At a glance: a guide to venepuncture in adults

Venepuncture is a vital procedure that is routinely used in the care and management of patients and is one of the most commonly performed invasive procedures (Boyd, 2022). It enables health professionals to obtain a sample of blood for analysis by the puncture of a vein with a hollow-bore needle, vacuum system or butterfly infusion system (Thomas, 2015). These investigations typically include biochemical to analyse certain parameters, such as potassium and sodium levels, haematological to determine blood measurements and microbiological to determine the presence of pathogens (Gallagher, 2022). As this is a procedure that nurses may be asked to perform as part of their role, it is essential that they are adequately trained, competent in using the correct technique and aware of any advances or changes in the underpinning evidence (Nursing and Midwifery Council (NMC), 2018)

Aseptic non-touch technique

The aseptic non-touch technique (ANTT) is a method employed to minimise the likelihood of patients contracting infections during clinical procedures. As set out by the Association for Safe Aseptic Practice (ASAP) (2021) it accomplishes this by safeguarding ‘Key-Parts’ and ‘Key-Sites’ from micro-organisms that might be transmitted from health personnel or nearby environments. ‘Key-Sites’ are classified as parts of the body into which infection might be introduced during a procedure, eg opening in the skin, urethra, cannula insertion site; whereas ‘Key-Parts’ are associated with the equipment that might come into contact with Key-Sites or other Key-Parts, eg, dressings, catheters and syringe tips. These should not be touched or only touched with sterile gloves and sterile equipment.

There are two main variations of ANTT: standard, which is used for uncomplicated, simple and quick procedures involving few Key-Sites or Key-Parts, and surgical, for those skills and procedures that are more complex, lengthy and involve multiple Key-Sites or Key-Parts. When carrying out a clinical procedure, an ANTT risk assessment is required to ascertain if the procedure necessitates the adoption of a standard or surgical ANTT approach. This involves assessing the difficulty of protecting the Key-Parts and Key-Sites associated with the skill, while also considering the number and sizes of the Key-Parts, environment, invasiveness, and user competency (ASAP, 2021). For standard ANTT procedures, non-sterile gloves can be worn as the Key-Parts and Key-Sites are limited, such as in cannulation and venepuncture. However, for surgical ANTT procedures such as urinary catheterisation and wound care, sterile gloves must be worn, due to the level of invasiveness (ASAP, 2021).

Informed consent, patient preparation and pain management

Before carrying out venepuncture, and where possible, it is necessary to obtain informed consent. This will include ensuring that patients are aware of the reasons for the need to take samples of their blood, what the associated risks and complications are and details of the procedure and aftercare (Curr and Fordham-Clarke, 2022). Providing this level of information will not only safeguard that the patient can provide valid consent, but will also assist in building rapport and a trusting therapeutic relationship, which could help reduce any fears or anxieties. It is also imperative at this point to gauge how the patient is feeling about the procedure, as gaining an insight into potential fears, (eg fear of needles – trypanophobia) (Perry et al, 2021), anxieties or preferences will allow for adequate preparation of the patient and the environment prior to the procedure. This can be achieved by asking questions such as ‘Have you had this procedure before?’ and ‘How do you feel about the procedure?’. Any potential allergies also need to be determined before gathering the equipment, as alternative gloves and dressings may be required.

It is also important to consider not only the patient's comfort but also the potential to increase their pain, thus appropriate multimodal approaches to pain assessment and management need to be undertaken in order to minimise the risks of harm. This can include the use of pharmacological and non-pharmacological approaches such as distraction therapy and topical analgesics (Ford, 2019).

Anatomy of the arm

When undertaking venepuncture, it is important to understand the anatomy and physiology of the veins, circulation and surrounding structures (arteries and nerves), in order to undertake safe and effective practice (McCall, 2020). The superficial veins (median cubital, cephalic, and basilic) found in the antecubital fossa region of the arms, are the most commonly selected sites for venepuncture (Figure 1a), as they are easily accessible and cause minimal discomfort for the patient (Brooks, 2017). Metacarpal veins (Figure 1b) can also be used as they are easy to visualise, and palpate; however, the use of these veins may be more painful and difficult in patients with poor skin turgor (McCall, 2020).

Choosing the correct site and vein

Although the arm is the most commonly used site for venepuncture, it is important to assess the most appropriate site for each patient. Factors that influence the decision include patient preference, past medical history, age, current comorbidities, skin condition, vein suitability and accessibility and reasons for use (Gorski et al, 2021). Additionally, it is essential to consider which arm or limb to use, which vein to select within that limb and then which particular site on the skin (see Table 1).

