Patent Description:
The invention relates to an intravenous catheter apparatus comprising a catheter hub arranged at a proximal end of a catheter tube and having an inner surface defining a chamber; a needle having a needle tip and extending through the chamber and the catheter tube when in a ready position; and a needle guard slidably arranged on the needle and received in the chamber when the needle is in its ready position, wherein the needle guard is configured to guard the needle tip upon withdrawal of the needle from the catheter hub.

An intravenous catheter apparatus of this kind is generally known. The needle guard serves to prevent a person handling the intravenous catheter apparatus from accidentally coming into contact with the needle tip after placement of the catheter tube in and subsequent removal of the needle from a patient's vein. Thereby, the intravenous catheter apparatus helps to avoid unwanted transmission of blood borne diseases.

A needle tip guard for use in a catheter device is known from <CIT>, in which the needle shaft is provided with an enlargement in order to prevent axial withdraw of the needle form the needle tip guard when the needle is received in the needle tip guard. Additionally, a distal wall of the needle tip guard blocks the needle tip when the needle is received in the needle tip guard. Thus, the needle can move within the needle tip guard between two positions, a first position in which the needle tip abuts the distal wall, and a second position in which the needle enlargement abuts a base portion of the needle tip guard.

Further, needle safety devices are known from <CIT> and <CIT>.

It is an object of the present invention to provide an intravenous catheter apparatus which provides better protection against accidental pricking by the needle tip and which is inexpensive to manufacture at the same time.

The object is satisfied by an intravenous catheter apparatus in accordance with claim <NUM>.

The intravenous catheter apparatus of the invention comprises:.

wherein preferably the base portion has an axial through-bore for receiving the needle, wherein the through-bore comprises first and second sections both having cross-sections that are larger than the principal profile of the needle, wherein the cross-section of the second section being larger than the cross-section of the first section.

According to an embodiment, the invention further provides a catheter hub arranged at a proximal end of a catheter tube and having an inner surface defining a chamber; a needle defining an axial direction and having a needle tip, wherein the needle extends through the chamber and the catheter tube when in a ready position; a needle guard slidably arranged on the needle and received in the chamber when the needle is in its ready position, the needle guard including a base portion and first and second arms extending from the base portion, wherein the first arm is deflected radially outwards by the needle against a restoring force when the needle is in its ready position whereby the needle guard is brought into retaining contact with the catheter hub; and retaining means for retaining the needle guard in the chamber as long as the first arm is in its deflected state. The retaining means include a first disc-like retaining protrusion provided on the first arm and a retaining depression formed in the inner surface of the catheter hub and adapted to receive the retaining protrusion.

The disc-like retaining protrusion has the benefit that it is in engagement along a circular contact surface with the corresponding retaining depression formed in the inner surface of the catheter hub. Differing from IV catheter apparatuses as known from the prior art, this provides an engagement between the needle guard and the catheter hub along a substantial annular portion of the retaining protrusion and the retaining depression which provides a safe and reliable engagement between the two components as long as the needle guard is in its ready position and is to be prevented from being retracted out of the needle hub. Even if the needle guard is rotated within the catheter hub, this secure engagement between the catheter hub and the needle guard holds the needle guard safely within the catheter hub.

Because of a depression being formed in the inner surface of the catheter hub for retaining the needle guard in the chamber, instead of e.g. a protrusion, the catheter hub can be manufactured more easily and, thus, at less manufacturing cost, in particular if the catheter hub is a plastic part and e.g. formed by injection molding. At the same time the particular design of the first retaining protrusion provided on the needle guard ensures effective engagement of the retaining protrusion with the retaining depression and, thus, reliable retaining of the needle guard in the catheter hub. Hence, the risk of premature release of the needle guard from the catheter hub during withdrawal of the needle from the catheter hub and, thus, the risk of accidental pricking by the needle is reduced.

According to a preferred embodiment, the retaining protrusion is of part-circular, in particular semi-circular shape. More specifically, the retaining protrusion may have generally parallel proximal and distal faces and/or a convex, in particular partcylindri-cal, peripheral surface.

According to another embodiment, the first retaining protrusion is arranged in the region of a distal end of the first arm.

According to yet another embodiment, a second disk- like retaining protrusion is arranged on the second arm and adapted to engage with the retaining depression as long as the first arm is in its deflected state.

According to yet another embodiment, the second arm can be deflected, preferably along its entire length, radially inwards when the needle tip is received between the arms, to thereby allow the second retaining protrusion to disengage from the retaining depression.

According to yet another embodiment, the second retaining protrusion is arranged in the region of a distal end of the second arm. In particular, the second retaining protrusion may be arranged opposite from the first retaining protrusion.

According to yet another embodiment, the retaining depression is an at least part annular depression, preferably an annular depression.

According to yet another embodiment, the restoring force is created by at least one of an elastic property of the first arm and an additional tension element. For example, the needle guard may comprise a tension element at least partly surrounding the arms in a region proximal of the first retaining protrusion or - instead of surrounding the two arms - biasing the two arms by a linear biasing action. Alternatively or additionally, the first and second arms can be made of a resilient material.

According to yet another embodiment, the first and second arms are made of a plastic material. Preferably, the first and second arms are integrally formed with the base portion also made of a plastic material, e.g. by injection molding.

According to the invention, the needle comprises an engagement means provided at a distance from the needle tip for engaging with the needle guard and preventing the needle guard from sliding off the needle. Preferably, the engagement means is formed of by enlargement of the radial dimension of the needle in at least one direction as compared with a principal profile of the needle. The engagement means can be found by a local crimp, a shoulder, a bulge formed as an annular widening etc..

According to yet another embodiment, the needle guard comprises a stopping element engaging with the engagement means of the needle when the needle tip is received between the first and second arms. Preferably, the stopping element defines an axial bore having a cross-section adapted to the principal profile of the needle but being smaller than the enlargement of the needle. Furthermore, the stopping element may be made of a material different from the material of the base portion, in particular of a metal material. The stopping element may be of disc-like shape or tubular shape and/or arranged on a distal side of the base portion. It can be fixed in the base portion or supported in a floating manner on the needle.

A preferred embodiment of the invention will now be described by way of example only with reference to the accompanying drawings.

<FIG> shows an intravenous catheter apparatus comprising a catheter tube <NUM> and a catheter hub <NUM> attached to the catheter tube <NUM> at a proximal end thereof. It will be appreciated that the term 'proximal' refers to a position or orientation close to a person handling the intravenous catheter apparatus whereas the term 'distal' refers to a position or orientation distant from this person, wherein the longitudinal direction A of a needle <NUM> is the reference direction.

The catheter hub <NUM> has an inner surface <NUM> which defines a chamber <NUM> of generally circular cross-section. The chamber <NUM> is located in a proximal section of the catheter hub <NUM>. In a distal region of the chamber <NUM> the inner surface <NUM> of the catheter hub is provided with an annular retaining depression <NUM> the function of which will be discussed in more detail further below.

The needle <NUM> having distal and proximal ends extends through the chamber <NUM> of the catheter hub <NUM> as well as through the catheter tube <NUM>. The needle <NUM> comprises a needle shaft <NUM> and a needle tip <NUM> at its distal end. A needle hub <NUM> is attached to the proximal end of the needle <NUM>. The needle <NUM> defines said axial (longitudinal) direction A and the needle shaft <NUM> has a generally constant principal profile, except for an enlargement of the radial dimension of the needle <NUM> in at least one direction as compared to the principal profile, which is positioned in the region of the needle tip <NUM> and forms an engagement means (not shown). Preferably, the engagement means is made by crimping of the needle <NUM>. However, it could also be made by welding, milling, cold heading or expanding of the needle. The function of the engagement means will be discussed in more detail further below.

