Ambulatory vs Tethered Infusion Systems
The choice between an ambulatory or tethered infusion system became possible with the introduction of infusion pumps that were small, accurate and rugged enough to withstand the rigors of large animal studies. Prior to then, tethered systems using volumetric or syringe driver pumps were necessary. Recent advancements in pump technology, jacket design, catheter material, and surgical techniques have made it possible for preclinical researchers to choose the option that works best for their needs.
Ambulatory systems allow animals unrestrained and untethered freedom of movement. This type of infusion system is ideal for studies that require minimal human intervention or where group-housing is needed. In some countries, long-term tethered infusion in large animals have been reduced or eliminated due to the belief that non-tethered systems reduce stress on the animal subjects. However, ambulatory systems require capture and temporary restraint of the animal each time the reservoir or flow rate needs to be changed. Additionally, constant monitoring of pump function can only be accomplished using remote monitoring software.
Even with the benefits of ambulatory studies, tethered systems are still common. Generally speaking, tethered systems are the norm for rodent studies; this is due to the fact that long-term infusion studies require fluid volumes that cannot be carried by small rodents. If compatible with the study design, implantable infusion pumps can be used in rodents, but the flow rates and volumes are still limited. For larger animals, the choice is more nuanced. Typically, a tethered infusion protocol will be used when frequent changes in test article or flow rate are required. Tethered infusion also reduces the risk of damage to pumps, by moving the pump outside of the animal enclosure.
In short, there are advantages and disadvantages to both systems. Not sure where to start? Contact us and our experienced staff can provide guidance and pricing for a system that works for you. Let us know the species and length of your study and we'll go from there.