1. VENIPUNCTURE
Chapter 20, pages 585 – 590, in CTVT

2. OBJECTIVES
Describe patient preparation, positioning, and procedures for blood collection from peripheral veins
Describe indications and procedures for collection of arterial blood samples in small animals
Become familiar with blood collection techniques and protocols

3. General Principles for Collection Of Samples for Laboratory Testing
Blood and urine samples should be obtained before treatment
Supplies are appropriate for the sample and gathered before collection is started
Site of collection is free of disease and debris
Area is prepared properly
Technician should be proactive in recognizing potential problems.

4. Blood Sample Collection
General guidelines
Minimum stress to patient is required
Avoid hemolyzed sample
Fill vacuum tube with syringe
Anticoagulant tubes mixed gently
Serum tubes set at an angle and allowed to clot

5. Patient Condition Examples
Is the animal in Shock?
Dehydration status
Is the animal Breathing?
Is the animal Normal and Healthy?
Are all the veins blown?
Is the animal a neonate?

6. Temperament Examples Is the animal trying to take your head off?
Is the animal calm and laid back?
Is the animal conscious?
Is the animal dying?
Remember “flight or fight” syndrome?

7. Venipuncture Supplies
Needles (Get more than one)
Syringes (Get more than one)
Cotton balls (or gauze) in alcohol
Vet Wrap, gauze or dry cotton balls (Band-aid)
Muzzle or muzzles (E-collars can also act as great restraint devices)
Proficient person to restrain the animal
Hydrogen Peroxide (optional and if available)

8. Venous Blood Sample
Only through experience does one learn to collect a blood sample quickly with minimal trauma to the vessel and minimal stress and discomfort to the patient
Proper RESTRAINT is as important as the venipuncture technique
You must always insert the needle bevel facing up, into the vein
Unlike injections – you ‘hold off’ the ENTIRE time, until you obtain all the blood you need

9. Venous Blood Sample
Performed with a needle and syringe or a vacutainer collection system
The method and needle gauge depend on:
Vessel size
Amount of blood required
Intended use of the sample
technician preference
You should use the largest needle possible for the vein chosen and direct the bevel upward

11. Always think about the situation before you draw blood
Blood Collection
The reason you are drawing blood will dictate:
Limb to be used
Amount of blood you will need
Time frame involved
Your expertise
Always think about the situation before you draw blood

12. Simple Guidelines
Smaller gauge needles are used with smaller or more fragile vessels, or multiple venipunctures
The amount of negative pressure applied to aspirate the blood into the syringe must not be excessive
Forceful retraction of the plunger may result in hemolysis of the red blood cells as they pass through the needle. Remember these little guys are fragile. Not only can you collapse the vein but your lab results may be effected

13. Guidelines
Before venipuncture, the hair and skin over the vessel are wiped with a cotton ball saturated with 70% isopropyl alcohol (or you can shave the hair)
This helps to remove dirt, causes vasodilation, and improves visualization of the vein
In animals with dense hair coats, the vessel may be easier to identify if the hair over the vessel if parted with an alcohol ball or shaved

14. Peripheral Vein Blood Collection
Introduce the needle into the occluded vessel as far distally as possible.
Use a quick but smooth “poke”
Do not “jab” into the vein – you will go through it
If your first attempt is unsuccessful reinsert the needle more proximal to the previous entry site. In other words, make your first attempt to draw blood as far down the leg as possible. If you miss or damage the vein you can always make other attempts moving upward along leg

16. Cephalic Venipuncture
The cephalic vein is located on the cranial aspect of the foreleg
The animal is restrained in sternal recumbency or in a standing position. Your larger breed dogs prefer to remain standing or be seated with the foreleg in extension
If you are utilizing the right cephalic vein the restrainer is positioned on the animal’s left side
Use your thumb to help stabilize the vein so it does not roll

18. Lateral Saphenous Vein

20. Medial Saphenous Venipuncture in the Cat
This vein is located on the medial aspect of the rear leg, and is used to obtain small volumes of blood, primarily in felines
If the right vein is used place the cat in right lateral recumbency with the left rear leg abducted
The vein is occluded with pressure applied by the restrainer’s left hand in the right marginal region (kitty karate chop)
Wipe the leg with alcohol and part the fur until you see the vein
Blood is collected with a 22- to 25- gauge needle attached to a 1- or 3-ml syringe

21. Medial Saphenous Venipuncture in the Cat
Firm pressure is applied to the puncture site for at least 60 seconds after venipuncture. It is extremely important to do this because the medial saphenous veins are especially prone to hematoma formation
Even the best phlebotomist can cause a hematoma on a cat

22. Medial Saphenous Vein

24. Jugular Venipuncture Collection
Patient's head is raised exposing the neck
Your initial attempt should be made in the caudal third of the jugular vein
Subsequent attempts can be made in a more cranial region
If the vessel is damaged in the distal portion of the vein, a more proximal region is still patent and usable for blood collection
The jugular furrow can be palpated just lateral to the trachea
Person drawing the blood must “Hold Off”

27. Palpation of the jugular vein in lieu of visualization may be necessary in some animals
Wiping the neck with alcohol helps to visualize the vein. In cats, water is sometimes used because the smell of alcohol is often repugnant to them. The smell sometimes makes them gag

32. After the Blood Collection; With a sense of urgency!
Detach needle from your syringe
Remove stopper from collection tube
Transfer blood into the tube
If utilizing a anticoagulant tube, gently
invert the tube a few times to mix the
contents. Do NOT SHAKE it!
Your tube must be filled at least half way to
achieve the appropriate blood/anticoagulant ratio
Always dispose of your needles/syringes in the “sharps” container

33. Marginal Ear Vein – At Home Glucose testing

34. Arterial Blood Sampling
WHY?
Best way to assess pulmonary function
Blood Gasses tell us about the patient’s ability to ventilate and oxygenate
WHAT?
Measure CO2 (ventilation) and O2 (oxygenation)
Performed on a Blood Gas analyzer

36. Common errors with blood collection and handling
Rapid or forceful aspiration of the blood, especially through a needle less than 22g
Traumatic aspiration of blood
Spraying the blood through the needle into a second vial. The needle and tube stopper should be removed and the blood runs gently down the inside of the vial
Water present in the syringe, needle, or tube, causing osmotic damage to the cells
Collecting too little or to much blood for the amount of anticoagulant present, resulting in dilution error or direct cellular damage from concentration anticoagulant
Slow collection or delayed transfer to anticoagulant, allowing clumping of platelets and clot formation
Improper or incomplete mixing of anticoagulant. The tube should be gently but thoroughly rotated by hand or on an automatic tube rotator or it may be rolled across a flat surface
Excessive physical force, such as shaking, jarring, or dropping

37. VIDEOS ON VENIPUNCTURE
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