DEVICE FOR PROVIDING AND MAINTAINING BLOODLESSNESS IN LIMB SURGERY

Abstract: A device which is intended to be applied to a limb (3) of a patient in order to provide and maintain a bloodless field in the limb, has a rolling cuff (1) in the form of an annular tube (1) that is made of elastic material. The tube (1) contains pressurised air and is to be rolled onto the limb (3). The tube (1) has a valve member (2) to which a pressure regulating unit can be connected to regulate the air pressure in the tube, the valve member comprising at least two valves (2), which are distributed along the circumference of the cross section of the tube in such a way that at least one valve (2) always is accessible independently of the rolling-on position of the tube (1) on the limb (3). The device further has an expansion lock (4) which is arranged to be mounted round the tube (1) as an enclosing casing when the rolling cuff (1) is applied to the limb (3), thereby preventing the tube from expanding outwards as the air pressure therein increases.

Description: DEVICE FOR PROVIDING AND MAINTAINING BLOQDLESSNESS IN LIMB SURGERY The present invention relates to a device which is intended to be applied to a limb of a patient who is to have an operation in this limb, in order to provide before the operation and maintain during the operation a bloodless field in the limb, and which has a rolling cuff in the form of an annular tube that is made of elastic material and contains pressurised gas, in particular air, and that is to be rolled onto the limb, the tube having a valve means to which a pressure regulating unit can be connected to regulate the gas pressure in the tube. A device of this type is known, for example, from SE 429,714. The known device has a rolling cuff, in which the valve means consists of a valve to which a pump provided with a pressure gauge can be connected in order to inflate the annular tube before it is rolled onto the limb in which the operation is to be carried out. A predetermined air pressure is generated in the tube by means of the pump, which is then disconnected from the valve. The predetermined air pressure, which is in the order of 100 mm Hg, is chosen so that with the selected dimensions of the annular tube, a pressure of about 200-300 mm Hg is exerted on the limb in question. Bloodlessness in the limb is established while the annular tube in the inflated state is rolled onto the limb. The bloodlessness is maintained by retaining the rolling cuff on the limb during the operation. The prior- art rolling cuff has the disadvantage that after being applied to the limb it does not always allow the pump provided with a pressure gauge to be connected to the valve since, depending on the rolling-on position of the tube on the limb, the valve may be completely inaccessible. Thus, it is not always possible to monitor the air pressure in the tube. If the valve, after roll- 2 ing the tube onto the limb, should be accessible for connection of the pump, and consequently it should be possible to read the air pressure in the tube, one would also be able to regulate this air pressure by means of the pump. In the known rolling cuff, it is still not possible to provide a regulation of the pressure, which is exerted on the limb, by regulating the air pressure. A continuous monitoring and regulation of the pressure on the limb is desirable for various reasons, and, in order to enable such monitoring and regulation one often chooses to use the known rolling cuff only for providing bloodlessness and, subsequently, to replace it by a device, for instance, a conventional sphygmomanometer cuff, which allows monitoring and regulation of the pres- sure exerted on the limb, in order to maintain the bloodlessness . The main object of the present invention therefore is to provide a device by means of which bloodlessness can be provided and maintained in a limb and, moreover, which allows monitoring and regulation of the pressure exerted on the limb. According to the invention, this main object is achieved by a device which is of the type stated by way of introduction and is characterised in that the valve means comprises at least two valves, which are distributed along the circumference of the cross-section of the tube in such a way that at least one valve always is accessible independently of the rolling-on position of the tube on the limb, and that the device further has an expansion lock which is arranged to be mounted round the tube as an enclosing casing when the rolling cuff is applied to the limb, thereby preventing the tube from expanding outwards as the gas pressure therein increases. Preferably the expansion lock has a plurality of openings through which the pressure regulating unit can be connected to the valves of the tube. In a preferred embodiment, the expansion lock consists of a strip which is longitudinally non-extensible and which is arranged to be wound round the tube. The strip is conveniently made of a netlike material, such as a nylon net. Preferably the valves are relatively offset in the circumferential direction of the annular tube. In a preferred embodiment, the valve means comprises two valves which are located at an angular distance of about 180° from each other along the circumference of the cross- section of the tube. The known rolling cuff, which is described above, is while in use retained in its