Continuous non-invasive blood pressure monitoring using concentrically interlocking control loops.

A new method and apparatus for non-disruptive blood pressure (BP) recording in the finger based on the vascular unloading technique is introduced. The instrument, in contrast to intermittent set point readjustments of the conventional vascular unloading technique, delivers BP without interruptions, thus refining the Penáz' principle. The method is based on concentrically interlocking control loops for correct long-term tracing of finger BP, including automatic set point adaptation, light control and separate inlet and outlet valves for electro-pneumatic control. Examples of long-term BP recordings at rest and during autonomic function tests illustrate the potential of the new instrument.