HRP20090463A2 - Curved dilator for targer thoracic drainage - Google Patents

Abstract

The present invention discloses a curved dilator for targeted thoracic drainage consisting of a partially curved body (1). That body (1) is from the edge (7) to the position (2) of constant diameter and is straight; and the distance from the edge (7) to position (2) makes 40-60% of the total length of the dilator. The tapered mouth (6) is located behind the edge (7) and narrows to the width of the channel (5) to guide the wire. From position (2) to position (3), the dilator is curved for an angle α≥80 °, and an angle ß of about 60 ° defines the total length of the dilator. The diameter of the dilator body (1) progressively decreases from position (2) to tip (4) in such a way that it is slightly larger than the width of the channel (5) at the very tip (4). The role of the tapered mouth (6) is to facilitate the introduction of the wire and visual control of the operator on the position of the wire in the chest. From the tapered mouth (6) to the very tip of the dilator (4), the channel diameter (5) decreases progressively by 2-3 times to a diameter that is finally slightly larger than the diameter of the guide wire, which prevents the wire from accumulating in the dilator.

Description

The field of technology

The present invention relates to a curved dilator and its use in a targeted thoracic drainage procedure. The technical field to which the invention belongs can be classified into devices for introducing media into or out of the body. Additionally, the subject of the invention can be classified as a device for introducing, guiding and positioning a catheter in thoracic drainage.

Technical problem

The technical problem solved by the present invention relates to the improvement (shortening) of the thoracic drainage procedure. In the procedure, a curved dilator is used to place a thoracic drain. The technical problem solved by the subject invention is the more accurate and simpler placement of the guide wire for the drain in the desired quadrant of the patient's chest, and later the drain, which is used to drain air or liquid from the chest.

State of the art

Considering the number of thoracic drainages in European countries, which is approximately one procedure per 1,000 inhabitants per year, it can be assumed that the state of the art is relatively rich. Thoracic drainage is most often performed by two methods; classic surgical technique and technique with the help of a guide wire. In the paper "Targeted wire-guided chest tube placement: a cadaver study"; Protić A. and others; European Journal of Emergency Medicine (in the process of publication); the precision of targeted placement of a thoracic drain with the help of a wire-guide (Targeted wire-guided technique-TWG) compared to classical surgical technique (CS) was discussed. The work showed a significantly higher reliability (precision) of the TWG technique compared to the CS technique, approximately 79% success rate of TWG compared to 30% success rate of CS. It is important to mention that the precise placement of the thoracic drain could significantly affect the quality of thoracic drainage in both emergency and less urgent patients.

The TWG technique, i.e., the procedure and kit for performing it, is given, for example, in a US patent published in 1987 as US 4,813,929; inventor Semrad, N. The described procedure consists of introducing a wire through a cavity created by a needle in the chest, making an incision parallel to the patient's ribs in the vicinity of the introduced wire, introducing a catheter along the "wire" and removing the wire, and introducing additional tubes into the chest.

Today, standard medical practice includes dilators for chest drain placement. With the mentioned technique, we use thicker or thinner dilators, of axisymmetric shape, without curvature along the basic axis - which widen the "hole" made in the chest area. With such "straight" dilators, it is not possible to significantly influence the direction of movement of the guide wire, and thus neither the subsequent position of the drainage catheter. The subject invention precisely discloses a curved dilator that solves that technical problem.

Curved dilators were previously known in percutaneous tracheotomy procedures (creation of an artificial opening in the neck - trachea) and placement of a plastic cannula through which life-threatening patients can breathe more easily. As such, curved dilators serve solely as expanders of the surrounding tissue that the guidewire directs during penetration. Such curved dilators are not able, and have no need, to change the direction of passage of the guide wire during percutaneous tracheotomy. They are made entirely of relatively soft materials whose sole purpose is to increase the base diameter at the trachea for placement of the plastic cannula while being guided along the guide wire.

One such dilator is found in the "Ciaglia Percutaneous Tracheostomy Introducer Set" sold by Cook Critical Care and shown in Figure 1. Another such improved dilator is shown in patent issued 6,637,435 (COOK INCORPORATED) and sold under the trade name BLUE RHINO® . The name of the curved dilator comes from the external appearance of the horn of a rhinoceros (lat. rhinoceros) and is the closest state of the art, and is shown in Figure 2. Its main advantage is the reduction of the number of used dilators when performing the percutaneous tracheotomy procedure. However, due to its relatively soft tip, the said dilator is used in this procedure only after an initial expansion is made with another (harder and smaller) dilator that is large enough to insert the said dilator. Unlike the curved dilators mentioned above; the curved dilator according to the subject invention significantly directs the guide wire, thereby increasing the success of the performed procedure. In addition, its internal structure prevents the guide wire from "creasing" in the body of the dilator and enables precise guidance in the desired chest quadrant.

Furthermore, its tip is significantly harder than the tips of all the mentioned existing curved dilators, which is why it is no longer necessary to use smaller and harder dilators for the initial expansion of the opening after the introduction of the needle, which is a common practice today when introducing existing curved dilators. An additional advantage of the invention in question is the fact that it enables a significant reduction of the time required for the introduction of the chest drainage tube, because two or more dilators no longer have to be used to gradually widen the opening, but it is sufficient to use only the invention in question for this purpose.

The essence of invention

The curved dilator for targeted thoracic drainage consists of the partially curved dilator body shown in Figure 3. The tapered mouth is located at the posterior edge of the dilator and tapers to the width of the wire guide channel. The dilator is curved for an angle α ≥ 80°, and the angle β, which is about 60°, defines the total length of the dilator. The diameter of the dilator body progressively begins to decrease after the flat part of the dilator in such a way that at the very tip that first enters the chest, the dilator itself is slightly larger than the width of the channel for guiding the wire. The role of the conical mouth is to facilitate the introduction of the wire and the operator's visual control of the position of the guide wire in the chest. The channel for the guide wire is from the conical mouth to the very tip of the dilator of such a diameter that it progressively decreases towards the tip of the dilator, where it is only slightly larger than the diameter of the wire. Such channel construction prevents the accumulation of the guide wire in the dilator.

Brief description of the drawing

Drawing 1 and Drawing 2 show prior art - longitudinal sections of known curved dilators found in the art for the percutaneous tracheotomy procedure.

Figure 3 shows a curved dilator for targeted thoracic drainage according to the present invention. Drawing 4 shows the rear part of the dilator according to the present invention, while Drawing 5 shows the tip of the dilator which is introduced into the chest.

Detailed description of the invention

A curved dilator for targeted thoracic drainage is shown in Figure 3. It consists of a body (1) that is of substantially constant diameter from edge (7) to position (2). After position (2), a progressive narrowing of the outer diameter of the body (1) of the dilator begins and gradually bends with it by an angle α, ending possibly at position (3), while the outer diameter decreases all the way to the very top of the dilator (4).

A channel (5) for the guide wire passes through the entire body of the dilator (1), which starts behind the conical mouth (6) with the outer edge (7). The channel (5) is from the conical mouth (6) to the very tip of the dilator (4) with a diameter that progressively decreases towards the tip of the dilator (4). In this way, the diameter of the channel (5) is only slightly larger than the diameter of the wire at the said tip (4) and possibly about 2-3 times narrower than at the conical mouth (6). Such channel construction prevents the accumulation of the guide wire in the dilator.

The maximum curvature of the dilator, marked by the angle α, is calculated according to the tangents that define the beginning and end of the curved parts of the dilator. Comparing with the state of the art, we find the following values:

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The dimensions of the dilators from the prior art are different since these dilators are adapted to another type of procedure - percutaneous tracheotomy. For this reason, we do not make a dimensional comparison with the dilator, which is the subject of the invention, because it has a different purpose.

