DEVICE FOR PROVIDING INTRAPLEURAL ANESTHESIA
The present invention relates to a device for pro¬ viding intrapleural anesthesia, said device comprising a valve with an inlet, a first and a second outlet, and a manually operable valve member communicating the inlet with either one of the outlets, and the outlets with one another.
Intrapleural anesthesia is a method for providing local anesthesia when the patient"nas a pain in one side of the chest or in the upper part of the abdomen. Anesthe¬ tic liquid is supplied intermittently or continuously by means of a catheter introduced between the pleura visce- ralis and the pleura parietalis through an incision be- tween the fourth and the eighth rib. Since the risk of in¬ juring the lung when positioning the catheter is consider¬ able, this operation requires great skill.
The object of the invention is to provide a device which appreciably facilitates insertion of the catheter in the pleura. The device is characterised in that one end of a cannula is detachably connected with the first outlet of the valve, the cannula being formed with a longitudinal bore starting from that end of the cannula which is con¬ nected with the valve outlet, and ending in an opening in the lateral surface of the cannula, near the opposite end of said cannula; that the inlet of the valve is situated opposite the first outlet and connectible therewith by means of a substantially rectilinear through channel in the valve member, for introducing in the bore of the can- nula a catheter to be guided out through the lateral open¬ ing via an- inclined, concave wall; and that an ascending tube or the like is connected with the second outlet.
The invention will be described in more detail below, reference being had to the accompanying drawings, in which Fig. 1 is a partly sectional side view showing an embodi¬ ment of the invention, Fig. 2 is an enlarged view of a
part of this embodiment, and Fig. 3 shows a variant of the the part shown in Fig. 2.
A conventional three-way valve 10 forms part of the device according to the invention and comprises a valve housing, an inlet 11, a first outlet 12, and a second out¬ let 13. As indicated at 14, a valve member is sealingly mounted in the valve housing and rotatable by finger-acti¬ vated operating means 15. The valve member is formed with the requisite channels for communicating the inlet with the two outlets, and the two outlets with one another. A cannula 18 is detachably connected with the first outlet 12, and an ascending tube 16 is connected with the second outlet 13.
Fig. 1 shows one of many different known ways of de- tachably and sealingly connecting the cannula 18 with the outlet 12 of the valve 10. Thus, the outlet 12 comprises a conical portion insertable in a corresponding opening in the end 19 of the cannula 18, the seal being established in that the -internal thread of a sleeve 17 rotatably ar- ranged on the outlet 12 engages with a flange 20 on the end of the cannula 18, such that, when the sleeve 17 is rotated, the conical portion of the outlet is pressed against the walls at the end of the cannula. The ascending tube 16 which, in a suitable conventional manner, is at- tached to the second outlet 13, is made of plastic and has an approximate length of 7-8 cm.
The cannula 18 has a longitudinal bore 25 starting from the end 19 of the cannula, or alternatively from the opening in said end adapted to receive the conical portion 26 of the outlet 12, and extends through the cannula to a point near the opposite, free end 23 of the cannula, where it ends in a lateral opening 22. At the side facing the end 23, the bore 25 is defined by a concave wall 24. As can be seen in Fig. 2, the end 23 of the cannula is round, while the wall 24 defining said opening is concave and in¬ clined forwards/outwards. As is plain from the following, both these distinctive features are important.
The inlet 11 of the valve 10 is adapted to receive, in a suitable and conventional manner, the discharge end of a means, preferably a syringe, discharging liquid. Thus, said inlet 11 may comprise an internal thread or a narrowing portion cooperating with the point of the sy- • ringe. Naturally, the inlet may also have external means adapted to engage with the means for liquid supply, the main thing being that liquid can be suitably supplied to the inlet 11 and be further conducted to the ascending tube 16, after the valve member 14 has been set by acti¬ vation of the operating means 15 to connect the second outlet 13 with the inlet 11.
The device also comprises a catheter 27, preferably a so-called epidural catheter, of a commerically available type. This catheter is made of a plastic material with suitable rigidity and has an outer diameter of about 1 mm. The catheter 27 is intended to be conducted through the bore 25 of the cannula 18 and out through the outlet open¬ ing 22. For this purpose, the valve member 14 has a straight, through opening connecting the inlet 11 with the outlet 12 in a rectilinear manner, such that the ca¬ theter 27 can be conducted along a substantially rectili¬ near path from the valve inlet 11, via the valve member 14, the valve outlet 12 and the cannula 18, all the way to the opening 22, where it is bent sideways when reaching the concave, inclined front wall 24, as illustrated in the drawings.
The device according to the invention is used in the following way for providing intrapleural anesthesia. First, a tiny incision is made in the skin between the fourth and the eighth rib. A suitable syringe whose outlet is connect¬ ible with the valve inlet 11, is filled with saline solu¬ tion or a local anesthetic. The valve member is turned, by activation of the operating means 15, in such a manner that the inlet 11 is connected with the second outlet 13, and the content of the syringe is injected into the ascending tube 16 up to a predetermined level therein. The front end
23 of the cannula 18 and the lateral opening 22 are then introduced under the skin through the incision, whereupon the valve member is turned so as to connect the first out¬ let 12, and consequently the cannula 18, with the second outlet 13 and the- ascending tube 16. The cannula 18 is slowly pushed through the soft part of the thoracic cavi¬ ty, and its round end 23 displaces the lung by a few mil¬ limetres without injuring it. When the lateral opening 22 of the cannula 18 is introduced in the pleural cavity, the subpressure therein causes the level of the liquid in the ascending tube 16 to sink somewhat; an indication that the cannula is in position. Then, the valve body is turned such that the inlet 11, as well as the two outlets 12, 13, are closed. The syringe attached to the inlet 11 is now remov- ed, whereupon the valve member 14 is again turned by acti¬ vation of the operating means 15 to a position in which the inlet 11 is connected with the outlet 12 via the straight through Opening in the valve member 14. Thereafter, the point of the catheter 27 is positioned in the inlet 11, near the valve body 14, whereupon the catheter is pushed through the opening in the valve member 14, the valve out¬ let 12, and the bore 25 of the cannula 18, the concave wall
24 directing it into the pleural cavity. Thus, the catheter is, in a very simple and gentle manner, introduced in the pleural cavity, the risk of injuries to the lung, or of air entering the pleura, being minimal. When the catheter end is in the desired position, the cannula is carefully re¬ tracted, at the same time as the catheter 27 is held firm¬ ly so that it stays in place. The cannula 18 and its ancil- lary parts can now be removed and the catheter 27 be fixed to the skin and connected to a supply of local anesthetic which then can be supplied continuously or intermittently. The cannula described above and shown in the drawings is made of metal and in one piece. An alternative embodi- ment is the two-part cannula shown in Fig. 3 and compris¬ ing a tubular standard cannula 30 whose bore 31 opens into the end of the cannula, and a terminal member 32 fixed to
the standard cannula and having a round end 33 and a chan¬ nel 34 ending in a lateral opening 35. The wall 36 of the cannula facing the round end is concave in a manner cor¬ responding to the wall 24 in the embodiment described above. The terminal member is, in a suitable fashion, fix¬ ed to the outside of the cannula 30, but it is also pos¬ sible to fix it to the inside thereof. In the embodiment shown in Fig. 3, the terminal member is suitably made of metal. It may also be made of plastic, but should in that case extend on the outside of the cannula 30 along the major part of the length thereof, advantageously all the way to the opposite end of the cannula, so as not to come loose.