Equipment

There is a wide variety of hollow-bore needles and vacuum systems that are available for venepuncture; therefore, it is imperative that you familiarise yourself with the equipment that is used by your trust. See Box 1 for an example list of the equipment that is required.

Box 1.Sample equipment list for venepuncture

• Gloves
• Apron
• Alcohol gel
• Procedural tray
• Disposable tourniquet
• Alcohol-based cleansing product
• Needle
• Tube holder
• Vacuum blood collection tubes
• Sterile gauze
• Dressing or adhesive tpe
• Sharps disposal bin
• Request forms (signed, dated and labelled)
• Pillow

Source: Lister et al, 2021

Blood collection tubes and order of draw

Traditionally, blood samples were obtained by needle and syringe, but advances in technology and medical devices led to this being superseded by vacuum blood collection tube systems (Blann and Ahmed, 2014). These glass or plastic tubes contain a partial vacuum, which encourages the movement of blood from the vein into the tube, and the amount of vacuum present will determine the amount of blood required within the container (Lister et al, 2021). The tubes also contain additives, such as anticoagulants (eg, sodium citrate, lithium heparin) or substances to allow a serum sample to be obtained, and which additive is used is dependent on which analysis techniques are to be conducted in the laboratory (Blann and Ahmed, 2014). In order to mix the blood with the contents, the tubes must be inverted, and the number of inversions will depend on the manufacturer's instructions (Lister et al, 2021). It is also essential that the additives within the various tubes are not mixed with each other and therefore if more than one tube is to be used, these must be used in a specific order (Thomas, 2015). Higgins (2013) suggested that within the blood analysis continuum, errors during the collection of the samples are where the most errors occur. Order of draw protocols should, therefore, be adhered to.

Tourniquets

In nursing practice, tourniquets can be used as a means of maximising successful attempts on first insertion (Shaw, 2014). Several types can be found in practice, these should be disposable, easy to use and latex-free (Lister et al, 2021). When applying the tourniquet, it is also imperative that it is removed as soon as possible (not exceeding 60 seconds) as the tourniquet will cause venous stasis, localised acidaemia and haemoconcentration, which affect the blood for analysis (Higgins, 2013; Pagana et al, 2020). Consequently, Gorski et al (2021) do not advocate the use of a tourniquet, stating that it should be avoided if possible. Therefore, practice may differ, and it is imperative that you abide by local trust policy when deciding if a tourniquet is to be used.

Site preparation

Although there is some controversy about whether skin cleansing of the site is necessary, the Infusion Nurses Society guidelines (Gorski et al, 2021) state that skin antisepsis should be performed prior to all venepunctures to prevent the risk of infection. It can be prepared with a cleansing agent that is alcohol-based, such as 70% isopropyl alcohol or 2% chlorhexidine in 70% alcohol (Loveday et al, 2014). The technique for how the skin should be prepared must be in accordance with the manufacturers' instructions, which will be specific to the products being used.

Risks and hazards

As with any clinical procedure, the trained health professional must be aware of the risks involved, for themselves, the patient and others. Further details in relation to blood-borne infection, sharps safety, phlebitis, arterial puncture and extravasation can be found in the accompanying article entitled ‘A guide to cannulation in adults’ (Ford, 2023).

Safety of the practitioner

One of the greatest dangers to health professionals when undertaking procedures using hollow-bore needles is the risk of contracting a blood-borne infection via a sharps injury (Health and Safety Executive, 2013). Due to the frequency of undertaking venepuncture, nurses are one of the health professional groups most at risk (Woode et al, 2015). Health professionals can be exposed to 30 potentially dangerous pathogens, including hepatitis B and C (European Biosafety Network, 2011). Therefore, in order to ensure safe practice, personal protective equipment (PPE), which is a universal precaution, must be worn. Kinlin et al (2010) claimed that the use of gloves has been shown to be beneficial in reducing the transmission of blood-borne infections by decreasing the inoculum of blood introduced during a sharps injury. Additionally, all devices used must adhere to sharp safety regulations, must be checked before use, as instructed by the manufacturers and disposed of correctly (Health and Safety Executive, 2013).

What is the correct procedure for venepuncture?

