressure. Trauma violates this anatomical barrier, allowing atmospheric air to enter, which disrupts the outward pull of the chest wall against the inward recoil of the lung and risks hypoxic respiratory failure.
Pathophysiology
Disruption of the pleural membrane allows air to enter the pleural space, and the loss of negative intrapleural pressure causes the lung to collapse due to its inherent elastic recoil. In an open pneumothorax, the chest wall defect is large enough (≥2/3 tracheal diameter) that air preferentially enters the chest wall rather than the trachea. If a one-way valve tissue flap forms, air enters during inspiration but cannot escape during expiration, leading to a tension pneumothorax that mechanically compresses the superior vena cava, causing decreased venous return and obstructive shock.
Clinical Manifestations
Patients typically present with acute dyspnea, tachypnea, and pleuritic chest pain. Physical exam classically reveals decreased or absent breath sounds, hyperresonance to percussion, and decreased tactile fremitus over the affected hemithorax. A visible sucking chest wound with bubbling blood strongly indicates an open pneumothorax. The sudden development of hypotension, tracheal deviation to the contralateral side, or jugular venous distension are extreme red flags signaling a lethal tension pneumothorax.
Diagnosis
The initial test of choice in a stable patient is an upright PA chest X-ray, which reveals a thin white visceral pleural line with a lack of peripheral lung markings. Bedside eFAST ultrasound is highly sensitive in trauma, demonstrating an absent lung sliding sign and the presence of a barcode sign (or stratosphere sign) on M-mode. In severe multitrauma, a non-contrast chest CT is the gold standard for detecting occult pneumothoraces and guiding surgical intervention.
Treatment
Stable patients with a small pneumothorax (<3 cm from apex or <15-20% hemithorax) are managed with 100% supplemental oxygen to accelerate nitrogen resorption. Symptomatic or large pneumothoraces require a tube thoracostomy (chest tube) placed in the 4th or 5th intercostal space at the anterior axillary line. An open pneumothorax requires a three-way occlusive dressing (allows air out, prevents air in) followed by definitive chest tube placement. A tension pneumothorax requires immediate needle decompression in the 2nd intercostal space midclavicular line (or 5th ICS anterior axillary line) before obtaining any imaging.
Prognosis
Most traumatic pneumothoraces resolve completely with appropriate chest tube drainage and a Heimlich valve (flutter valve) for transport. A rare but severe complication is re-expansion pulmonary edema, which occurs if a chronically collapsed lung is rapidly reinflated. Persistent air leaks lasting >3-5 days may require video-assisted thoracoscopic surgery (VATS) with mechanical or chemical pleurodesis.
Differential Diagnosis
Hemothorax: Occurs in major chest trauma but presents with dullness to percussion rather than hyperresonance.
Cardiac Tamponade: Penetrating trauma causing hypotension and jugular venous distension (Beck's triad), but breath sounds remain equal bilaterally.
Pulmonary Embolism: Presents with sudden pleuritic chest pain and dyspnea without trauma, with normal breath sounds and a clear X-ray.
Rib Fracture: Presents with focal chest wall tenderness and pain on inspiration, but breath sounds are preserved.