Improved airway device

ES 2 395 845 T3

DESCRIPTION

Enhanced airway device

Field of the invention

This invention relates to an improved, simple but versatile anatomically oriented airway device. It is particularly applicable, but by no means limited, to devices used in the administration of anesthesia to a spontaneously breathing patient during a surgical procedure. The present invention relates in particular to a laryngeal airway device. More specifically, the present invention relates to a disposable low cost laryngeal airway device and methods of manufacturing such an airway device.

Background of the invention

Examples of devices currently used in spontaneously breathing anesthetized patients, during recovery after anesthesia, ablactation of a certain group of patients in intensive care, or during resuscitation to provide a clean, hands-free airway are:

a) Guedel breathing tube with various types of face masks.

b) Cuffed oropharyngeal cannula.

c) Laryngeal airway mask (LMA), laryngeal mask for reinforced airway, laryngeal airway mask for intubation and Intavent modified airway laryngeal mask for ear, nose and throat and dental anesthesia.

d) Device for airway treatment.

e) Combined tube.

f) Self-retaining nasopharyngeal tube.

g) Cuffed or uncuffed endotracheal tubes, RAE type endotracheal tubes

h) Supraglottic cannula.

i) Tracheostomy tubes and minitracheostomy tubes.

j) Etcetera.

All of the aforementioned devices carry significant and variable degrees of morbidity involving not only unacceptable concurrent physiological changes but also temporary or permanent anatomical and structural damage. Many cases of mortality caused directly or indirectly as a result of the use of devices of this type have been reported.

Probably the most successful design variant is the inflatable airway laryngeal device, variants of which have been used to deliver anesthesia gases since 1988.

A brief history of the development of such an airway device is described in a review by AIJ Brain in the "European Journal of Anesthesiology 1991", Supplement 4, pages 5 to 17 inclusive.

If the respiratory tree is viewed as a tube ending in the glottis and the goal is to make a simple connection between this tube and an artificial tube to supply gas under pressure to the bronchial tree, it may seem logical to form a direct end-to-end junction between the tubes. two tubes. The face mask of course forms an end-to-end junction, but with the wrong hole, while the endotracheal tube finds the correct hole but goes too far into the lumen, so the junction is made inside the lumen. , rather than on its edge. The undesirable aspects of intubation of the trachea result from the fact that, to effect a joint, pressure is applied to an epithelial surface whose important and highly specialized functions are therefore compromised and because through the penetration of the vocal cords, makes it impossible to cough effectively, the architecture of the upper airway is distorted and an unwanted reflex response is elicited not only by the necessary laryngoscopy prior to intubation but also by the presence of the endotracheal tube in the trachea. Laryngeal masks of this type have been used in anesthesia practice since 1988 and many reports of morbidity or mortality directly or indirectly related to their use have been reported. Complications or morbidity are caused by hyperinflation and the impact of extra-luminal pressure on soft tissue and cartilaginous structures in contact with the

ES 2 395 845 T3 hyper inflated cuff.

Various attempts have been made to improve this type of airway device but they still suffer from a number of inherent serious drawbacks. First, they require cuff inflation to be effective, and furthermore, anesthesia gas (nitrous oxide) can diffuse into the cuff, expanding the air in the cuff, thereby increasing the extra-luminal pressure of the cuff significantly. and, as a result, putting considerable pressure on the sensitive tissues of the laryngopharynx. Second, these masks have a tendency to shift from one side to the other or rotate about their longitudinal axis when a force is applied to the proximal end of the tube, attached to the anesthetic equipment. It will be appreciated that if such a device is to rest perfectly symmetrically in use then the airway tube will be aligned with the nose of the patient. However, any twisting or lateral movement of the airway tube will have the potential to affect the seal that the airway device makes around the inlet of the larynx.

Various types of airway devices have been described in the patent literature. For example, US 5,976,072 (Johns Hopkins University) describes a fiberoptic endotracheal intubation device. However, this is based on an inflatable pharyngeal oropharyngeal cuff which suffers from the disadvantages referred to earlier herein.

WO 02/32490 (Miller) describes a further type of airway device comprising a non-inflatable preformed saccule chamber and a semi-rigid hollow stem.

US 5,865,176 (O'Nell) and GB 2,319,182 (VBM Medizintechnik GmbH) describe airway devices provided with a double inflatable cuff arrangement, a first inflatable cuff to provide a gasket in the patient's pharynx, and a second cuff. Inflatable to provide a gasket in the patient's esophagus. This arrangement compounds the problem of tissue damage as stated earlier in this document.

In an opposite arrangement, GB 2,373,188 (Smiths Group plc) describes an inflatable laryngeal mask with a teardrop-shaped blocking plate to prevent the mask from blocking the epiglottis during insertion. All of this only contributes to emphasizing the potential disadvantages of such a tubular inflatable mask.

Finally, WO 00/61213 (Brain) describes a disposable laryngeal mask airway device with an inflatable cuff. However, it not only suffers from all the disadvantages of an inflatable cuff device, but is also formed from multiple components, adding to the cost and complexity of manufacture.

Collectively, these documents represent the closest prior art known to the applicant.

It is an object of the present invention to overcome or mitigate some or all of these problems.

Summary of the invention

A first aspect of the present invention provides an airway device as described in the appended claims.

