Peripheral cannulation procedure

Procedure
Wash your hands before gathering the equipment and before touching the patient. Ensure that ANTT is maintained throughout the procedure.	Gather the equipment and check dates and seals. Put on a disposable apron and wash your hands. Check the pre-filled 0.9% sodium chloride flush with a colleague or, if drawing the flush up, ensure you follow the local policy for IV drug administration and check the 0.9% sodium chloride ampoule with a colleague.
Check your hands for any broken skin and, if necessary, cover with a dressing. Approach the patient, cleanse your hands using alcohol hand gel and ensure the patient is in a comfortable, safe position to enable safe cannulation. Ensure the sharps bin is located nearby for safe disposal of sharps.	Assess the patient’s skin and veins on both arms. Undertake a visual assessment of the skin in the areas you are considering for cannulation. Avoid areas with oedema, eczema, redness or bruising. Make note of the veins that you can see.
Place a tourniquet 3-4 fingers (7-8cm) width away from the proposed cannulation site. Tighten the tourniquet, ensuring the radial pulse can be felt.	Assess the veins by palpating them with the tips of your fingers, not the thumb. Stretch the skin gently to anchor the vein. Try not to look initially, because this will reduce your sense of touch. Assess the suitability of the vein for the cannula and drug, feeling for a pulse. If a pulse is felt, then it is an artery, so move away.
Check if the vein bounces or if it is hard. Check if there is a valve, which will feel like a pea or thickening that does not bounce. Ascertain the direction of blood flow in the vein, as well as the length of the vein, how deep it is and whether it is near a joint. Assess both arms, if required. If a suitable vein is found on the first arm to be assessed, then this can be cannulated. Select the vein and release the tourniquet. Cleanse your hands using alcohol hand gel.	Open the cannulation pack, if used and organise all the equipment. Alternatively, open the packs of the individual components, such as the cannula, dressing, and pre-filled syringes and place them on the ANTT tray. Ensure that the essential parts, for example, the cannula and syringe tips are not left exposed. Remove the covers, for example, take the protective stylet guard from the cannula, just before use, and ensure the essential parts are not touched. Prime the needle-free access device. Clean the hub with a 2% chlorhexidine in 70% isopropyl alcohol wipe if it has been touched before priming.
Figure 1 Re-apply the tourniquet. Cleanse your hands with alcohol hand gel. Palpate the vein if required before cleaning the skin. Clean the skin at the insertion site and the surrounding skin with 2% chlorhexidine in 70% isopropyl alcohol solution. Activate the applicator using gentle pressure and a back and forth movement for 30 seconds (Figure 1), and allow to dry for 30 seconds. Do not re-palpate the vein (Dougherty and Lister 2015).	Figure 2 Landmark the insertion site in your mind or use sterile gauze to point to the insertion site, ensuring the gauze is not placed directly on the insertion site (Figure 2). Ensure you only touch the part of the gauze that will be away from the insertion site (Figure 2). Put on non-sterile gloves. Inspect the needle for any faults.
Figure 4 Figure 3 Take hold of the cannula, ensuring the stylet does not move. Check the stylet is bevel up. If it is not, discard the cannula, because this indicates there has been some movement of the stylet in the cannula. Flatten the cannula wings (Figure 3). Hold the cannula in your dominant hand, using a hold that will ensure the stylet does not move and will allow insertion at the correct angle, as well as allowing the angle to be reduced (Figure 4).	Figure 5 Anchor the skin throughout the procedure and insert the stylet with conviction at an angle of 10-40 degrees (Figure 5), dependent on the type of cannula and the site (Brooks 2014).
Figure 7 Figure 6 Once the stylet tip is in the vein, the first flashback of blood will be seen (Figure 6). Report any concerns, such as bleeding or signs of sub-optimal perfusion to the hands or digits, immediately to the clinician responsible for the patient’s care. Lower the cannula angle and advance the cannula a few millimetres (Figure 7) (Brooks 2014).	Figure 8 With your dominant hand, grip the stylet guard between your thumb and forefinger (Figure 8) and move back slightly. A second flashback of blood will be seen entering the cannula (Figure 8). This confirms that the cannula is in the vein.
Figure 9 Keep hold of the stylet guard with your dominant hand, pincer grip the wing with your non-dominant hand and advance the cannula further into the vein (Figure 9).	Figure 10 Move back with the dominant hand so the stylet sits in the cannula hub (Figure 10). With your non-dominant hand, place the thumb on the wing and index finger occluding the vein above the cannula tip, and release the tourniquet with your dominant hand (Figure 10). Remove the stylet and dispose of it in the sharps bin. Attach the needle-free access device.
Secure the cannula using dressing tape and flush with 5mL of 0.9% sodium chloride. Observe for pain, swelling or wetness at the insertion site. Apply hub protectors, as per local policy. Hub protectors should be discarded after the next access, and new hub protectors put on after each access.	Apply the transparent cannula dressing. Dispose of waste and ensure that the patient is comfortable.

