MEASURING BLOOD PRESSURE OF THE UNRESTRAINED, UNHHEATED RAT
We have been able to overcome two basic drawbacks of non-invasive BP (M,S,D,
HR) measurements (NIBP) in laboratory rat, which are:
A.Heating animal above room temperature to increase circulation in the rat's
tail, and
B.Placing rat in the restrainer during measurement.
In our system measurements are performed in 20 degree C. room temperature and
rat is not restrained in the animal holder. These two factors eliminate basic
BP measurement errors, common in other systems, which are due to the stress
inflicted on animal during measurement.
We have been able to measure non-invasively BP of unrestrained and unheated rat
using Columbus Instruments, "Respiromax" NIBP Computer. Method involves two
small cuffs, one for tail occlusion and second used as a microphone to sense
blood pulsation. Thin air tubes lead from the "Respiromax" NIBP Computer via
swivel to the tail cuffs placed on the rat's tail. Specially designed filter
minimizes artifacts from animal movements, but unfortunately, the reliable BP
measurements are still only possible during the short periods when animal is
resting. When making single BP test on multiple animals it takes usually 2-3
min to obtain reliable first measurement on each new animal. Measurements are
automatic under computer control. User has a choice to use restrainer for
prolonged BP monitoring without close supervision.
Let me know if you like more information about this system.
Jan Czekajewski, Ph.D.
janczek at aol.com
