Optical detection and quantification of microair in blood

• US 6,529,751 B1
• Filed: 02/08/1999
• Issued: 03/04/2003
• Est. Priority Date: 04/29/1997
• Status: Expired due to Fees

• Current Assignee: Medtronic Avecor Cardiovascular Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Meyer, Craig R., Wong, Yu-Tung, Zollinger, David L., Van Driel, Michael R., Flores, Juan Carlos, Ingle, Aaron S., Jeffery, Jorge
• Primary Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US09/246,342
• Time in Patent Office: 1,485 Days
• Field of Search: 600/310, 600/322, 604/65, 604/67, 604/122, 604/123, 250/338.1, 250/343, 250/573, 250/574, 250/575, 250/576, 340/619, 340/632, 340/627, 738/614.1
• US Class Current: 600/322
• CPC Class Codes: A61M 1/3626 Gas bubble detectors

Abstract

Both the number and the size of microair bubbles in a bloodstream are accurately determined optically, independently of oxygen saturation, by monitoring the intensity of light transmission in the 800-850 nm range through the bloodstream and indicating the count and amplitude range of peaks in the monitored intensity.

Claims

1. An optical detector for detecting and measuring microair bubbles in a bloodstream, comprising:

a) a rigid transparent conduit for said bloodstream;

b) at least one light source positioned adjacent said conduit, said light source transmitting light having a wavelength substantially in the range of 800-850 nm through said conduit;

c) at least one light receiver positioned adjacent said conduit opposite said light source, said light receiver producing a signal representative of the light intensity impinging upon said receiver;

d) an apparatus operatively connected to said receiver to provide an indication, as a function of said signal, of the number and size of microair bubbles passing said detector.

2. The detector of claim 1, in which said apparatus includes a comparison device arranged to detect the occurrence and amplitude range of peaks in said signal.

3. The detector of claim 1, in which said at least one light source and said at least one receiver are disposed in at least one opposing pair, each pair having a light source and a receiver.

4. The detector of claim 3, in which sufficient pairs are disposed around said conduit to illuminate substantially all of the cross-sectional area of said conduit.

5. The detector of claim 1, in which a plurality of detectors spaced from one another in a direction axial of said conduit are disposed about said conduit.