Event-Based Delay Detection And Control Of Networked Systems In Medical Ventilation

• US 20110209704A1
• Filed: 02/26/2010
• Published: 09/01/2011
• Est. Priority Date: 02/26/2010
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Inventors: Upham, Gail F., McCoy, Edward R., Jafari, Mehdi M., Jimenez, Rhomere S.
• Granted Patent: US 9,302,061 B2
• Time in Patent Office: Days
• US Class Current: 128/204.23
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/0063 Compressors
• CPC Class Codes: A61M 16/026 specially adapted for predicting, e.g. for determining an information representative of a flow limitation during a ventilation cycle by using a root square technique or a regression analysis
• CPC Class Codes: A61M 16/0833 T- or Y-type connectors, e.g. Y-piece
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0036 in the breathing tube and used in both inspiratory and expiratory phase
• CPC Class Codes: A61M 2205/35 Communication
• CPC Class Codes: A61M 2205/3507 with implanted devices, e.g. external control
• CPC Class Codes: A61M 2205/3561 local, e.g. within room or hospital
• CPC Class Codes: A61M 2205/3569 sublocal, e.g. between console and disposable
• CPC Class Codes: A61M 2205/505 Touch-screens; Virtual keyboard or keypads; Virtual buttons; Soft keys; Mouse touches
• CPC Class Codes: A61M 2230/005 Parameter used as control input for the apparatus

Abstract

This disclosure describes systems and methods for detecting and quantifying transmission delays associated with distributed sensing and monitoring functions within a ventilatory system. Specifically, the present methods and systems described herein define an event-based delay detection algorithm for determining transmission delays between distributed signal measurement and processing subsystems and a central platform that receives data from these subsystems. It is important to evaluate and quantify transmission delays because dyssynchrony in data communication may result in the misalignment of visualization and monitoring systems or instability in closed-loop control systems. Generally, embodiments described herein seek to quantify transmission delays by selecting a ventilator-based defining event as a temporal baseline and calculating the delay between the inception of the defining event and the receipt of data regarding the defining event from one or more distributed sensing devices.

Claims

1. A method for determining a transmission delay associated with a distributed sensor in a ventilatory system, the method comprising:

initiating a defining event;

receiving a plurality of data samples after inception of the defining event from an internal sensor and from a distributed sensor;

indexing the plurality of data samples in order of successive cycles based on data sample arrival times from the internal sensor and from the distributed sensor;

calculating a first number of cycles received from the internal sensor after inception of the defining event until a first data sample breaches a threshold;

calculating a second number of cycles received from the distributed sensor after inception of the defining event until a first data sample breaches the threshold;

calculating the transmission delay associated with the distributed sensor by subtracting the first number of cycles from the second number of cycles;

synchronizing data received from the internal sensor and the distributed sensor based on the calculated transmission delay associated with the distributed sensor; and

displaying the synchronized data.

2. The method of claim 1, wherein the defining event is a transition from inspiration to expiration.

3. The method of claim 1, wherein the plurality of data samples is 20 data samples collected over 100 milliseconds (ms) after the inception of the defining event by the internal sensor and 20 data samples collected over 100 milliseconds (ms) after the inception of the defining event by the distributed sensor.

4. The method of claim 1, wherein the distributed sensor is a proximal flow sensor.

5. The method of claim 1, wherein the threshold is a circuit pressure change of 0.5 cm H₂O, and wherein the threshold is breached when a data sample indicates that circuit pressure dropped by 0.5 cm H₂O or more.

6. The method of claim 1, further comprising:

initiating a plurality of consecutive defining events comprising a transition from inspiration to expiration for each of a plurality of consecutive breaths.

7. The method of claim 6, further comprising:

calculating a set of distributed sensor delays, wherein the set of distributed sensor delays comprises a distributed sensor delay for each of the plurality of consecutive defining events; and

calculating a median of the set of distributed sensor delays to yield a distributed sensor delay coefficient.

