Title MEDICAL INSTRUMENT BAG 5 Field The present invention relates to bags for containing and transporting medical instruments, typically but not exclusively sterilised instruments supplied and 10 transported to a hospital. Background to the Invention In large hospitals, sterilization of surgical instruments 15 is usually carried out by a specialised service that may operate off site to sterilize instruments and return them to the hospital in labelled hermetically sealed disposable bags. 20 Conventional disposable bags used for this purpose comprise a first side and a second side heat sealed at any open edges so as to encompass the medical item. The first side may be composed of paper, on which is printed identifying and tracking information, and the second side 25 may be a layer of polyethylene. Alternatively the fisrt and second sides may both be composed of a layer of polyethylene. A problem with the existing bags is that there is a 30 tendency for the bags to be punctured in handling from the sharp edges of the instruments, particularly in the case of bags containing several instruments. This is important particularly where maintenance of sterility is concerned. 35 There is therefore a need for a practical disposable bag for medical instruments that overcomes this problem.
- 2 Summary of the Invention According to a broad aspect of the invention there is provided a disposable bag containing at least one medical 5 instrument, comprising a first side and a second side heat sealed together near otherwise open edges so as to encompass and contain the medical instrument, wherein the first and second sides are composed of a laminated material comprising a layer of a polyamide material 10 laminated to a layer of polyethylene. In one embodiment, the first and second sides are formed by separate sheets of the laminated material. 15 In another embodiment, the first and second sides are formed by a single sheet of the laminated material folded over to form a closed edge. In one embodiment, the first and second sides are heat 20 sealed near an entry edge of the otherwise open edges so as to allow opening the bag by gripping the first and second sides along the entry edge and pulling apart so as to break the seal near the entry edge. The heat seal near the entry edge may break at a lower pulling force than the 25 heat seal near at least one of the other otherwise open edges. In one embodiment, the polyamide material is a nylon fabric. 30 In one embodiment, a total thickness of the laminated material is between 0.05mm and 1 mm. In one embodiment, a ratio of the thickness of the layer 35 of polyethylene to the thickness of the nylon layer is between 99:1 and 1:99.
- 3 Brief Description of Drawings Figure 1 shows a bag containing a medical instrument in 5 accordance with a first embodiment of the current invention; Figure 2 shows a bag in accordance with a second embodiment of the current invention, before insertion of 10 a medical instrument and final sealing along one edge. Detailed Description of embodiments 15 Embodiments of the current invention will now be described. Referring to Figure 1, bag 1 contains a medical instrument 20 2. Bag 1 is composed of a single sheet of laminated material folded to form a closed edge 3 and first and second sides, heat sealed along or near otherwise open edges 4, 5 and 6, as represented by the regions bounded by dotted lines. 25 The laminated material has a total thickness of approximately 0.1mm and is composed of a layer of a nylon fabric polyamide material laminated to a layer of polyethylene. A ratio of the thickness of the layer of 30 polyethylene to the thickness of the nylon layer is about 9:1. The lamination is performed according to standard lamination techniques used in the plastics industry. In this embodiment the bag is formed so the layer of nylon 35 faces outside, but in other embodiments either orientation for either side is acceptable. The heat seals along edges 4 and 5 are effected by heat - 4 alone applied at a sufficient temperature and duration to fuse the two juxtaposed layers of polyethylene, so as to provide a strong seal. The heat seal 7 near entry edge 6 is effected by the use of a thermoplastic glue known as 5 "medical glue" so as to provide a less strong seal, to allow opening of the bag by gripping the first and second sides that form lips along entry edge 6 and pulling apart so as to break seal 7 and separate the first and second sides at entry edge 6. The width of the seal 7 is usually 10 between 5mm and 20mm, more typically 10mm to 15mm, depending on the size of the bag contents, to allow the right balance of seal strength and opening ease. This is a matter of trial and error and as will be appreciated depends also on the particular thermoplastic glue chosen, 15 of which several may be suitable. The bag is labelled by a printed adhesive label on either side. 20 Referring now to Figure 2, a second embodiment before insertion of a medical instrument is shown, composed of separate sheets of the laminated material oriented as before with the nylon layer facing outwards. Medical glue is used to form a peelable heat seal, shown as black 25 regions, near three edges 40, 50 and 60. Entry edge 60 has two corner areas 71 and 72 sealed with medical glue to protect angle-shaped heat seal 70 from accidental breach during transport. Edge 30 is left open until a medical instrument is inserted, and is then heat sealed to form a 30 strong seal by heating sufficiently to fuse the two juxtaposed polyethylene layers together as described above. When the two sheets at entry edge 60 are gripped and pulled apart in the centre, the angle shape of heat seal 70 facilitates peeling apart of the two sides, 35 beginning at the centre and moving down both sides 4 and 50. Persons skilled in the art will also appreciate that many - 5 variations may be made to the invention without departing from the scope of the invention. For example, the heat seals near the otherwise open edges 5 do not need to be linear and none, some or all of the heat seals near different edges may use a glue to facilitate easy entry as described above, or not. Further, any ratio of thickness of the two layers mentioned so as to provide a bag of superior strength compared to existing bags is 10 contemplated. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary 15 implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. 20 It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any 25 other country.