System and method for transient response and accuracy enhancement for sensors with known transfer characteristics

• US 6,739,337 B2
• Filed: 03/27/2003
• Issued: 05/25/2004
• Est. Priority Date: 03/14/1997
• Status: Expired due to Term

• Current Assignee: Nellcor Puritan Bennett Incorporated (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett Incorporated (Medtronic Plc)
• Inventors: Isaza, Fernando J.
• Primary Examiner(s): Lewis, Aaron J.
• Application Number:
  US10/400,958
• Publication Number:
  US 20030192542A1
• Time in Patent Office: 425 Days
• Field of Search: 128/204.21, 128/204.23, 128/205.23, 128/202.22
• US Class Current: 128/204.21
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: G01F 1/6965 comprising means to store calibration data for flow signal calculation or correction
• CPC Class Codes: G01F 25/10 of flowmeters

Abstract

A parameter of interest being measured by a sensor is estimated from output response data from the sensor and the known transfer function of the sensor, allowing fast and accurate sensor data from sensors having a dynamic characteristic otherwise precluding assessment of the sensor input. A parameter of breathing gas from a ventilator is determined based upon the known transfer function and a plurality of the sensor output signals at predetermined intervals of time, to provide an estimation of the parameter of interest.

Claims

1. In a system for determining a dynamically changing output parameter of interest, the system including an oxygen sensor for determining the output parameter of interest, the oxygen sensor exhibiting a dynamic characteristic having a time constant, resulting in a transient performance of the oxygen sensor, said oxygen sensor having a known transfer function and generating oxygen sensor output signals indicative of the output parameter of interest, the improvement in the system comprising:

a computing device connected to the oxygen sensor for receiving a plurality of said oxygen sensor output signals from the oxygen sensor at predetermined intervals of time, for processing said plurality of output signals, and for determining an estimate of said output parameter of interest based upon said oxygen sensor output signals and said known transfer function; and

means for outputting an indication of the estimate of said output parameter of interest.

2. In a method for determining a dynamically changing parameter of interest by providing an oxygen sensor exhibiting a dynamic characteristic having a time constant, resulting in a transient performance of the sensor, said oxygen sensor having a known transfer function for determining the output parameter of interest, the improvement in the method comprising the steps of:

receiving oxygen sensor output signals from said oxygen sensor;

determining an estimation of said output parameter of interest based upon said known transfer function and a plurality of said oxygen sensor output signals at predetermined intervals of time; and

outputting an indication of the estimation of said output parameter of interest.

3. A system for determining a dynamically changing output parameter of interest within a patient ventilation system, the system comprising:

an oxygen sensor exhibiting a dynamic characteristic having a time constant, resulting in a transient performance of the oxygen sensor, said oxygen sensor generating oxygen sensor output signals and having a known transfer function for determining the output parameter of interest;

computing means connected to said oxygen sensor for receiving a plurality of said oxygen sensor output signals at predetermined intervals of time, for processing said plurality of oxygen sensor output signals, and for determining an estimate of said output parameter of interest based upon said oxygen sensor output signals and said known transfer function; and

means for outputting an indication of said estimate of said output parameter of interest.

4. A method for determining a dynamically changing output parameter of interest within a patient ventilation system, the method comprising the steps of:

providing an oxygen sensor exhibiting a dynamic characteristic having a time constant, resulting in a transient performance of the oxygen sensor, said oxygen sensor having a known transfer function;

generating oxygen sensor output signals from said oxygen sensor;

determining an estimation of said output parameter of interest based upon said known transfer function and a plurality of said oxygen sensor output signals at predetermined intervals of time; and

outputting an indication of said estimation of said output parameter of interest.

5. In a system for determining a dynamically changing output parameter of interest in a patient ventilation system, said patient ventilation system having a source of breathing gas and a ventilation flow path for delivering said breathing gas, comprising:

an oxygen sensor for generating oxygen sensor output signals for determining the output parameter of interest of said breathing gas in said ventilation flow path, said oxygen sensor exhibiting a dynamic characteristic having a time constant, resulting in a transient performance of the oxygen sensor, and said oxygen sensor having a known transfer function;

computing means connected to said oxygen sensor for receiving said oxygen sensor output signals at predetermined intervals of time, for processing a plurality of said oxygen sensor output signals, and for determining an estimate of said output parameter of interest of said

breathing gas in said ventilation flow path based upon said oxygen sensor output signals and said known transfer function; and

means for outputting an indication of said estimate of said output parameter of interest of said breathing gas in said ventilation flow path.

6. A method for determining a dynamically changing output parameter of interest in a patient ventilation system, the steps of the method comprising:

providing a ventilator having a source of breathing gas and a ventilation flow path for delivering said breathing gas;

providing an oxygen sensor exhibiting a dynamic characteristic having a time constant, resulting in a transient performance of the oxygen sensor, said oxygen sensor generating oxygen sensor output signals and having a known transfer function for determining the output parameter of the breathing gas in the ventilation flow path;

determining an estimation of said output parameter of interest of said breathing gas in said ventilation flow path based upon said oxygen sensor output signals and said known transfer function; and

outputting an indication of said estimation of said output parameter of interest of said breathing gas in said ventilation flow path.