WO1997028837A1

WO1997028837A1 - Rebreathing device

Info

Publication number: WO1997028837A1
Application number: PCT/GB1997/000377
Authority: WO
Inventors: Antonios Camille Zamar
Original assignee: Antonios Camille Zamar
Priority date: 1996-02-12
Filing date: 1997-02-11
Publication date: 1997-08-14
Also published as: EP0883416A1; AU1729997A; GB9602779D0

Abstract

A mask for use with panic attack patients which are, or might be, hyperventilating consists of a rim section to which is attached a bag made of a material impenetrable to the passage of air, the rim can be sealingly held against the face around the patient's nose and mouth so the patient exhales into the bag and inhales only the air in the bag which has an increased carbon dioxide content due to rebreathing. The mask is angled so that in use the patient should have a clear field of vision allowing maximal vision and subsequent sense of control of one's environment.

Description

REBREATHING DEVICE

The present invention relates to a mask, particularly it relates to a mask useful for controlling hyperventilation.

A significant proportion of the population suffer from panic attacks. Panic attacks consist of physical, psychological and behavioural components. Physical symptoms include hyperventilation, palpitations, sweating, tremor, dizziness and "funny" abdominal sensations. Psychological symptoms are fear of death and extreme anxiety, which tend to exacerbate the panic attack, and severe panic attacks can lead to incapacity and fits and cause acute distress in the person suffering such an attack. Behavioural symptoms include avoidance of, for example people, tasks, places and can lead to running away from situations and other behaviour considered "awkward" or even anti-social. Various theories have been put forward for the cause of panic attacks including genetic, hormonal, cerebral, respiratory and neurotransmitter malfunctions. Psychological, cognitive and behavioural theories have also been proposed.

Research has indicated that hyperventilation is a central feature in the pathophysiology of panic attacks and panic disorders. Panic patients have been shown to be chronic hyperventilators who also acutely hyperventilate during spontaneous and induced panic. Hyperventilation induces hypocapnia (low CO₂) and alkalosis lead to decreased cerebral perfusion, dizziness, confusion and derealisation (things feeling unreal). Thus on one hand hyperventilation can lead to panic attacks and on the other hand panic attacks are characterised by hyperventilation which then aggravates fear and panic, leading to a vicious circle.

Breathing control as a treatment for panic was shown to be effective. This aims at slowing breathing and reducing CO₂ loss. Traditionally paper bags have been used to control panic attacks. The purpose was for the patient to breathe in to the paper bag to prevent CO₂ loss which should either abort an attack at the onset or prevent the aggravation of symptoms through CO₂ loss and terminate the attack. The paper bag is held over the patient's mouth and nose so the patient breathes into the paper bag and rebreathes the air from the bag, which is supposed to increase the amount of CO₂ in the patient's bloodstream and thus control the symptoms of the panic attack and abort the panic attack, or at least prevent its aggravation by the relative reduction of CO^. Paper bags of the appropriate size, when they are available suffer several disadvantages, they do not seal well around the nose and mouth allowing loss of CO and they allow loss of CO₂ by permeation of CO₂ through the bag. It has been shown that with paper bags, even when they are well held around the nose and mouth the level in the paper bag will plateau out at a certain level which is below the level which would be most helpful and it will not rise above this level. In order to reduce the permeation of the CO₂ through the bag it has been proposed to treat the paper bag with oil and although this does improve the performance of the bag, leakage may occur around the nose and mouth. In actual situations it is clearly a cumbersome operation to expect the person to start soaking a paper bag in oil and pre-soaked bags have practical difficulties which are related to both volume and hampering vision. In practice the paper bag needs a capacity sufficient to enable the patient to exhale a large volume of air and bags of a capacity of at least four litres and preferably larger are preferred. Bags of this size tend to block the vision of the patient which can increase the sense of panic and are also aesthetically unacceptable.

I have now invented a mask which can be used in panic attacks which reduces and/or overcomes these difficulties.

According to the invention there is provided a mask, the mask being adapted to fit over the nose and mouth of a patient so as to prevent ingress and egress of air around the edge of the mask in contact with the patient and comprising a sealing rim for sealingly engaging the mask around the nose and mouth of the patient and a bag connected to the mask for receiving air exhaled by the patient and returning the air to the patient during inhalation.

Preferably the bag should be made of a flexible material which is substantially impervious to the air, so that CO cannot escape through the walls of the bag, in general inert plastics materials such as polyolefins and substituted polyolefins e.g. polyethylene, polyproplyene and their copolymers, polyvinyl chloride, polyesters etc. can be used. In general elastic rubber type materials are not desirable as they tend to recoil, pressurise and put pressure on the patient's respiratory system. For adults the bag should have a capacity of at least four litres and can be larger e g up to six litres, for children a smaller capacity can be used In general bags of a capacity of one to six litres are suitable

There should not be any other apertures in the mask and the mask should not be attached to any other devices such as air or oxygen supplies

The sealing rim is preferably made of a material which fits comfortably on a patient's face and does not cause discomfort and is easy to keep clean etc in general a flexible plastics material can be used

When not required the bag is preferably able to be folded flat into a compact parcel and, in a preferred embodiment, the bag folds and can be placed inside the rim, which is then sealed to provide an easily portable mask which can be carried around by a potential sufferer

The mask has particular application in controlling hyperventilation/ panic symptoms but is also use for controlling some types of hiccups The mask is readily portable and the bag is completely sealed against air entering the mask from outside and against air escaping from the mask and so allows the level of CO in the air being rebreathed to rise to high levels not otherwise achievable by alternative methods, this means the level of CO in the blood stream can more quickly and effectively rise to a level which reduces or alleviates hiccups Using the mask of the invention levels of CO-} in the blood should be maintained between 35-45mm Hg without compromising the total body CO₂ reserve This is only achievable by raising the CO level maximally within the mask (above 40mm Hg) without leakage or with very minimal leakage With paper bags it has not been generally possible to achieve levels over 45mm Hg. Oily bags have achieved levels of 57mm Hg but may not be suitable for panic patients as they hamper vision and may increase the sense of loss of control

In use the patient can simply offer the mask up to the face to cover the nose and mouth and press the mask against the face so as to seal the mask against the face around the mouth and nose The bag is preferably permanently connected to the rim and made of non leaking material.

The mask can optionally include a band for fitting around the head of a patient but normally it is preferable for the patient to hold the mask in place.

The invention is illustrated in the accompanying drawings, in which:

Fig. 1 is a side elevation of a mask on a patient's face with the bag in its stowed configuration:

Fig. 2 is a side elevation of the mask on the patient's face with the bag in its deployed configuration; and

Fig. 3 is a front elevation of the mask with the bag in its stowed configuration

As shown in the drawings, a mask 1 has the generally triangular shape when viewed from the front, having a concave portion 2 for receiving the nose 3 and mouth 4 of patient 5.

The mask 1 can be made of transparent flexible material such as a rubbery plastics material which preferably has some flexibility in order to aid comfort and fitting to the face of the patient 5.

Around that portion of the mask 1 which fits to the patient's face, there is provided a seal 6. The seal 6 is made of a flexible material so as to aid sealing of the mask 1 to the patient's face around the nose 3 and mouth 4. The seal 6 may be fixed to the mask 1 or, as an alternative the seal 6 may be integral with the body of the mask 1.

Connected to the portion of the mask 1 remote from the seal 6 is a container 7 which contains a bag 8 when the mask is not in use. The container 7 consists of a rigid circular ring 9 which encircled the front end of the mask 1 and a lid 10 which is connected to the ring 9 by a hinge 1 1. A clip 12 is provided on the opposite side of the lid 10 for engagement with the ring 9 in order to allow the lid 10 to be clipped to the ring 9 in order to close the container 7. The bag 8 is connected at its open end through the ring 9 to the mask 1 in an air tight manner. The bag 8 is made of a very flexible material such as a high density polyethylene. The bag 8 can be folded into the container 7 when not in use, which makes the whole mask readily transportable and also serves to protect the bag during transport. The bag 8 is entirely sealed against the atmosphere so that air cannot escape from or enter the bag 8 other than to or from the patient. Along the length of the bag there are longitudinal folds 14 to allow for maximal expansion with the least use of volume and facilitates the ability of the bag to fold flat when not in use.

When the patient 5 is undergoing a panic attack, or is otherwise hyperventilating, the patient 5 opens the lid 10 of the container 7 and pulls out the bag 8. The mask 1 is then pressed up against the patient's face so that the seal 6 engages over the nose and mouth against the patient's face. The patient 5 then breathes through the mask 1 into the bag 8 during exhalation and rebreathes the air from the bag 8 during inhalation. Pressing the mask 1 against the face ensures that no air can enter the bag 8 or mask 1 from the atmosphere, this will maximise the build up of CO₂ in the air in bag 8 which is inhaled by the patient 5. The connection of the bag 8 to the mask 1 is also air tight, again to prevent air from entering the bag 8 or mask 1 from the atmosphere. The patient will hold the mask 1 against his face for perhaps a few minutes so as to allow time for the CO levels to build up in the inhaled air and then in bloodstream so as to prevent hyperventilation and so prevent a panic attack from starting or at least prevent aggravation of a panic attack which would otherwise occur if the patient were allowed to hyperventilate. Naturally, the patient can easily remove the mask 1 from his face if he feels distressed, but the patient should be urged to keep the mask against his face until the panic symptoms have subsided. The bag should clearly be of sufficient volume to enable there to be enough oxygen in the inhaled air. Panic attacks can usually last from five to twenty minutes and it is expected that the mask 1 need be held against the face for perhaps only a few minute in order to prevent the panic attack from occurring or at least to reduce the effect of the panic attack.

The mask 1 may be fitted with an elastic head band 13 for securing the mask to the face. However it is preferred that the patient learns to hold the mask 1 to the face, rather than rely on the head band, as this will encourage the patient to control panic attacks and hopefully act quickly enough to prevent onset of a full panic attack. Holding the mask against the face prevents any risk of lack of oxygen if the patient is unable to remove the mask held on by the band.

The mask 1 of the present invention also has application in controlling some types of hiccups. Following abdominal surgery or any other intra-abdominal diaphragmatic irritation or renal failure hiccups can occur. The mask 1 of the present invention can be used to control or alleviate such hiccups, perhaps in conjunction with medication if necessary and is used in the same manner as described above for controlling hyperventilation and panic disorders. Preferably the mask 1 is disposable to prevent bacteria build up in the bag 8 through use and the patient can use a new bag after each use. The mask and bag of the invention can be made of materials which are sufficiently inexpensive to permit this.

Claims

1 A mask adapted to fit over the nose and mouth of a patient so as io prevent ingress and egress of air around the edge of the mask in contact with the patient and comprising a sealing nm for sealingly engaging the mask aiound the nose and mouth of the patient and a bag connected to the mask for receiving air exhaled by the patient and returning the air to the patient duπng inhalation

2 A mask as claimed in claim 1 which is so constructed that when u is held against the face of a patient the bag is positioned in a downward direction so as to allow a clear range of vision for the patient

3 A mask as claimed in claim 1 or 2 in which the bag has a capacity of one to six litres

4 A mask as claimed in any one of claims 1 to 3 in which the bag is made of a polyolefin or a substituted polyolefin

5 A mask as claimed in any one of the preceding claims in which the mask and bag are have no other aperture other than the aperture which fits over the face and nose of a patient and cannot be connected to any other device

6 A mask as claimed in any one of claims 1 to 5 in which, when not required, the bag is able to be folded flat into a portable compact parcel

7 A mask as claimed in claim 6 in which the bag can fold along longitudinal folds and can be placed inside the nm, which is then closed to provide an easily portable package

A mask as hereinbefore described with reference to the drawings