Non-Invasive Blood Pressure (NIBP) is widely used for routine BP measurement in awake or anesthetized animals. The basic technique is straightforward: a cuff placed at the base of the tail is inflated to occlude blood flow, then the cuff is slowly deflated while monitoring for the return of pulsatile flow. The cuff pressure at the time of the first appearance of pulses indicates systolic BP.
What separates the various available NIBP systems is the method of pulse detection and measurement. Rats and other rodents control blood flow to the tail as a means of thermoregulation. When the ambient temperature exceeds approximately 28-30oC, blood flow to the tail increases, making NIBP measurements easier. Systems using the less-sensitive piezoelectric sensors require elevated temperatures. The more sensitive photoelectric sensors permit measurement at ambient temperature. The systems sold by CWE are equipped with specially-designed photoelectric sensors optimized for low-temperature measurements. This results in the least stress to the animal as well as the most accurate measurements.
Features and advantages:
● Good accuracy (±6 mmHg) depending on technique
● Intermittent measurement
● Requires software to compute measurements
● Both systolic and diastolic measurement
● Provides Mean BP
● Provides heart rate (HR)
● No surgery required
● Requires restraining animal in holder
● Periodic inflation/deflation of cuff required
● Some systems require warning of animal to increase blood flow in extremities
Note: The photoplethysmographic NIBP systems sold by CWE are inherently more sensitive than piezo sensor systems, and do not normally require animal heating.