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Pre‐procedural considerations

Safety of the practitioner

It is recommended that well‐fitting gloves are worn during any procedure that involves handling blood and body fluids, particularly venepuncture and cannulation (NHS England and NHSI [155], RCN 2017b). This is to prevent contamination of the practitioner from potential blood spills. While it is recognized that gloves will not prevent a needle stick injury, the wiping effect of a glove on a needle may reduce the volume of blood to which the hand is exposed, thereby reducing the volume inoculated and the risk of infection (NHS Employers [154]). However, there is no substitute for good technique and practitioners must always work carefully when performing venepuncture.

A range of safety devices are now available for venepuncture that can reduce the risk of occupational percutaneous injuries among healthcare workers, in particular vacuum blood collection systems (see Figure 13.6) (Garza and Becan‐McBride [66]). Regulations require the use of safer sharps systems that incorporate protective mechanisms such as safety shields or covers. Where practical, all conventional devices are to be replaced (HSE [96]). Used needles should always be discarded directly into an approved sharps container, without being re‐sheathed (DH [48], McCall and Tankersley [138]). The accompanying request forms should be kept separately from the specimen to avoid contamination (HSE [94]). All other non‐sharp disposables should be placed in a universal clinical waste bag or discarded in accordance with local policy.

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Figure 13.6 A vacuumed collection system: two blood culture bottles, a Vacutainer holder and a Vacutainer ‘butterfly’.

Equipment

Tourniquets

There are several types of tourniquet available. A good‐quality, buckle‐closure, single‐hand‐release type is most effective but the choice will depend on availability and operator. Consideration should be given to the type of material and the ability to decontaminate the tourniquet. Fabric tourniquets that cannot be cleaned are not recommended (RCN [203]). Disposable tourniquets are recommended and are available for single use and should be discarded immediately after use, especially where there is potential for microbial cross‐contamination (RCN [203]). A blood pressure cuff can be applied instead of a tourniquet as it will apply pressure over a wider area and make the veins more prominent. The cuff should be inflated half way between the diastolic and systolic readings. The need for disposable cuffs should also be considered where cross‐contamination may occur.

Needles

The intravenous devices commonly used to perform a venepuncture for blood sampling are a straight steel needle and a steel winged infusion device. The optimum gauge to use is 21 swg (standard wire gauge), which measures internal diameter: the smaller the gauge size, the larger the diameter. This enables blood to be withdrawn at a reasonable speed without undue discomfort to the patient or possible damage to the blood cells (Garza and Becan‐McBride [66]).

Vacuum systems

A vacuum system consists of a plastic holder that contains or is attached to a double‐ended needle or adapter (Figure 13.6). It is important to use the correct Luer adapter to ensure a good connection and avoid blood leakage (Garza and Becan‐McBride [66]). The blood tube is vacuumed in order to ensure that the exact amount of blood required is withdrawn when the tube is pushed into the holder. Filling ceases once the tube is full, which removes the need for decanting blood and also reduces blood wastage. The system can also be attached to winged infusion devices (WHO [257]).

A number of vacuum systems can be used for taking blood samples. These are simple to use and cost‐effective. The manufacturer's instructions should be followed. Vacuum systems reduce the risk of healthcare workers being contaminated, because they offer a completely closed system during the process of blood withdrawal. This makes them the safest method for collecting blood samples.

Blood collection tubes are available in various sizes and have different‐coloured tops depending on the type of additive. The colour coding of the tops is generally universal but may vary depending on manufacturer. Local policy must be referred to in order to select the correct tubes for specific tests. Blood tubes should be used in a sequence referred to as the ‘order of draw’ to minimize the transferring of additives. The correct volume of blood should be collected into each tube to prevent erroneous results (Table 13.4). The expiry dates on the tubes should also be monitored regularly.

Table 13.4 Blood collection tubes and draw order

Tube	Type	Determinations	Instructions
Blood culture	Blood cultures	Blood cultures	Aerobic followed by anaerobic – use aerobic bottle only if not enough blood for both bottles
Light blue	Sodium citrate	PT, PTT, INR, APTT, D‐dimers, fibrinogen, clotting screen, factor assays, thrombophilia screen (four light blue tubes and one EDTA tube), lupus (three light blue tubes), anticoagulant	Fill tube completely and invert tube gently three or four times
Red	No additive	Antibiotic levels, steroid hormones, B₁₂	No need to invert tube
Gold	Clot activator and serum separator	Routine chemistry, lipids, thyroid (TFT), drug levels including lithium, proteins Supply additional tube for troponin I levels Does not do glucose, lactate or alcohol	Invert six times
Green	Lithium heparin	Chromosome studies	Invert 8–10 times
Lavender	EDTA	Haematology: FBC, sickle screen, haemoglobin, electrophoresis, red cell folate, malaria, lead, mercury, thalassaemia, PTH, ESR Biochemistry: cyclosporin and other drugs	Invert 8–10 times
Pink	EDTA Cross‐match	Antibody and group screen	Invert 8–10 times
Grey	Fluoride oxalate	Alcohol, glucose, lactate	Invert 8–10 times
Black	ESR	ESR	Invert 8–10 times
Royal blue	Trace elements	Trace elements, manganese, zinc, whole blood	Invert 8–10 times

