Sensor for transcutaneous measurement of vascular access blood flow
AssigneeHema Metrics, Inc.
InventorsRobert R. Steuer, David A. Bell, David R. Miller
Life of this patent
Estimating the term…
Abstract
An optical sensor includes photoemitter and photodetector elements at multiple spacings (d1, d2) for the purpose of measuring the bulk absorptivity (α) of an area immediately surrounding and including a hemodialysis access site, and the absorptivity (αo) of the tissue itself. At least one photoemitter element and at least one photodetector element are provided, the total number of photoemitter and photodetector elements being at least three. The photoemitter and photodetector elements are collinear and alternatingly arranged, thereby allowing the direct transcutaneous determination of vascular access blood flow.
Claims13
A sensor for the transaction measurement of vascualr access blood for flow comprising:
- a substrate having an axis and an access placement line perpendicular to the axis;
- an inboard emitter and an inboard detector positioned on the substrate on either side of and spaced the same distance from the access placement line;
- and
- at least one of an outboard emitter and an outboard detector spaced a distance from the inboard detector and the inboard emitter, respectively.
A sensor of the transcutaneous measurement of vascular access blood flow, the sensor having an access placement line and comprising:
- a first emitter and a first detector positioned on either side of and space the same distance δ from the access placement line;
- and
- a second emitter and a second detector positioned on either side of and spaced the same distance δ from the access placement line, the first and second emitters being arranged along a first diagonal line having a point of intersection and forming an angle with the access placement line and the first and second detectors being arranged along a second line at an angle to the first line at the point of intersection with the access placement line.
A sensor for the transcutaneous measurement of vascular access blood flow, the sensor having an access placement line and comprising:
- a first emitter and a first detector positioned on either side of and spaced the same distance δ from the access placement line;
- and
- a plurality of additional detectors arranged in alignment along a line defined by the first emitter and the first detector.
Apparatus for non-invasively measurement one or more blood parameters associated with a vascular access site, comprising:
- means for optically measuring a blood parameter in a volume of tissue parallel to and excluding the access site;
- and
- means for optically measuring the blood parameter in a volume of tissue perpendicular to and including at least a portion of the access site.
Dependencies are inferred from the claim text.