Process and apparatus for the real time adaptive filtering of catheter pressure measurements
First Claim
1. In a process for measuring the catheter fluid pressure of a patient using a pressure transmission line and a pressure transducer to convert the pressure into an electrical signal and indicating the patient pressure corresponding to the electrical signal with a pressure indicator, the improvement comprising the steps of disposing a tunable active filter in the single path between the transducer and the pressure indicator and adapting the frequency parameters of the filter in real time to that of the catheter by periodically applying a negative pressure impulse to the pressure transmission line instead of the patient pressure to obtain a frequency domain transfer function response to each impulse and adjusting the filter parameters to each impulse response to compensate for inaccuracies in the overall frequency response.
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Abstract
A process and apparatus for measuring the catheter fluid pressure of a patient wherein a pressure transducer is used to convert the pressure into an electrical signal and a pressure indicator indicates the pressure corresponding to the electrical signal. A turnable active filter is disposed in the signal path between the transducer and the pressure indicator and the frequency parameters of the filter are adapted to that of the catheter in real time.
60 Citations
18 Claims
- 1. In a process for measuring the catheter fluid pressure of a patient using a pressure transmission line and a pressure transducer to convert the pressure into an electrical signal and indicating the patient pressure corresponding to the electrical signal with a pressure indicator, the improvement comprising the steps of disposing a tunable active filter in the single path between the transducer and the pressure indicator and adapting the frequency parameters of the filter in real time to that of the catheter by periodically applying a negative pressure impulse to the pressure transmission line instead of the patient pressure to obtain a frequency domain transfer function response to each impulse and adjusting the filter parameters to each impulse response to compensate for inaccuracies in the overall frequency response.
- 7. In an apparatus for measuring the catheter fluid pressure of a patient of the type having a pressure transmission line, a pressure transducer for converting catheter pressure into an electrical signal and a pressure indicator for indicating patient corresponding to the electrical signal, the improvement comprising a tunable active notch filter disposed in the signal path between the transducer and the indicator and means for adapting the frequency parameter of the filter in real time to the frequency characteristics of the catheter comprising means for periodically applying a negative pressure impulse to the pressure transmission line instead of the patient pressure to effect a frequency domain transfer function response to each impulse and means for adjusting the parameters of the filter to each impulse response to compensate for inaccuracies in the overall frequency response.
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13. A device for effecting the real time adaptive filtering of the electrical signal output of a pressure transducer sensing fluid pressure in a pressure line, comprising:
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a. a tunable active notch filter for receiving the output of the transducer at the input thereof; b. means for periodically applying a negative pressure impulse to the pressure line instead of the fluid pressure to obtain a frequency domain transfer function response to each impulse; and c. means for adjusting the tunable parameters of the active filter to each impulse response to compensate for the frequency response of the pressure line. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification