HK40051997A - Vibroacoustic device and method for treating restrictive pulmonary diseases and improving drainage function of lungs - Google Patents

Description

The present invention relates to a therapeutic system for the treatment of restrictive pulmonary diseases (such as Acute Lung Injury and Acute Respiratory Distress Syndrome), using vibroacoustic effects which are applied to a patient's chest.

BACKGROUND

Patients with obstructive pulmonary diseases such as cystic fibrosis, bronchiectasis, bronchial asthma and Chronic Obstructive Pulmonary Disease ("COPD") often find it difficult to breathe and experience shortness of breath. This can be attributed to the poor drainage function of the patients' bronchi. Likewise, patients with restrictive pulmonary diseases for instance post-operative patients and especially those on mechanical ventilation also suffer from impaired breathing due to reduced and/or absent cough reflex.

For over a century, postural drainage and percussion have been widely used as a form of chest physiotherapy to improve bronchial drainage and sputum evacuation. However, such manual techniques are uncomfortable, labour intensive, time-consuming and may not be suitable for patients who have undergone thoracic or cardiovascular surgery.

Various apparatus such as the "Percussionaire", "CoughAssist" pneumatic vests and vibrating systems have since been developed for the treatment of such obstructive pulmonary diseases.

US2017/157429 discloses an apparatus that includes a frequency generator to generate an electrical signal. The apparatus also includes an acoustic transducer operably coupled to the frequency generator. The acoustic transducer converts the electrical signal into a first acoustic signal. The apparatus also includes an applicator operably coupled to the acoustic transducer. The applicator includes an acoustic generator to generate a second acoustic signal based on the first acoustic signal. The applicator also includes an applicator interface configured to apply the second acoustic signal to a patient.

WO2012/210266 discloses an apparatus that includes a signal generator to generate an electrical signal. The apparatus also includes a patient interface configured to be applied to at least a portion of a chest of a patient during use. The patient interface includes an acoustic transducer operably coupled to the signal generator to convert the electrical signal into an acoustic wave. The patient interface further includes an acoustic coupler operably coupled to the acoustic transducer to transmit the acoustic wave from the acoustic transducer toward at least one portion of the chest of the patient. The acoustic wave has a frequency from about 30 Hertz to about 120 Hertz.

A pneumatic system described in US Patent No. 7,115,104 by N P Van Brunt and D J Gagne produces high frequency chest wall oscillations for the purpose of improving lung airway clearance. The system is used in combination with an inflatable vest secured to the chest of the patient. On the other hand, the system disclosed in US Patent No. US 8,443,796 by A Hughes delivers acoustic vibrations into the airways while the patient breathes through a mouthpiece. Nevertheless, the efficacy of these systems and techniques have been limited as these systems cannot be effectively used for intubated patients and those with chest-wall injuries or wounds. Further, they also require relatively long treatment duration of at least 10 to 20 minutes per session. Such long treatment sessions may cause discomfort to patients, especially those who feel fatigued and/or breathless from their subsisting lung diseases and/or ailments.

More importantly, there is also presently no therapeutic system which uses vibroacoustic influence for the treatment of restrictive pulmonary diseases such as Acute Lung Injury ("ALI") or Acute Respiratory Distress Syndrome ("ARDS"). Currently, the treatment regimen for patients with ALI and ARDS typically consists of "Lung Recruitment Manoeuvres" using a ventilator to prevent the collapse and/or deflation of the alveoli. However, this form of treatment is dangerous and cannot therefore be used for all types of patients.

This is because such Lung Recruitment Manoeuvres involve the periodic increase of Positive End Expiratory Pressure ("PEEP"), creating a high peak airway pressure, in order to spread and expand the alveoli in the lungs. The residual pressure is then used to prevent alveolar deflation and/or collapse. Due to the high levels of PEEP applied to open the alveoli, patients are inevitably exposed to the risks of damage to the lung parenchyma, development of multiple micro-atelectasis, and even potential pulmonary barotrauma (lung tissue rupture).

Therefore, an urgent need exists for a safe and effective method for treating restrictive pulmonary diseases. Further, there is also a need for an improved bronchial drainage technique which is effective while minimizing any discomfort or inconvenience caused to the patient. It is also desirable to have a comprehensive system that can be used in the treatment of both restrictive and obstructive pulmonary diseases for all types of patients, while preventing further complications at the same time.

