Surgery – Liquid medicament atomizer or sprayer – Gas stream aspirating medicament from reservoir
Reexamination Certificate
2002-05-17
2004-03-09
Lewis, Aaron J. (Department: 3761)
Surgery
Liquid medicament atomizer or sprayer
Gas stream aspirating medicament from reservoir
C128S203280, C128S205150
Reexamination Certificate
active
06701915
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a device for inhaling pharmaceutical drugs by means of auxiliary positive-pressure respiration.
BACKGROUND OF THE INVENTION
During normal spontaneous human breathing, inhalation occurs as the respiratory muscles actively expand the thorax, thereby creating a pressure gradient, with the result that air is drawn in, i.e. flows into the lungs in accordance with the pressure gradient. Exhaling occurs passively in that a pressure rise takes place in the lung as the thorax is restored elastically to its default position, with the result that the consumed air is expelled from the thorax and the lungs. The mean pressure level by means of which inhalation and exhalation occur alternately corresponds to the atmospheric pressure.
Under conditions of illness or disease, e.g. in the case of asthma, small and medium-sized respiratory tracts (bronchial tubes) in the lungs can become constricted. The flow resistance in them increases, particularly during exhalation, with the result that the patient is forced to work actively by means of his muscles even during exhalation. As a consequence an additional pressure increase occurs in the thorax which can result in a complete collapse of the constricted respiratory tracts and it becomes impossible to expel air from the relevant sections of the lungs (i.e. air is trapped). Such situations often occur in the form of attacks and can be acutely life-threatening for the patient (acute asthma attack).
Devices with which the patient can inhale pharmaceutical drugs himself are known in the art. These pharmaceutical drugs are generally introduced into the respiratory tracts via the mouth as an aerosol or powder inhalant by means of a nebulizer or atomizer. An advantageous embodiment has retarding chambers, such as spacers, in which a particular volume of air is enriched with aerosol or powder inhalant before being inhaled and then is made available for inhalation. This improves the effectiveness of the inhaled pharmaceutical drugs. The disadvantage of such simple, easily portable, non-electrically operated inhalation systems that can be used by the patient himself in an emergency is that they can only be operated at atmospheric pressure. Lung sections which cannot take part in spontaneous breathing because of the above-described collapse of small respiratory tracts therefore remain inaccessible at atmospheric pressure even during emergency treatment with inhaled pharmaceutical drugs.
Respiration under positive pressure is known in the art. Such methods are applied in particular in breathing apparatus used in a non-breathable atmosphere and by divers. The disadvantage of such methods is that they are not designed for patients suffering from acute breathing difficulties and are also complex, requiring valves, tubing and also, if appropriate, as with breathing apparatus with a closed breathing circuit and diving equipment, a carbon dioxide absorber to process the exhaled air which is rich in carbon dioxide. The standard positive-pressure respiration system for treating patients with severe breathing difficulties is generally in the form of complex, fixed respirators in hospital areas designed for this purpose and proceeds either automatically (mechanical respiration without action by the patient) or in assisted mode (with action by the patient), or—if the patient is breathing spontaneously—also via CPAP (continuous positive airway pressure). Respiration can be carried out with positive pressure either continuously or intermittently. Simple, non-electrically-operated manual devices for this purpose are not known in the art.
OBJECT OF THE ART
It is the object of this invention to provide a very simple, small, portable, easily operated, integrated, self-contained device which is independent of electrical power and is suitable in particular for asthmatics and patients with other obstructive lung diseases for temporarily improving the inhalation of pharmaceutical drugs which efficiently combines the therapeutic effect of inhaled pharmaceutical drugs, the advantages of a retarding chamber and the physical effect of positive-pressure respiration for a brief period, i.e. for the limited period of acute breathing difficulties.
SUMMARY OF THE INVENTION
In accordance with the invention a very simple, small, portable, easily operated, integrated and self-contained device is provided which can comfortably be stored in a bag, e.g. a handbag. The device consists of a closed system into which the patient can exhale without a breathing air circuit being created. By contrast with the complex respirators which operated hitherto with a closed breathing circuit and at a pressure greater than atmospheric pressure, there is no need here for the valves and tubing. Similarly, no processing of the exhaled gas, e.g. in a carbon dioxide absorber, takes place, meaning that a device in accordance with the invention is limited to a few minutes of use, i.e. to the duration of the acute breathing difficulties, because of the accumulation of carbon dioxide.
The device comprises a mouthpiece which can be fully encompassed by the lips; a reservoir which has a variable volume to accommodateinhalant gas, can be connected to the mouthpiece in the direction of flow either directly or via a distributor and provides the characteristic features of a retarding chamber; an adjustable airtight closure between the mouthpiece and the reservoir; and at least one connection for the pharmaceutical drug feed in the form of an aerosol or powder inhalant to the reservoir, with the pharmaceutical drug feed being either direct or indirect via a distributor. An essential feature is that the reservoir has a variable wall to enable it to change its volume, where said wall can be expanded under the pressure of inflowing inhalant gas against a restoring force such that, as a result of the action of the restoring force, auxiliary positive-pressure respiration occurs when the inhalant gas containing the pharmaceutical drug is inhaled.
The variable wall of the reservoir can be embodied in various ways so that it is at least partially movable, for example being formed of a combination of rigid and movable sections. In accordance with a preferred embodiment the variable wall has at least one elastic wall and an elastic balloon in particular forms the reservoir.
A further variant provides for the reservoir to have at least one rigid wall section on which a distributor and/or at least one connection for the mouthpiece, the inhalant gas filler connection or the pharmaceutical drug feed are provided.
A preferred embodiment provides for a gas reservoir with a compression-proof wall containing compressed inhalant gas to be connected to the reservoir directly or indirectly via a distributor and for a reclosable valve to be configured between the gas reservoir and the reservoir. In this device the gas reservoir is filled when in transport mode, and the reservoir, which is preferably in the form of a balloon with a floppy elastic wall, is empty. In accordance with the invention the pharmaceutical drugs are inhaled by first opening the filled gas reservoir with a compression-proof wall by means of a valve, allowing oxygen or oxygen-rich air to flow into the elastic-walled reservoir. As soon as the elastic-walled reservoir is sufficiently full, the valve between the gas reservoir with a compression-proof wall and the elastic-walled reservoir can be closed again, for example by the user. This means that, as in a balloon, the pressure in the elastic-walled reservoir is slightly higher than atmospheric pressure, at between greater than 0 and approx. 30 cm water column. This is caused by the elastic wall tension of the reservoir. Pharmaceutical drugs which act on the respiratory tracts can now be introduced into the elastic-walled reservoir, which thus takes on the function of a retarding chamber, from at least one commercially available bottle for the spray inhalation of pharmaceutical drugs. The device is now ready for use and can be used by the patient.
The patient encompasses the mouthp
Hermanussen Michael
Rolli Karl-Heinz
Dubno Herbert
Lewis Aaron J.
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