Phlebotomy – Withdrawing Venous Blood for Blood Testing Purposes

Phlebotomy is the introduction of a needle into a vein to withdraw a sample of blood for haematology (to assess blood cell composition eg. Complete Blood Count CBC), biochemistry (to assess electrolytes) or bacteriology (blood cultures) reasons.

Venepuncture is a highly invasive common diagnostic advanced skill regulated by institutional or ward protocols.

Blood investigations are required for:

  • evaluating treatment progress
  • screening for specific diseases
  • ensuring that a drug is within its therapeutic level (eg. checking digoxin levels to prevent digoxin toxicity)
  • checking for the patient’s wellbeing

Venepuncture Preferred Sites:

  • Basilic Vein
  • Cephalic Vein
  • Medial-Cubital Vein

The basilic vein on the dorsum of the hand can also be accessed, whilst foot veins should be accessed only as a last resort.

AVOID:

  • amputation, mastectomy or lymphoedema sides
  • fractured limb
  • paralysis sides
  • AV graft or fistula
  • IV infusion sites
  • frequently used areas for venepuncture

DO NOT USE:

  • pulsating vessels (they are probably arteries)
  • haematoma
  • oedema
  • inflammation or infection
  • fibrous veins (rigid, cordlike veins that roll)
phlebotomy
Veins and cutaneous nerves in the antecubital fossa. Median cubital vein near the cephalic vein is the first choice for a routine venipuncture to cause nerve damage least likely. Retrieved from https://www.researchgate.net/figure/Veins-and-cutaneous-nerves-in-the-antecubital-fossa-Median-cubital-vein-near-the_fig1_316596433 on 29th May 2021
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Retrieved from https://study.com/academy/lesson/major-veins-of-the-body.html on 29th May 2021
phlebotomy
Retrieved from https://study.com/academy/lesson/major-veins-of-the-body.html on 29th May 2021
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Lumen of an artery vs lumen of a vein. Retrieved from https://www.quora.com/Why-are-the-walls-of-arteries-thicker-than-those-of-veins on 29th May 2021

Factors Influencing Venous Circulation

  • VASOCONSTRICTION – anxiety, stress, shock, cold
  • VASODILATION – warm, mechanical irritation, chemical irritation
  • BLOOD PRESSURE DROP
  • THROMBOSIS
  • LOW IV COMPONENT – dehydration, haemorrhage

Phlebotomy Procedure

Equipment Needed for Venepuncture

  • tourniquet
  • alcohol swabs
  • non-sterile gloves
  • vacutainer OR syringe & needle
  • blood sample bottles
  • sharps container
  • gauze swab
  • adhesive dressing
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Retrieved from https://www.pinterest.com/pin/619596861204054162/ on 29th May 2021

Nurse Safety Procedures:

  • hand hygiene
  • gloves
  • dispose of used items correctly
  • handle needles safely
  • dispose of needles in the sharps box

Patient Safety Procedures:

  • confirm patient identity
  • perform skill only if needed
  • cross-contamination prevention
  • disinfect skin

In the case of difficult venous access:

  • tap gently onto the vein
  • put arm in warm water to encourage vasodilation
  • lower arm below the level of the heart
  • ask for assistance
  • use advanced imaging techniques

NOTES:

When taking blood, mix sample bottle between 8-10 times after withdrawal.

Bleeding following venepuncture can take up to 10 minutes to stop, thus, tell patient to apply pressure to avoid haematoma formation.

Phlebotomy Problems:

ARTERIAL STAB:

  1. immediately remove needle
  2. apply firm pressure and elevate for more than 5 minutes until bleeding stops
  3. assess movement, sensation and circulation of affected limb
  4. consult physician

NERVE DAMAGE:

  1. immediately remove needle
  2. examine movement, sensation and circulation of affected limb
  3. consult physician

HAEMATOMA PREVENTION:

  1. insert needle at correct angle to avoid opposite vein wall perforation
  2. hold vacutainer and needle steadily whilst taking blood
  3. remove tourniquet prior to removing needle
  4. apply pressure on puncture site immediately following needle removal

Below you can find a collection of videos that can help provide a more visual approach to Phlebotomy.

Phlebotomy

Special thanks to the creators of the featured videos on this post, specifically Youtube Channels OSHVideo08 and RegisteredNurseRN.

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