Trauma Nurse Core Course (TNCC) Practice Exam 2025 - Free Practice Questions and Study Guide

A tension pneumothorax is indeed a common cause of obstructive shock. This condition occurs when air becomes trapped in the pleural space, leading to increased pressure that collapses the lung on the affected side and can compress mediastinal structures, including the heart and major blood vessels. This compression impairs the heart's ability to fill with blood, significantly diminishing cardiac output and leading to shock. The rapid accumulation of pressure in the thoracic cavity can occur due to trauma or certain medical procedures, requiring immediate intervention to relieve the pressure and restore normal physiological function.

In contrast, the other options represent different forms of shock. Massive fluid loss typically leads to hypovolemic shock, where low circulating blood volume results in inadequate perfusion. Severe allergic reactions can cause anaphylactic shock, characterized by vasodilation and increased vascular permeability rather than obstruction. Arrhythmias can lead to cardiogenic shock when the heart's ability to pump effectively is compromised, but they do not typically cause obstruction to blood flow through thoracic structures as seen in tension pneumothorax.