Method and Apparatus for Controlling the Inner Temperature of a Patient

• US 20160135987A1
• Filed: 06/03/2014
• Published: 05/19/2016
• Est. Priority Date: 06/04/2013
• Status: Active Grant

• Current Assignee: Vither Hyperthermia B.V. (Vithèr Holding BV)
• Original Assignee: Vither Hyperthermia B.V. (Vithèr Holding BV)
• Inventors: MIGNOT, Marcel Henri, BOTTEMA, Cornelis Watze, NIX, Robbert Renald Rudolf, VAN DOORN, Ronald Albertus Arnoldus
• Granted Patent: US 10,575,985 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2034/105 Modelling of the patient, e.g. for ligaments or bones
• CPC Class Codes: A61B 34/10 Computer-aided planning, simulation or modelling of surgical operations
• CPC Class Codes: A61F 2007/0054 with a closed fluid circuit, e.g. hot water
• CPC Class Codes: A61F 2007/0056 for cooling
• CPC Class Codes: A61F 2007/0069 with return means
• CPC Class Codes: A61F 2007/0086 with a thermostat
• CPC Class Codes: A61F 2007/0093 programmed
• CPC Class Codes: A61F 2007/0096 with a thermometer
• CPC Class Codes: A61F 2007/0288 during operations
• CPC Class Codes: A61F 2007/126 for invasive application, e.g. for introducing into blood vessels
• CPC Class Codes: A61F 7/0085 Devices for generating hot or cold treatment fluids
• CPC Class Codes: A61F 7/12 Devices for heating or cooling internal body cavities

Abstract

The invention relates to a method and apparatus for controlling the inner temperature of a patient, comprising the steps of creating a fluid circuit that comprises a patient and a heat exchanger, the power supply thereto being controlled by a controller; subjecting at least a portion of the fluid in said circuit to the heat exchanger; directing the subjected fluid to and into the patient to control the temperature of the patient; estimating the organ temperature of the patient by a model that has been obtained on a mammal other than the patient; and controlling the power supply to the heat exchanger such that the estimated organ temperature does not exceed a threshold organ temperature, potentially taking into account estimated future organ temperatures. The invention further relates to a method and apparatus for controlling the inner temperature of a patient when subject to whole body hyperthermia, and to a method for obtaining the model.

Claims

1-30. -30. (canceled)

31. Method for controlling the inner temperature of a patient, the method comprising the steps of:

creating a fluid circuit that comprises a patient and a heat exchanger, the power supply thereto being controlled by a controller;

subjecting at least a portion of the fluid in said circuit to the heat exchanger;

directing the subjected fluid to and into the patient to control the temperature of the patient;

estimating the temperature of an organ of the patient at a time t by a model comprising a parametric correlation function of the temperature of the organ and a number of input parameters, wherein the parametric correlation function, including the calibration of the parameters of the correlation function, has been obtained on a mammal other than the patient; and

controlling the power supply to the heat exchanger such that the estimated organ temperature remains below an upper threshold organ temperature and/or above a lower threshold organ temperature.

32. Method according to claim 31, wherein the patient is subject to whole body hyperthermia.

33. Method according to claim 31, wherein the input parameters comprise the temperature of at least one body part of the patient other than the organ, and the power supplied to the heat exchanger prior to time t, wherein the at least one body part comprises the bladder, the skin, left tympanic, right tympanic, anus, pulmonary arteries, femoral veins, and/or oesophagus.

34. Method according to claim 31, wherein the input parameters comprise the temperature of at least five body parts of the patient other than the skin.

35. Method according to claim 31, wherein the input parameters comprise the body mass of the patient.

36. Method according to claim 31, wherein the power supply to the heat exchanger is discontinued at a time t and the future organ temperature after time t is estimated from the power supplied to the heat exchanger prior to time t.

37. Method according to claim 31, wherein the organ temperature at a time t is estimated by deriving the organ temperature at time t for each input parameter, and taking the arithmetic mean of the derived organ temperatures for all input parameters to obtain the estimated organ temperature, wherein the arithmetic mean does not include the highest and the lowest value of the derived organ temperatures for each temperature measured.

38. Method according to claim 31, wherein the parametric correlation function for one temperature sensor “

i”

is given by;

T_organ(t)=C_i+f_skin·

T_skin+f_i·

Tⁱ_sensor1/MΣ

f_j·

P(Δ

t_j)

wherein

T_organ(t)=organ temperature at time t;

C_i=a parameter constant for sensor “

i”

(°

C.);

f_skin=a parameter constant (−

);

T_skin=the measured skin temperature (°

C.);

f_i=a parameter constant (−

) for the i_th temperature sensor;

Tⁱ_sensor=the measured temperature of the i_th temperature sensor (°

C.);

M=body mass of the mammal (kg);

Σ

f_j·

P(Δ

t_j)=a weighted sum of the heat outputs of the heat exchanger in time intervals Δ

t_j=t_j−

t_j-1 prior to time t with f_j=parameter constant for each j_th time interval.

39. Method according to claim 31, wherein the parametric correlation function for one temperature sensor “

i”

is given by;

T_organ(t)=C_i+f_i*Tⁱ_sensor1/M∫

f_j·

Q(t)·

(T_fin−

T_fout)dt

wherein

T_organ(t)=organ temperature at time t;

C_i=a parameter constant for sensor “

i”

(°

C.);

f_i=a parameter constant (−

) for the i_th temperature sensor;

Tⁱ_sensor=the measured temperature of the i_th temperature sensor (°

C.);

M=body mass of the mammal (kg);

∫

f_j·

Q(t)·

(T_fin−

T_fout)dt=the integral from t_j to t_j-1 of the product of the fluid flow Q (in m³/sec) and the temperature difference between the measured temperature T_fin of the fluid (°

C.) when entering the body and the measured temperature T_fout of the fluid (°

C.) when exiting the body in time intervals Δ

t_j=t_j−

t_j-1 prior to time t with f_j=parameter constant for each j_th time interval.

40. Method according to claim 31, wherein the parametric correlation function for one temperature sensor “

i”

is given by;

T_organ(t)=C_iT_estimate(0)+f_i·

(Tⁱ_sensor−

Tⁱ⁰_sensor)+1/MΣ

f_j·

P(Δ

t_j)

wherein

T_organ(t)=organ temperature at time t;

C_i=a parameter constant for sensor “

i”

(°

C.);

T_estimate(0) the estimated organ temperature at time 0;

f_i=a parameter constant (−

) for the i_th temperature sensor;

Tⁱ_sensor=the measured temperature of the i_th temperature sensor (°

C.);

Tⁱ⁰_sensor=the measured temperature of the i_th temperature sensor (°

C.) at time 0;

M=body mass of the mammal (kg);

Σ

f_j·

P(Δ

t_j)=a weighted sum of the heat outputs of the heat exchanger in time intervals Δ

t_j=t_j−

t_j-1 prior to time t with f_j=parameter constant for each j_th time interval.

41. Method for obtaining a model for estimating a patient'"'"'s organ temperature at a time t wherein the model is obtained on a mammal other than the patient and comprises a parametric correlation function of the organ temperature and a number of input parameters, the method comprising:

creating a fluid circuit that comprises a mammal and a heat exchanger, the power supply thereto being controlled by a controller;

controlling the heat exchanger to a set temperature profile;

subjecting at least a portion of the fluid in said circuit to the heat exchanger;

directing the subjected fluid to and into the mammal to change the temperature of the mammal;

measuring corresponding input parameters comprising the temperature of at least one body part of the mammal at a time t; and

the power supplied to the heat exchanger prior to time t;

measuring the organ temperature of the mammal at the time t;

establishing a parametric correlation function between an estimated organ temperature of the mammal and the input parameters measured on the mammal, and

determining the parameters of the parametric correlation function such that the difference between the estimated organ temperature calculated with the correlation function and the measured organ temperature is minimized.

42. Apparatus for controlling the inner temperature of a patient, the apparatus comprising:

at least one catheter for creating a fluid circuit external to the patient;

a pump in association with said catheter, for pumping a fluid through said fluid circuit and the patient;

a heat exchanger through said fluid circuit flows for influencing the temperature of said fluid;

a controller arranged to estimate an organ temperature of said patient and control the power supplied to the heat exchanger based on the estimated organ temperature, wherein the organ temperature is estimated by a model comprising a parametric correlation function of the temperature of the organ and a number of input parameters, wherein the parametric correlation function, including the calibration of the parameters of the correlation function, has been obtained on a mammal other than the patient.

43. Apparatus according to claim 42, comprising at least two temperature sensors for measuring the temperature of multiple body parts of the patient, wherein the controller is arranged to estimate the organ temperature by measuring input parameters comprising the temperature of the at least two temperature sensors, and the power supplied to the heat exchanger prior to time t.

44. Apparatus according to claim 42, comprising at least two temperature sensors for measuring the temperature of the patient on multiple locations on the body of the patient, means for measuring the flow rate of the fluid, as well as means for measuring the temperature of the fluid when entering and exiting the patient, wherein the controller is arranged to estimate the organ temperature by measuring input parameters comprising the temperature of the at least two temperature sensors, the fluid flow rate into the patient and the fluid temperatures entering and exiting the patient.

45. Apparatus according to claim 42, comprising at least two temperature sensors for measuring the temperature of the patient on multiple locations on the body of the patient, wherein the controller is arranged to estimate the organ temperature by measuring input parameters comprising the temperature of the at least two temperature sensors at time 0, and the estimated organ temperature at time 0.

46. Apparatus according to claim 42, wherein the heat exchanger is a heater and/or a cooler.

47. Apparatus according to claim 42, wherein the controller is arranged to estimate the organ temperature of the patient based on signals from the temperature sensors and controlling the power supply to the heat exchanger such that the estimated organ temperature remains below an upper threshold organ temperature and/or above a lower threshold organ temperature.

48. Apparatus according to claim 42, wherein the controller is arranged to measure the temperatures simultaneously.

49. Apparatus according to claim 42, wherein the input parameters comprise the body mass of the patient.

50. Apparatus according to claim 42, wherein the controller is arranged to discontinue the power supply to the heat exchanger at a time t and to estimate the future organ temperature after time t from the power supplied to the heat exchanger prior to time t.

51. Apparatus according to claim 42, wherein the controller is arranged to estimate the organ temperature at a time t by deriving the organ temperature at time t for each input parameter, and taking the arithmetic mean of the derived organ temperatures for all input parameters to obtain the estimated organ temperature, wherein the arithmetic mean does not include the highest and the lowest value of the derived organ temperatures for each temperature measured.

52. Apparatus according to claim 42, wherein the parametric correlation function for one temperature sensor “

i”

is given by;

T_organ(t)=C_i+f_skin·

T_skin+f_i·

Tⁱ_sensor1/MΣ

f_j·

P(Δ

t_j)

wherein

T_organ(t)=organ temperature at time t;

C_i=a parameter constant for sensor “

i”

(°

C.);

f_skin=a parameter constant (−

);

T_skin=the measured skin temperature (°

C.);

f_i=a parameter constant (−

) for the i_th temperature sensor;

Tⁱ_sensor=the measured temperature of the i_th temperature sensor (°

C.);

M=body mass of the patient (kg);

Σ

f_j·

P(Δ

t_j)=a weighted sum of the heat outputs of the heat exchanger in time intervals Δ

t_j=t_j−

t_j-1 prior to time t with f_j=parameter constant for each j_th time interval.

53. Apparatus according to claim 42, wherein the parametric correlation function for one temperature sensor “

i”

is given by;

T_organ(t)=C_i+f_i*Tⁱ_sensor1/M∫

f_j·

Q(t)·

(T_fin−

T_fout)dt

wherein

T_organ(t)=organ temperature at time t;

C_i=a parameter constant for sensor “

i”

(°

C.);

f_i=a parameter constant (−

) for the i_th temperature sensor;

Tⁱ_sensor=the measured temperature of the i_th temperature sensor (°

C.);

M=body mass of the patient (kg);

∫

f_j·

Q(t)·

(T_fin−

T_fout)dt=the integral from t_j to t_j-1 of the product of the fluid flow Q (in m³/sec) and the temperature difference between the measured temperature T_fin of the fluid (°

C.) when entering the body and the measured temperature T_fout of the fluid (°

C.) when exiting the body in time intervals Δ

t_j=t_j−

t_j-1 prior to time t with f_j=parameter constant for each j_th time interval.

54. Apparatus according to claim 42, wherein the parametric correlation function for one temperature sensor “

i”

is given by;

T_organ(t)=C_iT_estimate(0)+f_i·

(Tⁱ_sensor−

Tⁱ⁰_sensor)+1/MΣ

f_j·

P(Δ

t_j)

wherein

T_organ(t)=organ temperature at time t;

C_i=a parameter constant for sensor “

i”

(°

C.);

T_estimate(0)=the estimated organ temperature at time 0;

f_i=a parameter constant (−

) for the i_th temperature sensor;

Tⁱ_sensor=the measured temperature of the i_th temperature sensor;

Tⁱ⁰_sensor=the measured temperature of the i_th temperature sensor (°

C.) at time 0;

M=body mass of the patient (kg);

Σ

f_j·

P(Δ

t_j)=a weighted sum of the heat outputs of the heat exchanger in time intervals Δ

t_j=t_j−

t_j-1 prior to time t with f_j=parameter constant for each j_th time interval.