<FIG> shows the intravenous catheter apparatus in a condition prior to use, in which the needle <NUM> extends all the way through the chamber <NUM> of the catheter hub <NUM> as well as the catheter tube <NUM> and the needle tip <NUM> protrudes from a distal end of the catheter tube <NUM>. This position of the needle <NUM> is also referred to as the ready position in this context. It is to be noted that the needle <NUM> is fixed in its ready position by the needle hub <NUM> engaging with the catheter hub <NUM>.

In order to prevent accidental pricking by the needle <NUM> prior to use of the intravenous catheter apparatus, a tubular cover <NUM> covers the catheter tube <NUM> and the portion of the needle <NUM> extending therethrough. A proximal end portion of the cover <NUM> is removably fixed to a distal end portion of the catheter hub <NUM>.

The intravenous catheter apparatus further comprises a needle guard <NUM> for protecting the needle tip <NUM> after use of the needle <NUM>, i.e. after placement of the catheter tube <NUM> in and withdrawal of the needle <NUM> from a patient's vein. The needle guard <NUM> is slidably arranged on the needle shaft <NUM> and received in the chamber <NUM>.

As can be seen in more detail in <FIG>, the needle guard <NUM> comprises a tubular base portion <NUM> and first and second arms <NUM>, <NUM> extending from a distal side of the tubular base portion <NUM> generally in the axial direction. The base portion <NUM> and the arms <NUM>, <NUM> are integrally made of a plastic material, for example by injection molding.

The base portion <NUM> has an axial through-bore <NUM> for receiving the needle <NUM>. The through-bore <NUM> comprises first and second sections <NUM>, <NUM> both having cross-sections that are larger than the principal profile of the needle <NUM>, the cross-section of the second section <NUM> being even larger than the cross-section of the first section <NUM>.

A stopping element <NUM> in the shape of a disk-like plate, such as a washer, is arranged at the distal side of the base portion <NUM>, for example by insert molding. The stopping element <NUM> is made of a material different from the material of the base portion <NUM>, for example of a metal material. The stopping element <NUM> has an axial bore <NUM> which is aligned with the through-bore <NUM> of the base portion <NUM> and which has a cross-section which is smaller than that of the through-bore <NUM> of the base portion <NUM>. More specifically, the cross-section of the axial bore <NUM> of the stopping element <NUM> is adapted to the principal profile of the needle <NUM> such that the stopping element <NUM> can slide along the needle shaft <NUM> with minimum friction. However, a maximum dimension of the axial bore <NUM> transverse to the longitudinal direction A is smaller than a maximum dimension of the engagement means provided on the needle <NUM> transverse to the longitudinal direction so as to prevent the engagement means from passing through the stopping element <NUM> and, thus, to prevent the needle guard <NUM> from sliding off the needle <NUM>.

The first arm <NUM> of the needle guard <NUM> is longer than the second arm <NUM> and has a massive distal end section <NUM> having an undercut <NUM> for catching the needle tip <NUM>. The distal end section <NUM> is angled towards the second arm <NUM> and overlaps with the second arm <NUM> (<FIG>). In its ready position the needle <NUM> extends completely through the needle guard <NUM> (<FIG>). In this situation the distal end section <NUM> of the first arm <NUM> is supported on the needle shaft <NUM> thereby deflecting the first arm <NUM> radially outwards. In order to facilitate deflection of the first arm <NUM>, the first arm <NUM> has a narrowed portion <NUM> of reduced cross-section approximately in a middle region of the arm <NUM>. In contrast to the first arm <NUM> and because of a lack of angled distal end section, the second arm <NUM> is not significantly deflected by the needle <NUM> extending through the needle guard <NUM>. Nonetheless, the second arm <NUM> has a similar narrowed portion <NUM> the reason for which will become apparent further below.

Even though the first and second arms <NUM>, <NUM> have certain elastic properties, a tension element, for example a rubber band <NUM>, surrounds a distal section of the arms <NUM>, <NUM> such that deflection of the first arm <NUM> occurs mainly against a restoring force of the tension element (<FIG>).

