Which of the following can cause pulseless electrical activity (PEA)?

Pulseless electrical activity (PEA) occurs when there is organized electrical activity in the heart but no effective mechanical contraction, leading to a lack of pulse. Among the causes listed, tension pneumothorax is a well-known and significant cause of PEA due to its rapid alteration of intrathoracic pressure. When a tension pneumothorax occurs, air accumulates in the pleural space and creates excessive pressure that can collapse the lung on the affected side and compress the heart and great vessels. This compression results in inadequate venous return, impaired cardiac output, and ultimately leads to PEA.

For effective management in critical care, recognizing tension pneumothorax as a reversible cause of cardiac arrest is crucial. Immediate intervention, typically through needle decompression followed by chest tube placement, can restore normal thoracic pressure and allow for the restoration of effective cardiac function.

Other conditions may lead to PEA, but they do not have the same immediate mechanical impact on the heart as tension pneumothorax. For example, while severe dehydration can significantly reduce blood volume and contribute to cardiac issues, it does not exert the same direct physical compression that would acutely precipitate PEA. Similarly, a surge in body temperature can lead to metabolic demands