Blood collection

Islamic University – Gaza (IUG)

Islamic University – Gaza (IUG)

IntroductionHematology: Is defined as the study of

blood.

Everybody is familiar with the sight of blood - the red fluid that oozes out of your body when you've sustained a cut or a deep injury, which is slightly denser and approximately 3-4 times more viscous than water.

Blood Volume-:

Blood volume is variable, but tend to be about 5- 6 liters , or 7- 8 % of the body weight. Factors such as body size, amount of adipose tissue, and electrolyte concentrations all affect volume .

Blood Composition-:Approximately 45% of the blood is composed of formed elements: red blood cells , white blood cells , and platelets. The remaining 55% of the blood is fluid portion, of which approximately 90% is water and 10% is composed of proteins, carbohydrates, vitamins, hormones, enzymes, lipids, and salts

The components of blood can be separated by filtration, however, the most common method of separating blood is to centrifuge (spin) it.Three layers are visible in centrifuged blood. The straw-colored liquid portion, called plasma, forms at the top (~55%). A thin cream-colored layer, called the Buffy coat, forms below the plasma.The Buffy coat consists of white blood cells and platelets. The red blood cells form the heavy bottom portion of the separated mixture (~45%).

Note-:

Venipuncture (Phlebotomy)

• The process of obtaining intravenous access.

• There are three veins most commonly used in venipuncture, or phlebotomy:

The cephalic The median cubital The basilic veins

• These three veins are found in the antecubital area. • The cephalic vein is found on the lateral, or outside, of the arm.

• The median cubital vein, the preferred one to use, is found close to the center.

• The basilic vein is located on the inner, or medial part of the antecubital area.

Common Sites for Venipuncture

The median cubital vein is the preferred vein for phlebotomy because:

It is usually larger than the other veins. Best anchored vein (More stationary(.

• Veins can move, or roll, which makes it more difficult to perform phlebotomy. The median cubital is typically well anchored, which makes it less likely that the patient will feel pain during phlebotomy, or bruise afterwards.

Median Cubital – First Choice

• This vein is located in the antecubital fossa. (the area of the arm in front of the elbow)

• Well anchored vein, usually large and prominent.

• Very few problems. Offering the best chance for a close to painless puncture, as there are few nerve endings close to this vein.

Cephalic Vein – Second Choice

• Cephalic vein which is located on the lateral side of the arm.

• This vein is usually well anchored.

• The cephalic vein may lie close to the surface.

Basilic Vein – Third Choice

• Located on the medial side of the arm. • In many patients this vein may not be well

anchored and will roll, making it difficult to access with the needle.

• Additionally, this area is often more sensitive, thus a stick is slightly more painful for the patient

• The cephalic and basilic veins are only used if the medial cubital vein is not felt.

• The cephalic vein is the second choice usually, since it is fairly well anchored. This is often the only vein that can be felt in patients who are obese.

• The basilic vein is kept as a last choice option. It rolls more easily and runs directly over a nerve and an artery, making it a more dangerous and painful area to use.

Hand Veins

• At times, none of the veins of the antecubital fossa will be felt or not be able to be used due to intravenous placement or injury, hand veins may be used.

• Veins of the hand and wrist are usually close to the surface, but they are prone to movement and rolling.

• Using these veins tends to be more painful for the patient, since there are nerves running through the hand as well.

• If using these veins, it is important to anchor the vein with your hand, holding it in place, when you are drawing the blood.

Venipuncture, why ?

• Intravenous therapy

• Venous blood sample

• Parenteral nutrition

Anticoagulants• Most hematology and coagulation procedures must be

performed on whole blood or plasma. There for, as soon as the blood is withdrawn from the patient, it is mixed with an anticoagulant to prevent coagulation. The three most commonly used anticoagulants in the hematology laboratory are discussed below:

1- EDTA:• Is generally available as the sodium, dipotassium or

tripotassium salt of ethylene diamine tetra acetic acid. It is used in concentration of 1.5(±.25).

• EDTA prevents coagulation by binding the calcium in the blood (calcium is required for blood coagulation).

Excessive concentration of EDTA cause:

• Shrinkage of the red blood cells leading to decreased hematocrit, increased MCHC, falsely low ESR.

• Degenerative changes in the white cells and the platelets will swill and break up causing a falsely increased in platelet counts.

2- Sodium citrate: • Is used for coagulation studies in a concentration of 1

part 0.109M sodium citrate (tri sodium citrate dehydrate) to9 part whole blood.

• Sodium citrate prevents coagulation by binding the calcium of the blood in a soluble complex.

3 -Heparin:• May be used in concentration of 15 to 30 units/ml of

whole blood. its may cause clumping of platelets and white cells.

