Oscillometric blood pressure monitor with enhanced cuff pressure control

摘要

An automated sphygmomanometer in which the so-called "air effect" (a slow rise or fall in cuff pressure caused by step inflates or deflates) is substantially eliminated by deflating (inflating) the pressure cuff to a pressure lower (higher) than the target pressure, waiting a short time interval, and then inflating (deflating) the pressure cuff to the target pressure. The driving force that causes the air effect to settle out after a step inflate or deflate is proportional to the size of the step change in pressure and is thus greatest during the wait time before the pressure cuff is inflated or deflated to the target pressure. Once at the target pressure, the remaining air effect is counteracted by the incremental air effect introduced by the latter inflate or deflate so that the air effect cancels out. The techniques of the invention provide most improved results for large inflates and deflates of 20mm Hg or more or first deflates after a complete inflate of the pressure cuff where the air effects are most pronounced.