American Board of Surgery Qualifying Exam (ABS QE) Practice Test

What is the preload status in hypovolemic shock?

1. High

2. Low

3. Normal

4. Variable

The correct answer is: Low

In hypovolemic shock, the primary issue stems from a significant reduction in intravascular volume due to factors such as severe dehydration, blood loss, or fluid loss from burns or trauma. The preload refers to the degree of stretch of the heart muscle fibers at the end of diastole, which is primarily dependent on the volume of blood returning to the heart. In hypovolemic shock, the intravascular volume is reduced, leading to decreased venous return and consequently a lower preload. The heart has less blood to fill its chambers before pumping, which results in reduced cardiac output and inadequate perfusion of vital organs. As a consequence, the heart's efficiency is impaired, and clinical manifestations of shock, such as hypotension and tachycardia, are often observed. Understanding that preload is low in hypovolemic shock is crucial for effective management, as fluid resuscitation becomes an immediate priority to restore volume and improve cardiac output. Identifying and addressing the underlying cause of volume loss also plays a key role in the treatment of hypovolemic shock.