Respiratory profile parameter determination method and apparatus

• US 6,179,784 B1
• Filed: 06/16/1999
• Issued: 01/30/2001
• Est. Priority Date: 11/03/1997
• Status: Expired due to Term

• Current Assignee: RIC INVESTMENTS LLC (Respironics Incorporated)
• Original Assignee: NTC Technology, Inc. (Dixtal Medical, Inc.)
• Inventors: Daniels, Rich H., DelFavero, John R., Jaffe, Michael B., Gunneson, Paul B., Feldman, Barry J., Wigforss, Eric P.
• Primary Examiner(s): O'Connor, Cary
• Assistant Examiner(s): ASTORINO, MICHAEL C
• Application Number:
  US09/334,778
• Time in Patent Office: 594 Days
• Field of Search: 600/529, 600/532, 600/534, 600/538, 128/200-2-2
• US Class Current: 600/538
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/083 Measuring rate of metabolism by using breath test, e.g. measuring rate of oxygen consumption
• CPC Class Codes: A61B 5/087 Measuring breath flow
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/021 operated by electrical means A61M16/202 – A61M16/205 take precedence
• CPC Class Codes: A61M 2016/0036 in the breathing tube and used in both inspiratory and expiratory phase
• CPC Class Codes: A61M 2230/202 partial carbon oxide pressure, e.g. partial dioxide pressure (P-CO2)

Abstract

A method of sampling one or more respiratory profile characteristics and monitoring a variety of respiratory profile parameters. The sampled respiratory characteristics include respiratory flow rate, respiratory pressure, and partial pressure of at least one constituent of a patient'"'"'s respiration. The method detects patient breaths, determines whether each breath, is a spontaneous breath or a ventilator-induced breath, and calculates various respiratory profile parameters based on the sampled measurements. The method displays the respiratory profile parameters in graphic and numeric forms. Preferably, the method allows a user to select the displayed respiratory profile parameters.

Claims

1. A computer system for determining a plurality of respiratory profile characteristics, comprising:

a data component for generating data representative of a measured respiratory flow;

a logic circuit for detecting at least one patient breath based on said respiratory flow data;

a logic circuit for converting a plurality of measured respiratory flow data from a time domain to a volume domain to determine a plurality of respiratory volume parameters;

a logic circuit for determining a plurality of respiratory pressure parameters based at least in part on said respiratory flow data in said volume domain;

a logic circuit for determining at least one respiratory mechanics parameter based on at least one of said plurality of respiratory volume parameters and at least one of said plurality of respiratory pressure parameters.

2. The computer system according to claim 1, wherein said logic circuit for detecting at least one patient breath comprises:

a logic circuit for analyzing said plurality of respiratory pressure parameters and a plurality of respiratory volume data;

a logic circuit for comparing said respiratory pressure parameters to an inspiratory pressure threshold and an expiratory pressure threshold; and

a logic circuit for comparing said respiratory volume data to an inspiratory volume threshold and an expiratory volume threshold.

3. The computer system of claim 1, wherein said at least one respiratory mechanics parameter comprises dynamic compliance (C_dyn), static compliance (C_st), airway resistance during inspiration, airway resistance during expiration, compliance over the last twenty percent of a patient breath (C₂₀), C₂₀/C_dyn, ventilator work of breathing, or respiratory shallow breathing index.

4. A system for determining a plurality of respiratory profile characteristics, comprising:

a flow measurement component for measuring a respiratory flow of a patient;

a data component for generating data representative of said measured respiratory flow;

a logic circuit for detecting at least one patient breath based on said respiratory flow data;

a logic circuit for converting said respiratory flow data from a time domain to a volume domain to calculate a plurality of respiratory volume parameters;

a logic circuit for calculating a plurality of respiratory pressure parameters based at least in part on said respiratory flow data in said volume domain; and

a logic circuit for calculating at least one respiratory mechanics parameter based on at least one of said plurality of respiratory volume parameters and at least one of said plurality of respiratory pressure parameters.

5. The system of claim 4, wherein said logic circuit for detecting at least one patient breath comprises:

a logic circuit for analyzing said plurality of respiratory data; and

a logic circuit for comparing said respiratory flow profile characteristics to an inspiratory flow threshold and an expiratory flow threshold.

6. The system of claim 4, further comprising a logic circuit for characterizing said at least one patient breath as either a spontaneous breath or as a ventilator-induced breath.

7. The system of claim 6, wherein said logic circuit for characterizing said at least one patient breath compares selected ones of said plurality of respiratory pressure parameters to each other.

8. The system of claim 7, wherein said logic circuit for characterizing said at least one patient breath compares selected ones of said plurality of respiratory pressure parameters.

9. The system of claim 8, wherein said logic circuit for characterizing said at least one patient breath compares a mean inspiratory pressure of said at least one patient breath and a positive end-expiratory pressure of said at least one patient breath.

10. The system of claim 9, wherein, if said mean inspiratory pressure is less than or equal to said positive end-expiratory pressure, said at least one patient breath is characterized as a spontaneous breath.

11. The system of claim 8, wherein said logic circuit for characterizing said at least one patient breath compares a peak inspiratory pressure of said at least one patient breath and a positive end-expiratory pressure of said at least one patient breath.

12. The system of claim 11, wherein, if said peak inspiratory pressure is less than said positive end-expiratory pressure, said at least one patient breath is characterized as a spontaneous breath.

13. The system of claim 4, further comprising a logic circuit for calculating a plurality of dead space parameters.

14. The system of claim 13, wherein at least one of said plurality of dead space parameters is selected from the group comprising airway dead space, alveolar dead space, anatomic dead space, and physiologic dead space.

15. The system of claim 4, wherein said at least one respiratory mechanics parameter is selected from the group comprising dynamic compliance (C_dyn), static compliance (C_st), airway resistance during inspiration, airway resistance during expiration, compliance over the last twenty percent of a patient breath (C₂₀), C₂₀/C_dyn, ventilator work of breathing, or respiratory shallow breathing index.