Accordingly, the present invention seeks to obviate or mitigate all of the above limitations of the prior art by providing an efficacious solution to overcome the various shortcomings in the current treatment regimes.

SUMMARY OF THE INVENTION

According to the present invention, there is provided a system as hereinafter set forth in Claim 1 of the appended claims.

The system of the invention can be used for treatment of restrictive pulmonary diseases such as pneumonia, interstitial lung disease, ALI and ARDS, which occur when these is a built up of atelectasis in the lung tissue. The application of vibroacoustic effects on the lungs have yielded good results in the prevention of atelectasis, and enables the alveoli to be maintained in an open state without the need for aggressive Lung

Recruitment Manoeuvres. When used against the background of residual pressure (i.e. constant low positive airway pressure sufficient to maintain the alveoli in an open state), the vibrations and resonance effect promote the unfolding of the alveoli. The use of high peak airway pressure is therefore not required. This technique can be described as "Vibroresonance-Recruitment-Manoeuvre".

Further, the Vibroresonance-Recruitment-Manoeuvre can be combined with the use of artificial pulmonary ventilation or non-invasive ventilation, depending on the severity of the patient's condition. For instance, where the patient breathes through a mask against the backdrop of Constant Positive Pressure Airway Pressure ("CPAP"). In mild cases, it may be sufficient to apply the Vibroresonance-Recruitment-Manoeuvre technique to breathing exercises and/or the use of breathing simulators to maintain the alveoli in an open state and prevent alveolar deflation and/or collapse.

Another positive effect of the Vibroresonance-Recruitment-Manoeuvre technique is the increased hydrostatic fluid redistribution in patients. As a result of lying in a supine position for long periods of time, fluids gradually collect in the lower-back departments of the patients' lungs and interstitial tissue due to gravity. To improve the ventilation of the lower lung departments and redistribution of the fluids, patients often undergo kinetic therapy. From time to time, the patient is turned from one side to another, and is even made to lie face-down for long periods of time. However, this method is time-consuming and can be extremely uncomfortable for patients, especially when there is significant respiratory distress.

When used in combination with kinetic therapy, the application of vibroacoustic effects on those departments of lungs situated in a higher position enables the redistribution of fluids by gravity to be accelerated. Further, the vibroacoustic influence also promotes the opening of the atelectatic alveolus and drainage along the adducting bronchi. This further improves the drainage of fluids in the lungs and interstitial tissue within a shorter period of time.

As described above, not only does the system of the present invention increase the lung breathing volume of patients suffering from restrictive lung diseases, it also prevents hypostatic pneumonia and complications in patients with COPD due to the built up of fluids in intubated patients.

Using acoustic spectrum measurements, the resonant frequency of the lungs was observed to be between the range of 20 Hz to 300 Hz in general. As such, the wide frequency range produced by the system would allow the vibroacoustic effects to be propagated effectively to the various components of the lungs, and thereby increase the efficacy of the treatment.

To improve the bronchial drainage, vibroacoustic influence is applied to the patient's chest. The complex modulating signal generated by the system has a number of effects, including vibration, reverberation, excitation and resonance, which contributes to the release and movement of sputum. The vibrations are propagated to the lung parenchyma, causing the loosening of bronchial mucus from the bronchial walls. Under the influence of vibrations, more sections of the lung parenchyma are exposed to greater frequency fluctuations which promotes the movement of sputum from the small and medium-sized bronchi to the larger bronchi and eventually out of the lungs.

The present invention thus replaces manual chest massages via other percussion-oriented methods and/or systems, and significantly increases the effectiveness of sputum evacuation. As a result, the duration of each treatment session can be reduced to less than 5 minutes per session.

The vibroacoustic influence is synchronised with the patient's respiratory cycles for greater effectiveness, while minimizing the exposure of other damaged organs to vibratory effects. For example, the treatment can be customised for patients with cerebral edema as well, amongst others.

In one method of treatment, the patient will be maintained in a position to allow the affected areas of the lungs to be elevated while vibroacoustic effect is applied by manually placing the vibroacoustic transducer over the surface of the chest. The compression-type dynamic head of the vibroacoustic transducer is contained in a plastic housing with holes for ventilation, and the vibrating membrane in the dynamic head has no direct contact with the irradiated surface. The dynamic head unit is framed with a soft elastic protective cover, which greatly reduces the sound and vibration level transmitted to the operator's hands. The anterior part is made of silicone for a comfortable adherence to the chest.

