US 3308819 A
Description (OCR text may contain errors)
March 14, 1967 L. J. ARP
ANESTHETIC DEVICE Filed Dec. 9, 1963 i 5m i a J KN wfflw mm 2 w J m R Q ,3
Z Mow v d fl United States Patent O 3,308,819 ANESTHETIC DEVICE Leon J. Arp, Ames, Iowa, assignor to Iowa State University Research Foundation, Inc., Ames, Iowa, a corporation of Iowa Filed Dec. 9, 1963, Ser. No. 328,999 3 Claims. (Cl. 128215) This invention relates to an anesthetic device, and, more particularly, to a catheter useful in the practice of cervical anesthesia.
In the labor period preceding childbirth, the cervix area is anesthetized, the anesthetic lasting for about one hour. At the present time, the block is delivered into the cervix area with a metal needle, and after the expiration of the dosage, the insertion procedure must be repeated. Because of the additional danger of an infection and the time and circumstances involved, it is desirable to be able to leave the needle in place so that additional anesthetic may be given whenever needed. However, a standard hypodermic needle cannot be left in place, even if a method were devised to maintain the proper one-half inch insertion depth, because of the potential danger to the infant by the sharp point during the delivery process.
The characteristics of the anesthetic delivery conduit meeting the above-described requirements pose a dilemma. If the conduit is rigid enough to remain immobilized, there is potential danger to the infant. On the other hand, if the conduit is made flexible or yielding, there is the possibility of loss of the conduit, with the attendant possibility of infection through repeated insertions, and, in fact, failure to achieve the principal objective of the conduit. It is, therefore, an important object of this invention to provide a solution to the dilemma just described through the provision of a flexible plastic-type conduit similar to that used in catheters and further characterized by unique means for preventing accidental withdrawal, but which coact with the catheter to permit deliberate withdrawal with a minimum of danger and further with minimum danger to the infant.
Another object of the invention is to provide a flexible catheter for use in conjunction with a hypodermic cannula in cervical anesthesia wherein the catheter is equipped with unique integral spurs adapted to be folded into an alternative position so as to facilitate removal of the catheter at the end of the use period.
Still another object is to provide a unique procedure for the administration of cervical anesthesia employing a novel catheter-like device for delivering the anesthetic to the cervix.
Other objects and advantages of the invention may be seen in the details of construction and operation set down in this specification.
The invention is explained in conjunction with an illustrative embodiment in the accompanying drawing, in which FIG. 1 is an elevational view, partially in dotted line, of a syringe equipped with the inventive catheter-like conduit;
FIG. 2 is a perspective view, on enlarged scale, of the conduit of FIG. 1;
FIG. 3 is a sectional view taken along the line 3-3 of FIG. 2;
FIG. 4 is a fragmentary sectional view taken along the sight line 4-4 applied to FIG. 3; and
FIG. 5 is an elevational view of the insertive parts of FIG. 1 but in exploded form.
In the illustration given and with particular reference to FIG. 1, the numeral designates generally a hypodermic syringe equipped with the usual barrel 11 terminating in a pointed cannula 12 and also equipped with Patented Mar. 14, 1967 a plunger 13 and finger-supporting portions 14. Arranged in ensleeved relation over the cannula 12 is the catheter-like conduit generally designated 15 and which can be seen in larger scale in FIG. 2 and exploded view in FIG. 5. The distal end of the conduit 15 is tapered as at 16 (see also FIG. 4). The conduit 15 is itself ensleeved by a penetration-limiting cannula 17, each of the cannulae being equipped with adapters as at 12a and 17a, respectively Additionally, the cannula 17 has a penetration-limiting hub 17b.
Intermediate the conduit ends are provided a plurality of spurs as at 18 and 19, which outstand from the outer wall 20 of the conduit 15. The conduit 15 is also equipped with an inner wall or bore 21, and the conduit 15 may be advantageously constructed of 0.027" ID. (#22) polyvinyl chloride or Teflon tubing.
