What is the primary cause of hypovolemic shock due to hemorrhage?

• A. Loss of fluid within the body
• B. Decreased cardiac output due to tachycardia
• C. Air embolism
• D. Pulmonary embolism

Answer: (A)

When blood is lost from hemorrhage, the circulating intravascular volume drops. That means less blood returns to the heart (reduced preload), so the heart pumps out less blood with each beat (lower stroke volume) and overall cardiac output falls. With less blood circulating and perfusing tissues, cells don’t get enough oxygen, leading to the signs of shock. Tachycardia appears as the body’s attempt to maintain perfusion, but it can’t fully compensate if the volume loss is significant. Other problems like an air embolism or a pulmonary embolism cause shock through obstruction of flow rather than simply a lack of circulating volume, and tachycardia alone is a compensatory response, not the root cause.