Indirect measurement in a total liquid ventilation system

• US 10,661,037 B2
• Filed: 06/25/2014
• Issued: 05/26/2020
• Est. Priority Date: 06/25/2013
• Status: Active Grant

• Current Assignee: Socpra Sciences Et Gnie S.E.C.
• Original Assignee: Socpra Sciences Et Gnie S.E.C.
• Inventors: Nadeau, Mathieu, Micheau, Philippe, Robert, Raymond, Walti, Herve, Avoine, Olivier, Praud, Jean-Paul
• Primary Examiner(s): Yu, Justine R
• Assistant Examiner(s): Moon, Matthew R
• Application Number:
  US15/023,290
• Publication Number:
  US 20160271348A1
• Time in Patent Office: 2,162 Days
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/087 Measuring breath flow
• CPC Class Codes: A61F 7/0053 Cabins, rooms, chairs or units for treatment with a hot or cold circulating fluid
• CPC Class Codes: A61F 7/12 Devices for heating or cooling internal body cavities
• CPC Class Codes: A61M 16/0003 Accessories therefor, e.g. sensors, vibrators, negative pressure
• CPC Class Codes: A61M 16/0054 Liquid ventilation
• CPC Class Codes: A61M 16/0069 the speed thereof being controlled by respiratory parameters, e.g. by inhalation
• 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 16/04 Tracheal tubes catheters in general A61M25/00
• CPC Class Codes: A61M 16/0816 Joints or connectors
• CPC Class Codes: A61M 16/0833 T- or Y-type connectors, e.g. Y-piece
• CPC Class Codes: A61M 16/109 the humidifying liquid or the beneficial agent
• CPC Class Codes: A61M 16/14 by mixing different fluids, one of them being in a liquid phase
• CPC Class Codes: A61M 16/201 Controlled valves
• CPC Class Codes: A61M 19/00 Local anaesthesia syringes therefor A61M5/00; Hypothermia A61M5/42 takes precedence; cooling blood in a bypass of the arterial system A61M1/36
• CPC Class Codes: A61M 2016/0018 electrical
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/003 with a flowmeter
• CPC Class Codes: A61M 2016/0036 in the breathing tube and used in both inspiratory and expiratory phase
• CPC Class Codes: A61M 2205/3334 : Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/3358 : Measuring barometric pressure, e.g. for compensation
• CPC Class Codes: A61M 2205/3368 : Temperature
• CPC Class Codes: A61M 2205/3592 : using telemetric means, e.g. radio or optical transmission
• CPC Class Codes: A61M 2205/3606 : cooled
• CPC Class Codes: A61M 2205/366 : by liquid heat exchangers
• CPC Class Codes: A61M 2205/52 : with memories providing a history of measured variating parameters of apparatus or patient
• CPC Class Codes: A61M 2205/583 : by visual feedback
• CPC Class Codes: A61M 2205/702 : automatically during use
• CPC Class Codes: A61M 2230/50 : Temperature

Abstract

A method, connector and system for obtaining an indirect measurement of a parameter in a patient with a total liquid ventilation (TLV) system. At least one parameter measurement is obtained of a liquid taken in the TLV system comprising an endotracheal tube having a distal end inserted in a patient'"'"'s trachea. At least one flow measurement is obtained of a liquid taken in the TLV system. Considering a fluid model of the TLV system, the at least one parameter measurement and the least one flow measurement are processed into the indirect measurement of the parameter in the patient. The indirect measurement may be a temperature or pressure. The temperature can be a lung temperature, a blood temperature or an organ temperature. The pressure may be a tracheal pressure or an alveolar pressure.

Claims

1. A method for determining an indirect measurement of a parameter in a patient with a total liquid ventilation (TLV) system, the TLV system comprising a tube having a distal end adapted to be inserted in a respiratory tract of the patient, the method comprising:

a) obtaining at least one parameter measurement of a liquid taken in the TLV system from at least one first sensor

b) obtaining at least one flow measurement of the liquid taken in the TLV system from a second sensor;

c) determining a fluid model of the TLV system based at least in part on one or both of the at least one parameter measurement of the liquid and the at least one flow measurement of the liquid; and

d) determining the indirect measurement of the parameter in the patient by processing, considering the fluid model of the TLV system, the at least one parameter measurement and the at least one flow measurement,

wherein the indirect measurement of the parameter in the patient is an indirect airway pressure value, the at least one first sensor includes a pressure sensor and the at least one parameter measurement of the liquid taken in the TLV system includes at least one pressure measurement, and wherein processing the at least one parameter measurement and the at least one flow measurement to determine the indirect measurement of the at least one parameter in the patient comprises;

processing the at least one flow measurement to estimate a pressure drop value within the TLV system considering the fluid model of the TLV system,

determining the indirect airway pressure value in the patient by processing the at least one pressure measurement and the pressure drop value, and

controlling a pump of the TLV system based at least on the indirect airway pressure value.

