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Circuit for Monitoring Blood Pressure Measurements

IP.com Disclosure Number: IPCOM000096095D
Original Publication Date: 1964-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Hammer, WE: AUTHOR [+2]

Abstract

Systolic blood pressure is measured by first occluding an artery with a pressure cuff, not shown, and then slowly decreasing the pressure in the cuff until blood pressure pulses are detected. A reading of the cuff pressure at the time of the first pulse gives a measurement of systolic blood pressure. This circuit reduces the possibility of an erroneous reading by permitting the pressure measurement provided by analog to digital converter 1 in response to a first pressure pulse to be recorded only if a second pulse is detected more than .4 and less than 2 seconds after the first pulse. If a second pulse is not received during this period, the ADC 1 reading is rejected on the assumption that the first pulse was not a true blood pressure pulse.

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Circuit for Monitoring Blood Pressure Measurements

Systolic blood pressure is measured by first occluding an artery with a pressure cuff, not shown, and then slowly decreasing the pressure in the cuff until blood pressure pulses are detected.

A reading of the cuff pressure at the time of the first pulse gives a measurement of systolic blood pressure. This circuit reduces the possibility of an erroneous reading by permitting the pressure measurement provided by analog to digital converter 1 in response to a first pressure pulse to be recorded only if a second pulse is detected more than .4 and less than 2 seconds after the first pulse.

If a second pulse is not received during this period, the ADC 1 reading is rejected on the assumption that the first pulse was not a true blood pressure pulse.

Pressure pulse detecting amplifier 2 supplies one input to Negative And 3 while the second input is supplied by the normally positive output of single-shot
6. The first pressure pulse detected by 2 causes single-shot 5 to be turned on through 3 and inverter 4. The leading edge of the output signal from 5 causes 1 to sample the analog cuff pressure and convert it to a digital value, which is stored in register 9.

After .4 seconds the output of 5 returns to its normal up level causing the output of 6 to drop. This output stays down for 1.6 seconds, conditioning one side of And 8 through inverter 7. If a second pulse is detected by 2 during this
1.6 second period, the resulting...