1. Technical Field
This invention relates generally to medical apparatuses, and more particularly to a medical apparatus and method for delivering inhaled liquid medication through a nebulizer with controlled efficiency achieved through breath actuation of a continuous flow nebulizer.
2. Description of Related Art
Medical nebulizers deliver an aerosol form of liquid medication that can be inhaled by a patient (i.e., a person) for various pulmonary problems. They are increasingly becoming applicable to non-pulmonary patients using the respiratory mucosa as a means for systemic delivery of medications. For additional related background information, refer to U.S. Pat. Nos. 1,109,318; 2,432,946; 3,769,973; 4,174,712; 4,259,951; 4,823,784; 5,020,530; 5,062,419; 5,165,392; 5,396,883; 5,398,673; 5,427,089; 5,813,401; 5,823,179; and 5,865,171.
In most nebulizers, liquid medication is aerosolized by using a compressed gas source of air, oxygen, or a mixture of several gases to generate a flow of medication continuously. The patient inhales and exhales through a mouthpiece attached to a nebulizer with an open or valved circuit. One problem with these methods of continuous nebulization, is wasted medication during a patient""s exhalation, or pausing to cough, talk, rest, and so forth.
Also, the wasted medication is vented to the surrounding environment which can expose other people nearby, including medical personnel, visitors, family members, and patients. Another possible problem may be contamination of the nebulizer and circuit caused by the patient exhaling back through the nebulizer circuit. The continuous flow of medication either in an open or closed circuit complicates the ability to accurately regulate dosages because of waste or excessive condensation. Finally, it has been suggested that some present and future medication""s integrity may be compromised by excessive continuous nebulizing action.
Accordingly, with these considerations taken into account, there is a need for intermittent nebulization with minimal efforts provided by a patient""s breathing cycle.
The present invention solves the problem of nebulizers which deliver medication and nebulize continuously, and it decreases contamination, by using the patient""s breathing cycle to automatically control the delivery of medication to the patient. The invention is an uncomplicated key-valve control attached to a nebulizer for medication delivery to the lungs. This key-valve control attaches distally to a typical nebulizer using a typical T-piece tubing fitted on the outlet of a nebulizer, and utilizing a typical one-way valve attached proximally between the mouthpiece and T-piece tube. The key-valve control allows the compressed gas source to be diverted to a nebuilizer only during the patient""s inhalation phase with minimal breathing efforts. This invention also allows exhalation through any simple one-way valve at the mouthpiece, and not through the nebulizer, thereby decreasing possible contamination of the nebulizer.
The structure of the preferred embodiment includes two tubes combined as one unit, one outer tube with an inner ring and one smaller inner tube with an inlet hole. The inlet hole is connected to a compressed gas source utilizing a small tubing with a Y-connector at its distal end. One end of the Y-connector attaches to the nebulizer gas inlet, and the other end to the compressed gas source using a typical oxygen tubing.
A solid internal valve-key cylinder with ribbed ends spaced on the distal portion, and a valve at the other end, slides axially within the inner tubing. By this piston action, the space between the ribs of the valve-key align with the inlet hole during inhalation in order to thereby direct the compressed source flow to the nebulizer during inhalation. Also, the ribbed space moves distally during exhalation in order to thereby allow the compressed gas source to escape through the outer tubing through vents at the proximal end of the inner tubing chamber. The valve-key is held in place by a post inserted through the outer tubing at a proper distance to allow correct movement. A spring mechanism on the post pushes the valve-key back to its exhaled resting position. This internal valve-key should be fitted within the inner tubing as tightly to the least amount of tolerance for the patient to easily initiate the required piston action of the invention. This can be accomplished using current medically approved plastic polymers.
This invention thereby allows nebulization by a currently used nebulizers only when the patient is inhaling the aerosolized medication, and it prevents exhalation back through the nebulizer. This, therefore, prevents waste, reduces contamination of the nebulizer, minimizes medication exposure to others, and allows more accurate dosing of medication.
FIG. 1 is a diagram of a typical prior art apparatus to which the invention is attached;
FIG. 2 is a cross section side view of the preferred embodiment of the invention along the axis of the distal end of the T-piece shown in the condition when the patient inhales;
FIG. 3 is a cross section side view of the preferred embodiment of the invention along the axis of the distal end of the T-piece shown in the condition when the patient exhales;
FIG. 4 is an enlarged side view cut away drawing of the preferred embodiment of the main cylindrical body of the invention;
FIG. 5 is an enlarged side view of the preferred embodiment of the valve-key part that slides axially fitted within the inner portion of the small inside tube;
FIG. 6 is an enlarged side view of the preferred embodiment of the blocking post and spring that is inserted into the main cylindrical body of the invention;
FIG. 7 is a side view drawing showing the preferred way a prior art nebulizer and the invention can be attached together;
FIG. 8 is an enlarged side view cut away drawing of an alternative embodiment using only the cylindrical inner chamber of the invention;
FIG. 9 is an enlarged side view cut away drawing of a second preferred embodiment of the cylindrical inner chamber and valve-key of the invention to stop compressed gas, instead of diverting the flow, by using two rib sealed chambers, an inlet hole with tubing attached to a compressed gas source, and an outlet hole with tubing connected to the nebulizer inlet; and
FIG. 10 is a side view of another alternative embodiment that is miniaturized in order to fit within a nebulizer as part of the nebulizer.