IE20180034A1

IE20180034A1 - Snorkel ventilating airway and bite block

Info

Publication number: IE20180034A1
Application number: IE20180034A
Authority: IE
Inventors: Mcdonald Neil
Original assignee: Airway Medical Ltd
Priority date: 2018-02-21
Filing date: 2018-02-21
Publication date: 2019-11-13
Also published as: IE87067B1; WO2019162024A1

Abstract

The invention provides a multifunctional airway device adapted for insertion into the mouth of a patient, said airway device comprising:(a) an elongate, tubular oral airway body of substantially elliptical or substantially circular cross-section, the airway body having: a substantially straight section, the proximal end of which is adapted to function as an integral bite-block and the distal end of which is narrowed and provided with a distal tip for facilitating placement of the airway device; and a central channel for the passage of oxygen and anaesthetic gases and for accepting an endoscope; (b) a connector for facilitating attachment of breathing or anaesthesia equipment thereto, wherein the connector is attached to the proximal end of the airway body; and (c) an intraoral flange which is a one piece construction of polyvinyl chloride, polyurethane, silicone or other elastomeric material possessing the correct properties of elasticity, stiffness, resilience and flexibility such that the flange is flexible, self-retaining and self-sealing and has a concave, substantially oval shape with a central aperture for receiving and firmly gripping the airway body in which the elasticity of the flange enables it to be placed anywhere along the shaft of the airway and thereby vary the length of the intraoral part of the airway or for maximal intraoral length in a retaining groove on the proximal end of the airway body, wherein the airway device acts as a snorkel ventilation airway and bite-block. <Figure 1A>

Description

SNORKEL VENTILATING AIRWAY AND BITE BLOCK The present invention relates to multifunctional combined airway and bite-block devices, in particular to an oral airway and bite block device with a detachable intraoral self5 retaining and self-sealing flange and an oropharyngeal airway and bite-block device with a detachable intraoral self-retaining and self-sealing flange. More particularly the invention relates to a snorkel ventilating airway and bite block.

Maintenance.of a patient’s airway is of paramount importance during anaesthesia and 10 when patients undergo medical procedures when sedated. Difficulties or failures in managing the airway are the major factors underlying morbidity and mortality relating to anesthesia and procedural sedation.

At induction of general anaesthesia, the anaesthetist has to maintain a patent airway and 15 at the same time seal the face mask around the patient’s mouth and nose with or without an oropharyngeal airway (OPA). Bag Mask Valve (BMV) ventilation is difficult in more than 5% of patients and impossible in 0.16%. In those cases, where the anaesthetist cannot maintain an adequate airtight seal during BMV ventilation, for example when the patient has facial hair, such as a beard or moustache, is edentulous (lacking teeth), obese, has 20 facial burns or other facial skin condition or trauma, the anaesthetist would typically have to rush general anaesthetic induction by prematurely placing either a Laryngeal Mask Airway or Endotracheal tube. BMV ventilation is also difficult for an anaesthetist with small hands looking after a big patient and some patients are mask phobic (e.g. due to claustrophobia) and will not tolerate a face mask for pre-oxygenation prior to induction of 25 general anaesthesia.

A number of ventilation systems have been proposed as alternatives to the use of a face mask. For example, US 4,270,531 discloses a U-shaped bite block fitted about the exterior of an airway tube having the same general configuration as conventional 30 oropharyngeal tubes, such as the Guedel airway. The bite block has vertically separated upper and lower tooth- or gum-engaging surfaces and a peripheral rim to fit against the outer surfaces of the teeth or gums of the patient and inside the lips. When inserted into the patient's mouth, the posterior tube portion extends above the tongue to the upper throat, preventing the tongue from blocking the throat. There are several disadvantages 35 to this. For example, it would most likely have to be positioned like a Guedel airway, i.e. -2upside down first. As the device is bulkier than a Guedel airway, this would be difficult. There would be a considerable risk of trauma to soft delicate pharyngeal structures and the bite block could cause hard trauma to teeth. Additionally, the U-shaped bite block is contoured to the shape of the upper and lower jaws. The opening between the upper and lower jaws is much greater than that covered by this device. During positive pressure breaths, gas escapes from between the jaws and behind or lateral to the device. The mouth can only be sealed by applying external pressure over the cheeks and lips. Additionally the device disclosed in US 4,270,531 is not capable of facilitating fibreoptic intubation (FOI), i.e. it is not the correct shape for functioning as an airway for FOI nor does it allow for administration of 100% oxygen and positive pressure breathing during FOI.

WO 2005/097245 discloses a respiratory mask having an intraoral mouthpiece configured to fit the natural shape of the gums and inside of the lips of persons to be ventilated. However, this intraoral mouthpiece is not configured to seal the mouth opening, for example during positive pressure breathing. The intraoral mouthpiece is smaller than the opening between the upper and lower jaws. During positive pressure ventilation, gas escapes around the posterior margins and pushes between the mouth piece and the cheeks and attempts to escape from the corners of the mouth. A seal is achieved by applying external pressure over the cheeks. In addition due to it's contoured shape the intraoral mask tends to pop out of the mouth and so is not self-retaining. The intraoral mouthpiece has a central orifice which feeds into a tubular extension having a reinforced collar. The collar allows a healthcare provider to handle and position the respiratory mask. A flexible oropharyngeal airway may be used in combination with the intraoral mouthpiece either by attachment with a recess in the inner wall of the intraoral mouthpiece or by slidable insertion through the tubular extension. This is not intuitive and may pose problems for the occasional user. The respiratory mask disclosed in WO 2005/097245 cannot act as a bite block. Additionally, it cannot be used to facilitate FOI or upper gastrointestinal endoscopy nor to allow for administration of 100% oxygen and positive pressure breathing during FOI.