Accordingly, according to a first embodiment, there is provided an airway device for human or animal use, comprising an airway tube provided with a distal end and a proximal end, wherein the distal end of which is surrounded by a laryngeal cuff adapted to form an anatomical fit over the laryngeal inlet of a patient, characterized in that the device further comprises an oral cavity stabilizer positioned on or around the tube for the airway between the laryngeal cuff and the proximal end of the tube, said oral cavity stabilizer being adapted to rest on the anterior face of the tongue patient size, shape, the smoothness and configuration of the oral stabilizer being adapted to provide stability and to prevent twisting or side-to-side movement of the airway tube in use;

wherein the cuff is non-inflatable it is preformed to a shape adapted to form an anatomical fit over the patient's laryngeal inlet;

characterized in that the laryngeal cuff is formed from a plastic material with a Shore hardness on the A scale of 40 or less.

This buccal cavity stabilizer can be formed from the same material as the cuff or from a different material and aids in positioning and maintaining the position of the device in use.

Airway devices according to the present invention will be referred to in the text that follows.

ES 2 395 845 T3 by the abbreviation NLA (Nasir Laryngeal Airway Device), named after the inventor.

The cuff is non-inflatable and is preformed to a shape adapted to form an anatomical fit over the laryngeal body of a patient. The aryepiglottic fold, the arytenoid and corniculate cartilages, the interarytenoid fold, and the piriformis fossa make the laryngeal structure anatomically irregular. The terms laryngeal inlet, laryngeal body, and laryngeal structure are used interchangeably in the following description. These terms refer to the area of ​​a patient's larynx and the surrounding tissues, folds, and cartilage as illustrated in Figure 1.

The device is a mirror image of the laryngopharyngeal body thereby providing an anatomical fit to the irregular structural body of the laryngopharynx. The incorporation of an anatomically designed cup or cuff also offers advantages over the use of an inflatable cuff which exerts significant additional luminal pressure not only well beyond the pressure (22-26 mm / Hg) which is being delivered to the soft tissue surface but also distorts, compresses, dislocates, dislodges or fractures the structures in contact with the cuff. Extra luminal pressure is exerted on the laryngopharyngeal structure not only by repeated inflation of the cuff with air to create an adequate seal, which is achieved at the cost of distortion of the surrounding structures by undue pressure caused by a cuff. taut with a rounded smooth face, it is also increased in situ by the absorption of nitrous oxide (anesthetic gas) within the lumens of the cuff. This can increase the pressure of the cuff beyond 100 mm Hg immediately, rising beyond 200 mm Hg in one hour of use, which is well above normal intracellular pressure or the pressure at which the capillaries of blood supply to the laryngeal-pharyngeal structures.

Preferably the face of the laryngeal cuff adapted to form an anatomical fit over the laryngeal body of a patient incorporates protrusions designed to form a good seal with the piriformis fossa and aryepiglottic folds of the laryngeal body of the patient. It is also preferred that the face of the laryngeal cuff incorporates protrusions designed to form a good seal with the epiglottic vallecula, epiglottis, aryepiglottic folds, piriformis fossa, and around the anterior aspect of the thyroid and cricoid cartilages. The seal around these features can also be reinforced or enhanced by one or more feather-shaped ridges placed around part or all of the perimeter of the laryngeal cuff. This design enables an increased joint pressure that will allow an excess of 30 cm H2O to be obtained.

Additionally, the face of the laryngeal cuff adapted for a tight fit over the laryngeal inlet of a patient may incorporate grooves designed to allow passage of vital arteries, veins and nerves supplying the laryngeal structure.

The distal tip of the laryngeal cup can be dimensioned and shaped such that it remains above the upper esophageal sphincter in use. Most preferably the distal tip of the laryngeal cup is substantially concave in shape.

As an alternative, which does not belong to the invention, the part of the laryngeal cup can be pre-formed from a material which is adapted to absorb a liquid such as water, mucus, blood or similar matters to swell to conform to the body. anatomical muco-cartilage of the laryngeal inlet, for example, a material such as CRM (a blend of rayon and cotton), used to make TAMPAX (tampons) or Compressed Gel Foam5 (compressed gel foam).

Preferably the oral cavity stabilizer first has a ventral face in substantially the same plane as the plane of the open face of the laryngeal cuff and the first face of the oral cavity stabilizer is substantially concave in shape. This assists the operator in inserting the device into the patient and in bringing the oral cavity stabilizer into contact with the patient's tongue.

Preferably the oral cavity stabilizer extends from the proximal end of the laryngeal cuff toward the proximal end of the airway tube such that the cuff and oral cavity stabilizer are of an integral construction. This provides a sleek, elegant device with an attractive and practical design.

Preferably the oral cavity stabilizer is not uniform in its width W, having a wide point positioned at an intermediate point of the laryngeal cuff and the proximal end of the airway tube and more preferably the wide point of the oral cavity stabilizer is closer to the laryngeal cuff than to the proximal end of the airway tube. This arrangement places the widest or widest area of ​​the stabilizer in contact with the base of the patient's tongue when in use.

Preferably the ratio of the width W of the oral cavity stabilizer at its widest point to the height H of the oral cavity stabilizer at the same point is 2.7 ± 10%.

Advantageously, the face of the buccal cavity stabilizer which comes into contact with the patient's tongue can be roughened to increase the friction of the stabilizer with the tongue in use.

ES 2 395 845 T3

In an alternative embodiment, which does not belong to the invention, the oral cavity stabilizer can be adjusted in size, for example when the oral cavity stabilizer is formed from a unit, at least part of the which is slidably mounted relative to the airway tube.

In a particularly preferred embodiment the oral cavity stabilizer is formed as an integral part of the airway tube and further preferably the oral cavity stabilizer, the airway tube and the laryngeal cuff are all formed as one integral set.

