Method and apparatus for distinguishing between accurate and inaccurate blood pressure measurements in the presence of artifact
First Claim
1. A blood pressure monitor, comprising:
- a blood pressure cuff;
an air pump pneumatically coupled to said blood pressure cuff;
a valve pneumatically coupled to said blood pressure cuff;
a pressure transducer pneumatically coupled to said blood pressure cuff, said pressure transducer generating a signal indicative of the air pressure in said blood pressure cuff and a signal corresponding to oscillometric pulses in said blood pressure cuff;
processor means connected to said pressure transducer and receiving said signal indicative of the air pressure in said blood pressure cuff and said signal corresponding to oscillometric pulses in said blood pressure cuff, said processor means energizing said air pump to inflate said blood pressure cuff, periodically energizing said valve to incrementally reduce the air pressure in said blood pressure cuff, recording the cuff pressure at which each measurement is made and the amplitude of the oscillometric pulses at such cuff pressure, calculating the diastolic, mean arterial and systolic pressures from said table of cuff pressures and oscillometric pulse amplitudes, calculating the average of the diastolic, mean arterial and systolic pressures recorded in said table for a plurality of measurements, comparing the diastolic, mean arterial and systolic pressures recorded in said table for a current measurement to the average of the diastolic mean, arterial and systolic pressures, respectively, and then determining whether artifact has adversely affected the accuracy of any pressure recorded in said table for a current measurement by determining whether a predetermined number of said pressures recorded in said table for a current measurement deviates from their corresponding average pressures by a predetermined value.
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Abstract
A system for determining if a blood pressure measurement made by an automatic blood pressure monitor has been adversely affected by artifact. The system first compares the diastolic, mean arterial and systolic pressures to respective average diastolic, mean arterial and systolic pressures. If all three of these pressures are within a predetermined range of their corresponding average pressures and if the relationship between these pressures conforms to a physiologically realistic model, then the diastolic, mean arterial and systolic pressures obtained from a measurement are considered valid. If more than one of these pressures is outside the predetermined range of its corresponding average pressure, then the measurement is considered to be adversely affected by artifact and is rejected. If only one of these pressures is outside the predetermined range of its corresponding average pressure, then a replacement pressure is calculated for that pressure. The replacement pressure is calculated based on the pressures that are within the predetermined range and on an average of pressures from previous measurements.
69 Citations
30 Claims
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1. A blood pressure monitor, comprising:
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a blood pressure cuff; an air pump pneumatically coupled to said blood pressure cuff; a valve pneumatically coupled to said blood pressure cuff; a pressure transducer pneumatically coupled to said blood pressure cuff, said pressure transducer generating a signal indicative of the air pressure in said blood pressure cuff and a signal corresponding to oscillometric pulses in said blood pressure cuff; processor means connected to said pressure transducer and receiving said signal indicative of the air pressure in said blood pressure cuff and said signal corresponding to oscillometric pulses in said blood pressure cuff, said processor means energizing said air pump to inflate said blood pressure cuff, periodically energizing said valve to incrementally reduce the air pressure in said blood pressure cuff, recording the cuff pressure at which each measurement is made and the amplitude of the oscillometric pulses at such cuff pressure, calculating the diastolic, mean arterial and systolic pressures from said table of cuff pressures and oscillometric pulse amplitudes, calculating the average of the diastolic, mean arterial and systolic pressures recorded in said table for a plurality of measurements, comparing the diastolic, mean arterial and systolic pressures recorded in said table for a current measurement to the average of the diastolic mean, arterial and systolic pressures, respectively, and then determining whether artifact has adversely affected the accuracy of any pressure recorded in said table for a current measurement by determining whether a predetermined number of said pressures recorded in said table for a current measurement deviates from their corresponding average pressures by a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A blood pressure monitor, comprising:
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a blood pressure cuff; an air pump pneumatically coupled to said blood pressure cuff; a valve pneumatically coupled to said blood pressure cuff; a pressure transducer pneumatically coupled to said blood pressure cuff, said pressure transducer generating a signal indicative of the air pressure in said blood pressure cuff and a signal corresponding to oscillometric pulses in said blood pressure cuff; processor means connected to said pressure transducer and receiving said signal indicative of the air pressure in said blood pressure cuff and said signal corresponding to oscillometric pulses in said blood pressure cuff, said processor means energizing said air pump to inflate said blood pressure cuff, periodically, energizing said valve to incrementally reduce the air pressure in said blood pressure cuff, recording the cuff pressure at which each measurement is made and the amplitude of the oscillometric pulses at such cuff pressure, calculating the diastolic, mean arterial and systolic pressures from said table of cuff pressures and oscillometric pulse amplitudes, comparing the relationship between the systolic, diastolic and mean arterial pressures to a physiologically realistic model and determining that said measurement has been adversely affected by artifact if the relationship between the systolic, diastolic or mean arterial pressure varies from said physiologically realistic model by a predetermined value. - View Dependent Claims (12, 13, 14)
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15. A system for calculating a replacement from a table of data containing the diastolic, systolic and mean arterial pressures obtained from a plurality of blood pressure measurements in the event that the accuracy of one of said pressures is adversely affected by artifact, said system comprising:
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means for identifying a pressure in said table that has been adversely affected by artifact; and means for calculating said replacement pressure based on the pressures in said table that have not been adversely affected by artifact and on pressures in said table from previous blood pressure measurements. said system calculating a replacement diastolic pressure according to the formula;
##EQU10## where AVG. RATIO is calculated according to the formula;
##EQU11##
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16. A system for calculating a replacement from a table of data containing the diastolic, systolic and mean arterial pressures obtained from a plurality of blood pressure measurements in the event that the accuracy of one of said pressures is adversely affected by artifact, said system comprising:
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means for identifying a pressure in said table that has been adversely affected by artifact; and means for calculating said replacement pressure based on the pressures in said table that have not been adversely affected by artifact and on pressures in said table from previous blood pressure measurements. said system calculating a replacement systolic pressure according to the formula;
##EQU12## where AVG. RATIO is calculated according to the formula;
##EQU13##
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17. A system for calculating a replacement from a table of data containing the diastolic, systolic and mean arterial pressures obtained from a plurality of blood pressure measurements in the event that the accuracy of one of said pressures is adversely affected by artifact, said system comprising:
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means for identifying a pressure in said table that has been adversely affected by artifact; and means for calculating said replacement pressure based on the pressures in said table that have not been adversely affected by artifact and on pressures in said table from previous blood pressure measurements, said system calculating a replacement mean arterial pressure according to the formula;
space="preserve" listing-type="equation">MEAN ARTERIAL PRESSURE=AVG. RATIO (SYSTOLE-DIASTOLE)+DIASTOLEwhere AVG. RATIO is calculated according to the formula;
##EQU14##
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18. A method of determining whether the diastolic, mean arterial and systolic pressures obtained from a blood pressure measurement have been adversely affected by artifact, said method comprising:
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calculating the average of the diastolic, mean arterial and systolic pressures for a plurality of measurements; comparing the diastolic, mean arterial and systolic pressures for said measurement to the average of the diastolic, mean arterial and systolic pressures, respectively; and determining whether a predetermined number of said pressures obtained by said measurement deviates from their corresponding average pressures by a predetermined value thereby determining whether artifact has adversely affected the accuracy of any pressure obtained by said measurement. - View Dependent Claims (19, 20, 21, 22, 23, 25, 26)
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24. The method of claim 24, wherein said replacement diastolic pressure is calculated according to the formula:
- ##EQU15## where AVG. RATIO is calculated according to the formula;
##EQU16##
- ##EQU15## where AVG. RATIO is calculated according to the formula;
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27. A method of determining whether the diastolic, mean arterial and systolic pressure obtained from a blood pressure measurement have been adversely affected by artifact, said method comprising:
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comparing the relationship between the systolic, diastolic and mean arterial pressures to a physiologically realistic model; and determining that said measurement has been adversely affected by artifact if the relationship between the systolic, diastolic or mean arterial pressure varies from said physiologically realistic model by a predetermined value. - View Dependent Claims (28, 29, 30)
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Specification