Flat neck veins

Clinical sign characterized by barely visible or non-distended jugular veins at 30-45° recumbency, typically reflecting low jugular venous pressure and reduced right atrial filling pressure.

Causes

• Physiological causes: Normal low jugular venous pressure

• Reduced intravascular volume

  • Hypovolemia

  • Dehydration

  • Blood loss

  • Excessive fluid loss (vomiting, diarrhea, diuresis)

• Hemodynamic causes

  • Hemodynamic shock

  • Reduced venous return

  • Low cardiac preload

• Excessive vasodilation