Method for controlling the temperature of an incubator

• US 5,385,529 A
• Filed: 09/29/1993
• Issued: 01/31/1995
• Est. Priority Date: 02/08/1991
• Status: Expired due to Term

• Current Assignee: Draeger Medical GmbH (Draegerwerk AG & Co KGaA)
• Original Assignee: Dragerwerk AG
• Inventors: Koch, Jochim
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): LACYK, JOHN P
• Application Number:
  US08/128,869
• Time in Patent Office: 489 Days
• Field of Search: 600/21-22, 128/736
• US Class Current: 600/22
• CPC Class Codes: A61G 11/00 Baby-incubators; Couveuses
• CPC Class Codes: A61G 2203/46 for temperature

Abstract

A method of controlling the operating parameters of an apparatus for maintaining the temperature of prematures and newborns is improved in that the operating parameters are determined based on a precise definition of the thermal condition of the patient and that information as to the bodily well-being based on determined sensor actual values for controlling the operating parameters are applied. For solving this task, the control takes place basically with the aid of at least two temperature sensors which measure the core temperature and the peripheral temperature, respectively, of the patient. The logic combination of the temperature signals takes place in such a manner that, in addition to the absolute temperature of one of the two sensors, the temperature difference between the two temperature sensors is simultaneously applied. In this way, it is possible for the first time that the thermal well-being of the patient is applied for controlling the incubator parameters and not only a single temperature.

Claims

1. A method for controlling an operating parameter of an apparatus for maintaining the temperature of a patient, the apparatus including heater means responsive to an actuating variable for adjusting the operating parameter in said apparatus, the method comprising the steps of:

applying a first temperature sensor to the body of the patient at a first location thereon to provide a first actual value representative of the core temperature of the patient;

applying a second temperature sensor to the body of the patient at a second location thereon remote from said first location to provide a second actual value representative of the periphery of the patient;

supplying said actual temperature values to a measured value processing unit;

determining the actual difference Δ

T_act value between said actual temperature values;

applying first and second desired temperature values and a desired difference Δ

T_des value of said desired temperature values to said measured value processing unit with said first and second desired temperature values and said desired difference Δ

T_des value being determined specific to the patient by medical personnel attending the patient;

logically combining said actual temperature values and said desired temperature values and said actual difference Δ

T_act value and said desired difference Δ

T_des value in said measured value processing unit in accordance with a preprogrammed algorithm to obtain a logic signal dependent upon said values; and

,

applying said logic signal to a controller for generating said actuating variable for controlling said operating parameter via said heater means for maintaining the temperature of the patient.

2. The method of claim 1, wherein the apparatus is an incubator defining an interior to which said heater means supplies heat;

and, wherein the method comprises the further steps of;

interrupting the heat supplied to said interior when said first actual value of temperature exceeds a first upper limit value; and

,

when said first actual value of temperature drops below a lower limit value and when said difference Δ

T_act is present which is equal to or less than said difference Δ

T_des, resuming or continuing the supply of heat to said interior in a controlled manner.

3. The method of claim 1, wherein the apparatus is an incubator defining an interior to which heat is supplied by said heater means;

and, wherein the method comprises the further steps of;

interrupting the supply of heat to said apparatus when the actual value of one of said sensors exceeds an upper limit value; and

,

when said first actual value of temperature drops below a lower limit value and when said second actual value of temperature is within a pregiven temperature range, resuming or continuing said supply of heat.

4. A method for controlling an operating parameter of an apparatus for maintaining the temperature of a patient, the apparatus including heater means responsive to an actuating variable for adjusting the operating parameter in said apparatus, the method comprising the steps of:

applying a first temperature sensor to the body of the patient at a first location thereon to provide a first actual value representative of the core temperature of the patient;

applying a second temperature sensor to the body of the patient at a second location thereon remote from said first location to provide a second actual value representative of the periphery of the patient;

supplying said actual temperature values to a measured value processing unit;

determining the temperature value of said second temperature sensor and comparing said temperature value to predetermined temperature limits above and below which the temperature of the patient should not move to obtain a comparison signal value;

applying said comparison signal value and said temperature value of said first and said second temperature sensors to said measured value processing unit in accordance with a preprogrammed algorithm to obtain a logic signal dependent upon said values; and

,

applying said logic signal to a controller for generating said actuating variable for controlling said operating parameter via said heater means to maintain said temperature value of said first temperature sensor and/or said second temperature sensor within said predetermined limits.

5. The method of claim 4, wherein the apparatus is an incubator defining an interior to which heat is supplied by said heater means;

and, wherein the method comprises the further steps of;

interrupting the supply of heat to said apparatus when the actual value of one of said sensors exceeds an upper limit value; and

,

when said first actual value of temperature drops below a lower limit value and when said second actual value of temperature is within a pregiven temperature range, resuming or continuing said supply of heat.

6. A method for controlling an operating parameter of an apparatus for maintaining the temperature of a patient, the apparatus including heater means responsive to an actuating variable for adjusting the operating parameter in said apparatus, the method comprising the steps of:

applying first and second temperature sensors to the body of the patient at two locations, respectively, thereon to obtain a first actual temperature value indicative of the core temperature of the patient and a second actual temperature value of a peripheral temperature of the patient;

supplying said actual temperature values to a measured value processing unit;

determining the actual difference Δ

T_act value between said actual temperature values;

applying a first desired temperature value corresponding to the desired core temperature of the patient and a second desired temperature value corresponding to the desired peripheral temperature of the patient as well as a desired difference Δ

T_des value of said desired temperature values to said measured value processing unit with said first and second desired temperature values and said desired difference Δ

T_des value being determined specific to the patient by medical personnel attending the patient;

logically combining said actual and desired temperature values and said actual difference Δ

T_act value and said desired difference Δ

T_des value in said measured value processing unit in accordance with a preprogrammed algorithm and;

(a) determining if said first actual temperature value is greater than said first desired temperature value and, if so, then issuing a fever alarm and interrupting heating via said heating means, and if not,

(b) determining if said actual difference Δ

T_act value is equal to or greater than said desired difference Δ

T_des value and, if so, then interrupting heating via said heating means; and

, if not,

(c) determining if said actual difference Δ

T_act value has increased and said first actual temperature is within its predetermined temperature range and, if so, then issuing a shock alarm and maintaining heating on via said heater means, and if not, also maintaining heating on via said heater means without issuing said shock alarm.