US 3529596 A
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United States Patent Charles G. Garner Fort Worth, Texas 718,404
April 3, 1968 Seat. 22, 1970 Lynn E. Bennett Fort Worth, Texas inventor App]. No. Filed Patented Assignee AUTOMATIC INTERMITTENT TRACHEOTOMY TUBE CUFF INFLATOR-DEFLATOR 3 Claims, 5 Drawing Figs.
U.S. C1 128/ 145.6, 128/351 Int. Cl A6lm 16/00, A61m 25/00 Field otSearch 128/145.5 145.8.
 References Cited UNITED STATES PATENTS 3,173,418 3/1965 Baran 128/351 3,211,152 10/1965 Stern 128/351 3,407,817 10/1968 Galleher... 128/351 3,461,877 8/1969 Morch 128/351 Primary Examiner-Charles F. Rosenbaum Attorney-Herbert J. Brown ABSTRACT: An automatic tracheotomy cuff inflator-deflator for use in conjunction with a cycling respirator that insures against damage to the trachea and aspiration of foreign matter into the lungs. Generally, the invention is comprised of a pneumatic cylinder with a piston operated by the control line from the respirator which inflates and deflates the tracheotomy cuff in response to the cycle of the respirator.
Patented SeptQZZ, 1 970 7 3,529,596
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I k 1e u 2 .ii 2.9 23/ 28 a l 2/ I CHARLES 6. GARNER ATTORNEY INVENTOR.
AUTOMATIC INTERMITTENT TRACI'IEOTOMY TUBE CUFF INFLATOR-DEFLATOR This invention relates to cycling respirators used in surgery and treatment of respiratory conditions and is directed primarily to an automatic metering system for controlling the inflation of a tracheotomy cuff used with such respirators. It is necessary in the use of cycling respirators to provide an airtight seal between the breathing tube inserted into the trachea and the walls of the trachea itself so that accurate lung pressure can be maintained at all times throughout the ventilating cycle. This is accomplished by an inflatable cuff of soft rubber which surrounds the breathing tube and is expanded to press against the trachea wall. It is essential that the pressure of the cuff against the trachea be regulated with extreme accuracy as the trachea is easily damaged. Also, where the cuff presses against the trachea wall the blood circulation in the wall is temporarily blocked and the pressure must be released periodically to allow circulation to resume before the tissue is damaged. On the other hand, if the cuff is deflated to the point where it separates from the trachea wall the breathing cycle is impaired by the escape of air and, also, there is danger of foreign matter entering the lungs if the patient vomits, or if there is foreign matter from other causes in the patients oral and nasal passages.
An object of this invention is to provide a cycled pressure change within the cuff to match the cycle of the respirator so that the cuff is inflated to a maximum, but accurately controlled volume, while the respirator is forcing air into the lungs, and deflated to a minimum volume while still maintaining contact with the trachea wall during the expiration part of the cycle, thus allowing blood circulation in the trachea wall to resume momentarily but still maintaining the closure. This result is accomplished by the attachment of an inflator-deflator to the pneumatic line running from the respirator to the nebulizer, a medication metering device always included in the system when an automatic cycling respirator is used.
The inflator-deflator consists essentially of a pneumatic cylinder with a free running piston as hereinafter described. The pressure in the pneumatic line fluctuates with the ventilating cycle and is used in connection with the invention to power the pressure cycle in the tracheotomy cuff.
Another object of the invention is to provide an instantaneous indication of the occurrence of a leak in the cuff which if not detected can have serious detrimental effects on the breathing cycle or may allow the entry of foreign matter into the lungs to the serious detriment of the patient.
Another object of the invention is to provide a safeguard against overinflation of the cuff and resulting damage to the trachea wall.
These and other objects will become apparent from the following description and the accompanying drawing, in which:
FIG. 1 is a semi-diagrammatic illustration of the complete tracheotomy system including the invention.
FIG. 2 is a longitudinal sectional view of the inflator-deflator.
FIG. 3 is a diagram showing how the breathing tube and cuff are inserted through the mouth of the patient or an endotracheal insertion.
FIG. 4 is a diagram showing how the breathing tube and cuff are inserted through an incision or tracheotomy as is sometimes necessary.
FIG. 5 is a detailed vertical sectional view of the cuff and the breathing tube in place in the trachea.