8. The method of claim 7, further comprising:

synchronizing the data received from the internal sensor and the distributed sensor based on the distributed sensor delay coefficient.

9. A ventilatory system for determining a transmission delay associated with a distributed sensor in a ventilatory system, comprising:

at least one processor; and

at least one memory, communicatively coupled to the at least one processor and containing instructions that, when executed by the at least one processor, perform a method comprising;

initiating a defining event;

receiving a plurality of data samples after inception of the defining event from an internal sensor and from a distributed sensor;

indexing the plurality of data samples in order of successive cycles of data sample arrival times from the internal sensor and from the distributed sensor;

calculating a first number of cycles received from the internal sensor after inception of the defining event until a first data sample breaches a threshold;

calculating a second number of cycles received from the distributed sensor after inception of the defining event until a first data sample breaches the threshold; and

calculating the transmission delay associated with the distributed sensor by subtracting the first number of cycles from the second number of cycles; and

synchronizing data received from the internal sensor and the distributed sensor based on the calculated transmission delay associated with the distributed sensor.

10. The ventilatory system of claim 9, wherein the defining event is a transition from inspiration to expiration.

11. The ventilatory system of claim 9, wherein the plurality of data samples is 20 data samples collected over 100 milliseconds (ms) after the inception of the defining event by the internal sensor and 20 data samples collected over 100 milliseconds (ms) after the inception of the defining event by the distributed sensor.

12. The ventilatory system of claim 9, wherein the distributed sensor is a proximal flow sensor.

13. The ventilatory system of claim 9, wherein the threshold is a circuit pressure change of 0.5 cm H₂O, and wherein the threshold is breached when a data sample indicates that circuit pressure dropped by 0.5 cm H₂O or more.

14. The ventilatory system of claim 9, further comprising at least one of;

displaying the synchronized data;

analyzing the synchronized data for making a recommendation regarding at least one of;

a patient condition and a patient treatment; and

analyzing the synchronized data for adjusting one or more ventilatory settings.

15. The ventilatory system of claim 9, further comprising:

initiating a plurality of consecutive defining events comprising a transition from inspiration to expiration for each of a plurality of consecutive breaths;

calculating a set of distributed sensor delays, wherein the set of distributed sensor delays comprises a distributed sensor delay for each of the plurality of consecutive defining events; and

calculating a median of the set of distributed sensor delays to yield a distributed sensor delay coefficient.

16. The ventilatory system of claim 15, further comprising:

synchronizing the data received from the internal sensor and the distributed sensor based on the distributed sensor delay coefficient.

17. A method for determining a transmission delay associated with a distributed sensor in a ventilatory system, the method comprising:

initiating a defining event;

receiving a plurality of data samples after inception of the defining event from an internal sensor and from a distributed sensor;

indexing the plurality of data samples in order of successive cycles based on data sample arrival times from the internal sensor and from the distributed sensor;

calculating a first number of cycles received from the internal sensor after inception of the defining event until a first data sample breaches a threshold;

calculating a second number of cycles received from the distributed sensor after inception of the defining event until a first data sample breaches the threshold;

calculating the transmission delay associated with the distributed sensor by subtracting the first number of cycles from the second number of cycles;

synchronizing data received from the internal sensor and the distributed sensor based on the calculated transmission delay associated with the distributed sensor; and

analyzing the synchronized data for making a recommendation regarding at least one of;

a patient condition and a patient treatment.

18. The method of claim 17, further comprising:

initiating a plurality of consecutive defining events comprising a transition from inspiration to expiration for each of a plurality of consecutive breaths.

19. The method of claim 18, further comprising:

calculating a set of distributed sensor delays, wherein the set of distributed sensor delays comprises a distributed sensor delay for each of the plurality of consecutive defining events; and

calculating a median of the set of distributed sensor delays to yield a distributed sensor delay coefficient.

20. The method of claim 19, further comprising:

synchronizing the data received from the internal sensor and the distributed sensor based on the distributed sensor delay coefficient.