GB2567870B

GB2567870B - Nasal endotracheal tube assembly

Info

Publication number: GB2567870B
Application number: GB1717714.8A
Authority: GB
Inventors: Munch Christoph
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-10-27
Filing date: 2017-10-27
Publication date: 2019-11-27
Anticipated expiration: 2037-10-27
Also published as: GB2567870A; GB201717714D0; WO2019081674A1

Description

NASAL ENDOTRACHEAL TUBE ASSEMBLY

Field of the Invention

The present invention relates to a nasal endotracheal tube assembly.

Background Art

There is very good evidence that sedation in intensive care medicine has negative side effects on patients. Sedative drugs lead to immobility, muscle wasting, decreased respiratory drive, decreased gut motility and delirium.

Sedation can lead to increased mortality, prolongs length of stay and increases health care cost.

However, sedation is still needed and widely used to facilitate treatment in intensive care. One of the main reasons why sedation is used in intensive care is for tube tolerance and invasive ventilation. Patients do not tolerate a tube in their windpipe/mouth well, unless sedative drugs (opioids and hypnotics) are used. Patients do tolerate an endotracheal tube much better, if the tube is passed through the nose and therefore less sedation is needed. However, nasal intubation/ventilation was favoured in the past but later became obsolete due to some studies suggesting increased infection rates (sinusitis). The infections were allegedly caused by the large tube blocking the nasal passage and sinus opening, preventing drainage/aeriation of maxillary sinus.

Summary of the Invention

The present invention seeks to provide an improved nasal endotracheal tube assembly and which in practical embodiments can alleviate the problems identified above.

According to an aspect of the present invention, there is provided a nasal endotracheal tube assembly, including: first and second naso-tracheal tubes each having proximal and distal ends and a length; a releasable coupling mechanism disposed along at least a part of the length ofthe tubes, the coupling mechanism being configured to couple the tubes together along at least a part thereof, the coupling mechanism including at least first and second magnetic coupling elements each disposed on a respective one of the first and second naso-tracheal tubes, the first and second magnetic coupling elements being laterally connectible and releasable, whereby the first and second naso-tracheal tubes are separately insertable into a respective nasal passage and coupled together in situ in the trachea by means of the first and second coupling elements.

The provision of two naso-tracheal tubes can ensure that sufficient airflow is maintained without unnecessary blockage of the nasal passages and sinuses.

Preferably, each tube has a flat side, particularly having a flat side and a rounded wall.

In practical embodiments, two corresponding elements of an oximetry device are integrated in the tubes. In preferred embodiments, there are provided at least two oximetry elements, one on each tube.

The assembly preferably includes a cuff disposed at or adjacent one end of the tubes. The cuff is advantageously inflatable and deflatable. In the preferred embodiment, the cuff is formed of first and second cuff sections, each cuff section attached to a respective one of the naso-tracheal tubes.

Advantageously, each naso-tracheal tube has an atraumatic tip.

In practical embodiments, each naso-tracheal tube may incorporate a strengthening element, such as a metal strip or braiding as known in the art.

Preferably, each naso-tracheal tube has an internal transverse cross-sectional area of around 24-28 mm2.

Other features and aspects and their advantages are described below in connection with the specific description.

Brief Description of the Drawings

Embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a side elevational view of an embodiment of endotracheal tube apparatus fitted to a patient in accordance with the teachings herein;

Figures 2a and 2b are cross-sectional views of a preferred embodiment of tubes for the apparatus of Figure 1;

Figure 3 is a cross-sectional view showing the tubes of Figures 2a and 2b at the level of a cuff of the apparatus;

Figure 4 is a transverse cross-sectional view showing the tubes at and beyond the position of the nasal septum;

Figures 5a and 5b show views of the two tubes of the apparatus in different orientations; and

Figures 6a and 6b show two states of the cuff of the apparatus.

Description of the Preferred Embodiments

The description and accompanying drawings describe a preferred embodiment of nasal endotracheal apparatus according to the teachings herein. The skilled person will appreciate that the drawings are not necessarily to scale and also that they are schematic only.

Referring first to Figure 1, this shows the apparatus fitted to a patient. The apparatus includes first and second naso-tracheal tubes 10A and 10B fitted through the patient’s nose on either side of the nasal septum and into the patient’s trachea. The naso-tracheal tubes 10A, 10B extend from outside the patient’s nose to below the vocal chords and end at a cuff 12, described in further detail below.

The apparatus also includes a magnetic locking pad 14 positioned along the tubes 10A, 10B so as in use to be located in proximity to the patient’s soft palate. A zone 16 of oximetry is located proximal of the magnetic locking pad 14, passing light through the nasal septum and measuring oxygen saturation and pulse (pulse oximetry). The electrical wiring connections and pads are not shown in Figure 1 for the sake of clarity, though these will be readily apparent to the person skilled in the art.

