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Circulation - Venepuncture

Indications

Venous blood sampling

Contraindications (absolute in bold)

Ipsilateral fistula

Ipsilateral radical mastectomy

Overlying infection

Phlebitis or thrombosis

Burns

Sclerosis

Alternatives

Blood test not required

Arterial sampling

Informed consent

Verbal consent

Less complex non-emergency procedure with low risk of complications

Potential complications

Pain

Vasovagal reaction on insertion (syncope)

Failure (to obtain sample, haemolysis, incorrect filling of vacutainers)

Vessel injury (haematoma, haemorrhage, thrombophlebitis)

Nerve injury

Thrombosis

Infection

Procedural hygiene

Standard precautions

Aseptic non-touch technique

PPE: non-sterile gloves

Area

Any clinical space

Staff

Procedural clinician

Equipment

Kidney dish

Tourniquet (single patient use)

Blood sampling device (e.g. multi-sample needle or butterfly needle)

Vacuum extraction blood tubes

Sterile gauze or cotton wool

Tape

Sharps container

Positioning

Sitting or supine, non-dominant forearm preferred

Inspect forearm starting distally and locate stable, well filled veins away from underlying structures

The preferred site if the cubital fossa, but other sites can be used

Veins of the lower extremities can be used as a last resort or in an emergency

Medication

2ml lignocaine 1% (if local anaesthetic used)

Sequence

Place a tourniquet 5-10cm proximal to venepuncture site

Stroke or tap the vein with your fingers to dilate vein (before skin disinfection)

Consider hanging the arm over the side of the bed or applying a warm compress (if no identified vein)

Using the thumb of the non-dominant hand stretch the skin distally to steady the vein

Insert needle with bevel up at approximately 15 degrees to skin (for superficial veins)

Obtain flashback, flatten the needle and advance slightly into vein

Insert the blood tube (according to the order of draw listed below) with the other hand

Release tourniquet as blood begins to fill the tube (within 1 minute of tourniquet application)

Maintain constant, forward pressure on each blood tube until blood stops flowing (vacuum exhausted)

Cover the venepuncture site with cotton wool or gauze withdraw the needle and apply direct pressure

Post-procedure care

Mix and label blood tubes, and transport for assessment

Apply point pressure to the site of venepuncture for two minutes to minimise bruising (patient may perform)

Advise patient to notify staff of bleeding, pain or swelling

Document insertion

Tips

Dedicate time to optimising patient position and vein palpation to maximise success

Do not touch the planned insertion site after decontamination

Release and reapply tourniquet if applied for more than 1 minute (minimise sampling error)

Inexperienced clinicians should make no more than two attempts at venepuncture except in an emergency

Ultrasound machines and other devices can be useful to assist identifying peripheral veins

Discussion

Blood vacutainers should be drawn in a specific order to minimise sampling error and contamination, the general order is:

Blood cultures

Coagulation (blue)

UEC, LFT, clinical chemistry (yellow then green)

Haematology (pink)

Cross match and group (pink)

Local anaesthetics reduce the pain of insertion and may reduce patient movement, however it can also distort anatomy and itself causes pain. Generally, it is not used for venepuncture, but can be considered on a case by case basis.

Where a patient has a continuous intravenous infusion, blood should be collected from the opposite arm where possible. If the patient has intravenous infusions in both arms, or the other arm cannot be used, blood should be drawn from a vein distal to the infusion, with the tourniquet placed between the IV infusion and the venepuncture site. Accurate basic electrolytes and haematologic values can be drawn from peripheral IV lines when infusions are shut off at least two minutes, at least 5ml of blood is discarded, and tubes are filled to the top to avoid inaccurate bicarbonate readings. Avoid excessive suction on the cannula, which can cause haemolysis.

Peer review

This guideline has been reviewed and approved by the following expert groups:

Emergency Care Institute

Please direct feedback for this procedure to ACI-ECIs@health.nsw.gov.au.

References

World Health Organization. World Health Organization guidelines on drawing blood: best practices in phlebotomy. 2010. 125pp. Available from: https://www.who.int/infection-prevention/publications/drawing_blood_best/en/

Roberts JR, Custalow CB, Thomsen TW. Roberts and Hedges’ clinical procedures in emergency medicine and acute care. 7th ed. Philadelphia, PA: Elsevier; 2019.

Dunn RJ, Borland M, O’Brien D (eds.). The emergency medicine manual. Online ed. Tennyson, SA: Venom Publishing; 2019.

Frank RL. Peripheral venous access in adults. In: UpToDate. Waltham (MA): UpToDate. Accessed June 2019. Available from: https://www.uptodate.com/contents/peripheral-venous-access-in-adults

Nickson, C. Peripheral venous cannulation. Life in the fast lane. 2019. Available from https://litfl.com/peripheral-intravenous-cannula/

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