Muscular contraction compresses the veins, causing blood to return to the heart. When an extremity is paralyzed, this muscle pump action isn't present. The compromised venous blood flow may increase the thrombosis risk at the site of venipuncture and infusion. Palpation will provide valuable information about the vein condition. Veins in a well-hydrated patient should distend easily within 3 to 5 seconds.
Dehydrated patients require a longer period.
A good palpation technique is to constantly employ the same finger to feel the vein's condition. You'll develop an increased sensitivity in that finger and that will enable you to palpate veins that may otherwise go unnoticed. With your finger, press down on the distended vein. As you release the pressure, a healthy vein will rebound easily with a resilient elasticity. Veins that are sclerosed will feel hard or cord-like.