GB2183123A

GB2183123A - Patient monitoring system

Info

Publication number: GB2183123A
Application number: GB08516085A
Authority: GB
Inventors: Martin Brevitt Coates
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-06-25
Filing date: 1985-06-25
Publication date: 1987-05-28
Also published as: GB8516085D0

Abstract

A patient monitoring system comprising two parts, a microphone P and radio transmitter T associated with the patient and a receiver R carried by the medical attendant, by which mean the actual heart beats and breath sounds can be monitored through an earphone E. The system allows for a variety of monitoring purposes, and allows complete mobility of the medical attendant within approximately a 150 metre radius. The system has a built in "fail-safe" in that any cause of inability of the medical attendant to hear the expected heart or breath sounds alerts the attendant to return instantly to the patient. <IMAGE>

Description

SPECIFICATION Patient Monitoring System This invention relates to a patient monitoring system of the kind which enables vital functions of a patient to be monitored remotely via a radio link.

Telemetry systems for the remote monitoring of the medical condition of a patient are very well known and widely used. Such systems are, however, generally complex and expensive, and designed to operate over a long range, either by a radio or line link. Moreover, the monitoring equipment is not mobile or readily portable.

Although the measurement of certain functions such as electrocardiogram, pulse rate, blood pressure and respiratory activity are important aids to monitor the condition of a patient, there are certain situations in which direct "sounding" of a patient's heart and lungs, as provided by a stethoscope, is more immediately indicative of the patient's condition than measurements of certain monitored functions. A case in point is where a patient is in a state of anaesthesia during a surgical operation, or in pre-operative or post-operative conditions. It is accepted practice under such conditions for the anaesthetist responsible for the patient to leave the patient temporarily in the charge of an assistant or nurse, for example to attend to problems elsewhere.If the anaesthetist can be provided with a continuous "sounding" of the patient's heart and lungs this will generally give the anaesthetist the essential information he needs to supervise the condition of the patient and to detect any impeding emergency condition. An object of the present invention is to provide a patient monitoring system which enables remote monitoring of a patient for such purposes as that mentioned above to be performed simply, and without recourse to complex or expensive monitoring and telemetry equipment.

According to the present invention there is provided a patient monitoring system comprising a transmitter unit connected to a pick-up for the direct audio monitoring of the heart and respiratory functions of a patient, and arranged to transmit a radio signal modulated by these functions, and a radio receiver unit for receiving and demodulating the radio signal to provide in an earpiece, loudspeaker or other audio transducer audible reproduction of the heart and respiratory functions.

The transmitter unit would normally be of short range, typically about 150 m, so that the system would be effective, for example, within the confines of a hospital. The receiver unit, and preferably also the transmitter unit, is preferably a personally portable unit, for example pocket-sized. The receiver unit would normally be carried by a medical supervisor, for example an anaesthetist, who would have an earpiece connected to the receiver unit through which he listens continuously to the monitored heart and respiratory functions of the patient.

The receiver unit may be provided additionally with an alarm device which provides an audible andi or visual alarm in the event of failure to detect the transmitted signal.

The invention will be further described, by way of example only, with reference to the accompanying purely diagrammatic drawing, which illustrates schematically a patient monitoring system according to one embodiment of the invention.

The illustrated patient monitoring system comprises a transmitter unit T and a receiver unit R both of which are personally portable batterypowered units of pocket size, preferably utilising rechargeable batteries.

The transmitter unit T includes a short range (approximately 150 m) radio transmitter and a modulator capable of modulating the transmitted radio signal with signals detected by an audio pickup P. The pick-up P may be an adapted stethoscope or microphone which is arranged to be placed upon the patient's thoraxor within the oesophagus to monitor continuously the heart and respiratory sounds of the patient. The transmitter unitT includes a simple audio amplifier and modulator stage and has in addition a small loudspeaker to provide a local audible output as and when required.

The audio signals picked up by the pick-up Pare used to modulate the radio signal transmitted by the transmitter unit T, these signals being picked up by the receiver unit R, in which they are demodulated.

The demodulated audio signal is passed directly, through a suitable amplifier, to an audio transducer E, for example an earpiece or headphone, or small loudspeaker, which reproduces directly the sound monitored by the pick-up P.

The system as described can be made extremely simply and inexpensively, given the short range requirement and the absence of any measuring instruments. Such a system has many practical applications. In the medical field, the system is particularly useful as an aid to anaesthetists. During the pre-operative, operative and post-operative stages an anaesthetist can monitor the actual heart and respiratory sounds of an anaesthetised patient, even if he has temporarily to leave the patient's side.

It is accepted in modern anaesthetic practice that the most reliable qualitative monitor of an anaesthetised patient's cardio-respiratory function is a simple pre-cordial (or oesophageal) stethoscope through which the anaesthetist, normally positioned by the head of the patient, listens to the patient's actual heart beats and breathing.

The simple patient monitoring system of the present invention enables an anaesthetist to maintain his monitoring of the heart beat and breathing of an anaesthetised patient even if he has to leave the normal position by the head of the patient. Any dangerous condition such as cardiac arrest, respiratory arrest or obstruction will be heard directly by the anaesthetist through the earphones E of the receiver unit. Similarly, if the audible signal hexa rid by the anaesthetist ceases for any other reason, such as, for exaple, battery failure or malfunction of any component of the system, the anaesthetist can return immediately to the patient.

The receiver unit may in fact be fitted with an audibleand/orvisual alarm which is triggered immediately the receiver unit fails to pick-up a signal from the transmitter unit.

Since the anaesthetist is provided with a direct "sounding" of the patient's actual heart beat and breathing he can also receive an instant alert of an impending problem or minor perturbations of cardiac or respiratory function, for example ectopic beats, sighs and hiccoughs, which can be precursors of more serious probiems.

Further applications of the monitoring system according to the invention in the field of cardiorespiratory monitoring are, for example, the following: (a) as a continuous monitor of the heart beat and breathing of a baby to provide an alarm in the event of failure of breathing and/or heart beat for any reason. This could provide a warning of an impending cot-death syndrome (S.l.D.S.).

(b) as a convenient monitor, free of cable connections, for the intensive care of patients following a period in intensive care unit, for example after weaning from ventilators.

(c) as a means of monitoring patient heart and breathing in an accident and emergency department or in an ambulance-for example when dealing with unconscious patients or patients who have suffered a heart attack and (d) as a means of monitoring the condition of a patient in a post-operative recovery room, and (e) as a means of direct communication, using the microphone component of the pick-up Ptotransmit verbal information from an attendant or nurse to an anaesthetist or physician at a remote location.

Claims

1. A patient monitoring system comprising two parts, a transmitter and a receiver, which enables the medical attendant to continuously hear the actual heart beats and breath sounds within an approximate 150 metre radius. The transmitter is attached to the patient and the receiver is attached to the medical attendant.

2. A patient monitoring system as in Claim 1, enabling the medical attendant to be fully mobile within a 150 metre radius and unattached to the patient.

3. A patient monitoring system as in Claims 1 and 2, independent of environmental considerations and requiring no structural alterations to the environment in which it is to be used.

4. A patient monitoring system as in Claims 1,2 and 3, primarily for use in anaesthesia, but with potential roles in pre and post-operative monitoring, ambulance transport monitoring, intensive care monitoring, and at-home monitoring of patients with potential cardio-respiratory malfunctions.