• Technique
• Summary
• Resources and references
• Blood vessel cannulation technique in other animals
• All blood sampling techniques in the guinea pig

Please read the general principles of blood sampling and catheterisation pages before attempting any cannulation procedure.

Technique

Blood vessel cannulation should be considered when repeated samples are required, as it avoids multiple needle entries at any one site. It is suitable for use in all strains of guinea pig and can be used to take blood from the femoral artery and vein, carotid artery, jugular vein, vena cava and dorsal aorta. Surgery is required and appropriate anaesthesia and analgesia should be used to minimise any pain caused. Proper aseptic technique should be used to prevent post operative infection.  Guinea pigs should be allowed to regain their pre-operative body weight before blood samples are taken. See this technique below.

The cannula is exteriorised at the nape of the neck (through a jacket and tether system). The jacket can cause swelling and skin abrasion and guinea pigs require regular and detailed observation to identify any problems. The use of a subcutaneous access port may be more appropriate because they eliminate the need for tethering systems during periods when animals are not being sampled from.

The jacket and tether system can restrict free movement and the guinea pigs may need to be housed singly after surgery. The caging, bedding and environmental enrichment need to be appropriate to prevent the tether becoming entangled and the wound contaminated. In addition, the bedding needs to be sand free.

Small cannulas will increase the risk of blood clotting  (large cannulae can abrade the blood vessel wall). To prevent this, the cannula requires regular maintenance, (e.g. Regular flushing with an appropriate lock solution. See our preventing thrombosis page for more information).

Blood should be collected aseptically. Usually, 0.1 - 0.5 ml can be taken per sample. Depending on the sample volume and scientific purpose, up to six samples over a two hour period or up to 20 samples over a 24-hour period may be taken. Sterile saline with anticoagulant should be flushed into the cannula after blood sampling to prevent the blood from clotting. A pin is then inserted into the exteriorised end of the cannula, which stops the blood from flowing. A sterile locking solution can be used to lock the cannula after a series of samples have been taken, allowing flushing to be avoided for a number of days.

The following should be checked daily: 

• Skin in contact with the jackets should be checked for abrasion.
• The jacket should be checked for tightness.
• Wound sites should be checked for infection/bruising/swelling/haemorrhage.
• The cannula should be checked for patency (without blockage).
• The weight of the guinea pig (remember weight will include that of the device).

Changes in any of the above may require veterinary advice or treatment, or may indicate that a humane endpoint has been reached and appropriate action should be taken.

Summary

Resources and references

• Nau R, Schunck O (1993). Cannulation of the lateral saphenous vein-a rapid method to gain access to the venous circulation in anaesthetized guineapigs. Laboratory Animals, 27(1): 23-25
• Birck A, Malene M (2014). Non-terminal blood sampling techniques in guinea pigs. Journal of Visualized Experiments, JoVE 92: e51982-e51982
• Gunaratna PC, Kissinger PT, Kissinger CB, Gitzen JF (2004). An automated blood sampler for simultaneous sampling of systemic blood and brain microdialysates for drug absorption, distribution, metabolism and elimination studies. Journal of Pharmacological and Toxicological Methods, 49(1): 57-64
• Nolan TE, Klein HJ (2002). Methods in vascular infusion biotechnology in research with rodents. ILAR Journal, 43(3): 175-182.

Blood vessel cannulation in other animals

All blood sampling techniques in the guinea pig