Many diagnostic procedures such as bronchoscopy, upper gastrointestinal endoscopy and transoesophageal echocardiography are performed under conscious or deep sedation. A bite-block is placed between the patient's upper and lower teeth to prevent the patient biting down on the endoscope. The commonly used bite-blocks are difficult to keep in -3place, are not self-retaining and require either or both to be constantly held in position or secured with a strap around the patient’s neck. In addition some bite-blocks have an inner flange which sits inside the upper and lower teeth the purpose of which is to stop the biteblock from falling out of the mouth. Because of this inner flange and also because of wide variation in human dentition, initial placement is often difficult and also the bite-block frequently falls out of place during the endoscopy procedure and subsequent replacement is difficult. The patient breathes room air supplemented with oxygen administered via nasal cannulae. With consciousness obtunded due to the effects of anaesthetics, opioids or benzodiazepines protective airway reflexes (such as coughing) are impaired, airway patency may be lost and sometimes there is a loss of a regular breathing pattern. If airway difficulties occur the procedure is suspended, the bite-block removed and the patient resuscitated using a face mask and a breathing circuit delivering 100% oxygen.

Below are three patent publications relating to endoscopy masks. All require straps, are cumbersome to use, hard to get a seal between face and mask, and are claustrophobic for a lot of patients 1. ) WO 2014134048 (Michelle Eisenberger) endoscopy mask (Germany) 2. ) WO 2014078034A1 Basavana Gouda Ventilating bite block. This consists of a face mask secured by a strap around the patient’s head with self sealing apertures for the endoscope and a breathing circuit; incorporates a bite block. It has to be secured with a strap. The cuff has to be inflated in an attempt to achieve a seal and it is claustrophobic; 3. ) US 5431158 (Christopher F. Tirotta). This discloses an endoscopy face mask which fits over nose and mouth. It needs a strap, is claustrophobic, and is difficult to get a seal.

Despite the advances of the prior art described hereinabove, there is a need to provide an airway device which is a combined bite-block and airway for preoxygenation and induction of general anaesthesia and for endoscopic procedures performed in sedated patients which is self-retaining and self-sealing, connects to a standard breathing circuit and which allows for an endoscope to be passed there through via a self sealing aperture, allows for 100% oxygen to be administered during the procedure, helps to keep the patient’s airway patent, should apnoea occur apneic oxygenation significantly prolongs the time before dangerous hypoxaemia occurs, facilitates continuous capnography monitoring, and -4should airway difficulties occur allows positive pressure ventilation to be delivered through it.

It is an object of the present invention to provide a device and method that seek to alleviate the aforementioned problems. This invention is an improvement over the airway devices disclosed in WO 2016/034572 published on 10th March 2016 and the entire contents are incorporated by reference.

The present invention is more particularly defined in the appended claims which are incorporated into this description by reference.

Thus according to a first aspect, the invention provides a multifunctional airway device as an oral airway device adapted for insertion into the mouth of a patient, said airway device comprising: (a) an elongate, tubular oral airway body of substantially elliptical or substantially circular cross-section, the airway body having: a substantially straight section, the proximal end of which is adapted to function as an integral bite block wherein the distal end of the airway body substantially conforms to the front of the tongue but does not extend into the pharynx; and a central channel for the passage of oxygen and anaesthetic gases and for accepting an endoscope; (b) a connector for facilitating attachment of breathing or anaesthesia equipment thereto, wherein the connector is attached to the proximal end of the airway body and has a groove on its external surface, wherein the groove forms a circular channel for accepting the intraoral flange.

As used herein, the term "distal" as it refers to the elongate, tubular airway body refers to the part of the airway body which in use leads as the device is introduced into the patient’s mouth and is further from the clinician deploying the device, whereas the term "proximal" refers to the other end of the airway body which in use is nearer the clinician.

An airway device is also provided that can prevent and or treat "Difficult and Impossible Mask Ventilation.

An airway device is provided that is both self retaining and self sealing and helps to keep the patient’s airway patent for endoscopy that doesn’t require straps or to be held in position during normal use.

An airway device is provided that when used for endoscopic procedures such as upper gastrointestinal endoscopy, fibreoptic bronchoscopy and transoesophageal echocardiography allows the patient to be preoxygenated with 100% oxygen, helps to keep the patient’s airway patent and because 100% oxygen can be administered throughout the procedure should apnoea occur the safe apnoea period before dangerous hypoxaemia occurs can be significantly prolonged because of Apnoeic Oxygenation.

An airway device is provided that when used for endoscopic procedures such as upper gastrointestinal endoscopy, fibreoptic bronchoscopy and transoesophageal echocardiography makes the endoscopist’s job easier and as a consequence reduces the risk of damaging delicate oral structures because the patient cannot obstruct the central channel of the airway with his tongue and also because the endoscopist can direct the airway towards the pharynx thus facilitating passage of the endoscope into the oesophagus or larynx as indicated.

The flange is flexible, self-retaining and self sealing and having a concave shape and adapted to be placed with the concave side facing towards the mouth of the patient or concave away from the mouth of the patient and then snapped back into a concave shape facing the mouth of the patient but with the top and bottom of the middle section curved inwards towards the gums; and having a greater cross-sectional area than the mouth opening with each end being arrow shaped like the corner of the mouth when the mouth is open to aid placement.

The direction the self sealing, self retaining flange faces on the airway alters the shape of the flange and alters how easy or difficult it is to deform it. When placed on the airway concave towards the mouth, it retains it’s original shape and resists deformation to a greater extent than when mounted on the airway concave side facing away from the mouth and then manually pulling the flange so that it snaps into a concave shape facing the mouth. The clinician will make the choice based on the shape of the patient’s face. For patients with a typically masculine face, the clinician will face the flange with it’s natural concave shape facing towards the mouth and for patients with a narrow or more -6feminine shaped face, the clinician will mount the flange on the airway with it’s natural concave shape facing away from the mouth and pull it forward so that the flange snaps to a concave shape facing the mouth.

The flange has a reinforced rim around the perimeter which provides rigidity while allowing flexibility. A second rim surrounds the central aperture. The two rims and the concave shape of the flange resist deformation. The flange is a one piece construction of polyvinyl chloride, polyurethane, silicone or other elastomeric material possessing the correct properties of elasticity, stiffness, resilience and flexibility such that the flange is self retaining and self sealing. The elasticity of the flange allows the ends to be compressed between thumb and forefinger for placement inside the cheeks.

The elasticity of the flange also means the flange can be placed anywhere along the shaft of the airway and so vary the length of the intraoral part of the airway.

The flange is self-retaining inside the mouth because it’s cross sectional area is greater than the mouth opening and it is wider than the width of the mouth and projects laterally well past the corners of the mouth and the fibromuscular modiolus and it resists deformation.

The shape of the flange and whether the natural concavity faces towards or away from the mouth determines it’s resistance to deformation. When deformed by the cheeks, the central part of the flange maintains some of it’s natural curvature and so is directed inwards towards the gums and teeth which prevents it from protruding from beneath the top lip and because of it’s essentially flat shape along it’s long axis and because of it’s sufficiently high stiffness and yield strength it resists further deflection and so does not pop out of the mouth. In effect, the flange has a bending stiffness low enough to enable deflection by point load application for insertion, but stiff enough to limit the deflection when placed in the mouth of the patient where it has effectively a distributed load applied by the positive pressure and is also restrained by the mouth.

The flange is self-sealing because of its resilience, in that it is quickly and constantly trying to return to its original shape. In this way it forms a dynamic seal of the inside of the mouth in that it continuously follows variation in the surface of the mouth that it is sealing. Thus it continues to seal even when the mouth may undergo small changes in size and shape -7 during the different phases of the respiratory cycle. The chosen elastomeric material has a high elastic limit and doesn’t display plasticity in its working range.

The lips of the patient function as a purse string largely because of the bulk of the 5 orbicularis oris muscle and the fibromuscular modiolus just lateral to the corners of the mouth even when it is relaxed and not contracting. The rim around the perimeter of the flange and the curvature of the top and bottom of the middle section resists distortion and when in place in the vestibule of the mouth sits outside the orbicularis oris muscle and the fibromuscular modiolus and so retains the flange even during positive pressure breaths. 10 The flange is further supported in position in the vestibule of the mouth between the lips and cheeks and the gums and teeth by the airway device traversing and firmly gripped in the central aperture of the flange. A flange with an appropriately sized central aperture is required for each airway device. The cut-out in the midline at the top and bottom of the flange accommodates the top and bottom frenulum.

Between the perimeter rim and the rim surrounding the central aperture the flange is flexible. During normal breathing and positive pressure ventilation breaths, the flange seals the mouth opening by adhering to the soft moist and smooth inner mucosa of the cheeks and lips. The flange contributes to jaw thrust because it resists displacement. 20 When the flange is in position in the vestibule of the mouth it is forced by the cheeks to adopt the contour of the inside of the cheeks. In resisting displacement and because the upper jaw is fixed and not mobile, the flange exerts a pulling force on the lower jaw which helps to keep the patient’s airway patent. The intraoral flange does not seal the large opening between the upper and lower jaws but rather seals the mouth from the inside.

The width of the vestibule of the mouth is much greater than the width of the mouth opening and this allows for the width of the flange to be much greater than the maximum width of the mouth opening. Thus with the flange located in the vestibule of the mouth, the corners of the mouth and the fibromuscular modiolus are primarily responsible for 30 anchoring/ retaining the airway device in position.

In one configuration, the self retaining and seif sealing intraoral flange is detachable allowing for different sized flanges to be fitted to different sized airway devices. This allows for variation in patient anatomy. -8In another configuration the seif retaining and self sealing intraoral flange is fixed and not detachable on the oral or oropharyngeal airway.

The multifunctional airway device according to the invention makes the clinician’s job easier whether for anaesthesia or endoscopy, increases patient safety and results in basic airway management being easy to achieve for someone who is not an expert in airway skills.

Preferably, conventional nasal occluding means such as a nose clip are used in combination with the self retaining and self sealing flange to permit positive pressure ventilation of a patient when required. Alternatively, rather than a nose clip being used, a clinician’s assistant could pinch the patient’s nostrils closed.

In a preferred embodiment, the multifunctional airway device is a multifunctional oral airway device, wherein the distal end of the airway body substantially conforms to the front half of the tongue but does not extend into the pharynx. In an alternative embodiment, the multifunctional airway device is a multifunctional oropharyngeal airway device, wherein the curved distal end of the airway body substantially conforms to the curvature of the part of the pharynx between the soft palate and the upper edge of the epiglottis.

The curved oval-shaped fixed or detachable intraoral flange is adapted to fit between a patient’s gums and teeth and lips and cheeks. The airway body is adapted to pass through the central aperture of the intraoral flange.

The self retaining and self sealing flange has at least one axis of symmetry, preferably two axes of symmetry. In a preferred embodiment, the shape of the intraoral flange resembles7 an oval with triangular cut-outs at the top and bottom. It is arrow or triangular shaped at each end having a preformed or inbuilt concave shape.

In use, the intraoral self retaining and self sealing flange provides a substantially airtight seal between the airway body and the inside of a patient’s mouth. During gentle positive pressure breaths, gas emitting from the distal end of the airway pushes up against the flange increasing the sealing effect. Any leak of gas from the mouth during vigorous positive pressure ventilation can easily be sealed with finger pressure on the top and -9bottom lip in the midline below the nose. An airtight seal is provided even in the absence of teeth in a patient. This facilitates positive pressure ventilation where a good seal cannot be made between a face mask and a patient’s face, for example due to patient obesity, a skin condition, facial deformity, lack of teeth or the presence of a beard.

Because the device is self retaining and self sealing it is also "Hands Free". The airway body preferably has a hard internal surface, i.e. the airway body is preferably made of hard material on the inside, to maintain the lumen even if the patient bites down. Thus the proximal end of the substantially straight middle section of the airway body acts as an integral bite block. Preferably, the airway body is made of a polymer selected from among medical grade polyethylene, polypropylene, polyvinylchloride and polycarbonate, preferably polyethylene.

The underside of the straight middie section of the airway body is provided with a glottal surface to assist in preventing the tongue from obstructing the pharynx. The profile of the glottal surface is horizontal where the glottal surface is in relative position with the tongue.

The leading edges of the distal end of the airway body are rounded to minimise trauma to the anatomy, for example to minimise damage to delicate oral tissues. In the oropharyngeal airway device, the glottal surface (i.e. underside) of the distal end is provided with a rounded lip at the distal tip which aids placement of the device into a patient’s pharynx. The lip allows the device to slide over the patient’s tongue during placement minimising trauma to the tongue and oropharynx. The curved underside of the distal end of the airway body aids placement of the multifunctional airway device into the patient, as does the glottal lip, when present. The multifunctional airway device can thus be placed without turning it upside down first as would be required with a standard airway device, e.g. a Guedel airway, which has a sharp, straight and hard distal end which tends to catch on the tongue.

