Method and apparatus for predicting mortality in congestive heart failure patients

• US 6,454,707 B1
• Filed: 03/06/2000
• Issued: 09/24/2002
• Est. Priority Date: 03/08/1999
• Status: Expired due to Fees

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Samuel W. Casscells III
• Inventors: Siadaty, M. Said, Naghavi, Monteza, Casscells, Samuel W. III
• Primary Examiner(s): HINDENBURG, MAX F
• Application Number:
  US09/519,122
• Time in Patent Office: 932 Days
• Field of Search: 600/549, 600/587, 600/300
• US Class Current: 600/300
• 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 5/412 Detecting or monitoring sepsis
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy

Abstract

Methods of predicting mortality or imminent death in patients with congestive heart failure include detecting changes in the patient'"'"'s temperature and/or the detection of hypothermia. The invention also relates to devices and kits for implementation of these methods.

Claims

1. A method of monitoring a patient with congestive heart failure for prognosis of survival, which comprises:

(a) obtaining an initial body temperature which is not elevated above normal,

(b) obtaining subsequent body temperatures of the patient and determining whether the subsequent temperatures fit any of predetermined criteria showing a condition of congestive heart failure hypothermia.

2. The method of claim 1 in which upon detection of a temperature less than normal temperature, core body temperature is monitored in step (b).

3. The method of claim 1 further characterized in that the initial body temperature is cutaneous and obtained as a pattern of base line temperatures from a plurality of surface sites on the patient, and step (b) includes analyzing the subsequent temperatures to determine variation of heat distribution over the body, and further including the step of (c) outputting an alarm if said heat distribution over the body exceeds a predetermined pattern indicative of congestive heart failure hypothermia.

4. The method of claim 1 in which said predetermined criteria showing a condition of congestive heart failure hypothermia include any one or more of:

(i) a decrease in temperature of about 2°

F. or more from said initial temperature,

(ii) a decrease in temperature of 1°

F. or more within a 12 hour period,

(iii) a decrease in temperature of about 1°

F. or more over 24 hours if the patient'"'"'s mean temperature is at or below 96.5°

F.,

(iv) a decrease in mean temperature of two standard deviations below the patient'"'"'s mean temperature over the prior 24 hours.

5. A method of predicting time remaining to death absent intervention for a patient with congestive heart failure, which comprises:

(a) obtaining an initial body temperature which is not elevated above normal,

(b) obtaining subsequent body temperatures of the patient and determining whether the subsequent temperatures fit any of predetermined criteria showing a condition of congestive heart failure hypothermia, and if so,

(c) predicting time to death according to the formula;

6. A method of warning of imminent mortality in a patient suffering from congestive heart failure absent therapeutic intervention, comprising:

(a) sensing internal and/or external temperatures of a patient

(b) analyzing the temperatures to determine a data set conforming to a predefined condition signifying congestive heart failure hypothermia; and

(c) issuing an alarm reporting said condition.

7. A method of predicting imminent mortality in a patient suffering from congestive heart failure, comprising:

(a) determining an initial body temperature which is not in excess of 97°

F.,

(b) obtaining subsequent body temperatures of the patient and determining whether the subsequent temperatures fit any of a first set of predetermined criteria for a condition of developing congestive heart failure hypothermia, and if so,

(c) monitoring the patient under a second set of predetermined criteria for a developed condition of congestive heart failure hypothermia and determining whether the subsequent temperatures fit any of said second set of predetermined criteria, and if so;

(d) triggering an alarm for intensive therapy.

8. A method of predicting imminent mortality in a patient suffering from congestive heart failure, comprising:

(a) determining an initial body temperature which is not in excess of 97°

F.,

(b) obtaining at least one temperature sensor for measuring a cutaneous body temperature and at least one sensor for measuring a core body temperature;

(c) positioning said sensors to be in direct contact with a patient having said initial temperature;

(d) transmitting said core body temperature and said cutaneous body temperature at predetermined timed intervals to a processor programmed to analyze said temperatures;

(e) analyzing said core body temperature and said cutaneous body temperature to determine if said temperatures fall outside of a predetermined criteria for a decrease in the patient'"'"'s temperature signifying a condition of congestive heart failure hypothermia; and

(f) triggering an alarm if said temperatures fall outside of said predetermined criteria.

