Hypodermic anesthetic injection apparatus and method

• US 5,180,371 A
• Filed: 02/08/1991
• Issued: 01/19/1993
• Est. Priority Date: 05/30/1986
• Status: Expired due to Term

• Current Assignee: Milestone Scientific Incorporated
• Original Assignee: Spintech, Inc.
• Inventors: Spinello, Ronald P.
• Primary Examiner(s): Hirsch, Paul J.
• Application Number:
  US07/652,495
• Time in Patent Office: 711 Days
• Field of Search: 604/131, 604/152, 604/154, 604/155, 604/156, 604/118, 604/905, 604/229, 604/207, 604/228, 604/51, 604/20, 128/DIG. 1, 128/665, 433/84, 433/85, 433/89, 433/90, 433/112
• US Class Current: 604/118
• CPC Class Codes: A61C 19/08 combined with anaesthetising implements dental hypodermic syringes A61M5/00
• CPC Class Codes: A61M 2202/048 Anaesthetics see also A61M19/00
• CPC Class Codes: A61M 5/14546 Front-loading type injectors
• CPC Class Codes: A61M 5/20 Automatic syringes, e.g. with automatically actuated piston rod, with automatic needle injection, filling automatically A61M5/142 , A61M5/46 take precedence; hypodermic projectiles F42B12/54
• CPC Class Codes: A61M 5/2053 Media being expelled from injector by pressurised fluid or vacuum for infusion A61M5/145, A61M5/155
• CPC Class Codes: A61M 5/24 Ampoule syringes, i.e. syringes with needle for use in combination with replaceable ampoules or carpules, e.g. automatic ampoules or carpules A61J1/06
• CPC Class Codes: A61M 5/3129 Syringe barrels A61M5/3205 and A61M5/50 take precedence
• CPC Class Codes: A61M 5/3148 Means for causing or aiding aspiration or plunger retraction
• CPC Class Codes: A61M 5/422 Desensitising skin

Abstract

An aspirating hypodermic syringe and method for injecting dental anesthetic in which anesthetic flow through the needle is established independently of the fingers of the operator and in which different rates of flow are provided, including positive flow while the needle is entering the tissue. Effective aspiration in syringes which use expendable anesthetic vials is assured by means of a yieldable resistance member in the syringe which holds the vial with sufficient force to enable the syringe plunger to lock positively onto the piston of the vial.

Claims

1. Apparatus for the injection of anesthetics including a hollow hypodermic needle, a handle assembly for carrying the needle, and a single source of liquid anesthetic, the apparatus comprising:

pump means having a positive duty cycle to expel liquid anesthetic from the needle tip,

programmed discharge flow rate control means associated with the positive duty cycle to selectively expel liquid anesthetic at a first rate not to exceed 0.25 to 1.0 cc. per minute and at a second rate of greater than approximately 2.0 cc. per minute,

and control means to select between the first and second flow rates, whereby the first flow rate can be established during implantation of the needle in the tissue to establish a small positive low flow rate during penetration, and the second flow rate can be established after implantation.

2. Apparatus as set forth in claim 1, said pump means being remote from the handle assembly and connected thereto by a flexible conduit.

3. Apparatus as set forth in claim 1 in which the second injection rate is between 2 and 4 cc. per minute.

4. Apparatus as set forth in claim 1 including means to interpose a negative duty cycle to aspirate after a predetermined amount of liquid anesthetic has been expelled from the needle tip whereby liquid anesthetic can be expelled from the needle tip at a rate not to exceed 0.25 to 1.0 cc. per minute as the needle is advanced into the tissue toward its ultimate resting place to anesthetize both the route of needle penetration and the ultimate site of subsequent anesthetization prior to expelling the anesthetic at the second rate.

5. Apparatus as set forth in claim 2 in which the second rate is on the order of 2 to 4 cc. per minute.

6. Apparatus as set forth in claim 4 including means for controlling the rate and duty cycle from a point remote from the handle assembly.

7. Apparatus as set forth in claim 6 including foot controlled switch means for activating and controlling said pump means.