Prehospital Trauma Life Support (PHTLS) Practice Test

Hypotension of unknown etiology in a trauma patient should be assumed to result from what?

1. Blood loss

2. Cardiac tamponade

3. Spinal injury

4. Tension pneumothorax

The correct answer is: Blood loss

In a trauma patient presenting with hypotension of unknown etiology, it is logical to assume that the most common and critical cause is blood loss. This assumption stems from the understanding that trauma often results in significant bleeding due to injuries to blood vessels, organs, or soft tissue. Hypovolemic shock, a direct consequence of decreased blood volume, is a frequent occurrence in trauma scenarios and can lead to rapid deterioration of the patient's condition. While other etiologies such as cardiac tamponade, spinal injury, and tension pneumothorax are valid considerations in specific contexts, blood loss is the most prevalent and life-threatening concern in trauma cases. For instance, while a tension pneumothorax would typically present with additional respiratory distress or signs of mediastinal shift, and cardiac tamponade would often involve a history of blunt or penetrating trauma to the chest, the lack of clear clinical signs or context makes these less likely causes in an unknown hypotensive scenario. Thus, assessing for and addressing potential hemorrhage is critical to stabilizing the trauma patient.