Venepuncture

Clinical Skills and Simulation teamVersion 1.1 October 2015

Venepuncture

Clinical Skills

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Venepuncture

Aims and Objectives

The aim of this module is to facilitate learning regarding the purpose and procedure ofvenepuncture.

Learning Outcomes

At the end of this session the student should be able to:

Explain the need for venepuncture

Identify the need for care in handling blood samples

Describe the process and importance of labelling blood samples

Demonstrate, to a level expected of the students stage of training, a degree of competencein the procedural steps of venepuncture

Aims and Objectives

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Venepuncture

Introduction

Venepuncture is a common procedure, performed in order to obtain venous blood for investigative or diagnosticpurposes. Results may be compared to an age appropriate range of 'normal' values and to the patient`s previousresults.

As all blood is potentially infective and sharps are used for this procedure, local guidelines for PPE and disposal ofsharps should be followed.

This module will focus on the adult patient and as such a medium sized needle (21 gauge, green) is required. Thisprovides the required flow rate so that a moderate amount of blood may be obtained and stored in samplebottles without clotting.

Introduction

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Venepuncture

Introduction

There are many blood tests (too many to list here), but fortunately there are far fewer bottles than tests. Somecommon tests are:-

urea and electrolytes

full blood count

clotting studies

cross match (you are NOT permitted to take a blood sample for cross match until you have undergone yourblood transfusion training)

You must ensure the correct bottle (colour coded bottle top) is used for each test. The volume of blood requiredper test varies and is marked on the blood bottle itself.

Introduction

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Venepuncture

Anatomy

Veins in the antecubital fossa are most commonly used for venepuncture.

They are usually large

Little variation in anatomy

Less sensitive to pain than other regions

However, there are structures in the antecubital fossa that may be damaged if care is not used, these being:-

Brachial artery

Median nerve

Anatomy

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Venepuncture

Anatomy

Brachial artery

Lies on the medial side of the antecubital fossa, palpate before performing venepuncture inorder to avoid inadvertent puncture.

Median nerve

Usually centrally located and deep to the veins, so care should be taken to avoid damage to thisstructure.

Most appropriate venepuncture site

Lateral side of the antecubital fossa. Ensure the needle is superficial at all times, damage toother structures should be easily avoided.

Anatomy

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Venepuncture

Anatomy - Choice of vein in order of preference

Anatom

1. Median cubital Vein

Most prominent veinWell anchoredSurrounded by fewer nerve endings

2. Cephalic VeinRuns superficially across outer aspects of armLies lateral to the bicep

3. Basilic VeinClose proximity to the brachial artery and median nerve

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Venepuncture

Sites to avoid

In an arm with IV cannula in-situ. The blood sample will be affected by the composition ofthe fluids being given via the cannula. If it is unavoidable and you have to use an arm withan IV canula in-situ you may be required to stop the infusion for a short time before takingthe sample

Avoid using an arm with an arterio-venous fistula present. The fistula is an artificialcommunication between the artery and vein and provides quick access for dialysis. Damageto this structure may prevent the patient from undergoing dialysis

Avoid affected arm in CVA patient (may lack sensation thus potential risk of damagingsurrounding structures)

Avoid affected side in mastectomy patients

Inflammation

Infection

Ezcema

Haematomas

Sites to avoid

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Venepuncture

Equipment

Gather equipment including relevant bloodbottles

Place on clean and stable surface (e.g cleankidney bowl on trolley)

Ensure sharps box is within reach

Ideally use specifically designed tray witharea for small sharps box to be attached

It is recommended that blood collectionbottles are arranged in the order of draw

Equipment

Orange Sharps Box

Vacutainer holder

Blood Bottles

Gloves

Vacutainer Needles

Tray

Tourniquet

Alcohol Gel

Alcohol Wipe

Butterfly Needle

Absorbent Sheet

Blood forms

Tape

Gauze

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Venepuncture

Order of Blood Draw & Mixing Guide

Blood collection bottles have a variety of additives withinthem to allow the laboratory to undertake specific tests

The tube guide informs you of which bottle to use foreach test

The order of draw is the order in which the tubes mustbe filled. If the order is incorrect additives from onebottle can cross contaminate another bottle,subsequently test results may be inaccurate and mayneed repeating

Check number of times the tube should be inverted afterfilling to ensure correct mixing of blood and tubecontents

The Trust you work in will be able to provide the currentcopy of the order of draw

Order of Blood Draw & Mixing Guide

TRUST NAME DISPLAYED HERE

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Venepuncture

Patient Communication

Patient Communication

EExplanation

Explain procedure to patient, include reason for the procedure and anydiscomfort that may be experienced. Include benefits, risks, what will bedone to minimise risks and why the benefits outweigh the risks

CCheck patient identification

Check addressograph details on request form with the patientAsk the patient, if they are able, to tell you their: full name, date of birth &addressIf an in-patient check hospital ID band with request form