position on the limb either by means of one further rolling cuff or by means of one or more wedges. This further rolling cuff and the wedge or wedges take up a relatively large space and may con- stitute an obstacle during the operation. A further object of the present invention therefore is to design the device according to the invention in such manner that the rolling cuff may be fixed in its position on the limb without appreciably reducing the space which is acces- sible for carrying out the operation. This object is achieved by providing the expansion lock with at least one attachment means by means of which it is attachable directly to the limb to keep the underlying tube in place on the limb by frictional contact. In a preferred embodiment, the strip is broader than the annular tube, the attachment means conveniently consisting of Velcro strips or pieces of string or the like, which are attached to the strip. The invention will now be described in more detail with reference to the accompanying drawings, in which: Fig. 1 shows a rolling cuff which is associated with a device according to the invention and which is applied to a limb, Fig. 2 corresponds to Fig. 1 but also shows an expansion lock which is associated with the device and which is applied to the rolling cuff, Fig. 3 shows the expansion lock in a flat state, Fig. 4 is a sectional view of the device along the line IV-IV in Fig. 2 and on a larger scale, and Fig. 5 is a sectional view of the rolling cuff along the line V-V in Fig. 1 and on a larger scale. The device shown in the drawings has a rolling cuff 1 in the form of an annular tube made of rubber material . The tube 1 has two valves 2 which each in prior-art manner consist of a bead, which is integrated with the tube 1 on the inside thereof and has a through hole extending from the inside to the outside of the tube 1. Normally, this hole is sealed as a consequence of the elasticity of the rubber material . Before the rolling cuff 1 is applied to a limb 3 of a patient (human or animal) , who is to have an operation in this limb, a needle-shaped nozzle, which is included in a known pump provided with a pressure gauge, is inserted in the hole in one of the valves 2 , whereupon the tube 1 is inflated to a pressure which is in the order of 100 mm Hg . The rolling cuff 1 is then applied by being rolled onto the limb 3 in the direction indicated by arrow A in Figs 1 and 2 to a position on the limb suitable for carrying out the operation. In order to facilitate the rolling-on and the rolling-off of the rolling cuff 1, the inner walls of the tube are coated with a lubricant, such as silicone oil. During the rolling onto the limb 3, the rolling cuff 1 provides bloodlessness in the limb as it is being rolled on. The bloodlessness is maintained by retaining the rolling cuff 1 on the limb 3 during the operation. Furthermore, the device has an expansion lock 4 in the form of a strip which is longitudinally non-extensible, and which, as is shown in Fig. 2, is broader than the tube 1 and the length of which is greater than the outer circumference of the annular tube. The strip 4 is here made of a netlike material, for example, a nylon net. At each end the strip 4 has four Velcro strips 5a, 5b, 5c and 5d (see Fig. 3) extending in the longitudinal 5 direction of the strip. The two outer Velcro strips 5a and 5d are located at the longitudinal side edges of the strip 4. The Velcro strips 5a-5d at the one end of the strip 4 are attached to the one side of the strip, while the Velcro strips 5a-5d at the other end of the strip 4 are attached to the other side of the strip. Once the tube 1 has been rolled onto the limb 3 and been placed in a suitable position thereon, the strip 4 is arranged round the tube 1 in such manner that one of its longitudinal side edges is placed substantially on a level with the one ring side of the tube 1 (see Fig. 2) , and that the one end of the strip 4 overlaps its other end. The strip 4 is attached round the tube 1 by engaging the Velcro strips 5a and 5b at the one end of the strip with the Velcro strips 5a and 5b at its other end. The strip 4 then forms an enclosing casing which prevents the tube 1 from expanding outwards in connection with a possible increase of the air pressure therein. The strip 4 is attached directly to the limb 3 by engaging the two Velcro strips 5c and 5d at both ends of the strip 4 with one another, the underlying tube 1 being retained in its position on the limb 3 by means of the strip 4 by the strip being attached to the limb and being in frictional contact with the tube 1. Since the strip 4 is attached to the limb 3 on the opposite side of the rolling cuff 1 relative to the side of the rolling cuff 1 where the operation is to be carried out, the means, i.e. the strip 4, used for attachment of the rolling cuff 1 does not reduce the space accessible for the operation. Sometimes it is desirable to displace the rolling cuff 1 somewhat on the limb 3. This may be carried out by disengaging the Velcro strips 5c and 5d at both ends of the strip 4 from each other and by rolling the rolling cuff 1 a short distance in the direction opposite to the arrow A. Owing to the friction, the strip 4 accompanies the rolling cuff 1, which means that in the new position, the strip cannot be attached to the limb 3 by means of the Velcro strips 5c but instead by means of the Velcro strips 5d if the displacement has been moderate. The two valves 2 are located at an angular distance of about 180° from each other along the circumference of the cross-section of the tube (see Fig. 5) . This allows at least one of the valves 2 always to be accessible independently of the rolling-on position of the tube 1 on the limb 3. The valves 2 are relatively offset in the circumferential direction of the annular tube so that they cannot hit one another inside the tube 1 and be damaged in connection with the rolling-on and rolling-off of the tube 1 to and from the limb 3. The strip 4 has openings in the form of meshes . The needle-shaped nozzle of the pump can through such an opening be inserted into the hole in the valve 2 which is accessible when the rolling cuff 1 is applied. Thus, the air pressure in the tube 1 can always be monitored. Moreover, it is possible to regulate the air pressure in the tube 1 in order to regulate the pressure exerted on the limb and, consequently, to adapt it to the patient who is having an operation. The pressure on the limb is usually in the order of 200-300 mm Hg . When an increase of pressure is effected in the tube 1 by means of the pump, also an increase of the pressure on the limb 3 is brought about since the strip 4, which is longitudinally non- extensible, prevents the tube 1 from expanding outwards. The air pressure in the tube 1 can be reduced by letting air out of the tube 1 via a valve associated with the pump. The above described pressure monitoring and pres- sure regulation are carried out manually but it will be appreciated that more sophisticated regulating equipment can be used for automatic pressure monitoring and pressure regulation. The embodiment described above can be modified in many ways within the scope of the invention. Thus, for instance, the rubber material of the tube 1 can be replaced by some other suitable elastic material. The 7 tube 1 can also have more than two valves 2, the valves conveniently being uniformly distributed along the circumference of the cross-section of the tube. Naturally, the strip 4 may have a number of sets of Velcro strips 5a-5d other than four, and the Velcro strips can also be replaced by other suitable attachment means, such as pieces of string or the like.

Claims: CLAIMS 1. A device which is intended to be applied to a limb (3) of a patient who is to have an operation in this limb, in order to provide before the operation and maintain during the operation a bloodless field in the limb, and which has a rolling cuff (1) in the form of an annular tube (1) that is made of elastic material and contains pressurised gas, in particular air, and that is to be rolled onto the limb (3) , the tube (1) having a valve means (2) to which a pressure regulating unit can be connected to regulate the gas pressure in the tube, c h a r a c t e r i s e d in that the valve means comprises at least two valves (2) , which are distributed along the circumference of the cross-section of the tube in such a way that at least one valve (2) always is accessible independently of the rolling-on position of the tube (1) on the limb (3) , and that the device further has an expansion lock (4) which is arranged to be mounted round the tube (1) as an enclosing casing when the rolling cuff (1) is applied to the limb (3) , thereby preventing the tube from expanding outwards as the gas pressure therein increases . 2. A device as claimed in claim 1, c h a r a c t e r i s e d in that the expansion lock (4) has a plurality of openings through which the pressure regulating unit can be connected to the valves (2) of the tube (1) . 3. A device as claimed in claim 1 or 2 , c h a r - a c t e r i s e d in that the expansion lock consists of a strip (4) which is longitudinally non-extensible and which is arranged to be wound round the tube (1) . 4. A device as claimed in claim 3, c h a r a c t e r i s e d in that the strip (4) is made of a netlike material, such as a nylon net. 5. A device as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that the valves (2) 9 are relatively offset in the circumferential direction of the annular tube. 6. A device as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that the valve means comprises two valves (2) which are located at an angular distance of about 180° from each other along the circumference of the cross-section of the tube. 7. A device as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that the expansion lock (4) has at least one attachment means (5a-5d) , by means of which it is attachable directly to the limb (3) to keep the underlying tube (1) in place on the limb by frictional contact. 8. A device as claimed in any one of claims 3-4 in combination with claim 7, c h a r a c t e r i s e d in that the strip (4) is broader than the annular tube (1), and that the attachment means consists of Velcro strips (5a-5d) , which are attached to the strip (4) . 9. A device as claimed in any one of claims 3-4 in combination with claim 7, c h a r a c t e r i s e d in that the strip (4) is broader than the annular tube (1) , and that the attachment means consists of pieces of string or the like, which are attached to the strip (4) .

Inventors: BLOMBERG BJOERN, BLOMBERG, BJOERN
Applicants: BLOMBERG BJOERN, POMIDOR AB, BLOMBERG, BJOERN
Application year: 1999
Main classification: A61B17
IPC codes: A61B5, A61B17