When the vibroacoustic transducer is activated, the vibrating membrane produces fluctuations in air pressure. Sealing nozzle between the membrane and the irradiated surface form a chamber of high acoustic pressure. Due to the relatively high frequency and sufficiently high amplitude vibrations of the membrane, the vibrations can be effectively transmitted to and within the patient's chest even in the absence of an airtight seal. In this regard, the vibroacoustic transducer can be applied through cloth pads, medical sheets, napkins and clothing.

In a further embodiment, the system may include an attachment which consists of two arms connected by a hinge mechanism, in which transducers are located in the two arms ("Vibrowrap"). Special closed-type heads are used as the transducers which has a design similar to vibro-transducers or bass shakers. The Vibrowrap is fastened to the upper regions of the patient's chest, and can therefore also be used for bedridden patients or those with chest wall injuries. The configuration of the Vibrowrap is such that it covers less than half of the patient's chest. The inner surface of the Vibrowrap is covered with a layer of silicone to ensure a dense and comfortable adherence to the surface of the chest. To reduce the risk of bacterial contamination, all surfaces of the Vibrowrap are made of materials which are easy to clean and can be disinfected. Depending on the age and built of the patient, the number of transducers and their corresponding output capacity may be adjusted accordingly.

In another embodiment, the Vibrowrap can be configured in such a way as to allow the vibroacoustic effects to be applied to one lung when the patient is placed in a lateral position.

In another embodiment, the Vibrowrap can be fastened to the patient's back and the vibroacoustic effects can be applied to both lungs on the same plane when the patient is resting in a prone position

To reduce ambient noise and control the quality of the vibroacoustic effects, the system may further comprise in-built optical sensors. These sensors can be installed in the vibroacoustic transducers or in the arms of the Vibrowrap. An automatic pause is activated when the optical sensors detect an absence of contact with the patient's body. This feature further prevents the transducers from premature wear when the system is in an idle state.

In another embodiment of the invention, vibroacoustic transducers are used in combination with the Vibrowrap to increase the area of exposure and/or provide a greater amplitude of pressure fluctuations in the lungs. A larger contact area with the patient's chest reduces any discomfort caused by high pressure concentration.

In the preferred embodiment of the invention, the system is equipped with at least three types of patient profiles and at least ten pre-installed treatment program or predetermined settings or modes for the treatment of different pulmonary diseases and/or conditions, as may have been described above or otherwise.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions, considered together with the accompanying drawings will provide a more detailed explanation of the invention. The components in the drawings are not necessarily drawn to scale, with emphasis instead being placed upon clearly illustrating the principles of the present invention, wherein:

• Fig. 1 is an overview of the general principle of operation of the system.
• Fig. 2 is a flow diagram of an alternative embodiment of the system in Fig. 1. This diagram can be expanded or simplified, according to the various options selected.
• Fig. 3 shows an overview of the approximate frequency emphasis of a particular treatment program for the prevention of pulmonary complications.
• Fig. 4 shows the changes in the frequency of the modulating signal over time.
• Fig. 5 is a cross sectional view of one embodiment of the vibroacoustic transducer in accordance with the present disclosure.
• Fig. 6 is a cross sectional view of one embodiment of the Vibrowrap in accordance with the present disclosure showing the use of 3 tactile transducers in each arm of the Vibrowrap.
• Fig. 7 is a cross sectional view of one embodiment of the vibroacoustic transducer which shows the surface of the detachable sealing nozzle having a recess for placement on the side of the patent's chest.

DETAILED DESCRIPTION

The present invention provides a vibroacoustic system which generates electric signals of a variable or floating frequency between 20 Hz to 300 Hz, which are converted by transducers into acoustic waves (i.e. sound) and vibrations. The amplitude, wave shape, range and frequency of the signals can be varied according to the patient's requirements. The system identifies the type of vibroacoustic transducer connected to the main unit, and automatically adjusts the signal characteristics, output power and intensity of exposure as required.

The present invention further allows for structural configuration of the settings to enable the system to be used effectively in each patient's case as described hereunder. At the start of the treatment session, the operator is able to select the age category and body type of the patient. Depending on the selected age category, the system automatically limits the maximum output power, thus providing additional safeguards against excessive vibroacoustic exposure to young children or patients above the age of 60. The intensity of exposure is also automatically adjusted depending on the physique of the patient. For example, the intensity is reduced for patients with hyposthenic body types, whereas the intensity of exposure increases accordingly for patients with a higher body mass index.

After the appropriate treatment program has been selected, the system allows the operator to further control and regulate the intensity of exposure within the framework of pre-set limits, which have been determined by age and body type.

An embodiment of the system as shown in Fig. 1 consists of a main unit 10 which further comprises of a control panel 11, program archive 12, Waveform Generator 13, and two controllable power amplifiers (AMP A) 17 and (APM B) 18. The main unit is connected to a set of transducers 21 and 22. Optionally, Synchronisation Module 29 can be used in the system, which optronises the treatment program with the patient's breathing. The synchronisation of certain treatment programs with the patient's breathing may increase the effectiveness of the treatment.

When in use, the Microprocessor Control Unit (MCU) 14 generates a sequence of electrical or analog signals based on the program selected on the control panel 11. These signals are then synthesised by the DDS (Channel B) 15 and DDS (Channel A) 16 and modulated to produce sinusoidal signals of the required form and frequency. The signals arrive at the input terminals of the power amplifiers (AMP A) 17 and (AMP B) 18 and are boosted according to the amplification factor of the specific program. This ensures that the signals are sufficiently amplified to the levels required for the efficient operation of the transducers. The amplified signals then pass through the protection modules 19 and 20 before arriving at the transducers 21 and 22. The protection module is designed to disconnect the outputs of the main unit 10, in the event of malfunction. The transducers 21 and 22 then convert the signals into acoustic waves and vibrations 23 and 24.

The system has two independent channels, and the signals arriving at the transducers 21 and 22 may differ from each other, depending on the patient profile, pathology and treatment program selected.

The operation of the system is controlled by the Central Processor Unit (CPU) 26 located in the control panel 11. The user inputs are supplied to the CPU and operational status is displayed to the operator via the touchscreen display 25.

Fig. 2 is a flow diagram which shows the major components in the control panel referenced as 11 in Fig. 1. The touchscreen display 25 allows the operator to select the required program from the pre-installed programs stored in the program archive 12, navigate the main menu, and input commands to control and operate the system. For instance, the maximum output capacity level can be lowered or otherwise adjusted for children and elderly patients or those who are recovering from surgery. This safety feature reduces the possible adverse effects of vibration on the chest and organs for such patients. Further, patient records and treatment information may be stored in the Solid State Drive (SSD) Storage 27 to create a patient database. To begin treatment, an appropriate program is selected from one of the pre-installed programs stored in the program archive 12 using the touchscreen display 25.

The Synchronisation Module 29, which provides synchronization with the patient's breathing, consists of a Breath Detector 30 that detects the respiratory phases by signals from the Impedance Meter 31 and the Air Pressure Meter 32. The Impedance Meter 31 is connected to sensors 34 that measure the impedance of the chest muscles that determines the phases of breathing. A pressure sensor 33 is connected to the Air Pressure Meter 32, which is further connected to the breathing circuit of a ventilator (not shown). This sensor is only used on patients connected to the ventilator.

The graph in Fig. 3 shows the approximate frequency emphasis when the program for prevention of pulmonary complications is selected. The y-axis in Fig. 3 indicates the percentage of the total duration of treatment, while the x-axis measures the frequencies of the wave emitted by the system. Fig. 3 shows that during treatment, wave frequencies from 20 - 40Hz are most commonly produced as compared to wave frequencies above 60Hz.

Acoustic waves with lower frequencies between 20 - 60Hz are able to penetrate the lungs most deeply and ensure that the alveoli and tracheobronchial tree are kept open. Therefore, such wave frequencies between 20 - 60Hz are effective for treating ARDS, ALI and severe pneumonia.

Acoustic waves with higher frequencies between 61 - 240Hz are used to treat chronic obstructive pulmonary diseases as the frequency range coincides with the resonant frequency of the bronchial walls and tracheobronchial tree. As a result, the vibroacoustic effects produced are able to penetrate deep into the lungs to cause intensive vibration of the bronchi, and thereby encourage drainage of fluids in the lungs and interstitial tissues.

