Vein or artery: compress first

Question 1How do you tell a vein from an artery at the bedside?

1. aUse colour: red is always the artery
2. bChoose the deeper vessel, as arteries are always deeper
3. cApply gentle pressure: the vein collapses and the artery stays open
4. dChoose the larger vessel, as veins are always larger

Question 2Why do you not rely on colour Doppler alone?

1. aArteries never show colour
2. bColour shows flow direction relative to the probe and depends on angle and settings
3. cColour Doppler never shows venous flow
4. dColour always shows veins in red

Question 3A vein does not compress with gentle pressure. Which is a likely cause?

1. aA tourniquet on the arm
2. bHeavy probe pressure
3. cThrombus in the lumen
4. dPlenty of gel on the skin

Question 4What does spectral Doppler show in an artery?

1. aPulsatile flow
2. bFlow that stops with gentle pressure
3. cNo flow
4. dFlow that varies only with breathing