Method for treating episodes of apnoea and/or hypopnea and system for detecting said episodes

Abstract

A method for treating episodes of apnoea and/or hypopnea is provided. The method has the steps of: a) detecting or predicting an episode of apnoea and/or hypopnea by means of at least one sensor selected from a respiratory pressure sensor, a pulse oximeter, an acoustic sensor and/or a respiratory temperature sensor; and b) emitting an electrical signal by means of an electrical actuator connected to at least one submental nerve and/or muscle, the electrical signal having a bipolar waveform and a frequency between 5 and 100 Hz.

Claims

1. A method for treating episodes of apnoea and/or hypopnea of a user, which comprises the steps of: a. predicting an episode of apnoea and/or hypopnea of the user comprising: quantifying a current respiratory signal comprising: measuring a current respiratory pressure value by a respiratory pressure sensor, and measuring a current respiratory temperature value by a respiratory temperature sensor; comparing, by a processor, the measured current respiratory pressure value and measured current respiratory temperature value with corresponding thresholds, wherein each threshold is dynamic and is automatically modified based on historical measured values of the user, wherein the historical measured values are stored in a memory; and b. generating a stimulus comprising: emitting an electrical signal by an electrical actuator non-invasively connected to at least one submental nerve and/or muscle of the user, wherein the electrical signal has a bipolar waveform and a frequency between 5 Hz and 100 Hz; wherein the bipolar waveform comprises a positive cycle and a negative cycle, and wherein one of the positive and negative cycles has a maximum value which is 40% greater than the maximum value of the other positive and negative cycle.

2. The method according to claim 1, wherein the bipolar waveform comprises a delay between the positive cycle and the negative cycle of between 0 and 10 ms.

3. The method according to claim 1, wherein the electrical signal as a peak-to-peak intensity is between 1 and 20 mA.

4. The method according to claim 1, wherein the historical values of the respiratory signal comprise a statistical value of the latest measurements.

5. The method according to claim 1, wherein the step of quantifying the current respiratory signal further comprises measuring a heart rate and a blood oxygen saturation by a pulse oximeter.

6. The method according to claim 1, wherein quantifying the current respiratory signal further comprises measuring a respiratory sound by an acoustic sensor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The attached figures show an embodiment of the system according to the present invention in an illustrative and non-limiting manner, in which:

(2) FIG. 1 shows an embodiment of a system for detecting and treating apnoea and/or hypopnea according to the present invention.

(3) FIG. 2 shows a modular schematic view of an example of a system according to the present invention.

(4) FIG. 3 shows an example of a standard pulse of a treatment signal according to the present invention.

(5) FIG. 4 shows an example of a treatment signal comprising a standard pulse train.

(6) FIG. 5 shows another example of a treatment signal comprising a standard pulse train with variable intensity.

DETAILED DESCRIPTION OF AN EMBODIMENT

(7) FIG. 1 shows a preferred embodiment of a system according to the present invention, wherein the system has a sensing module (1) comprising at least one sensor of the respiratory signal of the user in which said sensor is, for example, a pressure sensor measuring the amplitude of the respiratory signal. Furthermore, said sensor is disposed, for example, by means of a cannula, in the nasal cavity of the user, and furthermore there is a sensing module placed on the arm or chest of the patient (3), or anywhere else.

(8) The pressure sensor measures the respiratory signal of the user (3) by the highly sensitive detection of pressure variations. Disruptions from the environment are thereby prevented, and higher reliability of the detection of the respiratory signal is achieved. Examples of said respiratory signal sensors can be based on pressure, temperature and/or flow sensors. In any case, the objective is to determine the characteristics of the breathing of the user.

(9) Moreover, the system has an actuator (2) with means for being attached to the user (3). In the example of FIG. 1, the actuator (2) has side pieces (21) for being arranged around the ears of the user (3). The actuator further comprises electrodes (22) for acting non-invasively on at least one muscle and/or a nerve of the morphology connected to the airway of the user, for example, a submental muscle connected to the airways.

(10) Additionally, the system has a processor with the capacity to communicate with the sensing module (1) and the actuator (3), which will be explained in further detail in reference FIG. 2.

(11) FIG. 2 shows a schematic view in which there is provided a processor incorporating a memory and data processing means. The sensing module (1) is provided as input to said processor and a signal is provided as output to the actuator (2) for the processing of the signals, to a display module (8) or to a memory (9) where data relating to the emitted output signals can be stored. The means for the communication of the processor with the actuator are preferably cables, and the means for the communication with the sensing module are preferably cables, although completely wireless and partially wired and/or wireless configurations are also contemplated in the present invention.

(12) In terms of the sensing module (1), it may comprise additional sensors which allow improving an eventual prediction/detection of an episode of apnoea and/or hypopnea. Namely, it is contemplated that the following additional sensors can be provided: Temperature sensor: Allows measuring airflow temperature variations, which data can be used complementarily or alternatively to the respiratory signal data. This variable provides additional information in order to use it if required in recording variables of patients in some circumstances. A body temperature sensor would measure the body temperature of the patient should one be arranged. Pulse oximeter sensor: Allows measuring the heart rate and blood oxygen saturation. This measurement improves the diagnostic parameters so as to improve, along with other variables, the detection of episodes of apnoea and/or hypopnea in some cases. This measurement is usually performed non-invasively by means of optical sensors. Electromyography sensor: Allows measuring muscle tone in the region of the neck relating to the muscles connected to the airway. It is useful for monitoring the state of the airways of the patient for self-adaptation of the stimulation signals to the characteristics and situation of the patient, mainly in the therapeutic training mode. Position and motion sensor: Allows determining the position and motion of a patient, for example by means of a three-dimensional inertial sensor by means of an IMU (Inertial Measurement Unit) or by means of an accelerometer, and provides additional data for establishing the processing of the information for diagnosis, taking into account the mobility and position of the patient at the time of detecting the episode and throughout his or her entire sleep cycle. Acoustic sensor: Allows improving the detection of snoring and respiratory sounds and provides additional data about apnoea and/or hypopnea. It can be used in certain circumstances to relate it to other variables.

(13) Subsequently, the signals coming from the sensors to be used are sent to the processor and, namely, to an event detection module (4), in which said module analyses the current signals with respect to earlier signals stored in a memory.

(14) Namely, the event detection module is provided with a memory in which the signals coming from the sensing module (1) are stored together with data related to the moment when the measurements are taken, for example, the time or a temporal reference type. Subsequently, the module analyses the current data received directly from the sensing module (1), and by means of comparison means, compares the earlier data series with the current measurement for, subsequently, by means of determination means, calculating whether there is a reduction of the current measurement of the respiratory signals below a threshold level stored in the memory. It also has emission means for emitting a treatment signal if the reduction is below the threshold level. Said event detection module can be updated in real or quasi-real time with respect to the measurements performed in the user.

(15) If it is determined that there is a reduction below a threshold level during a given time, this means that the user will soon experience an episode of apnoea and/or hypopnea, therefore in an exemplary embodiment, the actual event is stored in an event recording module (7). Said thresholds can be predetermined thresholds or they can be defined by means of a calibration method so as to adapt them to the user, and additionally, said detection thresholds can be automatically adapted taking into account earlier measurements and can be adapted to the characteristics of the patient, for example, by means of artificial intelligence algorithms.

(16) Alternatively, the system can have an actuator (2) which exerts on the user, through non-invasive means, an action, for example, to stimulate the morphology involved in OSAHS. Accordingly, the processor can have a stimulus generation module (5), where the stimuli can be, for example, signals controlling an electric generator connected to the actuator and electrodes for stimulating the morphology involved in OSAHS. Moreover, said outputs of the stimulus generation module can also be sent to a screen (8) to be displayed in real time and/or stored in an event memory (9).

(17) Additionally, the system can have a remote transmission module (6) which allows transmitting, for example, the data stored in the event recording module (7) to a remote server such as the server of a medical service.

(18) FIG. 3 shows an exemplary embodiment of a standard pulse (20) for a treatment signal according to the present invention. Namely, the signal of FIG. 3 shows the waveform of the standard pulse (20) which contains a positive part of amplitude (Ap), a time of duration at half its amplitude (T.sub.1) and a form according to the temporal function (f.sub.1(t)); it furthermore has a negative part of amplitude (An), a time of duration at half its amplitude (T.sub.2) and a form according to the temporal function (f.sub.2(t)).

(19) Additionally, the standard pulse (20) can have a period of the standard pulse signal or time between repetitive pulses (T), a time between positive pulse and negative pulse (T.sub.3), a cycle time of the positive and negative standard pulse (T.sub.c), a pulse-free time at level zero between cycles of the standard pulse (T.sub.4), a positive pulse rise time (ts.sub.1), a positive pulse decay time (tb.sub.1), a rise time of the negative pulse (ts2) and a decay time of the negative pulse (tb2).

(20) The form of the standard pulse (20) may comprise of a positive wave section and a negative wave section with the times in zero state distributed such that it has a symmetrical effect; said configuration is particularly advantageous because, since it is sent to an electrode to act on the submental morphology, it generates significant opening of the airways, and prevents uncomfortable involuntary movement gestures of the lips and chin when the stimulation signal is received.

(21) The intensity levels and frequency of the pulses are designed to produce the desired depth effect of the wave in order to reach the suitable muscle or nerve, and efficacy of the stimulation, and minimise the side effects of temperature increase of the skin and pain and unwanted gestures and movements.

(22) FIG. 4 shows an embodiment in which the treatment signal comprises a standard pulse train (TPp) which can be, for example, a continuous train of duration (Tp), of standard pulses (Pp), of amplitude (Ap) and relaxation time of the pulse train of duration (Tr). The duration of the pulse train is TPp.

(23) In one embodiment, the treatment signal can be maintained continuous, but these interruptions of the standard pulse train could be applied, whereby providing an additional parameter for improving the efficacy of the stimulation.

(24) FIG. 5 depicts a particular embodiment of a treatment signal according to the present invention in which the form of the progressive variation in intensity of the stimulation wave (VPI) formed by standard pulse trains (TPp). The activation signal of the treatment wave (Sa) starts the stimulation process. It begins with standard pulse trains TPp with an initial amplitude (Api) which is less than the level necessary for causing the airway to open. This level can progressively increase until reaching the final amplitude of the stimulation wave (Apf). This final amplitude is determined by the resolution of the episode due to the sufficient opening of the airway occurring, which is detected by the sensors, or by reaching a safety threshold. At this time, the deactivation signal of the treatment wave (Sd) is generated, in which the initial and final amplitude thresholds are adjusted to the characteristics and state of the patient.

(25) The incremental increase in the amplitude of the treatment signal is particularly relevant in that it allows starting a treatment with a low initial amplitude (Api). Therefore, if treatment is sufficient with said low amplitude and the episode of apnoea or hypopnea is solved, it is not necessary to increase the intensity of the signal. It is thereby ensured that the treatment is performed with the least action possible on the patient and with the lowest possible energy consumption.

(26) In FIG. 5, the time of duration of each activation of the treatment wave (Tv.sub.1) is determined by the final amplitude of the stimulation wave (Apf) described in the preceding paragraph.

(27) The silence (signal-free) times of each activation of the stimulation wave (Ts.sub.2) are determined by the time lapsing between the resolution of an episode and the detection of a new episode. In another embodiment of the present invention, the action and silence times and levels are determined by a training sequence.

(28) The form of the envelopment of the progressive variation in intensity of the stimulation wave (VPI) of FIG. 5 has a temporal function Fv(t), which is usually a ramp function.

(29) A table is shown below with the different episodes that can be detected and/or treated with a device according to the present invention. The table shows the values currently accepted by the medical community. Although the detection parameters are susceptible to changes, said changes in detection parameters can likewise be modified in a device according to the present invention in order to accommodate said changes in criterion.

(30) TABLE-US-00001 Obstructive Absence or reduction >90% of the respiratory signal apnoea (thermistors, nasal cannula or pneumotachograph) of >10 seconds in duration in the presence of respiratory effort detected by the respiratory pressure sensors. Central apnoea Absence or reduction >90% of the respiratory signal of >10 seconds in duration in the absence of respiratory effort. Mixed apnoea A respiratory event which usually begins with a central component and ends in an obstructive component. Hypopnea.sup.a Discernible reduction (>30% and <90%) of the amplitude of the respiratory signal of >10 seconds in duration. Respiratory Period >10 seconds of progressive increase in respiratory effort-related effort. It can also be detected by short flow limitation- micro-arousals flattening periods of the respiratory signal. (RERM)

(31) Each of the treatment parameters must be calibrated with respect to the patient and calibration is performed by configuring the parameters such that they cause the least possible discomfort for the patient and open the airways.

(32) In tests performed on actual subjects, this perception or discomfort is virtually nil, achieving a very significant opening of the airway. Accordingly, this achieves a benefit for the patient as it causes virtually nil discomfort.