9. The method of claim 8 in which said predetermined criteria in step (e) comprise at least one of:

(i) a decrease in temperature of about 2°

F. or more from said initial temperature,

(ii) a decrease in temperature of 1°

F. or more within a 12 hour period,

(iii) a decrease in temperature of about 1°

F. or more over 24 hours if the patient'"'"'s mean temperature is at or below 96.5°

F.,

(iv) a decrease in mean temperature of two standard deviations below the patient'"'"'s mean temperature over the prior 24 hours.

10. Apparatus for monitoring a patient with congestive heart failure for prognosis of survival, comprising:

(a) a temperature detector for sensing temperature of a patient and generating a signal representative of the sensed temperature

(b) a mount of said temperature sensor for indwelling or external placement on the patient,

(c) a data recorder for receiving said detector signals at timed intervals and using the signals to produce and store data representing temperatures of the patient sensed over time,

(d) an analyzer for processing said stored data to determine a data set conforming to a predefined condition signifying congestive heart failure hypothermia and outputting a signal indicative of the condition, and

(e) an alarm for receiving and reporting said output signal indicative of said condition.

11. The apparatus of claim 10 in which said predefined condition signifying congestive heart failure hypothermia is any one or more of:

(i) a decrease in temperature of about 2°

F. or more from said initial temperature,

(ii) a decrease in temperature of 1°

F. or more within a 12 hour period,

(iii) a decrease in temperature of about 1°

F. or more over 24 hours if the patient'"'"'s mean temperature is at or below 96.5°

F.,

(iv) a decrease in mean temperature of two standard deviations below the patient'"'"'s mean temperature over the prior 24 hours.

12. The apparatus of claim 10 in which said mount is an indwelling medical device selected from the group consisting of a needle, tube, catheter, line, pacemaker, implanted pump and implanted defibrillator.

13. The apparatus of claim 12, wherein said tube is selected from the group consisting of a nasogastric tube, Dubbhoff tube, endotracheal tube, rectal tube, T-tubes, drain, and nasal probe.

14. The apparatus of claim 12, wherein said catheter is selected from the group consisting of a urinary catheter, pulmonary artery catheter, triple-lumen catheter, dialysis catheter, Hickman catheter, and infusion catheter.

15. The apparatus of claim 10, wherein said mount for external placement is selected from the group consisting of umbilical sensor, skin electrode, tempanic ear sensor, pulse oximeter, and casts.

16. The apparatus of claim 10 in which said temperature detector is selected from the group consisting of a thermocouple, thermistor, thermosensitive chromophore, thermosensitive liquid crystal, infrared detector and ultrasound detector.

17. The apparatus of claim 10 further including means providing one or more additional predictors including one or more of O₂ saturation, P_ACO₂, pH, respiratory rate, QRS width, R—

R variability and T wave alternans, heart rate, blood pressure, pulse pressure and dP/dt, as a composite index to maximize sensitivity and specificity.

18. Apparatus comprising:

(1) means for monitoring a patient with congestive heart failure for prognosis of survival, including;

(a) a temperature detector for sensing temperature of a patient and generating a signal representative of the sensed temperature

(b) a mount of said temperature sensor for indwelling or external placement on the patient,

(c) a data recorder for receiving said detector signals at timed intervals and using the signals to produce and store data representing temperatures of the patient sensed over time,

(d) an analyzer for processing said stored data to determine a data set conforming to a predefined condition signifying congestive heart failure hypothermia and outputting a signal indicative of the condition, and

(e) an alarm for receiving and reporting said output signal indicative of said condition; and

(2) means of furnishing therapeutic warming to the patient.

19. A temperature monitoring kit for identifying a patient at risk of imminent death due to congestive heart failure, the kit comprising:

(a) at least one device for measuring a core temperature of a patient;

(b) at least one device for measuring a cutaneous temperature of the patient;

(c) means for transmitting the temperature measurements taken by said core temperature measuring device and said cutaneous temperature measuring device;

(d) means for analyzing the transmitted temperature measurements; and

(e) an alarm for reporting a dangerous decline in temperature in said patient.

20. The temperature monitoring kit of claim 19, wherein said core temperature measuring device includes a temperature detecting means attached to an indwelling or attached medical device.

