Sensor having cutaneous conformance

• US 4,830,014 A
• Filed: 07/07/1987
• Issued: 05/16/1989
• Est. Priority Date: 05/11/1983
• Status: Expired due to Term

• Current Assignee: Nellcor Puritan Bennett Incorporated (Medtronic Plc)
• Original Assignee: Nellcor Incorporated (Medtronic Plc)
• Inventors: Yelderman, Mark, New, William Jr., Goodman, David E., Corenman, James E.
• Primary Examiner(s): Coven, Edward M.
• Application Number:
  US07/070,619
• Time in Patent Office: 679 Days
• Field of Search: 128/633, 128/637, 128/640, 128/644, 128/665, 128/667, 128/664, 128/689, 128/690, 128/691
• US Class Current: 600/310
• CPC Class Codes: A61B 5/02427 Details of sensor
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/6819 Nose
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips

Abstract

A sensor for trans-illumination of a blood perfused portion of flesh to measure light extinction during trans-illumination is disclosed. The sensor is preferably mounted on a fingertip but any digit or blood perfused portion of flesh will work. The sensor includes a first end for disposition on one side of the trans-illuminated flesh and a second end for disposition on the opposite and opposed side of the trans-illuminated flesh. A light source is mounted to the first side and a photo-sensor is mounted to the second side. If an elongated flexible strip is used, it is provided with adhesive and is suitably windowed that light is allowed to take an optical path through the finger. If no flexible strip is used, the two ends are aligned and secured to the flesh such that the light emitted takes an optical path through the finger. When the adhesive fastener is used, the effect of the light source and photo-detector substrates being integrated into the adhesive fastener is that they become, in effect, a part of the skin. The resulting device is resistant to accidental removal and avoids constriction of blood vessels. Most importantly, the low mass of the sensor itself and its conformance to, so as to effectively become a part of, the skin, prevents relative motion between the light source and sensor and the perfused flesh. This eliminates the common interference associated with the operation of conventional plethysmographs and oximeters.

Claims

1. A non-invasive, electrooptical sensor probe for removable adhesive attachment to a convex portion of the skin of a patient for use in measuring light extinction during transillumination of the blood-perfused tissue beneath said skin comprising:

a flexible, initially substantially planar, web-like support structure having substantially parallel, spaced, oppositely facing upper and lower surfaces;

a light source mounted in the web of said support structure, said light source having a light-emitting surface facing in the same direction as said lower surface;

a photo-sensor mounted in the web of said support structure, said photo-sensor having a light-responsive surface facing in the same direction as said lower surface, said photo-sensor being spaced from said light source in the plane of said support structure; and

an adhesive layer on said lower surface for removably adhesively securing said lower surface to said convex portion of said skin so that said lower surface is held in conformance with said skin, said support structure being flexible also to conform to said skin without stressing either of said skin and the underlying tissue at any time during operation of said sensor probe, the convexity of said skin portion between the locations of said light source and said photo-sensor causing said light-emitting and light-responsive surfaces to be inclined toward one another so that light from said light source transilluminates the tissue between said light source and said photo-sensor and said light-responsive surface receives at least a part of said light.

2. The apparatus defined in claim 1 wherein said support structure comprises:

a lower layer which is relatively opaque except at the locations of said light source and photo-sensor, where said lower layer is relatively transparent;

an upper layer; and

means for adhesively securing said upper and lower layers together with said light source and photo-sensor captured therebetween.