There are also provided a subglottic suction port 18 and a pilot line 20 of known form and function. In Figure 2 only a single pair 18, 20 is shown, and in practice there would be provided a corresponding pair in each of the tubes 10A, 10B.

Referring now to Figure 2a, this shows a cross-sectional view of a preferred embodiment of the naso-tracheal tubes 10A, 10B. These are preferably D-shaped in cross-section and in this embodiment have an outer width of around 6.5 mm and an outer depth of around 5.5 mm, and have an internal cross-sectional area of preferably between 24-28 mm2. It will be appreciated that together the two tubes 10A, 10B will have a combined cross-sectional area of 48-56 mm2, deemed enough for the passage of sufficient air to and from the patient.

The tubes 10A, 10B preferably have uniform dimensions and therefore cross-sectional areas along the entire of their lengths, although it is not excluded that there may be one or more zones or increased or reduced cross-sectional area.

In Figure 2a, there is shown, fitted into a recess 24 of the flat wall portion 26 of the tube 10A, 10B a magnetic pad or strip 14. In practice, each tube 10A, 10B will be provided with at least one magnetic pad 14, which are disposed in opposing relationship so as to be attractive to one another. The skilled person will appreciate that there may be provided a single magnetic pad or strip 14 on each tube 10A, 10b but there may equally be provided a plurality along the length of each tube 10A, 10B beyond the position of the septum in order to provide a plurality or length of tube attachment positons. It is preferred that where a plurality of pads 14 is provided, that these are longitudinally spaced from one another and advantageously by more than the longitudinal length of each pad 14, such that the tubes 10A, 10B can be differentially moved relative to one another in such a manner that facing pads 14 are no longer longitudinally aligned, thereby to break the magnetic attraction between them and as a result to facilitate the fitting and removal of the tubes 10A, 10B to and from the patient.

Referring to Figure 2b, this shows a cross-section of one of the tubes 10A, 10B to show the oximetry pad 16, which in this embodiment is positioned so as to overlie the flat wall 26 of the tube 10A, 10B. In the preferred embodiment, there is provided an oximetry pad 16 on each of the tubes 10A, 10B. As the oximetry pads 16 can be of a conventional type and known to the skilled person, it is not disclosed in further detail herein.

Figure 3 shows a cross-section ofthe tubes 10A, 10B at the location ofthe cuff 12. In this embodiment, the assembly includes a two part cuff, formed of first and second cuff elements 12A, 12B. The cuffs are inflatable and deflatable via pilot lines 20. The subglottic suctioning (Fig 5b, 18A and 18B) is not depicted here as its opening is above the level of the cuff.

Figure 4 shows a cross-section view of the tubes 10A, 10B at the location of the nasal septum. As can be seen, oximetry sensors or pads 16 are disposed on each of the tubes 10A, 10B and are positioned either side of the nasal septum (soft pads ensure good contact with nasal septum and plethysmography). In practice, the nasal tubes 10A, 10B are inserted through the left and right nostrils and joined in the epi-pharynx. Magnetic pads 14 on each of the tubes 10A, 10B are disposed downstream ofthe oximetry elements 16 and are magnetically attracted to one another so as to bond the tubes 10A, 10B together (upstream magnetic pads may be useful in helping oximetry pads to make good contact with septum). As explained above, there is preferably provided a plurality of pairs of magnetic pads 14 disposed at spaced intervals along the tubes 10A, 10B. The arrangement, as the skilled person will appreciate, is such that the tubes 10A, 10B abut along their flat sides 26.

Figures 5a and 5b show the tubes in different orientations, Figure 5a with the flat sides 26 ofthe tubes 10A, 10B facing one another and Figure 5b showing the flat sides rotated by 90 degrees so as to face out of the paper. The cuff 12A, 12B, which may be made of a (preferably memory) foam material, can be seen in its two parts or elements 12A, 12B, each attached to and extending around a respective tube 10A, 10B, apart from at the flat side 26. Each tube preferably has an atraumatic end 32A, 32B, typically of rounded form and in some embodiments coated or made of soft material.

As can be seen in Figure 5b, each tube 10A, 10B includes an oximetry pad 16 and a plurality of magnetic pads 14. The pilot and subglottic suction lines 18, 20 are advantageously attached to the tubes 10A, 10B along their lengths.

Figures 6a and 6b shows the cuff sections 12A, 12Bin deflated and inflated conditions. It will be apparent that when inflated, the cuff sections 12A, 12B will close the trachea save for air passage through the tubes 10A, 10B. In the preferred embodiments, the first and second cuff sections 12A and 12B include corresponding facing surfaces 24A, 24B that abut closely to one another when the cuff sections are inflated. Most preferably, the corresponding facing surfaces 24A, 24B of the first and second cuff sections are substantially flat and together provide an uninterrupted cuff barrier, as will be apparent particularly from Figures 1 and 3.

