Venipuncture in Ferrets
Restraining the patient is probably the biggest challenge of venipuncture in ferrets. Restraint is usually not a problem in very sick ferrets, but most ferrets that need a presurgical assessment are still active and alert. There are two means of stabilization: good assistants and anesthetics. The best way to hold a ferret depends on the site of venipuncture.
Related Article: Venipuncture in Small Exotic Companion Mammals
In lateral recumbency (Figure 1), which is typically used for blood collection from the saphenous vein, ferrets can be held by the scruff and stretched by the assistant.
In sternal recumbency (Figure 2), which is used for both cephalic and jugular blood collection, the ferret can be held with the front part of the body extending off the end of the table. The assistant holds the head up by gently but firmly placing a grip around the neck just under the mandible and wraps a towel around the body and rear legs to stabilize the ferret. The assistant also holds the front legs as the ferret's body, which is wrapped in the towel, is stabilized between the assistant's arm and body.
In dorsal recumbency (Figure 3), another position used for jugular collection, the assistant stretches the ferret by holding the rear legs near the hips and bringing the front legs down across the body. Another assistant or the phlebotomist holds the head.
In a busy practice, it may not be possible to get an assistant to help with blood collection, or a willful ferret may make it impossible even if able assistants are available. The safest, easiest, and fastest method of tranquilization for blood collection in ferrets is the use of a gas anesthetic, such as isoflurane. The ferret's head is placed in a face mask, and isoflurane is administered. In a few minutes, the ferret is calm enough for venipuncture without the aid of an assistant.
Procedural Pearl: Ferret skin is tough; use a new, sharp needle if several venipuncture attempts have failed.
What You Need
25-gauge, 5/8-inch needle attached to a 1- or 3-cc syringe OR
an insulin syringe and small-gauge needle
At least one able assistant
Occasionally isoflurane anesthesia to tranquilize ferrets
Blood is primarily collected from ferrets through the lateral saphenous vein, the jugular vein, and the vena cava. The cephalic vein is used less frequently in ferrets because the lateral saphenous vein is larger and more easily accessible.
Both the lateral saphenous and cephalic veins are used when only small amounts of blood are needed. Insulin syringes are used in these vessels, and typically no more than 0.3 ml is taken. Conversely, the jugular vein or vena cava is used when a larger volume of bloodis required.
The vena cava should be reserved for the experienced ferret practitioner.
Related Article: Adrenal Gland Disease in Ferrets
Lateral Saphenous VeinThe saphenous vein is found toward the distal aspect of the leg and may appear torturous.
To obtain blood from the lateral saphenous vein, hold the ferret in lateral recumbency, and hold off the vein in the hindlimb just above the stifle joint.
Cephalic VeinThe cephalic vein is found midline on the foreleg, and the ferret is usually held in sternal recumbency for collection from this site. The vessel is small and collapses easily.
Hold off the vein as shown.
Jugular VeinFor jugular venipuncture, use a 25-gauge needle on a 1- or 3-ml syringe. However, it is easy to collapse the jugular vein using a 3-ml syringe, and this may increase the time for blood collection, leading to clotting and hemolysis of the sample.
Procedural Pearl: A 3-ml syringe often causes collapse of the jugular vein. Use a 1-ml syringe.
The site of jugular venipuncture is shown above. The ferret's head is beneath the towel at the top of the figure, and its legs are extended out to each side.
Procedural Pearl: It is easier to palpate the jugular vein than to see it.
The jugular vein is accessed by holding the ferret in sternal or dorsal recumbency. With both positions, the jugular vein may barely be visualized on the more lateral aspect of the neck. It is easier to palpate the jugular vein than to actually see it.
Vena CavaIn venipuncture of the vena cava, the ferret is held completely still and as straight as possible in dorsal recumbency. Tranquilization or two assistants may be necessary to accomplish this.
Usually, a 25-gauge, 5/8-inch needle attached to a 1- or 3-ml syringe is inserted into the skin at the notch formed by the manubrium and first rib either on the left or right side. Place the syringe at a 45-degree angle to the body, and insert it up to the hub. Then slowly pull the plunger back until blood fills the syringe. Because this is a blind stick, the syringe may also need to be pulled back slowly until it fills with blood. Blind sticking can be a dangerous procedure because of the risk for perforation of the numerous important structures that course through the area, and ferrets with undiagnosed thoracic disease may not tolerate this type of handling. The advantage to this method is the ease with which large samples of blood can be quickly obtained.
Procedural Pearl: Caution: venipuncture of the vena cava is not recommended for those who are inexperienced with ferrets.