The system is further able to generate high-frequency acoustic waves between 241 - 300Hz, which do not penetrate into the greater depth of the thoracic segment. Such high-frequency waves are produced less often than the other types of waves frequencies. Nevertheless, they are still effective for mucociliary clearance of the smaller bronchi, especially for patients with severe conditions in the intensive care unit.

Fig. 4 shows the change in frequency in a fragment of the modulating signals when the program for prevention of pulmonary complications is in operation. This particular program uses a combination of fast and slow modulations for patients that require resuscitation. The graph in Fig. 4 illustrates the intervals of rapid changes in frequency over a period of 25 seconds.

For lower frequency waves between 20 - 60Hz, slow modulations are effective for treating severe pulmonary restriction, ARDS and severe forms of pneumonia, whereas moderate modulations of these lower frequency waves are used for the treatment of pulmonary edema and perfusion-type respiratory failure.

As for higher frequency waves between 61 - 200Hz, slower modulations are used to treat acute brocho-obstructive disease and bronchial asthma. On the other hand, rapid modulations of such higher frequencies waves are more effective in treating mild pneumonia.

Fig. 5 is a cross sectional view of one embodiment of the vibroacoustic transducer 500 in accordance with the present disclosure.

The handheld vibroacoustic transducer 500 comprises of a compression-type dynamic head contained in a plastic housing 512 and framed with a soft elastic protective cover 511. A plurality of holes in the plastic housing 517 on the back part of the vibroacoustic transducer provide an opening for air outlet and ventilation. The vibrating membrane 513 in the dynamic head is made of plastic and has no direct contact with the irradiated surface. A protective grille 514 installed in front of the membrane further prevents accidental contact with the vibrating membrane. The front part of the transducer consists of a silicone seal 515 which can be removed for the purposes of cleaning and disinfecting the system.

The optical sensor 516 detects whether or not the vibroacoustic transducer is in contact with the patient's body. When the optical sensors detect that there is no contact between the patient and both transducers, the message is transmitted to the CPU 26 which temporarily deactivates the transducers by preventing the signals from reaching the transducers. This results in an automatic pause, and which is indicated on the touchscreen display 25. The procedure resumes when there is contact with at least one of the transducers.

The vibroacoustic transducer 500 is connected to the main unit 10 via insulated flexible cables within (not shown), which enables a wide range of motion without having to move the main unit. The vibroacoustic transducer is held by the operator and manually applied to the surface of the patient's chest. It is preferable to protect the front part of the vibroacoustic transducer with protective disposable covers, made of materials such as polyethylene, before each treatment, to reduce any risk of bacterial contamination between patients.

There are several types of vibroacoustic transducers available for different age categories of patients. For example, child vibroacoustic transducers are specially configured for infants and young children while the universal vibroacoustic transducers are designed to be used on adults and children above the age of three.

The universal vibroacoustic transducer designed for an adult patient has a diameter of approximately 10 cm, and the amplitude of pressure fluctuations, when pressed to the surface of the chest at maximum capacity, can reach up to 70-75 mbar. As this amplitude may be insufficient for effective treatment in most cases, it is therefore preferable to use both transducers simultaneously to increase the area of exposure and total output capacity, while minimising any discomfort caused to the patient.

The child vibroacoustic transducer are of a smaller dimension, have a smaller effective surface area and a lower output capacity than the universal vibroacoustic transducer. The diameter of the child vibroacoustic transducer is generally approximately 7-8 cm. Despite the smaller surface area, the child vibroacoustic transducer is nevertheless still able to generate sufficient pressure of up to about 60 mbar, when it is operating at maximum power. Child vibroacoustic transducers specially designed for younger children under the age of one have an even smaller diameter of approximately 4-6 cm and generate lower pressure of no more than 35 mbar.

In some embodiments of the invention, the vibroacoustic transducer may comprise a quick-release detachable and replaceable sealing nozzle. The shape and elasticity of the front surface of the sealing nozzle may differ to allow for easy placement on the surface of the patient's chest. For example, a recess created on the front surface of the sealing nozzle 702 allows the vibroacoustic transducer to be applied to the sides of the patient chest. The quick-release mechanism 701 may be made of plastic snaps or neodymium magnets which allows the sealing nozzle 702 to be easily separated from the plastic housing of the vibroacoustic transducer and replaced.

