Which of the following are potential causes of obstructive shock? Select All that Apply.

Obstructive shock occurs when a mechanical barrier prevents adequate filling or effective pumping of the heart, leading to reduced cardiac output and impaired tissue perfusion. Unlike distributive or cardiogenic shock, the primary issue is physical obstruction to blood flow within the thoracic cavity or great vessels. Common life-threatening causes include conditions that compress the heart or restrict pulmonary circulation. Rapid identification and intervention are critical to prevent cardiovascular collapse. Rationale: A. Tension pneumothorax is a cause of obstructive shock because air accumulates under pressure in the pleural space, compressing the lungs and mediastinal structures. This pressure shift reduces venous return to the heart, leading to decreased cardiac output. Without immediate decompression, it can rapidly progress to cardiovascular collapse. B. Massive pulmonary embolism causes obstructive shock by blocking blood flow through the pulmonary arteries. This obstruction prevents effective oxygenation and increases right ventricular afterload, leading to acute right heart failure. The resulting drop in left ventricular preload significantly reduces systemic cardiac output. C. Myocardial infarction is not classified as obstructive shock; it is a primary cause of cardiogenic shock. In MI, the problem is pump failure due to damaged myocardial tissue rather than a physical obstruction to blood flow. While both can result in low cardiac output, their underlying mechanisms differ. D. Ruptured cerebral aneurysm is not a cause of obstructive shock. It leads to intracranial hemorrhage and increased intracranial pressure, which is a neurologic emergency rather than a circulatory obstruction. It may cause neurogenic complications, but it does not mechanically impede cardiac filling or output. E. Cardiac tamponade is a classic cause of obstructive shock due to fluid accumulation in the pericardial sac. The increased pressure compresses the heart, limiting ventricular filling during diastole and reducing stroke volume. This leads to decreased cardiac output and can rapidly become life-threatening without prompt intervention such as pericardiocentesis.