Method for noninvasive blood-pressure measurement by evaluation of waveform-specific area data

A noninvasive, oscillometric blood-pressure measurement method to determine blood-pressure parameters derived from data acquired relative to blood-pressure-induced pressure waveforms, said method promoting the rapid acquisition and verification of such data, and in operative condition relative to a blood vessel in a living subject, comprising

• establishing in a means for producing a baseline counterpressure adjacent such vessel a predetermined beginning counterpressure above systolic pressure, thus to occlude the vessel,
• progressively reducing counterpressure in steps from a beginning counterpressure step to a predetermined ending counterpressure step,
• during said reducing, monitoring the waveforms of blood-pressure-induced changes in the pressure in such means,
• on the basis of said monitoring, developing and storing waveform-specific partial-area data, and
• determining from such data:
• (a) means arterial pressure to the lowest baseline counterpressure corresponding in time with occurrence of the blood-pressure waveform associated with the largest area-data value;
• (b) systolic pressure to be the baseline counterpressure corresponding in time with occurrence of the blood-pressure waveform whose associated area-data value has a first predetermined fractional relationship with the value identified above in subparagraph (a);
• and
• (c) diastolic pressure to be the baseline counterpressure corresponding in time with occurrence of the blood-pressure waveform whose associated area-data value has a second predetermined fractional relationship with the value identified above in subparagraph (a).

An artifact-rejection method to be used with noninvasive blood-pressure measuring apparatus that determines blood-pressure parameters derived from data acquired relative to blood-pressure-induced pressure waveforms, said method comprising:

• in a means for producing a baseline counterpressure adjacent a blood vessel in a living subject, progressively reducing such counterpressure in counterpressure steps from a predetermined beginning, occluding baseline counterpressure above systolic pressure to a predetermined ending baseline counterpressure;
• during said reducing, and for a predetermined number of such counterpressure steps, and at each such step, monitoring a plurality of the waveforms of blood-pressure-induced changes in the pressure of such means;
• on the basis of said monitoring, developing and storing waveform-specific area data;
• at each of such counterpressure steps, choosing a predetermined number of stored, waveform-specific area-data values as indicative of blood pressure and computing an average waveform-specific area value from such chosen values;
• thereafter, from such average values, fitting a curve and, from such curve, predicting an expected-to-be-stored waveform-specific area-data value for a next baseline counterpressure step, and applying experimentally determined bounds to such expected-to-be-stored waveform-specific area-data value;
• modifying said monitoring at such next baseline counterpressure step so that a single waveform-specific area-data value is developed and stored;
• and
• checking whether such single value is within such bounds from said predicting as a way of determining the acceptability of the value.

An artifact-rejection method to be used with noninvasive blood-pressure measuring apparatus that processes two streams of data corresponding to blood-pressure-induced pressure waveforms, said method comprising:

• in a means for producing a baseline counterpressure adjacent a blood vessel in a living subject, progressively reducing such counterpressure in counterpressure steps from a predetermined beginning, blood-vessel-occluding, baseline-counterpressure step above systolic pressure to an ending baseline counterpressure step;
• during said reducing, and at each such counterpressure step, monitoring at least one waveform of blood-pressure-induced changes in the pressure within such means;
• said monitoring including, for each such waveform, acquiring two streams of data, the first such stream corresponding to baseline counterpressure data, and the second such stream corresponding to blood-pressure-induced, pressure-pulsation data,
• viewing such data in three different phases of activity;
• and
• from said viewing, verifying that such waveform is blood-pressure-induced by checking the first such data-phase according to a first, predetermined verification criteria, by checking the second such phase according to a second, predetermined verification criteria, and by checking the third such phase according to a third, predetermined verification criteria.