Which assessment is a clinical marker of vascular volume in a patient at high risk of extracellular fluid volume deficit?

• A. Dryness of mucous membranes
• B. Skin turgor
• C. Fullness of neck veins when supine
• D. Fullness of neck veins when upright

Answer: (C)

Assessing vascular volume focuses on signs that reflect central venous pressure and the amount of fluid in the intravascular space. When a patient is lying down, the neck veins’ appearance tells you about this pressure. If the neck veins are full in the supine position, it indicates there is enough—or even excess—blood in the vascular compartment, signaling adequate intravascular volume rather than a deficit.

Dryness of mucous membranes and skin turgor are traditional signs of tissue dehydration, reflecting interstitial or intracellular fluid loss rather than how much fluid is in the central venous system. Full neck veins when upright are not typical in dehydration and can point to venous congestion or other issues, making them a less reliable marker of vascular volume status in the context of a deficit risk.