Physiological sensor having reduced sensitivity to interference

• US 9,226,712 B2
• Filed: 09/19/2013
• Issued: 01/05/2016
• Est. Priority Date: 05/26/2009
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Gonopolskiy, Oleg, Anderson, Arik
• Primary Examiner(s): Hannaher, Constantine
• Application Number:
  US14/031,884
• Publication Number:
  US 20140121484A1
• Time in Patent Office: 838 Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2562/182 Electrical shielding, e.g. using a Faraday cage
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/68335 including release sheets or liners
• CPC Class Codes: A61B 5/7217 of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker

Abstract

A physiological sensor having reduced sensitivity to interference includes a light source, a light detector in optical communication with the light source, and a sensor pad at least partially housing the light source and the light detector. The sensor pad is configured to be capacitively isolated from a patient. Moreover, the physiological sensor may be electrically connected to an amplifier having a signal ground and a monitor.

Claims

1. A sensor comprising:

a sensor pad having a first surface configured to be affixed to a patient and a second surface that is opposite said first surface;

a light source configured to generate light and a light detector configured to receive light generated by the light source, said light source and said light detector being associated with said sensor pad; and

a conductive material disposed on said second surface of said sensor pad such that said sensor pad is capacitively isolated from the patient.

2. The sensor of claim 1, wherein a capacitance of the conductive material relative to the patient is inversely proportional to a distance between the conductive material and the patient and the distance is based on the thickness of the sensor pad.

3. The sensor of claim 2, wherein the capacitance between the conductive material and the patient is defined as:

C_p=∈

₀∈

_r A/d, wherein C_p is the capacitance in Farads, A is an area of the sensor pad disposed on the patient, d is a distance between the conductive material and the patient, ∈

_r is a dielectric constant between the conductive material and the patient, and ∈

₀ is a permittivity of free space.

4. The sensor of claim 3, wherein the dielectric constant between the conductive material and the patient is greater than 1.

5. The sensor of claim 1, wherein the conductive material is a conductive adhesive.

6. A system comprising:

an amplifier configured to receive signals representing physiological information, wherein the amplifier includes a monitor configured to graphically display the physiological information represented by the received signals; and

a sensor communicatively coupled to said amplifier, comprising;

a sensor pad having first surface configured to be affixed to a patient and a second surface that is opposite said first surface;

a light source configured to generate light and a light detector configured to receive light generated by the light source, said light source and said light detector being associated with said sensor pad; and

a conductive material disposed on said second surface of said sensor pad.

7. The system of claim 6, wherein a capacitance of the conductive material relative to the patient is inversely proportional to a distance between the conductive material and the patient and the distance is based on the thickness of the sensor pad.

8. The system of claim 7, wherein the capacitance between the conductive material and the patient is defined as:

C_p=∈

₀∈

_r A/d, wherein C_p is the capacitance in Farads, A is an area of the sensor pad disposed on the patient, d is a distance between the conductive material and the patient, ∈

_r is a dielectric constant between the conductive material and the patient, and ∈

₀ is a permittivity of free space.

9. The system of claim 6, wherein the sensor pad is capacitively isolated from the monitor.

10. The system of claim 6, wherein the sensor pad has a thickness that capacitively isolates the conductive material from the patient.

11. A sensor comprising:

a sensor pad having a second surface configured to be affixed to a patient and a first surface that is opposite said second surface;

a light source configured to generate light and a light detector configured to receive light generated by the light source, said light source and said light detector being associated with said sensor pad; and

a conductive material that covers substantially all of said first surface of said sensor pad.

12. The sensor of claim 11, wherein said conductive material is a conductive adhesive.

13. The sensor of claim 11, wherein said conductive material is a coatable material.

14. A sensor comprising:

a sensor pad having a second surface configured to be affixed to a patient and a first surface that is opposite said second surface;

a light source configured to generate light and a light detector configured to receive light generated by the light source, said light source and said light detector being associated with said sensor pad; and

a coatable conductive adhesive material disposed on said first surface of said sensor pad.