2. The method of claim 1 further comprising repeating steps a) to d) periodically.

3. The method of claim 1 further comprising repeating steps a) to d) in real-time.

4. The method of claim 1 wherein obtaining the at least one parameter measurement is performed by receiving data in a plurality of data packets from the at least one first sensor over a network interface.

5. The method of claim 1 further comprising periodically storing at least the indirect airway pressure value.

6. The method of claim 1 further comprising obtaining a variation of a flow of the liquid, wherein processing the at least one flow measurement to estimate the pressure drop value within the TLV system is performed further considering the variation of the flow of the liquid.

7. The method of claim 6 wherein obtaining the variation of the flow of the liquid is performed by receiving data in a plurality of data packets from the second sensor over a network interface.

8. The method of any one of claims 1 and 5 to 7, further comprising reading the fluid model of the TLV system from memory.

9. The method of any one of claims 1 and 5 to 7, further comprising determining and/or updating the fluid model of TLV system by determining a resistance of the tube and an inertance of the liquid in the tube.

10. The method of any one of claims 1 and 5 to 7, wherein the at least one first sensor includes a temperature sensor, wherein obtaining the at least one parameter measurement comprises obtaining at least one temperature measurement from the temperature sensor of a liquid expelled from the patient'"'"'s respiratory tract via the tube, and wherein the fluid model of the TLV system is a thermodynamic model of the TLV system to estimate a thermal time constant in the TLV system based on the at least one flow measurement.

11. The method of claim 10, wherein obtaining the at least one temperature measurement of the liquid is performed following a pause after an expiratory cycle of the patient.

12. The method of claim 10, wherein processing the at least one parameter measurement and the at least one flow measurement to determine the indirect measurement of the parameter in the patient comprises:

processing at least two flow measurements into a flow rate integration to determine a time delay caused by thermal dead volume;

processing the at least one temperature measurement considering the thermal time constant estimated from the thermodynamic model of the TLV system based on the at least one flow measurement,

determining the thermal dead volume, and

integrating expiratory flow until the exhaled volume becomes greater than the thermal dead volume, where the resulting integration period is considered as the time delay caused by the thermal dead volume.

13. The method of claim 10, wherein the indirect measurement of the parameter in the patient is an indirect temperature measurement that indicates a temperature of the patient'"'"'s lung, of the patient'"'"'s blood and/or of another of the patient'"'"'s organ.

14. The method of claim 10, wherein the at least one temperature measurement of the liquid is measured at a junction of the tube to expiratory and inspiratory circuits of the TLV system.

15. The method of claim 13, further comprising controlling a treatment unit of the TLV system based at least on the indirect temperature measurement.

16. An analyzer for determining an indirect measurement of a parameter in a patient with a total liquid ventilation (TLV) system, the TLV system comprising a tube having a distal end adapted to be inserted in a patient'"'"'s respiratory tract, the analyzer comprising:

an interface configured to;

a) obtain at least one parameter measurement of a liquid taken in the TLV system from at least one first sensor; and

b) obtain at least one flow measurement of the liquid taken in the TLV system from a second sensor; and

a processor configured to;

c) determine a fluid model of the TLV system based at least in part on one or both of the at least one parameter measurement of the liquid and the at least one flow measurement of the liquid; and

d) determine the indirect measurement of the parameter in the patient by processing, considering the fluid model of the TLV system, the at least one parameter measurement and the at least one flow measurement,

wherein the indirect measurement of the parameter in the patient is an indirect airway pressure value, the at least one first sensor includes a pressure sensor and the at least one parameter measurement of the liquid in the TLV system includes at least one pressure measurement, and

wherein the processor when processing the at least one parameter measurement and the at least one flow measurement to determine the indirect measurement of the parameter in the patient, is further configured to;

process the at least one flow measurement to estimate a pressure drop value within the TLV system considering the fluid model of the TLV system,

determine the indirect airway pressure value in the patient by processing the at least one pressure measurement and the pressure drop value, and

control a pump of the TLV system based at least on the indirect airway pressure value.

17. The analyzer of claim 16, wherein a), b), c), and d) are periodically repeated.

18. The analyzer of claim 16, wherein a), b), c), and d) are performed in real-time.

19. The analyzer of claim 16, wherein the interface is a network interface, and obtaining the at least one parameter measurement from the at least one first sensor further comprising receiving data in a plurality of data packets thereover.

20. The analyzer of claim 16, further comprising a memory module for periodically storing at least the indirect airway pressure value.

21. The analyzer of claim 16, wherein the interface is further configured to obtain a variation of a flow of the liquid, wherein the processor is further configured to process the at least one flow measurement to estimate the pressure drop value within the TLV system considering the variation of the flow of the liquid.

