Human subjects
In humans, automated NIBP systems can sample changes in relative blood pressure over time, simulating a real-time blood pressure measurement. Non-invasive blood pressure derived from a human subject is typically sampled using an approximation derived from a waveform sampled at the finger. Various algorithms and reconstructions are applied to derive an approximation of arterial blood pressure. These signals are typically used as an indicator of autonomic function, blood pressure changes in exercise, and cardiovascular health.
Rodent subjects
In rodents, NIBP measurement is performed using an occlusion method. A cuff is inflated around the major artery running through the tail. As this pressure is released, and measured, a pulse transducer indicates the return of blood flow to the artery. Systolic pressure can be estimated by finding the pressure at which this pulse returns to the tail.