Detection of oscillometeric blood pressure complexes using correlation
First Claim
1. An automated sphygmomanometer apparatus, comprising:
- an inflatable and deflatable pressure cuff;
inflating means operatively coupled to said cuff for selectively applying a medium under pressure to said cuff for inflating and pressurizing said cuff;
cuff pressure sensing means coupled to said cuff for sensing cuff pressure including any arterial blood pressure oscillations therein and outputting a cuff pressure signal;
deflating means operatively coupled to said cuff for selectively relieving pressure from said cuff;
control means for controlling said inflating means to inflate said cuff and said deflating means to deflate said cuff during respective blood pressure determinations of a patient at respective cuff pressure levels;
means for detecting said arterial blood pressure oscillations at respective cuff pressure levels during said respective blood pressure determinations of said patient, said detecting means including means for correlating said cuff pressure signal with a predetermined template representing attributes of a known arterial blood pressure oscillation and for determining the presence of an arterial blood pressure oscillation based on a result of said correlation; and
processing means for calculating a patient'"'"'s blood pressure from arterial blood pressure oscillations detected by said detecting means.
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Abstract
An automated sphygmomanometer which stores the attributes for all oscillation complexes at each pressure step and compares the stored waveform data to a template containing the attributes of a "clean" oscillation complex from a present or previous NIBP determination or from a standard template determined from a broad population of patients. Preferably, an oscillation complex near MAP is selected as the template. After the oscillation complexes have been gathered, correlation values for each new oscillation complex in the stored waveform data and the template are calculated using correlation calculations from detection theory. All oscillation complexes which highly correlate with the template (their correlation values are above a given threshold) are maintained as "good" oscillation data, while the remainder of the oscillation complexes are ignored as corrupted by artifact data. Artifact-reduced data may then be used in the blood pressure calculation. Similar correlation techniques are also used at each pressure step in a real-time manner to detect the presence of an oscillation complex during a step inflate or deflate blood pressure measurement.
56 Citations
29 Claims
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1. An automated sphygmomanometer apparatus, comprising:
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an inflatable and deflatable pressure cuff; inflating means operatively coupled to said cuff for selectively applying a medium under pressure to said cuff for inflating and pressurizing said cuff; cuff pressure sensing means coupled to said cuff for sensing cuff pressure including any arterial blood pressure oscillations therein and outputting a cuff pressure signal; deflating means operatively coupled to said cuff for selectively relieving pressure from said cuff; control means for controlling said inflating means to inflate said cuff and said deflating means to deflate said cuff during respective blood pressure determinations of a patient at respective cuff pressure levels; means for detecting said arterial blood pressure oscillations at respective cuff pressure levels during said respective blood pressure determinations of said patient, said detecting means including means for correlating said cuff pressure signal with a predetermined template representing attributes of a known arterial blood pressure oscillation and for determining the presence of an arterial blood pressure oscillation based on a result of said correlation; and processing means for calculating a patient'"'"'s blood pressure from arterial blood pressure oscillations detected by said detecting means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of determining a patient'"'"'s blood pressure using an automatic oscillometric blood pressure monitor comprising a cuff, means for inflating and deflating said cuff, means for measuring arterial blood pressure oscillation complexes through measurement of time varying pressures within said cuff, and means for searching for arterial blood pressure oscillation complexes at respective cuff pressure levels, said method of determining a patient'"'"'s blood pressure comprising the steps of:
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(a) selectively inflating and deflating said cuff to a cuff pressure level in order to search for arterial blood pressure oscillation complexes of said patient; (b) detecting said arterial blood pressure oscillations at said cuff pressure level by correlating samples of an output signal from said arterial blood pressure oscillation complex measuring means with a predetermined template representing attributes of a known arterial blood pressure oscillation, and by determining the presence of an arterial blood pressure oscillation complex based on a result of said correlation; (c) repeating steps (a) and (b) for subsequent cuff pressure levels until an oscillometric envelope of arterial blood pressure oscillation complexes has been determined; and (d) calculating a patient'"'"'s blood pressure from said oscillometric envelope. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification