AUTOMATIC PHYSIOLOGICAL RECORDING AND ALARM SYSTEM FOR HOSPITALS

• US 3,646,930 A
• Filed: 11/03/1969
• Issued: 03/07/1972
• Est. Priority Date: 11/03/1969
• Status: Expired due to Term

• Current Assignee: John L. Walker Sr, Robert E. Patterson
• Original Assignee: John L. Walker Sr, Robert E. Patterson
• Inventors: Patterson, Robert E., Walker, John L. Sr.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US04/873,564
• Time in Patent Office: 855 Days
• Field of Search: 128/2.5P,2.5Q,2.5R,2.5S,2.5T,2.6A,2.6E,2.6F,2.6G,2.6R,2.1A
• US Class Current: 600/517
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/333 Recording apparatus specially adapted therefor
• CPC Class Codes: A61B 5/339 Displays specially adapted therefor
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia

Abstract

An EKG monitoring system for hospitals employing bedside units each connected by a simple two-wire cable to a remote central monitor having a chart recorder. A monitor signal, frequency modulated by an EKG signal, is produced by each unit and is carried over the cable to the central monitor. When the repetition rate of the R wave of a patient'"'"''"'"'s EKG signal rises above or falls below a predetermined safe range of repetition rates, or the R wave amplitude decreases to less than a predetermined minimum amplitude, an alarm oscillator in the unit is triggered and its output is multiplexed with the monitor signal, the alarm and monitor signals being different in frequency. The central monitor is frequency discriminatory and responds to the alarm signal to activate the chart recorder and feed the monitor signal thereto from the unit at the bedside of the ailing patient.

Claims

1. A physiological monitoring system comprising:

a plurality of sensing units each adapted to be operably associated with a living organism, each of said units being provided with an output connection, means responsive to the organism for providing a low frequency physiological information signal having a characteristic indicative of the condition of the organism, means for providing a carrier signal having a high frequency relative to said information signal and modulating said carrier signal with said information signal to produce an electrical monitor signal for delivery to said output connection, and means for producing a violation signal of a relatively high frequency different than said carrier signal frequency if said characteristic indicates that the condition of the organism is other than a predetermined, normal condition thereof, and for delivering said violation signal to said output connection whereby, when the violation signal is produced, a composite signal comprising the monitor and violation signals is presented at said output connection;

a central monitor remote from said units; and

electrical cable means for transmitting said monitor and composite signals from said units to said central monitor, said cable means comprising a plurality of transmission line conductors, each of which extends from the output connection of a corresponding unit to said central monitor for transmitting thereto the monitor signal or the composiTe signal produced by the unit, whereby the same conductor is employed to carry either the monitor or the composite signal produced by an individual unit, said central monitor having means for processing an incoming signal from said units to retrieve the information signal thereon, readout means responsive to the retrieved information signal, and frequency responsive control means coupled with said readout means and normally maintaining the latter in a standby state, said control means being responsive exclusively to the frequency of said violation signals, and said control means activating said readout means in response to the violation signal of an incoming composite signal from any of said units and effecting delivery of the incoming composite signal to said processing means, whereby the readout means responds exclusively to the information signal whose characteristic is in violation of the predetermined, normal organism condition.

2. The system as claimed in claim 1, each of said units having readout means at the unit location electrically independent of the readout means of said central monitor and operable to display the characteristic of the monitor signal produced by the unit.

3. The system as claimed in claim 1, said information signal of each unit being an EKG signal having a periodically recurring R wave constituting said characteristic, said predetermined, normal organism condition corresponding to a repetition rate of the R wave within a predetermined range of repetition rates, whereby said violation signal is produced by an individual unit if the R wave repetition rate is above or below said range.

4. The system as claimed in claim 1, said information signal of each unit being an EKG signal having a periodically recurring R wave constituting said characteristic, said predetermined, normal organism condition corresponding to an amplitude of the R wave above a predetermined minimum level, whereby said violation signal is produced by an individual unit if the R wave amplitude is below said level.

5. The system as claimed in claim 1, said control means having switching means for coupling the transmission line conductor from the output connection of any of said units to said processing means, and frequency selective means coupled with all of said transmission line conductors and responsive to the violation signal of said incoming composite signal for operating said switching means to connect said processing means with the conductor from the unit where the violation is occurring.

6. The system as claimed in claim 5, said central monitor being provided with indicating means responsive to the violation signal of said incoming composite signal for identifying the unit where the violation is occurring.

7. The system as claimed in claim 5, said information signal of each unit being an EKG signal having a periodically recurring R wave constituting said characteristic, said violation signal producing means of each unit including an oscillator for generating the violation signal, and means responsive to said EKG signal for activating said oscillator if the repetition rate of the R wave is above or below a predetermined range of repetition rates corresponding to said predetermined, normal organism condition.

8. The system as claimed in claim 7, said oscillator activating means of each unit being provided with a multivibrator for producing an output pulse in response to the occurrence of each R wave, an integrator responsive to said pulses and having an output level dependent upon the pulse frequency, and level sensing means responsive to the integrator output for triggering said oscillator to effect said activation thereof if the output level of the integrator falls below or rises above minimum or maximum levels, respectively, corresponding to the limits of said predetermined range of repetition rates.

9. The system as claimed in claim 8, saiD oscillator activating means of each unit being further provided with a threshold detector ahead of the multivibrator for receiving the EKG signal and passing the R wave thereof to the multivibrator if the amplitude of the R wave is above a predetermined minimum amplitude thereof corresponding to said predetermined, normal organism condition.

10. The system as claimed in claim 5, said monitor signal producing means of each unit including a frequency modulated oscillator having a modulating signal input, said information signal providing means deriving an EKG signal from the organism and applying the EKG signal to said input, said processing means having a frequency modulation discriminator for demodulating the monitor signal of the incoming composite signal fed thereto upon said operation of said switching means.