What is one of the T's that can cause pulseless electrical activity (PEA)?

Tension pneumothorax is a critical condition that can lead to pulseless electrical activity (PEA). In a tension pneumothorax, air becomes trapped in the pleural space, creating increasing pressure that can collapse the lung on the affected side and significantly impede venous return to the heart. This increased intrathoracic pressure can compromise cardiovascular function, leading to reduced cardiac output and the inability to generate effective circulation, even when electrical activity is present on the ECG.

Tension pneumothorax can manifest quickly, and if not recognized and treated promptly through decompression (e.g., needle thoracostomy), it can rapidly become life-threatening. The mechanism by which it causes PEA primarily revolves around the impaired filling of the heart due to reduced venous return and overall obstruction of the great vessels.

In this context, while traumatic cardiac arrest can indeed lead to PEA, it is primarily due to associated conditions (like hypovolemia or massive hemorrhage) rather than a direct physiologic obstruction as seen with tension pneumothorax. Other choices, such as transfusion reactions and thyroid storm, do not directly lead to PEA in the acute setting and typically involve different pathophysiological processes.