WO2006077291A1

WO2006077291A1 - System for controlling and regulating oxygen flow

Info

Publication number: WO2006077291A1
Application number: PCT/FR2005/003178
Authority: WO
Inventors: Jean-Pierre Paris
Original assignee: Bear Medical Sas
Priority date: 2005-01-18
Filing date: 2005-12-16
Publication date: 2006-07-27
Also published as: FR2880810A1; FR2880810B1

Abstract

The invention relates to a system which is essentially characterised in that each displacement sensor module (4) comprises a pre-treatment card (4A) defining a plurality of levels of activity pre-established by the practician, and an emission/reception module (4B) transmitting the motive activities detected by the displacement sensors (4) to the microcontroller (7) in such a way as to intervene immediately and in anticipation, in terms of the oxygen requirements of the patient, and in that the oxymetry unit (5), associated with an infrared-type sensor placed on a finger or on the ear lobe of a patient, especially measures the oxygen flow in the blood and the cardiac frequency, which are both transmitted to the microcontroller (7).

Description

CONTROL SYSTEM AND CONTROL OF OXYGEN FLOW ¹

DESCRIPTION

The invention relates to a system for controlling and regulating the flow rate of oxygen adapted to the physiological needs of an oxygen-dependent patient.

Systems of this type generally consist of an autonomous unit carried by the patient and remote means able to communicate with said portable unit which essentially comprises: a) a standard medical oxygen cylinder equipped with a pressure reducer; b) an oxygen distribution unit provided with a regulating solenoid valve ensuring the controlled supply of oxygen in at least one nostril of the patient via a dispensing tube; c) at least one motion sensor, of the accelerometer type, defining the physical activity of the patient; d) an oximetry unit, associated with an infrared type sensor placed on a finger or the lobe of an ear of the patient, measuring blood oxygen level and heart rate; e) a sensor detecting the inspiration and expiration phases so as to allow the passage of oxygen through the control solenoid valve only during said inspiration phase; f) a central unit with:

a microcontroller processing the data coming from said sensors and controlling the oxygen flow rate of the regulating solenoid valve as a function of the values of said data relative to reference values relating to a specific patient and stored in said unit; ;

- a communication interface with a local or remote computer;

- a screen displaying the operating parameters of the system and patient data.

People with respiratory failure represent a significant part of the population.

For example, chronic obstructive pulmonary disease (COPD) is responsible for more than 15,000 deaths per year in France and affects nearly 2.5 million people, out of breath at the slightest effort.

This disease, too little known, too frequent, too deadly, too disabling, too neglected, is considered by specialists as a serious public health problem. Specific prevention and follow-up actions are currently carried out in France. They concern the optimization of the "doctor-patient" couple and the validation of a tool for remote monitoring of the quality of life of chronic respiratory patients who have been in a rehabilitation clinic. More broadly, 300,000 patients suffer from respiratory failure in France. Among them, 150,000 are heavy handicapped requiring hospitalization and the use of complex and voluminous breathing systems such as CPAP (Continuous Positive Airway Pressure) or VAC (Controlled Assisted Ventilation). According to major health insurance plans, each year 30,000 people are admitted to a long-term condition for severe chronic respiratory failure. This figure is up sharply from one year to the next, with a greater worsening for the female population. In Europe, there are more than 1.5 million patients. Today, all these patients use oxygen cylinders with manual control of the solenoid valve. Oxygen is continuously sent through a breathing telescope in a continuous manner.

Faced with the increase in the number of oxygen addicts and the daily difficulties they face (physiological, psychological, quality of life, autonomy), it became urgent to equip them with effective tools to improve their quality of life and care and their autonomy.

