Prehospital Trauma Life Support (PHTLS) Practice Test

Which of the following characterizes the washout phase of shock?

1. Systemic acidosis

2. Localized tissue acidosis

3. Edema

4. Reduced capillary blood flow

The correct answer is: Systemic acidosis

The washout phase of shock is characterized by systemic acidosis. During shock, there is a disruption in normal perfusion and oxygen delivery to tissues, which leads to anaerobic metabolism and the accumulation of lactic acid. As the condition persists, the buildup of metabolic byproducts results in systemic acidosis, reflecting a significant shift in the body's internal environment due to inadequate oxygenation at the tissue level. The washout phase signifies a point where previously accumulated waste products from anaerobic metabolism start entering the systemic circulation, contributing to an overall imbalance in acid-base homeostasis. This phase is critical to understanding how prolonged shock can impact the body’s overall metabolic state, often leading to further complications if not managed quickly and effectively.