Blood pressure signal processing
AssigneeKoninklijke Philips N.V.
InventorCHRISTOPH FLORIAN FRANCK
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Abstract
The invention provides a method for filtering an invasive blood pressure (IBP) measurement signal based on use of a low pass filter with a frequency response curve which is adapted to exhibit shelving behavior, whereby a higher frequency portion of the passband exhibits greater attenuation behavior than a typical low-pass filter. This has the effect of suppressing underdamping and catheter whip artefacts without eliminating signal components at frequencies in the higher frequency portion of the passband.
Claims15
A processing device for use with an apparatus for invasively measuring a blood pressure inside a portion of the cardiovascular system, the processing device comprising:
- receive circuitry adapted to receive a blood pressure measurement signal indicative of a pressure inside a portion of the cardiovascular system, and
- an electronic filter arranged to filter the blood pressure measurement signal,
- wherein the electronic filter is a low pass filter;
- wherein a passband of the filter has a lower frequency range with a lower boundary of 0 Hz, and wherein the passband of the filter further has an upper frequency range spanning from an upper boundary of the lower frequency range to a cut-off frequency of the filter;
- wherein, across the lower frequency range of the passband, a gain of the filter (G(f)) is greater than or equal to about −0.5 dB;
- wherein, across the higher frequency range of the passband, the gain of the filter (G(f)) is between about −0.5 dB and −3 dB,
- wherein an average gain of the filter in the higher frequency range is less than about −1.7 dB, and/or the average gain of the filter across a frequency range spanning the whole of both the lower frequency range and the higher frequency range is less than about −1.2 dB;
- wherein a proportion of the total passband frequency width within which the gain remains above −0.5 dB is less than 33%;
- wherein the higher frequency range spans from the upper boundary of the lower frequency range to the cut-off frequency of the filter, and wherein the cut-off frequency of the filter is at least 10 Hz.
An electronic filter for filtering an invasive blood pressure signal indicative of a pressure inside a portion of the cardiovascular system, the signal received from an invasive blood pressure measurement apparatus,
- wherein the filter is a low pass filter;
- wherein a passband of the filter has a lower frequency range with a lower boundary of 0 Hz, and wherein the passband of the filter further has an upper frequency range spanning from an upper boundary of the lower frequency range to a cut-off frequency of the filter;
- wherein, across the lower frequency range of the passband, a gain of the filter (G(f)) is greater than or equal to about −0.5 dB;
- wherein, across the higher frequency range of the passband, the gain of the filter (G(f)) is between about −0.5 dB and −3 dB,
- wherein an average gain of the filter in the higher frequency range is less than about −1.7 dB, and/or the average gain of the filter across a frequency range spanning both the lower frequency range and the higher frequency range is less than about −1.3 dB or −1.2 dB;
- wherein a proportion of the total passband frequency width within which the gain remains above −0.5 dB is less than 33%;
- wherein the higher frequency range spans from the upper boundary of the lower frequency range to the cut-off frequency of the filter, wherein the cut-off frequency of the filter is at least 10 Hz.
A method comprising:
- receiving from an invasive blood pressure measurement apparatus a blood pressure signal indicative of a pressure inside a portion of the cardiovascular system, and
- processing the blood pressure signal with an electronic filter,
- wherein the electronic filter is a low pass filter;
- wherein a passband of the filter has a lower frequency range with a lower boundary of 0 Hz, and wherein the passband of the filter further has an upper frequency range spanning from an upper boundary of the lower frequency range to a cut-off frequency of the filter;
- wherein, across the lower frequency range of the passband, a gain of the filter (G(f)) is greater than or equal to about −0.5 dB;
- wherein, across the higher frequency range of the passband, the gain of the filter (G(f)) is between about −0.5 dB and −3 dB, and
- wherein an average gain of the filter in the higher frequency range is less than about −1.7 dB, and/or the average gain of the filter across a frequency range spanning both the lower frequency range and the higher frequency range is less than about −1.2 dB;
- wherein a proportion of the total passband frequency width within which the gain remains above −0.5 dB is less than 33%;
- wherein the higher frequency range spans from the upper boundary of the lower frequency range to the cut-off frequency of the filter, wherein the cut-off frequency of the filter is at least 10 Hz.
Dependencies are inferred from the claim text.