This invention relates to viewing means of the kind having a bendable rod with a bore extending along its length and a camera assembly including a camera unit located at the forward end of the rod and attached with one end of a cable extending along the bore, the opposite end of the cable being attached with an elongate electrical connector.

The invention is more particularly concerned with viewing assemblies for use in placing apparatus within a patient such as inserting an endotracheal tube into the trachea. Traditional introducers or bougies take the form of a simple rod that can be bent to an approximate desired shape and can flex to accommodate the shape of the anatomy during insertion. The introducer may be made with an angled, Coude tip to facilitate introduction. The introducer can be inserted more easily than the tube itself because it has a smaller diameter and can be bent and flex to the ideal shape for insertion. The small diameter also gives the clinician a better view of the trachea around the outside of the introducer. These bougies may be used with or without the aid of a laryngoscope. When the bougie has been correctly inserted, a tube can be slid along the outside of the bougie to the correct location. The bougie is then pulled out of the tube, which is left in position. Bougies are available from Smiths Medical. GB2312378 describes an introducer or bougie moulded of an aliphatic polyurethane material and also describes an earlier bougie made from a braided polyester filament repeatedly coated in layers of resin. The characteristic flexural and recovery properties of these bougies is highly valued by clinicians.

More recently it has been proposed to use fibre optics or a CCD camera with an introducer to provide the clinician with a view of the trachea as the introducer is inserted. WO2007/089491 describes an arrangement with an introducer and a separate camera assembly clipped onto the outside of the introducer, which is removed before an

endotracheal tube can be slid along the introducer. Alternative arrangements have a handle at the machine end of the introducer so that the apparatus has to be inserted with the tube already loaded on the introducer from its patient end. Such arrangements are more difficult to use because of the presence of the tube during insertion. WO2010/136748 describes an introducer arrangement with a camera at one end of an introducer and connected via a cable to a display screen at the opposite end. The introducer is disconnected from the display when correctly positioned so that an endotracheal tube can be slid along the introducer into position, following which the introducer is removed by pulling rearwardly from the endotracheal tube.

It is particularly important that these video introducers or bougies retain the flexural and recovery properties of conventional bougies, even after sterilisation and prolonged storage. If the diameter of the bore along the bougie has to be enlarged to accommodate the viewing means this can adversely affect the handling properties of the bougie. Another problem is that it can be difficult to connect the cable with an electrical connector at the rear end of the bougie. If the cable length is extended beyond the bougie to allow access for connection to a connector there can be surplus cable but no space within the bougie to receive this. Providing a video introducer or bougie at a reasonable cost with all the characteristics needed is not a trivial problem.

It is an object of the present invention to provide alternative medico-surgical viewing assemblies.

According to one aspect of the present invention there is provided viewing means of the above-specified kind, characterised in that the viewing means includes a sleeve having its forward end attached with the outside of the rear end of the rod and enclosing a length of the cable extending between the rod and the connector, and that the rear end of the sleeve is attached with the connector.

The sleeve may be of a rigid plastics material. The rod preferably has a reduced diameter portion at its rear end forming a step, the forward end of the sleeve extending along the reduced diameter portion up to the step. The electrical connector may be in the form of a plug having a plurality of axially spaced contact regions. The camera unit may be located within an enlarged recess at the patient end of the bore. The camera unit may be sealed in the recess by cap means, the cap means having a transparent window at a forward end face and a cylindrical wall extending between the outside of the camera unit and the inside of the rod in the enlarged recess. The cap means preferably has an external rim forming a step, the step abutting the forward end of the rod and the external diameter of the rim being matched to the external diameter of the rod. The transparent window may be provided by a plate of a transparent material or by a filling of a transparent fluid solidified in space between the cap means and the camera unit.

According to another aspect of the present invention there is provided viewing means having a bendable rod with a bore extending along its length and a camera assembly including a camera unit located at the forward end of the rod and attached with one end of a cable extending along the bore, the opposite end of the cable being attached with an elongate electrical connector, characterised in that the camera unit is located in a recess at the forward end of the rod, and that the camera unit is sealed in the recess by cap means having a transparent window at a forward end and having a cylindrical wall extending between the outside of the camera unit and the inside of the rod in the recess.

The transparent window may be provided by a plate of a transparent material or by a filling of a transparent fluid solidified in space between the cap means and the camera unit. The cap means may have an external rim forming a step, the step abutting the forward end of the rod and the external diameter of the rim being matched to the external diameter of the rod.

According to a further aspect of the present invention there is provided a method of making viewing means including the steps of providing a bendable rod having a bore extending along its length, providing a camera assembly comprising a camera unit and a cable attached at its forward end with the camera unit, threading the rear end of the cable along the bore until its rear end emerges from the rear end of the rod, electrically connecting the rear end of the cable with an elongate electrical connector, subsequently extending a sleeve to enclose the length of cable between the rear end of the rod and the connector, and joining one end of the sleeve with the rear end of the rod and the opposite end of the sleeve with the connector.

The sleeve preferably locates on a stepped region at the rear end of the rod such that the viewing means has a substantially constant diameter along the rod and sleeve. According to a fourth aspect of the present invention there is provided viewing means made according to the method of the above further aspect of the present invention.

A video introducer for endotracheal tube placement and its method of manufacture, according to the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 shows an assembly of viewing means in the form of a video introducer and an endotracheal tube;

Figure 2 is a cross-sectional side elevation showing the introducer before full assembly;

Figure 3 is an enlarged cross-sectional side elevation showing a cap used to close the forward end of the introducer;

Figures 3A to 3C are enlarged cross-sectional side elevation views showing different embodiments of the forward end cap; and

Figure 4 is a cross-sectional side elevation showing the machine end of the introducer after full assembly.

With reference first to Figures 1 and 2, the assembly consists of viewing means or a video introducer 1 extending within an endotracheal tube 2. The introducer 1 is in the form of a flexible, bendable plastics rod or bougie 10 about 700mm long with an outside diameter of about 5mm. Typically, the rod 10 is extruded and has a coaxial bore 11 extending along its length. The bore 11 is enlarged at the forward end 12 of the rod to form a cylindrical recess 13 that is about 14mm long and 4mm in diameter. A short region 14 at the forward end of the recess 13 has a slightly larger diameter for a reason that will become apparent later. The enlarged recess 13 could be formed by drilling or by other conventional techniques. The rear, machine end 15 of the rod 10 is formed with a stepped region 16 that has a reduced external diameter of about 4mm extending for a distance of about 10mm. The region 16 may be formed by milling, grinding or any other conventional technique. The region 16 provides an external, rearwardly-facing step 17 around the rod 10 just forwardly of its rear end 15.

Within the rod 10 extends a camera assembly 20 including a camera unit 21, a screened cable 22 and an electrical connector assembly 23. The camera unit 21 is of cylindrical shape and is a close sliding fit within the recess 13, extending close to its forward end. The camera unit 21 includes a conventional camera module and drive and processing circuits. The camera module includes a video camera chip, such as of CCD or CMOS construction and also includes two white light LEDs arranged to direct a beam of light forwardly in the field of view of the camera chip. The camera unit 21 is enclosed within a protective stainless steel can 24 that may be closed at its forward end by a transparent window. The short region 14 at the forward end of the recess 13 provides an annular gap between the outside of the camera can 24 and the inside surface of the recess that is about 0.2mm wide.

The camera unit 21 is sealed within the forward end of the recess 13 by means of an end cap 30 shown in Figure 3, with alternative embodiments shown in Figures 3A, 3B and 3C. The end cap 30 shown in Figure 3 is moulded from a hard plastics material, such as acrylic (PMMA), polycarbonate or polyester compounds, and is of cylindrical shape with an external and internal diameter chosen such that it can be inserted in the enlarged region 14 of the recess 13 between outside of the camera can 24 and the inside wall of the recess. At its forward end, the cap 30 is formed with an external radial rim 31 providing a rearwardly- facing step 32, the external diameter of the rim being matched to that of the rod 10. The rim 31 is rounded at its forward end to provide a smooth outer edge 33. The forward end of the cap 30 also has a shallow internal rim 34 the inside surface 35 of which tapers with a frusto- conical shape having a smaller internal diameter at its forward end than at its rear end. The internal rim 34 also provides a shallow, rearwardly-facing internal step 36 where it meets the inside surface of the cap. The cap 30 has a cylindrical wall 330 extending within the forward end of the rod 10 embracing the forward end of the camera can 24. Its external rim 31 abuts the forward end of the rod 10 to form a smooth, stepless continuation of its external surface and with the smooth outer edge 33 of the cap forming a smooth edge to the tip of the completed assembly of the rod and cap. The cap 30 may be retained in the rod 10 by any conventional means, such as a solvent, adhesive or by bonding or welding. The internal rim 34 is spaced from the forward end of the camera can 24 by a small distance. The cap 30 could be closed by a preformed solid transparent window, such as a plate 38 of glass, bonded into the inside surface 35 of the rim 34. Preferably, however, the cap 30 is sealed by potting the space between the end of the camera unit 21 and the internal rim 34 up to the tapered surface 35 with a transparent material that sets to form a seal between the camera and the cap and to provide a transparent window.

