Disposable extracorporeal conduit for blood constituent monitoring

A disposable blood cuvette, defining a fluid passageway for containing and conducting therethrough blood flowing under pressure in a pulsatile fashion, comprising:

• a. an inlet;
• b. an outlet;
• c. a conduit, having an essentially cylindrical shape and being in fluid communication both between and with said inlet and outlet and being comprised of materials which permit transmission of at least two predetermined wavelengths of electromagnetic radiation therethrough, comprising:
• i. opposed first and second walls, having a predetermined separation therebetween, and constraining the pulsatile flowing blood therebetween, and wherein for each pulse of said pulsatile flowing blood said first wall makes a resilient fluctuation so as to vary said predetermined separation and said second wall is essentially immobile;
• and
• ii. a vertical wall, situated both outside and in between said first and second walls, said blood flowing in a pulsatile fashion in contact with both said vertical wall and said first and second walls.

A disposable fluid cuvette, for defining a fluid passageway for containing and conducting therethrough a fluid flowing in a pulsatile fashion, comprising:

• a. a first fluid conduit, having an inlet and an outlet and a lumen therebetween;
• b. a second fluid conduit, comprised at least in part of materials essentially permitting transmission of at least two predetermined wavelengths of electromagnetic radiation therethrough, and comprising:
• i. an inlet in fluid communication with the outlet of the first fluid conduit;
• ii. means, in contact with said pulsatile flowing fluid, for making a resilient fluctuation with each pulse of said pulsatile flowing fluid in a direction essentially normal to the general direction of movement of the pulsatile flowing fluid;
• and
• iii. an outlet;
• c. a third fluid conduit, having an inlet and an outlet and a lumen therebetween, said inlet of said third fluid conduit being in fluid communication with the outlet of the second fluid conduit.