Joseph E Culver

US Patent:

6487428, Nov 26, 2002

Filed:

Aug 31, 2000

Appl. No.:

09/652757

Inventors:

Joseph P. Culver - Philadelphia PA
Arjun G. Yodh - Merion PA

Assignee:

Trustees of The University of Pennsylvania - Philadelphia PA

International Classification:

A61B 500

US Classification:

600310, 600309, 600475

Abstract:

Extravasation of a fluid applied to a patient is determined by monitoring light transmitted through the tissue of the patient in proximity to a site at which the fluid is being injected. Light is radiated from a plurality of light sources in an encoded manner into the body part at the site at which the fluid is injected and the light that is reflected, scattered, diffused or otherwise emitted from the body part is detected individually by a plurality of light detectors. Signals representative of the detected light are developed and, prior to injection of the fluid, references are developed against which measurements made during injection of the fluid are compared. New light signals having an improved signal-to-noise ratio are developed from the comparisons of the detected light signals with the associated reference signals. Prior to injection of the fluid into the body part, a model, dependent on the arrangement of the light sources and the light detectors on the support pad is developed for calculating extravasation volume from the new light signals having an is improved signal-to-noise ratio. The new light signals having an improved signal-to-noise ratio are combined according to the model to determine the volume of extravasation and the volume of extravasation is compared with a prescribed level of extravasation.