I Introduce yourselfGive your name, clinical title and the reason why you have come to seethe patient (e.g. Hello my name is .. I am a junior doctor and …………)

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Venepuncture

Patient Communication

Patient Communication

BENEFITS

Obtain sample to aid diagnosis

Obtain sample for comparison with previous

results to monitor progress

RISKS

Infection

Pain/discomfort

Bruising

Not being able to obtain sample

ACTION TO MINIMISE RISK

Using a technique which includes good skin cleaning

preparation

Having a competent practitioner to perform the

procedure

Applying pressure and keeping a straight arm after needle

withdrawal

Take time in choosing site and will refer to more senior colleague if unsuccessful

Informed Consent

Gain verbal informed consent

Wash hands, apply PPE and gather equipment

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Venepuncture

Procedure

Position your patient

Patient should be sitting or lying down.

You will need to ascertain how the patient feels about blood being taken, some may feel

Faint

Dizzy

Or may be needle phobic

If the patient has previously experienced any of the above or thinks that they may, it is advisableto lie them down. Ensure that you have adequate lighting.

Procedure

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Venepuncture

Procedure

Apply a disposable tourniquet to the upper arm (may be applied over clothing for comfort) a few inches above the antecubital fossa.

The pressure on the arm should bebetween the systolic and diastolic, sothat the veins in the arm distend

It is usual practice to check armpreference with patient

Consider using the non-dominantarm as there may be discomfortexperienced following the procedure

If patient has difficult veins to bleedthe patient may be able to advise onthe best vein to use

The arm should be below the level ofthe heart to help the veins fill

Procedure

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Venepuncture

Procedure

Palpate suitable vein

The vein should be easy to palpate, and should refill rapidly when compressed

*SEEK SENIOR SUPPORT IF UNABLE TO LOCATE A VEIN OR UNSURE WHICH SITE TO USE*

Once site selected undo tourniquet to minimise time pressure applied

Procedure

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Venepuncture

What to do if you are unable to find a vein

Check all sites and take your time

Check both arms and hands if necessary. Take your time in choosing your site before needle insertion. It isbetter to choose the optimal site the first time to minimise the chance of having to repeat the procedure.

Tap

Gently tapping the area releases local histamines which leads to vasodilation and make veins more prominent.

Clench hand into a fist

Ask the patient to make a fist with their hand and release. Repeat a few times. This causes the muscles tocontract and relax, and acts as a pump forcing blood into the veins. Be aware that fist clenching with venousocclusion can cause a false raised potassium measurement which may mask hypokalaemia in the patient.

Warm

If the patient is cold the veins may constrict and be more difficult to bleed. Either wait until they warm up orapply a warm compress to assist vasodilation making the veins easier to see and palpate.

Hydrate

If the patient is even mildly dehydrated the circulating volume will be reduced and thus veins may be harder tosee and palpate.

Unable to Find a Vein

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Venepuncture

Venepuncture

Assemble equipment byremoving the white capfrom needle. This endattaches to the vacutainerholder and punctures thevacutainer bottles

Remember that a sharpneedle is under the softgrey covering. Be aware ofrisk of needle stick injury

Insert this end into plasticvacutainer holder andscrew into place. Do NOTremove needle sheathuntil you are ready toinsert needle intopatient`s vein

Procedure

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Venepuncture

Venepuncture

Place a pillow and absorbent sheetunder patient`s arm

Re-apply tourniquet

Prepare skin by cleaning the areaoverlying the vein with an alcoholwipe. Skin should be in contact withdisinfectant for 30 seconds. Use anoutward spiralling motion starting fromintended puncture site

Allow to dry for a further 30 seconds

Refrain from palpating the vein oncethe area has been cleaned

If you do need to re-palpate youmust re-clean the skin

Procedure

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Venepuncture

Venepuncture

Create skin traction byanchoring vein with your thumbbelow the proposed insertionsite

Insert needle with the bevelupwards, through the skintowards the vein at an angle of35-40°

Procedure

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Venepuncture

Procedure

A loss of resistance will be felt when the needle enters the vein

Advance needle tip 1-2mm into vein, and reduce the angle with the skin

Do NOT ‘dig’ with your needle. You may advance and retract if you are in the incorrect position. However, if the needle is removed completely you MUST use new equipment

NOTE: If you are unsuccessful at introducing the needle into the vein you need to use a new needle for a second attempt and a different site. The generally accepted rule is that each practitioner may have a maximum of 3 attempts before referring to a senior colleague. This depends on the situation, the patient`s condition and consent.

