US5337750A — Automatic blood pressure monitor employing artifa…

Claim 1

Independent Claim 264 words

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.

Claim 2

Dependent Claim 264 words

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.

Claim 3

Dependent Claim 57 words

The method of claim 1 wherein said composite samples are generated by the steps of: generating a plurality of trigger signals each of which has a predetermined temporal relationship to a respective heartbeat; and summing the said transducer output samples taken after each trigger signal with correspondingly ordered transducer output samples taken after respective other trigger signals.

Claim 4

Dependent Claim 56 words

The method of claim 2 further including the step of dividing each of said composite samples by the number of transducer output samples that have been summed to generate said composite sample so that each of said composite samples is an average of the samples taken at the same time after each of said trigger signals.

Claim 5

Dependent Claim 93 words

The method of claim 2 wherein said composite samples are generated by the steps of: (a) periodically sampling the output of said pressure transducer; checking for the occurrence of said trigger signal; (c) discarding each sample of said pressure transducer samples until said trigger signal occurs; (d) summing the pressure transducer samples taken after said trigger signal occurs for a predetermined period after the occurrence of said trigger signal with correspondingly ordered pressure transducer samples previously taken after respective other trigger signals; and (e) repeating steps a-d for a plurality of trigger signals.

Claim 6

Dependent Claim 31 words

The method of claim 2 wherein the output of said transducer is sampled for a predetermined number of heartbeats after each trigger signal during each value of steady state fluid pressure.

Claim 7

Dependent Claim 97 words

The method of claim 2 wherein the number of heartbeats during which the output of said transducer is sampled at each value of steady state fluid pressure in said cuff is determined by the steps of: comparing a composite sample derived after each heartbeat with a corresponding composite sample derived after a previous heartbeat; and continuing to sample the output of said transducer and derive composite samples during successive heartbeats until the difference between the composite sample derived after a heartbeat and the corresponding composite sample derived after the previous heartbeat is less than a predetermined value.

Claim 8

Dependent Claim 138 words

The method of claim 1 wherein said composite samples are generated by the steps of: (a) storing said transducer output samples for a plurality of heartbeats; (b) assuming that a period between heartbeats is an initial value; (c) summing stored transducer output samples having the same temporal relationship with the start of each assumed period, thereby deriving tentative composite samples; (d) evaluating said tentative composite samples to determine if they correspond to an actual oscillometric waveform, thereby determining that the assumed period is an actual period between heartbeats; (e) if the assumed period is the actual period between heartbeats, adopting said tentative composite samples as said composite samples that are analyzed to determine blood pressure; and (f) if the assumed period is not the actual period between heartbeats, altering the assumed period between heartbeats and repeating steps c-f.

Claim 9

Dependent Claim 29 words

The method of claim 7 wherein said tentative composite samples are evaluated in step (d) by determining if the oscillometric waveform corresponding to said tentative composite samples is periodic.

Claim 10

Dependent Claim 33 words

The method of claim 8 wherein said tentative composite samples are further evaluated in step (d) by determining if the oscillometric waveform corresponding to said tentative composite samples has a single major peak.

Claim 11

Dependent Claim 33 words

The method of claim 7 wherein said tentative composite samples are evaluated in step (d) by comparing to said tentative composite sample to a template of samples corresponding to an actual oscillometric waveform.

Claim 12

Dependent Claim 59 words

The method of claim 7 further including the step of dividing each of said composite samples by the number of transducer output samples that have been summed to generate said composite sample so that each of said composite samples is an average of the transducer output samples taken at the same time after the start of each assumed period.

Claim 13

Dependent Claim 235 words

A blood pressure monitor, comprising: 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.

Claim 14

Dependent Claim 235 words

A blood pressure monitor, comprising: 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.

Claim 15

Dependent Claim 66 words

The blood pressure monitor of claim 12 wherein said blood pressure monitor further includes a trigger signal generator connected to said processor means for producing a trigger signal having a predetermined temporal relationship to each heartbeat, and wherein said processor means derives said composite samples by summing said digital samples taken after each trigger signal with correspondingly ordered digital samples taken after respective other trigger signals.

Claim 16

Dependent Claim 57 words

The blood pressure monitor of claim 13 wherein said processor means further divides each of said composite samples by the number of digital samples that have been summed to generate said composite sample so that each of said composite samples is an average of the samples taken at the same time after each of said trigger signals.

Claim 17

Dependent Claim 27 words

The blood pressure monitor of claim 13 wherein said processor means sums said digital samples only for a predetermined period after the occurrence of each trigger signal.

Claim 18

Dependent Claim 39 words

The blood pressure monitor of claim 13 wherein said processor means determines blood pressure by summing said digital samples during a predetermined number of heartbeats at each of a plurality of different steady state fluid pressures in said cuff.

Claim 19

Dependent Claim 51 words

The blood pressure monitor of claim 13 wherein said processor means sums said digital samples at each steady state fluid pressure in said cuff until the difference between a composite sample derived after a heartbeat and the corresponding composite sample derived after a previous heartbeat is less than a predetermined value.

Claim 20

Dependent Claim 107 words

The blood pressure monitor of claim 12, wherein said blood pressure monitor further includes memory means for storing said digital samples for a plurality of heartbeats, and wherein said processor means determines blood pressure by sequentially deriving sets of tentative composite samples each of which correspond to the sum of digital samples having the same temporal relationship with the start of a respective assumed period between heartbeats until the waveform corresponding to a set of tentative composite samples for an assumed period correspond to an actual oscillometric waveform, said processing means then determining blood pressure by analyzing the tentative composite samples corresponding to the actual oscillometric waveform.

Claim 21

Dependent Claim 43 words

The blood pressure monitor of claim 18 wherein said processing means determines that a set of tentative composite samples for an assumed period correspond to an actual oscillometric waveform by determining if the oscillometric waveform corresponding to said tentative composite samples is periodic.

Claim 22

Dependent Claim 47 words

The blood pressure monitor of claim 19 wherein said processing means does not determine that a set of tentative composite samples for an assumed period correspond to an actual oscillometric waveform unless said tentative composite samples further correspond to an oscillometric waveform having a single major peak.

Claim 23

Dependent Claim 46 words

The blood pressure monitor of claim 18 wherein said processing means determines that a set of tentative composite samples for an assumed period correspond to an actual oscillometric waveform by comparing said tentative composite samples to a template of samples corresponding to an actual oscillometric waveform.

Claim 24

Dependent Claim 59 words

The blood pressure monitor of claim 18 wherein said processor means further divides each of said composite samples by the number of digital samples that have been summed to generate said composite sample so that each of said composite samples is an average of the digital samples taken at the same time after the start of each assumed period.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1997-08-15	1998-02-14	1998-08-16	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2001-08-15	2002-02-14	2002-08-16	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2005-08-15	2006-02-14	2006-08-16	$7700.00	Window Closed / Lapsed

Automatic blood pressure monitor employing artifact rejection method and apparatus

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