US3477437A - Thoracentesis apparatus - Google Patents

Description

Nov. 11, 1969 A. M. GOLDBERG 3,477,437

THORACENTESIS APPARATUS Filed June :50, 1967 FIG.

INVENTOR All A II. 60103576 odd/ 1 flTTORA/EY United States Patent 3,477,437 THORACENTESIS APPARATUS Allan M. Goldberg, Sepulveda, Califi, assignor, by mesne assignments, to American Hospital Supply Corporation, a corporation of Illinois Filed June 30, 1967, Ser. No. 650,370 Int. Cl. A61b 17/34; A61m 25/00 US. Cl. 128-347 7 Claims ABSTRACT OF THE DISCLOSURE This invention relates to thoracentesis apparatus normally used to remove unwanted liquid from a patients lung cavity.

A thoracentesis procedure involves entering a patients lung cavity with a hypodermic needle on an end of a hypodermic syringe. A doctor pushes a pointed end of the needle into the patients back until it protrudes slightly into the patients pleural (lung) cavity. By using the hypodermic syringe and a valve arrangement between the syringe and needle, he can suck out the unwanted liquid. The system is airtight so liquid surrounding the lung can be pumped out without letting air enter the lung cavity where it could cause the lung to collapse.

One of the problems with thoracentesis apparatus has been concentrated in the needle. The pointed end of the needles cannula cannot protrude too far into the lung cavity or the cannula might rip into the lung as it swings back and forth as the patient breathes. Thus, the doctor had to be extremely careful to kep the cannula inserted to just the proper depth. This was difiicult, particularly since the doctor had to longitudinally push and pull on the syringes plunger to pump out the liquid. As a makeshift precaution against shoving the cannula into the patient too far, some doctors clamped a hemostat around the cannula after he found the proper depth.

There were disadvantages to using a hemostat in this manner. First, a hemostat is quite heavy and when it is hanging on a needle inserted into the patient, it could aggravate the patients pain. Secondly, a hemostat is an expensive instrument and cannot be economically provided in a one-time-use disposable kit or tray comprised solely of disposable items. Also, if the hemostat jaws were firmly clamped on a thin-walled metal cannula they might crush the cannula.

To overcome these disadvantages in the hemostate clamped onto the cannula arrangement, I have invented a simple disposable clamp that fits onto the cannula of a thoracentesis apparatus after its pointed cannula end has been inserted into a patient. My invention can be better understood with reference to the attached drawings, in which:

FIGURE 1 is a side elevational view of the thoracentesis apparatus showing the cannula inserted into the patients pleural cavity;

FIGURE 2 is an enlarged view of my disposable depth gauge attached to a cannula of the apparatus; and

FIGURE 3 is a cross-sectional view of the disposable depth gauge and cannula.

Turning now to the drawings, the thoracentesis apparatus includes a hypodermic needle 1 with a cannula 2 and 3,471,437 Patented Nov. 11, 1969 a hub 3 attached to one end of the cannula. A pointed opposite end 4 of the cannula penetrates into a patients pleural cavity 5 and this cannula has a bore 13 adapted to carry out liquid 6 surrounding lung 7.

This liquid is sucked out by a hypodermic syringe 9 which is connected to needle 1 through a valve 10. This valve has at least three ports and one of the ports connects to discharge tube 11. The doctor removes liquid 6 by pulling the syringes plunger rearwardly to fill the syringe with liquid 6. Next, he turns valve 10 so the syringe 9 and discharge tube 11 are connected. As he pushes forward on the plunger, he expels the liquid through discharge tube 11. Now, by turning valve 10 so the syringe 9 and cannula 2 are connected, he can again fill syringe 9 with liquid 6. This cycle is repeated until the doctor has sufiicient liquid removed from pleural cavity 5.

As can be seen, the doctor is longitudinally pushing and pulling on the syringe plunger through this cycle. If he is not extremely careful he might push cannula 2 too far into the patients lung cavity where it could injure lung 7.

To avoid this, I have provided an open wound metal coil spring 8 which firmly wedges onto the cannulas smooth outer surface. This coil spring can be attached to the cannula after the cannula is inserted into the patient. If the depth setting has to be adjusted, the doctor can longitudinally slide the coil spring 8 along the cannula to make the adjustment.

