Venipuncture / Blood sampling / Intravenous Catheterization in Ferrets (Disease Investigation & Management - Treatment and Care)

Sites

• The main site used is the jugular vein. Either the right or the left jugular can be used. (B631.18.w18)
• For small samples, the lateral saphenous vein (just proximal to the hock on the lateral side) or the cephalic vein (on the dorsal surface of the front leg, as in cats and dogs) can be used. (B631.18.w18, P120.2006.w6, J29.13.w2)
  • The cephalic vein can be used for catheterisation. (B631.18.w18, P120.2006.w6)
  • The lateral saphenous vein can be used for catheterisation (P120.2006.w6) in a collapsed ferret. (B631.18.w18)
• An alternative blood sampling site is the anterior vena cava. (B631.18.w18, P120.2006.w6)
• The ventral tail artery can be used for blood sampling. (J29.6.w3)

Procedure

From the cephalic or lateral saphenous veins

• Clip and prepare the leg.
  • The vein can be visualised by wetting the fur with isopropyl alcohol, without clipping the leg. (J29.6.w3)
  • Shaving makes visualisation of the vein easier. (B602.2.w2, J29.13.w2)
• Sample as in cats or dogs.
• Cephalic vein:
  • Have the handler hold the ferret in ventral recumbency, with the ferret's body between the handler's body and forearm, and the foreleg on the same side held forward, the vein raised. With the other hand, the handler holds the ferret's head and neck pointing upwards. (J29.6.w3)
    • A quick-release tourniquet can be placed to raise the vein. (J15.24.w5, J29.6.w3); this may be easier than having an assistant raise the vein. (J15.24.w5)
  • Using a needle and 1 mL syringe, enter the vein. (J29.6.w3)
    • Use a 27- or 28-gauge needle on an insulin syringe. (B602.2.w2)
  • Draw back on the syringe until blood flow starts. Have the handler reduce pressure on the ferret's forearm, to encourage blood flow to the leg. (J29.6.w3)
    • If a tourniquet has been used, release the tourniquet at this time. (J29.6.w3)
  • Use gentle suction; this reduces the risk of collapsing the vein. (J29.6.w3)
• Lateral saphenous vein: 
  • Have the handler hold the ferret in lateral recumbency. (J29.6.w3)
  • Have the handler place pressure around the thigh. (J29.6.w3) or  place a quick-release tourniquet to raise the vein. (J15.24.w5)
  • Take the sample using 27- or 28-gauge needle on an insulin syringe; this reduces the risk of collapsing the vein. (B602.2.w2, J29.6.w3)

Intravenous catheterisation:

• Anaesthetise the ferret, unless it is very depressed/moribund. (B602.2.w2, P120.2006.w7)
• Choose the site: usually the cephalic or lateral saphenous veins are used. (B602.2.w2)
  • Placement of a jugular catheter is more difficult. (B602.2.w2) Ferrets are less tolerant of the heavy bandaging of the neck needed if a jugular catheter is placed. (J29.6.w3)
• Shave the hair over the vein. (B602.2.w2)
• Raise the vein. (B602.2.w2)
• Puncture the skin over the vein using a 20- to 22-gauge needle; take care not to puncture the underlying vein. (B602.2.w2, J15.24.w5, J29.6.w3, J29.13.w2, P120.2006.w6, P120.2006.w7) a scalpel blade can also be used for nicking the skin. (J15.24.w5)
• Insert a short (3/4 inch) 22- 24- to 26-gauge over-the-needle catheter (B602.2.w2, P120.2006.w6, P120.2006.w7)
  • Attach the catheter to a T-connector. (B602.2.w2, , P120.2006.w6, P120.2006.w7)
• Tape the catheter in place, and bandage (P120.2006.w6); use a soft padded bandage. (B602.2.w2)
  • It is easier to reach and bandage the cephalic vein than the lateral saphenous or jugular. (P120.2006.w7)
• Closely monitor that the fluid line does not become tangled. (B602.2.w2)
• Note: Ferrets generally do not chew a catheter. (B602.2.w2)
  • Ferrets may chew a catheter. (J29.6.w3, P120.2006.w7)
• Note: This can be used with an injection port for repeated chemotherapy injections. (B602.2.w2)

(B602.2.w2, B631.18.w18, J29.6.w3, P120.2006.w6)

