The present invention relates to a hand-held device for inserting a needle into a non- homogeneous material, particularly for intravenous catheterization.

EP 0 730 880 A, on which the preamble of independent claims 1 and 5 is based, discloses a manual catheterization device provided with an actuated needle retraction mechanism. This known device aims at improving the catheterization process as it helps the medical technician to properly dispose of the needle to avoid a needlestick with a contaminated needle. The device includes a generally hollow barrel that houses a needle hub. A needle is affixed to the distal end of the needle hub and is aligned to extend through an opening in the distal end of the barrel. The needle extends through a catheter hub and a catheter affixed to the catheter hub. The device further includes a spring that is disposed in the barrel lumen to cooperate with the needle hub to urge the latter toward the proximal end of the barrel. A latch actuator is releasably engaged with the catheter hub. A latch which cooperates with the latch actuator is movable between a first position in which it maintains the needle hub adjacent to the distal end of the barrel and a second position allowing the spring to urge the needle hub to the proximal end of the barrel. Due to the vibrations inducted by the activation of the spring the operator may experience discomfort during the needle insertion process or during the needle extraction process after the puncture. Moreover, such a known device has no capability to guide insertion of the needle into the material.

It is therefore an object of the present invention to provide a hand-held device for precisely positioning a tip of a needle in a non-homogeneous material, particularly for intravenous catheterization, which is safer and more comfortable to use than the prior art discussed above.

This and other objects are fully achieved according to the present invention by virtue of a device having the features set forth in independent claims 1 and 5.

Advantageous embodiments of the invention form the subject-matter of the dependent claims, the content of which is to be intended as forming an integral part of the following description.

In short, the invention is based on the idea of providing a device comprising decoupling or actuating means operatively arranged between the needle and the casing for decoupling the needle from the casing, so that the needle does not move as a single piece with the casing along its longitudinal axis, or for moving the needle in a controlled manner along its longitudinal axis in the opposite direction relative to the casing during the insertion process, respectively, as well as detection means configured to detect a condition where the needle tip has reached a target position in the non-homogeneous material and control means which are operatively connected with said decoupling or actuating means and said detection means and are configured to operate said decoupling or actuating means upon detection by said detection means that the needle tip has reached the target position. By virtue of such a configuration, the device of the invention allows to introduce the needle within the target non-homogeneous material stopping the needle tip in the correct position or retracting it even though the operator moves the casing of the device forwards into the material. This is especially helpful when performing for example intravenous catheterization, in particular on difficult patients such as paediatric, elderly or diabetic patients. Moreover, with the use of such a device less training is required from the operator to achieve good injection results.

Further features and advantages of the present invention will become apparent from the following detailed description, given purely by way of non-limiting example with reference to the appended drawings, where:

Figure 1 schematically shows a hand-held device for inserting a needle into a non- homogeneous material according to the present invention;

Figures 2a and 2b are schematic views showing a first embodiment of a device according to the invention, in a first operating condition where the needle is coupled to the casing of the device and in a second operating condition where the needle is decoupled from the casing, respectively;

Figure 3 is a schematic views showing a second embodiment of a device according to the invention, in the above-mentioned second operating condition;

Figures 4a and 4b are schematic views showing a third embodiment of a device according to the invention, in the above-mentioned first and second operating conditions, respectively;

Figure 5 is a schematic view showing a fourth embodiment of a device according to the invention;

Figures 6a, 6b and 6c are schematic views showing a fifth embodiment of a device according to the invention, in a first operating condition where the needle and the catheter are both coupled to the handle and the casing is freely movable relative to the support member along the longitudinal axis of the needle, in a second operating condition where the needle tip has reached a blood vessel and the main body is locked to the support member and in a third operating condition where, with the main body still locked to the support member, the handle is advanced to move the catheter further into the vessel and at the same time the needle is retracted, respectively;

Figures 7a, 7b and 7c are schematic views showing a sixth embodiment of a device according to the invention, in said first, second and third operating conditions, respectively; and

Figures 8a, 8b and 8c are schematic views showing a seventh embodiment of a device according to the invention, in said first, second and third operating conditions, respectively.

The present invention will be described hereafter with specific reference to its application to the catheterization process, i.e. the insertion of a catheter within a blood vessel. This specific application is however to be construed as not limiting the scope of the invention, since the invention may be used in many other applications, such as for example tissue biopsy (e.g. from a brain, liver, etc.), brachytherapy, i.e. the insertion of radioactive seeds inside that the patient for cancer treatment, blood sampling, i.e. the insertion of a needle within a blood vessel, or spinal cord puncture.

Figure 1 shows a very schematic representation of a hand-held catheterization device according to the present invention (hereinafter simply referred to as "the device"), where the device is generally indicated 10. With reference to Figure 1, the device 10 basically comprises a main body or casing 12 (hereinafter referred to simply as casing), which is suitably sized to be held by the operator's hand, and a shaft 14, which is partially received within the casing 12 and carries at its distal end a needle 16 having a tip 18 and a catheter 20 disposed around the needle 16. The longitudinal axis of the shaft 14 is indicated x, while the longitudinal axis of the needle 16 is indicated x'. The longitudinal axes x and x' are parallel to each other and may also coincide with each other (as in the example illustrated in Figure 1).

The shaft 14 is normally coupled to the casing 12, so that it is moved by the operator as a single piece with the casing 12. The shaft 14 can however be decoupled from the casing 12, once the needle tip 18 has reached a target position, for example a blood vessel, by means of a unit 22 (acting in this case as a decoupling unit), so that it is no more coupled to the casing 12 and is therefore free to move relative to the casing 12 along the direction of its longitudinal axis x. Once the shaft 14, and therefore also the needle 16 carried by it, is decoupled from the casing 12, a possible further forward movement of the casing 12 caused by the operator is no longer transmitted to the needle 16, and therefore the needle tip 18 remains at the target position irrespective of possible movements of the casing 12 caused (either intentionally or unintentionally) by the operator. The device 10 further comprises a control unit 24 (for example a microcontroller) configured to control the decoupling unit 22 to decouple the shaft 14, and therefore also the needle 16 and the catheter 20 carried by the shaft 14, from the casing 12 when the needle tip 18 has reached the target position (that is to say, in case of a catheterization device, a blood vessel). In order for the control unit 24 to be informed about the needle tip 18 reaching the target position, the device 10 further comprises a sensor unit 26 arranged to measure a physical characteristic of the material at the needle tip 18, such as for example an electrical impedance, a pressure, a colour, a temperature, etc., or to measure a vibration, a sound, a force change, etc., and to send corresponding signals to the control unit 24. Based on the signals received by the sensor unit 26, the control unit 24 is able to discriminate between different materials at the needle tip 18 to determine whether the needle tip 18 has reached the target position. In case for example of a sensor unit 26 made as an impedance sensing circuit and of a target position constituted by a blood vessel, the control unit 24 will analyze the impedance signals provided by the sensor unit 26 and determine whether they are within the range of blood. In the affirmative, the control unit 24 will command the decoupling unit 22 to decouple the shaft 14, and therefore also the needle 16, from the casing 12.

The device 10 is preferably battery-operated by means of an embedded rechargeable or replaceable battery back (not shown). Alternatively, the device 10 may be powered by an external DC adapter. With reference now to Figures 2a and 2b, a first embodiment of the invention is shown, where the device 10 is configured to insert a catheter 20 into a vein V. Figure 2a shows the device 10 before the needle 16 has punctured the vein V, while Figure 2b shows the device 10 once the needle 16 has punctured the vein V and the needle tip 18 is therefore within the vein V.

According to this embodiment, the decoupling unit 22 comprises an electrical clutch that is normally engaged and clamps therefore the shaft 14, so that the shaft 14 is normally coupled to the casing 12 (Figure 2a). When activated, the electrical clutch unclamps the shaft 14, thereby allowing the shaft 14, and hence the needle 16 and the catheter 20 with it, to freely move along its longitudinal axis x relative to the casing 12 at least in one direction (Figure 2b), so that if the operator moves the casing 12 further towards the vein V, the shaft 14 may retract inside the casing 12 thereby allowing the needle tip 18 to remain in the target position in the vein V. As far as the sensor unit 26 is concerned, it includes an impedance sensor contained in a concentric electrode needle 28 to measure the electrical impedance between the needle tip 18 and the needle shaft. The concentric electrode needle 28 is plugged onto a connector element 30 which is in turn mounted onto the distal end of the shaft 14 through a connecting member 32, so that the concentric electrode needle 28 is drivingly connected to the shaft 14. The sensed electrical impedance signal is transferred from the sensor unit 26 to the control unit 24, in order for the latter to be able to determine whether the needle tip 18 has reached a vein and, if so, to activate the electrical clutch to decouple the shaft 14 from the casing 12. Figure 3, where parts and elements identical or corresponding to those of Figures 2a and 2b are designated with the same reference numerals, shows a second embodiment of the invention which differs from the first embodiment of Figures 2a and 2b in that the sensor unit 26 is arranged to detect the acoustic or near-acoustic signal generated by the puncture of the vein, i.e. the so-called "pop" sound described by practitioners or the needle vibration.

In this case, the sensor unit 26 comprises a microphone for acquiring and using the acoustic signals and an appropriate signal processing system configurator to distinguish the sound generated when penetrating the vein from other noises generated when penetrating adjacent tissues. The sensor unit 26 may also comprise filters configured to remove these other noises and thus improve the signal-to-noise ratio. Such an acoustic based detection system may be used as an alternative to the impedance-based detection system described above in connection with the first embodiment of Figures 2a and 2b or as a further detection system in addition to the above impedance-based detection system.

With reference now to Figures 4a and 4b, where parts and elements identical or corresponding to those of Figures 2a and 2b are designated with the same reference numerals, a third embodiment of the invention is shown therein, which differs from the first embodiment of Figures 2a and 2b substantially only in the structure of the decoupling unit 22.

In this third embodiment, in fact, the decoupling unit 22 is formed by a pressurized container of tubular shape which is mounted in the casing 12 so as to move as a single piece with it and defines a central passage 34 through which the shaft 14 extends. When pressurized, the container clamps the shaft 14 inside the passage 34 so that the shaft 14 is fixed to the casing 12 (Figure 4a). However, when deflated to a low pressure (as a result, for example, of puncturing), the container does not clamp the shaft 14 anymore and the shaft 14 is thus free to move relative to the container, and therefore relative to the casing 12 (Figure 4b). In this case, the control unit 24 controls the decoupling unit 22 so as to cause deflation of the pressurized container when the control unit 24 determines, based on the signals received from the sensor unit 26, that the needle tip 18 has reached the target position. Accordingly, even though the operator pushes the casing 12 further towards the vein V, or more generally towards the material into which the needle tip 18 has to be inserted, the needle tip 18 is not moved along with the casing 12, but remains in the target position.

With the reference now to Figure 5, where parts and elements identical or corresponding to those of the preceding Figures have been given the same reference numerals, according to a further embodiment of the invention the device comprises an actuating unit 22', instead of the decoupling unit 22, which actuating unit 22' is formed by a motorized linear mechanism arranged to move the shaft 14 to and fro along the longitudinal axis x under control of the control unit 24 to keep the needle tip 18 in the target position, for example in a fixed position inside the vein V, automatically compensating for any possible forward or backward motion of the casing 12 produced by the user.