As illustrated in FIG. 1 the system includes a respirator which automatically controls the breathing cycle, a main breathing tube 11 which carries air in and out of the lungs during surgery or treatment, a nebulizer 12 which adds a predetermined percentage of oxygen or medication to the air entering the lungs, and which is cycled by a pneumatic line 13 which alternates between high and low pressure in time with the respirator. A tracheal tube 14 is inserted in the patients trachea by means of a tracheotomy as shown in FIG. 4, or a similar tracheal tube 14a is inserted through the mouth as shown in FIG. 3. A soft rubber cuff l5 surrounds the tube 14 and is inflated by air pressure through a pneumatic line 16.
An inflator-deflator 17 is attached to the pneumatic line 13 by a branch line 18 connected at a T-joint l9, and is thus supplied with the pulsating air pressure fed into the line 13 by the respirator 10.
As shown in FIG. 2, the inflator-deflator l7-includes a transparent plastic cylinder 20 having a screw cap 21 from which extends a slide 22 ending in a bearing 23. The opposite end of the cylinder 20 is conical in shape with a center outlet 24 to the pneumatic line 16. A rubber piston 25 with integrally molded sealing rings 26 has one conical face 27 which will completely seal the center outlet 24 if the piston is forced against it. The piston 26 is attached to one end of a rod 28 which extends through the cap 21 and the bearing 23 and is supplied with an external handle 29. A stop 30 slidably attached to the rod 28 can be fixed in any position by a thumbscrew 31. A bleed off port 32, by means of which the rod 28 penetrates the cap 21, is accurately sized to allow the escape of exhaust low pressure air when the piston 25 moves towards the cap end of the cylinder 20 but holds sufficient high pressure air to move the piston 25 away from the cap end when high pressure air is fed through the branch line 18.
After the trachea tube 14 is inserted with the cuff 15 in its deflated condition, as shown by the dotted line 15a, and while the piston 25 is in the retracted position as shown by the dotted line 25a, the respirator is cycled until the high pressure builds up in the branch line 18. This moves the piston 25 forward to the position indicated by the dotted line 25b. The entrapped air ahead of the piston 25 inflates the cuff 15, as detailed in FIG. 5, making a tight seal between the wall of the trachea 33 and the breathing tube 14. The bleed off port 32 is matched to the characteristics of the respirator 10 so that optimum pressure is supplied to the cuff 15.
As the respirator 10 cycles, the pressure drops in the branch line 18 and the piston 25 retracts to a position shown by the dotted line 250. The elastic cuff l5 relaxes to the position indicated by the dotted line 15b which is just sufficient to maintain contact with the trachea wall 33, but allows the blood to circulate in the area of contact. The stop 30 is set on the rod 28 at such a point that it now bears against the bearing 23 as shown by the dotted line 30c.
The transparent cylinder 20 is calibrated on the outside as with marks 34 and the position of the piston 25 can be read at all times by the attendant. Should the cuff l5 spring a leak, the piston will either not return all the way to its position 25c or it will move over towards the outlet 24. Should the respirator 10, because of malfunction, introduce an unsafe pressure behind the piston 25, the latter will move over and seal the outlet 24, preventing excessive pressure build up in the cuff 15. In either case the condition will be immediately apparent to the attendant and the machine can be turned off. This malfunction indication is one of the most valuable features of the invention. Another valuable feature is that its operation is completely automatic once the cycle is started and adjusted.
Respirators used without the addition of this invention have required constant manipulation and adjustment by an expert operator and, while the present invention does not eliminate the necessity of supervision by a trained attendant, it substantually reduces the chance of error and of serious injury to the patient.
The invention is not limited to the exemplary construction herein shown and described, but may be made in various ways within the scope of the appended claims.
1. An inflator-deflator for the tracheal cuff for an automatic cycling respirator system which includes a cycling respirator, a nebulizer and trachea tube with conventional pneumatic connections comprising an air cylinder connected at one end to a branch of the pulsating pneumatic control line running from the respirator to the nebulizer, a piston within said cylinder attached to a rod extending beyond that end of said cylinder to which the control line is attached, an outlet on the opposite end of said cylinder which is closed when said piston is pressed against it, a pneumatic tube leading from said outlet to the trachea cuff of said respirator system, a closure on the rod end piston rod and including alstop adjustably secured to said piston rod.
3. An inflator-deflator for the trachea cuff for automatic cycling respirator system as described in claim 2, in which the said piston rod runs in an aligning bearing at theouter end of said slide means and is equipped with a handle for manual location of the piston within the cylinder.