22. The analyzer of claim 21, wherein the interface is a network interface, and obtaining the variation of the flow of the liquid further comprising receiving data from the second sensor in a plurality of data packets thereover.

23. The analyzer of claim 16, further comprising a table stored in a memory module, the table comprising the fluid model of the TLV system.

24. The analyzer of claim 16, wherein the processor is further configured to determine and/or update the fluid model of TLV system by determining a resistance of the tube and an inertance of the liquid in the tube.

25. The analyzer of claim 16, wherein the at least one first sensor includes a temperature sensor, and the interface obtains the at least one parameter measurement by:

obtaining at least one temperature measurement from the temperature sensor of a liquid expelled from the patient'"'"'s respiratory tract via the tube, and wherein the fluid model of the TLV system is a thermodynamic model of the TLV system to estimate a thermal time constant in the TLV system based on the at least one flow measurement.

26. The analyzer of claim 16, wherein the interface obtains the at least one temperature measurement of the liquid following a pause after an expiratory cycle of the patient.

27. The analyzer of claim 16 or claim 25, wherein the processor, when processing the at least one parameter measurement and the at least one flow measurement to determine the indirect measurement of the parameter in the patient, is further configured to:

process at least two flow measurements into a flow rate integration to determine a time delay caused by thermal dead volume;

process the at least one temperature measurement considering the thermal time constant estimated from the thermodynamic model of the TLV system based on the at least one flow measurement;

determining the thermal dead volume, and

integrating expiratory flow until the exhaled volume becomes greater than the thermal dead volume, where the resulting integration period is considered as the time delay caused by the thermal dead volume.

28. The analyzer of claim 16 or claim 25, wherein the indirect measurement of the parameter in the patient is an indirect temperature measurement that indicates a temperature of the patient'"'"'s lung, of the patient'"'"'s blood and/or of another of the patient'"'"'s organ.

29. The analyzer of claim 16 or claim 25, wherein the at least one temperature measurement of the liquid is measured at a junction of the tube to expiratory and inspiratory circuits of the TLV system.

30. The analyzer of claim 27, wherein the processor is further configured to control a treatment unit of the TLV system based at least on the indirect temperature measurement.

31. A method for determining an indirect measurement of a temperature parameter and an indirect measurement of a pressure parameter in a patient with a total liquid ventilation (TLV) system, the TLV system comprising a tube having a distal end adapted to be inserted in a patient'"'"'s respiratory tract, the method comprising:

a) obtaining at least one pressure parameter measurement of a liquid taken in the TLV system from a pressure sensor and at least one temperature parameter measurement of the liquid taken in the TLV system from a temperature sensor;

b) obtaining at least one flow measurement of the liquid taken in the TLV system from a flow meter;

c) determining at least one fluid model of the TLV system based at least in part on one or more of the at least one pressure parameter measurement, the at least one temperature parameter measurement, and the at least one flow measurement of the liquid;

d) determining the indirect measurement of the temperature parameter and the indirect measurement of the pressure parameter in the patient by processing, considering the at least one fluid model of the TLV system, the at least one pressure parameter measurement, the at least one temperature parameter measurement, and the at least one flow measurement; and

e) controlling a pump of the TLV system based at least on the indirect measurement of the pressure parameter, wherein the indirect measurement of the pressure parameter corresponds to an indirect airway pressure value.

32. The method of claim 31, further comprising controlling a treatment unit of the TLV system based at least on the indirect measurement of the temperature parameter.

33. An analyzer for determining an indirect measurement of a temperature parameter and an indirect measurement of a pressure parameter in a patient with a total liquid ventilation (TLV) system, the TLV system comprising a tube having a distal end adapted to be inserted in a patient'"'"'s respiratory tract, the analyzer comprising:

an interface configured to;

a) obtain at least one pressure parameter measurement of a liquid taken in the TLV system from a pressure sensor and at least one temperature parameter measurement of the liquid taken in the TLV system from a temperature sensor; and

b) obtain at least one flow measurement of the liquid taken in the TLV system from a flow meter; and

a processor configured to;

c) determine at least one fluid model of the TLV system based at least in part on one or more of the at least one pressure parameter measurement, the at least one temperature parameter measurement, and the at least one flow measurement of the liquid;

d) determine the indirect measurement of the temperature parameter and the indirect measurement of the pressure parameter by processing, considering the at least one fluid model of the TLV system, the at least one pressure parameter measurement, the at least one temperature parameter measurement, and the at least one flow measurement; and

e) control a pump of the TLV system based at least on the indirect pressure measurement of the pressure parameter, wherein the indirect measurement of the pressure parameter corresponds to an indirect airway pressure value.

34. The analyzer of claim 33, wherein the processor is further configured to control a treatment unit of the TLV system based at least on the indirect measurement of the temperature parameter.