Air-in-tip jet injector
First Claim
1. A method for injecting a fluid medicament into a patient which comprises the steps of:
- holding said fluid medicament in a chamber, said chamber having a port for ejecting said fluid medicament therethrough;
creating a pocket of gas in said chamber, said pocket of gas being located in said chamber contiguous to said port;
positioning said port against the patient; and
thereafter forcing said gas and said fluid medicament through said port for injection of said fluid medicament into the patient.
3 Assignments
0 Petitions
Accused Products
Abstract
A method for injecting a fluid medicament into a patient uses a syringe having a plunger that can be advanced into the syringe chamber. As the plunger is advanced, the medicament is expelled from the chamber through an injection tube that extends from the chamber. Preferably, the injection tube is formed as a cone-shaped funnel with a taper of generally decreasing radius in a distal direction. The steps for the method include creating a gas pocket in the distal portion of the injection tube. Then, as the plunger is advanced into the chamber to accelerate the fluid medicament through the injection tube, the gas pocket allows the accelerating fluid medicament to gain momentum. The change in this momentum as the fluid medicament collides with the skin will generate an impulse force that is manifested as an initial pressure spike. This pressure spike creates a hole in the skin of the patient as the fluid medicament exits the tube. Further advancement of the plunger into the chamber maintains a substantially constant infusion pressure for injecting the fluid medicament through the hole and into the patient.
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Citations
16 Claims
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1. A method for injecting a fluid medicament into a patient which comprises the steps of:
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holding said fluid medicament in a chamber, said chamber having a port for ejecting said fluid medicament therethrough;
creating a pocket of gas in said chamber, said pocket of gas being located in said chamber contiguous to said port;
positioning said port against the patient; and
thereafterforcing said gas and said fluid medicament through said port for injection of said fluid medicament into the patient. - View Dependent Claims (2, 3, 4, 5, 6, 7)
accelerating said fluid medicament through said pocket of gas and said tube, said tube having an empty distal portion for generating an initial pressure spike during transit of said fluid medicament through said distal portion, said pressure spike having a first pressure for creating a hole in the skin of the patient as said fluid medicament exits said tube; and
maintaining a substantially constant infusion pressure for injecting said fluid medicament through the hole into the patient, said first pressure being greater than said infusion pressure.
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5. A method as recited in claim 1 wherein said chamber is a component of a syringe, wherein said syringe includes a plunger and said plunger is positioned for advancement into said chamber and, alternatively, for withdrawal from said chamber, and wherein said forcing step is accomplished by advancing said plunger into said chamber to expel said fluid medicament therefrom.
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6. A method as recited in claim 5 further comprising the step of withdrawing said plunger from said chamber to create said pocket of gas.
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7. A method as recited in claim 1 wherein said pocket of gas has a fluid volume in a range between one and twenty microliters (1-20 μ
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8. A method for injecting a fluid medicament into a patient which comprises the steps of:
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providing a chamber containing a fluid medicament;
extending an injection tube from said chamber, said injection tube being in fluid communication with said chamber, and said injection tube having a distal portion filled with a pocket of gas with said fluid medicament proximal thereto; and
forcing said gas and said fluid medicament from said chamber and through said injection tube to inject said fluid medicament into the patient by accelerating said fluid medicament through said distal portion of said injection tube to generate an initial pressure spike during transit of said fluid medicament through said distal portion, said pressure spike having a first pressure for creating a hole in the skin of the patient as said fluid medicament exits said tube, and maintaining a substantially constant infusion pressure for injecting said fluid medicament through the hole into the patient, said first pressure being greater than said infusion pressure. - View Dependent Claims (9, 10, 11, 12)
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13. A method for injecting a fluid medicament into a patient which comprises the steps of:
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accelerating a fluid medicament through a tube, said tube having an empty distal portion for generating an initial pressure spike during transit of said fluid medicament through said distal portion, said pressure spike having a first pressure for creating a hole in the skin of the patient as said fluid medicament exits said tube; and
maintaining a substantially constant infusion pressure for injecting said fluid medicament through the hole into the patient, said first pressure being greater than said infusion pressure. - View Dependent Claims (14, 15, 16)
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Specification