Long-term repeated access to blood vessels for sampling, administering drug compounds and other substances, or measuring blood pressure in laboratory animals is facilitated by implanting catheters. Cannulation can be considered for long-term sampling or multiple sampling over a relatively short time period.
When correctly implanted, catheters can reduce the stress and discomfort associated with multiple sampling techniques such as repeated restraint and needle stick. In addition to blood sampling, catheterisation can also be considered for repeated substance administration or continuous ambulatory infusion. Catheters can be used to access deep, normally inaccessible vessels (e.g. the hepatic portal vein) and temporary cannulas can also be considered for superficial veins. Recent technical developments have made automated blood sampling possible in animals with implanted catheters (Holmberg and Pelletier 2009).
The ethical review of research protocols proposing to use implanted catheters should carefully weigh the benefits against the costs of the surgical procedures required to implant catheters (e.g. potential pain, discomfort and distress) and the risk of long term complications, such as infection, thrombosis and reactions to implant materials (Morton et al. 2001).
The main challenges to successful long term vascular access are:
- Preventing thrombosis, which can lead to catheter and vessel blockage (occlusion).
- Using apppropriate catheter material, design and construction.
- Preventing catheter-related infection and managing cutaneous exit sites.
Good planning and experimental design are essential to ensure optimum research outcomes from animals with vascular catheters.
We have a number of pages dedicated to vascular catheters:
Resources and references
- Holmberg A & Pelletier R (2009) Automated blood sampling and the 3Rs. London: NC3Rs
- LASA (2010). Guiding principles for preparing for and undertaking aseptic surgery: A report by the LASA Education, Training and Ethics section
- Nolan, T. E., & Klein, H. J. (2002). Methods in vascular infusion biotechnology in research with rodents. ILAR journal, 43(3), 175-182
- Morton, D. B., Jennings, M., Buckwell, A., Ewbank, R., Godfrey, C., Holgate, B., & Verschoyle, R. (2001). Refining procedures for the administration of substances. Laboratory animals, 35(1), 1-41
- Morton, D. B. (1993). Removal of blood from laboratory mammals and birds. Lab Animal 27: 1-22