As health professionals, it is important to work within guidelines and policies and use evidence-based practice (Nursing and Midwifery Council (NMC), 2018). The use of a standard ANTT for the preparation and performance of the procedure can minimise the risk of contamination and risk of infection (Loveday et al, 2014):

• Communicate with the patient, gain informed consent and ascertain preferences, allergies and fears
• Decontaminate hands and gather and assemble relevant equipment (Figure 2a)
• Place the limb in a comfortable, accessible position (use a pillow if necessary)
• To assess which vein to use, a tourniquet can be used to make the veins more visible. Make sure the tourniquet is appropriately applied 7-10 cm above the chosen site. However, it should only be tight enough to impede venous return and not obstruct arterial flow. Asking the patient to open and close their fist, or using gravity and hanging the patient's arm down, may also encourage venous filling
• Palpate with two fingers or the thumb, to find the best available vein (Figure 2b). NB veins do not pulsate
• Decontaminate hands and apply PPE (Ford and Park, 2018; 2019)
• Clean the chosen site with the alcohol-based preparation equipment and allow it to dry (Figure 2c). Do not re-palpate, as this will increase the risk of contamination
• Remove the sheath from the needle and inspect for damage
• Warn the patient they will feel a sharp scratch
• Use one hand to apply traction on the skin a few centimetres below the site and avoid touching the clean area (Figure 2d)
• With the bevel upwards, insert the needle at about a 10-30 degree angle (this will vary depending on the manufacturer's guidelines). Some needle equipment will allow you to see if you are correctly situated in the vein with a visual flashback – if this is not the case, you will have to attach the vacuum collection tube to observe for successful blood flow
• Attach the vacuum collection tube to the device connected to the end of the needle (plastic holder) (Figure 2e)
• Allow the required blood for that specific collection container to be collected, and as soon as blood runs freely, release the tourniquet (Figure 2f)
• Remove the vacuum collection tube and invert as per manufacturer's instructions
• Once all the required blood has been obtained, hover the gauze over the needle site (do not press down yet)
• Retract the needle and put pressure on the site with the gauze
• Click the safety cap (over the needle) with your thumb and dispose of it in the sharps container
• Remove PPE, wash hands, label specimens and document the care, noting any witnessed difficulties.

Top tips

The following information has been collated by Northumbria University staff in relation to some of the common errors that students encounter when undertaking venepuncture.

• Missed vein: ensure you use your fingers to anchor the vein, this will stop the vein from moving and will also stretch the skin for better visibility. If you also choose one of the largest veins, then the likelihood of missing the vein will be reduced
• Blood spray: ensure you advance the needle tip far enough into the vein, if the tip has entered before the rest has advanced under the skin, you have only achieved partial needle insertion, and leakage may occur. Avoid superficial veins to help reduce the likelihood of this occurring
• Blood stops flowing: this is probably due to the angle of insertion or if the tip of the needle has made contact with a valve, the vein wall or if the vein has collapsed. To remedy this, gently advance or reposition the needle
• Spatter of blood that then stops: you have possibly pushed the needle too far, and it has exited the vein on the posterior side. Remove the needle and apply pressure
• Simulation-based education (SBE) is a widely used teaching method in healthcare education that uses patient simulators, task trainers (such as those used in the images in Figure 2) and virtual technologies. It has been proven to be an effective way to support clinical placement, prepare health professionals for their future work, and address the necessary qualities and proficiencies that nurses and other health professionals need to possess, and improves knowledge and behaviours, particularly related to clinical skills, when compared with traditional training techniques (NMC, 2023).

Conclusion

Venepuncture is a clinical skill, which requires health professionals to have a sound understanding of the underpinning principles, as well as a comprehensive awareness of the technique aligned with the clinical procedure. Therefore, although it is important to review local and national guidelines and associated literature, it is also vital to use every opportunity to practise this skill in clinical practice, in addition to using alternative education and learning strategies such as simulation-training aids, in order to maintain contemporary practice.

KEY POINTS

• Venepuncture is a widely practised invasive procedure, which uses an aseptic non-touch technique and requires a sound understanding of anatomy and physiology
• This skill is associated with several risks for both health professionals carrying out the procedure and the individual who requires the intervention
• For students, the opportunity to practise this skill in clinical practice is sometimes difficult; therefore, alternative education and learning strategies such as simulation can prove extremely beneficial in acquiring and maintaining practice

CPD reflective questions

• What anatomical knowledge and patient assessment skills do you need to consider essential before attempting venepuncture? How does this knowledge help in reducing the risks associated with this procedure?
• How do you ensure the proper selection and utilisation of equipment, and are there any recent advancements in equipment that you should be aware of and incorporate into your practice?
• In your practice, how do you effectively communicate with patients about the procedure, obtain informed consent, and provide them with information about potential risks? How can you improve your patient communication and education regarding venepuncture?