According to the preferred embodiment of the invention, the length of the body of the dilator (1) from the beginning - the edge (7) - to the position (2) (when the dilator begins to bend) is approximately 90 mm and this part is of constant diameter and looks like a flat cylinder. This length can of course be longer or shorter, and position (2) is located at a position that is approximately 40%-60% of the total length of the dilator measured from the edge (7) to the top (4). In practice, it has been shown that 90 mm is the most ergonomically acceptable length for safe manipulation of the dilator. Within those 90 mm, there is a conical mouth (6) with a depth of about 9 mm, where the outer diameter of the mouth (6) is about 9 mm and narrows to about 3 mm, which is the initial width of the channel (5) - see Drawing 4. Corner β which defines the subject length of the tip (4) in the present invention is about 60°±10°. The final part of the dilator that is introduced into the chest is almost without curvature - from position (3) to the very top (4) and is about 15 mm. The width of said channel (5) at the very top of the dilator (4) is about 1 mm. The largest diameter of the body (1) of the dilator at the very beginning is about 10 mm and remains constant until position (2). The edge (7) is made as a circular wreath with a thickness of about 0.5 mm. The diameter of the body (1) of the dilator begins to progressively decrease from position (2) all the way to the top (4). The total length of the dilator from the edge (7) to the top (4) is about 200 mm. The tip itself is made in such a way that it is slightly wider than the channel (5), as shown in Drawing 5.

Of course, it is possible to form a channel (5) with a constant diameter from the conical mouth (6) to the tip (4) - but such a dilator is somewhat more difficult to mass produce. Its technical performance would be almost the same as that of the preferred performance.

The advantages of this designed curved dilator for targeted thoracic drainage are multiple. The dilator in question enables precise guidance of the guide wire into the appropriate quadrant of the patient's chest with the standard function of expanding the created cavity on the chest.

It should be noted that state-of-the-art dilators do not (in)guide the guide wire but along the introduced guide wire and perform dilatation on such a well-defined trajectory. For this reason, the dilators discussed in the prior art have a relatively soft tip (4) and a significantly wider channel (5) than in the subject invention. In order to be able to "manage" the wire without piling up the wire in the body of the dilator, a conical mouth for receiving the wire was made. This conical mouth (6) enables the operator to visually inspect the condition of the wire and eliminates the possibility of the guide wire piling up in the dilator. The greater curvature of the dilators according to the invention compared to state-of-the-art dilators, α≥80°, is also visible, which is necessary for two reasons; the first is the specificity of performing the thoracic drainage procedure and guiding the wire inside the chest, and the second is the possibility of imagining the position of the tip (4) by the operator, which is difficult for α<80°.

The dilator according to the present invention can be made of medically acceptable materials such as, for example, "Radiopaque polyethylene", a material common for the production of existing flat and solid dilators, or some other suitable material can be used. The use of such a material will enable the tip of the curved dilator to be strong enough to safely carry out the opening dilation procedure, but at the same time flexible enough that it cannot break during manipulation (as with solid plastic dilators), and that it cannot lead to damage in the chest during manipulation of the dilator in order to position the wire in the desired chest quadrant. In the same way, the material from which the dilator is formed can be some other material that contrasts for ultrasound or X-ray.

It is also desirable (but not a requirement) that the dilator according to the subject invention be coated with a hydrophilic layer from position (2) to the top (4) in order to facilitate penetration and dilation into the chest and thereby reduce damage to the surrounding tissue. Such hydrophilic coating of dilators is known in the state of the art, see, for example, the procedure for applying a hydrophilic layer described in US 6,637,435 (column 4, line 7-22).

It is desirable that the dilator has markings on its part of the body (1) that extends from the edge (7) to position (2) that tell the operator in which direction the dilator is curved. These marks can be made as visual marks - for example, in a different color; tactile protrusions or some other technique that eliminates doubt in the position of the tip (4) once introduced into the patient's chest.

