Method and apparatus for the continuous monitoring of hemoglobin saturation in the blood of premature infants

• US 4,485,820 A
• Filed: 05/10/1982
• Issued: 12/04/1984
• Est. Priority Date: 05/10/1982
• Status: Expired due to Fees

• Current Assignee: Johns Hopkins University
• Original Assignee: Johns Hopkins University
• Inventors: Flower, Robert W.
• Primary Examiner(s): Howell, Kyle L.
• Assistant Examiner(s): Hanley, John C.
• Application Number:
  US06/376,784
• Time in Patent Office: 939 Days
• Field of Search: 128/633, 128/634, 128/745, 128/664-666, 356/41, 351/219
• US Class Current: 600/320
• CPC Class Codes: A61B 3/10 Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
• CPC Class Codes: A61B 5/14555 specially adapted for the eye fundus

Abstract

A method and apparatus is disclosed for continuously monitoring hemoglobin saturation in the blood of premature infants. A substantial portion of the eye fundus is illuminated by passing at least two frequencies of light through the pupillary opening. The light scattered from the fundus is collected as it passes out through the pupillary opening and its intensity is measured. Calculations known in the art are used to determine blood hemoglobin based on the intensity of the scattered light. A contact lens with associated fiber optic links is used to illuminate the infant eye and to collect the scattered light.

Claims

1. An oximeter for continuous non-invasive monitoring of hemoglobin saturation levels in premature infants, comprising:

an opaque contact means, having a concave surface adapted to fit over the globe of a patent'"'"'s eye, for mounting on the eye in communication with the outer surface of the eye cornea said contact means further having a plurality of holes therethrough with openings on the concave surface;

a light source capable of providing light at various frequencies;

at least one transmitting fiberoptic element means mounted into one of said holes, linking said contact means to said light source, for illuminating a substantial portion of the eye fundus;

at least one receiving fiberoptic element means mounted into one of said holes and terminating a predetermined distance from the concave surface of said contact means for collecting light scattered by a substantial portion of said eye fundus and for reducing the collection of cross-talk light from said at least one transmitting fiberoptic element means and light from said at least one transmitting fiberoptic element means which is backscattered by the cornea; and

,

a detector, processor and indicator circuit means, linked by said receiving fiberoptic element to said contact means, for measuring the intensity of light radiation scattered by said eye fundus and for calculating and indicating hemoglobin saturation based upon the intensity of said scattered light for various frequencies of said illuminating light.

3. The apparatus of claim 1 wherein a plurality of said at least one illuminating fiberoptic element means are mounted in an annular array of holes in said contact means;

and, wherein said annular array encircles said receiving fiberoptic element means.

4. The apparatus of claim 1 wherein a plurality of said at least one receiving fiberoptic element means are mounted in an annular array of holes in said contact means;

and, wherein said annular array encircles said illuminating fiberoptic element means.

5. The apparatus of claim 3 or 4 wherein said annular array is a continuous annulus.

2. The apparatus of claim 13 wherein said contact means is adapted to fit over at least a portion of the eye sclera.

6. An oximeter for continuous non-invasive monitoring of hemoglobin saturation levels in premature infants, comprising:

an opaque contact means, having a concave surface adapted to fit over the globe of a patient'"'"'s eye, for mounting on the eye in communication with the outer surface of the eye cornea said contact means further having a plurality of holes therethrough with openings on the concave surface;

a light source capable of providing light at various frequencies;

at least one transmitting fiberoptic element means mounted into one of said holes and, terminating a predetermined distance from the concave surface of said contact means, linking said contact means to said light source, for illuminating a substantial portion of the eye fundus;

at least one receiving fiberoptic element means mounted into one of said holes and, terminating a predetermined distance from the concave surface of said contact means for collecting light scattered by a substantial portion of said eye fundus and for reducing the collection of cross-talk light from said at least one transmitting fiberoptic element means and light from said at least one transmitting fiberoptic element means which is backscattered by the cornea; and

,

a detector, processor and indicator circuit means, linked by said at least one receiving fiberoptic element means to said contact means, for measuring the intensity of light radiation scattered by said eye fundus and for calculating and indicating hemoglobin saturation based upon the intensity of said scattered light for various frequencies of said illuminating light.