From the ventral tail artery

• Place the ferret in a warm environment, or apply moist heat to the tail; this encourages vasodilatation and increases blood flow. (B602.2.w2)
• Restrain the ferret in dorsal recumbency (B602.2.w2, J29.6.w3), in a towel with the neck scruffed and the back legs pulled cranially. (J29.6.w3)
• Apply topical lidocaine/prilocaine cream (EMLA cream, Astra Pharmaceuticals, Wayne, PA, USA). (B602.2.w2)
  • Note: If the ferret shows reactions indicating pain, anaesthetise the ferret before proceeding. (J29.6.w3)
• Using a 22-gauge needle attached to a syringe (J29.6.w3); 21- or 20- gauge needle (B602.2.w2)
• Insert the needle along the midline of the ventral aspect of the tail, about 2-5 cm from the tail base. The needle should be directed at a shallow angle towards the body. (B602.2.w2, J29.6.w3)
• Gently pull back on the syringe plunger as the needle enters the groove on the underside of the tail vertebrae. (J29.6.w3)
  • The artery is about 2-3 mm deep. (B602.2.w2)
• Once blood appears in the needle hub, keep drawing back on the plunger slowly (B602.2.w2, J29.6.w3) while holding the needle still, avoiding taking the needle through the artery. (J29.6.w3)
  • This site can be used for collection of 1-5 mL blood. (B602.2.w2, J29.6.w3)
• Withdraw the needle and apply pressure to the site for two to three minutes. (B602.2.w2)

From the jugular vein in a tractable ferret

• Restrain the ferret in a similar manner to restraint of a cat for this procedure, in ventral recumbency with the front legs pulled downwards over the edge of the table and the head and neck extended firmly upwards. (J29.6.w3, P120.2006.w6)
  • OR The ferret can be restrained in a towel: the scruffed ferret is wrapped in the towel, with the front legs held backwards against the thorax. The assistant then holds the cranial part of the scruff, with the ferret in dorsal recumbency. (J29.6.w3)
  • OR A single-handed technique has been described: "Extend the ferret's neck with one hand by placing the index finger under the chin and the thumb across the thoracic outlet. Use the rest of the fingers to wrap around the back of the ferret's neck. Do not use any restraint on the body. Once the ferret is calm, access the vein." (J29.6.w3)
• If necessary, shave the hair over the ventral neck. (J29.6.w3, J29.13.w2)
• Wet the area with isopropyl alcohol.
• Raise the vein using thumb pressure just lateral to the thoracic inlet. (B631.18.w18, J29.6.w3)
• Visualise/palpate the jugular vein; this runs from the thoracic inlet to the base of the ear. (J29.6.w3)
  • Note: the vein is placed more laterally than in cats and dogs. (J29.13.w2)
  • Note: The jugular vein is quite shallow. Avoid probing too deeply. (J29.6.w3)
• Use a 25 gauge needle and a 1-3 mL syringe. (P120.2006.w6)
  • Use a 22- to 20-gauge needle, bent at a shallow angle. (J29.6.w3) 21-23 gauge needle, bent at a shallow angle (about 30 degrees). (J15.24.w5)
  • Use a 22 - 25 gauge needle attached to a 3 mL syringe. (J29.13.w2)
• Once the needle is in the vein, the head can be "pumped" slowly up and down to improve blood flow. (B602.2.w2)

From the jugular vein in an anaesthetised ferret

• Anaesthetise the ferret using isoflurane. (B631.18.w18)
• Use a 23 gauge or smaller needle. (B631.18.w18)
• Raise the vein using thumb pressure. (B631.18.w18)
• Consider making a small stab incision in the skin over the vein. Note: take great care not to incise the vein. (B631.18.w18)
• Insert the needle into the vein and take the sample. (B631.18.w18)

From the anterior vena cava

• Clip the left thoracic inlet area and prepare aseptically. (B631.18.w18)
• Anaesthetise the ferret. (B631.18.w18)
  • This procedure can be carried out in a calm unanaesthetised ferret with restraint by two nurses. (P120.2006.w6)
• Place the ferret in dorsal recumbency with the head resting over the edge of the table. (B631.18.w18)
• Have the front legs pulled caudally along the body. (B631.18.w18, J29.13.w2)
• Insert a 23 gauge, 1.25 inch needle (attached to a syringe) into the left thoracic inlet. (B631.18.w18)
  • Insert a 25 gauge needle (attached to a 1-3 mL syringe) "at a point just lateral to the manubrium at a 45-degree angle to the length of the body" (P120.2006.w6) "at a 45° angle into the notch between the manubrium and the first rib. (J29.13.w2)
• Aim the needle diagonally across the ferret towards the right hind leg. (B631.18.w18, P120.2006.w6)
• Apply gentle negative pressure on the syringe while advancing the needle, until blood is aspirated. (B631.18.w18, P120.2006.w6)
  • OR Insert the needle to the hub then aspirate while slowly backing the needle out of the ferret until blood appears. (J29.13.w2)
  • Note: If this procedure is being carried out in an unanaesthetised ferret and it struggles, completely withdraw the needle immediately and allow the ferret to sit up, to avoid lacerating the vein. (J29.13.w2, P120.2006.w6)
• As the needle is withdrawn, put digital pressure over the thoracic inlet; this will minimise haematoma formation. (B631.18.w18)