The known systems for said patients are essentially described in the following patents:

WO-9904841 which discloses a control device for supplying oxygen in response to a deficiency, with dosage control, for an oxygen dependent patient;

US-4584996 which describes a method and a device for intermittently administering oxygen to patients, programmed according to need and activity (by measuring the frequency of breathing cycles) with flow control (by means of a valve); US-5928189 which describes a system intended to intervene therapeutically on the human body, in response to the activity of a person and more particularly to his oxygen needs; the system in question implements various detectors (including accelerometers) and a control circuit of a valve regulating the flow of oxygen; - FR-2835188, of the same applicant, which describes a system which detects the motor activities of the patient to anticipate his oxygen needs with immediate action on the flow of oxygen and which measures the oxygen level in the blood of the patient with action delayed on the flow of oxygen. This method has the advantages, in immediate action mode, of avoiding a sudden under oxygenation which can lead to loss of consciousness and, in delayed action mode, of verifying the good functioning of the whole by a measurement of the real oxygenation, to correct changes during the day of the pathological state of the patient and gradually reduce the flow of oxygen when all activity has stopped (saving oxygen but especially limiting the risk of burning mucous membranes).

The flow rate of oxygen is thus controlled and regulated to adapt it to the physiological needs of the patients so as to satisfy all the desired improvements and to allow greater autonomy and a reduction in the weight of the bottles.

The present invention proposes to go even further in improving the system for increased treatment efficiency, for better patient management and for effective overall management of the "patient-doctor" couple. It is essentially characterized in that: a) each motion sensor module, which is of the tri-axis accelerometer type, comprises a pretreatment card defining several levels of activities pre-established by the practitioner and each corresponding to a specific need for oxygen and a transmission / reception module transmitting to the microcontroller the motor activities detected by the motion sensors so as to intervene, immediately and in anticipation, on the patient's oxygen requirements by acting on the oxygen flow of the control valve , proportional type, after a time of the order of a few thousandths of a second; (b) the oximetry unit, which is associated with an infrared-type sensor placed on a finger or lobe of a patient's ear, measures the level of oxygen in the blood and heart rate that is transmitted to the patient microcontroller so as to intervene, delayed, on oxygen flow rates of the proportional type control valve, associated with the classified activity levels in order to regulate the oxygen saturation as close as possible to the threshold setpoint of regulation predefined by the practitioner, after a time of the order of a few seconds, these new values being assigned to the main means of regulation. It is also characterized in that the central unit comprises means for: a- recording, for several tens of days, information relating to:

- to the patient such as the accumulated use time of the system, the oxygen consumed, the actual physical activity, the heart rate, the oxygen level in the blood, the warnings due to a bad breathing, the variation of the flow of oxygen based on the actual activity level of the patient to meet the practitioner's prescriptions, alarms, and device control parameters;

- the system, such as the level of the battery, the level of oxygen remaining in the bottle, the disconnection of one of the sensors; b- viewing said information on a local screen; c- sending said information to the practitioner's computer, instantaneously or deferred;

3) to send the data relating to the patient and the system, to a database belonging to a home remote monitoring network of the patient and viewable by the practitioner.

The features and advantages of the invention will appear more clearly on reading the detailed description which follows of at least one preferred embodiment thereof given by way of non-limiting example and shown in the accompanying drawings.

On these drawings:

- Figure 1 is a schematic view of the system according to the invention; FIG. 2 is a block diagram of the general operation of the central unit;

- Figure 3 is a schematic view of the system according to the invention configured in a network.

The oxygen flow control and regulation system adapted to the physiological needs of the patient, represented in the figures, consists of an autonomous unit (UP) carried by the patient and remote means able to communicate with said portable unit which comprises essentially: a) a standard medical oxygen cylinder (1) equipped with a pressure reducer; b) an oxygen distribution unit provided with a regulating solenoid valve (2) ensuring the controlled supply of oxygen in at least one nostril of the patient via a dispensing tube (3); c) at least one motion sensor module (4), of the accelerometer type, defining the physical activity of the patient; d) an oximetry unit (5), associated with an infrared type sensor placed on a finger or the lobe of an ear of the patient, measuring the oxygen level in the blood and the heart rate; e) a sensor (6) detecting the inspiration and expiration phases so as to allow the passage of oxygen through the control solenoid valve only during said inspiration phase; f) a central unit with:

a microcontroller (7) processing the data coming from said sensors and controlling the oxygen flow rate of the regulating solenoid valve as a function of the values of said data relative to reference values relating to a well-determined patient and stored in memory; in said unit;

an interface (8) for communication with a local or remote computer (9);

a screen (10) displaying the operating parameters of the system and data relating to the patient. Each motion sensor module (4), which is of the accelerometer type, in particular triaxial, placed on the trunk of the patient, comprises a pre-treatment card (4A) defining several levels of activities pre-established by the practitioner and corresponding to each a very specific need for oxygen and a transmission / reception module (4B) transmitting to the microcontroller (7) the motor activities detected by the motion sensors (4) so as to intervene, immediately and in advance, on the needs of oxygen of the patient by acting on the oxygen flow of the regulating valve (2), the proportional type, after a time of the order of a few thousandths of a second, it also comprises a source of energy (4C ) ensuring the electric autonomy of the sensor;

