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Emergency And Acute Medicine – Pneumothorax
Pneumothorax is defined as the presence of free air within the intrapleural space. Spontaneous pneumothorax occurs due to atraumatic rupture of an alveolus, bronchiole, or subpleural bleb. Primary spontaneous pneumothorax accounts for approximately two-thirds of cases and occurs in patients without known underlying lung disease, typically young, tall, thin individuals aged 20–40 years. Risk factors include smoking, family history, Marfan syndrome, homocystinuria, and thoracic endometriosis. Secondary spontaneous pneumothorax occurs in the presence of underlying pulmonary pathology. Tension pneumothorax is a life-threatening form in which air enters the pleural space and becomes trapped through a “ball-valve” mechanism, leading to increased intrapleural pressure, decreased venous return, reduced cardiac output, mediastinal shift, ventilation–perfusion mismatch, and hypoxemia.
Secondary pneumothorax may result from airway diseases such as chronic obstructive pulmonary disease (COPD), asthma, and cystic fibrosis; infections including necrotizing bacterial pneumonia, tuberculosis, fungal pneumonia, and Pneumocystis jirovecii infection; neoplasms; interstitial lung diseases such as sarcoidosis and idiopathic pulmonary fibrosis; lymphangiomyomatosis; tuberous sclerosis; pneumoconioses; connective tissue diseases; pulmonary infarction; endometriosis; blunt or penetrating chest trauma; and iatrogenic causes such as central line placement or other vascular access procedures.
Symptoms typically correlate with the size of the pneumothorax. Patients often present with sudden-onset, sharp, pleuritic chest pain on the affected side and shortness of breath. Some may report a dull ache in delayed presentations. Cough, malaise, or minimal symptoms may occur in small pneumothoraces. On examination, patients may have tachypnea and asymmetric decreased breath sounds with hyperresonance to percussion on the affected side. Simple spontaneous pneumothoraces usually have heart rates under 120 bpm. In tension pneumothorax, findings may include hypotension, tachycardia greater than 120 bpm, diaphoresis, cyanosis, jugular venous distention, tracheal deviation away from the affected side, and cardiovascular collapse.
Imaging is central to diagnosis. However, in hemodynamically unstable patients with strong clinical suspicion of tension pneumothorax, chest decompression must not be delayed for imaging. Upright chest radiography is the standard initial test and demonstrates absence of lung markings beyond a visible visceral pleural line. Additional findings may include mediastinal shift, the deep sulcus sign (particularly in supine trauma patients), inversion of the diaphragm, or displacement of the anterior junction line. Expiratory films do not significantly increase diagnostic yield. Chest CT is highly sensitive for small pneumothoraces but is rarely necessary for routine diagnosis. Point-of-care ultrasound is increasingly used; absence of lung sliding and comet-tail artifacts, along with characteristic M-mode findings, strongly suggests pneumothorax and may be more sensitive than chest radiography in experienced hands. ECG may show nonspecific changes and is often obtained to exclude cardiac causes of chest pain.
Initial stabilization includes cardiac monitoring, pulse oximetry, 100% oxygen via nonrebreather mask, and intravenous access. Unstable patients with suspected tension pneumothorax require immediate needle thoracostomy followed by tube thoracostomy. Needle decompression is performed using a 14–18 gauge angiocatheter in the second intercostal space at the midclavicular line or the fourth or fifth intercostal space at the anterior axillary line. Standard angiocatheters may be too short in larger patients; longer catheters may be required.
Management depends on size and clinical stability. Small primary spontaneous pneumothoraces with less than 15% lung collapse and no respiratory or cardiovascular compromise may be observed with 100% oxygen for 4–6 hours, followed by repeat chest radiography. Simple aspiration using an 8F catheter with a three-way stopcock may be attempted for 15–30% collapse or enlarging small pneumothoraces. Air is aspirated until resistance is met or up to 3 liters have been removed. If imaging confirms resolution, the catheter can be removed and the patient discharged with follow-up. A second aspiration may be attempted if the first fails. A Heimlich valve may be used for persistent but stable pneumothoraces with less than 30% collapse after failed aspiration. Suction at 20 cm H₂O may be applied if necessary.
Tube thoracostomy is indicated for tension pneumothorax, traumatic pneumothorax, pneumothorax in patients requiring positive-pressure ventilation, pneumothorax with greater than 30% collapse, most secondary pneumothoraces, or definitive management after needle decompression. Small-caliber tubes (7–14F) are appropriate for primary spontaneous pneumothorax, whereas larger tubes (20–28F) are used for secondary pneumothorax or when pleural fluid or mechanical ventilation is anticipated. All side holes must remain within the thoracic cavity to prevent air leak. The tube is connected to a water-seal device or Heimlich valve in stable patients without effusion. Complications include intercostal vessel bleeding, tube kinking or clogging, malposition, and re-expansion pulmonary edema, which requires supportive care.
Local anesthesia with 1% lidocaine with epinephrine (maximum 7 mg/kg up to 500 mg) is used for procedures, and procedural sedation may be considered in stable patients. Antibiotics are not indicated for clean procedures.
Admission is required for tension pneumothorax or any patient requiring chest tube placement. Stable patients with small pneumothoraces managed conservatively or with successful aspiration may be discharged with close follow-up at 24 hours and one week, including repeat chest radiographs. Patients must receive clear instructions to return immediately for recurrent chest pain or dyspnea. Persistent failure of lung re-expansion at one week warrants cardiothoracic surgery consultation.
Timely recognition and decompression of tension pneumothorax are critical to prevent rapid hemodynamic compromise. Proper tube placement and awareness of associated injuries, including mediastinal or esophageal pathology when pneumomediastinum is present, are essential to avoid complications.
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