The Shore hardness of the various parts, parts or components is an important characteristic of the invention. For example the laryngeal cuff is preferably formed from a material with a Shore hardness on the A scale of 40 or less and more preferably between 0 and 20 and more preferably between 4 and 12.

Preferably the laryngeal cuff and a front, ventral part of the oral cavity stabilizer are formed from a material of substantially the same Shore hardness. This simplifies construction and ensures that all parts of the device that come into firm contact with the soft tissues of the patient are relatively soft.

In a further preferred embodiment a back or back piece of the device and a front or ventral piece of the device are formed from materials of different Shore hardnesses. This enables the dorsal part to be made of a firmer material than the ventral part.

Preferably the back or back piece of the device is formed from a material of Shore hardness less than 60 on the A scale, more preferably between 25 and 45 and most preferably between 30 and 40.

As an alternative that does not belong to the invention, the laryngeal cuff can be inflatable. While this is not ideal, it still represents a significant improvement over and over inflatable masks of the prior art.

Preferably the device further incorporates a passage for a gastric tube extending from the lip of the cuff to the proximal end of the device.

According to the second and third aspects of the present invention there are provided methods of manufacturing an airway device as set forth in claim 7 and claim 9.

Brief description of the drawings

The invention will now be described by way of example only, with reference to the accompanying drawings in which:

Figures 1A to C illustrate various views of laryngeal cartilage and ligaments. This illustration is derived from Tortora GJ, Grabowski G, Reynolds S. Principles of Anatomy and Physiology John Wiley, 10th edition, 2003, Page 781;

Figures 2 and 3 illustrate a plan view of two embodiments of the present invention;

Figures 4-7 illustrate two further embodiments with exploded views each showing an airway device in two halves with an airway tube sandwiched between the halves;

Figure 8 shows an optional feature of a second passage or tunnel beginning at the proximal end side face of the NLA and curving toward the distal end to provide its distal NLA tube hole with a rear face of the NLA tube through the mask to allow the passage of an orogastric tube;

Figure 9 shows a longitudinal slit running substantially the length of the mask to accommodate an endotracheal tube used in anticipated or unexpectedly difficult tubing, with or without the use of a spark plug, Cook's airway, or fiber optic indicator;

Figures 10.1 to 10.6 show various plan, side and cross-sectional views of a further embodiment of the present invention;

Figures 11, 12 and 13 show two front views and one side or side views of a further example in which the buccal cavity stabilizer is adjustable in size;

Figure 14 schematically shows an airway device according to the present invention fitted over a laryngeal inlet; Figure 15 (canceled);

Figure 16 illustrates a series of schematic perspective, cross-sectional and exploded views of a

ES 2 395 845 T3 airway device, showing that the airway tube itself may be positioned protruding from the main body of the device;

Figures 17A-F show front, rear, side and end elevational views of a further preferred embodiment of the present invention;

Figures 18A, B and C show front and side elevations of particularly preferred embodiments incorporating thin, flexible ridges around a portion of the circumference of the laryngeal cuff;

Figures 19, 20 and 21 show various schematic cross-sectional and isometric views of devices according to the present invention placed in situ in a human patient;

Figure 22 illustrates a section along the line YY shown in Figure 21.

Description of preferred embodiments

Embodiments of the present invention are described hereinafter by way of example only. These examples represent the best modes of carrying out the invention that are currently known to the applicant although they are not the only ways in which this can be achieved.

With reference to Figure 2, this illustrates the distal end of a mask device according to a first embodiment of the present invention, globally represented as 10. It comprises an airway tube 11, which at its proximal end 12 (not shown) terminates in a 15mm connector or other suitable connector for connection to a conventional anesthetic breathing system. Formed around the distal end 13 of the airway tube is a laryngeal cuff or cup 14 adapted in shape and contoured to correspond to the entry zone of a patient's larynx. In this context the terms sleeve and cup have an equivalent meaning. They refer to the element of the device at the distal end of the airway tube that is adapted to cover and form a seal with the laryngeal inlet of the patient. In the context of this description, the term "proximal" means the end of the device, or part thereof, closest to the connection to the anesthetic breathing system. The term "distant" means the end of the device, or part of it, that is furthest from the anesthetic breathing system.

Laryngeal cuffs, in general, are well known to specialists and the anatomy of the laryngeal entrance area of ​​a human being is represented in some detail in Figures 1A, B and C. The particular cuff represented in Figure 2 incorporates on the face of the sleeve bulges or protrusions 15, 16 designed to form a good joint with the piriformis fossa and the aryepiglottic folds. It will be appreciated that the outward protrusions on the sleeve at 15 and 16 are positioned antero-laterally to provide an anatomical seal by fitting within the piriformis fossa and aryepiglottic folds. Therefore, in side elevation, the face of the sleeve is not a flat, smooth surface but includes areas that protrude above the general plane of the face of the sleeve. Additionally, they may optionally be zones which lie below the general plane of the face of the sleeve. These conformations and the overall size, shape, and surface configuration of the sleeve face around the hole 17 are an important feature of the invention. Alternative shapes for the sleeve face are depicted in Figures 3, 5, 10, 11, 12, 17 and 18 and are described in more detail later in this document.

The device can be constructed from any suitable plastic material as selected by materials specialists. Latex-free medical grade silicone rubber is a preferred material. The cuff should be soft in texture to avoid undue damage to surrounding tissues. Other suitable materials for the construction of this type of device include, but are not limited to, polyvinyl chloride (PVC), thermoplastic elastomers such as styrenic block copolymers, (for example, styrene butadiene styrene (SBS), styrene ethylene butylene styrene (SEBS)) and blends of olefin thermoplastics (TPO), thermoplastic polyurethane elastomers (TPU), copolyester (COPE), polyether block amides (PEBAX) and foamed versions thereof, where appropriate.

