- Resources and references
- Blood vessel cannulation technique in other animals
- All blood sampling techniques in the rat
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 rat 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. Rats 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) or the base of the tail (via a tail cuff and tether system). The use of a tail cuff is preferable to a jacket as the percentage of adverse effects has been found to be 1% of animals with the tail cuff compared to 5-10% for jacketed models. The tail cuff model also has minimal weight loss after surgery, whilst in the jacketed model the rat takes at least 24 hours to regain pre-operative weight. The use of a subcutaneous access port should be explored as it can 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 rats 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 sange free.
The cannula is small, which can promote blood clotting (larger cannulae can abrade the blood vessel wall). To prevent this, the cannula requires regular maintenance, (e.g. flushing with an anticoagulant).
Blood should be collected aseptically. Usually 0.1 - 0.2 ml can be taken per sample, and depending on the sample volume and scientific justification, 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
- The skin in contact with the jackets should be checked for abrasion.
- The jacket should be checked for tightness.
- The tail cuff should be checked for tightness and the tail for swelling.
- Wound sites should be checked for infection/bruising/swelling/haemorrhage.
- The cannula should be checked for patency.
- The weight of the rat (for recovery work).
|Number of samples||Depending on sample volume, up to six samples may be taken in a two hour period or up to 20 samples over a 24-hour period.|
|Sample volume||0.1 - 0.2 ml|
|Equipment||23G - 25G cannula|
|Staff resource||One person is required to take the blood sample. However, further staff resource is required for surgery, post-operative care for up to five days after surgery, and daily animal observations post-surgery.|
- Arlund E, Heyl W (1997), Low maintenance high patency vascular cannulation in the rat, Taconic Technical Library, National AALAS Meeting, Poster P29
- A good practice guide to the administration of substances and removal of blood, including routes and volumes.
- Lucas RL, Lentz KD, Hale AS (2004), Collection and preparation of blood products. Clinical Techniques in Small Animal Practice. 19(2) 55-62
- Guo Z, Zhou L (2003), Dual tail catheters for infusion and sampling in rates as an efficient platform for metabolic experiments. Lab Animal. 32(2), 45-48
- Effects of cannulation surgery and restraint stress on the plasma corticosterone concentration in the rat: Application of an improved corticosterone HPLC assay.
- Impact of chronic catheterisation and automated blood sampling (Accusample) on serum corticosterone and fecal immunoreactive corticosterone metablitues and immunoglobulin A in male rats.
- De Jong WH, Timmerman A Van Raaij MTM (2001), Long term cannulation of the vena cava of rats for blood sampling: local and systemic effects observed by histopathology after six weeks of cannulation. Laboratory Animals. 35(3) 243-248
- Methods of vascular infusion biotechnology in research with rodents.
- Removal of blood from laboratory animals and birds.
- Kucharski J, Jana B (2003), The cannulation of the caudal caval vein through the femoral vein in the pig for endocrine research. Polish Journal of Veterinary Science. 6(2) 87-92