21. The temperature monitoring kit of claim 19, wherein said cutaneous measuring device is selected from the group of umbilical sensor, skin electrode, and tympanic ear sensor.

22. The temperature monitoring kit of claim 19, wherein said analyzing means includes a processor programmed to identify when the temperature measurement transmitted to the analyzing means fall outside of a predetermined criteria.

23. The temperature monitoring kit of claim 22, wherein said predetermined criteria include any one of:

(i) a decrease in temperature of about 2°

F. or more from said initial temperature,

(ii) a decrease in temperature of 1°

F. or more within a 12 hour period,

(iii) a decrease in temperature of about 1°

F. or more over 24 hours if the patient'"'"'s mean temperature is at or below 96.5°

F.,

(iv) a decrease in mean temperature of two standard deviations below the patient'"'"'s mean temperature over the prior 24 hours.

24. The temperature monitoring kit of claim 19 wherein the alarm notifies a person of a change in the patient'"'"'s temperature, said notification including a text display, noise, shock, change in color or shape, warmth, or vibration.

25. The temperature monitoring kit of claim 19 further including means providing one or more additional predictors including one or more of O₂ saturation, P_ACO₂, pH, respiratory rate, QRS width, R—

R variability and T wave alternans, heart rate, blood pressure, pulse pressure and dP/dt, as a composite index to maximize sensitivity and specificity.

26. A temperature monitoring kit for identifying a patient at risk of imminent death due to congestive heart failure, the kit comprising:

(a) at least one device for measuring a core temperature of a patient, wherein said core temperature measuring device includes a temperature detecting means attached to an indwelling or attached medical device;

(b) at least one device for measuring a cutaneous temperature of the patient, wherein said cutaneous measuring device is selected from the group of an umbilical sensor, skin electrode, and tympanic ear sensor;

(c) means for transmitting the temperature measurements taken by said core temperature measuring device and said cutaneous temperature measuring device;

(d) means for analyzing the transmitted temperature measurements, wherein said analyzing means includes a processor programmed to identify when the temperature measurement transmitted to the analyzing means has decreased about 1°

F. or greater within a 12 hour period, about 2°

F. or greater over a 24 hour period, or about 1°

F. or greater if the patient'"'"'s baseline temperature is at or below 96.5°

F. or two standard deviations below the patient'"'"'s mean temperature for the prior 24 hours; and

(e) an alarm for reporting a dangerous decline in temperature in said patient, wherein the alarm notifies a person of a change in the patient'"'"'s temperature, said notification including a text display, noise, shock, change in color or shape, warmth, or vibration.

27. A device for analyzing temperature measurements comprising a processor programmed to activate an alarm if a core body temperature of a patient suffering from congestive heart failure and exhibiting a hypothermic baseline temperature of 97°

F. or less has

(i) a decrease in temperature of about 2°

F. or more from said initial temperature,

(ii) a decrease in temperature of 1°

F. or more within a 12 hour period,

(iii) a decrease in temperature of about 1°

F. or more over 24 hours if the patient'"'"'s mean temperature is at or below 96.5°

F.,

(iv) a decrease in mean temperature of two standard deviations below the patient'"'"'s mean temperature over the prior 24 hours.

28. A device for analyzing temperature measurements comprising a processor programmed to activate an alarm if a temperature gradient between a core body temperature and a surface body temperature exceeds a predetermined criteria determined to signify congestive heart failure hypothermia.

29. Apparatus for providing alarm of imminent mortality in a patient suffering from congestive heart failure, comprising means for initially and subsequently obtaining body temperatures of a patient of 97°

F. and lower and determining whether the subsequent temperatures lower than 97°

F. fit any of a first set of predetermined criteria for a condition of developing congestive heart failure hypothermia, and if so, monitoring the patient under a second set of predetermined criteria for a developed condition of congestive heart failure hypothermia and determining whether the subsequent temperatures fit any of said second set of predetermined criteria, and if so, triggering an alarm for intensive therapy.

30. A temperature sensor comprising a temperature measuring device, said measuring device having means for notifying a patient diagnosed with congestive heart failure when the patient'"'"'s temperature decreases below any one or more of predetermined criteria evidencing a condition of congestive heart failure hypothermia.

31. The temperature sensor of claim 30, wherein said sensor is attached to the patient'"'"'s wristwatch, clothing, or clothing accessories.