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

During hemorrhagic shock, systemic vascular resistance (SVR) tends to increase as a compensatory mechanism in response to reduced blood volume and perfusion pressure. When there is significant blood loss, the body activates several neurohormonal responses, including the release of catecholamines such as norepinephrine and epinephrine, along with activation of the renin-angiotensin-aldosterone system (RAAS).

These responses lead to peripheral vasoconstriction, which increases SVR in an attempt to maintain blood pressure and ensure that vital organs receive adequate blood flow. This compensatory mechanism helps to stabilize circulation in the face of decreased effective circulating volume and helps maintain perfusion to crucial organs during the early stages of shock.

The other options are less applicable; SVR does not remain unchanged or decrease significantly during hemorrhagic shock, as those would not adequately account for the body's compensatory responses to maintain hemodynamic stability. While the degree of change in SVR might vary with the severity of shock, the overall trend is an increase in response to systemic hypoperfusion.