Tension pneumothorax
Formal Definition
A medical emergency in which air enters the pleural space but cannot escape due to a one-way valve mechanism, causing progressive accumulation under pressure; results in complete collapse of the ipsilateral lung, shift of the mediastinum to the contralateral side, compression of the contralateral lung and great vessels, and cardiovascular collapse from impaired venous return; requires immediate needle decompression before any imaging.
How It's Used on the Ward
Tension pneumo or tensioning — a collapsed lung under pressure that is squishing the heart and big vessels; you decompress it before you CT it.
Example
"Trauma patient intubated, sudden hypotension 75/40, tachycardia 145, Trachea deviated to the right, absent breath sounds on the left, JVD present, cyanosis. Diagnosis: tension pneumothorax. Do not wait for CXR. Needle decompression left chest at 2nd ICS midclavicular line. Chest tube to follow immediately. Reassess vitals."
Clinical Context
Clinical diagnosis: not a radiological diagnosis. Signs: hypotension + tachycardia + absent unilateral breath sounds + tracheal deviation + JVD. In intubated patients: increased peak airway pressures, desaturation, hemodynamic instability. Treatment: immediate needle decompression (14-16 gauge, 2nd ICS midclavicular line on affected side, 4.5cm needle), followed by chest tube (4th-5th ICS anterior axillary line). Chest tube size: 36-40 Fr for trauma. Finger thoracostomy: newer approach using a 3-4cm incision in 4th-5th ICS anterior axillary line, allows rapid decompression before chest tube placement. In emergency, do not delay for ultrasound confirmation — clinical picture is sufficient.