GB2472403A

GB2472403A - Endotracheal tube with hinged portion

Info

Publication number: GB2472403A
Application number: GB0913592A
Authority: GB
Inventors: Michael Mccooe
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-08-04
Filing date: 2009-08-04
Publication date: 2011-02-09
Also published as: GB0913592D0; WO2011015811A1

Abstract

An endotracheal tube 10 comprising an expandable hinge portion 13,14, wherein the expandable hinge portion 13,14 is flexible when expanded, and substantially rigid when contracted. The expandable hinge portion 13,14 is expanded upon insertion of a rod 30 e.g. endoscope. The tube 10 further comprises at least one control wire 17 which can cause deflection of the tube 10 and compress the tube 10 by compressing the hinge 13,14. In another aspect, an endoscope comprises a flange 31 for cooperation with a distal portion 21 of an endotracheal tube 10, and a connector portion 31c for cooperation with a proximal portion 21 of the endotracheal tube 10.

Description

Endotracheal Tube

Field of the Invention

This application relates to an endotracheal tube in general. This application also relates to an intubation system. This application further relates to a method of intubation. This application further still relates to an endoscope.

Background

Intubation is the process whereby an endotracheal tube is placed directly into the trachea (windpipe) of an anaesthetised or unconscious patient via the mouth or nose. Once intubated, the patient breathes through the endotracheal tube. Figure 1 shows an intubated patient I with the airways in cross section.

Intubation is performed on the anaesthetised or unconscious patient I for various reasons. The process is usually uncomplicated and is performed with the use of a laryngoscope 2. A standard laryngoscope 2 comprises a handle and a blunted, curved or straight blade 3 at approximate right angles to the handle. It has a fibre optic light source that emanates from the distal end of the blade.

The supine patient us approached from the head end, the optimal patient position is obtained, and the blunted blade 3 of the laryngoscope 2 is placed carefully into the patient's mouth 4. The laryngoscope 2 is used to sweep the tongue to the side of the mouth, and then to raise the lower jaw and associated soft tissues of the upper airway. In an uncomplicated intubation, this action will provide a clear view of the vocal cords. An endotracheal tube 5 can then be passed through the vocal cords into the trachea 6, at which point an inflatable cuff at the distal end of the tube can be inflated to provide a seal in the trachea 6 and secure the airway. Ventilation through this secure airway can then be commenced.

Intubation is performed in order to maintain an open and secure airway in a patient that is unable to do this for themselves. lntubation ensures that the gas exchange of normal ventilation is allowed to take place. Once intubated, a patient can be artificially ventilated with a mechanical ventilator or allowed to breathe spontaneously through the tube.

There are many situations in which the placement of an endotracheal tube is required either for protection of the airway or for the proper control and monitoring of the patient's gas exchange. The airway needs to be protected for example if there is a risk of aspiration of stomach contents. This is more likely to occur in obstetric surgery, intraobdominal surgery (particularly laparoscopic surgery), if the patient has a recent history of vomiting or reflux, if the patient is obese, and in emergency surgery where the patient has not been starved prior to the commencement of anaesthesia. The specific type and area of surgery can dictate that intubation is necessary, for example in intrathoracic surgery and other upper airway surgery.

A further occasion in which it is necessary to protect the patient's airway is after trauma. An endotracheal tube will prevent aspiration of blood and other debris that may have resulted from a traumatic incident. When there is airway swelling which may be prone to deterioration, for example in anaphylaxis, abscess formation, trauma and thermal injuries (fire), it is essential that the airway is kept open with an endotracheal tube.

Many factors can cause difficulties during the intubation process. In a difficult intubation, the view obtained on introduction of the laryngoscope blade into the mouth can be considerably restricted. The restricted view can vary from a view in which the vocal cords are partially covered by the epiglottis to one in which the epiglottis, which overlies the vocal cords, cannot even be viewed.

Indeed, it may be the case that the laryngoscope cannot be introduced into the patient's mouth due to obstruction, trauma, swelling or limited mouth opening.

There are many reasons why the process of intubation can be difficult and these circumstances can conveniently be categorised into those that are predicted to be difficult and those in which the difficulty is unexpected.

A difficult intubation can be predicted if the patient has obvious anatomical or functional issues. For example if the patient has a mouth abscess of upper airway swelling a good view is less likely on the introduction of a laryngoscope. A disorder at the jaw joint (temperomandibular joint) or a tooth abscess can limit the opening of the mouth and thus preclude the use of a standard laryngoscope. With regards to the patient's neck, arthritis or other musculoskeletal disorders can prevent the movements required to obtain the optimal patient position for intubation and thus make it difficult or indeed impossible to intubate without the use of further specialist equipment. Trauma patients also pose difficulties. The need to maintain the cervical spine (neck) in a neutral alignment to prevent any spinal cord injury means that the optimal position for intubation cannot be obtained. Trauma, thyroid swelling and cancer in the upper airway can all distort anatomy to the extent that normal laryngoscopy and intubation are impossible. As well as these gross anatomical and functional issues, difficult intubation can often be predicted in patients with a small or shortened jaw bone, in those with prominent teeth, patient's with short necks and in those with large tongues as occurs for example in Down's syndrome.

Various clinical indicators are used to identify those patients who may not have any obvious issues as described above but can indeed prove to be difficult to intubate. Assessment of a patient's mouth opening, their ability to protrude their lower jaw and the limits of their neck extension are used, amongst other things, to try and predict a difficult intubation. In spite of the various techniques and observations employed, the majority of those intubations that prove to be difficult are not predicted.

When an unexpected difficult intubation is encountered, there are various algorithms advocating different techniques and equipment that can provide a resolution. The most important factor in all of this, however, is that the anaesthetized or unconscious patient is promptly ventilated and provided with the oxygen necessary to maintain the normal function of their various organs.

Failure to provide proper ventilation in a timely fashion can result in organ damage and ultimately death. There are different techniques and devices that can be employed to intubate patients predicted to be difficult and those in whom problems have not been foreseen.

When an intubation has been forecast to be problematic the optimum procedure is an awake fibre optic intubation. This involves the use of a flexible fibre optic laryngoscope that has a steerable tip that can be manipulated to deflect in two directions. The flexible fibre optic laryngoscope is manipulated through the vocal cords and into the trachea of an awake patient. A pre-loaded' endotracheal tube is then passed over the endoscope and into the trachea. This process may be referred to as railroading the endotracheal tube into position.

This technique can be very difficult and requires a significant amount of expertise. The equipment required is very delicate and expensive and therefore not suitable for field use. It is not available on short notice and many hospitals have a limited number of flexible fibre optic laryngoscopes.

Furthermore, after use a flexible fibre optic laryngoscope must be sterilized requiring a lengthy process. This can be a disincentive for use and also can significantly reduce the number of flexible fibre optic laryngoscopes that are available for use at any one time. All of the above factors dictate that this equipment and technique are not suitable for use in an emergency situation.

An intubation device is required which allows for intubation in difficult cases, but which can be made readily available to medical personnel throughout a hospital and even by paramedics outside of a controlled environment.

Summary

There is provided an endotracheal tube comprising an expandable hinge portion, wherein the expandable hinge portion is flexible when expanded, and substantially rigid when contracted, An intubation system is provided when an endoscope is inserted into the endotracheal tube. The endotracheal tube further comprises control wires which can be used to deflect a distal portion of the endotracheal tube when the expandable hinge portion is rendered flexible.

Accordingly, the endoscope used is flexible or partially flexible but does not require internal mechanical means to steer it. In this way a manoeuvrable intubation system is provided using a simple and relatively cheap endoscope.

Once the endotracheal tube is positioned in the airway, the expandable hinge portion is contracted, rendering the endotracheal tube substantially rigid. This helps prevent kinking of the endotracheal tube and so ensures that a secure airway is maintained for the patient.

There is provided an endotracheal tube comprising an expandable hinge portion, wherein the expandable hinge portion is flexible when expanded, and substantially rigid when contracted.

An endotracheal tube having a two state expandable hinge portion allows for the endotracheal tube to have different characteristics for placement of the tube and for operation in securing the airway. In a first state, the expandable hinge portion is rendered flexible, allowing the distal portion of the endotracheal tube to be deflected during intubation. This allows the tip to be steered around obstructions. In a second state, the expandable hinge portion is rendered substantially rigid, helping to ensure a secure airway for the patient.

The expandable hinge portion may be expanded upon insertion of a rod. The rod may be flexible. The rod may have a flexible portion arranged to coincide with the expandable hinge portion when the rod is inserted into the endotracheal tube. The rod may be an endoscope.

The expandable hinge portion is arranged to flex around a flexible rod inserted into the endotracheal tube. Accordingly, an endoscope having an appropriately positioned flexible portion can be used within the endotracheal tube to allow the operator to see any obstructions in the airway.

Where the rod is not an endoscope, the endotracheal tube may be used with a laryngoscope to allow the operator to view the position of the endotracheal tube while using the control wires to deflect the tip as required while passing the endotracheal tube through the airway.

The endotracheal tube may further comprise control wires, the control wires arranged to apply compression between a distal portion and a proximal portion of the endotracheal tube. Compression applied by a control wire may cause deflection of a distal portion of the endotrachea tube by contracting one side of the expandable hinge. Control wires may be arranged on a posterior side and an anterior side of the endotracheal tube allowing bi-directional deflection of the distal portion of the endotracheal tube.

Compression applied by a control wire may cause an increase in the curvature of the endotracheal tube where the expandable hinge is contracted.

The rod may be arranged to flex in one plane, said plane arranged coincident with the plane of the control wires within the endotracheal tube. Where the rod is flexible in a first plane, it may be substantially inflexible in a second plane, perpendicular to the first.

The control wires allow for the distal portion of the endotracheal tube to be deflected, allowing the tip of the endotracheal tube to be steered around obstructions in the airway during intubation.

Thus, an intubation system is provided in which the distal portion is steerable, but which utilizes a simple endoscope. The endotracheal tube may be disposable and accordingly an inexpensive intubation system is provided which may be utilized in unexpected difficult intubations and that is

appropriate for field use.

The expandable hinge may be contracted by application of compression on opposite sides of the endotracheal tube by both control wires. The expandable hinge portion may be contracted by applying tension to the control wires. A fastening means may be provided on each control wire to provisionally fix a deflection of the distal portion of the endotracheal tube.

Using the control wires to contract the expandable hinge portion, in conjunction with the control wire fastening means, allows the expandable hinge portion to be locked in a contracted state, in which it is substantially rigid. This ensures a secure airway.

The control wires may be mounted within a wall of the endotracheal tube. The control wires may be fixed to the distal portion of the endotracheal tube. The control wires may emerge at a proximal end of the endotracheal tube. The control wires may be radio opaque.

Where the control wires are radio opaque, they will show up on an X-ray image, allowing for verification of correct endotracheal tube placement.

The expandable hinge portion may be contracted by at least one elastic member which is stretched when the expandable hinge portion is expanded.

The elastic member may comprise a sleeve circumferentially fixed to a surface of the endotracheal tube at both a distal portion and a proximal portion. An elastic member may be provided at both an interior surface and an exterior surface of the endotracheal tube.

The expandable hinge portion may comprise: a break in the wall material of the endotracheal tube, the break separating a distal portion and a proximal portion of the endotracheal tube; and an elastic sleeve circumferentially fixed to a surface of the endotracheal tube at both a distal portion and a proximal portion.

The expandable hinge portion may comprise: a corrugated section of the wall material of the endotracheal tube, the corrugated section separating a distal portion and a proximal portion of the endotracheal tube. The expandable hinge portion may be surrounded by an inflatable cuff.

The inflatable cuff is known in the field of endotracheal tubes, and may be inflated after insertion of the endotracheal tube to secure its position and secure the airway. Positioning the inflatable cuff and the expandable hinge at a coincident point on the endotracheal tube allows the cuff to provide additional physical support to the flexible hinge portion.

The inflatable cuff is inflated via a hole within the wall and along the length of the proximal portion of the endotracheal tube. An outlet is provided at an external surface of the endotracheal tube, within the inflatable cuff section.

The outlet allows air to pass from the hole into the cuff. By placing the inflatable cuff over the extendible hinge, the outlet may be provided on the proximal portion of the endotracheal tube. This obviates the need for an inflation path through the extendible hinge portion.

A flange may be provided at a distal end of the endotracheal tube, the flange for receiving the rod. The flange may cause the expandable hinge portion to be expanded upon insertion of the rod into the endotracheal tube. A fixing means may be provided at a proximal end of the endotracheal tube, the fixing means for fixing the rod to the endotracheal tube with the expandable hinge portion expanded. The fixing means may be a clamp. The fixing means may be a screw fitting. The fixing means may be a bayonet fitting. The bayonet fitting may comprise at least one protrusion on the side of the rod and at least one "J" shaped slot on the endotracheal tube.

The flange allows the expandable hinge to be rendered flexible upon insertion of an appropriately sized rod. The expandable hinge can be provisionally fixed in the flexible state with the use of a fixing means between the rod and the endotracheal tube to ensure the rod remains fully inserted. This is advantageous if an elastic member is arranged to bias the expandable hinge to the contracted state.

A two stage fixing means may be provided having at least two positions along the length of the rod that the endotracheal tube can be fixed to. In a first position the expandable hinge is expanded, and in a second position the expandable hinge is contracted. Selection of either the first or second position allows an operator to select whether deflection caused by tension in the control wires is applied at the expandable hinge, or along the length of the endotracheal tube.

The endotracheal tube may include at least one Murphy's eye at the distal portion. A Murphy's eye is a hole cut into the side of a distal portion of the endotracheal tube. The Murphy's eye functions as a side vent allowing ventilation of the patient should the end opening of the endotracheal tube be blocked or pressed against an object preventing air flow.

There is further provided an intubation system comprising an endotracheal tube having an endoscope inserted therein; the endotracheal tube comprising an expandable hinge portion, wherein the expandable hinge portion is flexible when expanded, and substantially rigid when contracted; and the endoscope comprising a shaft for insertion into the endotracheal tube, wherein at least a part of the endotracheal tube adjacent to the expandable hinge portion is flexible.

There is further provided an endoscope for use with an endotracheal tube, the endoscope comprising a flange for cooperation with a distal portion of an endotracheal tube, and a connector portion for cooperation with a proximal portion of the endotracheal tube.

The endoscope may be substantially flexible. The section of the endoscope between the flange and the connector portion may be substantially flexible.

The endotracheal tube may have a hinge portion and the section of the endoscope adjacent the hinge portion when the endoscope is inserted into the endotracheal tube may be flexible. Where the endotracheal tube is arranged to flex in a plane, the endoscope may also be flexible only in a plane, the flexible plane of the endoscope arranged coincident with the flexible plane of the endotracheal tube when the endoscope is inserted into the endotracheal tube. Where the endoscope is flexible only in a first plane, it may be substantially inflexible in a second plane, perpendicular to the first.

Where the endoscope is arranged to be flexible only in one plane, the structural integrity of the intubation system, comprising the endotracheal tube with the endoscope inserted is improved. This results in the forces applied via the control wires being more efficiently applied to the expandable hinge portion of the endotracheal tube.

There is further provided a method of intubating using an endotracheal tube having an endoscope inserted therein, the endotracheal tube comprising an expandable hinge portion, wherein the expandable hinge portion is flexible when expanded, and substantially rigid when contracted, the method comprising: inserting an endoscope into the endotracheal tube and expanding the expandable hinge portion; guiding the endotracheal tube into position in an airway, using the endoscope; and removing the endoscope from the endotracheal tube.

The method may further comprise using control wires in the endotracheal tube to apply compression between a distal portion and a proximal portion of the endotracheal tube.

The method may further comprise using control wires in the endotracheal tube to selectively deflect a distal portion of the endotracheal tube. This may allow the tip of the endotracheal tube to be steered around obstructions in the airway during intubation.

There is further provided a method of intubating using an endotracheal tube, the endotracheal tube comprising an expandable hinge portion, wherein the expandable hinge portion is flexible when expanded, and substantially rigid when contracted, the method comprising: inserting an endoscope into the endotracheal tube and expanding the expandable hinge portion; inserting the endotracheal tube into the mouth or nose of a patient; viewing the position of the endotracheal tube in the patient's airway, using the endoscope; guiding the endotracheal tube into a desired position using control wires in the endotracheal tube to deflect a distal position of the endotracheal tube, and removing the endoscope from the endotracheal tube.

The method may further comprise locking the expandable hinge portion in a contracted state by pulling the control wires and applying fastening means to them. The method may further comprise inflating a cuff located towards the distal end of the endotracheal tube. The method may further comprise inserting a guide strip into the endotracheal tube along side the endoscope.

The method may further comprise: extending the guide strip through the endotracheal tube into the desired position; and sliding the endotracheal tube over the guide strip into the desired position.

The guide strip may be elastically deformable. An elastically deformable guide strip extends straight out from the tip of the endotracheal tube, even if the endotracheal tube is curved. Accordingly, the guide strip may be positioned using the endotracheal tube and the endoscope, the guide strip may then serve as a guide to direct the endotracheal tube into position.

Using the endoscope to position the guide strip is advantageous over blind intubation using a bougie because the latter gives rise to significant risk of trauma to the patient's airway.

The guide strip may be preloaded into the endotracheal tube, with an endoscope, prior to insertion into the patient, allowing for one handed operation

Brief Description of the Drawings

Embodiments will now be described, by way of example only, with reference to the following drawings, in which: Figure 1 shows an intubated patient with the airways in cross section; Figure 2 shows an endotracheal tube; Figure 3 shows a cross section of the endotracheal tube taken across line HI -III shown in Figure 2; Figure 4 shows a view of the proximal end of the endotracheal tube, the view position labelled IV in Figure 2; Figure 5 shows the endotracheal tube with an endoscope inserted therein; Figure 6 shows the proximal end of the endotracheal tube and endoscope viewed from the distal end, the view position labelled VI in Figure 5; Figure 7 shows a view of the distal end of the endotracheal tube and endoscope, the view position labelled VII in Figure 5; Figure 8 shows the endotracheal tube with the expandable hinge portion contracted; Figure 9 shows an alternative endotracheal tube and endoscope inserted therein; Figure 10 shows a view of the distal end of the alternative endotracheal tube and endoscope, the view position labelled X in Figure 9; Figure 11 shows a view of the proximal end of the alternative endotracheal tube and endoscope, the view position labelled XI in Figure 9; Figure 12 shows an alternative endotracheal tube featuring an inflatable cuff arrangement; Figure 13 shows a cross section of the endotracheal tube of Figure 12, the cross section taken across line XIII -XIII shown in Figure 12; and Figure 14 shows an alternative endotracheal tube having corrugated hinge sleeves.

Detailed Description of the Drawings

Current practice in those situations in which a difficult intubation is encountered but not anticipated involves the use of various devices and adjuncts that can make the task easier. A steerable fibre optic scope is not appropriate given its long set up time and need for the presence of a skilled practitioner.

If the patient can be adequately ventilated by mask ventilation, with or without the help of other airway devices, the operator has some time to perform the procedure provided the airway is not at risk of further compromise and so long as there is no risk of aspiration (fluids entering the lungs). In this situation, and dependent upon the view obtained using a laryngoscope, a bougie or stylet can be used in order to locate the glottis and hence the trachea.

Either a bougie or a stylet can act as a guide for the placement of an endotracheal tube. These devices may be plastically dêformable, and so can be bent into a desired shape. Based on the operator's knowledge of the airway and on the view obtained in direct laryngoscopy, the likely position of the vocal cords can be estimated. The guiding device can then be shaped by hand and introduced by feel' into the trachea. There are many potential pitfalls to this procedure. Firstly, blind' placement of the endotracheal tube can result in trauma to the airway. This is particularly serious if there already exists trauma or swelling in the airway that may deteriorate and cause complete obstruction. Secondly, as one has no direct visualisation of the endotracheal tube passing through the vocal cords, the failure rate is high and this often leads to oesophageal intubation. The oesophagus 7 is shown in figure 1. Oesophageal intubation not only wastes vital moments during which time the patient is riot receiving any oxygenation but also can cause insufflation of the stomach which due to a mass effect will make subsequent ventilation more difficult. Furthermore, this may increase the likelihood of gastric aspiration. Thirdly, as it involves the introduction of a standard laryngoscope into the mouth, it is not suitable for patients having limited or restricted mouth opening.

If the patient cannot be ventilated (can't intubate, can't ventilate; CICV), then it is important that a secure airway is created as quickly as possible. Any trauma or swelling inflicted by the use of a blind device can lead to deterioration in the calibre of the airway, and ultimately to complete airway obstruction. This situation would prove fatal if not remedied within a short period of time, by for example, the opening of a surgical airway. Accordingly it is important to perform intubation as quickly as possible and with the minimum amount of resultant trauma.

There exist many controflable stylets that use either fibre optics or camera technology to transmit an image from the distal end of the endoscope to an eyepiece or a viewing screen at the proximal end of the device. These stylets can be mounted within an endotracheal tube and used to guide the structure as a single unit through the vocal cords and into the trachea. These controllable stylets are expensive and, due to the existence of some intricate mechanics, are fragile. These are not suitable for use in the field i.e. outside the controlled hospital environment.

Figure 2 shows an endotracheal tube 10. The endotracheal tube 10 has a tubular body that is curved and subtends an angle of around 30 degrees. The endotracheal tube has a distal opening which is at an angle, the opening forming an ellipse, the opening inclined towards the left side of the tubular body, when viewed towards the inside of the curve of the tubular body. The opening is inclined towards the left side of the patients body, as the endotracheal tube is inserted into the patient The tubular body further comprises a proximal portion 11 and a distal portion 12. Hinge sleeves 13, 14 join the proximal portion 11 and distal portion 12 and create a flexible hinge portion. Inner hinge sleeve 13 joins the inner surfaces of the prqdmal portion 11 and distal portion 12. Outer hinge sleeve 14 joins the outer surfaces of the proximal portion 11 and distal portion 12.

Inner hinge sleeve 13 has an outer diameter equal to the inner diameter of the tubular body. Outer sleeve 14 has an inner diameter equal to the outer diameter of the tubular body. The hinge sleeves 13, 14 are joined to the surface of the tubular body by seals 15. The seals 15 may be formed by glue ora thermal or chemical weld. The hinge sleeves 13, 14 comprise an elastic material substantially impermeable to air. The hinge sleeves 13, 14 are arranged such that they are elastically stretched when the distal portion and proximal portion of the tubular body are separated.

Control wires 16, 17 are provided within the tubular body. Control wire 16 is positioned along the inside of the curve of the tubular body. Control wire 17 is positioned along the outside of the curve of the tubular body. The control wires 16, 17 are fixed to the distal portion 12 at fixing points 18. The control wires 16, 17 emerge from the face of the distal portion 12, pass between the inner hinge sleeve 13 and the outer hinge sleeve 14, and enter the opposing face of the proximal portion 11. Control wires 16, 17 emerge from the proximal portion 11 via eyelets 19 in the wall of the proximal portion a distance from the proximal end of the proximal portion 11. A loop 20 or some other form of handle means is provided at the exposed end of each control wire 16, 17. Eyelets 19 are provided to reinforce the wall of the proximal portion 11 where the control wires emerge from the tubular body. The control wires 16, 17 are radio-opaque for easy identification of tube position in a chest radiograph.

The proximal end of the proximal portion 11 has a pair of proximal fixing projections 21. Proximal fixing projections 21 extend outwardly from the wall of the tubular housing at the proximal end. A proximal fixing projection 21 is positioned on the inside and on the outside of the curve of the tubular body.

The distal end of the distal portion 12 has a pair of distal fixing projections 22.

Distal fixing projections 22 extend inwardly from the wall of the distal portion 12 of the tubular housing. A distal fixing projection 21 is positioned on the inside and on the outside of the curve of the tubular body. Distal fixing projections extend around a limited portion of the inner circumference of the tubular housing in order to present reduced impedance to airflow through the tubular housing.

In an alternative embodiment, the distal fixing projection 22 comprises an annular flange extending inwardly from the wall of the distal portion 12 of the tubular housing.

Figure 3 shows a cross section of the endotracheal tube 10 of Figure 2, the cross section taken across line III -III shown in Figure 2. Control wires 16 and 17 pass through channels 23 within the wall of the tubular housing. The diameter of the channel 23 is sufficient to allow the wires 16, 17 to move freely within them.

Figure 4 shows a view of the proximal end of the endotracheal tube 10, the view position labelled IV in Figure 2. The wall of the proximal portion 11 of the endotracheal tube 10 is shown with the proximal fixing projections 21 extending outwardly therefrom.

Figure 5 shows an intubation system comprising the endotracheal tube 10 with an endoscope 30 inserted therein. The endoscope 30 has a lens or other optics at a tip at the distal end which collects an image. The tip of the endoscope 30 also includes a light source to assist in the collection of an image when the endoscope is within the body of a patient. The image is passed along the length of the endoscope 30 to a display such as an eyepiece or a video screen at the proximal end. Endoscope 30 is flexible along its length such that when it is inserted into the endotracheal tube 10, its curvature follows that of the endotracheal tube 10. Endoscope 30 has an engagement mechanism 31 which cooperates with the proximal fixing projections 21 of the endotracheal tube 10. The engagement mechanism 31 is fixed to endoscope 30 such that the endoscope 30 cannot slide through the engagement mechanism 31. The engagement mechanism 31 comprises flange portion 31a which extends outwardly from the endoscope 30, at least one collar portion 31 b which extends distally from the flange portion 31 a, and two engagement elements 31 c which extend inwardly from the at least one collar portion 31 b, back towards the endoscope 30, without meeting it. The separation distance of the facing surfaces of the engagement elements 31 c is greater than the outer diameter of the proximal portion 11 of the tubular body.

The separation distance of the facing surfaces of the engagement elements 31 c is less than the distance between the opposing outer faces of the proximal fixing projections 21.

The engagement mechanism 31 is arranged to receive and engage with the proximal fixing projections 21 so as to releasably connect the endoscope 30 to the endotracheal tube 10.

Figure 6 shows the proximal end of the endotracheal tube 10 and endoscope viewed from the distal end, the view position labelled VI in Figure 5. The engagement mechanism 31 is shown engaged with the proximal fixing projections 21. A recess 33a is provided in the proximal fixing projections 21.

Further, a protrusion 33b is provided on the engagement mechanism 31. The protrusions and recesses 33 engage with each other so as to secure the engagement mechanism 31 in position on the proximal fixing projections 21.

In an alternative embodiment, protrusions 33b are provided on the proximal fixing projections 21 and recesses 33a are provided in the engagement mechanism 31.

As shown in Figure 5, endoscope 30 further comprises an annular flange 32 for cooperation with the distal fixing means 22 of the endotracheal tube 10.

The annular flange 32 is positioned near the tip of the endoscope 30. The outer diameter of the annular flange 32 is greater than the separation distance of the facing surfaces of the distal fixing means 22.

Figure 7 shows a view of the distal end of the endotracheal tube 10 and endoscope 30, the view position labelled VU in Figure 5. Annular flange 32 is shown extending circumferentially around the endoscope 30. Distal fixing projections 22 extend inwardly from the distal portion 12 of the tubular body.

In the arrangement shown the annular flange 32 engages with the distal fixing means 22 regardless of the relative orientation of the endotracheal tube 10 and endoscope 30.

In operation, the endoscope 30 is inserted into the proximal end of the endotracheal tube 10. The tip of the endoscope 30 and the annular flange 32 pass along the length of the proximal portion 11 of the tubular body, through the flexible hinge portion, and along the distal portion 12 of the tubular body until the annular flange 32 engages with the distal fixing projections 22. The distal fixinc projections 22 are arranged so as not to interfere with the illumination or image collection operations of the endoscope 30. The endoscope 30 is pushed further into the proximal portion 11 of the tubular body, separating the distal portion 12 from the proximal portion 11 and stretching the inner and outer hinge sleeves 13, 14. The hinge sleeves 13, 14 operate to provide a biasing force pulling the proximal portion 11 and the distal portion 12 together in the event that they are separated.

The endoscope 30 is pushed into the proximal portion 11 until the flange portion 31a of the engagement mechanism 31 abuts against the proximal fixing projections 21 of the endotracheal tube 10. For this to occur, the engagement mechanism 31 must be arranged in an unengaged orientation relative to the proximal fixing projections 21 of the endoscope 30. That is, in the unengaged orientation the engaging elements 31c are aligned with the spaces between the proximal fixing projections 21. Once fully inserted into the endotracheal tube 10, the end oscope 30 is rotated relative to the endotracheal tube 10 such that the engagement mechanism 31 engages with the proximal fixing projections 21, and the recesses and protrusions 33 thereon interlock. Thus, the intubation system is rendered in a deployment state where the expandable hinge portion is expanded and rendered flexible.

In the deployment state a control wire 16 or 17 can be pulled relative to the distal portion 11 of the tubular body and the tension applied thereto causes the distal portion 12 of the tubular body, and the tip of the endoscope 30 therein, to deflect in the direction of that control wire. With reference to the orientation of Figure 5: pulling loop 20 of control wire 16 will cause the distal portion 12 of the tubular body to deflect upwards; and pulling loop 20 of control wire 17 will cause the distal portion 12 of the tubular body to deflect downwards.

When the intubation system is in the deployment state, the endoscope 30 allows an operator to see a view from the tip of the endotracheal tube 10.

This allows the operator to see the structures in the vicinity of the tip of the endotracheal tube 10. In this way, the operator can use the control wires 16, 17 to steer the tip of the endotracheal tube 10 around any obstacles in a patient's airway. Further, the patient need not be in the optimum position for intubating because the operator does not need to visualise the vocal chords from the mouth opening using a laryngoscope but can instead simply pass the endotracheal tube 10 and endoscope 30, in the deployment state, into the mouth or nose of the patient and visualize the vocal chords using the endoscope 30. Pushing the endotracheal tube 10 further into the patient's mouth or nose while the vocal chords are visualised in the centre of the view obtained by the endoscope will cause the endotracheal tube 10 to pass through the vocal chords. Similarly, if any other blockage is encountered, the control wires 16 and 17 can be used to aim the tip of the endotracheal tube 10 around the blockage before the endotracheal tube 10 is inserted further into the patient.

The inner and outer hinge sleeves 13, 14 expand with deflection of the distal portion 12 allowing the internal diameter of the tubular body to be maintained even when flexed at the expandable hinge portion.

Further, if a blockage to one side is encountered, the endotracheal tube 10 can be rotated relative to the patient such that lateral deflection of the distal portion 12 using a control wire 16 or 17 can be effected.

Control wires 16 and 17 can also be used to provide an increase or decrease in the general curvature of the tubular body of the endotracheal tube 10. If a tension is applied to both control wires 16 and 17 at the same time, with more tension on one wire than the other, then a deflection can be caused along the length of the end otracheal tube 10, the deflection not focussed at the expandable hinge portion. This function is useful with particularly difficult anatomy in oral intubation.

Similarly, if the engagement mechanism 31 is disengaged from the proximal fixing projections 21, the expandable hinge portion is contracted, and a tension applied to both control wires 16 and 17 to keep the expandable hinge portion contracted, then an increased tension in one of the wires 16, 17 will cause a deflection along the length of the endotracheal tube 10, providing an increase or decrease in the general curvature of the tubular body.

The intubation system comprising an endotracheal tube 10 and an endoscope can be used with or without the assistance of a laryngoscope. If used without a laryngoscope, this will reduce the usual stress response of a patient to intubation. Further not using a laryngoscope reduces the cost of the intubation procedure by not requiring cleaning or disposal of a laryngoscope blade. The endotracheal tube 10 can be placed orally or nasally. Steering of the distal tip 11 allows the endotracheal tube 10 to be positioned correctly when the patient has very limited mouth opening. Further, optimal head and neck position of the patient is not required so the endotracheal tube may still be positioned in situations where the patient has suffered trauma, or is arthritic, for example. Further, the operator does not need to be behind head of supine patient, as is the case with standard laryngoscopy. Accordingly, an unconscious patient trapped in a car seat may be intubated and ventilated using the system.

According'y, the intubation system comprising the endotracheal tube 10 with the endoscope 30 therein is steered into the trachea of the patient. As the intubation system enters the trachea, accurate placement can be verified by visualisation of the bronchi and carina. The carina is where the trachea splits into the two primary brQnchi. Once positioned in the trachea, the endotracheal tube 10 is used to secure the patient's airway. The engagement mechanism 31 is disengaged from the proximal fixing projections 21 and the endoscope 30 is withdrawn from the endotracheal tube 10. A standard 15 mm connector is then inserted into the proximal end of the endotracheal tube 10, the 15mm connector for attachment of the endotracheal tube 10 to a breathing circuit.

Figure 8 shows the endotracheal tube 10 with the expandable hinge portion contracted. Upon disengagement of the endoscope 30, the inner and outer hinge sleeves 13 and 14 elastically contract and operate to contract the expandable hinge portion. Control wires 16 and 17 can be used to apply additional force to contract the expandable hinge portion. The control wires 16 and 17 have toggles 24 mounted thereon between the loop 20 and the eyelet 19. The toggles 24 may be used during insertion of the endotracheal tube 10 into the patient's airway to assist in obtaining the desired deflection of the endotracheal tube 10 or the distal portion 12 thereof. However, with the expandable hinge portion contracted, the control wires 16, 17 are pulled taught and the toggles 24 are used to lock them in position such that expandable hinge portion remains contracted.

Should the operator desire, once the endotracheal tube 10 is locked with the expandable hinge portion contracted, the proximal portion 11 may be trimmed.

The proximal portion 11 may be cut at any point between the eyelets 19 and the proxima' fixing projections 21.

Ensuring the expandable hinge portion remains contracted ensures a secure airway for the patient by reducing the occurrence of kinking or twisting of the endotracheal tube 10 about the flexible hinge portion.

An advantage of using an elastic material for the inner hinge sleeve 13 is that when the expandable hinge portion is contracted the inner hinge sleeve 13 does not restrict the internal diameter of the endotracheal tube 10, allowing for unrestricted airflow through the expandable hinge portion.

An alternative embodiment of the endotracheal tube 10 is shown in Figure 9.

In this embodiment the endotracheal tube 10 is modified for use with a guide strip 40. The guide strip 40 passes through the endotracheal tube 10 adjacent to the endoscope 30 and against the wall of the tubular body adjacent the outside of the curve of the tubular body. Some modification to the system is required to allow this to happen.

Figure 10 shows a view of the distal end of the endotracheal tube 10 and endoscope 30, the view position labelled X in Figure 9. Distal fixing projections 22 are arranged on opposite sides of the distal portion, on an axis perpendicular to that of the control wires. Annular flange 32 has a segment missing in order to allow the guide strip 40 to pass through.

Figure 11 shows a view of the proximal end of the endotracheal tube 10 and endoscope 30, the view position labelled XI in Figure 9. Engagement mechanism 31 has a section cutaway to allow the guide strip 40 to pass through. A segment is missing of the engagement mechanism 31 which abuts the endoscope 30, or at least has a reduced thickness, and a segment is missing of flange portion 31 a to allow the guide strip 40 to pass through.

The missing sections described above are arranged such that the guide strip can remain in position with the endoscope engaged or disengaged with the endotracheal tube 10. In this way, the endoscope 30 can be disengaged from the endotracheal tube 10 with the guide strip 40 kept in position.

The handle of the endoscope 30 is also adapted for use with the guide strip such that the guide strip 40 can run past the handle while parallel, or substantially parallel, to the shaft of the endoscope 30 The guide strip 40 is a deformable strip which can be used to railroad an endotracheal tube into position. It is possible that the endotracheal tube 10 and endoscope 30 can be positioned such that the endotracheal tube 10 is pointing at a desired aperture within the airway, but that the endotracheal tube cannot be pushed to or through said aperture without causing injury to the patient. In such circumstances the guide strip 40 can be pushed through the endotracheal tube 10 at and through the aperture, the endotracheal tube 10 can then be railroaded over the guide strip 40 through the aperture and into the desired position. That is, the guide strip 40 is used as a guide over which the endotracheal tube 10 is slid. It may be necessary to disengage the endoscope 30 from the endotracheal tube 10 to allow the railroading.

The guide strip 40 is pre-mounted in the endotracheal tube 50 alongside the endoscope 30. The guide strip 40 is flexible but has a tendency to return to the straight position when not under tension. The guide strip 40 may be elastically deformable. Thus when the vocal cords and trachea are visualised but cannot be reached through normal advancement of the tube, (due to anatomical distortion, swelling, or trauma, for example) the guide strip 40 is advanced in the straight direction to pass through the vocal cords. If the vocal cords are in the centre of the visual field as viewed with the endoscope 30, a deployed guide strip 40 will pass directly through them and into the trachea.

This is then used as a guide over which the endotracheal tube 50 is passed.

The guide strip 40 may be hollow so as to allow passage of drugs or oxygen, the latter appropriate for jet ventilation.