The oximetry unit (5), which is associated with an infrared type sensor placed on a finger or on the lobe of a patient's ear, measures the oxygen level in the blood and / or the heart rate and in addition the blood glucose level and / or blood pressure which are transmitted to the microcontroller (7) so as to intervene, delayed, the oxygen flow rates of the proportional type control valve (2) associated with the classified activity levels in order to regulate oxygen saturation as close as possible to the preset regulation threshold set by the practitioner at the end of a time of the order of a few seconds, these new values being assigned to the main control means.

The distribution unit comprises, in addition to the regulation solenoid valve (2), a bypass solenoid valve (11), associated with a bypass circuit (12), allowing the direct flow of oxygen flow, either by manual action of the patient, either by action programmed by the central unit. The central unit (CPU) comprises:

GPS location means;

buttons (13) able to actuate the display, on the screen (10), the level of the battery (14), the level of oxygen remaining in the bottle, the patient's heart rate, the rate of oxygen in the patient's blood, the flow of oxygen supplied to the patient, the mode of the solenoid valve (automatic or manual), the type of bottle in use. The central unit (CU) also includes a means of: a) recording, for several tens of days, information relating to:

- the system, such as the level of the battery, the level of oxygen remaining in the bottle, the disconnection of one of the sensors; b) viewing said information on the screen (10); c) sending said information to the practitioner's computer. The central unit (CU) also comprises:

means for sending the data relating to the patient and the system to a database belonging to a home remote monitoring network of the patient and viewable by the practitioner;

a means for continuously performing the 6 minute test by providing the practitioner, at a close distance (less than 250 m), the curves of the respiratory cycle, the heart rate, the oxygen level in the blood as well as that all the patient's clinical data such as walking speed, distance traveled and distance of one step.

The system can comprise several portable units (UP) for oxygen flow control and regulation connected to at least one intermediate concentrator (Cl), local or remote, continuously managing patient data and alarms, itself connected to a concentrator Central (CC), local or remote, also continuously managing patient data and alarms as well as all intermediate hubs so as to switch from one intermediate hub to another depending on its availability. This configuration is ideally suited in hospitals but can be extended to any other environment.

The sensors for measuring the saturation rate of oxygen in the blood can be maintained by glasses. The same is true of the sensors intended to measure the inspiration phase of the patient and of the oxygen delivery tube in the nostril. of the patient. The central unit (CPU): a) receives the data from the sensors (CA) in order to control, after their treatment (TR), the regulation electrovalve (ER) and to automatically deliver the oxygen (OX) to the patient; b) data from the other parts of the device (software fault, wire torn, etc.) to control, after their treatment (TS), the bypass solenoid valve (ED) and allow the direct delivery of oxygen (OX) to the patient; c) performs alarm processing (TA) and storage (ST) of patient parameters. The particularity of the device lies in the development of the concept of recognition of motor activities, which will be classified and used for an instantaneous adjustment of the flow of oxygen depending on the type of activity. This regulation will also take into account the "inspiration-expiration" cycle. The number of necessary sensors will be minimized and their positioning will be defined to make the device the least restrictive possible for the patient.

The movement sensors may be placed, in a non-limiting manner, at the level of the trunk, the chest, the lap belt and the foot (for example in the sole of a shoe). The electronic control and regulation system will be of the outpatient type, of the appropriate size to be easily transportable.

The device will ensure the delivery of optimal oxygen flow to the patient. For this two situations will be defined. For all activities, especially those in steady state, the oxygen flow rate will be slaved to ensure the oxygen saturation rate pre-established by the practitioner (for example 92%), the central unit will adapt in real time the flow rate instantaneous oxygen to allow for a SaO2 that will tend towards the value pre-established by the doctor. For transient activities, the motor activity through the motion detection, will be taken into account to allow this instruction to be respected (oscillation of the SaO2 around the pre-established value).