APTT, activated partial thromboplastin time; EDTA, ethylenediamine tetra‐acetic acid; ESR, erythrocyte sedimentation rate; FBC, full blood count; INR, international normalized ratio; PT, prothrombin time; PTH, parathyroid hormone; PTT, partial thromboplastin time; TFT, thyroid function test.

Source: Adapted from Dojcinovska ([51]) with permission of John Wiley & Sons, Ltd.

The equipment available will depend on local policy (Table 13.5). However, given increasing concerns about the possibility of contamination of practitioners, blood collection systems with integrated safety devices are now readily available and should be used for all procedures (HSE [96], RCN [203]). However, the nurse must always select the device after assessing the condition and accessibility of the vein.

Table 13.5 Choice of intravenous device

Device	Gauge	Advantages	Disadvantages	Use
Needle	21	Cheaper than winged infusion devices. Easy to use with large veins.	Rigid. Difficult to manipulate with smaller veins in less conventional sites. May cause more discomfort. Venous access only confirmed when sample tube attached.	In large, accessible veins in the antecubital fossa. When small quantities of blood are to be drawn.
Winged infusion device with safety feature	21	Flexible due to small needle shaft. Easy to manipulate and insert at any site. Increases the success rate of venepuncture and causes less discomfort ( Garza and Becan‐McBride [66]). Usually shows a ‘flashback’ of blood to indicate a successful venepuncture.	More expensive than steel needles. The 12–30 cm length of tubing on the device may be caught and dislodge the needle.	Veins in sites other than the antecubital fossa. When quantities of blood greater than 20 mL are required from any site.
Winged infusion device with safety feature	23	Flexible due to its small needle shaft. Easy to manipulate and insert at any site. Causes less discomfort than a needle. Smaller swg and therefore useful with fragile veins.	More expensive than steel needles, plus there can be damage to cells that can cause inaccurate measurements in certain blood samples, e.g. potassium.	Small veins in more painful sites, e.g. inner aspect of the wrist, especially if measurements are related to plasma and not cellular components.

swg, standard wire gauge.

Pharmacological support

It is important to remember that patients may fear venepuncture and in some cases suffer from needle phobia. The use of topical local anaesthetic cream may be beneficial for anxious patients or children (Weinstein and Hagle [252]). Further information can be found in Chapter c17: Vascular access devices: insertion and management.

Non‐pharmacological support

Patient anxiety about the procedure may result in vasoconstriction. The nurse's manner and approach will also have a direct bearing on the patient's experience (McCall and Tankersley [138]). Approaching the patient with a confident manner and giving an adequate explanation of the procedure may reduce anxiety. Careful preparation and an unhurried approach will help to relax the patient and this in turn will increase vasodilation (Dougherty [53]).

Specific patient preparation

There are various considerations in patient preparation for venepuncture:

Injury, disease or treatment (e.g. amputation, fracture or cerebrovascular accident) may prevent the use of a limb for venepuncture, thereby reducing the venous access. Use of a limb may be contraindicated because of an operation on one side of the body (e.g. mastectomy and axillary node dissection) as this can lead to impairment of lymphatic drainage, which can influence venous flow regardless of whether there is obvious lymphoedema (Berreth [12], McCall and Tankersley [138]).
The age and weight of the patient will also influence choice. Young children have short, fine veins and the elderly have prominent but fragile veins. Care must be taken with fragile veins and the largest vein should be chosen along with the smallest‐gauge device to reduce the amount of trauma to the vessel (Weinstein and Hagle [252]). Malnourished patients will often present with friable veins (Dougherty [53]).
If the patient is in shock or dehydrated, there will be poor superficial peripheral access. It may be necessary to take blood after the patient is rehydrated as this will promote venous filling and blood will be obtained more easily (Dougherty [53]).
Medications can influence the choice of vein in that patients on anticoagulants or steroids or those who are thrombocytopenic tend to have more fragile veins and will be at greater risk of bruising both during venepuncture and on removal of the needle. Therefore, choice may be limited by areas of bruising present or the inability to access the vessel without causing bruising (Dougherty [53]).
The temperature of the environment will influence venous dilation. If the patient is cold, no veins may be evident on first inspection. Application of heat – for example, in the form of a warm compress or soaking the arm in warm water – will increase the size and visibility of the veins, thus increasing the likelihood of a successful first attempt (Garza and Becan‐McBride [66]).
Venepuncture itself may cause the vein to collapse or go into a spasm. This will produce discomfort and a reduction in blood flow. Careful preparation and choice of vein will reduce the likelihood of this, and stroking the vein or applying heat will help to resolve it (Dougherty [53]).
Involving patients in the choice of vein, even if it is simply to choose the non‐dominant arm, can increase a feeling of control, which in turn helps to relieve anxiety (Weinstein and Hagle [252]).
The environment is also another important consideration. In the inpatient and outpatient settings, lighting, ventilation, privacy and position must be checked and optimized where possible. This will ensure that the patient and the operator are both comfortable. Having adequate lighting is also beneficial as it illuminates the procedure, ensuring the operator has a good view of the vein and equipment (Weinstein and Hagle [252]).

Procedure guideline 13.1

Venepuncture

Table 13.6 Prevention and resolution (Procedure guideline 13.1)

Problem	Cause	Prevention	Action
Pain	Use of vein in sensitive area (e.g. wrist)	Avoid using veins in sensitive areas wherever possible. Use local anaesthetic cream.	Complete the procedure as quickly as possible.
Anxiety	Previous trauma	Minimize the risk of a traumatic venepuncture. Use all methods available to ensure successful venepuncture.	Approach patient in a calm and confident manner. Listen to the patient's fears and explain what the procedure involves. Offer patient the opportunity to lie down. Suggest use of local anaesthetic cream (WHO [257]).
Anxiety	Fear of needles		All of the above and perhaps referral to a psychologist if fear is of phobic proportions.
Limited venous access	Repeated use of same veins Peripheral shutdown	Use alternative sites if possible. Ensure the room is not cold.	Do not attempt the procedure unless experienced.
	Dehydration	Ensure correct device and technique are used.	Put patient's arm in warm water. Apply glycerol trinitrate patch (as prescribed).
	Hardened veins (due to scarring and thrombosis)		May be necessary to rehydrate patient prior to venepuncture.
	Poor technique or poor choice of vein or device		Do not use these veins as venepuncture will be unsuccessful.
Needle inoculation of or contamination to practitioner	Unsafe practice Incorrect disposal of sharps	Maintain safe practice. Activate safety device. Ensure sharps are disposed of immediately and safely.	Follow accident procedure for sharps injury, for example make site bleed and apply a waterproof dressing. Report and document. An injection of hepatitis B immunoglobulin or triple therapy may be required.
Accidental blood spillage	Damaged/faulty equipment Reverse vacuum	Check equipment prior to use. Use vacuumed plastic blood collection system. Remove blood tube from plastic tube holder before removing needle.	Report within hospital and/or the Medicines and Healthcare products Regulatory Agency. Ensure blood is handled and transported correctly.
Missed vein	Inadequate anchoring Poor vein selection Wrong positioning Lack of concentration Poor lighting	Ensure that only properly trained staff perform venepuncture or that those who are training are supervised. Ensure the environment is well lit.	Repalpate, withdraw the needle slightly and realign it, providing the patient is not feeling discomfort. Ensure all learners are supervised. If the patient is feeling pain, then the needle should be removed immediately.
	Difficult venous access		Ask an experienced colleague to perform the procedure.
Spurt of blood on entry	Bevel tip of needle enters the vein before entire bevel is under the skin; usually occurs when the vein is very superficial		Reassure the patient. Wipe blood away on removal of needle.
Blood stops flowing	Through‐puncture: needle inserted too far	Correct angle.	Draw back the needle, but if bruising is evident remove the needle immediately and apply pressure.
	Contact with valves	Palpate to locate.	Withdraw the needle slightly to move the tip away from the valve.
	Venous spasm	Results from mechanical irritation and cannot be prevented.	Gently massage above the vein or apply heat.
	Vein collapse	Use veins with large lumens. Use a smaller device.	Release tourniquet, allow veins to refill and retighten tourniquet.
	Small vein	Avoid use of small veins wherever possible.	May require another venepuncture.
	Poor blood flow	Use veins with large lumens.	Apply heat above vein.