The coil spring in its relaxed condition as shownin FIGURE 3 has adjacent coils separated by a distance a, that is .005 inch to .025 inch less than the cannulas outer diameter. As the interference between the adjacent coils and the cannula is small, the wire of the relatively stiff coil spring 8 does not crush the thin wall of the cannula. The wire in the coil spring has a diameter of between .040 inch and .080 inch. The thin Wall of the cannula is between .005 inch and .020 inch. The coil spring is made of a wire which has a diameter at least one half as large as the cannulas outer diameter so that adjacent coils present rounded surfaces that can easily Wedge onto the cannulas rounded outer surface 15.

In the above specification and drawings, I rave used a specific embodiment to illustrate my invention. It is understood that persons skilled in the art can make certain modifications to this embodiment without departing from the spirit and scope of this invention.

I claim:

1. In an apparatus adapted to extract liquid from a patients body, the improvement of: a needle which includes an elongated hollow cannula with a puncturing point on one end and an enlarged hub on an opposite end, said cannula having a smooth constant diameter outer surface extending between its pointed end and its hub; and an open wound coil spring clipped onto the smooth outer surface of the cannula between the pointed end of the cannula and the enlarged hub, said coil spring extending laterally from the cannula and forming a depth limit stop that can be attached to and longitudinally adjusted along the cannulas length after a portion of the cannula adjacent its pointed end has been inserted into a patient.

2. An improvement in the apparatus as set forth in claim 1 wherein the cannula has a thin metal wall surrounding a bore through the cannula, and wherein the open wound coil spring is formed of a metal wire substantially thicker than said cannula wall.

3. An improvement in the apparatus as set forth in claim 2 wherein the cannula wall is between .005 inch and .020 inch and the coil spring is of a metal wire that has a thickness between .040 inch and .080 inch.

4. An improvement in the apparatus as set forth in claim 1 wherein the open wound coil spring has a distance between two adjacent coils in their relaxed unstretched condition that is .005 inch to 0.25 inch less than the cannulas outside diameter, which two coils can grippingly engage the cannulas outer surface without crushing the cannula.

5. An improvement in the apparatus as set forth in claim 1 wherein the open wound coil spring is formed of metal wire with a round cross-section which has a diameter at least One half as large as the cannulas outside diameter so as to present opposed rounded surfaces on adjacent coils between which the cannulas rounded outer surface can wedge.

6. Thoracentesis apparatus adapted to extract liquid from a pleural cavity of a patient, said apparatus comprising: a hypodermic syringe; a valve having at least three ports, one port connected to a forward end of the syringe; a discharge tube connected to a second port of the valve; a hypodermic needle connected to a third port; said hypodermic needle including a hollow metal cannula with a wall surrounding a cannula bore that is in axial alignment with said hypodermic syringe, said cannula having a smooth constant diameter outer surface that extends between a pointed puncture point at a 25 forward end of the cannula and an enlarged hub secured to an opposite rearward end of the cannula, said hub attaching the hypodermic needle to the third port of the valve; and an elastic op'en wound coil spring clipped onto the cannulas smooth outer surface between the pointed end of the cannula and the enlarged hub, said '4 coil spring extending laterally from the cannula and forming a depth limit stop that can be attached to and longitudinally adjusted along the cannulas length after a portion of the cannula adjacent its pointed end has been inserted into a patient, said open wound coil spring having two adjacent coils that have a distance between them which is .005 inch to .025 inch less than the cannulas outside diameter, whereby the two coils can grippingly engage the cannula without crushing the cannula.

7. Thoracentesis apparatus as set forth in claim 6 wherein the open wound coil spring is formed of metal wire with a round cross-section which has a diameter at least one half as large as the cannulas outside diameter so as to present opposed rounded surfaces on the two adjacent coils between which the cannulas rounded outer surface can wedge.

References Cited UNITED STATES PATENTS 20 1,43 6,707 11/ 1922 Gaschke 12822l 2,001,638 5/1935 TornSjO 128-347 2,338,800 1/1944 Burke 128--215 FOREIGN PATENTS 86,474 11/ 1895 Germany.

3 us. 01. X.R.

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