Taking into account the "inhalation-expiration" cycle improves physiological conditions, relieves mucous membranes and, of course, reduces oxygen consumption. It should also mention the economic gain related to the device for patients and public services because the average expenditure of an oxygen-dependent for its oxygen consumption is of the order of 300 € per month. Taking into account 150,000 patients, the total annual expenditure amounts to € 540 million. If the objective of the project is achieved, namely an oxygen saving of more than 50%, the economy at the national level can be greater than 270 M €.

Currently marketed respiratory support systems do not include control of the flow of oxygen required by the patient.

The flow of oxygen must therefore be adjusted according to two essential data:

the oxygen level in the blood which gives important information on the efficiency of the oxygenation but whose rate of change is too slow to allow a rapid rate adjustment;

- motor activities that are immediately available to instantly adjust the flow of oxygen.

These two data have been associated with two regulatory loops: - the first, which has a relatively long reaction time of several seconds, takes into account the oxygen level measured in the blood and its role is multiple: .. check the good operation of the whole by a measurement of the real oxygenation; .. correct changes during the day of the patient's medical condition; .. gradually decrease the flow of oxygen when all activity has stopped (this important aspect not only saves oxygen but especially to limit the risk of burns of the mucous membranes by oxygen); - the second, which is based on the recognition of motor activities, has a short reaction time of a few thousandths of a second to anticipate oxygen requirements: depending on the activity, the oxygen flow is immediately modified for the purpose to avoid a sudden under oxygenation that can lead to loss of consciousness. The system can be connected to a PC via a serial, USB or wireless link, so the microcontroller board can communicate with different "Windows" interfaces. These interfaces will allow the physician to set the portable unit (target saturation threshold, minimum and maximum oxygen flow rate, etc.) according to the patient's degree of illness, so this medical device is personalized for each patient. With such a device, the patient is autonomous to do the test of 6 minutes. The health professional is close to his computer to intervene in the event of an alarm (for example: oxygen level too low); however, he may do something else or prepare and turn on the 6-minute test for the next patient. This test involves walking the patient for six minutes by observing his heart rate, blood oxygen level and distance traveled. This test must be performed twice at least 15 minutes apart. Currently, a health professional is continuously monitoring the oxygen level of the patient performing the 6-minute test to prevent any risk of syncope, therefore of falling, and falls within one minute of each other, the heart rate and the rate of oxygen in the blood.

The 6-minute test performed with the portable unit according to the invention allows the physician to observe and analyze the evolution of the physiological parameters of the patient continuously during the test period. During this test, said unit communicates with the doctor's computer via a wireless link, it sends the tracking information to the computer packet every 20s for example. On the other hand, the sending of an alarm is immediate and a priority. The information recorded during the test is stored in the memory of the portable unit and in the doctor's computer. They will be removed from the unit after validation by the doctor. During the test, if the oxygen level is too low, a visual and audible alarm is triggered on the device to allow the patient to go into the safety position and on the doctor's computer to allow a quick and immediate intervention . The device has other functions: a) If the oxygen level in the patient's blood or pulse is too low, the device can trigger an external alarm, that is, an alarm issued to a doctor by phone or over the Internet.

This function is: - performed by pairing the device with a mobile phone when the patient is out of their home: if the patient is uncomfortable, an alarm is sent via the phone and the Internet, the terminal has the possibility to be equipped with

GPS for precise location of the patient;

- Or by coupling the device with the wired telephone network when the patient is at home. b) The patient will be able to transmit the information recorded during the day on a database accessible to the doctor by the network RTC or Internet, so the doctor will be able to follow the evolution of the state of health of his patients at a distance and respect easily its obligation of observance of this pathology. c) The patient can also connect his device to the doctor's direct data manager during his control visits and observance is carried out at this time, he can also communicate via the Internet directly on the computer of his doctor or the doctor refers to the hospital that follows it. The benefits of this device are numerous and will improve the quality of life of patients.

The expected gains in oxygen reduction are of the order of 50 to 80%, which will make it possible to use smaller oxygen cylinders, therefore less heavy for the same autonomy, or to double the patient's autonomy with the same bottle.

