Note: Descriptions are shown in the official language in which they were submitted.
5 7. ~
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
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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.
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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:
