Patent ID: 7717856

Claim:
A sphygmomanometer, comprising: (a) an elongated tube; (b) an air chamber coupled to a first end of said tube; (c) a liquid chamber coupled to a second end of said tube, said liquid chamber partially filled with fluid and couplable to a source of external pressure; (d) an offset section proximate the second end of said elongated tube having a liquid offset channel of a significantly reduced cross-sectional area so as to reduce the effect of fluid level changes on pressure measurement accuracy; and (e) at least one ventilation valve coupled to one of said elongated tube and said air chamber operative to vent said elongated tube and said air chamber to atmosphere, including a pressure switch coupled to an external pressure source and a barometric pressure and pressure error monitor coupled to said pressure switch and wherein said pressure switch on closing, closes an electrical circuit coupled to said barometric pressure and pressure error monitor causing said barometric pressure and pressure error monitor to become activated.