Claims

A system for controlling and regulating the oxygen flow rate according to the physiological needs of the patient, consisting of an autonomous unit (UP) carried by the patient and remote means able to communicate with said portable unit which comprises: a) a standard medical oxygen cylinder (1) equipped with a pressure reducer; b) an oxygen distribution unit (UD) provided with a regulating solenoid valve (2) ensuring the regulated supply of oxygen in at least one nostril of the patient via a dispensing tube (3) ; c) at least one motion sensor module (4), of the accelerometer type, defining the physical activity of the patient; d) an oximetry unit (5), associated with an infrared type sensor placed on a finger or the lobe of an ear of the patient, measuring the oxygen level in the blood and the heart rate; e) a sensor (6) detecting the inspiration and expiration phases so as to allow the passage of oxygen through the control solenoid valve only during said inspiration phase; f) a central unit with:

an interface (8) for communication with a local or remote computer (9);

- a screen (10) displaying the operating parameters of the system and data relating to the patient; characterized in that each motion sensor module (4), which is of the tri-axis accelerometer type, placed on the trunk of the patient, comprises a pretreatment card (4A) defining several levels of activities pre-established by the practitioner and each corresponding to a very specific need for oxygen and a transmission / reception module (4B) transmitting to the microcontroller (7) the motor activities detected by the motion sensors (4) so as to intervene, immediately and in advance, on the oxygen requirements of the patient by acting on the oxygen flow rate of the regulating valve (2), the proportional type, after a time of the order of a few thousandths of a second; and in that the oximetry unit (5), which is associated with an infrared type sensor placed on a finger or the lobe of an ear of the patient, measures the oxygen level in the blood and the frequency which are transmitted to the microcontroller (7) so as to intervene, on a delayed basis, on the oxygen flow rates of the regulation valve (2), of the proportional type, associated with the classified activity levels in order to regulate the saturation in oxygen as close as possible to the control threshold preset preset by the practitioner, after a time of the order of a few seconds, these new values being assigned to the main control means.

2- System, according to claim 1, characterized in that the central unit (UC) comprises means for: a) recording, for several tens of days, information relating to:

- to the patient such as the accumulated use time of the system, the oxygen consumed, the actual physical activity, the heart rate, the oxygen level in the blood, the warnings due to a bad breathing, the variation of the flow rate oxygen based on the actual activity level of the patient to meet patrician prescriptions, alarms and device control parameters;

- the system, such as the level of the battery, the level of oxygen remaining in the bottle, the disconnection of one of the sensors; b) viewing said information on the screen (10); c) sending said information to the practitioner's computer (14).

3- System, according to claim 1, characterized in that the central unit (UC) comprises means for sending the data relating to the patient and the system to a database belonging to a remote surveillance network at home of the patient and consultable by the practitioner. 4. System according to claim 1, characterized in that the central unit

(UC) includes means for continuously performing the 6 minute test by providing the practitioner, at close range, the curves of the respiratory cycle, the heart rate, the oxygen level in the blood and all the patient's clinical data such as walking speed, distance traveled and distance of one step.

5. System according to claim 1, characterized in that it comprises several portable units (UP) for controlling and regulating the oxygen flow rate connected to at least one intermediate concentrator (Cl), local or remote, continuously managing patient data and alarms, itself linked to a central concentrator (CC), local or remote, also continuously managing patient data and alarms as well as all intermediate hubs so as to switch from one intermediate hub to another depending on its availability.

6. System according to claim 1, characterized in that the distribution unit (UD) comprises, in addition to the control solenoid valve (2), a bypass solenoid valve (11) associated with a bypass circuit (12). , allowing the direct passage of the flow of oxygen, either by manual action of the patient, or by action programmed by the central unit.

7- System according to claim 1, characterized in that the central unit (UC) comprises GPS location means.

8- System according to claim 1, characterized in that the central unit (UC) comprises buttons (13) able to actuate the display on the screen (10) of the level of a battery (14), the level of oxygen remaining in the bottle, the patient's heart rate, the oxygen level in the patient's blood, the flow rate of oxygen supplied to the patient, the mode of the solenoid valve (automatic or manual), the type of bottle in use.