EP1979227B1 - Device for self-monitoring and diagnosis when diving without an aqualung - Google Patents

Description

FIELD OF THE INVENTION

The present invention relates to a method and device, generally attached to the wrist, for freediving underwater diver for measuring and analyzing personal physical and environmental physiological data so as to inform him about the risks of syncope at a given moment and to bring it to the surface if necessary.

BACKGROUND TECHNOLOGY

• des moyens, du type capteurs, de saisie et de mesure de données physiques ambiantes et physiologiques du plongeur (telles que la profondeur, le temps, le taux de saturation de l'hémoglobine en oxygène (Sp02) et la fréquence cardiaque ;
• une horloge permettant la saisie desdites données à intervalles de temps réguliers ;
• des moyens, de types visuels et/ou sonores, d'indication desdites données ;
• des moyens, du type microprocesseurs, d'analyse des données saisies par rapport à un modèle préenregistré et de commande d'un dispositif signalant au plongeur un risque d'incident de plongée et déclenchant si besoin est un élément de sauvetage ;
• des moyens, du type mémoires, d'enregistrement des données saisies, des résultats de l'analyse et des données relatives au modèle préenregistré.

The methods and devices known in the field of diving generally implement a device, of the diving computer type, which generally comprises:

• sensor-type means for capturing and measuring ambient and physiological physical data of the plunger (such as the depth, the time, the saturation rate of hemoglobin in oxygen (Sp02) and the heart rate;
• a clock for inputting said data at regular time intervals;
• means, visual and / or audio types, for indicating said data;
• means, of the microprocessor type, for analyzing the data entered with respect to a pre-recorded model and for controlling a device that signals the diver a risk of a diving incident and, if necessary, triggers a rescue element;
• means, of the memory type, of the recording of the data entered, the results of the analysis and the data relating to the prerecorded model.

The closest patent is described in the document GB2390903 which deals with a device and method for the safety of an apnea diver.

The existing methods do not make it possible to determine the syncopal state of the diver in order to prevent it and to intervene. They only suspect a syncopal state if the subject is not reassembled in time.

Unfortunately, most syncope is on the surface and these processes do not detect them: the diver will drown on the surface and the computer will interpret this situation as a new apnea.

SUMMARY OF THE INVENTION

The diving device according to the invention applies to the apnea diver in static (single apnea) or dynamic (underwater hunting) situations.

He is new and original in that he is the first to detect syncope by taking into account a physiological parameter.

It is designed to be immersed in saline water or not.

• la durée totale de l'apnée et durée des apnées cumulées exprimée en secondes,
• la période de récupération exprimée en secondes,
• le taux de saturation de l'hémoglobine en oxygène (Sp02) exprimé en pourcentage,
• la fréquence cardiaque exprimée en pulsations par minutes,

ainsi que des renseignements inhérents au milieu aquatique comme la profondeur de la plongée exprimée en mètres et comporter une mémoire capable d'enregistrer au moins cinq heures (une mesure par seconde).It is multifunctional to give information related to one or more apnea in real time such as:

• the total duration of apnea and duration of accumulated apnea expressed in seconds,
• the recovery period expressed in seconds,
• the saturation rate of hemoglobin in oxygen (Sp02) expressed as a percentage,
• the heart rate expressed in pulses per minute,

as well as information related to the aquatic environment such as the depth of the dive in meters and a memory capable of recording at least five hours (one measurement per second).

It is associated with a powerful lifejacket to keep the head out of the water in a conscious or unconscious subject.

It is equipped with a syncopal accident detection system to trigger the inflation of the lifejacket if necessary.

• une prévention primaire par autocontrôle du plongeur par l'analyse des renseignements en temps réel ou à posteriori par relecture des données sur ordinateur : par exemple des apnées un peu trop poussées lui indiqueront une désaturation trop profonde et lui feront réaliser qu'il faut pousser un peu moins celles-ci ;.
• une prévention secondaire par le dépistage des accidents syncopaux par l'ordinateur au moyen d'une analyse du taux de saturation Sp02 en fonction de la vitesse de désaturation : en cas de détection d'un signal faisant suspecter un état syncopal, un test clinique de vitalité est proposé au plongeur (appui sur un bouton de la montre) : soit le plongeur est conscient et la pression du bouton annule le gonflage du gilet de sauvetage, soit le plongeur est inconscient et l'absence de pression du bouton au bout d'un temps prédéterminé entraîne alors le gonflage du gilet.

