Surgery – Respiratory method or device – Means for mixing treating agent with respiratory gas
Reexamination Certificate
1998-08-04
2001-01-23
Lewis, Aaron J. (Department: 3761)
Surgery
Respiratory method or device
Means for mixing treating agent with respiratory gas
C128S205240
Reexamination Certificate
active
06176237
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to inhalation therapy units and especially to a valve for limiting the inspiration flow.
An aerosol atomizer is known from the EP-B-0 281 650, which consists of a substantially cylindrical basic body in which an atomizer nozzle is disposed for the generation of an aerosol and into which an air intake flue projects for the supply of ambient air. The outer opening of the air intake flue is closed by an inlet valve which is constructed as one-way valve. It permits the inflow of ambient air into the nebuliser housing when the patient inspires through a mouthpiece of the aerosol atomizer, but prevents the escape of the aerosol from the atomizer interior during the breathing intervals and for the event that the patent exhales into the aerosol atomizer. The known inhalation therapy unit is therefore constructed in such a manner that the patient can inspire an arbitrary volume of respiratory air, limited merely by the flow resistance defined by the shape of the atomizer.
However, the aim of an inhalation therapy is always the effective, low side-effect application of the medicine administered in aerosol form into the diseased lung regions. In this respect, an aerosol is generated in an inhalation therapy unit with a suitable droplet spectrum and in a suitable amount. This aerosol should be inhaled by the patient according to a defined breathing pattern, so that the aerosol droplets reach the desired deposition location in the lungs. Until now, it was necessary to train the patient with a view to this breathing pattern and an optimization of the breathing parameters, which in many cases led to considerable difficulties.
In these efforts, there are two contradictory requirements. On the one hand, namely, the inspiring of the aerosol should be as easy as possible for the patient, and on the other hand, a maximization of the effect of the inhalation therapy only occurs when an aerosol is inspired in such a manner that a deposition takes place at the desired location of the lungs. This procedure is influenced by the droplet size, the amount of aerosol, the amount of intake air, the inspiration flow and other parameters. With respect to the inspiration flow, until now it was only endeavoured to achieve a limitation in the inspiration path of the inhalation therapy unit by cross-section reductions (stenoses). Due to the increased flow resistance in the flow region to be realized, however, this frequently results in the encumbrance of the already weakened respiratory capacity of the patient.
An inspiration flow of up to a maximum of 30 l/min is aerosol-physically desirable in order to minimize the inertial separation, the so-called impaction, of the aerosol droplets in the upper respiratory paths and to increase the deposition probability in the lungs in the intended deposition location.
The expiratory process is of lesser significance. However, also during expiration the expiration flow should be within a certain range.
With this background, the object of the invention is to construct an inhalation therapy unit in such a manner that the maintenance of the aerosol-physically desirable ranges is simplified for the patient during respiration, without an additional encumbrance occurring for the patient upon respiration in these ranges.
SUMMARY OF THE INVENTION
This object is solved by an inhalation therapy unit comprising a nebulisation chamber in which an aerosol is generated with the aid of an atomizer nozzle, a connecting piece via which the aerosol is led out of the nebulisation chamber, an air inlet means through which the ambient air enters into the nebulisation chamber, and an inlet valve which includes at least one inlet opening and a valve member closing the inlet opening and which is arranged in the air inlet means in such a manner that an underpressure in the nebulisation chamber moves the valve member to release the inlet opening, a limiting member being provided in the inlet valve, which limits the movement of the valve member in such a manner that the release of the inlet opening is substantially proportional to the underpressure only up to a threshold value of the underpressure in the nebulisation chamber.
In a special configuration of this solution, the limiting member comprises at least one passage orifice, which is partially closed by the valve member when the valve member is moved until it is against the limiting member by an underpressure exceeding the threshold value in the nebulisation chamber.
The problem on which the invention is based is further solved in general by an inhalation therapy unit with a valve, which comprises at least one through opening and a valve member which is moved on account of a pressure difference present across the valve so that it closes the through opening when the pressure difference across the valve is present in the one direction and releases the through opening when the pressure difference across the valve is present in the other direction, and a limiting member is provided that limits the movement of the valve member in such a manner that the release of the through opening is substantially proportional to the pressure difference only up to a threshold value of the pressure difference.
In a special configuration of this solution, the limiting member comprises at least one passage orifice which is partially closed by the valve member when the valve member is moved by a pressure difference exceeding the threshold value over the valve until it is against the limiting member.
In both solutions it is advantageous for the valve member to be a circular valve platelet, wherein the passage orifice of the limiting member projects at least section-wise beyond the contour of the valve platelet in the region of the outer edge of the valve platelet.
It is furthermore advantageous if the contour of the air passage orifice (
17
) of the limiting member (
16
) interacting with the valve platelet is of undulatory or zig-zag shape.
The valve member is preferably formed of silicone or another elastic material.
For use in aerosol therapy, the invention signifies that the inhalation therapy unit is equipped with a limiting valve which is adaptable to the lung-physiological parameters of the patient and controls the inspiration flow of the patient as a passive controller of the threshold value. By means of a strongly progressive pressure/flow characteristic above a certain flow threshold value, it is achieved that the patient recognizes by the flow resistance felt upon inspiration that he lies outside the aerosol-physically desirable range. He can then adapt his breathing behaviour accordingly. Within the aerosol-physically desirable range, the patient feels practically no increase of the flow resistance in comparison to an inhalation therapy unit without the passive limiting valve according to the invention.
The limiting valve described in the following in more detail on the basis of an embodiment has furthermore the advantage that it is realized in an extremely simple manner and the desired aims thus can be achieved in an economical manner.
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Knoch Martin
Waldner Robert
Wunderlich Eric
Lewis Aaron J.
Merchant & Gould P.C.
Mitchell Teena
PARI GmbH Spezialisten fur effektive Inhalation
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