Laser diode optical transducer assembly for non-invasive spectrophotometric blood oxygenation

• US 7,313,427 B2
• Filed: 03/20/2006
• Issued: 12/25/2007
• Est. Priority Date: 03/12/1999
• Status: Expired due to Fees

• Current Assignee: Edwards Lifesciences Corporation
• Original Assignee: Cas Medical Systems Incorporated (Edwards Lifesciences Corporation)
• Inventors: Benni, Paul
• Primary Examiner(s): Winakur, Eric F
• Application Number:
  US11/384,615
• Publication Number:
  US 20060195024A1
• Time in Patent Office: 645 Days
• Field of Search: 600/310, 600/322, 600/323, 600/340, 600/344
• US Class Current: 600/344
• CPC Class Codes: A61B 2560/0242 adapted to measure environmental factors, e.g. temperature, pollution
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/14553 specially adapted for cerebral tissue
• CPC Class Codes: A61B 5/6814 Head

Abstract

A non-invasive near infrared spectrophotometric monitoring transducer assembly includes a housing member, which is adhered directly on a patient'"'"'s skin. The housing member contains a prism coupled to a flexible and lightweight single core optical light guide, which provides a means of transferring narrow spectral bandwidth light from multiple distant laser diodes of different wavelengths by use of a multi-fiber optic light combining assembly. Different wavelengths are needed to monitor the level of blood oxygenation in the patient. The assembly also contains a planar light guide mounted on the prism located in the housing member, which light guide contacts the patient'"'"'s skin when the housing member is adhered to the patient'"'"'s skin. The light guide controls the spacing between the prism and the patient'"'"'s skin, and therefore controls the intensity of the area on the patient'"'"'s skin which is illuminated by the laser light. The housing member contains a photodiode assembly, which detects the infrared light at a second location on the skin to determine light absorption. The photodiode assembly is preferably shielded from ambient electromagnetic interference (EMI) by an optically transparent EMI attenuating window. This rigid window placed over the photodiode also provides a planar interface between the assembly and the skin, improving optical coupling and stability as well as reducing the capacitive coupling between skin and the photodiode resulting in further EMI attenuation. The housing may be associated with a disposable sterile hydrogel coated adhesive envelope, or pad, which when applied to the patient'"'"'s skin will adhere the housing to the patient'"'"'s skin. The transducer assembly will thus be reusable, and skin-contacting part of the device, i.e., the envelope or pad can be discarded after a single use. The assembly also includes a laser safety interlock means, which is operable to turn off the laser light output in the event that the assembly accidentally becomes detached from the patient'"'"'s skin.

Claims

1. An infrared spectrometric monitoring transducer, comprising:

a light source operable to produce a light signal along a plurality of discrete wavelengths, mounted in a first pod;

at least one light detector operable to receive light energy corresponding to the light signal, mounted in a second pod that is independent of the first pod;

an electromagnetic interference shielding structure shielding the at least one light detector and mounted in the second pod such that light received by the at least one light detector must pass through the electromagnetic interference shielding structure; and

a light-shielding flexible member extending between the first and second pods.

2. The transducer of claim 1, wherein the transducer includes a first and a second light detector, both mounted in the second pod.

3. The transducer of claim 1, wherein the light-shielding flexible member is a cable.