MEDICAL SYRINGE

Abstract: A device for use in surgical procedures formed of a concertina cartridge (1) of a resilient plastics material. The cartridge (1) has a nozzle (5), the throat of which is designed to receive by snap-click action, a projection (9) formed internally of the chamber (1), to hold the cartridge in a collapsed, but resiliently releasable, state as it is compressed to that state under concertina action. The device has applicability to surgical procedures such as blood collection, drug infusion, and balloon catheter inflation while eliminating the dangers of bacterial infection always present when performing such procedures using devices and systems of the prior art.

Description: MEDICAL SYRINGE FIELD OF THE INVENTION The present invention relates to a device for use in surgical, medical and therapeutic procedures. BACKGROUND ART It is common practice for plastics or rubber tubes to be inserted into the tissues, cavities, orifices or veins of the human body. Such tubes (otherwise known as catheters or cannulae) possess two channels down the central bore of the catheter. Whilst one (the larger) channel, is used for the infusion of fluid into or drainage out of the body, the other smaller diameter channel communicates with a latex balloon placed concentrically around the catheter shaft and close to the end of the tube which is left within a body cavity, e.g. the urinary bladder. The other end of the smaller channel is protected by a plastic hub containing a displaceable rubber diaphragm which acts as a one¬ way valve. This secondary channel and valved-port permits the inflation of the balloon which then effectively engages upon the surrounding tissues of the body cavity and prevents the catheter from sliding out of the body. The technique and procedure for inflating the balloon at the present time, involves a series of actions on the part of a nurse or doctor, including the manipulation and breaking open of an ampoule or bottle or sterile water or saline; the opening of a sterile packet containing an hypodermic type plastics syringe; the opening and use of a sterile needle or plastics quill from a packet to aspirate the contents of the ampoule into the syringe; and finally the insertion of the nozzle of the full hypodermic into the valved-inflation port of the catheter. Moreover the resistance of the valve diaphragm must be overcome and a precise volume of fluid discharged into the balloon to achieve inflation, before the hypodermic syringe is removed from the inflation port. It can be easily seen from the above that numerous components are required to perform the task and the risk of bacterial contamin¬ ation during the various stages is an ever present potential problem. Similarly, another common and important function of plastics tubes which have been partially inserted into the body is their use as a portal for access to the venous or arterial system. In these circumstances, a short length of fine-calibre hollow plastics or rubber tubing is placed, by a variety of techniques, into the lumen or channel of a blood vessel through a small wound in the skin. The central channel of the hollow catheter thereby is able to conduct a variety of physiological fluids Into the blood vascular system. The ends of the cannulae external to the body surface are fitted with a plastics or metal female luer hub which conforms to an Inter¬ national Standard in respect of its internal configuration. Into this female luer hub, can be fitted a male luer nozzle which also conforms to an International Standard specification. The normal practice is for the male nozzle to be the end componen of an infusion tubing system which slowly delivers fluid from an intravenous bottle or bag, under the influence of gravity or a mechan¬ ical roller-pump. At intervals, in the care of patients, the need for the infusion system can be dispensed with, in order to make the patients more mobile and allow them to walk freely about the wards and corridors. To achieve this end, the female hub of the intravenous cannula is covered by a small plastics cap or plug. However, before this is performed, the cannula tubing must be filled with a saline solution (often containing an anticoagulant agent -- heparin) to prevent coa¬ gulation of the blood within the cannula and adjacent blood vessels. This procedure, as in the case of the catheter balloon inflation manoeuvre, also requires the same range of accessory equipment to be used as previously described in the preceding paragraphs, to accomplish the final objective. SUMMARY OF THE INVENTION It is an object of the invention to provide a device for use in surgical procedures which can simultaneously perform all the necessary functions required for the inflation of medical catheter balloons and the aseptic occlusion of the hubs of vascular cannulae and avoiding the problems and complexities as above described. It is a further object of the invention to provide a device for use in surgical procedures such as drug infusion and blood collection which avoids the problems of bacterial infection and, in the case of blood collection, also the accidental injection of air into the patient According to the invention there is provided a device for use in surgical procedures comprising a cartridge, a nozzle on the cart¬ ridge adapted for connection to a medical catheter and/or tube, the walls of said cartridge being designed to allow the cartridge to be depressed by concertina action from an expanded state to a collapsed state to expel its contents through said nozzle, and means in the cartridge arranged to be interengageable with said nozzle as the cart¬ ridge moves to said collapsed state thereby to hold the cartridge in that state and close the nozzle. With this device so defined it is possible simultaneously to inflate medical catheter balloons and occlude the hubs