Figures 1-10: ©Sally Jane Shaw

1. Up to 70% of hospitalised patients undergo peripheral cannulation (Zingg and Pittet 2009).
2. Before undertaking peripheral cannulation the need for a cannula should be explained to the patient, and their consent obtained.
3. Wash your hands before checking the equipment and cleanse them using alcohol gel before approaching the patient.
4. Assess the patient’s skin and veins on both arms visually first and then by tightening a tourniquet around the proposed cannulation site. Release the tourniquet once an unbounced vein with good blood flow is found and then organise the equipment.
5. To landmark the insertion site, re-apply the tourniquet, palpate the vein and clean the skin using gentle pressure. Once the stylet is inserted at the correct angle, flashback of blood is seen twice going into the cannula.
6. Release the tourniquet once the cannula is further advanced into the vein ensuring the stylet sits in the cannula hub. Remove the stylet and secure the cannula to flush 0.9% sodium chloride.

Evidence base

Up to 70% of hospitalised patients undergo peripheral cannulation (Zingg and Pittet 2009). Moureau et al (2012) stated that there are barriers to vascular access selection, including healthcare practitioner knowledge, vessel preservation and cannula selection.

Successful cannulation is based on patient well-being, knowledge of their medical history and condition, vascular access history, the proposed IV therapy, vein selection and ongoing care and management. Ensuring patient well-being pre-cannulation and during the procedure is the first step.

Mackereth and Tomlinson (2014) suggested that, while consent is vital, the language used before cannulation is also essential to the success of the procedure. If practitioners use negative language, such as ‘poor veins’, or ‘sharp scratch coming’, this can increase patient anxiety (Mackereth and Tomlinson 2014). These terms project negativity and can cause the patient to feel ashamed.

It is important to demonstrate a positive manner and language when assessing a patient’s veins and during the procedure. It is also important to involve the patient at each stage. Mackereth and Tomlinson (2016) suggested that the use of positive actions and language that do not focus on reminding the patient that the cannula is absolutely necessary, will improve success. Using positive language and attitude, for example ‘I am going to use my skills to find a fabulous vein’ (Mackereth and Tomlinson 2016) will reduce the patient’s stress and thus improve cannulation.

Use of the vessel health and preservation (VHP) framework (Hallam et al 2016) will assist in the vein assessment process and choice of devices. The patient’s age, size and any history of failed attempts should be considered (Carr et al 2016), because these can all contribute to insertion failure.

It is vital that the optimal vein and cannula size are selected to reduce the risk of complications. This is dependent on the size of vein, what is to be administered and the speed of administration. A study by Wallis et al (2014) confirmed that a ≤ 18 gauge cannula (18 gauge, 16 gauge, 14 gauge or larger) predicts failure as a result of phlebitis. This study also identified an increased risk of occlusion of a cannula that is inserted in the hand or antecubital fossa when compared to the forearm. This evidence supports the use of veins in the forearm for cannulation.

ANTT must be maintained throughout the procedure, because cannulation breeches the body’s natural defences (Loveday et al 2014). Skin at the insertion site is decontaminated using a single-use application of 2% chlorhexidine in 70% isopropyl alcohol (or povidone iodine in alcohol for patients with sensitivity to chlorhexidine), and allowed to dry (Loveday et al 2014). Using an applicator will reduce the risk of the site being contaminated by the practitioner’s hand. Correct skin preparation reduces the risk of infection gaining access via the insertion site.

When handling the cannula, it is vital the stylet does not move back into the cannula before cannulation. If this occurs, there is the potential for the stylet to fracture the cannula, which, if inserted, might break off once inside the vein. This would potentially cause serious harm to the patient if the fractured cannula moved to the heart or lungs.

On insertion, the first flashback of blood will be seen just behind the stylet guard in the flashback chamber. This confirms venepuncture has been successful and the stylet is in the vein. Lowering the angle and advancing a few millimetres ensures the stylet does not transfix the vein, and enables the cannula to be advanced into the vein (Brooks 2014). Moving the stylet back slightly enables the second flashback to be seen, confirming the cannula is in the vein.

It is worth being aware that some cannulae are able to provide an immediate secondary flashback, because the blood is able to travel up the body of the cannula on insertion. This controlled technique reduces the risk of damage to the endothelium and hence reduces the risk of phlebitis. Insertion of a 20-gauge cannula in the forearm further reduces the risks of phlebitis (Wallis et al 2014). This demonstrates that it is vital that the correct gauge cannula in relation to vein size is used.

Effective occlusion of the vein at the end of cannulation will ensure blood does not flow back into the needle-free access device and therefore reduces the risk of infection. Flushing the cannula provides further confirmation that the cannula is in the vein.

To flush the cannula, initially use 5-10mL of 0.9% sodium chloride. Clean the top of the hub with a 2% chlorhexidine in 70% isopropyl alcohol wipe for 30 seconds and allow to dry for at least 15 seconds (Loveday et al 2014). Flush the device using a slow constant pressure for the first 1-2mL then use a push/pause technique to create a turbulence flow in the device, ensuring it is flushed effectively, thereby reducing the risk of fibrin sheath formation and infection Moureau 2012).

As the syringe plunger reaches 0.5mL of flush, maintain pressure on the syringe and clamp the needle-free device. This creates a positive pressure to reduce the risk of reflux of blood into the cannula and hence reduces the risk of occlusion. The positive pressure technique is used with needle-free access devices that create a negative pressure.

Practitioners should be aware of what type of needle-free access device is in use in their clinical area, because needle-free access devices might produce a negative pressure or a neutral pressure. Neutral pressure does not require a clamping sequence. Practitioners should always refer to the manufacturer’s guidance on needle-free access devices, along with local policy.

When flushing, observe for pain, swelling under the skin or wetness at the insertion site. If any of these are observed, this indicates that the cannula is not in the vein and that it is vital that the practitioner removes the cannula to avoid infiltration or extravasation injuries, which result from IV fluids and medications entering the tissue surrounding the vein. If the flush is not facilitated with gentle pressure, first check that you have released the clamp on the needle-free access device. If difficulty persists, remove the cannula.

Once the cannula has been flushed, secure it in place with a sterile transparent cannula dressing (Loveday et al 2014). Practitioners must document the insertion of the cannula and ongoing care. Ongoing care of the cannula is paramount. A cannula should be observed a minimum of once per shift, documenting the visual infusion phlebitis score and, if not in use, the cannula should be flushed with 5mL of 0.9% sodium chloride at least once per shift (Loveday et al 2014).

The cannula should remain in place (dwell time) until removal is clinically indicated, or as otherwise stated by the manufacturer (Loveday et al 2014). Blood withdrawal should be considered part of ongoing care and assessment to confirm a cannula is in place before use.

Fidalgo et al (2012) stated that a flashback of blood should be seen before commencing IV drug administration. It is important that this forms part of the full assessment of the cannula, for example wetness or pain on flushing would indicate removal of the cannula regardless of blood flashback. It is important to consider that flashback of blood does not, on its own, indicate the cannula is in the vein, because there may be residual blood in the cannula.

The Infusion Therapy Standards of Practice state that a cannula’s function is assessed by flushing and aspiration for a blood return before each intermittent cannula use and as clinically indicated with continuous infusions, such as by an occlusion alarm (Infusion Nurses Society 2016). The Royal College of Nursing Intravenous Therapy Standards were published in 2016 and may provide further guidance, along with local policies.

Cannulation is a common but important aspect of patient management; therefore, it is crucial to ensure best practice in undertaking this procedure, to provide optimal patient care.

Learning points

1. It is important to use positive language and have a positive attitude when assessing a patient’s veins and during the procedure as this will help reduce the patient’s anxiety.
2. A patient’s age, size and vascular access history should be considered in the vein assessment and device selection process as this will reduce the risk of complications.
3. On insertion, the first flashback of blood will be seen just behind the stylet guard in the flashback chamber. Lowering the angle to advance the cannula into the vein and moving the stylet back slightly enables the second flashback to be seen. This controlled technique reduces the risk of damage to the endothelium.
4. Once the cannula has been flushed it should be secured with a sterile transparent cannula dressing. Ongoing care is important, which includes observation of site a minimum of once per shift, documenting the visual infusion phlebitis score, and if not in use the cannula should be flushed with 5mL of 0.9% sodium chloride at least once per shift.

Disclaimer: Please note that information provided by RCNi Learning is not sufficient to make the reader competent to perform the task. All clinical skills should be formally assessed at the bedside by a nurse educator or mentor. It is the nurse’s responsibility to ensure their practice remains up to date and reflects the latest evidence.

Useful resources

• AVATAR Group www.avatargroup.org.au
• European Society for Medical Oncology www.esmo.org/Guidelines/Supportive-Care/Management-of-Chemotherapy-Extravasation
• Infection Prevention Society website www.ips.uk.net
• National Infusion and Vascular Access Society – NIVAS www.nivas.org.uk
• Royal College of Nursing (2016) Standards for infusion therapy. Fourth edition. www.rcn.org.uk/professional-development/publications/pub-005704

References

Brooks N (2014) Venepuncture and Cannulation: A Practical Guide. M&K Publishing, Keswick.

Carr PJ, Rippey JCR, Cooke ML et al (2016) Development of a clinical prediction rule to improve peripheral intravenous cannulae first attempt success in the emergency department and reduce post insertion failure rates: the Vascular Access Decisions in the Emergency Room (VADER) study protocol. BMJ Open. doi: 10.1136/bmjopen-2015-009196. 26868942

Dougherty L, Gull K (Eds) (2015) Vascular access devices: insertion and management. In Dougherty L, Lister S (Eds). The Royal Marsden Manual of Clinical Nursing Procedures. Ninth Edition. Wiley Blackwell, Chichester, 861-933.

Fidalgo JAP, Fabregat L, Cervantes A et al (2012) Management of chemotherapy extravasation: ESMO-EONS Clinical Practice Guidelines. Annals of Oncology. 23, Suppl 7, vii167-vii173. 22997449 10.1093/annonc/mds349

Hallam C, Weston V, Denton A et al (2016) Development of the UK Vessel Health and Preservation (VHP) framework: a multi-organisational collaborative. Journal of Infection Prevention. 17, 2, 65-72. 10.1177/1757177415624752 CROSSREF

Infusion Nurses Society (2016) Infusion Therapy Standards of Practice. Journal of Infusion Nursing. 39, Suppl 1, S1-S159.

Loveday HP, Wilson JA, Pratt RJ et al (2014) epic3: national evidence-based guidelines for preventing healthcare-associated infections in NHS hospitals in England. Journal of Hospital Infection. 86, Suppl 1, S1-S70. 24330862 10.1016/S0195-6701(13)60012-2CROSSREF