Procedure

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Venepuncture

Procedure

Push blood sample bottle,colour top end first into thevacutainer holder. Ensure youfirmly hold the vacutainerholder so that the action ofpushing on the bottle does notadvance the needle further

The needle will pierce the selfsealing bung on the top of thebottle, and blood will suck intothe bottle due to the vacuum

Keep in place until blood ceasesto flow. Bottles fill until they havethe required amount of blood oruntil the blood flow stops, e.g. theneedle is dislodged

Carefully remove blood bottleand gently invert tube the correctnumber of times

Procedure

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Venepuncture

Procedure

Repeat with other sample bottles if required. Ensure correct order of draw

Remove tourniquet from arm

Remove final blood bottle from vacutainer

Procedure

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Venepuncture

Procedure

Withdraw needle from vein. Once fully removed press on puncture site with a gauze swab

Procedure

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Venepuncture

Procedure

Hold gauze swab on puncture site for 30-60 seconds. The patient can do this if they are able and happy to do so

To minimise bruising keep elbow straight

Patients with clottingproblems, may need to pressfor a longer duration

If patient has bled through thegauze apply a new swab. Applytape to the gauze to secure itbefore leaving the patient

Procedure

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Venepuncture

Procedure

Dispose of sharps immediately and safely into a sharps box

Dispose gloves and apron into a clinical waste bag, as per hospital policy

Return unused equipment and clean your tray/trolley

Wash your hands

Label blood sample bottles whileyou are with patient

Place blood bottles into clear bagsof appropriate request forms, sealand send directly to laboratory

Procedure

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Venepuncture

Procedure

You must document the procedure in the patients medical notes. Your entry must include:

Date & time

Verbal consent obtained

Site used

Equipment used e.g vacutainer system, butterfly needle

Number of attempts

Type of samples obtained. As a student it is advisable to note who requested the samples

Problems or complications

Advice given to patient

Your signature, job role and bleep/extension number. If you work in a Trust which provides staff ID stamps you must also add this

Documentation

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Venepuncture

Tips

Once the vein is punctured keep the non-dominant hand as still as possible. Even slightmovement will displace the needle from the vein. This is more of a problem if large volumesof blood are required. If you find this difficult, try using a “Butterfly” to aspirate the blood.This is a small needle with side flaps which give an appearance of a butterfly and it hasattached tubing running from the needle. The needle can be fixed to the skin via the plastic“Butterfly”, which enables both hands to be freed up for attachment of the blood bottle tothe vacutainer without needle displacement.

For some samples (notably calcium estimates), a tourniquet should not be used during bloodaspiration. Plasma calcium is largely bound to serum albumin, which concentrates in venousblood when a tourniquet is applied. This may lead to an over-estimation of the plasmacalcium levels. Use the tourniquet to identify the vein, insert the needle, then release thetourniquet before aspirating the blood. You are more likely to be successful if the arm isbelow the level of the heart, allowing gravity to dilate the arm veins.

Tips

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Venepuncture

Other Important Things

Four important things the WHO does not want us to do…….

1. Re-sheath a used needle with two hands i.e. holding sheath in one hand and needle in the other.

2. Recap used vacutainer needles and disassemble them from the holder.

3. Re-use tourniquets and vacutainer holders.

4. Work alone with patients who may move unexpectedly and thus increase the risk of needle stick injury e.g. confused patients and paediatric patients.

Important things Cardiff University wants you to remember…….

1. As medical students you must practice under supervision.

2. Venepuncture is a practical skill that the GMC requires you to do competently. You must be signed off as competent in your practical skills log before graduating.

3. Performing a cross match blood sample is another practical skill that the GMC requires you to do competently before graduating. However you must successfully undertake your blood transfusion training before performing this procedure.

Other Important Things

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Venepuncture

Video Summary

(Not available in PDF)

Video Summary

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Venepuncture

Checklist

Introduce yourself, explain procedure to the patient and seek consent

Apply tourniquet to upper arm

Select vein

Apply gloves and apron

Clean patient’s skin carefully using appropriate preparation and allow to dry

Do not re-palpate vein or touch skin at puncture site

Create skin traction by anchoring vein with your thumb below the proposed insertion site

Insert needle smoothly at an angle of 35-40°

Level off needle when puncture of the vein wall is felt

If possible, advance needle a further 1-2 mm into vein

Do not exert pressure on needle .

Withdraw required amount of blood using Vacutainer system

Release tourniquet

Place sterile gauze swab over puncture point

Checklist

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Venepuncture

Checklist

Do not apply pressure until needle is fully removed

Apply pressure until bleeding stops

Invert tubes to allow adequate mixing

Label bottles with relevant details

Inspect puncture point before applying dressing. Check for known allergies

Apply adhesive plaster or alternative dressing

Discard waste in correct containers, e.g. sharps into sharps box

Wash hands

Checklist

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Venepuncture

World Health Organisation (2010) WHO guidelines on drawing blood:

best practices in phlebotomy

http://www.who.int/injection_safety/phleb_final_screen_ready.pdf

Akunjee et al (2012) Clinical Skills Explained Cambridge: Scion Publishing Ltd

References

References

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