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US 5,820,550 AGranted
Pulse oximeter with improved accuracy and response time
AssigneeNovametrix Medical Systems, Inc.
InventorsMichael John Ross Polson, Gregory Llewelyn Morris
Life of this patent
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Abstract
An improved pulse oximeter apparatus and method for the measurement of oxygen saturation in the blood, which is faster and more accurate than conventional pulse oximeters. Improved speed and accuracy is attained by elimination of normalization and feedback circuitry and the use of analog to digital converting devices having a wide dynamic range along with a sophisticated computer analysis. The instant invention eliminates inaccuricies resulting from channel matching errors, and detects and eliminates aberrant input data.
Claims14
An apparatus for measuring and displaying oxygen saturation levels present in pulsating blood flow in a living person, comprising:
- data generating means for generating incoming data structures produced by directing light having a first wavelength and light having a second wavelength, towards said pulsating blood flow, and detecting said light after passage through said pulsating blood flow;
- data processing means for processing said incoming data structures so as to produce output data structures, each said output data structure including data representative of the oxygen saturation level present in one or more pulsations of said pulsating blood flow;
- data storage means for storing at any instant, a plurality of output data structures produced from said data processing means;
- data scanning means for scanning data in said stored output data structures, and generating for a first number of stored output data structures, a set of parameters which provide a statistical measure of confidences for said first number of stored output data structure;
- data validation means for validating a second number of said output data structures on the basis of one or more of said set of parameters by operably controlling said data scanning means to mark each said output data structure in said second number thereof as being valid for use in computing oxygen saturation levels to be displayed, each said output data structure not validated by said data validation means being precluded from use in the computation of oxygen saturation levels;
- computing means for computing the oxygen saturation level of said pulsating blood flow, on the basis of data contained in said second number of stored output data structures;
- an output data averaging means for averaging oxygen saturation level data contained in the second number of stored output data structures;
- and
- display means for periodically displaying said computed oxygen saturation level of said pulsating blood flow.
6 more elements
A method of measuring and displaying average oxygen saturation levels present in pulsating blood flow in a living person, said method comprising the steps:
- (a) directing light having a first wavelength and light having a second wavelength, towards a tissue sample carrying a pulsating blood flow;
- (b) detecting the light of said first and second wavelengths, after passage through said tissue sample, and generating, in response thereto, a first analog electrical signal related to said first wavelength, and a second analog electrical signal related to said second wavelength;
- (c) converting within a pulse oximeter said first and second analog electrical signals, into first and second digital signals, respectively;
- (d) processing said first and second digital signals so as to compute, for each pulsation in said pulsating blood flow, (i) an oxygen saturation level data element, and (ii) an associated data element containing pulse time interval data or artifact data;
- (e) storing said oxygen saturation level data elements and said associated data elements computed over a predetermined period of time;
- (f) selectively validating certain of said oxygen saturation level data elements using said associated data elements, so as to produce validated oxygen saturation level data elements for use in computing average oxygen saturation levels for visual display;
- (g) averaging a selected number of said validated oxygen saturation level data elements so as to produce data representative of an average oxygen saturation level;
- and
- (h) visually displaying from said pulse oximeter, said average oxygen saturation levels for use in monitoring said living person.
6 more elements
A pulse oximeter for measuring and displaying oxygen saturation levels present in pulsating blood flow in a living person, comprising:
- light direction means for directing light having a first wavelength and light having a second wavelength, towards a tissue sample carrying a pulsating blood flow;
- light detection means for detecting the light of said first and second wavelengths, after passage through said tissue sample, and for generating, in response thereto, a first electrical signal related to said first wavelength, and a second electrical signal related to said second wavelength;
- signal conversion means for converting said first and second electrical signals, into first and second digital signals, respectively;
- computer processing means for processing said first and second digital signals so as to compute an oxygen saturation level and associated data for one or more pulsations in said pulsating flow of flood;
- storage means for storing said oxygen saturation levels and associated data computed over a predetermined period of time;
- data validating means for selectively validating computed oxygen saturation levels on the basis of said associated data;
- averaging means for computing an average oxygen saturation level for display using a number of said computed oxygen saturation levels;
- and
- display means for visually displaying each said average oxygen saturation levels computed by said averaging means.
6 more elements
Dependencies are inferred from the claim text.