Method and system utilizing a disposable transmitter for monitoring a patient's condition

• US 3,921,621 A
• Filed: 08/23/1973
• Issued: 11/25/1975
• Est. Priority Date: 08/23/1973
• Status: Expired due to Term

• Current Assignee: Greenamyer Engineering and Technology Incorporated
• Original Assignee: Lee R. Baessler
• Inventors: Baessler, Lee R.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/390,759
• Time in Patent Office: 824 Days
• Field of Search: 128/2H,2R,2S,2.5R,2.6S,2.1A,2.1R 73/340-342,359-361,362R,362CP,362AR,362SC 324/181,186,78D 340/179,182,183,188CH,227R,228F,228R
• US Class Current: 600/549
• CPC Class Codes: A61B 2560/0412 Low-profile patch shaped housings
• CPC Class Codes: A61B 5/0008 Temperature signals
• CPC Class Codes: A61B 5/7445 Display arrangements, e.g. multiple display units
• CPC Class Codes: Y10S 128/903 Radio telemetry

Abstract

A method and system for monitoring a physical condition of a patient employing a radio frequency communications link between a disposable transmitter carried by the patient and a display unit. The display unit may be portable and include a receiving antenna. In other embodiments, the receiving antenna may be associated with the bed of the patient and the condition monitored by the electrical connection of a portable display unit thereto. In other embodiments, the receiving antenna associated with the bed of the patient may be wired to a remote console.

Claims

1. A system for monitoring the body temperature of a plurality of patients comprising:

a plurality of solid state electromagnetic wave energy transmitters each adapted to be carried by the body of a patient whose body temperature is to be monitored;

means for modulating the duty cycle of the electromagnetic wave energy transmitted to each of the solid state transmitters as a function of the body temperature of the patient by which the transmitter is carried;

a plurality of antennae each located in physical proximity to one of the patients to receive the modulated electromagnetic wave energy transmitted from the one of said plurality of transmitters carried by that patient, each of said antennae being connected to a plug; and

, a portable monitor having means selectively connected to the plug of one of said plurality of receiving antennae to monitor the duty cycle of the received electromagnetic wave energy to thereby monitor the body temperature of a selected one of the patient, said monitor means including;

means for detecting the duration of a cycle;

means for detecting the duty cycle of the detected cycle;

phase locked loop means for providing a digital signal variable in pulse repetition rate in response to said cycle duration detecting means to provide a predetermined number of pulses within the duration of the detected cycle; and

, means responsive to said duty cycle means and to said digital signal for manifesting the value of the sensed condition, said means including;

a bi-directional counter for counting in one direction responsively to the pulses occurring in said digital signal during the duty portion of a cycle of the received signal and for counting in the other direction during the remainder of the same cycle;

storage means; and

, a control pulse generator for effecting the transfer of the count in said bi-directional counter to said storage means and for effecting the resetting of said bi-directional counter at the end of each cycle.

2. The system of claim 1 wherein each of said plurality of receiving antennae comprises a flexible loop antenna disposable between the mattress of the patient'"'"''"'"'s bed and the bedding therefor without discomfort to the patient.

3. The system of claim 1 wherein each of said plurality of transmitters includes a source of direct current adapted to be secured to the body of a patient;

a solid state electromagnetic wave energy transmitting device adapted to be independently secured to the body of a patient and flexibly connected to said direct current source; and

, a temperature responsive element connected to said transmitting device to modulate duty cycle of the the transmitted electromagnetic wave energy as a function of the temperature of the patient.

4. The system of claim 3 wherein said transmitter comprises:

a first astable multivibrator responsive in duty cycle to the condition sensed; and

, a second astable multivibrator having a frequency at least one thousand times greater than the frequency of said first astable multivibrator, said second astable multivibrator being enabled responsively to said first astable multivibrator.

5. The transmitter of claim 4 wherein the timing elements of said first astable multivibrator are disposed in heat transmitting relationship to each other whereby distortion in the response of the duty cycle of said first astable multivibrator to the sensed condition due to ambient temperature is significantly reduced.

6. A system for monitoring the body temperature of a plurality of patients comprising:

a plurality of solid state electromagnetic wave energy transmitters each adapted to be carried by the body of a patient whose body temperature is to be monitored;

means for modulating the duty cycle of the electromagnetic wave energy transmitted by each of said solid state transmitters as a function of the body temperature of the patient by which the transmItter is carried; and

, a portable monitor including a receiving antenna for receiving a signal modulated by a signal variable in cycle duration and duty cycle, the antenna of said portable receiver being selectively positioned in proximity to a selected one of said plurality of transmitters to monitor the body temperature of a selected one of the patient, said monitor including;

means for detecting the duration of a cycle of the received signal;

means for detecting the duty cycle of the detected cycle;

means for providing a digital signal variable in pulse repetition rate in response to said cycle duration of the detected cycle; and

means responsive to said duty cycle detecting means and to said digital signal for manifesting the value of the sensed condition.

7. The system of claim 6 wherein the antenna of said portable monitor is a rod antenna connected to said portable monitor by a flexible electrical connector.

8. The system of claim 6 wherein each of said plurality of transmitters includes a source of direct current adapted to be secured to the body of a patient;

a solid state electromagnetic wave energy transmitting device adapted to be independently secured to the body of a patient and flexibly connected to said direct current source; and

, a temperature responsive element connected to said transmitting device to modulate the transmitted electromagnetic wave energy as a function of the temperature of the patient.

9. The system of claim 8 wherein each of transmitting devices includes:

a first astable multivibrator responsive in duty cycle to said temperature responsive element; and

, a second astable multivibrator having a frequency at least one thousand times greater than frequency of said first astable multivibrator and operatively connected thereto, said second astable multivibrator being enabled responsively to said first astable multivibrator.