Figure 12 shows an alternative endotracheal tube 60 featuring an inflatable cuff arrangement. An inflatable cuff 65 is joined to the tubular housing along two circumferential seals, either side of the flexible hinge portion. Figure 12 shows a cross section of the endotracheal tube 60 with the expandable hinge portion contracted 8nd the cuff 65 inflated. When inflated, the cuff 65 has an external diameter around twice the diameter of the tubular body. The cuff 65 is inflated via an air passage 66 in the wall of the proximal portion 11 of the tubular body. A hole is provided between the air passage 66 and the inside of the cuff 65, through the outer side of the proximal portion 11 of the tubular body, at a position between the proximal seal of the cuff 65 and the proximal seal 15 of the outer hinge sleeve 14.

Figure 13 shows a cross section of the endotracheal tube 60 of Figure 12, the cross section taken across line XIII -XIII shown in Figure 12. Figure 13 shows channels 23 and control wires 16, 17 therein. Figure 13 also shows air passage 66 in the wall of the tubular body.

Returning to Figure 12, air passage 66 receives air via connecting tube 67 which connects a pump 68 to the endotracheal tube 60. Pump 68 includes at least one valve to ensure that once inflated the cuff 65 remains inflated. The pump 68 may comprise a syringe. Connecting tube 67 connects to air passage 66 at around the same position along the length of the endotracheal tube 60 as the eyelets 19.

As explained previously, once inflated the cuff 65 operates to hold the endotracheal tube 60 in position. The cuff 65 further operates to seal the airway preventing the aspiration of fluids which may become present in the throat of the patient. Further still, the pressure within the inflated cuff 65 may serve to pull the distal portion 12 towards the proximal portion 11, assisting in the contraction of the expandable hinge portion.

Having both an outer hinge sleeve 14 and an inner hinge sleeve 13 reduces the risk of herniation of the expandable hinge portion to the inside of the endotracheal tube 60 upon inflation of the cuff 65.

Figure 14 shows an alternative embodiment of an endotracheal tube 70 having corrugated hinge sleeves 73, 74. An inner corrugated hinge sleeve 73 and an outer corrugated hinge sleeve take the place of the inner hinge sleeve 13 and outer hinge sleeve 14 in any of the previous endotracheal tube embodiments. The corrugated hinge sleeves 73, 74 are sealed to the tubular body in a similar manner and arrangement as elastic hinge sleeves 13, 14 described above in connection with Figure 2.

The corrugated hinge sleeves 73, 74 operate in a manner similar to a hinged drinking straw. In some arrangements, corrugated hinge sleeves 73, 74 do not apply a biasing force bringing together the distal portion 12 and the proximal portion 11. In such arrangements, the expandable hinge portion is contracted by operation of the control wires 16, 17 alone. The corrugated hinge sleeves 73, 74 exhibit improved pressure resistance with a reduced propensity for ballooning.

In further alternatives, one of the inner and outer hinge sleeves is corrugated and the other is elastic. In particular, in one embodiment an endotracheal tube has an elastic inner hinge sleeve 13 and a corrugated outer hinge sleeve 74.

In yet further alternatives, only one hinge sleeve is provided, either only on the inside of the endotracheal tube or only on the outside of the endotracheal tube. The only one hinge sleeve may comprise either elastic, corrugated, or ine'astic material.

The control wires 16, 17 may be a metal wire, a nylon thread, or some other flexible thread like material. Where the control wires are not radio opaque, a separate radio opaque element may be provided. Such a radio opaque element may comprise a metal wire embedded along the length of the tubular body opposite the air passage 66. Alternatively, such a radio opaque element may comprise an at least one metallic component embedded in the distal portion 12 of the tubular body.

The endotracheal tube's described above have fixing projections 21, 22 for cooperating with the endoscope 30. Any type of fixing means may be substituted for these projections. For example, a clamp or friction fitting may be used to connect the endoscope to the endotracheal tube. Alternatively, a bayonet fitting may be used having projections from the endoscope provided for cooperation with a slot in the wall of the endotracheal tube. Further, retractable projections may be provided at the tip of the endoscope for cooperating with recesses in the wall of the distal portion of the endotracheal tube, the retractable projections operated by a control at the proximal end of the endoscope.

The tubular body of the endotracheal tube is manufactured from polyvinylchloride (PVC), ivory PVC or siliconized PVC. These materials allow smooth passage of the endotracheal tube through the airways with limited trauma. Further, these materials have been appropriately implantation tested.

The elastic hinge sleeves 13, 14 may comprise a rubber such as non-latex, Butyl, treated silicone, or Thermoplastic Vulcanizate (TPV). These are glued or welded across the divided tube.

At least one elastic hinge sleeve 13, 14 may be connected to the endotracheal tube in a stretched state such that the hinge sleeve applies a biasing force between the proximal and distal portions of the tubular body when the expandable hinge portion is contracted. A sufficient length of the hinge sleeve material is provided such that the hinge sleeve can be further stretched upon insertion of a rod or endoscope into the endotracheal tube to allow for expansion of the expandable hinge portion.

In an embodiment, the endoscope 30 is a basic fibre optic scope that includes illumination fibres having a proximal end positioned against a light source.

The endoscope 30 has a handle at the proximal end, and the light source is positioned in the handle. The light source is battery powered by a battery also carried in the handle. Thus, the endoscope 30 is portable and suitable for use in the field by, for example, paramedics. No moving parts are required in the endoscope 30 and it can therefore be produced at low cost, yet be more robust than a controllable stylet and easily cleaned. The absence of moving parts within the endoscope 30 renders it more robust and so suitable for use in demanding environments beyond a hospital. In a further embodiment a sheath is placed over the endoscope before the endoscope is inserted into the endotracheal tube. The sheath reduces contamination of the endoscope and may negate need for formal cleaning after use.

In an alternative embodiment, the endoscope viewing arrangement may comprise a camera and small screen.

The above described endotracheal tubes are intended to be single use or disposable. In conjunction with a simple endoscope 30, an intubation system is provided which can be readily available and easy to load, therefore appropriate for emergency situations or unexpected difficult intubations.

The above described intubation system is easy to use with minimal training and so can be made available in theatres, resuscitation rooms and ambulances. The intubation system may be operated by a single person, and one handed intubation is possible. The intubation system is of particular use to paramedics, whom often have to intubate difficult patients in difficult positions and conditions.

In an embodiment, the endoscope has semi-malleable proximal section and fully flexible distal section that correlates in length with the expanded expandable hinge portion of the endotracheal tube. This arrangement provides increased flexibility to the intubation system in the vicinity of the expandable hinge portion.

