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why would a baby's arm turn red when a tourniqet is applied?

Discussion in 'Medical Students - MD' started by oldman, May 8, 2002.

  1. oldman

    oldman Senior Citizen
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    i was trying to draw blood from a baby and when i put on the tourniqet on the the arm, it turned bright red instead of purple. why's that?
     
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  3. 12R34Y

    10+ Year Member

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    i've been a paramedic for five years and placed enormous amounts of tourniquets on all ages and nobody typically turns purple. I would think red would be more normal than purple? many people don't change color at all.

    later
     
  4. doepug

    doepug Senior Member
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    Had you kept the tourniquet on long enough, the baby's arm would have indeed turned purple. This is a question of oxygen extraction. Remember that venous blood is still reasonably saturated (SvO2 is usually ~75%). With prolonged venous occlusion, more and more oxygen would be taken out of the blood to support local metabolism.

    Hope this helps,
    doepug
     
  5. oldman

    oldman Senior Citizen
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    i know they will turn purple. this baby's arm just kept becoming more and more red. the med tech suggested it was due to jaundice, though i thought jaundice makes the baby look more orange than red.
     
  6. trouserz

    trouserz Member
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    I know that this may hold little physiological relevance to the topic at hand, but does the fact that patients with preipheral vascular disease commonly get dependent rubor have anything at all with the topic at hand?
     

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