The spurs 18 and 19 are seen to be spaced from, but adjacent to, the distal end 16, and are circumferentially spaced about the outer wall 20. Because of the thinness of the tube wall constituting the conduit 15, the spurs may be provided by slashes as at 18a and 19a, which may or may not extend completely through the tube wall (compare 18a and 19a in FIG. 4). Optimally, the slashes 18a and 19a defining the spurs 18 and 19 occupy a portion of the tube periphery more than and less than so as to substantially not interfere with the integrity of the conduit 15. The bottom of the slash is smooth or rounded as at 18b in FIG. 4. The round bottom can be obtained by making the cut with a hot wire, thereby making the cut by melting or vaporizing the plastic.
In the operation of the invention, the usual charge of anesthetic is placed within the barrel 11 of the hypodermic syringe 10 and the cannulae 12 and 17 directed toward the spot of administration, the catheter-like conduit 15 being positioned as seen in FIG. 1. After the anesthetic charge is delivered, the syringe 10 equipped with the cannulae 12 and 17 is removed both from the cervical region and the conduit 15, leaving the latter in place in the tissue to the proper depth. This depth is of the order of /2", and is maintained through the provision of the integral spur means provided adjacent the distal end of the conduit 15, the remaining 5 /2 or so of the conduit 15 being smooth. Any inadvertent movement against the conduit 15 will not result in its displacement, inasmuch as the spurs 18 and 19 serve as anchors. Ultimately, the conduit 15 is removed, after subsequent administrations of anesthetic if the same are called for, merely by pulling axially on the conduit 15, whereupon the spurs 18 and 19 fold over to the configuration indicated in dotted line and designated by the numeral 18c in FIG. 4. At this time, the infant has been delivered and the cervix is still anesthetized, so that there is no pain attendant on the removal of the conduit 15. Further, the folding over of the spurs 18 and 19 results in only a slight enlargement of the channel developed during insertion of the hypodermic cannnula 12.
On the other hand, during insertion, the spurs 18 and 19 fold into positions of conformity with the outer wall 20 so as to preclude any undesirable enlargement of the channel prior to the time the anesthetic is administered.
The use of the heated wire for providing the spurs 18 and 19 relieves the stresses which would otherwise be present at the apex of each slash, tending to disrupt or tear the spur. It will be appreciated that the hot wire technique can be utilized by molding to develop the same type of strainless configuration. This also permits the development of alternative configurations such as molded concentric rings.
While in the foregoing specification a detailed description of an embodiment of the invention has been set down for the purpose of explanation, many variations in the details herein given may be made by those skilled in the art without departing from the spirit and scope of the invention.
1. In combination, a hypodermic syringe equipped with a pointed cannula for the delivery of anesthetic, a unitary flexible plastic tube ensleeved about said cannula, said tube having integral spur means positioned adjacent the end of said cannula efiective to anchor said tube in position in cervical tissue when the cannula is removed from the tube.
2. The combination of claim 1 in which said cannula extends beyond the end of said tube.
3. In combination, a hypodermic syringe equipped with a first cannula having a pointed end for the delivery of anesthetic, a unitary flexible plastic tube ensleeved about said first cannula and terminating before said pointed end, and a second cannula ensleeved on said tube andterminating in a penetration-limiting hub before the end of said tube, the portion of said tube extending beyond said second cannula having integral spur means effective to anchor said tube in position in cervical tissue when said first and second cannulae are withdrawn from said tube.
References Cited by the Examiner UNITED STATES PATENTS 2,740,404 4/1956 Kohl 128-215 2,828,744 4/1958 Hirsh etal 12s 221 3,123,077 3/1964 Alcamo 12s 332.5
FOREIGN PATENTS 586,018 12/1924 France.
ROBERT E. MORGAN, Acting Primary Examiner.
D. L. TRULUCK, RICHARD A. GAUDET, Examiners.