Blood Sampling Flashcards
What do you do before you begin blood sampling?
Collect all the equipment needed for the procedure and place it within safe and easy reach on a tray or trolley, ensuring that all the items are clearly visible
Name the blood sampling equipment required?
- asterileglass or bleeding pack (collapsible) if large quantities of blood are to be collected
- well-fitting, non-sterilegloves
- an assortment of blood-sampling devices (safety-engineered devices or needles and syringes)
- a tourniquet
- alcohol hand rub
- 70% alcohol swabs for skindisinfection
- gauze or cotton-wool ball to be applied over puncture site
- laboratory specimen labels
- laboratory forms
How do you identify and prepare the patient?
- Introduce yourself to the patient, and ask the patient to state their full name
- Check that the laboratory form matches the patient’s identity (i.e. match the patient’s details with the laboratory form, to ensure accurate identification).
- Ask whether the patent has allergies, phobias or has ever fainted during previous injections or blood draws.
- If the patient is anxious or afraid, reassure the person and ask what would make them more comfortable.
- Make the patient comfortable in a supine position (if possible).
- Place a clean paper or towel under the patient’s arm
How do you select the site for venepuncture?
- Extend the patient’s arm and inspect the antecubital fossa or forearm.
- Locate a vein of a good size that is visible, straight and clear
- DO NOT insert the needle where veins are diverting, because this increases the chance of a haematoma.
- The vein should be visible without applying the tourniquet
- Locating the vein will help in determining the correct size of needle
The best site and vein for venpuncture is?
the antecubital fossa/forearm and the median cubital vein
- it lies between muscles and is usually the most easy to puncture
Note: Under the basilic vein runs with an artery and a nerve, so puncturing here runs the risk of damaging the nerve or artery and is usually more painful.
Where do you apply the tourniquet?
Apply the tourniquet about 4–5 finger widths above the venepuncture site and re-examine the vein
How to perform hand hygiene and put on gloves?
- wash hands with soap and water, and dry with single-use towels; or
- if hands are not visibly contaminated, clean with alcohol rub – use 3 ml of alcohol rub on the palm of the hand, and rub it into fingertips, back of hands and all over the hands until dry.
- After performinghand hygiene, put on well-fitting, non-sterilegloves
How to disinfect the entry site?
- clean the site with a 70% alcohol swab for 30 seconds and allow to dry completely (30 seconds)
- Apply firm but gentle pressure.
- Start from the centre of the venepuncture site and work downward and outwards to cover an area of 2 cm or more. - Allow the area to dry
- Failure to allow enough contact time increases the risk of contamination. - DO NOT touch the cleaned site
in particular, DO NOT place a finger over the vein to guide the shaft of the exposed needle
Note: If the site is touched, repeat thedisinfection.
Why do we use alcohol to disinfect the entry site?
alcohol is preferable to povidone iodine, because blood contaminated with povidone iodine may falsely increase levels of potassium, phosphorus or uric acid in laboratory test results
Why is the alcohol used for disinfection of a low percentage?
so as to not discolour the skin
How do you take blood?
- Anchor the vein by holding the patient’s arm and placing a thumb BELOW the venepuncture site.
- Ask the patient to form a fist so the veins are more prominent.
- Enter the vein swiftly at a 30 degree angle or less, and continue to introduce the needle along the vein at the easiest angle of entry.
- Once sufficient blood has been collected, release the tourniquet BEFORE withdrawing the needle.
How do you withdraw the needle?
- Withdraw the needle gently and apply gentle pressure to the site with a clean gauze or dry cotton-wool ball.
- Ask the patient to hold the gauze or cotton wool in place, with the arm extended and raised.
- Ask the patient NOT to bend the arm, because doing so causes a haematoma.
When do you remove the tourniquet?
Some guidelines suggest removing the tourniquet as soon as blood flow is established, and always before it has been in place for two minutes or more.
What do you do when obtaining multiple tubes of blood?
use evacuated tubes with a needle and tube holder.
This system allows the tubes to be filled directly
Note: If this system is not available, use a syringe or winged needle set instead.
How to use a syringe or winged needle set?
- best practice is to place the tube into a rack before filling the tube.
- To prevent needle-sticks, use one hand to fill the tube or use a needle shield between the needle and the hand holding the tube. - Pierce the stopper on the tube with the needle directly above the tube using slow, steady pressure.
- Do not press the syringe plunger because additional pressure increases the risk of haemolysis. - Where possible, keep the tubes in a rack and move the rack towards you
- Inject downwards into the appropriate coloured stopper.
- DO NOT remove the stopper because it will release the vacuum