• Coagulation is prevented by interaction with anti thrombin III and subsequent inhibition of thrombin.

Equipments(Instruments)

Blood Collection tubes

• glass or plastic tube with a rubber stopper.

• It has a vacuum so that blood will flow into the tube.

• anticoagulants and/or other chemical additives.

Blood collection tubes

• Rubber stoppers of blood collection tubes are color coded.

• Each type of stopper indicates a different additive or a different tube type.

Blood collection tubes: Safety

• The rubber stopper is positioned inside the plastic shield

Syringes

Needles

Needles

• Different sizes.

• size =gauge.

• The larger the needle, the smaller the gauge number.

• 21 or 22 gauge needle is mostly used.

Needle Components

Single Draw Needle

• Single draw needles are of the type that fit on a syringe, and can be used only to fill the syringe to which they are connected.

Butterfly Needle

• Winged infusion set• Difficult venipunctures

including pediatric draws

• with a syringe or a holder and vacuum collection tube system.

• 21, 23, or 25 gauge.

Lancets

• Lancets are used for difficult venipunctures, including pediatric draws.

Tourniquets

• Vein easier to SEE, FEEL and PUNCTURE

Sterilization

Bandaging Material

Gloves

• Gloves must be worn for all procedures requiring vascular access.

• Non-powdered latex gloves are most commonly used;

Sharp Disposal Container

Collecting Blood

Greeting

• Always greet patient in a professional, friendly manner.

• A good initial impression will earn the patients trust, and make it easier and more pleasant to draw a good specimen.

• Identify yourself by name and department.

• Explain the reason for your presence.

• The more relaxed and trusting your patient, the greater chance of a successful non traumatic venipuncture.

• Good verbal, listening, and nonverbal skills are very important for patient reassurance

Technical Tip

Patient Identification

• Make sure the name, medical record number, and date of birth on your order/requisition match those on the patient’s armband.

• Verify the patient’s identity by politely asking them to state their full name.

• Properly identifying patients and specimens is probably the single most critical part of your job.

• The consequences of misidentifying a specimen can be life threatening.

• Never rely on the patient name on the door or above the bed. Patients are frequently moved from room to room.

• A hospitalized patient must always be correctly identified by an ID band that is attached to the patient.

Technical Tip

Standard Precautions

Wash hands

Apply gloves

• Patients are often reassured that proper safety measures are being followed when gloves are put on in their presence.

Technical Tip

Position the Patient

• Comfortable position

• Turn the arm so that the wrist and palm face upward, and the antecubital area is accessible

• When supporting the patient’s arm, do not hyperextend the elbow. This may make vein palpation difficult.

Technical Tip

Applying the tourniquet

• Tie the tourniquet just above the elbow.

• The tourniquet should be applied a maximum of 1 – 2 minutes.

Applying the tourniquet

Applying the tourniquet

• After applying the tourniquet, you may ask the patient to make a fist to further distend the arm veins.

• Patients often think they are helping by pumping their fists

• This is an acceptable practice when donating blood, but not in sample collection as this can lead to hemoconcentration

Technical Tip

Choose a site

• The median cubital vein

• If not accessible: Cephalic vein, or the Basilic vein.

• If not accessible: veins on the back of the hand.

• Use a much smaller needle for these hand veins.

• Scarred, abraded, or inflamed skin

• Arms containing IV catheters

• Edematous arms

• Occluded Veins

• Shunts

Never draw from these areas

Cleansing the site

• Isopropyl alcohol swab

• Outward expanding spiral starting with the actual venipuncture site.

• Allow the alcohol to dry:-

• 1-disinfect the site

• 2-prevent a burning sensation

• Patients are quick to complain about a painful venipuncture. The stinging sensation caused by undry alcohol is a frequent, yet easily avoided, cause of complaints.

Technical Tip

Hold vein in place

Insert needle

the needle bevel up

Push tube into holder

• Gently push the tube onto the needle holder so that the catheter inside the needle holder penetrates the tube.

• Blood flow should be visible at this point.

• Allow tubes to fill until the vacuum is exhausted to ensure the correct blood to anticoagulant ratio.

Technical Tip

Removing the Needle

• Gently release the tourniquet before the last tube of blood is filled

• Remove the last tube from the needle

• Withdraw the needle in a single quick movement

Apply Pressure

• Quickly place clean gauze over the site, and apply pressure.

• You may ask the patient to continue applying pressure until bleeding stops.

Apply Adhesive bandage

• The practice of quickly applying tape over the gauze without checking the puncture site frequently produces a hematoma

Technical Tip

Needle disposal

• Remove the needle from the holder if appropriate, and properly discard it in an approved sharps disposal container.

