Patent Application
20130025588
1. Technical Field
This application relates to a loading dilator for dilating an opening in the body of a patient for a medical use. More particularly, the invention relates to a loading dilator having a variable diameter transition segment at a distal portion thereof for use in positioning a medical device, such as a tracheostomy tube, across the body opening.
2. Background Information
The creation of an adequate air passageway is a critical step in maintaining the ability of a seriously ill or injured patient to breathe, or in performing resuscitation on a patient unable to breathe. Endotracheal intubation (the placement of a tube through the nostrils or mouth and into the trachea itself) is a widely-used method for establishing an air passageway. However, in order to establish an optimal air passageway for endotracheal intubation, the trachea, nostrils and/or mouth must normally be free, or at least substantially free, of obstruction. When an obstruction is present, endotracheal intubation is not generally possible, and an alternative passageway for airflow must be established.
The most direct way to provide an air passageway under these circumstances is to form an opening, or stoma, through the tracheal wall. Once formed, a tracheostomy tube is inserted through the opening. Conventional tracheostomy tubes often include an open distal aperture and a circumferential inflatable cuff. The cuff provides a seal between the tracheal wall and the tracheostomy tube at a location proximal to the distal aperture. The seal prevents the intrusion of blood, tissue or foreign matter into the lower trachea, bronchi and lungs, while permitting complete control and monitoring of the airflow established through the tracheostomy tube, including the provision of positive pressure ventilation. The open distal aperture provides a passageway for air into the lungs of the patient.
Several methods and devices are known for forming, or enlarging, an opening in a tracheal wall. In one such method, a scalpel is used to form a small opening in the tracheal wall. A needle is inserted through the small opening, such that the tip of the needle is in the interior space of the trachea. A wire guide is then passed into the trachea through a bore in the needle, and the needle is thereafter withdrawn. Sequentially sized dilators are then advanced over the wire guide to facilitate gradual dilation of the tracheal entrance to an appropriate size.
Recently, a single curved dilator, sold by Cook Incorporated of Bloomington, Ind., under the name BLUE RHINO®, has been developed that avoids the necessity of utilizing multiple dilators. The BLUE RHINO® dilator, so called because its shape resembles the horn of a rhinoceros, has a distal end portion that is curved in a substantially continuous manner, wherein an increasingly larger diameter portion of the dilator may be inserted into the trachea, thereby facilitating clearance of the posterior tracheal wall. Further description of the BLUE RHINO® dilator is provided in U.S. Pat. No. 6,637,435, incorporated by reference herein.
Another method for forming or enlarging an opening in a tracheal wall for introduction of a tracheostomy tube is described in U.S. Pat. No. 5,653,230, incorporated by reference herein. This method employs a balloon catheter having an inflatable balloon at a distal end of the catheter. The catheter is inserted over a percutaneously inserted wire guide, and the catheter is advanced along the wire guide until the balloon lies across the tracheal wall. The balloon is then inflated to radially dilate a portion of the tracheal wall, thereby forming an opening in the wall that corresponds to the inflated diameter of the balloon.
Following formation of the opening by any of the known methods, an introducer/loading dilator is pre-loaded with a tracheostomy tube, and the distal end of the apparatus is passed through the opening over the previously-inserted wire guide. It is desirable to provide a loading dilator/tracheostomy tube combination that has a generally smooth transition from loading dilator to tube, thereby facilitating entry of the distal, or leading, end portion of the tube through the opening. However, since there are a number of different sizes and manufacturers of tracheostomy tubes, there is a possibility that a significantly-sized lip (resulting from the respective differences in diameter between the loading dilator and the leading end of the tracheostomy tube) may be present at the transition between the loading dilator and the distal end of the tracheostomy tube. One example of a lip L is illustrated in
It would be desirable to provide a loading dilator that is sized to accommodate tracheostomy tubes having a range of diameters, and that is structured to minimize the transition between the loading dilator and the tracheostomy tube upon insertion of a dilator/tracheostomy tube apparatus.
The problems of the prior art are addressed by the features of the present invention. In one form thereof, the invention comprises a loading dilator for positioning a tubular medical apparatus across an opening formed through a body wall of a patient, wherein the tubular medical apparatus is sized to fit over a portion of the loading dilator during positioning of the apparatus. The loading dilator comprises an elongated body having a proximal end, a distal end, a relatively rigid proximal portion extending in a distal direction from the proximal end, a distal portion extending in a proximal direction from the distal end, and a passageway between the proximal and distal ends. The distal portion has a first relatively flexible segment and a second relatively rigid segment. The second segment comprises at least one of a curved portion and a tapered portion. The first segment is positioned intermediate the proximal portion and the second segment along a length of the elongated body. The first segment is axially extendable from a first length wherein the first segment has a greater diameter than a diameter of the second segment, to a second length wherein the first segment has a diameter that does not substantially exceed the diameter of the second segment.