As will be apparent form the above, instead of providing just one oral endotracheal tube, the proposed apparatus uses two smaller calibre tubes 10A, 10B that can be passed separately through left and right nostril/nasal passages and meet in the oropharynx, from where they enter the trachea and facilitate ventilation. The smaller calibre tubes 10A, 10B make use of advances in materials and manufacturing of tubes allowing for better lumen/wall ratio. As there are two tubes 10A, 10B the calibre of the tubes can be smaller (inner diameter about 4.5-5.2 mm) and thus will not block the maxillary sinus. The tubes are advantageously kink-resistant, such as by being wire or braiding enforced tubes with reduced wall thickness of down to 0.2 mm. Structures of such a nature are known in the catheter art and have also been described in the literature.

The two small tubes 10A, 10B together can allow as much airflow as one larger tube normally does. Specifically, two tubes each of about 4.5 to 5.2 mm inner diameter will provide sufficient combined airflow (around 30-40 l/min), especially if augmented with pressure support and automatic tube compensation.

The improved tube tolerance will allow reduction or omission of sedative drugs and facilitate spontaneous breathing modes and faster weaning of ventilator support.

The two tubes 10A, 10B pass either side of the vomer/nasal septum and then join to form a y-shape and lock the device in position (as shown in Figures 1 and 4). Should the patient accidentally pull on the tubes 10A, 10B, then the y-shape double lumen tube will reduce the risk dislodgement. Pain is inflicted at the back of the nose when the bifurcation of the device is pulled towards the nasal septum/vomer, this will deter the patient from pulling at the tubes 10A, 10B.

As described above, the apparatus includes a pair of naso-tracheal tubes 10A, 10B, each with a D-shaped lumen. The flat sides 26 of the D of each tube 10A, 10B have incorporated pieces of magnetic strips 14 which are poled North/South in way that the tubes 10A, 10B are attracted to each other over the length of the tubes. The magnetic strips 14 are preferably thin and flush with adjacent tube material (as can be seen particularly in Figure 2a). The magnetic strip 14 is advantageously divided into small sections not to impact on bending qualities of the tube particularly at the back of the nose. For the same reason the profile of the tubes 10A, 10B is that of a small height letter D keeping the flat side relatively short.

Both tubes 10A, 10B are inserted nasally after induction of anaesthesia -one through each nostril. Both tubes 10A, 10B can be visualized during laryngoscopy. When they appear in the pharynx, the operator/intensivists guides/rotates the two tubes 10A, 10B, preferably by means of Magill’s forceps in order to align the ends 32A, 32B and magnetic strips 14. The joined up tubes 10A, 10B are then advanced and guided through the vocal cords in to the windpipe (trachea). The two aligned cuffs 12A, 12B are then inflated and provide a water tight seal preventing aspiration (as can be seen in particular in Figures 1 and 3).

At the back of the nasal septum, where both tubes 10A, 10B approach each other, a y-shape is formed (Fig 4). This zone is characterized by increasing/decreasing magnetic forces which depend on the distance between the magnets 14. This zone is similar to a zipper opening/closing adapting to the patients anatomy. It also allows the tubes 10A, 10B to be removed easily as the magnetic forces weaken when the tubes are pushed apart by the septum when pulled out (see Figure 4).

The magnet patches 14 are preferably of balanced strength that is strong enough to hold the tubes together but able to separate readily when additional force is applied. An on/off switch (that is, mechanical switch changing north/south pole) for stronger magnets is another option that could lock the tubes 10A, 10B in position and can be released in an emergency. This would be an optional magnetic locking/unlocking device. Magnetic holding with electric switch control is another option as miniaturized products already exist and could be used to lock and release the tubes elegantly. FIG 4 and 2b depict the septal oximetry, where integrated in the tubes are soft pads of flexible material providing pulse oximetry to measure the pulse/heart rate and oxygenation of the patients’ blood. Light is passed through the nasal septum by the emitting side and measured at the opposing pad of tube on the other side of the septum. This arrangement will help position the tube correctly and make pulse oximetry measured at the patient’s finger obsolete. (Finger oximetry is cumbersome as it falls off frequently or is taken off by the patient, has artefacts due to movement, has cables lying in the patient’s bed and is prone to false alarms). The connections of septal pulse oximetry can be arranged with the ventilator tubing and are therefore tidied away from patients reach. A split cuff 12A, 12B design is preferred because a common cuff could otherwise be an obstacle at the septum when the two tubes 10A, 10B are pulled out. Both tubes 10A, 10B have corresponding D-shaped halves of a “high volume low pressure cuff” (HVLP-cuff). The cuff is preferably made from self-expanding foam/memory foam material. The foam material has an outer layer of airtight material allowing the cuffs 12A, 12B to be in an evacuated/collapsed state during insertion and extraction. The cuffs are then aeriated and expand slowly when the pilot line/balloon is opened (as can be seen in Figure 6) or can actively inflated with an air-filled syringe. The two halves preferably form a cone-shaped cuff. The pilot line is used to deflate the cuff prior intubation or prior extubation.

The tube design should advantageously incorporate existing well known features like sub-glottic suctioning, a-traumatic bevelled tip, Murpheys eye, silver coating and high volume low pressure cuff with pilot balloon.

The benefits of the apparatus include, by way of non-limiting example: • Better patient comfort and reduced need for sedation leading to: • reduced mortality and healthcare cost • reduced risk of accidental extubation due to optional pharyngeal locking mechanism (additional magnet as described above) • reduced chance of tube dislodgement • improved patient oral hygiene • reduced lip, tongue and skin trauma • easier fixation of tube/tubes • if one tube blocks, the patient can still be ventilated through the second tube • reduced number of patients will require tracheotomy (creating artificial airway through surgery) • making cumbersome finger oximetry redundant • added functionality by using the septum/vomer for measuring: oxygen saturation, heart rate, tissue perfusion and possibly temperature

The apparatus can also provide for other medical advantages. For example, reduced dead-space ventilation can be achieved due to smart use of flow direction (would require special ventilator device). Flow during expiration could be reduced or blocked in one tube resulting in positive end-expiratory pressure (PEEP). PEEP is a commonly used concept in intensive care. If expiratory flow can be blocked in one of the tubes, than the next inspiration-cycle starts with zero carbon dioxide (CO2) in that tube hence reducing “dead space”. Reduced dead space can be beneficial by reducing respiratory work load.

While the tubes 10A, 10B preferably have flat sides 26 that abut one another along a part of the length of the tubes, in other embodiments the tubes 10A, 10B may have other cross-sectional shapes including, round, oval, polygonal and so on. Flat sides are, however, preferred and providing stable connection of the tubes 10A, 10B to one another.

Claims

1. A nasal endotracheal tube assembly, including: first and second naso-tracheal tubes each having proximal and distal ends and a length; a releasable coupling mechanism disposed along at least a part of the length of the tubes, the coupling mechanism being configured to couple the tubes together along at least a part thereof, the coupling mechanism including at least first and second magnetic coupling elements each disposed on a respective one of the first and second naso-tracheal tubes, the first and second magnetic coupling elements being laterally connectible and releasable, whereby the first and second naso-tracheal tubes are separately insertable into a respective nasal passage and coupled together in situ in the trachea by means of the first and second coupling elements.

2. A nasal endotracheal tube assembly according to claim 1, wherein the first and second coupling magnetic elements are located along a part of the length of their respective naso-tracheal tube and are connectible together when aligned with one another and separable when non-aligned to one another.

3. A nasal endotracheal tube assembly according to claim 1 or 2, including a plurality of sets of first and second magnetic coupling elements disposed in discrete locations along the length of the first and second endotracheal tubes.

4. A nasal endotracheal tube assembly according to any preceding claim, wherein each tube has a flat side.

5. A nasal endotracheal tube assembly according to any preceding claim, wherein each tube has a flat side and a rounded wall.

6. A nasal endotracheal tube assembly according to any preceding claim, including an oximetry element coupled to each of the tubes, providing an oximetry device.

7. A nasal endotracheal tube assembly according to any preceding claim, including a cuff disposed at or adjacent the distal end of the tubes.

8. A nasal endotracheal tube assembly according to claim 7, wherein the cuff is inflatable and deflatable.

9. A nasal endotracheal tube assembly according to claim 7 or 8, wherein the cuff is formed of first and second cuff sections, each cuff section attached to a respective one of the naso-tracheal tubes.

10. A nasal endotracheal tube assembly according to claim 9, wherein the first and second cuff sections include corresponding facing surfaces that abut one another when the cuff sections are inflated.

11. A nasal endotracheal tube assembly according to claim 10, wherein the corresponding facing surfaces of the first and second cuff sections are substantially flat.

12. A nasal endotracheal tube assembly according to any preceding claim, wherein each naso-tracheal tube has an atraumatic tip.

13. A nasal endotracheal tube assembly according to any preceding claim, wherein each naso-tracheal tube comprises a strengthening element.

14. A nasal endotracheal tube assembly according to any preceding claim, wherein each naso-tracheal tube has an internal transverse cross-sectional area of 24-28 mm2.