The motorized linear mechanism may for example comprise an electric motor 36 and a screw and nut mechanism for converting a rotational motion of a screw 38 driven into rotation by the electric motor 36 into a translational motion of a nut 40 along an axis coinciding with, or more generally parallel to, the longitudinal axis x of the shaft 14, the nut 40 being secured to, or alternatively formed in one piece with, the shaft 14. By controlling rotation of the electric motor 36 in one direction or in the opposite direction, the control unit 24 causes the needle 16 to move to and fro relative to the casing 12, in order to automatically insert the needle 16 into the vein V or withdraw the needle 16 from the vein V and/or to actively keep the needle 16 in a fixed position inside the vein V irrespective of any possible movements of the casing 12 produced by the user. In order for the control unit 24 to suitably control the electric motor 36 to keep the needle 16 in a fixed position compensating for any possible movements of the casing 12 produced by the user, the device 10 further includes an axial force sensor 42 or a position sensor 44 to sense the force applied by the user on the casing 12 once the needle tip 18 has reached its target position in the vein V.

According to the illustrated embodiment, the device 10 is also able to withdraw the needle 16 from the vein V while inserting the catheter 20 into the vein V. In this case, the motorized linear mechanism is activated by the control unit 24 to withdraw the shaft 14, and hence also the needle 16, at a higher rate compared to the forward movement of the casing 12 produced by the user, so that the needle 16 is drawn back from the vein V, once the needle tip 18 has punctured the vein, while at the same time the catheter 20 is pushed forward by the casing 12 and thus enters the vein V.

Further embodiments of a device according to the invention, comprising an actuating unit arranged to actively move the shaft, and hence the needle, to and fro relative to the casing to compensate for any possible movements of the latter, and wherein the catheter may be inserted into the vein while at the same time the needle is withdrawn from the vein, are illustrated in Figures 6a to 6c, 7a to 7c and 8a to 8c, where parts and elements identical or corresponding to those of Figure 5 have been given the same reference numerals.

With reference first to the embodiment shown in Figures 6a to 6c, the device 10 further comprises a handle 46 operable by the user (or, alternatively, by a suitable linear actuator, such as for example an electromechanical linear actuator) and a support member 48 that are both slidably mounted on the casing 12 for sliding relative to the latter in a direction parallel to the longitudinal axes x and x'. The handle 46 is connected to the shaft 14 by means of a swing arm 50 which is hinged at its centre to the casing 12 at a fulcrum F and is hinged at its opposite ends to the handle 46 and to the shaft 14, so that a longitudinal movement of the handle 46 in one direction relative to the casing 12 causes a longitudinally movement of the shaft 14 in the opposite direction relative to the casing 12. The support member 48 may be coupled to the casing 12 by means of a clutch lever 52 hingedly mounted on the casing 12. The support member 48 is intended to be brought in contact with the material (for example the patient's skin) into which the needle tip 18 has to be inserted, in order to facilitate support of the device 10 during insertion of the needle 16 into the material. A fork-like locking member 54 operated by a solenoid 56 is operatively associated to the swing arm 50 to lock the latter and prevent it from rotating about its fulcrum F, as shown in Figure 5a. The solenoid 56 is also configured to control movement of the clutch lever 52 between a first operating position (Figure 6a), in which the clutch lever 52 does not engage the support member 48 and therefore does not prevent the latter from sliding relative to the casing 12, and a second operating position (Figures 6b and 6c), in which the clutch lever 52 engages the support member 48 to couple the latter to the casing 12. When the solenoid 56 is deactivated, it keeps the locking member 54 in a locking position in which the locking member 54 locks the swing arm 50. At the same time, the clutch lever 52 is in the above-mentioned first operating condition. On the other hand, when the solenoid 56 is activated, it moves the clutch lever 52 in the above-mentioned second operating position and at the same time moves the locking member 54 away from the locking position to allow rotation of the swing arm 50 about its fulcrum F.

When the solenoid 56 is deactivated (see Figure 6a), and hence when the swing arm 50 is locked by the locking member 54 and the clutch lever 52 is in the above-mentioned first operating position, the operator acting on the handle 46 may move the needle 16 and the catheter 20 towards the vein V while the support member 48 is in contact with the patient's skin, as the clutch lever 52 allows movement of the casing 12, and hence of the shaft 14, relative to the support member 48. Upon the detection by means of the sensor unit 26 that the needle tip 18 has reached the vein V, the control unit 24 activates the solenoid 56, so that the swing arm 50 is no more locked by the locking member 54 and can therefore rotate around its fulcrum F, while the clutch lever 52 is moved to the second operating position to couple the support member 48 the casing 12 (Figure 6b). Accordingly, the needle 16 is prevented from advancing further into the vein V.