The airway body and intraoral self retaining and self sealing flange may each independently be made in different sizes to accommodate varied patient groups, such as infants, children, women, men and adults of different sizes. Preferably, the intraoral flange and airway body are each independently provided with a size identifier such as an integer from 1 to 5, e.g. 3. This size identifier represents a similar sizing system to the - 10Guedel and the LMA sizing system wherein size 1 is for an infant, 2 for a child, 3 for a small adult, 4 for an adult and 5 for a large adult.

The multifunctional airway device according to the invention is suitable for use in conjunction with breathing equipment such as a non-rebreathing Mapleson C circuit or a bag and valve type resuscitator. Additionally, the multifunctional airway device is suitable for use in conjunction with anaesthetic equipment.

The radius of curvature of the elongate curved airway body (see Figure 11) is preferably in the range of from approximately 20 mm to approximately 50 mm, e.g. 35.50 mm or 35.75 mm and the shaft has a third wall (from 5mm to 10 mm for rigidity. These dimensions vary depending on whether the device is to be used on an adult patient or a child patient.

In one embodiment, the multifunctional airway device is suitable for a child and has circular internal and external profiles, i.e. has a circular cross-section. In this embodiment, the internal diameter of the airway body is preferably in the range of from approximately 5 mm to approximately 40 mm, e.g. 11.75 mm. In another embodiment, the oral multifunctional airway device is suitable for an adult, is larger than the child-suitable version and has an elliptical cross-section. In this embodiment, the external conjugate diameter of the airway body is in the range of from approximately 15 mm to approximately 50 mm, e.g. 18.50 mm and the external transverse diameter of the airway body is in the range of from approximately 15 mm to approximately 50 mm, e.g. 23.50 mrm The internal diameter of the adult multifunctional airway device is sufficient to allow passage of the full range of endoscopes and transoesophageal echocardiography probes.

In one embodiment an angle piece connector with a working channel, which can accommodate the full range of endoscopes and transoesophageal echocardiography probes and closed at it’s proximal end with a self-sealing aperture, is factory fitted to the connector of the adult oral multifunctional airway device.

The diameter of the connector also varies for the adult and child version.

According to International standards, all breathing circuit connectors must be either 22 or 15 mm diameter male or female. The internal diameter of the adult connector is 22 mm whereas the external diameter of the child version is 15 mm. The reason for the -11difference in cross-section between the adult and child versions is in the method of interfacing with the standard breathing aids. By "standard breathing aids" is meant breathing aids conforming to the ISO standard for anaesthetic and breathing aids. The child size connectors are of a reduced outer diameter as they are fitted to a breathing circuit as a male connector, whereas the larger diameter adult size connector acts as a female connector when fitting to the breathing circuit. Key dimensions are driven by the ISO 5356.1.2004 standard for Anaesthetic & Respiratory Equipment - Conical Connectors.

The multifunctional airway device according to the invention is suitable for use in, but not limited to, the following, difficult airway situations, e.g. difficult bag mask ventilation situations; resuscitation; pre-oxygenation of mask-phobic patients; awake fibreoptic intubation; combined bite block and oral airway for the passage of devices such as endoscopes therein through.

A standard definition of "difficult airway situations" cannot be identified in the available literature but can be defined as the clinical situation in which a conventionally trained anesthesiologist experiences difficulty with facemask ventilation of the upper airway, difficulty with tracheal intubation, or both. The difficult airway represents a complex interaction between patient factors, the clinical setting, and the skills of the practitioner.

A difficult airway can include, but is not limited to the following: 1.) Difficult facemask ventilation. It is not possible for the anesthetist to provide adequate ventilation because of one or more of the following problems: inadequate mask seal, excessive gas leak, or excessive resistance to the ingress or egress of gas. Signs of inadequate ventilation include (but are not limited to) absent or inadequate chest movement, absent or inadequate breath sounds, auscultatory signs of severe obstruction, cyanosis, gastric air entry or dilatation, decreasing or inadequate oxygen saturation (SpO2), absent or inadequate exhaled carbon dioxide, absent or inadequate spirometric measures of exhaled gas flow, and hemodynamic changes associated with hypoxaemia or hypercarbia (e.g., hypertension, tachycardia, arrhythmia). 2. ) Difficult laryngoscopy: It is not possible to visualize any portion of the vocal cords after multiple attempts at conventional laryngoscopy. 3. ) Difficult tracheal intubation: Tracheal intubation requires multiple attempts, in the presence or absence of laryngeal or tracheal pathology; and, 4. ) Failed intubation: Placement of the endotracheal tube fails after multiple attempts.

A traditional respiratory mask includes a fixed domed or cup-shaped device that fits over the mouth and nose of a wearer. The edge of this dome or cup fits against the face of the wearer. The multifunctional airway device according to the invention avoids the need for pressure contact between a patient’s facial skin and the mask. This is beneficial in some cases as pressure could cause injury to the patient, e.g. after facial trauma, burns, skin infection or the like.

When the multifunctional airway device is used with an anaesthetic or breathing circuit for procedural sedation, the patient’s breathing can be continuously monitored by observing the rhythmical emptying and filling of the reservoir bag and also end tidal carbon dioxide can be continuously monitored during the procedure.

Currently, using prior art devices, an anaesthetist has to achieve a seal between a face mask and the patient’s face at induction of anaesthesia. If the anaesthetist cannot achieve a seal, the patient may become hypoxic. However, with the multifunctional airway device according to the invention a seal is achieved inside of the mouth with the lips/cheeks and by pinching or clipping the nose.

Direct connection of the multifunctional airway device to a breathing or anaesthetic circuit is facilitated by the connector. For example, the multifunctional airway device according to the invention can be directly connected to an anaesthetic or breathing circuit. In the event that difficult bag mask valve ventilation is anticipated, the oral multifunctional airway device with it’s self-retaining and self-sealing flange can be positioned before general anaesthetic induction or the multifunctional airway device and flange can be positioned after general anaesthetic induction. -13Due to the presence of the central channel in the airway body, the multfunctional airway device can serve as a conduit through which to administer oxygen and inhalational anesthetic agents, e.g. sevoflurane, isoflurane, desflurane, nitrous oxide and the like.