In an alternative embodiment of the invention, the Vibrowrap 600 can be connected to the main unit 10 of the system through a cable instead of the vibroacoustic transducer(s). Unlike the vibroacoustic transducer, the Vibrowrap 600 produces a narrower frequency range and is fastened to the patient's chest using elastic straps.

Fig. 6 is a cross sectional view of one embodiment of the Vibrowrap 600 which consists of two arms 611 and 612 connected by a hinge mechanism 613. A plurality of tactile transducers 614 are embedded on a flexible rectangular base located in both arms. Depending on the age and build of the patients, the number of transducers and their overall dimensions and capacity can be adjusted accordingly. The inner surface of the Vibrowrap 600 is covered with a layer of silicone 615 to ensure a dense and comfortable adherence to the surface of the chest. The outer surface 616 may be made of artificial vinyl leather or medical leatherette. All surfaces of the Vibrowrap are made of material which are easy to clean and can be disinfected to reduce the risk of bacterial contamination

The configuration of the Vibrowrap is such that it covers less than half of the patient's chest. The Vibrowrap is fastened to the upper regions of the chest, and can therefore also be used for bedridden patients or those with chest wall injuries. A child-friendly or child Vibrowrap is also available for the treatment of children.

Claims (6)

1. A system for treating restrictive pulmonary diseases, the system comprising:

   a main unit comprising a waveform generator (13) for generating electric signals modulated to produce sinusoidal signals of a wide frequency range of about 20 Hz to 300 Hz, a control panel (11), and power amplifiers (17,18) for amplifying the modulated sinusoidal signals, and

   at least one interchangeable transducer (22) connected to the main unit for converting said modulated sinusoidal signals into acoustic waves and vibrations and applying the acoustic waves and vibrations to the chest of a patient to achieve at least one, or a combination, of therapeutic effects selected from treating restrictive pulmonary disease, promoting opening of collapsed alveoli and preventing alveolar deflation,

   characterised by

   a synchronisation module (29) for synchronising the acoustic waves and vibrations with the patient's breathing to increase effectiveness of treatment by increasing the intensity of the waves and vibrations at the moment of inhalation and reducing their intensity at the moment of exhalation; and

   at least one protection module (19) for disconnecting the output of the main unit from the or each transducer (22) in the event of a malfunction of the system.
2. The system of Claim 1, wherein the synchronisation module further comprises:

   a breath detector (30);

   an impedance meter (31);

   an air pressure meter (32); and

   a plurality of sensors (33,34),

   wherein the breath detector detects respiratory phases by signals from the air pressure meter (32) and the impedance meter (321), the sensors (34,33) are coupled to the impedance meter for determining breathing phases, while the air pressure meter is coupled to a breathing circuit of a ventilator, for maximising effectiveness of treatment while minimising exposure of damaging other organs to vibration effects.
3. The system of Claim 2, further comprising:

   a microprocessor control unit (14) for generating electrical or analog signals based on the program selected on the control panel (11), which signals are synthesised and modulated to produce sinusoidal signals of the required form and frequency; and

   a pair of input terminals coupled to the power amplifiers (17,18) for boosting the sinusoidal signals in accordance with the amplification factor of a specific treatment program,

   wherein the synchronization module (29) provides feedback on output capacity levels from the ventilator to the microprocessor control unit.
4. The system of Claim 3, wherein the signals are modulated to cover all frequencies within the range for treatment at specific areas in lungs.
5. The system of Claim 1, further comprising at least one optical sensor (516) for detecting whether the at least one transducer (22) is in contact with the patient's body, wherein the at least one transducer (22) is safely deactivated resulting in an automatic pause if there is no contact with the patient's body before automatically resuming when there is contact again.
6. The system of Claim 5, further comprising a wrap-like means (600) having a plurality of vibro-transducers (614) based on the principles of bass-shakers positioned within two flexible rectangular bases (611,612) connected by a hinge mechanism (613), coupled to and covers less than half of the patient's chest, wherein the number of transducers and the corresponding output capacity may be adjusted according to the age and build of the patient.