When the needle <NUM> is withdrawn from the catheter tube <NUM> after placement of the catheter tube <NUM> in a patient's vein, the needle <NUM> slides through the needle guard <NUM> until the needle tip <NUM> passes the angled distal end section <NUM> of the first arm <NUM>. At this point the angled distal end section <NUM> is no longer supported on the needle shaft <NUM> and the first arm <NUM> - mainly by force of the rubber band <NUM> - snaps back into its relaxed state with the angled distal end section <NUM> now blocking the needle tip <NUM>. According to the invention, the length of the first arm <NUM> and the distance of the engagement means from the needle tip <NUM> are adapted to each other such that the needle tip <NUM> received in the needle guard <NUM> has a minimum of clearance with respect to axial movement in the needle guard <NUM>.

In order to prevent the needle guard <NUM> from being prematurely removed from the chamber <NUM> of the catheter hub <NUM>, i.e. before the needle tip <NUM> is covered by the needle guard <NUM>, the first arm <NUM> is provided with a disc-like first retaining protrusion <NUM> engaging with the retaining depression <NUM> in the inner surface <NUM> of the catheter hub <NUM> in the deflected state of the first arm <NUM>. The first retaining protrusion <NUM> has generally flat proximal and distal faces <NUM>, <NUM> and a convex, in particular part-cylindrical, peripheral surface <NUM> the radius of which is adapted to the radius of the inner surface <NUM> of the catheter hub <NUM> in the region of the retaining depression <NUM>. The height of the first retaining protrusion <NUM>, i.e. its dimension seen in the radial direction, is adapted such that the first retaining protrusion <NUM> disengages from the retaining depression <NUM> when the first arm <NUM> snaps back into its relaxed state.

The second arm <NUM> is provided with a disc-like second retaining protrusion <NUM> which is similar to the first retaining protrusion <NUM> and which extends in a radial direction opposite from the first retaining protrusion <NUM>. The second retaining protrusion <NUM> also has generally parallel proximal and distal faces <NUM>, <NUM> as well as a convex, in particular part-cylindrical, peripheral surface <NUM>. The height of the second retaining protrusion <NUM>, i.e. its dimension seen in the radial direction, is adapted such that the retaining protrusion <NUM> engages with the retaining depression <NUM> when the needle <NUM> is in its ready position. In order to disengage the retaining protrusion <NUM> from the retaining depression <NUM>, the second arm <NUM> can be deflected slightly radially inwards towards the needle <NUM> when the pulling force on the needle <NUM> becomes great enough.

Claim 1:
An intravenous catheter apparatus comprising:
a catheter hub (<NUM>) arranged at a proximal end of a catheter tube (<NUM>), the catheter hub (<NUM>) having an inner surface (<NUM>) defining a chamber (<NUM>);
a needle (<NUM>) defining an axial direction and having a needle tip (<NUM>), the needle (<NUM>) extending through the chamber (<NUM>) and the catheter tube (<NUM>) when in a ready position;
a needle guard (<NUM>) slidably arranged on the needle (<NUM>) and received in the chamber (<NUM>) when the needle (<NUM>) is in the ready position, the needle guard (<NUM>) including a tubular base portion (<NUM>) and first and second arms (<NUM>, <NUM>) extending from the tubular base portion (<NUM>), wherein the first arm (<NUM>) is deflected radially outwards by the needle (<NUM>) against a restoring force when the needle (<NUM>) is in the ready position whereby the needle guard (<NUM>) is brought into retaining contact with the catheter hub (<NUM>),
wherein the needle (<NUM>) comprises an engagement means (<NUM>) provided at a distance from the needle tip (<NUM>) for engaging with the needle guard (<NUM>) and preventing the needle guard (<NUM>) from sliding off the needle (<NUM>),
characterized in that
the length of the first arm (<NUM>) and the distance of the engagement means (<NUM>) from the needle tip (<NUM>) are adapted to each other such that the needle tip (<NUM>) received in the needle guard (<NUM>) has a minimum of clearance with respect to axial movement in the needle guard (<NUM>).