Applicability

The actual use of the dilator according to the present invention is as follows; after the introduction of the guide wire into the pleural space via the needle according to the previously described technique (see the state of the art), the expansion of the small hole through which the guide wire passes is performed with a curved dilator according to the subject invention - which remains in the chest until the bend on the dilator, somewhere around the position ( 2). After that, the wire guide is pulled out to the 200 mm mark (dilator length). By rotating around the axis of the handle of the curved dilator, we direct the tip of the dilator towards the desired quadrant in the chest. To place a thoracic drain in the sense of air drainage in the chest (pneumothorax), the tip of the dilator is directed from the front and up. To place a thoracic drain in terms of fluid drainage, the tip of the dilator is directed backwards and downwards. In both cases, the wire guide is again placed deep into the chest up to the 350 mm mark parallel to the end of the curved dilator, which assumes that the guide wire will reach the desired position. When the curved dilator is removed, a thinner thoracic drain is placed in the chest to drain air from the chest or a thicker thoracic drain to drain fluid in the chest.

It is assumed that the application of the described invention facilitates and improves the procedure of thoracic drainage. Thoracic drainage has so far proven to be an extremely invasive procedure with limited success that can only be performed by well-educated medical personnel. By applying a curved dilator during the thoracic drainage procedure, the described technique could be significantly extended (if clinical studies confirm it) to less educated medical personnel, while at the same time increasing reliability and thus a better effect of the placed thoracic drain. Indications for thoracic drainage are broad and include: traumatic and spontaneous pneumothorax, traumatic bleeding into the chest, malignant and other pleural effusions.

The described dilator according to the present invention is dimensioned to form a part of the kit for carrying out thoracic drainage.

Claims (7)

1. A curved dilator for targeted thoracic drainage consisting of a body (1) that is partially curved, characterized in that: - from edge (7) to position (2), body (1) has a constant diameter and is in the shape of a flat cylinder; and the distance from the edge (7) to position (2) makes 40-60% of the total length of the dilator; - that the conical mouth (6) which is located along the edge (7) is narrowed to the width of the channel (5) for guiding the wire; - that from position (2) to position (3) the dilator is curved by an angle α≥80°, and that the angle β is 60°±10° and defines the total length of the dilator; and - that the diameter of the body (1) of the dilator progressively decreases from position (2) to the top (4) so that at the very top (4) it is slightly larger than the width of the channel (5) for the guide wire. 2. Curved dilator for targeted thoracic drainage according to claim 1, characterized in that the conical mouth (6) facilitates the introduction of the wire into the channel (5) and the operator's visual control of the position of the wire in the chest, where the diameter of said channel (5) from the conical mouth (6) to the very top of the dilator (4) progressively narrows 2-3 times to a diameter slightly larger than the diameter of the guide wire - which prevents the wire from piling up in the dilator. 3. Curved dilator for targeted thoracic drainage according to claim 2, characterized in that the channel (5) of constant cross-section is slightly larger than the guide wire from the conical mouth (6) to the tip of the dilator (4). 4. Curved dilator for targeted thoracic drainage according to claim 1-3, characterized in that it is partially coated with a hydrophilic layer and made of material that is ultrasound and X-ray contrast. 5. Curved dilator for targeted thoracic drainage according to claims 1-4, characterized in that the body (1) has visual and/or tactile markings of the direction of curvature of the tip (4). 6. The use of a curved dilator for targeted thoracic drainage according to claims 1-5, indicated by the fact that it is used in the following indications: traumatic and spontaneous pneumothorax, traumatic bleeding into the chest, malignant and other pleural effusions, in a way that, in addition to expanding the hole made on the chest is used for targeted guidance of the guide wire in the desired quadrant of the patient's chest. 7. Use of a curved dilator for targeted thoracic drainage according to claims 1-5, characterized in that it forms part of a thoracic drainage kit.