Pneumothorax is a principal diagnosis for emergency medical services (EMS) providers to identify, which is a potentially life-threatening condition. It is commonly associated with complaints such as chest pain, shortness of breath, and trauma. The condition spans all age groups, and EMS providers should, therefore, maintain a high index of suspicion for pneumothorax for any patient with a sudden onset of acute respiratory distress and ipsilateral chest pain.

Pneumothorax is the entry of air into the potential space between the parietal and visceral pleura. Air can enter the chest cavity from a disrpution in the lung tissue or trauma to the pleura. Lung tissue can spontaneously rupture in patients with risk factors such as tobacco use, Marfan’s syndrome, underwater diving, airplane travel, and male gender. It can also occur secondarily as a part of a chronic lung disease such as chronic obstructive pulmonary disease (COPD), interstitial lung disease, or pneumocystis pneumonia (PCP) due to the destruction of lung tissue.[1] EMS providers may also encounter several different mechanisms of injury that violate the pleura creating a pneumothorax, such as penetrating trauma to the chest or blunt trauma with a rib fracture. EMS providers may be called to the outpatient setting where medical procedures involving the chest or neck may cause an iatrogenic pneumothorax, such as central venous catheter placement, thoracentesis, and lung biopsies.

EMS providers are challenged in making the diagnosis for several reasons. They do not have access to emergency department diagnostic equipment such as chest radiographs and point of care thoracic ultrasound which may clinch the diagnosis. Many patients will have comorbid conditions that may mimic a pneumothorax including COPD/asthma, congestive heart failure (CHF), and pleural effusions, which may cause decreased breath sounds during acute exacerbations and acute dyspnea. A hemothorax will have a similar presentation as a pneumothorax, with symptoms such as dyspnea, hypoxia, decreased breath sounds, and chest pain. A key clinical finding that separates these two is that a pneumothorax will have hyper-resonance to percussion, but a hemothorax will have a hypo-resonance to percussion. Definitive treatment of both conditions may require a chest tube depending on the level of severity, but only a tension pneumothorax will require needle decompression.

Ambient noise in the field may drown out differences in lateralized breath sounds. Low light, body fluid, and other environmental factors may make otherwise obvious chest wall openings unapparent in emergencies. In the appropriate clinical setting of acute dyspnea, but equivocal breath sounds, EMS providers may percuss the thorax for unilateral hyper-resonance and asymmetric tactile fremitus in making the diagnosis.

The pleura is an impermeable membrane that surrounds the lungs and is a barrier between the lungs and the chest wall. It divides the pleura into two parts. The innermost layer, the layer directly in contact with the lung parenchyma, is called the visceral pleura. The layer between the visceral pleura and the chest wall is the parietal pleura. A pneumothorax develops when air enters the potential space between the two layers of pleura.

Patients with pneumothorax typically present with acute onset of shortness of breath and unilateral pleuritic chest pain. The most common abnormal vital sign is tachycardia, but tachypnea and hypoxia may also be present in moderate to severe cases. Unilateral decreased breath sounds are the most common physical finding, but EMS providers may notice significant dyspnea, unilateral chest rise, and jugular venous distension in the most severe cases.

A pneumothorax may develop tension if the one-way entry of air causes enough intrathoracic positive pressure to accumulate, leading to decreased cardiac output and displacement of the heart and great vessels. The clinical features of tension pneumothorax include the previously mentioned characteristics plus signs of hypotension, hypoperfusion, neck vein distension, and tracheal deviation (in the latest stage of the disease). This usually occurs when the intrathoracic pressure is greater than 15 to 20 mm Hg.