INDIRECT MEASUREMENT IN A TOTAL LIQUID VENTILATION SYSTEM

• US 20160271348A1
• Filed: 06/25/2014
• Published: 09/22/2016
• 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, Robert, Raymond, Avoine, Olivier, Micheau, Philippe, Walti, Herve, Praud, Jean-Paul
• Granted Patent: US 10,661,037 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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, comprising:

a) obtaining at least one parameter measurement of a liquid taken in the TLV system comprising a tube having a distal end inserted in a patient'"'"'s respiratory tract;

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

c) processing, considering a fluid model of the TLV system, the at least one parameter measurement and the least one flow measurement into the indirect measurement of the parameter in the patient.

2. The method of claim 1, wherein obtaining the at least one parameter measurement comprises:

obtaining at least one pressure measurement of the liquid taken in the TLV; and

wherein processing the at least one measurement and the least one flow measurement into the indirect measurement of the parameter in the lung comprises;

processing the at least one pressure measurement into a pressure drop value within the TLV system considering the fluid model of the TLV system; and

processing the at least one pressure measurement and the pressure drop value into the indirect measurement of the parameter in the patient'"'"'s lung.

3. The method of claim 1 or claim 2 further comprising repeating steps a) to c) periodically.

4. The method of any one of claims 1 to 3 further comprising repeating steps a) to c) in real-time.

5. The method of any one of claims 1 to 4 wherein obtaining at least one measurement is performed by receiving data in a plurality of data packets over a network interface.

6. The method of any one of claims 2 to 5 further comprising periodically storing at least the indirect airway pressure value and optionally the pressure measurement, the flow measurement and the pressure drop value into memory.

7. The method of any one of claims 2 to 6 further comprising obtaining a variation of the flow of the liquid, wherein processing the flow measurement into a pressure drop value within the endotracheal tube is performed further considering the variation of the flow of the liquid.

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

9. The method of any one of claims 2 to 8, further comprising reading the fluid model of the TLV system from memory.

10. The method of any one of claims 2 to 9, 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.

11. The method of any one of claims 2 to 10, further comprising controlling a pump of the TLV system based at least on the indirect airway pressure value.

12. The method of any one of claims 1 to 5, wherein obtaining the at least one parameter measurement comprises obtaining at least one temperature measurement of a liquid expelled from the lung via the tube and wherein the fluid model of the TLV system is a thermodynamic model of the TLV system to estimate the thermal time constant in the TLV system based on flow value.

13. The method of claim 12, wherein obtaining the temperature measurement of the liquid is performed following a pause after an expiratory cycle of the patient.

14. The method of claim 12 or claim 13 wherein processing the at least one parameter measurement and the least one flow measurement into the indirect measurement of the parameter in the patient comprises:

processing more than one of the at least one flow measurement into flow rate integration to determine a time delay caused by thermal dead volume; and

processing the at least one temperature measurement considering the time delay the thermal time constant from the TLV model based on the at least one flow measurement.

15. The method of any one of claims 12 to 14, wherein the indirect measurement of the parameter in the patient indicates temperature of the patient'"'"'s lung, of the patient'"'"'s blood and/or of another of the patient'"'"'s organ.

16. The method of any one of claims 12 to 15, wherein the temperature of the liquid is measured at a junction of the tube to expiratory and inspiratory circuits of the TLV system.

17. The method of any one of claims 12 to 16, further comprising controlling a treatment unit of the TLV system based at least on the indirect temperature measurement.

18. An analyzer for determining an indirect measurement of a parameter in a patient with a total liquid ventilation (TLV) system, comprising:

a measurement interface module for;

a) obtaining at least one parameter measurement of a liquid taken in the TLV system comprising a tube having a distal end inserted in a patient'"'"'s trachea; and

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

a processor module for;

c) considering a fluid model of the TLV system, processing the at least one parameter measurement and the least one flow measurement into the indirect measurement of the parameter in the patient.

19. The analyzer of claim 18, wherein the measurement interface module obtains at least one parameter measurement by:

obtaining at least one pressure measurement of the liquid taken in the TLV; and

wherein the processor module, when processing the at least one measurement and the least one flow measurement into the indirect measurement of the parameter in the lung, is further for;

processing the at least one pressure measurement into a pressure drop value within the TLV system considering the fluid model of the TLV system; and

processing the at least one pressure measurement and the pressure drop value into the indirect measurement of the parameter in the patient'"'"'s lung.

20. The analyzer of claim 18 or claim 19, wherein a), b) and c) are periodically repeated.

21. The analyzer of any one of claims 18 to 20, wherein a), b) and c) are performed in real-time.

22. The analyzer of any one of claims 18 to 21, wherein the measurement interface is a network interface, obtaining at least one measurement further comprising receiving data in a plurality of data packets thereover.

23. The analyzer of any one of claims 19 to 22 further comprising a memory module for periodically storing at least the indirect airway pressure value and optionally the pressure measurement, the flow measurement and the pressure drop value thereinto.

24. The analyzer of any one of claims 19 to 23, wherein the measurement interface is further for obtaining a variation of the flow of the liquid, wherein the processor module is further for processing the flow measurement into a pressure drop value within the endotracheal tube considering the variation of the flow of the liquid.

25. The analyzer of claim 24, wherein the measurement interface is a network interface, obtaining the variation of the flow of the liquid further comprising receiving data in a plurality of data packets thereover.

26. The analyzer of any one of claims 19 to 25, further comprise a table stored in a memory module, the table comprising the fluid model of the TLV system.

27. The analyzer of any one of claims 19 to 26, wherein the processor module is further for 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.