Among the causes of mortality at sea, apnea accidents (underwater fishing or pure apnea) are the most frequent. Recent technological developments in the field of scuba diving and the corresponding regulations have considerably reduced accidents in this area. On the other hand, the mortality of accidents related to underwater hunting are still as frequent and fatal. It is in this context that this device takes all its interest. It may allow primary and secondary prevention of underwater hunting accidents:

• a primary prevention by self-monitoring of the diver by the analysis of the information in real time or a posteriori by rereading of the data on computer: for example apneas a little too pushed will indicate to him a too deep desaturation and make him realize that it is necessary to push a little less than these;
• secondary prevention by detection of syncopal accidents by the computer by means of an analysis of the saturation rate Sp02 as a function of the rate of desaturation: in the event of detection of a signal making suspect a syncopal state, a clinical test of vitality is proposed to the diver (pressing on a button of the watch): either the diver is conscious and the pressure of the button cancels the inflation of the lifejacket, either the diver is unconscious and the absence of pressure of the button at the end of a predetermined time then causes the inflation of the vest.

It does not apply to the practice of scuba diving in its use of syncopal detection and the rescue process. It can only be used for indicative heart rate in said diver.

The device according to the invention is defined by claim 1.

The values of the saturation rate and the slope of its variation, measured on an apnea diver, are compared, at each moment, with the model, pre-recorded, which is represented by the curve "saturation rate according to the slope of its variation which delimits the non-syncopal and syncopal state areas and which has been established experimentally from a well-defined number of subjects for which the rate and slope of each of them have been measured. its variation in syncopal state limit.

The device for its implementation is generally attached to the wrist, and essentially comprises means for capturing and measuring ambient physical and physiological data of the plunger (such as depth, time, hemoglobin saturation rate sensors). oxygen (Sp02) and heart rate).

This device is advantageously contained in an envelope which holds it against the part of the body concerned at a temperature sufficient to record a reliable pulsatility of the signal.

Said envelope is advantageously an improved diving glove which also incorporates the wire connection which connects the digital sensor to the dive device via a sealed interface.

PRESENTATION OF FIGURES

• la figure 1 représente la courbe « taux de saturation en fonction du temps pour un plongeur donné ;
• la figure 2 représente la courbe « taux de saturation en fonction de la pente de sa variation » qui a été établie à partir d'une pluralité de plongeurs pour lesquels on a mesuré, pour chacun d'eux, le taux de saturation SpO₂ et la pente de sa variation en limite d'état syncopal et qui délimite la zone de passage d'un état non syncopal ou très probablement non syncopal à un état syncopal ou très probablement syncopal.

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 appended figures in which: :

• the figure 1 represents the curve "saturation rate as a function of time for a given diver;
• the figure 2 represents the curve "saturation rate as a function of the slope of its variation" which has been established from a plurality of divers for which the saturation rate SpO ₂ and the slope of each of them have been measured. its variation in syncopal state limit and which delimits the zone of passage from a non-syncopal or very probably non-syncopal state to a syncopal or very probably syncopal state.

DETAILED DESCRIPTION OF THE INVENTION

• des moyens de saisie et de mesure de données physiques ambiantes et physiologiques du plongeur (tels que capteurs de profondeur, de temps, de taux de saturation de l'hémoglobine en oxygène (Sp02) et de la fréquence cardiaque).
• une horloge permettant la saisie desdites données à intervalles de temps réguliers ;
• des moyens, des types visuels et/ou sonores, d'indication desdites données ;
• des moyens, du type microprocesseurs, d'analyse des données saisies par rapport à un modèle préenregistré et de commande d'un dispositif signalant au plongeur un risque d'incident de plongée et déclenchant si besoin est un élément de sauvetage ;
• des moyens, du type mémoires, d'enregistrement des données saisies, des résultats de l'analyse et des données relatives au modèle (M) préenregistré.

The self-diagnosis and rescue device for snorkel diving diver is implemented by means of a diving device comprising essentially:

• means for capturing and measuring the ambient and physiological physical data of the plunger (such as depth, time, saturation oxygen hemoglobin (Sp02) and heart rate sensors).
• a clock for inputting said data at regular time intervals;
• means, visual and / or audio types for indicating said data;
• means, of the microprocessor type, for analyzing the data entered with respect to a pre-recorded model and for controlling a device that signals the diver a risk of a diving incident and, if necessary, triggers a rescue element;
• means, of the memory type, of the recording of the data entered, the results of the analysis and the data relating to the pre-recorded model (M).

Said device consists, for automatically detecting a risk of syncope during dive, to analyze the rate of saturation desaturation (Sp02) which is established according to the slope (P) of said variation in the vicinity of said rate at a given instant given.

The values of the saturation rate Sp02 and of the slope (P) of its variation, measured on an apnea diver, are compared, at each instant, with the model (M), prerecorded, which is represented by the curve "saturation rate according to the slope of its variation "which delimits the zones of non-syncopal (ZNS) and syncopal state (ZS) and which has been established experimentally from a well-defined number of subjects for which it has been measured for each of them, the Sp02 rate and the slope (P) of its syncopal state limit variation.

In case of detection of a risk of syncope, there is emission of a signal, perceptible by the diver, which must be interrupted by the latter in a definite time, otherwise the rescue element will be activated by the autonomous control means.

According to an alternative embodiment of said device, the diving depth can also be taken into account, to determine the risk of syncope.

The device also consists in displaying, in real time, on the diving device, the diving depth, the heart rate, the saturation rate, the apnea time and the recovery time.

The device, which is generally attached to the wrist, essentially comprises means, of the sensor type, of capturing and measuring the physical and ambient physiological data of the plunger such as the diving depth, the apnea time and the recovery time, the saturation rate of oxygen hemoglobin (Sp02) and heart rate.

These capture and measurement means are advantageously contained in an envelope which holds them against the part of the body concerned at a temperature sufficient to record a reliable pulsatility of the signal.

Said envelope is advantageously a suitable dive glove which also incorporates the wire connection which connects the digital sensor to the dive device via a sealed interface.

The rescue element is advantageously a vest provided with a CO2 capsule triggered by the clock when a syncope risk signal is issued and the diver has not invalidated said signal.

• un boîtier étanche à 10 atmosphères et un capteur de taux de saturation (Sp02) intégré dans un gant en néoprène : le gant et le capteur seront consommables, mais réutilisables en l'absence de détérioration ;
• un gilet de sauvetage avec capsule de CO2 reliés à la montre par interface électronique : ladite capsule sera également consommable et le gilet et la montre seront réutilisables.

Said diving device more particularly comprises:

• a waterproof case with 10 atmospheres and a saturation rate sensor (Sp02) integrated in a neoprene glove: the glove and the sensor will be consumable, but reusable in the absence of deterioration;
• a lifejacket with CO2 capsule connected to the watch by electronic interface: said capsule will also be consumable and the vest and the watch will be reusable.

It is equipped with a waterproof connection able to adapt to both the Sp02 sensor and to a computer via a PC interface.

All functions are enabled when connecting the Sp02 sensor.

Software allows you to output all data on the computer and provide a graph expressing the heart rate, the Sp02 rate and the depth as a function of time.

The Sp02 sensor is integrated into a neoprene glove connected to the watch via a cable that can be molded into the glove.

The glove is at the same time a little loose at the level of the fingers carrying one or two sensors to avoid any compression and insulating enough of the cold to mitigate a possible risk of peripheral vasoconstriction due to cold, compression and cold being all two of the factors altering the quality of the signal.

The device is supposed to give a value of Sp02 only if the pulsatility of the signal is reliable.

On the other hand, the glove also makes it possible to limit the artefacts of movements.

The lifejacket is designed to lift the diver to the surface and keep his head out of the water.

A prospective study was carried out on 50 divers corresponding to 300 apneas of which 200 in static and 100 in dynamics. During this study, the following data was identified through the use of a prototype.

Of the total data, 23 syncopal or presyncopal accidents were recorded.

• de proposer un dispositif permettant de détecter dans les 30 secondes les risques d'accidents syncopaux ;
• d'extraire des caractéristiques graphiques obtenues, les moyens de prédire le déclenchement des syncopes et par conséquent de proposer des algorithmes de détection ;
• de concevoir un dispositif industrialisable répondant au problème posé.

The objectives of this study were:

• to propose a device making it possible to detect within 30 seconds the risks of syncopal accidents;
• extracting graphical characteristics obtained, the means of predicting the onset of syncope and consequently of proposing detection algorithms;
• to design an industrializable device answering the problem posed.

The diving device records, every second, raw data such as: the depth and total time of the apnea, the rate of Sp02 and the heart rate. It calculates from these data the desaturation slope which is defined as the rate of desaturation in percentage per second.

The case study showed that the desaturation slope associated with the saturation rate is the determining factor for the detection of syncope.

Indeed, at a given time and for a low Sp02 rate, the value of the slope will have an influence on the risk of syncope.

In order to detect a syncope as a function of the Sp02 rate, the computer calculates the desaturation slope, according to a mathematical model, according to the last Sp02 measurements. The desaturation slope corresponds approximately to the rate of desaturation (slope of the tangent to the Sp02 curve at time t, expressed in% / second).

Each second, it analyzes a rate of Sp02 associated with a slope.

At each rate of Sp02 corresponds a limit slope, determined by the clinical study carried out beforehand, above which a syncopal accident is highly suspect. This data will be saved in the computer database.

Each second, the rate of Sp02 and its corresponding slope are analyzed: if the slope is greater than or equal to that prerecorded in the database for the same rate of Sp02, the computer will then detect a syncopal signal; otherwise he will not detect it.

To detect a syncope based on the Sp02 rate and depth, the computer analyzes, at each second, the rate of Sp02 as a function of depth. It has also been predetermined, in the computer database, for each depth, a Sp02 threshold below which a syncopal accident is highly suspect.

If at a given time, the diver being at a given depth, the measured Sp02 rate is lower than that recorded in the database and corresponding to the same depth, the computer will detect a syncopal signal; otherwise he will not detect anything.

To also involve the duration of the apnea, each diver will have to program his modifiable apnea limit time according to its shape and the depth at which it dives.

The computer detects the beginning of the apnea when the depth is greater than a determined value and the end of the apnea when it becomes lower than said value in order to operate the stopwatch within said limits and to return it to zero at the end of apnea.

If the apnea time is greater than the programmed time, the computer will detect a syncopal signal; otherwise he will not detect it.

• émission d'un premier signal sonore et/ou lumineux pendant 10 secondes que le plongeur doit arrêter en pressant n'importe quel bouton de la montre ;
• si le plongeur n'intervient pas dans les dix secondes attribuées, le dispositif déclenche alors le gonflage du gilet de sauvetage ;
• si le plongeur intervient dans les 10 secondes attribuées, un deuxième signal sonore est émis au bout de dix secondes, puis un troisième dans les mêmes conditions, soit donc au total 30 secondes de contrôle clinique de la vitalité du plongeur.

If a syncopal risk is detected, the vitality test procedure may be as follows:

• emitting a first sound and / or light signal for 10 seconds that the diver must stop by pressing any button on the watch;
• if the diver does not intervene within the ten seconds allotted, the device then triggers the inflation of the lifejacket;
• if the diver intervenes within the 10 seconds allocated, a second sound signal is emitted after ten seconds, then a third under the same conditions, ie a total of 30 seconds of clinical control of the vitality of the diver.

The detection of an alarm threshold a posteriori to control the apnea to come can be established for example in case of desaturation below a predetermined threshold by the diver (for example 85): a non-audible alarm may signal to the diver that his apneas are a little too much pushed.

Several recordings at sea were made with or without glove in cold water or not, with analysis of the quality of the signal (pulsatility of the signal), and artifacts: total absence of recorded value or values not corresponding to the diver's clinical condition such as aberrant heart rate or sudden desaturation while the diver is on the surface.

In hot water the use of the glove gives a good signal amplitude and the almost total absence of artifacts. The interpretation of the curves is possible and interesting for the diver and for the detection of a syncope by a possible computer.

In hot water the absence of use of the glove quickly gives a low signal amplitude and a number of artifacts making it impossible to interpret the recorded Sp02 curves. The diver can still get a real-time idea of his heart rate, the rate of Sp02 is very unreliable. The screening according to the rate of Sp02 of a possible syncope would then be random.

In cold water (up to 8 degrees) the use of the glove gives a satisfactory amplitude of signal but a little less good than in hot water. There are only few artifacts and the interpretation of the curves remains possible and interesting for the diver and for the detection of a syncope by a possible computer.

In cold water without using the glove the signal is very quickly almost completely artefacted.

As a result, the use of a glove is essential for reliable recording for the diver or for possible detection of syncope.

This is explained by at least two known physiological phenomena: movement artefacts and peripheral vasoconstriction artifacts due to cold.

Movement artifacts are secondary to movement of the plunger and sensor relative to the plunger. Most new pulse oximeters help to eliminate the patient's movement artifacts. However during movement in the water the sensor will also move relative to the diver if it is not fixed correctly. This is the first role of the glove.

When the body is exposed to cold the body redistributes blood to the noble organs and reduces the vascularization of others: there is a peripheral vasoconstriction and capillary blood flow in the fingers is decreased; the pulsatility is reduced accordingly resulting in a disturbed signal.

The only exposure to cold fingers causes the same reaction in the fingers without even the diver is hypothermia. The only solution is to place your finger in a warm place. This is also what a neoprene glove does.

Most neoprene gloves exert significant pressure on the fingers and also cause mechanical peripheral vasoconstriction.

It is therefore necessary that the finger or fingers on which the sensors are positioned are not too tight. In our experience the simple fact of dilating the finger of the glove or is positioned the sensor allowed to cancel the loss of signal amplitude.

The analysis of syncope and non-syncope curves showed that in all cases above a certain threshold of Sp02 (80 for example), syncope never occurred and that below a certain threshold (30) The subjects were almost always in syncope.

Of course, the invention is not limited to the embodiments described and shown for which other variants may be provided without departing from the scope of the invention (determined by the content of the claims).

In particular, we can provide a version without the survival device ie a version comprising a dive computer provided with a pulse oximeter suitable for underwater use whose sensor is integrated in a glove.

Claims (9)

1. Device for self-monitoring and diagnosis when diving underwater comprising primarily:

   - means for recording and measuring physiological and ambient physical data of the diver (such as depth, time, oxygen haemoglobin saturation rate (Sp02) and heart rate sensors);

   - a clock making it possible to record said data at regular intervals of time;

   - means, of the visual and/or auditory type, for indicating said data;

   - means, of the microprocessor type, for analysing the recorded data in relation to a pre-recorded model for controlling a device informing the diver of a risk of a diving incident and triggering if needed a rescue element (of the inflatable jacket type);

   - means, of the memory type, for saving the recorded data, results of the analysis and the data relating to the pre-recorded model (M);

   characterised in that it consists, in order to automatically detect a risk of syncope during a dive, in analysing the speed of desaturation of the oxygen haemoglobin saturation rate (Sp02) which is established as a function of the slope (S) of the variation of the saturation rate (Sp02) at a given time.
2. Method, according to claim 1, characterised in that the values of the saturation rate (Sp02) and of the slope (S) of its variation, measured on a diver without an aqualung, are compared, at each instant, to the pre-recorded model (M), which is represented by the "saturation rate as a function of the slope of its variation" curve which delimits areas of a non-syncopal state (NSA) and of a syncopal state (SA) and which was established experimentally using a well-determined number of subjects for whom was measured, for each one of them, the saturation rate (Sp02) and the slope (S) of its variation at the limit of syncopal state.
3. Method, according to claim 2, characterised in that it consists, in the event a risk of syncope is detected, in emitting a signal, that can be perceived by the diver, which must be interrupted by the latter within a well-determined timeframe, otherwise the rescue element will be actuated by the means of control.
4. Method, according to any of claims 1 to 3, characterised in that it consists in further taking into account, in order to determine the risk of syncope, the diving depth.
5. Method, according to any of claims 1 to 4, characterised in that it consists in displaying, in real time, on the diving device, the diving depth, the heart rate, the saturation rate (Sp02), the free dive time and the recovery time.
6. Method, according to any of claims 1 to 5, characterised in that it is fastened to the wrist.
7. Method, according to any of claims 1 to 5, characterised in that it is contained in an adapted diver's glove which maintains it against the relevant part of the body at a temperature making it possible to record a reliable signal.
8. Method, according to claim 7, characterised in that the diver's glove further incorporates the wired link that connects the digital sensor to the diving device by the intermediary of a sealed interface.
9. Method, according to claim 1, characterised in that the rescue element, of the jacket type, is provided with a capsule of CO2 triggered by the clock when a risk of syncope signal is emitted and the diver has not invalidated said signal.

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