Method to sense the tissue for injection from a hypodermic needle
First Claim
1. A method for identifying which of a plurality of subcutaneous tissue types a needle has penetrated at a target location through the outer surface of a body, comprising:
- placing a reference electrode on the surface of the body at a reference location spaced from the target location;
applying an electrical source signal to one of the reference electrode and the needle with an electrical signal source means;
connecting electrical signal processing means to the reference electrode and to the needle, said signal processing means including means for sensing the impedance encountered by said source signal in passing between the needle and the reference electrode;
inserting the needle into the body at the target location while monitoring the sensed impedance; and
in response to variations in the impedance during the step of inserting the needle, generating an output signal indicative of the type of subcutaneous tissue into which the needle has penetrated.
0 Assignments
0 Petitions
Accused Products
Abstract
Many pharmaceuticals require a specific tissue for injection, such as adipose or muscle, to optimize the effect of the drug. This is important to achieve the desired bioavailability of the injected substance. In some cases, intravenous injections are desired over subcutaneous and intramuscular. The invention is a bioimpedance method and apparatus for sensing a hypodermic needle'"'"'s transition from subcutaneous adipose to muscle tissue. The invention could also be used to sense a vascular transition. The sensing can be integrated into instrumentation that identifies the tissue or simply signals that the transition has occurred. The physician or nurse could then confidently inject the medication into the intended tissue.
90 Citations
17 Claims
-
1. A method for identifying which of a plurality of subcutaneous tissue types a needle has penetrated at a target location through the outer surface of a body, comprising:
-
placing a reference electrode on the surface of the body at a reference location spaced from the target location; applying an electrical source signal to one of the reference electrode and the needle with an electrical signal source means; connecting electrical signal processing means to the reference electrode and to the needle, said signal processing means including means for sensing the impedance encountered by said source signal in passing between the needle and the reference electrode; inserting the needle into the body at the target location while monitoring the sensed impedance; and in response to variations in the impedance during the step of inserting the needle, generating an output signal indicative of the type of subcutaneous tissue into which the needle has penetrated. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A method for injecting a substance through a syringe needle into a preselected one of a plurality of subcutaneous tissue types beneath a target location on a body surface, comprising:
-
placing a reference electrode of the surface of the body at a reference location spaced from the target location; applying an electrical source signal to one of the reference electrode and the needle with an electrical signal source means; connecting electrical signal processing means to the reference electrode and to the signal source means, said processing means including means for sensing the impedance encountered by said source signal in passing between the needle and the reference electrode; inserting the needle into the body at the target location while monitoring the sensed impedance; in response to variations in the impedance during the step of inserting the needle, generating an output signal indicative of the type of subcutaneous tissue into which the needle has penetrated; and injecting the substance when the needle is in the preselected subcutaneous tissue as indicated by the output signal. - View Dependent Claims (8, 9, 10, 11, 12)
-
-
13. Apparatus for identifying which of a plurality of subcutaneous tissue types a needle has penetrated at a target location through the outer surface of a body, comprising:
-
a reference electrode for placement on the surface of the body; source means connectable to a syringe needle, for applying an electrical source signal to the needle; electrical signal processing means connected to the reference electrode and to the means for applying a source signal, said processing means including means for sensing the impedance encountered by said source signal in passing between the needle and the reference electrode; means responsive to variations in the sensed impedance for generating an output signal indicative of the type of subcutaneous tissue into which the needle has penetrated. - View Dependent Claims (14, 15, 16, 17)
-
Specification