The oropharyngeal multifunctional airway device can be positioned in an awake patient who has had his airway anaesthetised with local anaesthetic. When the multifunctional airway device is used, a breathing or anaesthetic circuit with a proprietary catheter mount adaptor incorporating a self-sealing aperture can be connected to the multifunctional airway device. This facilitates oral fibreoptic intubation while maintaining oxygenation. FOI can be achieved using a proprietary airway exchange catheter (e.g. Aintree airway exchange catheter, Cook Medical airway exchange catheter).

When the oral multifunctional airway device, with an angle piece incorporating a selfsealing aperture, is used with a breathing or anaesthetic circuit for upper gastrointestinal endoscopy, bronchoscopy or transoesophageal echocardiography, it will facilitate the maintenance of oxygenation.

When the multifunctional airway device, connected to an anaesthetic or breathing circuit delivering 100% oxygen, is used as a combined bite-block and oral airway for endoscopic procedures airway difficulties are less likely to occur. If they do occur, they will be more quickly recognized and can be more effectively treated than by using currently used biteblocks.

Currently, the most commonly used prior art devices for endoscopy are bite-blocks placed between the upper and lower teeth and supplemented with oxygen delivered via nasal cannulae. Bite-blocks have to be either strapped in place or continuously held in place for the duration of the procedure. The detection of airway difficulties may be delayed and the treatment of airway difficulties maybe difficult for Endoscopists leading to dangerous hypoxia. Other prior art devices, such as ventilating endoscopy masks, are available but are not widely used due to various functional limitations with their use. They need to be strapped in place, it is hard to achieve a seal with the face and are claustrophobic.

BMV ventilation can be difficult to achieve in the collapsed non-breathing patient even for experienced health care professionals, because one has to simultaneously maintain a patent airway while at the same time achieve a seal between the face mask and the - 14patient’s face. The multifunctional airway device according to the invention offers an alternative bag valve airway ventilation or mouth valve airway ventilation which many resuscitators will find easier to achieve adequate ventilation. It is much easier to achieve a seal with the multifunctional airway device according to the invention than with a bag mask valve. This is due to the self retaining and self sealing flange which, in use, is placed between the lips and cheeks and gums or teeth of a patient. Simultaneously, the multifunctional airway device aids in the maintenance of a patent airway. During cardiopulmonary resuscitation (CPR), and especially sole provider delivered CPR, delays are minimized between cycles of chest compressions and rescue breaths because the multifunctional airway device is retained in position as the rescuer alternates between cycles of chest compressions and rescue breaths.

Due to the fact that the multifunctional oral airway device according to the invention can be placed when the patient is awake, and that the multifunctional oropharyngeal airway device according to the invention can be placed when the patient is lightly anaesthetised (similar to a Guedel airway), an unhurried gentle induction of anaesthesia can be achieved even in those patients where a seal cannot be achieved between mask and face, e.g. patients with facial hair, edentulous, skin condition, facial deformity and obese patients. Simultaneously, the multifunctional airway device helps in keeping the patient's airway patent.

The multifunctional airway device according to the invention helps to maintain oxygenation and anaesthesia and can aid FOI. This will be of particular value to the anaesthetist when faced with the unexpected "Difficult Intubation" after induction of anaesthesia. If unexpected difficult intubation occurs, oxygenation can be maintained because of preoxygenation and apneic oxygenation and also ventilation and FOI achieved with the multifunctional airway device. However, ancillary equipment such as an airway exchange catheter will be required.

FOI is a core skill for anaesthetists and is often considered the best option for the patient with a difficult airway. Many anaesthetists lack confidence in their ability to perform FOI. Using the multifunctional airway device for FOI makes the procedure less time critical because oxygenation can be maintained for longer. The breathing or anaesthetic circuit remains connected to the patient during FOI under anaesthesia thus maintaining oxygenation and anaesthesia. During awake FOI, the multifunctional airway device can - 15deliver 100% oxygen. Unlike conventional FOI airways (Berman, Ovassapian) when the multifunctional airway device is used, a closed anaesthetic circuit can be used allowing for 100% oxygen and positive pressure breaths to be administered to the patient.

The multifunctional airway device according to the invention is for use in procedural sedation such as required for endoscopy, bronchoscopy, transoesophageal echocardiography. The invention provides a method of using the oral airway device with an angle piece connector fitted with a self-sealing aperture described herein to facilitate endoscopic procedures such as bronchoscopy, gastroscopy and transoesophageal echocardiography, said method comprising the following steps: (i) Fit the detachable intraoral flange onto the airway body to the desired length and up to a maximum of slotting it into the groove on the airway connector; (ii) Place the distal end of the oral airway body into the patient's mouth and connect the breathing circuit; (iii) Pass the endoscope through the angle piece connector with a self-sealing aperture through the oral airway device into the patient's larynx or oesophagus as appropriate; (iv) During the procedure, monitor the rhythmical filling and collapse of the reservoir bag of the breathing circuit.

The multifunctional airway device can be used by all airway management personnel, for example, experienced anaesthetists, trainee/junior anaesthetists, Accident and Emergency (A&E, casualty) medical staff, nurses, paramedics and first responders.

From a further aspect, the invention provides a method of using the oral airway device described herein to facilitate preoxygenation prior to anaesthetisation of a mask phobic patient, said method comprising the following steps: (I) Place the distal end of the oral airway device in the mouth of the patient until the intraoral flange reaches the gums and close the patient’s mouth over the intraoral flange; (ii) Connect the proximal end of the oral airway device to a breathing or anaesthetic circuit delivering 100% oxygen via the connector on the airway body; and (iii) Either clip or pinch the patient’s nose or request the patient to pinch his own nostrils closed and to breathe through his mouth.

This method is especially useful for claustrophobic patients who refuse to breathe from a face mask. Anaesthetists routinely preoxygenate patients, especially in emergency cases before anaesthesia.