In another form thereof, the invention comprises an assembly for use in providing ventilation to a patient through an opening in the tracheal wall of a patient. The assembly comprises a loading dilator having an elongated body having a proximal end, a distal end, a relatively rigid proximal portion extending in a distal direction from the proximal end, a distal portion extending in a proximal direction from the distal end, and a passageway between the proximal and distal ends. The distal portion has a first relatively flexible segment and a second relatively rigid segment. The second segment has at least one of a curved portion and a tapered portion. The first segment is positioned intermediate the proximal portion and the second segment along a length of the elongated body and is selectively movable between a first length wherein the first segment has a greater diameter than a diameter of the second segment, and a second length wherein the first segment has a diameter that does not substantially exceed the diameter of the second segment. A stylet is received in the passageway. The stylet has a proximal end extending proximal of the elongated body proximal end, and a distal end. The stylet is movable in the passageway relative to the elongated body between a first position wherein the first segment has the first length, and a second position wherein the stylet distal end exerts an axially displacing force on the second segment such that the first segment is movable from the first length to the second length.
In yet another form thereof, the invention comprises a method for positioning a medical apparatus across an opening formed in a body wall of a patient. A loading dilator assembly is positioned to receive the medical apparatus thereon. The loading dilator assembly includes an elongated body having a proximal end, a distal end, a relatively rigid proximal portion extending in a distal direction from the proximal end, a distal portion extending in a proximal direction from said distal end, and a passageway between the proximal end and the distal end. The distal portion comprises a first relatively flexible segment and a second relatively rigid segment. The second segment has at least one of a curved portion and a tapered end portion. The first segment is positioned intermediate the proximal portion and the second segment along a length of the elongated body and is selectively movable between a first length wherein the first segment has a greater diameter than a diameter of the second segment, and a second length wherein the first segment has a diameter that does not substantially exceed the diameter of the second segment. A stylet is disposed in the passageway of the elongated body. The stylet has a proximal end extending proximal of the elongated body proximal end, and a distal end extending along the passageway. The stylet is advanced in a distal direction in the passageway from a first position wherein the first segment has the first length, to a second position wherein the stylet distal end exerts an axially displacing force relative to the second segment such that the first segment moves to the second length. The medical apparatus is advanced over an outer surface of the elongated body such that a leading end of the medical apparatus is positioned over the first segment. The stylet is withdrawn such that the axially displacing force is relaxed, whereby the first segment retreats from the second position and conforms to a position of the leading end of the medical apparatus, thereby forming a substantially nontaumatic transition between the elongated body distal end and the leading end of the medical apparatus.
For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It should nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.
In the following discussion, the terms “proximal” and “distal” are used to describe the axial ends of the loading dilator, as well as the axial ends of related components. The “proximal” end is used in conventional manner to refer to the end of the dilator (or component) that is closest to the operator during use of the loading dilator. The “distal” end is used in conventional manner to refer to the end of the loading dilator (or component) that is initially inserted into the patient, or that is closest to the patient.
Prior art loading dilator 100 includes an elongated body 102 having a distal portion 104 that is tapered for ease of entry into the dilated opening previously formed in the tracheal wall. A passageway (not shown) extends through loading dilator 100 for passage of a wire guide (not shown) therethrough. Typically, elongated dilator body 102 is gently curved at the distal end portion to ease entry of the tracheostomy tube through the tracheal wall, and to generally conform to the anatomy within the cavity of the trachea.
In order to accommodate patients of varying sizes, loading dilators and tracheostomy tubes are provided in a variety of different diameters. Ideally, the respective diameters of the loading dilator and the tracheostomy tube will be substantially matched, such that there is only a minimal diametrical transition between the loading dilator and the distal end of the tracheostomy tube. As a result, the trauma experienced by the patient upon insertion of the tracheostomy tube through the tracheal wall will be minimized. However, due to the wide variance in diameters between the loading dilators and tracheostomy tubes that may be available to the physician in the operating room at any one time, it may not be possible to closely match the diameters of the respective loading dilators and/or tracheostomy tubes available to the physician. In some cases, selection of an available loading dilator and tracheostomy tube may result in the presence of a lip, or a significant diametrical difference between the loading dilator and the distal end of the tracheostomy tube at the transition.
