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Improved Tidal Aerosol Dru~ Svstem Requirinq Assisted Respiration Field of the Invention The present invention relates to drug aerosol systems used in treatment of patients requiring assisted ventilation with the aid of a respirator.
Backqround of the Invention Current treatment of patients with a drug in small particle aerosol during periods when they require assisted respiration requires the introduction of the drug aerosol in a volume approximating the tidal volume of the patient. When respiration is initiated by the respirator, the drug aerosol is carried into the patient's lungs where a large portion of it is deposited. At the present time, plastic tubing (22 mm, i.d.) is used which is widely available in hospitals for supplying gases to patients and requires about 8-12 feet (two or three 4 foot sections) between the adult patient and the site of inflow of drug aerosol to provide a volume of aerosol equal to the patient's tidal volume. This is inconvenient, is difficult to manage, and permits deposition of the drug on the wall of the tubing thereby losing it from the aerosol. Because of their small tidal volumes, infants do not require the present invention.
Description of the Prior Art U~S. Patent No. 4,649,911 discloses a small particle aerosol or nebulizer apparatus effective for providing small particle aerosols containing drug effective for treating the respiratory tract and lungs. A detailed statement of the prior art is set forth in this patent.
U.S. Patent No. 4,211,711 is directed to the drug, ribavirin, usual in treating of lung disease, such as respiratory syncytial and influenza virus infections.
Summary of the Invention The present invention is directed to a drug aerosol system for treatment of patients requiring assisted respiration by which a tidal volume or more of the drug aerosol to he inhaled is provided to the patient w~ich is convenient to use, easy to manage, and in which the drug is not lost to the wall of the tubing. In short, this is accomplished by providing a chamber large enough in volume to accommodate a large tidal volume in the flow line leading to the patient, thus allowing a shortening of the inflow tubing to a short distance from each end of the chamber, for example, a few inches. This makes treatment of patients with drug aerosol more convenient, easy to manage and much less prone to disruption or loss of drug to the patient in use.
Accordingly, it is an object of the present invention to provide a drug aerosol system for patients requiring assisted respiration which is convenient, easy to manage, much less prone to disruption, and in which drug is not lost but delivered to the patient.
It is a further obiect of the present invention to provide an aerosol treatment system for patients requiring assisted respiration by providing a chamber large enough in volume to accommodate a large tidal volume thereby considerably shortening the tubing required in such treatment and which is convenient and is easy to manage, less prone to disruption than current systems in use, and in which drug is not lost from the aerosol but delivered to the patient.
Other and further objects, features, and advantages appear throughout the specification and claims and are inherent in the present invention.
Brief Description of the Drawinqs Figure 1 is a schematic diagram of an aerosol generator respirator system for providing a tidal volume of drug aerosol to a patient currently in use.
Figure 2 is a schematic diagram of an aerosol generator respirator system for providing a tidal volume to a patient according to the invention.
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Description of Preferred Embodiments Referring now to Figure 1, a conventional drug aerosol system for a patient requiring assisted ventilation by a respirator is illustrated and is indicated by the reference numeral 10. The system 10 includes an aerosol generator 12 a respirator 14, a first flow passage, here made up of tubing segments 14 and 16, to the patient 18 and a second flow passage 20 which is connected to and in fluid communication with the first flow passage segments 14 and 16 and extends to and is in fluid communication with the respirator 14. The first flow passage segment 16 is connected to the endotracheal catheter 22 in the mouth of the patient 18. A third flow or return line 24 with the filter 26 is connected to the endotracheal catheter 22 and to the respirator 14 to receive the exhalation from the patient 18. For convenience, a "T" connection 15 as illustrated or other suitable connection such as a "Y" connection, not shown, connects the flow lines 14, 16 and 20, and a one-way valve 17 is provided which prevents backflow into the aerosol generator 12.
In order to provide a full tidal volume of a drug in small particle aerosol to the patient 18 in the conventional system 10, the first flow line having the segments 14 and 16 are of plastic tubing 22 mm, id, which is widely available in hospitals for supplying gas to patients and requires about 8-12 feet of accordion tubing (two or three 4 foot sections) 16 between the adult patient 18 and the point of inflow of drug aerosol to provide a tidal volume of aerosol. This is inconvenient, bulky, difficult to manage, prone to disruption, and drug is lost from the aerosol on the inner walls of the tubing, and hence does not get to the patient 18.
Referring now to Figure 2, a system according to the invention for providing a tidal volume of drug in small particle aerosol is illustrated. The same reference numerals with the letter "a" are used in Figure 2 to designate like parts of Figure 1 for convenience of reference. In Figure 2, a drying chamber 19 is inserted in the first flow line segments 16a. The actual volume of the chamber 19 is not critical only in that it should be large enough in volume to accommodate a large tidal volume. A
volume of 1.5 liters will accommodate almost any foreseeable tidal volume. Any excessive tidal volume will cause no harmful effects and a slight deficiency of volume, should it occur, will be of little consequence. Preferably, the drying chamber 19 is made of a rigid, transparent plastic material. This allows shortening of the segment 16a to a few inches at each end of the chamber. This provides a compact and easily manageable aerosol delivery system which prevents deposition of drugs on the wall of the tubing, and thus reduces drug from being lost from the aerosol delivered to the patient 18.
The flow passages may be made of any flexible tubing, for example accordion plastic tubing (22 mm, id) that is widely available in hospitals for supplying gases to patients.
The aerosol generator 12a, the respirator 14a, the "Tl' connection 15a or other suitable connection, such as a "Y," the one-way valve 17a, and the flow filter 26a are conventional and are readily available on the market. For example, the aerosol generator can be of the type illustrated in U.S. Patent NoO
4,649,911. Also, two commercially available nebullzers are the Puritan Bennett nebulizers Model No. 1920 and Model No. 1917.
Any aerosol generator or nebulizer can be used which generates small particle aerosols containing drugs of a size which will be deposited in the lung. For example, 1.5 micron particles will deposit 46% of the total inhaled dose in the lung and another 36%
in the nose and upper air passages.
The respirator may be any conventional respirator, many of which are readily available on the market, such as the IMV
bird, the Bird Ventilator with Demand CPAP or the Sechrist IV-100 .
Accordingly, no more description of the aerosol generator, respirator, "Y" or "T" connections, one-way valve filter and endotracheal tube is given or deemed necessary.
In use, it is important that one tidal volume be available when the patient breathes. Many adult patients have 700-800 ml of tidal volume. With the endotracheal tube 22a in place in the trachea and held in place and air tight, the respirator 14a being set to deliver a tidal volume (a single breath) a specified number of times per minute, the drug aerosol is forced into the lung of the patient 18a with pressure generated by the respirator through an endotracheal tube and actually inflates the lungs. When the patient 18a exhales through the third flow passage 24a, a full tidal volume or even more than a tidal volume of aerosol enters the chamber 19 thereby providing a full tidal volume or more thereby insuring an adequate dose to the patient 18a during the inspiratory phase.
The one-way valve 15a prevents any back flow into the aerosol generator 12a.
The drug aerosol system of the present invention can be used to administer any drug into the lung of a patient requiring assisted respiration. For example, ribavirin, pentamidine, insulin, cyclosporin A, other antiviral drugs and many other medications may be so administered. As previously mentioned, because of their small tidal volumes, this system is not required for treatment of infants.
Accordingly, the present invention is well suited and adapted to attain the objects and ends and has the features and advantages mentioned as well as others inherent therein.
While presently preferred embodiments of the invention have been given for the purpose of disclosure, changes can be made therein which are within the spirit of the invention as defined by the appended claims.
WHAT IS CLAIMED IS: