Repeated blood pressure measurement in conscious rodents is usually made with a tail-cuff system. The method is non-invasive, so the same animal can be followed across the whole course of a study, and it suits pharmacology and cardiovascular protocols where treatment effects develop over weeks.
How the measurement is made
An occlusion cuff and a sensor cuff are placed on the tail. The occlusion cuff is inflated above systolic pressure and then released, and the sensor records the reappearance of the pulse. The signal is processed to give systolic, diastolic and mean arterial pressure together with heart rate and, where the software supports it, an estimate of the pulse wave.
Getting usable data
Animals must be accustomed to the restrainer and to the procedure before data are collected, and the laboratory should be quiet and at a stable temperature, because tail blood flow is strongly affected by stress and by cold. Sessions should run at the same time of day, several measurements should be taken and averaged, and the first readings discarded while the animal settles.
Reporting
Report the number of accepted readings, the acclimation period, the ambient temperature and the restrainer type, since all four affect the absolute values obtained.