28. The analyzer of any one of claims 19 to 27, further comprising a pump controller module for controlling a pump of the TLV system based at least on the indirect airway pressure value.

29. The analyzer of any one of claims 18 to 22, wherein the measurement interface module obtains the at least one parameter measurement by:

obtaining at least one temperature measurement of a liquid expelled from the lung via the endotracheal tube and wherein the fluid model of the TLV system is a thermodynamic model of the TLV system to estimate the thermal time constant in the TLV system based on flow value.

30. The analyzer of claim 29, wherein the measurement interface module obtains the temperature measurement of the liquid following a pause after an expiratory cycle of the patient.

31. The analyzer of claim 29 or claim 30, wherein the processor module, when processing the at least one parameter measurement and the least one flow measurement into the indirect measurement of the parameter in the patient, is further for:

processing more than one of the at least one flow measurement into flow rate integration to determine a time delay caused by thermal dead volume; and

processing the at least one temperature measurement considering the time delay the thermal time constant from the TLV model based on the at least one flow measurement.

32. The analyzer of any one of claims 29 to 31, wherein the indirect measurement of the parameter in the patient indicates temperature of the patient'"'"'s lung, of the patient'"'"'s blood and/or of another of the patient'"'"'s organ.

33. The analyzer of any one of claims 29 to 32, wherein the temperature of the liquid is measured at a junction of the endotracheal tube to expiratory and inspiratory circuits of the TLV system.

34. The analyzer of any one of claims 29 to 33, further comprising a temperature controller module for controlling a treatment unit of the TLV system based at least on the indirect temperature measurement.

35. 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, comprising:

a) obtaining at least one pressure parameter measurement and at least one temperature parameter measurement of a liquid taken in the TLV system comprising a tube having a distal end inserted in a patient'"'"'s respiratory tract;

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

c) considering at least one fluid model of the TLV system, processing the at least one pressure parameter measurement, the at least one temperature parameter measurement and the least one flow measurement into the indirect measurement of the indirect measurement of the temperature parameter and the indirect measurement of the pressure parameter.

36. The method of claim 35, further comprising controlling a treatment unit of the TLV system based at least on the indirect temperature measurement.

37. The method of claim 35 or claim 36, further comprising controlling a pump of the TLV system based at least on the indirect pressure measurement.

38. 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, comprising:

a measurement interface module for

a) obtaining at least one pressure parameter measurement and at least one temperature parameter measurement of a liquid taken in the TLV system comprising a tube having a distal end inserted in a patient'"'"'s respiratory tract; and

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

a processor module for;

c) considering at least one fluid model of the TLV system, processing the at least one pressure parameter measurement, the at least one temperature parameter measurement and the least one flow measurement into the indirect measurement of the indirect measurement of the temperature parameter and the indirect measurement of the pressure parameter.

39. The analyzer of claim 38, further comprising a temperature controller module for controlling a treatment unit of the TLV system based at least on the indirect temperature measurement.

40. The analyzer of claim 38 or claim 39, further comprising a pump controller module for controlling a pump of the TLV system based at least on the indirect pressure measurement.

41. A connector, comprising:

a junction for connecting expiratory and inspiratory circuits of a total liquid ventilation (TLV) system to a proximal end of an endotracheal tube having a distal end insertable in a patient'"'"'s trachea;

a pressure sensor, located within the junction, for measuring a pressure of a liquid present in the endotracheal tube; and

an interface for outputting pressure measurements of the liquid.

42. The connector of claim 41, comprising a flow sensor, located within the junction, for measuring a flow of the liquid within the endotracheal tube.

43. A TLV system configured to receive pressure and flow measurements of the liquid from the connector of claim 41 or claim 42, the TLV system comprising an analyzer configured to:

estimate a pressure drop within the endotracheal tube as a function of the flow of the liquid and as a function of a fluid model of the endotracheal tube; and

calculate an indirect airway pressure of the patient as a function of the measured pressure at the proximal end of the endotracheal tube and as a function of the estimated pressure drop within the endotracheal tube.

44. A TLV system configured to receive pressure measurements of the liquid from the connector of claim 41 or claim 42, the TLV system comprising a flow sensor, for measuring a flow of the liquid entering or leaving the endotracheal tube and an analyzer configured to:

estimate a pressure drop within the endotracheal tube as a function of the flow of the liquid and as a function of a fluid model of the endotracheal tube; and

calculate an indirect airway pressure of the patient as a function of the measured pressure at the proximal end of the endotracheal tube and as a function of the estimated pressure drop within the endotracheal tube.

45. A connector, comprising:

a junction for connecting expiratory and inspiratory circuits of a total liquid ventilation (TLV) system to a proximal end of an endotracheal tube having a distal end insertable in a patient'"'"'s trachea;

a temperature sensor, located within the junction, for measuring a temperature of a liquid expelled from the patient'"'"'s lungs via the endotracheal tube; and

an interface for outputting temperature measurements of the liquid.

46. A TLV system configured to receive temperature measurements of the liquid from the connector of claim 45, the TLV system comprising an analyzer configured to:

detect the end of an expiratory cycle; and

determine an indirect lung temperature by selecting a temperature measurement of the liquid received upon detection of the end of the expiratory cycle.

47. A TLV system configured to receive temperature measurements of the liquid from the connector of claim 45, the TLV system comprising an analyzer configured to:

detect the end of a dead volume retrieved from the lung,

detect the end of an expiratory cycle; and

determine a lung temperature based on measurements of the liquid temperature obtained between the end of the dead volume and the end of the expiratory cycle.