An additional important factor involved in choosing a suitable material is transparency. Ideally the building material (s) should be substantially clear or transparent. This allows the anesthetist or operator to view the inner lumen of the airway to check for blockages or other problems. Such transparent materials are known to those skilled in the art.

According to the invention, the cuff is non-inflatable and is formed from any suitable soft plastic material with a Shore hardness in the A scale of 40 or less. As a preferred range of softness (hardness), on the Shore hardness scale A, a hardness of less than 40 is optimal for the face of the sleeve that is in contact with the laryngeal inlet. As a preferred range, a value on the same scale of between 0 and 20 is preferred, with a particularly preferred range of 4 to 12. The softness of the sleeve can be further adapted by forming cavities or channels within the body of the sleeve itself (shown in Figures 4 and 5).

In a further example, which does not belong to the invention, the sleeve may be previously filled with such a fluid

ES 2 395 845 T3 such as air, or another non-toxic gas, or a non-toxic liquid. In this context the term fluid has a broad meaning and includes any gas, liquid, vapor or combination thereof and will be determined and designed by an expert in this field of anatomy and anesthesia in conjunction with specialists in materials. The cuff will be constructed of a material such that it does not allow nitrous oxide (anesthetic gas) to diffuse through the material in a significant amount so that the extra luminal pressure remains constant. It follows, therefore, that the sleeve must be substantially impermeable to the fluid with which it is filled and to anesthetic gases.

Alternatively, the sleeve may be formed from a soft foamed material or it may be foam filled. In either case this provides a soft, deformable but shaped surface around the face of the cuff to fit over the anatomy of the laryngeal entrance area. Such a foam filled device will minimize any potential damage to structures in that area while still providing a substantially complete joint.

Directly adjacent to the cuff or laryngeal cup but positioned proximal to the airway tube towards the cuff itself is an oral cavity stabilizer 20. In this example this stabilizer takes the form of an expanded zone extending symmetrically to each side of the airway tube. This stabilizer is adapted to rest on the anterior or front face of the tongue and is configured to correspond to the anatomy of that part of the patient.

A wide variety of shapes, sizes, and placements are possible for this stabilizer. The one illustrated in Figure 2 is curved in the plane of the sleeve face such that the visible face in Figure 2 is slightly concave, with the rear face being slightly convex. The face of the stabilizer may be rough, scored or serrated to increase friction with the tongue and thereby stabilize it in use, to prevent or reduce forward or backward movement when in use.

In this example the stabilizer is integrally formed with the sleeve, so that one runs smoothly into the other. However, this is not essential and the stabilizer can be a separate assembly on the airway tube. An essential feature of the stabilizer is that it is wider in cross section than the diameter of the airway tube itself. That is, it extends into an area on each side of the airway tube and generally in the same plane as the laryngeal cuff. Preferred dimensions for the oral cavity stabilizer will be discussed later in this document.

A further example of a different design of the buccal cavity stabilizer is illustrated in Figures 11, 12 and 13. In this example the stabilizer 50 is adjustable and has two side hooks 51, 52 on the side faces, near the proximal end of the airway tube, which can slide down and up to increase or decrease the size of the ridges for adequate stability and for ease of insertion and removal of the NLA. The hooks engage in ratchet strips 53, 54, formed on opposite sides of the airway tube. The stabilizer is formed from a flexible, elastically deformable material such that the hooks are forced from their position as depicted in Figure 11 to a position closer to the sleeve at the distal end of the tube, as illustrated in Figure 12, the extension of the stabilizer on each side of the airway tube increases the further the hooks are moved towards the cuff and therefore the wider the stabilizer. Thus the stabilizer extends from the proximal end of the airway tube, just below the connector to the proximal end of the laryngeal cuff. The stabilizer is substantially symmetrical in shape and can slide downward to provide an extended shape through the oral cavity. Figure 13 shows an oblique side view of this embodiment.

This is just one of the many procedures which can be used to form a stabilizer. A stabilizer can be formed from any extension, preferably soft, around the airway tube that can rest on the anterior aspect of the tongue. Any suitably shaped laterally extending rim whose body rests primarily along the longitudinal axis of the airway tube will serve this purpose. The flange does not have to be solid, therefore a tubular, mesh or other perforated structure will be perfectly acceptable. The stabilizer preferably has a concave face or area when viewed from the direction depicted in Figure 11, ie from a direction normal to the face of the sleeve, which substantially conforms to the anterior region of the patient's tongue.

It is also possible to form such a rim by widening the profile of the airway tube in the appropriate area, just above the cuff. That is, the oral cavity stabilizer may be an integral part of the airway tube, rather than being a separate component formed in or around the airway tube itself. Therefore, a suitable increase in the overall profile of the airway tube, either formed by the tube itself, or by forming additional material around the tube, can act as a stabilizer.

The overall profile of the buccal cavity stabilizer and how it smoothly engages within the cuff area can be seen in more detail from Figures 16 and 17A and B, which will be described in more detail later in this document. However, it will be appreciated that both weight and plastic material will be saved if the inner diameter or profile of the airway tube is increased or decreased accordingly.

ES 2 395 845 T3 with the width of the stabilizer of the oral cavity. The term internal profile is used because as the airway tube widens it becomes non-circular and instead takes on a substantially elliptical shape. It will therefore be appreciated that in this embodiment the cross-sectional area of ​​the airway tube increases as the width of the buccal cavity stabilizer increases toward its widest point and then decreases again. By maximizing the width of the airway tube it has the potential to increase laminar flow within the device.