The invention further provides a method of using the oral or oropharyngeal airway device described herein to facilitate positive pressure breathing during resuscitation of an unconscious patient, said method comprising the following steps: (i) Fit the detachable intraoral flange onto the groove in the connector on the airway body; (ii) Place the distal end of the oral or oropharyngeal airway body into the patient’s mouth or oropharynx; (iii) Connect the proximal end of the oral or oropharyngeal airway device to a breathing or anaesthetic circuit via the connector on the airway body or alternatively to the one way fluid filter for mouth to airway positive pressure breaths; and (iv) Clip or pinch the patient's nose to close the patient’s nostrils.

From yet a further aspect, the invention provides a method of using the oral or oropharyngeal airway device described herein for fibreoptic intubation of an anaesthetised patient: (i) Fit the detachable intraoral flange into the groove on the connector on the airway body; (ii) Place the oral or oropharyngeal airway device into the patient’s mouth or oropharynx; (iii) Connect an anaesthetic circuit to the connector of the ora! or oropharyngeal airway device; (iv) Pinch or clip the patient’s nostrils; (v) Mount a proprietary airway exchange catheter (e.g. an Aintree or Cook medical proprietary airway exchange catheter) onto the fibreoptic bronchoscope; (vi) Pass the bronchoscope through the self-sealing aperture of the oral or oropharyngeal airway device into the patient’s larynx and trachea; (vii) Advance the airway exchange catheter over the bronchoscope into the trachea; (viii) Remove the bronchoscope; (ix) Temporarily disconnect the anaesthetic circuit from the oral or oropharyngeal airway device and railroad an endotracheal tube over the airway exchange catheter into the trachea; (x) Remove the airway exchange catheter and connect the anaesthetic circuit to the endotracheal tube.

The oral or oropharyngeal airway device described herein may also be used for fibreoptic intubation of an awake patient.

The invention will now be described more particularly with reference to the accompanying drawings which show, by way of example only embodiments of the multifunctional airway device according to the invention. In the drawings: Figure 1A is a perspective view from the one side of a first embodiment of an assembled oral airway device according to the invention consisting of a flexible flange and a rigid oral airway body; Figure 1B is a perspective view from the other side of the assembled oral airway device of Figure 1A; Figure 2A is a perspective view from one side of the flexible flange of the first embodiment; Figure 2B is a perspective view from the other side of the flexible flange; Figure 2C is a side view of the flexible flange; Figure 2D is a plan view of the flexible flange; Figure 2E is a cross-section view of the flexible flange along the lines Έ-Ε" of Figure 2C; -18Figure 2F is an end view of the flexible flange; Figure 2G is a cross-section view along G-G in Figure 2C; Figure 3A is a side view of the rigid oral airway body of the first embodiment; Figure 3B is a plan view from above of the rigid airway body; Figure 3C is a perspective view of the rigid airway body; Figures 4A, 4B and 4C are three plan views showing fitting of the flexible flange over the rigid airway body in three locations; Figure 5A is a plan view of the first embodiment of the assembled airway device with an angle piece connector fitted with a self sealing aperture provided at the proximal end of the oral airway device; Figure 5B is a side view of the device shown in Figure 5A; Figure 5C is a perspective view of the device as seen from the proximal end and Figure 5D is a perspective view of the device from its distal end; Figures 6A, 6B and 6C are respectively side, plan and perspective views of the angle 25 piece connector fitted with a self sealing aperture at the proximal end; Figures 7A and 7B are respectively a plan view and a side view of the assembled airway device and illustrating in dotted view how the flange can be used in practice, with the concave face of the flange facing towards the patient; Figures 8A, 8B, 8C and 8D are respectively, a first plan view, a second plan view, a first side view and a second side view of how the flange can be used in practice with the concave face of the flange facing towards the patient; - 19Figures 9A, 9B and 9C are respectively, a partially exploded perspective view of the complete airway device with an angle piece connector fitted with a seif sealing aperture, a perspective view of the assembled complete airway device and a perspective illustration of how the device is manipulated by a user; Figures 10A, 10B, 10C and 10D are respectively a plurality exploded perspective view of the airway device without the angle piece connector, a perspective view of the assembled device with the concave face of the flange facing towards the proximal end of the oral airway tube; a perspective view of the assembled device with the flange shown in dotted view being flipped towards the distal end of the oral airway and a perspective view of the flange in dotted view; Figures 11A and 11B are respectively, a side view and a plan view of the second embodiment of the airway device including an elongate curved oropharyngeal airway tube and an angle piece connector fitted with a self sealing aperture at the proximal end.

Figure 11C is a perspective view of the elongate curved airway tube; Figures 12A and 12B are respectively, a side view and a plan view of the assembled airway device of the second embodiment including the flange fitted over the airway and with the concave face facing towards the distal end of the airway tube.

Figures 13A and 13B are cross-sectional side views of the assembled airway device of the first embodiment with a one way valve fitted in the proximal end of the oral airway body and Figure 13C is a cross-sectional side view of the assembled airway device of the second embodiment with a one way valve fitted in the proximal end of the oropharyngeal airway body.

Figure 14A is a side view illustrating how the assembled airway device, including the angle piece connector with a self sealing aperture is inserted into the mouth of a patient and Figure 14B is a side view illustrating how the device is located in position in the patient's mouth.

Figure 15 is an end view of the airway fitted in the patient’s mouth with the outline of the flange shown in dotted view; and -20 Figure 16 is a perspective view from the proximai end of the assembled airway device of the first embodiment including the angle piece connector with a self sealing aperture with an endoscope passing there through.

Referring to the Figures, like reference numerals refer to like features. In Figures 1 to 4C a multifunctional airway device according to one embodiment of the present invention is shown, generally indicated by the reference numeral 100. Multifunctional airway device 100 is an oral airway device suitable for an adult and comprises an elongate, tubular oral airway body 101. Airway body 101 has a substantially straight section 102, the proximal end of which is adapted to function as an integral bite block and has a connector 103, a narrowed distal section 104 with a distal tip 105 and a central channel 106 for accepting an intubation device (not shown). Distal tip 105 and the narrowed distal section 104 facilitate placement of the airway device 100 into a patient’s mouth.

Oral airway device 100 also has a substantially oval, concave/convex shaped detachable intraoral flange 130 having a central aperture 131 for receiving the airway body 101 and two wings 133. Central aperture 131 is substantially circular and located centrally with respect to each of the minor and major axes of the intraoral flange 130 and provides a passage through the flange 130. Reinforcing rim 132 is provided about the perimeter of the flange and reinforcing rim 134 is provided about the central aperture 131. The detachable intraoral flange 130 is made of flexible material and is adapted to fit between a patient's gums and lips to seal the patient’s mouth opening. Midline indentations 135 and 136 in the top and bottom of flange 130 prevents the flange from irritating frenula between the lips and gums of the patient. The airway body 101 has a groove 121 for accepting the flange 130 and a second groove 122 for accepting tie material for attaching the airway device to a patient. The airway body 101 is adapted to pass through central aperture 131 of the flange 130 until the flange is located in groove 121.

The underside of the substantially straight section 102 of airway body 101 is provided with a glottal surface which has a horizontal profile when in use it is in relative position with the tongue and has a shape substantially following the contours of the mouth to increase its area of contact with the tongue. Distal tip 105 has a curved underside which aids placement of oral airway device 100 into the patient’s mouth by spreading pressure - 21 across the tongue. Multifunctional oral airway device 100 can thus be placed into the patient without turning it upside down first.

Detachable intraoral flange 130 is placed with or independently of airway device 100 either before or after induction of anaesthesia or sedation. For example, flange 130 is placed in the mouth before induction of anaesthesia and airway device 100 is passed through aperture 131 of flange 130 after the induction of anaesthesia. Alternatively, airway device 100 together with the intraoral flange attached is positioned before induction of anaesthesia.

The multifunctional oral airway device is used according to the following method: Before the induction of general anesthesia, the distal end of the multifunctional ora! airway device is placed in the mouth of the patient and connected to an anaesthetic circuit via connector 103. After the induction of general anaesthesia the patient’s nose is then clipped or pinched to close the nostrils for positive pressure breathing. When used for procedural sedation the multifunctional oral airway device is connected to a breathing circuit.

With reference to Figures 5A to 9C, an angle piece connector 140 is integrally formed with the connector 103. The connector 140 is provided with a self-sealing aperture 145.

Referring now to Figures 11A to 12B, a multifunctional oropharyngeal airway device according to a second embodiment of the present invention is shown, generally indicated by the reference numeral 200. Multifunctional airway device 200 is suitable for an adult and comprises an elongate, tubular airway body 201. Airway body 201 has a substantially straight section 202, the proximal end of which is adapted to function as an integral bite block, a curved distal section 204 with a distal tip 205 and a central channel 206 for accepting an intubation device (not shown). Distal tip 205 and curved distal section 204 facilitate placement of the airway device 200 into a patient’s mouth and throat.

Oropharyngeal airway device 200 also has the substantially oval, concave/convex shaped detachable intraoral flange 130 and a connector 203. Airway body 201 is adapted to pass through central aperture 131 of the detachable intraoral flange 130 until the flange is located in groove 221. -22The underside of the substantially straight section 202 of airway body 201 is provided with a glottal surface which has a horizontal profile when in use it is in relative position with the tongue and which sweeps down substantially following the contours of the mouth to increase its area of contact with the tongue. This assists in preventing the tongue from obstructing the pharynx. Distal tip 205 has a curved underside which aids placement of oropharyngeal airway device 200 into the patient’s mouth and throat by spreading pressure across the back of the tongue. Distal tip 205 is provided with a downwardly offset rim 215 which aids placement of oropharyngeal airway device 200 into the patient’s mouth and throat by spreading pressure across the back of the tongue. Multifunctional oropharyngeal airway device 200 can thus be placed into the patient without turning it upside down first.

Detachable intraoral flange 130 is placed with or independently of airway device 200 after induction of anaesthesia. For example, flange 130 is placed in the mouth before induction of anaesthesia and airway device 200 is passed through aperture 131 of flange 130 after the induction of anaesthesia. Alternatively, airway device 200 together with intraoral flange 130 attached is positioned after induction of anaesthesia. Distal tip 205 can be advanced or withdrawn into or out of the patient’s pharynx to allow for multifunctional oropharyngeal airway device 200 to be advanced gradually as the level of anaesthesia deepens without activating the patient’s gag reflex.

Figures 13A and 13B respectively show the multifunctional oral device and 13C the oropharyngeal airway device 100 and 200 with a one-way valve 250 in the connector. The one-way valve 250 is similar to those found on rescue masks used for resuscitation.

The use of the airway device 100 will be explained with reference to Figures 2D, 9A to 9C, 10A to 10D, Figures 14A and 14B and Figure 15. To locate the device 100 in the patient’s mouth the anaesthetist uses his fingers to press wings 133 of the intraoral flange 130 in a distal direction towards the distal tip 105. The airway body 101 is then inserted into the mouth passed the lips L and over the tongue TO. When the anaesthetist pushes the flange 130 passed the lips L, he releases the wings 133, they spring back into their normal orientation between the teeth TE of the patient and the lips L, thus creating a gas tight seal. -23There are many advantages offered by this invention. Apart from reducing ora! trauma, the airway device makes the Endoscopist’s task easier and safer for the patient. In particular, the patient cannot stick his tongue into the channel of the airway. Also the airway can be pointed towards the oesophagus or trachea for upper Gl endoscopy or 5 bronchoscopy.

It will of course be understood that the invention is not limited to the specific details as herein described, which are given by way of example only, and that various alterations and modifications are possible without departing from the scope of the invention as 10 defined in the appended claims.

Claims

1. A multifunctional airway device for use as an oral airway device adapted for insertion into the mouth of a patient, said airway device comprising: (a) an elongate, tubular oral airway body of substantially elliptical or substantially circular cross-section, the airway body having: a substantially straight section, the proximal end of which is adapted to function as an integral bite block wherein the distal end of the airway body substantially conforms to the front of the tongue but does not extend into the pharynx; and a central channel for the passage of oxygen and anaesthetic gases and for accepting an endoscope; (b) a connector for facilitating attachment of breathing or anaesthesia equipment thereto, wherein the connector is attached to the proximal end of the airway body and has a groove on its external surface, wherein the groove forms a circular channel for accepting the intraoral flange; and (c) a flange which is flexible, self-retaining and self sealing and having a concave shape and is adapted to be placed with the concave side facing towards the mouth of the patient or concave away from the mouth of the patient and then snapped back into a concave shape facing the mouth of the patient but with the top and bottom of the middle section curved inwards towards the gums and tucked in under the top lip; and having a greater cross-sectional area than the mouth opening with each end being arrow shaped like the corner of the mouth when the mouth is open to aid placement, wherein the airway device acts as a snorkel ventilation airway and bite block.

2. The airway device as claimed in Claim 1 in which the flange has: a) a first reinforced rim around its perimeter thereby providing rigidity while allowing flexibility; b) a central aperture for engagement with the elongate tubular oral airway body and, c) a second reinforced rim around the central aperture, whereby the first and second reinforced rims and the concave shape of the flange resist deformation while having sufficient elasticity to enable the flange to be self retaining and self sealing and also allowing the ends of the flange to be compressible -25between the thumb and forefinger of the user for placement inside the cheeks of a patient.

3. The airway device as claimed in Claim 1 or Claim 2, in which the elasticity of the flange enables it to be placed anywhere along the shaft of the airway and thereby vary the length of the intraoral part of the airway or for maximal intraoral length in a retaining groove on the proximal end of the airway body.

4. The airway device as claimed in any one of the preceding claims, in which when deformed by the cheeks, the central part of the flange maintains some of it’s natural curvature and so is directed inwards towards the gums and teeth which prevents it from protruding from beneath the top lip thereby enhancing the sealing effect of the flange.

5. The airway device as claimed in any one of the preceding claims, in which the device is adapted to provide apnoeaic oxygenation of a patient, whereby if the patient is not breathing, the safe apnoea period is significantly prolonged, by providing an open patient airway, preoxygenation with 100% oxygen and continuing the delivery of 100% oxygen to the pharynx during the apnoeic period.

6. The airway device as claimed in any one of the preceeding claims, the device is adapted so that when used for endoscopic procedures, such as upper gastrointestinal endoscopy, fibreoptic bronchoscopy and transoesophageal echocardiography, it facilitates the endoscopist's task and as a consequence reduces the risk of damaging delicate oral structures, because the patient cannot obstruct the central channel of the airway with his tongue and also because the endoscopist can direct the airway towards the pharynx thus facilitating passage of the endoscope.

7. An alternative embodiment of the airway device describes an oropharyngeal airway device adapted for insertion into the oropharynx of a patient, said airway device as claimed in any one of the preceding claims, wherein the curved distal end of the airway body substantially conforms to the curvature of the part of the patient’s pharynx between the soft palate and the upper edge of the epiglottis.

8. The airway device as claimed in any one of the preceding claims, wherein the detachable intraoral self retaining and self sealing flange is made of flexible material such as plastic, rubber, silicone or other flexible material, preferably polyvinyl chloride.

9. The airway device as claimed in any one of the preceding claims in which the self retaining and self sealing intraoral flange is of a concave/convex shape and a much greater cross-sectional area than the mouth opening, each end is being narrowed to aid placement.

10. The airway device as claimed in any one of the preceding claims in which the detachable, flexible, self-sealing and self retaining flange of a concave/convex shape and a greater cross-sectional area than the mouth opening, with the shape corresponding to the mouth opening when the mouth is open and each end is shaped like the corner of the mouth when open to aid placement.

11. The airway device as claimed in any one of the preceding claims in which the flange is self-retaining as a result of its “shear modulus (modulus of rigidity)” which initially deforms to the curvature of inside the cheeks of the patient but resists further deformity thereby becoming progressively more difficult to deform, due to the gradient of its “stress - strain curve increasing with stress, and therefore does not pop out of the mouth of the patient.

12. The airway device as claimed in any one of the preceding claims in which the flange is self-sealing due to its resilience in that it is quickly and constantly trying to return to its original shape, so that it forms a dynamic seal inside of the mouth of the patient in that it continuously follows variation in the surface of the mouth that it is sealing, thereby continuing to seal during periods of positive pressure ventilation when the mouth may undergo small changes in size and shape during the different phases of the respiratory cycle, whereby the flange maintains a seal as the mouth opening changes size and shape but the sealing effect is enhanced by the gas pressure forcing the seal against the inside of the cheeks.

13. The airway device as claimed in any one of the preceding claims in which the chosen elastomeric material has a high elastic limit but does not display plasticity -27in its working range, so that the lips of the patient function as a purse string largely because of the bulk of the orbicularis oris muscle and the fibromuscular modiolus even when it is relaxed and not contracting, whereby the rim around the perimeter of the flange resists distortion and when in place in the vestibule of the mouth sits outside the orbicularis oris muscle and the fibromuscular modiolus and so retains the flange even during positive pressure breaths and the flange is further supported in position in the vestibule of the mouth between the lips and cheeks, gums and teeth of the patient by the airway device traversing and firmly gripped in the central aperture of the flange.

14. The airway device as claimed in any one of the preceding claims in which the flange has a cut-out in the midline at the top and bottom of the flange to accommodate the top and bottom frenulum.

15. The airway device as claimed in any of the preceding claims in which between the perimeter rim of the flange and the rim surrounding the central aperture, the flange is soft and very flexible, so that during positive pressure ventilation breaths the flange seals the mouth opening by adhering to the soft moist and smooth inner mucosa of the cheeks and lips; the intraoral flange does not seal the large opening between the upper and lower jaws but rather seals the mouth of the patient due to the width of the vestibule of the mouth being much greater than the width of the mouth opening and allowing for the width of the flange to be much greater than the maximum width of the mouth opening, whereby the corners of the mouth are particularly well sealed and no gas leaks from the corners of the mouth.

16. The airway device as claimed in any one of the preceding claims in which the flange contributes to jaw thrust because it resists deformation, whereby the flange is in position in the vestibule of the mouth of the patient it is forced by the cheeks to adopt the contour of the inside of the cheeks, and in resisting deformation because the upper jaw is fixed and not mobile the flange pulls forward the lower jaw.

17. The airway device as claimed in any preceding claim, wherein the airway body is made of a polymer selected from among medical grade polyethylene, polypropylene and polycarbonate, preferably polyethylene.

18. The airway device as claimed in any preceding claim, wherein the groove for accepting the detachable intraoral flange is adapted such that the detachable intraoral flange can be rotated with respect to the airway body.

19. A multifunctional airway device substantially in accordance with any of the embodiments as herein described, with reference to, and as shown in, the accompanying drawings.