• Discard all waste and gloves in the appropriate biohazardous waste container.

• Wash hands.

Specimen Labeling

• Label specimens at the bedside according to your institution’s standard procedures, or apply preprinted labels.

• Proper labeling is the single most critical task you are asked to perform.

Proper labeling generally includes:

• Patient’s first and last name

• Hospital identification number

• Date & time

• Phlebotomist initials

• Your institution may provide bar coded computer generated labels that contain this information.

• Patient identification • Filling out the requisition

• Equipment

• Apply tourniquet and palpate for vein

• Sterilize the site

• Insert needle

• Drawing the specimen

• Releasing the tourniquet

• Applying pressure over the vein

• Applying bandage

• Disposing needle into sharps

• labeling the specimens

REVIEW OF VENIPUNCTURE PROCEDURE

Perform VenipuncturePerform Venipuncture

TROUBLESHOOTING

Blood won’t flow

• If you do not see blood flow, the tip of the needle:

• May not yet be within the vein.

• May have already passed through the vein.

• May have missed the vein entirely.

• May be pushed up against the inside wall of the vein.

Incomplete collection or no blood is obtained:

• Change the position of the needle. Move it forward (it may not be in the lumen)

• or move it backward (it may have penetrated too far).

• Adjust the angle (the bevel may be against the vein wall).

• Try another tube. There may be no vacuum in the one being used.

• Re-anchor the vein. Veins sometimes roll away from the point of the needle and puncture site.

Other Problems

• A hematoma forms under the skin adjacent to the puncture site - release the tourniquet immediately and withdraw the needle. Apply firm pressure.

• The blood is bright red (arterial) rather than venous. Apply firm pressure for more than 5 minutes

Capillary PunctureCapillary Puncture

• Safe

• Quick

• Small amount of blood

• Increased use

• Safe

• Quick

• Small amount of blood

• Increased use

Capillary Puncture SitesCapillary Puncture Sites

•Fingertip

•Great toe

•Heel

•Fingertip

•Great toe

•Heel

• Fingertip

• Great toe

• Heel

• Fingertip

• Great toe

• Heel

LancetsLancets

• Sterile

• Single-use

• Different lengths

• Sterile

• Single-use

• Different lengths

Finger stick-Specimen collection

• A safety Lancet, which controls the depth of incision

Finger stick

• If possible, use the fourth (ring) finger or the middle finger.

• Many patients prefer that you use fingers on their nondominant hand.

• Choose a puncture site near the right or left edge of the finger tip.

• Clean the site as you would for routine venipuncture.

Finger stick

• Select a safety lancet appropriate for the size of the patient’s finger.

• You may warm the finger prior to puncture to increase blood flow.

• Make the puncture perpendicular, rather than parallel, to the finger print.

Finger stick

• Wipe away the first drop of blood using gauze to remove tissue fluid contamination.

Finger stick

• Collect blood into an appropriate tube.

• Label specimens appropriately.

• Make sure bleeding has stopped. Apply an adhesive bandage if necessary.

• Discard sharps appropriately.

• Peform finger or heel puncture across the fingerprints as the blood will more likely bead rather than run down the "channels" of the fingerprints.

Heel stick

• Veins of small children and infants are too small for venipuncture;

• Butterfly needles may be used to collect venous blood in older children.

Heel stick

• Firmly grasp the infants foot.• Do not use a tourniquet.• The heel may be warmed with

a cloth to help increase blood flow.

• Wipe the collection site with an alcohol prep pad, and allow the alcohol to dry.

• Wipe the site with sterile cotton or gauze, to be sure all the alcohol has been removed.

Heel stick

• Puncture the left or right side of the heel, not the bottom of the foot.

• Wipe away the first drop of blood since it may contain excess tissue fluid or alcohol which could alter test results.

Heel stick

• Collect the blood into the appropriate tube.

Heel stick

• After collection is completed, apply pressure to the puncture site with a sterile gauze pad until bleeding has stopped.

• Do not apply an adhesive bandage to an infant’s foot since it may injure its delicate skin.

Heel stick

Fainting

• Rarely, patients will faint during venipuncture.  

• It is therefore important that patients are properly seated or lying in such a way during venipuncture so that if they do faint, they won’t hurt themselves.

• self-limited

Fainting; what to do?• Gently remove the tourniquet and needle

from the patients arm, apply gauze and pressure to the skin puncture site. 

• Call for help. 

• If the patient is seated, place him on his back, with his hips flexed to help blood return to the brain. 

• A cold compress on the back of the neck may help to revive the patient more quickly.