Electronic clincal thermometer

• US 5,259,389 A
• Filed: 03/08/1993
• Issued: 11/09/1993
• Est. Priority Date: 10/24/1990
• Status: Expired due to Term

• Current Assignee: Terumo Kabushiki Kaisha
• Original Assignee: Terumo Kabushiki Kaisha
• Inventors: Muramoto, Yutaka, Ikeda, Makoto, Toriumi, Makoto
• Primary Examiner(s): Pellegrino, Stephen C.
• Assistant Examiner(s): Tucker, Guy V.
• Application Number:
  US08/028,685
• Time in Patent Office: 246 Days
• Field of Search: 128/736, 128/664, 364/413.03, 364/557, 364/581, 364/551.01, 374/169, 374/170, 374/171, 374/102, 374/103, 374/104, 374/107
• US Class Current: 600/546
• CPC Class Codes: G01K 7/42 Circuits effecting compensation of thermal inertia; Circuits for predicting the stationary value of a temperature

Abstract

In a predicting-type electronic clinical thermometer, data acquired from a temperature sensor (51) at a very small time interval (Δt) is read in on a real-time basis, the data is converted into detected temperature (T) by means of a processor (9), the temperature is stored in a memory (7) and a temperature prediction is performed to obtain a predicted temperature (Tp). The rate of change (ΔT/Δt) in the detected temperature is obtained based upon the detected temperature (T). The moment at which this rate of change attains a predetermined value is taken as an opportunity to check the temporal fluctuation of the predicted temperature within a fixed reference time range. If the predicted temperature is found to have stabilized, the temperature detection is terminated. If it has not stabilized, the temperature detection is continued. Thus, the process through which an allowable condition for a valid prediction was realized is investigated looking back a predetermined length of time from the moment at which the condition was realized, and the result of the investigation is applied when evaluating the validity of the prediction. As a result, a highly accurate temperature prediction can be performed even if the circumstances in which the thermometer is being used changes during temperature detection.

Claims

1. An electronic clinical thermometer for measuring body temperature of a given region of a body comprising:

temperature detecting means for measuring said body temperature of the region in a predetermined time interval;

memory means for storing a signal corresponding to said body temperature;

predicting means for predicting an equilibrium temperature based upon said body temperature measured by said temperature detecting means;

first calculating means for calculating a rate of change in said body temperature with time;

first comparing means for comparing said rate of change with a predetermined value;

time detecting means for detecting a time when said rate of change reaches said predetermined value, based on results of the comparison by said first comparing means;

second calculating means for calculating a rate of change in said predicted equilibrium temperature with time as a stability index of whether said predicted equilibrium temperature has stabilized within a predetermined time range in the time detected by said time detecting means which serves as a reference;

second comparing means for comparing said rate of change in said predicted equilibrium temperature calculated by said second calculating means with a predetermined comparison value in order to examine whether said predicted equilibrium temperature has stabilized;

display means for displaying said predicted equilibrium temperature obtained by said predicting means; and

control means for controlling the temperature measurement performed by said temperature detecting means in a manner such that when said predicted equilibrium temperature has stabilized, the temperature measurement is terminated, while when said predicted equilibrium temperature is still unstable, the temperature measurement is continued, based on results of the comparison performed by said second comparing means.

2. The thermometer according to claim 1, wherein said second calculating means includes:

means for obtaining a regression line of a time variation in the predicted equilibrium temperature; and

means for employing the slope of said regression line as the stability index.

3. The thermometer according to claim 1, wherein said second calculating means includes:

means for obtaining a regression line of a time variation in said predicted equilibrium temperature within a predetermined time range; and

means for employing an intercept of said regression line as the stability index.

4. The thermometer according to claim 1, wherein said second calculating means includes:

means for obtaining a value of the difference between a maximum value and a minimum value of said predicted equilibrium temperature, a value of the difference between the mean value of said predicted equilibrium temperature and the maximum value, or a value of the difference between the mean value of said predicted equilibrium temperature and the minimum value within said predetermined time range; and

means for employing an obtained value as the stability index.

5. The thermometer according to claim 1, wherein said second calculating means includes:

means for calculating a value, which is the result of integrating, with regard to a predetermined closed interval, of a curve indicative of a change in the prediction equilibrium value with time obtained from the time variation in said predicted equilibrium temperature within said predetermined time range; and

means for employing the calculated value as the stability index.