Abstract: An optical blood monitoring system includes a sensor clip assembly and a blood chamber. The blood chamber has an internal flow cavity for extracorporeal blood flow and viewing lenses to enable the sensor clip assembly to monitor the blood when it is mounted on the blood chamber. The sensor clip assembly includes an annular shroud surrounding the LED emitters and another annular shroud surrounding the photodetectors, both for the purpose of blocking ambient light and limiting light piping. The blood chamber includes separate, distinct shroud mating surfaces to engage the shrouds on the sensor clip assembly.

Abstract: A sensor clip assembly for an optical blood monitoring system includes a circuit board with a microprocessor that is programmed with a ratiometric model to calculate hematocrit and/or oxygen saturation levels of a patient.

Abstract: An extracorporeal blood chamber for an optical blood monitoring system has a mixing area and viewing area that are offset from the axis of the blood flow path into and out of the blood chamber. The off-axis design provides more leverage for threading the blood chamber onto a dialysis filter. It also eliminates the need for turbulence posts.

Abstract: A low flow blood chamber for optically monitoring blood flowing through extracorporeal tubing has a flat elongated blood flow cavity but preserves the circular viewing area of conventional blood chambers. The blood chamber provides consistent, mixed flow through the blood cavity even at low blood flow rates, e.g. 10 to 500 ml/min., while maintaining certain dimensional characteristics of conventional blood chambers.

Abstract: An extracorporeal blood chamber for an optical blood monitoring system includes an opaque chamber body in order to prevent inaccuracies when measuring oxygen saturation levels due to light ducting, which can occur at low oxygen saturation levels and low hematocrit levels. In one embodiment, the blood chamber need not include a moat as is present in conventional blood chambers.

Abstract: An optical blood monitoring system with a ratiometric model determines hematocrit values for a hemodialysis patient, from which hemoglobin values for the patient are estimated. The ratiometric model is calibrated, normally against a cell counter, using blood from a blood bank. The blood from a blood bank is preserved in a long term preservative which is typically different than that found in clinical settings. The hematocrit value determined by the ratiometric model is scaled by scaling factor so that the estimated hemoglobin level output from the monitor consistently matches that measured in a clinical setting. The hematocrit scaling factor is substantially about 1.033 when the patient's blood sample is stored in a short term preservative ethylene diamine tetra acetic, and is substantially about 1.06 when the hematocrit is measured in the blood sample without preservative being added to the blood sample. The hemoglobin value can also be adjusted for altitude.

Abstract: A hemodialysis patient data acquisition and management system resides on a host computer which receives information from one or more non-invasive, optical blood monitors associated with a hemodialysis system. When a patient is undergoing hemodialysis treatment, a sensor assembly monitors the patient's blood flowing through the hemodialysis system and a controller for the blood monitor generates data which includes at least an identification code for the patient undergoing the treatment on the respective system, and non-invasively determined blood data taken at the onset of the scheduled treatment, such as initial Hgb, HCT, and SAT values. A host computer communicates with the one or more optical blood monitors, preferably via a wireless network, and the patient's session commencement data is downloaded to the host computer.