Mitigation of respiratory artifact in blood pressure signal using line segment smoothing
First Claim
1. A blood pressure monitoring apparatus, comprising:
- at least one pressure transducer which senses a patient'"'"'s blood pressure and outputs a blood pressure signal;
an A/D converter which samples said blood pressure signal and outputs blood pressure samples;
a microprocessor which processes said blood pressure samples to determine blood pressure characteristic values representative of a patient'"'"'s blood pressure, said microprocessor including respiration artifact reduction software which reduces respiratory artifacts in said blood pressure samples by determining, for each heart beat detected in said blood pressure samples, the blood pressure at a median point of a line connecting a blood pressure characteristic value for a current heart beat with a corresponding blood pressure characteristic value for a heart beat a predetermined number of heart beats prior to said current heart beat;
a display buffer which stores a value of the blood pressure of said median point determined by said microprocessor as the blood pressure characteristic value for the current heart beat; and
a display monitor which displays the blood pressure characteristic values stored in said display buffer as indicative of the patient'"'"'s blood pressure.
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Abstract
A blood pressure monitoring apparatus which reduces the effects of respiration artifacts in the blood pressure samples prior to display by determining, for each heart beat detected in the blood pressure samples, the blood pressure at a median point of a line connecting a systolic, diastolic, or mean value for a current heart beat with a corresponding systolic, diastolic, or mean value for a heart beat N-1 heart beats prior to the current heart beat. The median blood pressure value for the current heart beat is then averaged with the blood pressure values of the median points of numerous previous heart beats to the current heart beat, and the resulting average is output to the display as indicative of the systolic, diastolic, or mean pressure for the current heart beat. This process is repeated for each heart beat, as desired, until the systolic, diastolic, and mean pressures are determined for each heart beat. The method is advantageous in that it favors stable parts of the blood pressure waveform (end expiratory portions) yet actively smooths the variable parts of the blood pressure waveform.
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Citations
18 Claims
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1. A blood pressure monitoring apparatus, comprising:
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at least one pressure transducer which senses a patient'"'"'s blood pressure and outputs a blood pressure signal; an A/D converter which samples said blood pressure signal and outputs blood pressure samples; a microprocessor which processes said blood pressure samples to determine blood pressure characteristic values representative of a patient'"'"'s blood pressure, said microprocessor including respiration artifact reduction software which reduces respiratory artifacts in said blood pressure samples by determining, for each heart beat detected in said blood pressure samples, the blood pressure at a median point of a line connecting a blood pressure characteristic value for a current heart beat with a corresponding blood pressure characteristic value for a heart beat a predetermined number of heart beats prior to said current heart beat; a display buffer which stores a value of the blood pressure of said median point determined by said microprocessor as the blood pressure characteristic value for the current heart beat; and a display monitor which displays the blood pressure characteristic values stored in said display buffer as indicative of the patient'"'"'s blood pressure. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A blood pressure monitoring apparatus, comprising:
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means for sensing a patient'"'"'s blood pressure and outputting a blood pressure signal; means for sampling said blood pressure signal and outputting blood pressure samples; means for processing said blood pressure samples to determine blood pressure characteristic values representative of a patient'"'"'s blood pressure, said processing means including means for reducing respiratory artifacts in said blood pressure samples by determining, for each heart beat detected in said blood pressure samples, the blood pressure at a median point of a line connecting a blood pressure characteristic value for a current heart beat with a corresponding blood pressure characteristic value for a heart beat a predetermined number of heart beats prior to said current heart beat, and for storing a value of the blood pressure of said median point as the blood pressure characteristic value for the current heart beat; and display means for displaying the blood pressure characteristic values determined by said processing means as indicative of the patient'"'"'s blood pressure. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method of determining a patient'"'"'s blood pressure, comprising the steps of:
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applying at least one transducer to the patient so as to sense the patient'"'"'s blood pressure and outputting a blood pressure signal; sampling the blood pressure signal and outputting blood pressure samples; processing the blood pressure samples to determine blood pressure characteristic values representative of the patient'"'"'s blood pressure, said processing step including the steps of detecting the patient'"'"'s heart beat from said blood pressure samples, reducing respiratory artifacts in said blood pressure samples by determining, for each heart beat detected in said blood pressure samples, the blood pressure at a median point of a line connecting a blood pressure characteristic value for a current heart beat with a corresponding blood pressure characteristic value for a heart beat a predetermined number of heart beats prior to said current heart beat, and storing a value of the blood pressure of said median point as the blood pressure characteristic value for the current heart beat; and displaying the blood pressure characteristic values determined in said processing step as indicative of the patient'"'"'s blood pressure. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification