Venepuncture is the preferred method of blood sampling for term babies and causes less pain than heel prick
INDICATIONS
- Blood sampling in a baby without indwelling arterial line, or when sampling from arterial line or capillary sampling is inappropriate
EQUIPMENT
- Cleaning solution or cleaning swab – follow local infection control policy
- Appropriately labelled blood bottles and request cards
- Non-sterile gloves
- Adhesive dressing
- 23 G blood sampling needle or needle-safe cannula
- Do not use a broken needle
- Sterile gauze/cotton wool to apply to wound post-procedure
- Sharps container
PROCEDURE
Preparation
- Wash hands and wear gloves (see Infection prevention guideline)
- Second person employs containment holding and gives sucrose
- immobilisation is crucial to baby’s safety whilst undergoing phlebotomy, and to success of procedure
- Identify suitable vein (typically back of hand or foot)
- Place paper towels under limb to avoid blood dripping onto bed linen
Insertion and sampling
- Apply hand pressure around limb to distend vein
- Clean the puncture site then do not touch again
- Place thumb on skin slightly distal to proposed puncture site
- Hold needle at 10–20° angle and puncture skin
- Advance needle toward vein. Resistance may diminish slightly as needle enters vein and blood will be seen to flow
- Collect required volume taking care to mix but not shake blood
- When sampling complete, release the pressure from around the limb, place gauze/cotton wool over insertion point and withdraw needle
- Maintain pressure on site until bleeding ceases
Complications
- Inability to obtain specimen due to:
- inappropriate choice of vein
- thrombosed vein (due to previous/repeated attempts)
- inexperienced operator
- baby shocked, cold or dehydrated causing vasoconstriction
Unsuccessful attempts
- Adhere strictly to a limit on number of attempts
- If no satisfactory sample collected after 2 attempts, seek second opinion as to whether to make a further attempt or cancel procedure
- Defer to a more experienced operator
- Venous distension:
- use warm pack to encourage vasodilation and venous filling
- Transillumination of limb can help identify suitable vein
Avoid:
- Veins close to an infection, bruising and phlebitis
- Thrombosed veins
- Oedematous limbs – danger of stasis of lymph, predisposing to complications e.g. phlebitis and cellulitis
- Areas of previous venepuncture – build-up of scar tissue can cause difficulty accessing vein and result in pain
- Sampling from potential IV infusion site or long line vein (e.g. cubital fossa or long saphenous) whenever possible
Haemolysis risk factors
- Use of <23 G needle, or too large a gauge for vessel
- Drawing blood specimens from IV or central line
- Under-filling tube – ratio of anticoagulant to blood >1:9
- Reusing tubes that have been refilled by hand with inappropriate amounts of anticoagulants
- Mixing tube too vigorously
- Failing to let alcohol/disinfectant dry
- Using too great a vacuum, e.g. using too large a tube or syringe
- Squeezing can cause haemolysis and elevate serum potassium
Completion and organisation
- Keep track of all needles used and dispose of them in sharps container
- do not re-sheath needle
- Dispose of rubbish and clean tray
- Remove gloves and wash hands
- Label all samples and investigation forms at cot side
- Arrange for transfer of samples to laboratory
- Document in patient notes
SAFETY OF PRACTITIONER
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Wear well-fitting gloves during procedure to prevent contamination from potential blood spills
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gloves will not prevent needle stick injury, but the wiping effect of glove on needle may reduce volume of blood to which hand exposed
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Discard used needles directly into sharps container – do not re-sheath
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Report any incident/accident linked to needle or sharp injury immediately, and seek assistance; start PEP as soon as possible, following protocols (>72 hr, PEP not effective)
Date updated: 2024-02-07