The cap 30 extends rearwardly beyond the camera chip, about two thirds the length of the can 24, but could extend along the entire length of the camera unit can 24 in the recess 13, which would be enlarged appropriately to accommodate this. Such an arrangement could improve the sealing at the forward end of the introducer and also the electrical isolation of the camera unit.

Figure 3 A shows a modified form of cap arrangement where the cap 130 is moulded with an integral window 131 having a groove 132 formed around its inner face 133. The forward end of the camera can 124 extends into and locates in the groove 132. The rear, inside face of window 131 provides a short boss 134 projecting into the forward end of the can 124 with its surface 133 abutting the forward end of the camera module 135. The rear end 136 of the cap 130 extends along about two thirds of the length of the camera unit 121 from its forward end.

Figure 3B shows a cap 130' similar to that in Figure 3A except that its window 13 is thinner and lacks any groove in its rear face 133'. The window 13 l 'is separated from the forward end of the camera module 135' by a small distance, which may be filled with air or by a transparent potting substance. Figure 3C shows a cap 130" identical to that shown in Figure 3B but, in this arrangement, the forward end of the camera can 124" is closed by a transparent cover 125" provided by a disc of clear borosilicate glass about 0.05mm thick with an anti-reflection coating. The cover 125" is sealed within a counterbore 126" at the forward end of the camera can 124". The rear face of the cover 125" abuts the forward end of the camera module 135" and its forward face abuts the rear face of the window 131" of the cap 130".

Instead of using a separate cap to close the forward end of the introducer the forward end of the rod could simply be formed over to provide an internal lip to retain a preformed transparent window disc or a filling of a settable transparent material.

The length of the cable 22 of the camera assembly 20 is such that about 20mm projects from the rear end 15 of the rod 10 when the camera unit 21 is secured in the recess 13. The connector assembly 23 is joined to the rear end of the cable 22 after this has been threaded along the bore 11 of the rod 10. The connector assembly 23 has an elongate axially- extending plug 240 with four metal contact regions 25 to 28 spaced axially and insulated from one another. The innermost contact region 25 is formed with an enlarged metal base flange 29. These contact regions 25 to 28 make electrical connection to a planar contact board (not shown) at the opposite end of the connector assembly 23 to which four individual wires within the cable 22 are bonded, such as by soldering. The contact board is protected within a cylindrical screening cover 230 attached with the connector assembly 23 after the wires have been connected. The external diameter of the cover 230 is the same as the external diameter of the stepped region 16 at the rear end 15 of the rod 10.

With reference now also to Figure 4, the introducer is completed by a sleeve 40 of a rigid plastics material such as acrylic (PMMA), polycarbonate or polyester compounds. The sleeve 40 is about 20mm long with an external diameter matched to the diameter of the rod 10 along the major part of its length and with an internal diameter equal to both the external diameter of the connector cover 30 and to the stepped region 16 at the rear end 15 of the rod. After the connector assembly 23 has been joined to the cable 22 and the completed camera assembly has been tested the sleeve 40 is pushed rearwardly over the connector assembly and onto the rear end 15 of the rod 10 until its forward end abuts the step 17 and its rear end extends along the outside of the cover 30 to overlap the flange 29. Any surplus length of cable 22 is easily accommodated within the sleeve 40 because of its relative large internal diameter compared with that of the rod 10. The sleeve 40 is bonded to the rod 10 and connector assembly 23 in any conventional manner, such as by an adhesive.

The rod 10 could be formed with a Coude tip 50 before or after inserting the camera assembly 20.

The arrangement for forming the rear end of the introducer provides a free length of cable 22 to ensure that there is adequate room to make the electrical connection between the cable and connector 23 after the cable has been threaded along the rod 10 without increasing the overall diameter of the introducer. This facilitates manufacture and keeps expense to a minimum.

Typically, the connector 23 at the rear end of the introducer is connected to a mating connector at one end of a cable extending to a display unit (not shown). The introducer 1 is inserted to the trachea without the endotracheal tube 2 while viewing the display unit. When the tip 12 of the introducer 1 is in the desired location the connector 23 is disconnected from the display unit cable to allow the endotracheal tube 2 to be slid along the introducer from its rear end, over the connector 23. After the endotracheal tube 2 has been slid to the forward end 12 of the introducer 1 the clinician may reconnect the connector 23 to the display unit to confirm that the tube is correctly inserted. Then, the introducer 1 is removed leaving the tube 2 in position. The low profile connector 23 allows the tube 2 to be loaded on the introducer 1 after positioning so that the presence of the tube does not interfere with manipulation of the introducer.