- In hypovolemic shock, there is a significant loss of intravascular volume, leading to reduced venous return to the heart.
- This results in decreased central venous pressure (CVP), as less blood is returning to fill the right atrium.
- Lower CVP reflects the diminished preload and contributes to the decreased cardiac output seen in this shock type.
- In contrast, conditions like cardiogenic shock cause increased CVP due to impaired cardiac function and blood backup.

Thus, decreased CVP is a hallmark hemodynamic change in hypovolemic shock.

Reference: Harrison's Principles of Internal Medicine, 20th Edition, Volume 1, Chapter 34