A loading dilator/tracheostomy tube combination having a lip “L” is shown in the prior art combination of
In the embodiment shown, loading dilator 20 comprises an elongated body 22 having a proximal portion 23 and a distal portion 27. Proximal portion 23 extends to a proximal end 24, and distal portion 27 extends to a distal end 28. Distal portion 27 comprises a first segment 32 and a second segment 34, as further described herein. A finger grip element, such as finger grip 21, is affixed to loading dilator proximal end 24.
Proximal portion 23 of the dilator body is formed from any relatively rigid, medical grade, synthetic material known in the art for such use in forming a loading dilator. PVC and polyurethane are two non-limiting examples of suitable materials. Proximal portion 23 may have a length of about 12 to 18 cm, although those skilled in the art will appreciate that this length may be varied if desired.
As stated above, distal portion 27 comprises first and second segments 32 and 34. As shown in
First segment 32 is formed from a material, such as silicone, having a lower rigidity (i.e., a greater flexibility) than the material of proximal portion 23 and second segment 34. First segment 32 has sufficient elasticity to allow axial extension upon application of a force thereon. Other non-limiting examples of suitable materials for first segment 32 include low durometer polyurethanes as well as various thermoplastic elastomers having sufficient capability for stretching as described herein. Those skilled in the art will appreciate that other biocompatible elastic materials capable of flexure and extension as described may also be substituted for silicone.
When first segment 32 is in the relaxed configuration shown in
In order to interconnect the proximal portion 23, first segment 32, and second segment 34, as shown, the respective proximal and distal ends of flexible first segment 32 may be affixed to corresponding axial ends of proximal portion 23 and second segment 34. Those skilled in the art will appreciate that there are many suitable ways to accomplish these connections in a secure manner. In one such manner, small diameter plastic tubing, such as cannulae 40, 44 (
A suitably-sized segment 32 of silicone or other flexible material having a passageway extending therethrough is fitted between proximal portion 23 and second segment 34. The respective ends of segment 32 securely receive cannulae ends 41, 45. The respective ends of this segment may then be affixed to the corresponding ends of proximal portion 23 and second segment 34, and to respective cannulae ends 41, 45 by known means, such as by an adhesive or mechanical bonding. Each of the outer axial ends of first segment 32 (approximately 0.5 cm of each end) is preferably tapered or chamfered prior to assembly to provide a smooth transition between the ends of segment 32 and respective proximal portion 23 and second distal segment 34 as shown in
As stated above, an elongated generally rigid member, such as stylet 50, is slidably received in the passageway extending along the interior of elongated body 22. As shown in
Initially, the proximal end of the stylet (e.g., at button 53) extends a distance of about 4-5 cm proximal of loading dilator proximal end 24, as shown in
As stated, loading dilator assembly 10 may be used for inserting a tubular medical apparatus across an opening formed through a body wall of a patient. One example of such use is the insertion of a tracheostomy tube 80 across an opening formed through the tracheal wall. Tracheostomy tubes are well known in the medical arts, and tracheostomy tube 80 may be of any size and shape commonly utilized in the art. In the embodiment shown in
When utilized in combination with loading dilator assembly 10, tracheostomy tube 80 (
The following example provides additional details of the use of the loading dilator assembly in combination with a tracheostomy tube. Those skilled in the art will appreciate that with minor modification to the process steps described, the loading dilator assembly can be utilized to insert other tubular medical apparatuses across openings formed in other body walls.
The insertion of a tracheostomy tube through an opening in a tracheal wall is a well-known technique, and as such, the skilled artisan is well equipped to determine appropriate means for forming a suitable opening through the tracheal wall. In one known technique, a wire guide 90 (
A loading dilator assembly 10 as described hereinabove is arranged for insertion into the opening 94 formed through the tracheal wall. Stylet 50 is axially advanced with force F to axially displace loading dilator first segment 32 from the relaxed position as shown in
At this time the assembly 10, including tracheostomy tube 80 fitted thereover, is positioned for advancement into tracheal opening 94. The proximal end of wire guide 90 is back loaded into loading dilator distal end 28, and threaded through the assembly. The assembly and tracheostomy tube are advanced over the wire guide in well-known fashion, until the tracheostomy tube is properly positioned along the tracheal wall as shown in
Once insertion is complete and the tracheostomy tube has been properly positioned, the loading dilator assembly may be removed. Axial force F is once again asserted on button 53, so that stylet 50 is once again urged in the distal direction to displace first segment 32 to the stretched position shown in
As stated above, tracheostomy tubes are well known in the medical arts, and are provided in many different sizes and shapes. In the embodiment illustrated in
Another common tracheostomy tube configuration is shown in
Those skilled in that art will appreciate that the foregoing detailed description should be regarded as illustrative rather than limiting, and that it should be understood that it is the following claims, including all equivalents, that are intended to define the spirit and scope of this invention.
