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US 4,223,682 AGranted
Beat-to-beat systolic and diastolic indicator
AssigneeHewlett-Packard Company
InventorAllan P. Sherman
Life of this patent
Estimating the term…
Abstract
Apparatus and method are disclosed for deriving the maximum and minimum peaks of a wave representing blood pressure by comparing it with offsets that may be arbitrarily set or derived from the blood pressure signal, which offsets are alternatively added to and subtracted from the approximate mean of the blood pressure signal.
Claims14
Apparatus for identifying the occurrence of cycles of dominant amplitudes in an information signal which may also contain other variations in amplitude wherein the cycles may have different durations, comprising
- an input terminal to which an information signal may be applied,
- filtering means for deriving at its output a filtered signal representing an average value of an information signal applied to said input terminal,
- adding means for producing a reference signal at its output, said adding means having first and second inputs, said first input being coupled to the output of said filtering means,
- comparing means having first and second inputs and an output, said first input being coupled to said input terminal so as to receive an information signal when present thereat, said second input being coupled to receive the reference signal at the output of said adding means, said comparing means producing at its output a control signal having a first value while the values of the signal at the first input of the comparing means is greater than the value represented by the signal applied to its second input and having a second value while the value of the signal applied to the first input of the comparing means is less than the value represented by the signal applied to its second input, and
- offset deriving means responsive to said control signal for applying an offset value to the second input of said adding means of such polarity as to cause the value of the reference signal at the output of said adding means to shift to a value having a polarity with respect to the average value provided by said filtering means that is opposite to the polarity of a signal at said input terminal with respect to the references value.
2 more elements
Apparatus for deriving a value representing at least one of the systolic and diastolic blood pressure values for a single heartbeat, comprising
- an input,
- means for applying values representing the variations of blood pressure with time to said input,
- means for deriving an average value representing an average of the blood pressure represented by the values applied to said input,
- means providing an offset value,
- means for combining said offset value with the average value to provide a reference value,
- peak value detecting means for detecting at least one of the systolic and diastolic blood pressures represented by values at said input, and
- means for causing said peak detecting means to detect a peak value occurring while the values representing blood pressures at said input extend in the same direction with respect to said reference value as said average value.
4 more elements
The method of deriving a value representing one of the systolic and diastolic blood pressures from values representing the variation of blood pressure with time, comprising
- deriving an average of the values representing the variation in blood pressure with time,
- combining an offset with average value to form a reference value,
- detecting peak values derived from the values representing the variation with time of the blood pressure that extend in the same direction from the reference value as the average value, and
- means for adjusting the value of said offset to be a function of the difference between an average of the values supplied by said peak value detecting means and said value representing said average of the variation of blood pressure with time.
1 more element
Apparatus for identifying cycles of a signal and for deriving desired peak values of the signal of one polarity, the signal including desired dominant peak values and undesired peak values, comprising
- an input terminal to which the signal may be applied,
- averaging means coupled to said input for deriving at an output thereof an average value of the signal,
- adding means having first and second inputs and an ouput,
- means coupling said first input of said adding means to receive the output of said averaging means,
- means for comparing a signal at said input terminal with the output of said adding means so as to produce a first indication while a signal at said input terminal has said one polarity with respect to the output of said adding means and a second indication while a signal at said input terminal has the opposite polarity with respect to the output of said adder, successive ones of said first and second indications defining a cycle,
- means responsive to said first indication for deriving during the time said first indication is present a signal value corresponding to the greatest peak value of said one polarity of signals present at said input terminal,
- means responsive to said second indication for deriving during the time said second indication is present a signal value corresponding to the greatest peak value of said opposite polarity of signals present at said input terminal,
- means for producing a signal representing an average of peak values derived by said latter mans during previous second indications,
- means coupled to said latter means for deriving an offset value that is a given portion of the difference between the average of peak values derived by said latter means and the said average value of the signal produced by said averaging means, and
- means coupled to said means for deriving an offset value for applying the offset value to the second input of said adding means during said second indication with such polarity as to cause the output of said adding means to shift toward the said one polarity, whereby undesired peaks of said one polarity have to have a greater amplitude in order to change the output of said comparing means from the first indication to the second.
7 more elements
Dependencies are inferred from the claim text.