• In tractable ferrets, it may be possible to take blood samples from peripheral veins or the jugular vein without sedation. (P120.2006.w6)
• The peripheral veins (cephalic or lateral saphenous) are suitable for small blood samples, and (particularly the cepalic) for catheterisation. (P120.2006.w7)
• The jugular or anterior vena cava are suitable for larger blood samples. (B631.18.w18, P120.2006.w6)
  • Blood flow from the jugular may be slow, with resultant clotting of blood. (P120.2006.w7)
• Intravenous access (rather than subcutaneous) should be used when treating severe hypoglycaemia, for lengthy surgical procedures, and for chemotherapy. (P120.2006.w7)

• Up to 10% of blood volume can be taken. Usually less than 1.5 mL is needed for haematology and biochemistry. (P120.2006.w6)
  • In a 1 kg ferret, blood volume is about 100 mL. (J29.6.w3)
• To prevent clotting, for biochemical testing, a heparinised syringe can be used. (P120.2006.w7)

• The short legs make blood sampling from the cephalic veins relatively difficult. (B631.18.w18)
• There is more inherent risk if sampling from the vena cava than from other blood vessels. (J29.6.w3)
• Some blood parameters are altered by isoflurane anaesthesia (haematological parameters lowered, including WBC count, PCV and RBC count), with the maximum effect reached after 15 minutes of anaesthesia. It is important to tell the laboratory if anaesthesia has been used to collect the sample. (B602.2.w2, B631.18.w18, J29.6.w3)
  • Ensure all equipment is ready before anaesthetising a ferret for blood sampling, so that the sample can be taken as soon as possible once the ferret is anaesthetised, to minimise changes in electrolytes. (B631.18.w18)
• Anaesthesia may be required to place an intravenous catheter. (B631.18.w18)
• Ferrets tend to twist fluid lines and to chew catheters. Close monitoring is required if an intravenous catheter is in place. (P120.2006.w7)
  • If the ferret chews the catheter and swallows it, there is a risk of Gastro-intestinal Foreign Bodies in Rabbits and Ferrets. (J29.6.w3)
  • Long fluid lines help avoid catheter dislodgement when the ferret is moving around in its bedding. (J29.13.w2)
• Clipping a toe nail short should not be used for a small blood sample. It is painful for the ferret and if done repeatedly can cause malformation of the nail; the sample may also be mixed with other fluids. (B631.18.w18, J29.6.w3)

• For sampling from the cephalic vein or lateral saphenous vein: 25-28 gauge needle, 1 ml or insulin syringe. (P120.2006.w6)

• For sampling from the anterior vena cava: 25 gauge needle, 1-3 mL syringe. (P120.2006.w6)

• For sampling from the anterior vena cava: 23 gauge 1.25 inch needle. (B631.18.w18)

• 25-33 gauge needle. (J29.6.w3)

• Insulin syringe or tuberculin syringe to avoid excessive negative pressure which may collapse the vein. (J29.6.w3)

• This procedure should only be carried out by an individual with appropriate clinical training and practical experience.

• Not expensive unless expensive drugs are being administered. 
• Cost will be increased if anaesthesia is required.

Use of Drugs (Medication):

• Many drugs are not registered for use in ferrets and care should be taken in their use, with proper regard for possible toxic effects. Consideration should be give to relevant legislation regarding the use of drugs.
• In any country, drugs are unlikely to be specifically licensed for use in non-domestic mammals. 
  • In Europe the prescription cascade must be followed, and the client's informed consent should be obtained, whenever a drug is used which is not licensed for use in a given species. (B284.5.w5)
  • In the UK, guidelines regarding the use of drugs are set out in the Royal College of Veterinary Surgeons Guide to Professional Conduct 2000: (see: LCofC1 - RCVS Guide to Professional Conduct 2000 - Choice of Medicinal Products).