A further feature of the airway device depicted in Figure 11 is the two sets of protrusions or bulges 56, 57 and 58, 59 on the face of the cuff. The larger of the two assemblages 56, 57 are adapted to surround the aryepiglottic folds and the piriformis fossa. The smaller of the two 58, 59 are adapted to fit around the thyroid and cricoid cartilages. Furthermore, the tip of the sleeve 55 is a conical soft lip but is preferably not inflated.

A further example is illustrated in Figure 3. This illustrates an airway device 30 provided with a cuff 34 and an oral cavity stabilizer 40. In this case there are two outward bulges or protrusions on either side of the cuff 35, 36 , 38 and 39. An upper set, 38, 39 consisting of a protrusion on each side, is designed to rest around the aryepiglottic folds and the piriformis fossa. The lower assembly 35, 32 is designed to rest around the thyroid and cricoid cartilages. The relative sizes of these bulges will be determined by the appropriate specialist. The bulges 38 and 39, designed to fit around the aryepiglottic folds and the piriformis fossa, are likely to be slightly larger than the two lower bulges. The lower distal end of the cuff is soft but firm and is preferably not pre-inflated or pre-filled to facilitate insertion of the device and is adapted to rest between the larynx and the esophagus. Additional variations are depicted in Figures 4-7, which show the flexibility possible within this general design concept. Figures 6 and 7 illustrate the possibility of including additional molding 60 at the proximal end of the assembly.

Figure 5 illustrates a possible method of manufacturing a device according to the present invention. The device is manufactured from a suitable material as described earlier herein in two halves 81 and 82. The two halves are joined together around an airway tube 83 (not shown for clarity). The airway tube fits into a specially designed channel 84. In this example the buccal cavity stabilizer 90 is integrally molded with the sleeve 94. The tip of the device may contain a series or a plurality of cavities 91, 92 and 93. In this context a plurality means one or more. These cavities increase the flexibility of the tip, which aids in insertion and positioning of the device in use. These cavities also affect the softness and flexibility of the tip, their presence making the tip softer than if it were formed from a solid plastic material. Generally, the softer the material, the lower the potential for damage to the patient's tissue. The overall concave nature of the device is also apparent from Figures 4 and 5.

An additional feature in these examples which is apparent from these figures is that the distal tip of the device tapers towards a moderate point. This conical end is intended to rest or wedge between the larynx and the entrance to the esophagus.

From Figures 4 to 7 inclusive, the understanding of a construction method of an airway device according to the present invention can be appreciated. Basically, the device of Figure 7 is made up of two pieces 61 and 62 plus a molding 64 that includes a 15mm connector or another connector for connecting the device to an anesthetic breathing system. Piece 61 is a ventral or frontal molding, being that part which comes into contact with the entrance of the larynx and the patient's tongue. Piece 62 is a dorsal or posterior molding, the side which is facing away from the ventral part. These definitions of ventral and dorsal are used throughout this specification.

Optionally the device may also include a separate airway tube 63 that is nested within channels 66, 67 formed within the inner body of moldings 62 and 61 respectively. However, in a particular example this separate tube 63 is omitted. In this example tube 63 and moldings 62 and 61 are made from silicone rubber and moldings 64 and 68 from polypropylene. The larger of the two polypropylene moldings 68 is designed to prevent the device from passing into the patient's mouth beyond a certain point.

The airway tube can be of any appropriate diameter, or appropriate cross section, if the tube is not circular. Typically a 9mm tube will be used in an adult version of the airway device.

The moldings 61 and 62 are joined, glued, welded (including, but not limited to, heat welding and laser welding) or otherwise fixed together during assembly. From this simple, elegant and cost-effective form of manufacture it follows that the two components 61 and 62 can be formed from materials with different hardnesses. Therefore the front part of the part 61 containing the laryngeal cuff can be made of a softer material than the rear part. Typical shore hardnesses on the A scale for the front 61 are between 0 and 20, more preferably 0 to 15 and more preferably 4 to 12.

ES 2 395 845 T3

The back 62 has typical Shore hardness values ​​of 20 to 60 and more preferably 30 to 40.

It is possible to incorporate a passage 70 or additional passages within the body of the assembly and along the airway tube. An example of this is illustrated in Figure 8. This step allows other tubes or cables to be passed down the esophagus during use without the need to move or affect the device. For example, orogastric intubation is now possible.

In another variant, shown in Figure 9, the airway incorporates a longitudinal slit that extends substantially the entire length of the passage. This allows other tubes or cables (spark plugs, stylets, etc.) to be inserted or removed during use without the need to affect the mask, during difficult planned or unexpected intubations. Furthermore, this slot arrangement means that the airway device can be released from the tube or cable and removed from the patient leaving the tube or cable in place without being affected.

Figure 10 shows a further embodiment of the present invention and also shows the generally curvilinear shape of the device along its longitudinal axis. This shape is designed to match the opening of the mouth and throat in an anesthetized patient. The longitudinal axis is the axis line represented as a straight dotted line in Figure 10.4 and runs from the proximal end of the airway tube to the distal tip of the cuff.

The general shape of a preferred embodiment of the oral cavity stabilizer is shown in Figure 10.3. The stabilizer, globally represented as 100, is formed around an airway tube 101. However, as described above, a separate tube is not necessary and a tubular passageway may be formed from channels formed within the stabilizer body. The stabilizer portion 102, 103 extends on both sides of the tube 101 in a generally elliptical cross section. It will be appreciated from Figures 10.1 and 10.5 and Figures 17 and 18 that the width of the buccal cavity stabilizer is not uniform and varies along its length. This is in contrast to the airway tubes of similar devices of the prior art, which are generally uniform in cross section. Width in this context is the edge-to-edge dimension in a direction normal to the longitudinal axis of the device and in a plane substantially parallel to the plane of the open face of the sleeve. The stabilizer is narrower at the proximal end of the device, then increases in width to the widest point and then decreases in width again until it butts into the proximal side of the laryngeal cuff. The widest point of the stabilizer therefore is between the proximal end of the airway tube and the proximal end of the laryngeal mask. It is generally advantageous for the widest part to be closer to the end of the laryngeal mask than it is to the proximal end, as shown in Figures 17A and B. This places the widest part closer to the anterior region into use. of the patient's tongue.

Importantly, the height H of the stabilizer does not vary in a similar way. Instead the height remains substantially the same along the longitudinal axis of the stabilizer. This is quite different from conventional airway tubes.

It is evident from the above that the width of the ellipse W at its widest point is greater than the height H at the same point. By way of example, for an adult airway device according to the present invention the width W of the stabilizer, at its widest point, will be in the range 3.5 cm to 4.5 cm and the height H will be in the range range from 1.25 cm to 1.75 cm. A preferred W: H ratio is 2.7 ± 10%.

An important feature of the shape of this stabilizer is the profile of the upper 104 and lower 105 outer surfaces. These are both convex and smoothly curved at their widest areas. This not only makes use easier but, more importantly, the lower surface 105 which comes into contact with the tongue in use, is contoured to follow the shape of the back of the patient's tongue and is sufficiently soft enough to deform to fit it.

A further embodiment is illustrated in Figure 16. In this embodiment the airway tube 111 is only partially contained within the body of the airway device 110. The distal end of the tube passes into and completely through the body of the device for forming a hole within the sleeve 113. In this embodiment, a different profile of the stabilizer is illustrated. In this case the lower surface 115, which in use is in contact with the tongue, is smoothly concave in shape, with the upper surface being globally convex.

Once joined together, the device becomes what is, in effect, a unitary construction. That is, the components become one. This simplifies sterilization, if the device is reusable, and increases reliability.

However, unit construction is not essential. For example, it may be possible to form the oral cavity stabilizer as a separate component (not shown) that is threaded onto, around, or into the tube.

ES 2 395 845 T3 for airway if required. This design will provide the anesthetist with the option of using the device with or without a stabilizer as desired. It will be necessary to incorporate some form of fixation means to fix the stabilizer to both the sleeve and the tube. Fastening means or plastic fastening components are well known, such as snap fit connectors.

This option increases the stabilizer design options. A leaf spring form can be used, attached at one or both ends to the airway tube. Alternatively an inflatable structure can be used. It will be recalled that inflatable cuffs have been used in this context. However, this type of technology has never been used before to incorporate an oral cavity stabilizer into such a device.

Two additional embodiments are illustrated in Figures 17 and 18. These illustrate the unitary, streamlined construction of these embodiments of the invention, with the cuff region 121 butting smoothly within the buccal cavity stabilizer region 122. There are certain other key features depicted in these figures. For example, when the airway tube enters the laryngeal cuff, it does so through three separate openings 123, 124, and 125. This greatly decreases the chance of the airway tube becoming blocked. The shape of the distal end of the stabilizer that joins the proximal end of the sleeve or cup is designed such that when the device is in place, it fits anatomically correctly in and around the vallecula.

The distal tip of the sleeve 126 has been truncated and is in fact now concave in shape. This results in less compressive pressures, which are exerted on the arytenoid and corniculate cartilages, the blood veins, and the nerves supplying the laryngeal body, which is the case with prior art devices. This so-called concave tip can take on a variety of different shapes and profiles. The point may be square such that the end of the point is substantially flat. Or it may be a pronounced indentation at the tip, as depicted in Figure 17A. At the base of that indentation is an opening which forms the end of a passageway in a gastric tube described later in this document. In summary, this truncating is intended to encompass any tip that results in less compressive pressure being exerted than by prior art devices.

A second gastric tube passage, separate from the airway tube, is provided which runs from a hole 127 in the proximal end of the device near connector 128 to a hole in the distal tip of the cuff 129, more clearly depicted in the figure. 17E. The gastric tube allows any gastric aspiration that is detected in the case of passive regurgitation during use. It also provides a route for the insertion of small bore gastric tubes (eg Freka tubes).

A further novel feature of this device is the lip or flange 130 positioned at the proximal end of the sleeve area. This lip is dimensioned and shaped so that it is anatomically positioned against the epiglottis, to ensure a proper seal and to support the retained epiglottis so that it does not fold into the inlet of the larynx avoiding airflow obstruction. This lip takes the form of a sheet-like structure that extends out of the laryngeal cuff and is directed rearwardly toward the proximal end of the airway tube. Its relative size and shape can be seen from Figure 17. The optimal size and shape will be determined by experimentation. Applicant is not aware of any prior art mask containing this feature.

Figure 18 also illustrates certain novel construction and laryngeal cuff features. Returning first to the sleeve, in this embodiment thin, flexible feather-shaped ridges 140 and 141 have been inserted on opposite sides of the sleeve. These are preferably formed as an integral part of the sleeve molding and, due to the very soft nature of the material used to form the sleeve, these ridges are particularly soft and pliable. Its purpose is to allow any variation in the shape of the entrance to the larynx of an individual patient and to contribute to the formation of an efficient and effective joint between the cuff and the laryngeal structures. By this design and by designing the cuff to be a tight anatomical fit, the joint pressure that can be obtained from experimental tests is greater than 30 cm H2O.

The feather-shaped ridges 140 and 141 are depicted in Figure 18 as discontinuous structures but may in fact be interconnected toward the distal end of the sleeve (Figures 18C and D). In this arrangement the ridges 140 and 141 become a single U-shaped rim that extends around most of the perimeter of the laryngeal cuff.

As depicted in Figure 18, it is a two-piece construction. The two pieces are an upper curved part 145, whose outer surface is globally convex, and a lower curved part 146 whose outer surface is globally concave and which includes the face of the laryngeal sleeve which is in use in contact with the inlet of the larynx of the patient. Formed within these two parts is an airway tube channel extending from proximal end 147 to distal end or cuff 149 and the second passage described earlier herein.

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The upper and lower pieces are joined together around the connector 150 using a suitable adhesive or welding technique as selected by those skilled in the art.

The upper part 145 and the lower part may advantageously be formed from materials having different shore hardnesses. Therefore, the upper part can be formed from a material having a Shore hardness in the A scale in the range of 30 to 40, while the lower part can be formed from a softer material with a hardness in the range. range from 4 to 12 on the same scale.

If required, the sleeve area can be formed from a different material and a different hardness than the other parts of the device. This arrangement is shown in Figure 17C where the device is made up of three pieces 135, 136 and 137 instead of two.

However, the elegant and simple design of this airway device allows for an even simpler manufacturing procedure. It has been discovered that the device can be molded as a unitary piece construction in a mold. By properly constructing the mold and carefully considering how the parts can be separated from the mold, a one-piece fabrication is possible. Molding can be produced using a process commonly known as two-injection molding in a molding cycle, in which the materials are injected separately to form the relevant parts of the component. Alternatively, the component can be formed from a material of the same full hardness using a single injection process and if desired by coating all or part of the ventral or dorsal section with a material of a different Shore hardness. The technology for forming such a layer or laminate is known to those skilled in the art.

Returning now to laryngeal cuff design, in the above examples the cuff region has been previously formed from a soft material, or previously filled during manufacture with a fluid. In the latter case, the sleeve coating must be made from a material that does not absorb anesthetic gases such as nitrous oxide, in such a way that the pressure inside the sleeve does not rise during use.

In any alternative variant the sleeve may be formed from a material which is adapted to absorb a liquid, such as for example water, mucus or blood or a similar liquid material and by doing so swell in size so as to conform to the anatomical muco-cartilaginous body at the entrance to the patient's larynx. Such materials will be selected by materials specialists but include cotton rayon blends (CRM) as used in compressed TAMPAX (RTM) or Gel Foam 5 tampons.

In a further alternative example, the cuff may take the form of a conventional inflatable cuff. While this is not ideal due to the inherent disadvantages of inflatable cuffs, the incorporation of an oral cavity stabilizer of the type described above, fabricated from soft materials as described earlier herein, within a device for airway Inflatable laryngeal mask airway represents a significant improvement over and over prior art inflatable masks. The technology for forming an inflatable cuff is well known and does not need to be described in this document.

In summary, the objects and objectives of the present invention are to provide a versatile, reliable, simple and cost-effective anatomically oriented device intended to be used in anesthetized patients who breathe spontaneously or patients recovering from anesthesia, in a certain group of nursing patients. intensive during your ablaction process and during resuscitation to provide a safe airway, Clear and hands-free for the distribution of oxygen or anesthetic gases.

The main objectives and objects are the following:

- Provide a simplified design that has all the advantages of existing airway devices and has anatomically oriented working mechanics in order to establish a clear airway in anesthetized patients who breathe spontaneously, patients in a post-anesthetic recovery phase or certain groups of intensive care patients suffering from ablation of their ventilatory support.

- It avoids almost all the disadvantages and complications of the devices for airways currently used in anesthetic practice.

- It does not require laryngoscopy, intubation or extubation and minimally invades the pharynx-larynx.

- Easy for the user, it will require minimal training for anesthetists, other doctors, nurses, health workers and the rest of the healthcare staff who are likely to use the device.

- A useful tool in the management of an unexpected or anticipated difficult endotracheal intubation. Useful with both an endotracheal tube through the airway and with planned fiberoptic intubation or bronchoscopy.

- Self retention with virtually no need for taping or tying.

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In summary the device has a connector, expanded glossopharyngeal ridges, and a pre-formed anatomically designed laryngeal cup or sleeve, suitable to accurately contour and conform to the entrance to the larynx. However, this should not be construed as preventing this invention from being used with a conventional inflatable cuff, which however does not belong to the invention.

CONNECTOR

A 15mm ISO standard connector suitable to be connected to any gas distribution system used in anesthesia, during post-anesthetic recovery, in intensive care and resuscitation practice.

EXPANDED GLOSOPHARYNGEAL AND ORAL EDGES

All existing airway intubation devices have a variable degree of propensity to tilt to the right or left angle of the mouth, to turn 180 ° around its longitudinal axis, and to move the airway. inward and outward, which can lead to displacement or dislocation of the distal end of the airway thereby rendering it ineffective for the purpose of its use. A combination of the expanded ridges of the device and the construction of the device from a material with a Shore hardness less than 60 on the A scale, allows the oral cavity stabilizer to act as an anchor for the airway device in the position of the midline by tensioning it on the anterior surface of the tongue through the oral cavity and supported laterally by the inner surface, They have the object of a better anchoring of the airway on the tongue. Therefore, not only stabilizing the centrally placed airway device but also holding it against tipping or twisting. Remotely the expanded rim is incorporated within the angled flattened part of the laryngeal cup with the rear lower surface of the tubular part of the device distantly to provide additional anchorage within the narrow hypopharynx.

ANATOMICALLY ORIENTED LARYNGEAL CUP

A soft or preformed rubber cup, previously inflated or previously filled with a suitable liquid or soft material in order not to exert an extra luminal pressure of more than 22 mm HG on the mucosa of the laryngeal inlet and adjacent structures thereby avoiding any compression or shear forces on the pharyngeal-laryngeal mucosa that ensures a continuous uninterrupted flow of blood through the capillaries of the surrounding tissues, thereby ensuring an uninterrupted supply of blood to the structures in contact with it. The anatomically oriented laryngeal cup tightly surrounds the laryngeal inlet without distorting the structures with which it is in contact.

Laterally the outward bulges of the cup or cuff are designed to fit around the alveoli of the aryepiglottic folds and the inferior-lateral piriformis fossa. The conical lower end is to facilitate its passage through the oropharynx which will be provided with a joint above and beyond the interarytenoid fold in the midline and the cuneiform and corniculate cartilages laterally. An upper midline indentation will aid the passage of the cup above the epiglottis without damaging or folding or twisting the epiglottis within the distal socket or hole of the device within the cup. Above the cleft is the flattest piece of the soft cup which is designed for optimal placement in the hypopharynx between the epiglottis and the base of the tongue, thereby separating surrounding structures away from the glottis. Although the cup provides an almost natural and anatomical seal over the glottic orifice, the prevention of aspiration of regurgitated gastric contents cannot yet be guaranteed. Such a risk can be minimized by using a device modified with an esophageal component in high-risk patients.

SIZES

Sizes from 0-7 are contemplated.

<td>1 to 2</td><td>For neonates and babies</td><td>(Weight of 3-20 kilos)</td>

<td> 3</td><td>For children</td><td>(Weight 21-50 kilos)</td>

<td>4 to 5</td><td>For teenagers</td><td>(Weight 51-90 kilos)</td>

<td>6 to 7</td><td>For adults</td><td>(Weight more than 90 kilos)</td>

Reusable or disposable devices can preferably be made of materials as described earlier herein such as latex-free SEBS or medical grade silicone rubber. A reusable device (that can be sterilized) must be capable of at least 40 uses. The simplicity of the design also offers increased ease of sterilization for the purpose of reuse. Disposable devices will be a preferred manufacturing choice which can not only be more economical but are also devoid of any risk of cross infection as may be the case with reusable devices.

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As a result of the above design features, a device according to the present invention is likely to be of much lower cost than any comparable device.

NLA WITH ESOPHAGEAL COMPONENT

The addition of an esophageal component is intended to be used in patients with suspected gastric stasis under anesthesia, in intensive care units, and for patients with highly irritable airways who present a well-recognized and widespread problem of ablation of ventilatory support. Such patients almost certainly end up with a tracheostomy in order to bypass their irritable upper airways to facilitate ablactation. Patients with chronic obstructive and restrictive airways diseases, asthmatics, and heavy smokers are the most likely to present the ablactation problem.

INTUBATION NLA

Morbidity or mortality in patients with anticipated or unexpected difficult intubation is a well recognized aspect of anesthetic practice and a challenging nightmare for any anesthetist when faced with this situation. A modified version of the NLA with a longitudinal slit preformed to the anterior NLA will help facilitate intubation through the NLA with an endotracheal tube with the aid of a spark plug, Cook's airway, or fiberoptic indicator.

OTHERS

Some modifications to the shape, design and working mechanics of each of the NLA components are contemplated, when necessary for an improved performance or aesthetic appearance of the NLA.

The overall airway device can be manufactured as a single piece or each component thereof manufactured separately if deemed necessary in order to improve its function or cost effectiveness or due to any other practical matter.

Legend to figure 1

<td>1st</td><td>Epiglottis</td>

<td>1 B</td><td>Hyoid bone</td>

<td>1 C</td><td>Thyrohyoid membrane</td>

<td>1d</td><td>Corniculate cartilage</td>

<td>1e</td><td>Thyroid cartilage (Adam's apple)</td>

<td>1f</td><td>Arytenoid cartilage</td>

<td>1g</td><td>Cricothyroid ligament</td>

<td>1 hour</td><td>Cricoid cartilage</td>

<td>1i</td><td>Cricotracheal ligament</td>

<td>1k</td><td>Thyroid gland</td>

<td>1m</td><td>Parathyroid glands (4)</td>

<td>1n</td><td>Windpipe</td>

<td>1st</td><td>Tracheal cartilage</td>

<td>1 p</td><td>Epiglottis</td>

<td>1q</td><td>Hyoid bone</td>

<td>1st</td><td>Thyrohyoid membrane</td>

<td>1s</td><td>Thyrohyoid membrane</td>

<td>1t</td><td>Cuneiform cartilage</td>

<td>1u</td><td>Fatty body</td>

<td>1w</td><td>Corniculate cartilage</td>

<td>1x</td><td>Ventricular fold (false vocal cord)</td>

<td>1y</td><td>Arytenoid cartilage</td>

<td>1z</td><td>Thyroid cartilage</td>

<td></td><td></td>

<td>2nd</td><td>Vocal fold (true vocal cord)</td>

<td>2b</td><td>Cricoid cartilage</td>

<td>2 C</td><td>Cricothyroid ligament</td>

<td>2d</td><td>Tracheal cartilage</td>

<td>2e</td><td>Cricotracheal cartilage</td>