At this point, as shown in Figure 6c, further forward movement of the handle 46 by the operator (or, alternatively, by means of electrical power from an embedded battery pack or from external connection) causes on the one hand a corresponding forward movement of the catheter 20 into the vein V and on the other a pivoting motion of the swing arm 50 about the fulcrum F, and therefore withdrawal of the needle 16 from the vein V.

The device of Figures 6a to 6c thus allows to perform the following three distinct actions: i) decoupling of the needle 16 from the casing 12 to avoid target overshooting;

ii) withdrawal of the needle 16; and

iii) insertion of the catheter 20, this action being performed at the same time as action ii). The device 10 may be provided with optional LED outputs (not shown) to show that the needle tip 18 has reached the target position, as detected by the sensor unit 26. LED outputs may also provide indications relating to any one of the following states of the device:

a) device 10 ready / not ready;

b) needle 16 coupled to / decoupled from the casing 12;

c) catheter 20 locked / released; and

d) battery level.

The device may also be connected to an external computer system (not shown), either wireless or wired, for real-time transmission of the measurements taken by the sensor unit and/or of internal parameters representing the operating state of the device and for remote control operation.

The embodiment of Figures 7a to 7c differs from the embodiment of Figures 6a to 6c mainly in that the swing arm as a means for converting the translational motion of the handle 46 in one direction into the translational motion of the shaft 14 in the opposite direction is replaced by a gear mechanism comprising a gear wheel 58, which is idly rotatably supported by the casing 12 and meshes both with a first rack 60 of the handle 46 and with a second rack 62 of the shaft 14, and in that the locking member 54 is made as a braking pad arranged to lock the gear wheel 58 by applying on the latter a friction torque. Also in this embodiment the clutch lever 52 and the locking member 54 are controlled by the solenoid 56 in such a manner that when the solenoid 56 is deactivated (Figure 7a) the clutch lever 52 does not engage the support member 48 and the locking member 54 locks the gear wheel 58, whereas when the solenoid 56 is activated (Figures 7b and 7c) the clutch lever 52 engages the support member 48 and the locking member 54 unlocks the gear wheel 58.

Finally, Figures 8a to 8c show a further embodiment that differs from the embodiment of Figures 7a to 7c substantially only in that the gear mechanism as a means for converting the translational motion of the handle 46 in one direction into the translational motion of the shaft 14 in the opposite direction is replaced by a belt mechanism comprising a wheel 64 and a belt 66 which is attached at a first end thereof to the handle 46, passes around the wheel 64 and is attached at the opposite end to the shaft 14. Also in this case the wheel 64 may be locked by a locking member 54 made as a braking pad.

As far as the sensor unit 26 is concerned, the description provided above with reference to the embodiments of Figures 2a and 2b and Figure 3 applies also to the other embodiments of the invention shown in Figures 4a to 8c.

In view of the above description, the advantages of the invention over the prior art are evident. First of all, by virtue of its sensor unit, that allows to determine whether the needle tip has reached the target position, and of the decoupling or actuating unit, that allows to decouple the needle from the casing of the device and hence to avoid target overshooting, even though the operator moves the device further towards the material, or to actively move the needle to and fro relative to the casing, the device of the invention allows operators, even those not very skilled, to precisely position the needle tip in the desired position and to keep the needle tip in this position, thereby significantly lowering work stress of the operators, in particular when difficult patients (such as children, elderly people or diabetic patients) have to be treated. Furthermore, the device of the invention has a lightweight and compact structure that facilitates handling of the device by the operator and is also not expensive to manufacture.

Naturally, the principle of the invention remaining unchanged, the embodiments and the constructional details may vary widely from those described and illustrated purely by way of non-limiting example, without thereby departing from the scope of the invention as defined in the appended claims.