cmecde 569

 

• The bottles appropriate for the tests that you are sending for (these vary from hospital to

hospital, but are generally yellow for biochemistry/U&Es, purple for haematology, pink for

group and save and crossmatch, blue for clotting/coagulation, grey for glucose, and black

for ESR)

• Cotton wool, swab, or gauze

• Tape or plaster

Make sure you have a yellow sharps box close at hand. The key to passing this station is

to be seen to be safe.

The procedure

• Wash your hands (see Station 1).

• Position the patient so that his arm is fully extended. Ensure that he is comfortable.

• Apply the tourniquet proximal to the venepuncture site.

• Select a vein by palpation: the bigger and straighter the better. The vein selected is most commonly the median cubital vein in the antecubital fossa.

• Don a pair of non-sterile gloves.

• Clean the venepuncture site with an alcohol steret. Explain that this may feel a little cold.

• Once the alcohol has dried off, attach the needle to the Vacutainer holder.

• Tell the patient to expect a ‘sharp scratch’.

• Retract the skin to stabilise the vein and insert the needle into the vein at an angle of 30–45

degrees to the skin.

Clinical Skills for OSCEs

6 Station 3 Venepuncture/phlebotomy

• Keeping the needle still, place a Vacutainer tube on the holder and let it fill.

• Once all the necessary tubes are filled, release the tourniquet. Remember that the tubes need

to be filled in a certain order (bottles with no additives first). See the guide to Vacutainer tubes

in Station 111.

• Remove the needle from the vein and apply pressure on the puncture site for at least 30

seconds (the patient may assist with this, or you may use tape or plaster).

• Immediately dispose of the needle in the sharps box.

• Remove and dispose of the gloves in the clinical waste bin.

Ensure that you release the tourniquet before removing the needle, and that you

immediately dispose of the needle in the sharps box.

After the procedure

• Ensure that the patient is comfortable.

• Thank the patient.

• Label the tubes (at least: patient’s name, date of birth, and hospital number; date and time of

blood collection).

• Fill in the blood request form (at least: patient’s name, date of birth, and hospital number; date

of blood collection; tests required).

• Document the blood tests that have been requested in the patient’s notes.

Examiner’s questions

If the veins are not apparent

• Lower the arm over the bedside.

• Ask the patient to exercise his arm by repeatedly clenching his fist.

• Gently tap the venepuncture site with two fingers.

• Apply a warm compress to the venepuncture site.

• Do not cause undue pain to the patient by trying over and over again (more than 2–3 times) –

call a more experienced colleague instead.

• Use femoral stab only as a last resort (usually in CPR situations).

In the event of a needlestick injury

• Encourage bleeding, wash with soap and running water.

• Immediately report the injury to your supervisor or the occupational health service.

• If there is a significant risk of HIV, post-exposure prophylaxis should be started as soon as

possible.

• Fill out an incident form.

For more information on the management of needlestick injury, refer to local or national protocols.

7General skills

Station 4

Cannulation and setting up a drip

Specifications: The station is likely to require you either to cannulate an anatomical arm and to put

up a drip, or simply to cannulate the anatomical arm. This chapter covers both scenarios.

Before starting

• Introduce yourself to the patient.

• Confirm his name and date of birth.

• Explain the procedure and obtain his consent. For example, “I would like to insert a thin plastic

tube into one of the veins on your arm. The tube will enable you to receive intravenous fluids and

prevent you from becoming dehydrated. You may feel a sharp scratch when the needle is inserted,

but only the plastic tube will remain in the vein. Do you have any questions?”

• Ask him on which arm he would prefer to have the cannula.

• Ask him to expose this arm.

• Gather the equipment in a clean tray.

It is important to read the instructions for the station carefully. If, for example, the

instructions specify that the patient is under general anaesthesia, you are probably not

going to gain any marks for explaining the procedure.

Cannulation only

The equipment

In a clean tray, gather:

• A pair of non-sterile gloves

• A tourniquet

• Alcohol sterets or prepackaged chlorhexidine and alcohol sponge

• An IV cannula of appropriate size (Table 1). Size is primarily determined by the viscosity of

the fluid to be infused (e.g. blood requires pink or larger) and the required rate of infusion

• A pre-filled 5 ml syringe containing saline flush

• An adhesive plaster/transparent film dressing

• A sharps box

The procedure

• Wash your hands (see Station 1).

• Position the patient so that his arm is fully extended. Ensure that he is comfortable.

• Apply the tourniquet proximal to the venepuncture site.

• Select a vein by palpation: the bigger and straighter the better. Try to avoid the dorsum of the

hand and the antecubital fossa if possible (may be uncomfortable on flexion).

• Don a pair of non-sterile gloves.

• Clean the skin with an alcohol steret and let it dry.

• Remove the cannula from its packaging and remove its needle cap.

• Tell the patient to expect a ‘sharp scratch’.

• Anchor the vein by stretching the skin and insert the cannula at an angle of approximately 30

degrees.

• Once a flashback is seen, advance the whole cannula and needle by about 2 mm.

Clinical Skills for OSCEs

8 Station 4 Cannulation and setting up a drip

• Pull back slightly on the needle and continue to hold the needle while advancing only the

cannula into the vein.

• Release the tourniquet.

• Occlude the vein by pressing on the vein over the tip of the cannula.

• Remove the needle completely, and immediately put it into the sharps box.

• Cap the cannula with the same cap that was on the end of the needle.

• Apply the adhesive plaster or transparent film dressing to secure the cannula.

• Flush the cannula with 5 ml normal saline to prevent blood from occluding it.

Table 1. IV cannulae

Colour Size Water flow (ml/min)*

Blue

Pink (most common)

Green

Grey

Orange

22G

20G

18G

16G

14G

33

54

80

180

270

* Approximate values. According to Poiseuille’s Law, the velocity of a

Newtonian fluid through a cylindrical tube is directly proportional to the

fourth power of its radius.

After the procedure

• Dispose of clinical waste in a clinical waste bin.

• Ensure that the patient is comfortable and inform him of possible complications (e.g. pain,

erythema).

• Thank the patient.

Setting up a drip

The equipment

In a clean tray, gather:

• A pair of gloves • An adhesive plaster

• A tourniquet • A sharps box

• Alcohol sterets • An appropriate fluid bag

• An IV cannula of appropriate size • A giving set

The procedure

• Check the fluid prescription chart (if appropriate).

• Check the fluid in the bag (solution type and concentration) and its expiry date.

• Remove the fluid bag from its packaging and hang it up on a drip stand.

• Remove the giving set from its packaging. The regulating clamp for the IV line should be closed.

• Remove the protective covering from the exit port at the bottom end of the fluid bag.

• Remove the plastic cover from the large, pointed end of the giving set.

• Drive the large, pointed end of the giving set into the exit port at the bottom end of the fluid

bag.