Continuous cardiac output derived from the arterial pressure waveform using pattern recognition
First Claim
1. A system for determining the value of a characteristic of the vascular system of a patient from the blood pressure existing in that vascular system, comprising:
- a sensor which senses the blood pressure in the vascular system and which provides a pressure signal representative of that blood pressure;
a digitizer which receives the pressure signal from the sensor and converts the pressure signal into a digitized pressure signal;
a memory having stored therein a plurality of representative pressure waveforms, each representative pressure waveform comprising a set of values of selected features of a respective pressure signal having associated therewith a known value of the characteristic, the memory also storing the known characteristic value corresponding to each representative pressure waveform; and
a processor which;
receives the digitized pressure signal from the digitizer;
extracts at least one feature of the selected set of features from the digitized pressure signal and determines the value of each extracted feature;
compares the value of each extracted feature from the digitized pressure signal to the value of each corresponding feature of representative pressure waveforms stored in the memory;
based on the comparison, selects the representative pressure waveform most similar to the digitized pressure signal; and
provides the characteristic value corresponding to the selected representative pressure waveform asthe value of the characteristic of the vascular system of the patient.
1 Assignment
0 Petitions
Accused Products
Abstract
A system and method of determining cardiac output from a cardiac pressure waveform. The pressure waveform is continuously sensed and converted into a digital data stream. When a complete beat frame of data is sensed, the processor extracts a plurality of features from the sensed waveform which characterize the waveform. These features are compared to stored representative pressure waveforms (RPW'"'"'s) which have a known cardiac output. The RPW'"'"'s are obtained by applying a pattern recognition methodology to pressure waveforms of known cardiac output. In one embodiment the typical shapes function is used. The pattern recognition methodology results in classes and associated cardiac outputs which are stored as the RPW'"'"'s. The features extracted from waveforms representative of unknown cardiac output are thus classified by the comparison to the RPW'"'"'s. When a match is made between the extracted features and an RPW, the cardiac output of the selected RPW is output as the cardiac output of the patient.
-
Citations
32 Claims
-
1. A system for determining the value of a characteristic of the vascular system of a patient from the blood pressure existing in that vascular system, comprising:
-
a sensor which senses the blood pressure in the vascular system and which provides a pressure signal representative of that blood pressure; a digitizer which receives the pressure signal from the sensor and converts the pressure signal into a digitized pressure signal; a memory having stored therein a plurality of representative pressure waveforms, each representative pressure waveform comprising a set of values of selected features of a respective pressure signal having associated therewith a known value of the characteristic, the memory also storing the known characteristic value corresponding to each representative pressure waveform; and a processor which; receives the digitized pressure signal from the digitizer; extracts at least one feature of the selected set of features from the digitized pressure signal and determines the value of each extracted feature; compares the value of each extracted feature from the digitized pressure signal to the value of each corresponding feature of representative pressure waveforms stored in the memory; based on the comparison, selects the representative pressure waveform most similar to the digitized pressure signal; and provides the characteristic value corresponding to the selected representative pressure waveform as the value of the characteristic of the vascular system of the patient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
-
-
17. A method for determining the value of a characteristic of the vascular system of a patient from the blood pressure existing in that vascular system, comprising the steps of:
-
sensing the blood pressure in the vascular system and providing a pressure signal representative of that blood pressure; converting the pressure signal representative of sensed blood pressure into a digitized pressure signal; storing a plurality of representative pressure waveforms, each representative pressure waveform comprising a set of values of selected features of a respective pressure signal having associated therewith a known value of the characteristic and storing the known characteristic value corresponding to each representative pressure waveform; extracting at least one feature of the selected set of features from the digitized pressure signal and determining the value of each extracted feature; comparing the value of each extracted feature from the digitized pressure signal to the value of each corresponding feature of the stored representative pressure waveforms; based on the comparison, selecting the representative pressure waveform most similar to the digitized pressure signal; and providing the characteristic value corresponding to the selected representative pressure waveform as the value of the characteristic of the vascular system of the patient. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
-
Specification