The endotracheal tube's described above can be fabricated in different external diameters to suit different uses. For example, an endotracheal tube having internal diameter of 8-9mm would be used for oral intubation of an adult male, an endotracheal tube having internal diameter of 6 mm would be used for nasal intubation of an adult woman, and an endotracheal tube having internal diameter of 2 mm would be used for intubation of an infant. Of course, an adult can be intubated with a smaller diameter endotracheal tube, such as 6.5 mm internal diameter.

Embodiments of the claimed invention have been described with particular reference to the examples illustrated. However, it will be appreciated that variations and modifications may be made to the examples described without departing from the scope of the claims.

Claims

Claims 1. An endotracheal tube comprising an expandable hinge portion, wherein the expandable hinge portion is flexible when expanded, and substantially rigid when contracted.
2. An endotracheal tube according to claim 1, wherein the expandable hinge portion is expanded upon insertion of a rod.
3. An endotracheal tube according to claim 2, wherein the rod has a flexible portion arranged to coincide with the expandable hinge portion when the rod is inserted into the endotracheal tube.
4. An endotracheal tube according to claim 2 or 3, wherein the rod is an endoscope.
5. An endotracheal tube according to any preceding claim, further comprise at least one control wire, the control wire arranged to apply compression between a distal position and a proximal position of the endotracheal tube.
6. An endotracheal tube according to claim 5, wherein compression applied by a control wire causes deflection of a distal portion of the endotracheal tube by contracting one side of the expandable hinge.
7. An endotracheal tube according to claim 5 or 6, wherein control wires are arranged on a posterior side and an anterior side of the endotracheal tube, allowing bi-directional deflection of a distal portion of the endotracheal tube.
8. An endotracheal tube according to claim 5, 6 or 7, wherein the rod is arranged to flex in one plane, said plane arranged coincident with the plane of the at least one control wire within the endotracheal tube.
9. An endotracheal tube according to claim 5, wherein the expandable hinge is contracted by applying tension to the at least one control wire.
10. An endotracheal tube according to any of claims 5 to 9, wherein a fastening means is provided on each of the at least one control wires.
11. An endotracheal tube according to any preceding claim, wherein the expandable hinge portion is contracted by an at least one elastic member, the at least one elastic member stretched when the expandable hinge portion is expanded.
12. An endotracheal tube according to any preceding claim, wherein the expandable hinge portion comprises a break in the wall material of the endotracheal tube, the break separating a distal portion and a proximal portion of the endotracheal tube; and an elastic sleeve circumferentially fixed to a surface of the endotracheal tube at both a distal portion and a proximal portion.
13. An endotracheal tube according to any preceding claim, wherein the expandable hinge portion comprises: a corrugated sleeve, the corrugated sleeve joining a distal portion and a proximal portion of the endotracheal tube.
14. An endotracheal tube according to any preceding claim, wherein the expandable hinge portion is surrounded by an inflatable cuff.
15. An endotracheal tube according to any preceding claim, further comprising a fixing projection on an internal surface at a distal end of the endotracheal tube, the fixing projection for abutting against a distal end of the rod.
16. An endotracheal tube according to any preceding claim, further comprising a fixing means at a proximal end of the endotracheal tube, the fixing means for fixing the rod to the endotracheal tube with the expandable hinge portion expanded.
17. An endotracheal tube according to any preceding claim, further comprising at least one Murphy's eye at the distal portion.
18. An intubation system comprising an endotracheal tube having an endoscope inserted therein; the endotracheal tube comprising an expandable hinge portion, wherein the expandable hinge portion is flexible when expanded, and substantially rigid when contracted; and the endoscope comprising a shaft for insertion into the endotracheal tube, wherein at least a part of the endoscope adjacent to the expandable hinge portion is flexible.
19. An intubation system according to claim 18, further comprising a guide strip inserted in the endotracheal tube.
20. An endoscope for use with an endotracheal tube, the endoscope arranged to be inserted into the endotracheal tube, the endoscope comprising a flange for cooperation with a distal portion of an endotracheal tube, and a connector portion for cooperation with a proximal portion of the endotracheal tube.
21. An endoscope according to claim 20, the endoscope for cooperating with an endotracheal tube having an expandable hinge portion.
22. An endoscope according to claim 21, the endoscope arranged to expand the expandable hinge portion of the endotracheal tube when the connector portion of the endoscope is engaged with the proximal portion of the endotracheal tube.
23. An endoscope according to claim 21 or 22, the endoscope further comprising a flexible portion arranged to be adjacent to the expandable hinge portion when the connector portion of the endoscope is engaged with the proximal portion of the endotracheal tube.I
24. An endoscope according to claim 21, 22 or 23, wherein the flexible portion is flexible in a first plane but substantially inflexible in a second plane perpendicular to the first.
25. An endoscope according to claim 24, wherein the first plane coincides with a control plane of the endotracheal tube when the connector portion of the endoscope is engaged with the proximal portion of the endotracheal tube.
26. An endoscope according to any of claims 21 to 25, wherein the flexible portion extends along the length of the endoscope within the endotracheal tube when the endoscope is inserted therein.
27. An endoscope according to any of claims 21 to 26, the endoscope further comprising a substantially inflexible portion.
28. A method of intubating using an endotracheal tube, the endotracheal tube comprising an expandable hinge portion, wherein the expandable hinge portion is flexible when expanded, and substantially rigid when contracted, the method comprising: inserting an endoscope into the endotracheal tube and expanding the expandable hinge portion; inserting the endotracheal tube into the mouth or nose of a patient; viewing the position of the endotracheal tube in the patient's airway, using the endoscope; guiding the endotracheal tube into a desired position using control wires in the endotracheal tube to deflect a distal position of the endotracheal tube, and removing the endoscope from the endotracheal tube.
29. A method according to claim 28, the method further comprising locking the expandable hinge portion in a contracted state by pulling the control wires and applying fastening means thereto.
30. A method according to claim 28 or 29, the method further comprising inflating a cuff located towards the distal end of the endotracheal tube.
31. A method according to claim 28, 29 or 30, the method further comprising inserting a guide strip into the endotracheal tube along side the endoscope.
32. A method according to claim 31, the method further comprising: extending the guide strip through the endotracheal tube into the desired position; and sliding the endotracheal tube over the guide strip into the desired position.