NEEDLE FOR A SYRINGE, SYRINGE AND CORRESPONDING CONTROL SYSTEM

Abstract

It is disclosed a needle (1) for a syringe, including a tip (2) at one end (3) of the needle, adapted to penetrate a body tissue during usage of the syringe, and a hub (4) at the other end (5) of the needle, to attach the needle to the syringe. A pressure sensor (6) is in the needle; means (7) are provided to transmit outside the needle a pressure value sensed by the pressure sensor (6) in the needle.

Claims

1-27. (canceled)

28. Needle (1) for a syringe, including: a tip (2) at one end (3) of the needle, adapted to penetrate a body tissue during usage of the syringe; a hub (4) at the other end (5) of the needle, to attach the needle to a tube or to the syringe; including: a pressure sensor (6) in the needle; means (7) to transmit outside the needle a pressure value sensed by the pressure sensor (6) in the needle, characterized by the fact that said means (7) are fixed inside the hub (4) and include a cable, the cable comprising a first end (7a) optically or electrically connected to the pressure sensor (6) in the needle, a second end (7c) which exit from the needle through said other end (5) of the needle, and a portion (7b) between the first end (7a) and the second end (7c) inside the needle, wherein the pressure sensor is not fixed to the shaft of the needle and wherein the first end (7a) of the cable is attached to the pressure sensor (6) and the cable avoid fluctuation of the pressure sensor (6) in the needle.

29. Needle according to claim 28 wherein the pressure sensor (6) is at the tip (2) of the needle or at a predetermined distance (d) from the tip or from a bevel of the needle, said predetermined distance from the tip or bevel being from 1% to 20% of a length of the needle.

30. Needle according to claim 28 wherein the pressure sensor (6) is at the second end (5) of the needle or at a predetermined distance from the second end (5), said predetermined distance from the second end (5) being from 1% to 20% of a length of the needle.

31. Needle according to claim 28 wherein the sensor includes a sensing surface (6a) arranged to be contacted by a fluid to be injected with the syringe, and being adapted to measure a pressure of the fluid around the bevel, and/or a variation of the fluid pressure around the bevel.

32. Needle according to claim 31 wherein the sensing surface includes at least a portion perpendicular to an axis of the needle, said portion being towards the tip of the needle.

33. Needle according to claim 28, including means (40) for protecting the sensor in the needle, the protection means (40) being arranged between the tip (2) of the needle and the sensor (6).

34. Needle according to claim 28, wherein the cable is fixed to the hub (4) at a position (P) of the cable leaving a predetermined length (L) of the cable inside the needle, said predetermined length substantially corresponding to a predetermined distance of the pressure sensor (6) from the second end (5) of the needle.

35. Needle according to claim 34, wherein the second end of the cable (7c) includes a wireless interface (9) to transmit wirelessly the pressure value to a device outside the needle.

36. Needle according to claim 28, wherein the cable is an optical fibre.

37. Needle according to claim 36, wherein the pressure sensor (6) is a Fabry-Perot optical fibre sensor.

38. A system including a device connected or connectable to the means (7) of the needle according to claim 28, to control the pressure in the needle.

39. System of claim 38, wherein said second end of the cable is connected to the device and the pressure sensor is powered by the device.

40. System according to claim 38, wherein the device includes an alarm system configured to emit an acoustic and/or audio and/or video signal when the pressure value is above or below a predetermined threshold.

41. System according to claim 38, wherein the device includes a user interface to display the pressure values and/or pressure curve in real-time.

42. System according to claim 38, wherein the device includes a wireless interface adapted to be connected to a portable device or to a PC to transmit at least said pressure values.

43. System according to claim 38, wherein the device stores a plurality of pressure values detected by the sensor during an injection at corresponding injection times, and means to build a profile of pressures associated to the injection, the profile being representable as a curve on a display.

44. System according to claim 38, further including nerves stimulation means to stimulate nerves for an optimal positioning of the tip of needle.

45. System according to claim 44, wherein an electrode of the nerves stimulation means is the needle, and said electrode is electrically connected to a generator of electrical pulses to deliver said pulses to the nerves.

46. System according to claim 45, wherein the generator is included in said device.

47. System according to claim 38 further including a syringe adapted to be connected or connected to said needle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0085] FIG. 1 schematically represents a needle according to the prior art.

[0086] FIG. 2 schematically represents a needle according to the present invention.

[0087] FIG. 3 is an enlarged cross section of portion A of the needle of FIG. 2.

[0088] FIG. 4 is the portion of the needle of figure A, according to a first embodiment of the present invention.

[0089] FIG. 4 is the portion of the needle of figure A, according to a second embodiment of the present invention.

[0090] FIG. 5 is the portion of the needle of figure A, according to a third embodiment of the present invention.

[0091] FIG. 6 is the portion of the needle of figure A, according to a fourth embodiment of the present invention.

[0092] FIG. 7 is the portion of the needle of figure A, according to a fifth embodiment of the present invention.

[0093] FIG. 8 is the portion of the needle of figure A, according to a sixth embodiment of the present invention.

[0094] FIG. 9 id the portion of the needle of figure A, according to a seventh embodiment of the present invention.

[0095] FIG. 10 is the portion of the needle of figure A, during use.

[0096] FIG. 11 is the needle of figure A, according to an embodiment of the present invention.

[0097] FIG. 12 is a diagram representing the pressure drop in the needle as a function of the infusion rates and for different needle dimensions (internal diameter and length).

DETAILED DESCRIPTION

[0098] With reference to the annexed drawings, it is hereafter disclosed and indicated with reference number 1 a needle according to the present invention, and more particularly a needle adapted to be plugged to a tube and/or to a syringe including a liquid, the liquid being directed to be injected in the body of a patient for a predetermined application. Just as example and without limiting the scope of protection of the invention, the application may be an anaesthesia and the liquid may be a local anaesthetic; in such application, it is important to avoid that the liquid is not injected in a nerve.

[0099] According to the present invention, the needle 1 has a tip 2 at one end 3, a hub 4 at the other end 5, as schematically represented in FIG. 2. FIG. 3, is an enlarged cross section of a portions A of FIG. 1, representing a sensor 6 inside the needle. The sensor is in the needle shaft. Preferably, the sensor is at the tip portion 2 of the needle.

[0100] During use, the needle passage through body tissues, as represented in FIG. 10; in this figure the needle has passed through the epidermises and the tip 2 of the needle is inside a nerve, where the anaesthetic liquid should not be injected. The nerve makes resistance to the liquid injected which is greater than a resistance exerted on the liquid from other tissues or body fluids, for instance the pressure exerted by a muscle.

[0101] According to the invention, when the syringe is actuated, i.e. when the plunger is pressed, the liquid pass from the liquid container in the syringe into the needle shaft, wherein the pressure sensor detect the pressure of the liquid. The pressure value detected by the sensor is compared to a threshold value which is associated to the kind of injection, i.e. to the kind of application. For instance, the threshold for the application anaesthesia is set to a value X which is less than the pressure exerted by a nerve into which it is to be avoided the injection of the anaesthetic liquid.

[0102] With reference to FIG. 3, the threshold is stored inside the pressure sensor 6, the same being also provided with an alarm system, adapted to emit an acoustic signal, when the threshold is reached. The sensor is fixed inside the needle shaft, for instance in a thickness of the needle (not represented). The threshold may be pre-set and not changeable or it may be re-written in a read-write memory of the sensor.

[0103] According to the present invention, means 7 adapted to transmit outside the needle a pressure value sensed by the pressure sensor 6 in the needle.

[0104] FIG. 4 schematically represents an embodiment of the means 7, wherein the means 7 includes a wireless interface to transmit wirelessly the pressure value to a device outside the needle (not represented). More particularly, the means 7 and the pressure sensor 6 may be embedded on a same board 8. The board 8 may be fixed inside the needle, for instance in the thickness of an internal wall of the needle shaft or on the internal wall.

[0105] With reference to FIG. 5 and to another embodiment of the invention, the means 7 and the pressure sensor 6 are on separate boards 8a, 8b, and the separate boards are connected together, inside the needle, for instance through a wired connection. The separate boards 8a, 8b are also connected to the needle, for instance on the internal wall or in the thickness thereof.

[0106] According to a preferred embodiment of the invention, the sensor 6 is connected by wire, (rigid or semi rigid according to different aspects of the invention) to an external device, as represented in FIG. 6. In this case, the means 7 includes a cable, the cable comprising a first end 7a optically or electrically connected to the pressure sensor 6 in the needle, a second end 7c which exit from the needle through the other end 5 of the needle, and a portion 7b between the first end 7a and the second end 7c inside the needle. The cable may be an optical fibre.

[0107] Nothing prevents that the second end of the cable 7c includes a wireless interface 9 (FIG. 7) to transmit wirelessly the pressure value to a device outside the needle, instead of being wired connected to the external device. This solution is advantageous because the wireless interface is outside the needle, i.e. does not reduce the space in the free needle, and does not required a wired connection to external device, which is preferred for free movements of the user during injection.

[0108] The cable may be fixed to the hub 4 at a position P of the cable leaving a predetermined length L of the cable inside the needle, predetermined length substantially corresponding to a predetermined distance of the pressure sensor 6 from the second end 5 of the needle, for instance as represented in FIG. 7.

[0109] The same apply to the embodiment of FIG. 6. In these embodiments, the sensor is at a predetermined distance d from the tip or from the bevel of the needle. Preferably, the predetermined distance from the tip or bevel is from 1% to 20% of a length of the needle.

[0110] As specified above, the rigidity of the cable is chosen depending on the embodiment of the needle, for instance, for the embodiment schematically represented in FIG. 6, wherein the sensor is maintained in a floating position inside the needle shaft by the cable, it is appropriate that the cable is rigid, so as to avoid fluctuation of the sensor during liquid injections, and corresponding pressures variations and errors in said detections. In FIG. 6, the cable is represented as partially curved but nothing prevents that it is at the end of a riding and rectilinear cable.

[0111] With reference to FIG. 8 and to another embodiment, the pressure sensor 6 is at the second end 5 of the needle or at a predetermined distance from the second end 5, the predetermined distance from the second end 5 being from 1% to 20% of a length of the needle. In one embodiment the pressure sensor 6 is in the hub, as schematically represented in FIG. 9. Such embodiments are preferred when high pressures are involved, since in such applications, the sensor 6 may easily detect the pressure also at a distance from the tip substantially corresponding to the length of the shaft but at the same time it is more protected inside the needle, for instance from contacts with body tissues, since more retracted in the needle and distant from the bevel.

[0112] In a preferred embodiment of the invention, the cable is an optical fibre connected at one end with the sensor and at another end with an external device, and the sensor is powered by the external device. The external device may be a personal computer or a smartphone or a portable device including means to set and store a threshold in a memory, means to receive a pressure value through the optical cable from the sensor. Said means of the external device further include a comparator to compare the threshold with the pressure value and an alarm system, to alert the user when the pressure value is above or below the threshold, depending on the application.

[0113] In FIG. 11, another embodiment of the present invention is schematically represented, wherein means 40 for protecting the sensor are provided within the needle, for instance a protection grid 40 or a mesh 40 inside the shaft, between the tip 2 and the sensor 6. The protections grid 40 protects the sensor inside the needle, especially during the insertion of the needle in the body tissues, when tissues may enter the needle.

[0114] FIG. 12 is a diagram schematically representing the pressure drop in the needle as a function of the infusion rate, in connection with four different needles distinguished from their diameter and lengths. Advantageously, according to the present invention, the pressure measured by the sensor at the tip of the needle is the real pressure of the liquid at the tip, which is substantially equal to the pressure of the nearby body portion in which the liquid is injected, and therefore gives precise information on such body portion, being any body portion characterized by a corresponding pressure.

[0115] To the contrary, according to the device of the prior art, the pressure measures in a casing arranged between the syringe and the needle is different from the real pressure at the tip, due to pressure drops which, among other factors, depends on the needle size and injection rates, as schematically represented in FIG. 12.

[0116] Still according to the present invention, a method to control the injection of a liquid through a needle is disclosed. The method comprises the steps of penetrating a body tissue with a needle having a tip 2 at one of its end and a hub 4 at the other end 5, the hub attaching the needle to a tube or to a directly syringe used to execute the injection. Once the needle has been positioned into the anatomical region wherein the injection should be made, the operator begins to inject the drug through the syringe.

[0117] A pressure sensor 6 in the needle, preferably in the tip 2 of the needle, measures the pressure of the liquid in the needle and means 7 transmit the pressure value outside the needle. The pressure value is compared with a pressure threshold, which is previously set, based on the type of injection which is performed, and therefore on the base of the anatomical region wherein the injection should be made. If the pressure value is not compatible with the pressure threshold, an alarm is emitted and the operator may immediately stop injecting.

[0118] For instance, if the type of the injection is in the setting of regional anesthesia, the liquid (i.e. the local anesthetic) should be injected near the nerve to be blocked but not in the nerve itself. Therefore, the pressure threshold is the typical pressure near the nerve, which is lower than the typical pressure inside the nerve. During injection, if the sensor detects at the tip of the needle a pressure greater than the pressure threshold, the alarm is emitted. Moreover, in order to avoid the backtrack of local anesthetic to the epidural space (in case of injection close to the vertebral column), the exceeding of a pre-set pressure threshold also lead to an alarm emission by the system.

[0119] Advantageously, the system of the present invention, further than a controlling pressure threshold adapted for the injections, is also adapted to collect pressure profiles associated to the injections. More particularly, the external device connected to the sensor in the needle stores a plurality of pressure values detected by the sensor during an injection at corresponding injection times, and includes means to build a profile of pressures associated to the injection, the profile being representable as a curve on a display. The means to build the profile of pressures includes for instance a software application for PC or an application for apps and the display may be a monitor of a medical device, a pc or a portable device, such as an iPhone, iPad or tablet.

[0120] The external device stores a plurality of profiles of pressures associated to a corresponding plurality of injections. Injections made by a same operator may be grouped.

[0121] The external device, for instance the above mentioned software application, may include a user interface adapted to associate a user's score to a profile of pressures, the score being dependent on the result of the injection made by the user. For example, an anaesthesiologist, based on its feeling or the reaction of the patient or his personal feed-back or medical examinations, may type the user interface and set the score. Preferably in the same user interface and in association to the injection performed, the user sets a field associated to the kind of injection, For instance, the anaesthesiologist may set the field to anaesthesia for all his injection; in one embodiment, the field is automatically set for the user, based on the kind of injections he makes.

[0122] In the particular case of peripheral nerve blocks, the fine, accurate and precise real-time measurement of the injection pressures at the needle tip can help reshaping the practice of regional anesthesia. A combination of information related to the motor response to nerve stimulation and the injection pressure can not only help the operator to avoid complication related to a intraneural injection but also help him to optimize the needle tip positioning, in order to maximizing efficacy of the nerve block while preserving safety, through a sub-perineural but extra-epineural injection of local anesthetic. Perineurium is the sheath encapsulating the nerve to protect it and constitute a natural barrier to the spread of the local anesthetic, thus slowing its onset and potentially jeopardizing its clinical outcome. Epineurium instead is the relatively anelastic inner sheath which delimitates the nerve and shell not be penetrated by the needle tip in order to avoid increase of intraneural pressure following the injection of local anesthetic, potentially leading to an ischemic damage due to the collapse of vasa-nervorum. The ideal spot to inject the local anesthetic would be the space between the perineurium and the epineurium: this would optimize the clinical effect of the block, trespassing the barrier to the local anesthetic spread represented by the perineurium, minimizing the necessary total volume and significantly reducing the onset time.

[0123] Ultrasound guided regional anesthesia has become a widely accepted standard in contemporary clinical practice. Real-time ultrasound guidance consent to visualize the needle and the target structure, visualizing eventual obstacles on the path (such as vessels, the pleura, organs, etc.). However echography is operator-dependant and the resulting image quality is heavily affected by many variables affecting the acoustic windows (such as structures depth, the angle between the needle and the ultrasound bean axe, anisotropy of nerves). The needle tip position is thus often difficult to visualize with a reasonable degree of confidence and this translates into many reports of accidental intraneural injections and nerve lesions under ultrasound guidance.

[0124] Moreover the definition actually provided by ultrasound machines is not sufficient to discriminate millimetric spaces and structures, such as the perineural and epineural sheaths and the space in between them.

[0125] With these premises, the electrophysiologic information provided by the nerve-stimulator, together with a precise information about the injection pressure at the needle tip, are usefully complementing the ultrasound image to provide a broader picture. A minimal electric threshold to elicit electric response (<0.2 mA) is helpful to exclude a subepineural placement of the needle tip; likely an appropriate injection pressure at the needle tip confirm a correct needle tip position. In this framework, the injection pressure at the needle tip appears not only as a safety standard, but also as a useful tool to help in optimizing needle tip positioning in the ideal spot to maximize efficacy while preserving safety.

[0126] Patients' safety must always be the first concern for any medical professional. The introduction of ultrasound guidance alone, in clinical fields using interventional procedures such as regional anesthesia, has not been shown as effective per se in reducing the most feared complications, such as persistent and permanent nerve injuries. Continuous injection pressure precise measurement at the needle tip is a valuable tool to increase safety during invasive procedures, giving precious information about the location of the needle tip with respect to adjacent structures.

[0127] The existent device in the market does not provide this information: [0128] it does not measure the injection pressure at the needle tip, but along the injection line, which is less precise being affected by many different confusing variables; [0129] it does not measure the injection pressure continuously nor accurately, but it just provides three threshold which few studies have associated to different level of risk, regarding solely an intraneural positioning of the needle tip (thus it cannot be used to detect intravascular injections or to assist the operator in an optimal needle tip positioning); [0130] it does not provide any information about an injection pressure lower than normal; [0131] it is not ergonomically friendly, obliging the operator to intermittently check the visual indicator, which implies a momentary blind spot in ultrasound guidance with consequent danger of needle tip accidental displacement.

[0132] The new system described here has been specifically conceived to address and solve all these problems, with the double aim to increase both safety standard and accuracy of interventional procedure.