of vascular cannulae which previously required a variety of complicated procedures and accessory equipment not consonant with the achievement of the desired objective of avoidance of bacterial contamination and enhance¬ ment of efficiency and high standards of patient care. It is also possible to employ the device to perform infusion of drugs, as a blood or body fluid collection device. A good measure of the range of the objectives and advantages of the invention will be apparent from the following disclosure directed to more specific details of some examples whereby the invention may be put into practical effect. BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS Some embodiments of the invention will therefore be described hereinafter by way of example with reference to the accompanying drawings wherein; Figure 1 is a sectional view of a device for use in surgical procedures; Figure 2 shows the device of Figure 1 moved from its expanded state as shown in that Figure, to a collapsed locked position; Figure 3 is a modified form of the device shown in Figure 1; Figure 4 illustrates in perspective view, a further modification of the device for use in surgical procedures shown in either Figure 1 or Figure 3; Figure 5 is a perspective view of the device according to the invention modified for use in the administration of drugs; and Figure 6 illustrates how a bank of drug infusion devices may be assembled together for a multiple drug infusion procedure employing a syringe infusion pump. BEST MODES OF CARRYING OUT THE INVENTION The device for use in surgical procedures shown in the drawings comprises a main hollow cartridge chamber 1, the walls 2 of which are designed, either in circular, oval or rectangular cross-section, for concertina action between an expanded state, shown in Figures 1 and 3, and a collapsed state, as shown in Figure 2. The cartridge chamber 1 and its various component parts to be described, will normally be manufactured in a flexible plastics materia using blow-mould technology to achieve the precise shapes required. One end wall 3 of the cartridge chamber 1 has a centrally posi¬ tioned integrally formed male luer cone shaped nozzle 4 which fits precisely current balloon inflation ports on medical catheters and vascular cannula female luer hubs (not shown) . The internal bore of the nozzle 4 has a depressed peripheral region 5 which forms a dilatation 6 near the throat of the nozzle 4 in conjunction with a constriction 7 between the dilatation 6 and the end wall 3 of the cartridge chamber 1. Centrally positioned on the internal surface of the other end wall 8 of the cartridge chamber 1, is a projecting peg or stud 9 in axial alignment with the axis of the nozzle 4. The stud 9 has a rounded head 10 the largest diametrial portion 11 of which is equal to the diameter of the dilatation 6 in the nozzle 4. The neck of the stud 9 tapers from a smallest diameter 12, equal to or less than the diameter of the constriction 7 in the nozzle 4, to a largest diameter 14 at its base 15 adjoining the end wall 8 of the cartridge chamber 1. -6- The outer surface of the end wall 8 of the cartridge chamber 1, see Figure 3, is recessed at 16 conveniently to receive an oper¬ ator's thumb. Similarly the outer surface of the end wall 3, each side of the nozzle 4, is recessed at 17 to accommodate the tips of two fingers of the operator, and by the combination of the recesses 16 and 17 the operator is able to apply a safe and controlled continuous pressure when using the device as will be explained. Thus operated with one hand, the device acts as a small totally- closed pump, whereby pressure applied to the end wall 8 by the thumb towards the other end wall 3 controlled by the tips of two fingers of the same hand, expells the cartridge contents be it air or liquid. Thus with liquid in the cartridge chamber 1 depression of the cartridge in the way described will qause the liquid to be ejected via the nozzle 4 through a medical catheter balloon inflation valve port or into an intravascular catheter. Once the injection is completed in this way, the head 10 of the stud 9 will positively engage the throat of the nozzle 4 as by a snap-fit action as the portion 11 engages the dilatation 6 behind the constriction 7 with a pronounced click. The closing action will effectively prevent the reflux of any of the contained fluid or body fluid back into the chamber 1. Due to the resiliency of the component parts of the device as described, release of the stud 9 from engagement with the throat of the nozzle 4 may be effected by simple finger pressure as will be appre- caited. This facility provides an effective hydraulic sealing cap for intravascular devices and prevents re-use and therefore bacterial contamination of the concertina cartridge. Because fluid contained in the chamber 1 is totally enclosed as it is ejected, the potential for bacterial contamination is also removed during this injection phase, in contrast to a conventional syringe barrel which has a small but definite space around the plunger allowing leakage, air entry and the entry of micro-organisms. In a modified form of the device, means may be provided, as shown in Figure 3, to assist retention of the device in its collapsed state as shown in Figure 1. This assistive means comprises the pro¬ vision of resilient flanges F on the end wall 8 of the chamber 1 carrying catches C. The other end wall 3 of the chamber 1 would then have comple- mentary formations as at H to engage the catches C in the collapsed state. A further modification of the device according to the invention not shown in the drawings may employ the use of a bayonet catch formed on the stud 9, the internal bore of nozzle 3 being suitably adapted to engage the bayonet catch in the collapsed state. The device as described with reference to Figures 1 and 3 may be used as a syringe cartridge for the infusion of solutions of drugs of a wide variety of volumns at controlled rates by non-manual com¬ pression using non-mechanical or electrical infusion pumps. in this application the precise flow rate of dispensed fluid is_ critical and therefore to prevent distortion of the concertina walls of the chamber 1, these walls may be provided with suitably positioned indents I as shown in the modification of Figure 4, into which are located stiffening rods R which act as guide elements as the cartridge chamber is compressed. In this application the syringe cartridge will be linked through the nozzle 4 by a short piece of flexible plastics tubing to a cannula or catheter (not shown) inserted into the body of a patient or animal. By using such a system the need for complex plastics administration sets which rely upon gravity for the force of administration would be eliminated. This would be of particular value in patients requiring evacuation from accidents by air, sea or road transport. Current hypodermic syringes consist of a barrel and a separate plunger thus allowing the potential or bacterial entrance into the syringe chamber. It will be appreciated that the device of the invention avoids this hazard. For multiple drug infusion applications each cartridge chamber, as shown in Figure 5, may be provided with means 18, see Figure 5, engageable with a drive shaft 19 of a mechanical or electrical infusion pump (not shown). As shown at 18 in Figure 5, the engagement means in a representa¬ tive cartridge may take one of several forms, for example, square, circular, ttriangular or crossed shaped recesses. In this case the drive shaft 19 shown in Figure 5, of the infusion pump would be provided with end pieces 20 shaped for reception within the recesses 18 as appropriate. The particular shaped recess in a representative drug infusion cartridge would then act as an identification of the drug in that cart- ridge so that a whole bank of cartridges 1 could be mounted to an appropriately designed and coded infusion pump., shown schematically as 20 in Figure 6, and operated by micro-processor means (not shown) on a totally automatic, non-manual and precisely controlled basis. The invention may also be used in another form as a blood or body fluid collection device. In this application the closure mechanism is illustrated in Figures 1, 2 and 3 allows the device to be delivered to the patients in a collapsed state and thus empty of any air. In this way the danger of accidental injection into the patient is avoided. For this application, the rearward end of the cartridge may be extended as a flange (not shown) for gripping between finger and thumb during the blood collection procedure. In another form the device can be used to instill antiseptic solutions through the tap mechanisms of plastics urinary drainage collection bags. This effectively provides an antiseptic locking mechanism and prevents bacterial entry into the sterile urinary drainage system. Other modifications will be readily apparent to one skilled in the art but such will fall within the scope of the inventions defined in the following claims.

Claims: CLAIMS 1. A device for use in surgical procedures comprising a cartridge chamber, a nozzle on the cartridge chamber adapted for connection to a medical catheter and/or tube, the walls of said cartridge chamber being designed to allow the chamber to be depressed by concertina action from an expanded state to a collapsed state to expel its contents through said nozzle, and means in the cartridge arranged to be interengageable with said nozzle as the cartridge moves to said collapsed state there- by tohold the cartridge in that state and close the nozzle. 2. A device as claimed in claim 1 wherein said means in the cartridge comprises a shaped projection on that inner wall of the cartridge farthest from the throat of said nozzle, said throat being resilient and internally shaped to complement said shaped projection, in at least one aspect, so enabling snap-fit engagement therewith. 3. A device as claimed in claim 2 Wherein said shaped projection has a peripheral recess which engages a constriction complementary thereto in the throat of said nozzle so providing said snap-fit engagement. r 4. A device as claimed in claim 3 wherein that end wall of said cartridge chamber carrying the shaped projection is provided with exteriorly formed resilient projections which engage complementary formations on the exterior of said other end wall of the chamber in the collapsed state of the cartridge chamber. 5. A device as claimed in any preceding claim wherein the outer concertina wall edges of the cartridge chamber are provided with indents carrying stiffening rods which form guide elements for the cartridge chamber during movement between said expanded and collapsed state. 6. A device as claimed in any preceding claim formed wholly of a plastics resilient material. 7. A device as claimed in any preceeding claim wherein the end of the cartridge chamber opposite the nozzle is provided with a recess, said recess being shaped to receive a complementary shaped end piece of the drive shaft of a syringe infusion pump to enable automatic controlled depression of the cartridge chamber thereby. 8. A device as claimed in claim 7 wherein said recess is of variable cross-section from cartridge to cartridge so providing identi- fication means for a drug compound within the cartridge. 9. A device for use in surgical procedures substantially as here¬ inbefore described with reference to and as illustrated in the accompanying drawings.

Inventors: PETERS JOSEPH LENNOX, PETERS, JOSEPH, LENNOX
Applicants: CLINICAL PRODUCT DEV LTD, CLINIMED LTD, CLINICAL PRODUCT DEVELOPMENT LTD., CLINIMED LIMITED
Application year: 1986
Main classification: A61M3
IPC codes: A61B5, A61M3, A61M5