Automatic blood pressure monitor employing artifact rejection method and apparatus
First Claim
1. In a method for using a blood pressure monitor of the type having a blood pressure cuff:
- an air pump in fluid communication with said cuff to direct pressurized air into said cuff, an air valve in fluid communication with said cuff to selectively vent said cuff to atmosphere, a pressure transducer in fluid communication with said cuff generating an output including a pressure signal indicative of a steady state fluid pressure in said cuff corresponding to an occlusive pressure exerted by said cuff on an artery and a transient fluid pressure in said cuff indicative of an amplitude of an oscillometric waveform, a processor in electrical communication with said air pump and said air valve for selectively energizing said air pump or valve to pressurize or depressurize said cuff respectively comprising;
(a) setting the steady state fluid pressure in said cuff to an initial value;
(b) sampling the output of said transducer over a plurality of heartbeats to generate samples of said oscillometric waveform;
(c) prior to identifying the existence of an oscillometric pulse during any period of time, summing the samples of said transducer output taken after one heartbeat with the samples of said transducer output taken at corresponding times after a plurality of other heartbeats to obtain composite samples of said oscillometric waveform over a plurality of heartbeats, said composite samples corresponding to an average oscillometric waveform;
(d) storing said composite samples;
(e) altering the steady state fluid pressure in said cuff;
(f) repeating steps (b)-(e) a plurality of times; and
(g) analyzing said average oscillometric waveforms to determine blood pressure.
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Accused Products
Abstract
A blood pressure monitor capable of measuring blood pressure in the presence of artifact. One embodiment of the blood pressure monitor uses a detector to generate a trigger signal on the occurrence of the R-wave or other point on the ECG waveform. Oscillometric waveform samples taken at the same time after each trigger signal are then summed with each other over many heartbeats to generate an average oscillometric waveform that is used to determine blood pressure by conventional means. Another embodiment of the blood pressure monitor stores oscillometric waveform samples over many heartbeats. The monitor then assumes that the period of the heartbeat has a variety of durations, and it derives respective sets of composite samples by summing the stored samples having the same temporal relationship to the start of each assumed period. The set of composite samples corresponding the a waveform that best matches an actual oscillometric wave is then used to determine blood pressure by conventional means.
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Citations
22 Claims
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1. In a method for using a blood pressure monitor of the type having a blood pressure cuff:
- an air pump in fluid communication with said cuff to direct pressurized air into said cuff, an air valve in fluid communication with said cuff to selectively vent said cuff to atmosphere, a pressure transducer in fluid communication with said cuff generating an output including a pressure signal indicative of a steady state fluid pressure in said cuff corresponding to an occlusive pressure exerted by said cuff on an artery and a transient fluid pressure in said cuff indicative of an amplitude of an oscillometric waveform, a processor in electrical communication with said air pump and said air valve for selectively energizing said air pump or valve to pressurize or depressurize said cuff respectively comprising;
(a) setting the steady state fluid pressure in said cuff to an initial value; (b) sampling the output of said transducer over a plurality of heartbeats to generate samples of said oscillometric waveform; (c) prior to identifying the existence of an oscillometric pulse during any period of time, summing the samples of said transducer output taken after one heartbeat with the samples of said transducer output taken at corresponding times after a plurality of other heartbeats to obtain composite samples of said oscillometric waveform over a plurality of heartbeats, said composite samples corresponding to an average oscillometric waveform; (d) storing said composite samples; (e) altering the steady state fluid pressure in said cuff; (f) repeating steps (b)-(e) a plurality of times; and (g) analyzing said average oscillometric waveforms to determine blood pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
- an air pump in fluid communication with said cuff to direct pressurized air into said cuff, an air valve in fluid communication with said cuff to selectively vent said cuff to atmosphere, a pressure transducer in fluid communication with said cuff generating an output including a pressure signal indicative of a steady state fluid pressure in said cuff corresponding to an occlusive pressure exerted by said cuff on an artery and a transient fluid pressure in said cuff indicative of an amplitude of an oscillometric waveform, a processor in electrical communication with said air pump and said air valve for selectively energizing said air pump or valve to pressurize or depressurize said cuff respectively comprising;
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12. A blood pressure monitor, comprising:
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a blood pressure cuff; an air pump in fluid communication with said cuff to direct pressurized air into said cuff; an air valve in fluid communication with said cuff to selectively vent said cuff to atmosphere; a pressure transducer in fluid communication with said cuff generating an output including a pressure signal indicative of a steady state fluid pressure in said cuff corresponding to an occlusive pressure exerted by said cuff on an artery and a transient fluid pressure in said cuff indicative of an amplitude of an oscillometric waveform; an analog-to-digital converter connected to said transducer sampling the output of said transducer and generating respective digital samples corresponding to the output of said transducer when said samples are taken; and processor means in electrical communication with said analog-digital converter said air pump and said air valve for energizing said air pump and said air valve to set the steady state fluid pressure to a plurality of pressure values, said processor means summing digital samples taken after one heartbeat with digital samples taken at corresponding times after a plurality of other heartbeats to obtain composite samples of said oscillometric waveform over a plurality of heartbeats prior to identifying the existence of an oscillometric pulse during any period of time, and analyzing said composite samples at a plurality of different steady state fluid pressures in said cuff to determine blood pressure. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification