MIBE Online Seminar: Spectroscopic measurement of blood parameters ex vivo

Titel: Spectroscopic measurement of blood parameters ex vivo

Sprecher: Franziska Palme, M.Sc. candidate (Gleich Group)

Datum und Uhrzeit: Dienstag, 16. November, 13:00 Uhr

Abstract: In intensive-care units there is a need for point-of-care diagnostic of various blood parameters to get
information about the patient’s condition rapidly. Currently, healthcare professionals are taking an
arterial or venous blood sample and analyze it via a blood gas analyzer (BGA) several times a day. After
analyzation the blood sample is discarded. By integrating a sensor system to the blood aspiration
system blood loss and possibly resulting anemia could be reduced. This integration may also lower the
workload for healthcare professionals as no external analyzation steps are demanded.
At present, B. Braun is developing an optical sensor system, which can determine the most important
blood parameters ex vivo without the use of a BGA. First, the patient’s blood is taken by an aspiration
system. During analyzation the blood remains in the system and is reinfused to the patient afterwards.
There are two principles used for the optical determination of blood parameters. First, fluorescence
spectroscopy where glucose, lactate, oxygen, carbon dioxide, pH, sodium ions, and potassium ions are
assessed with the help of appropriate fluorophores. The remaining essential blood parameters
- hemoglobin, hematocrit, and oxygen saturation - can be evaluated by spectroscopy as these
parameters have a characteristic absorption (see figure 2). Spectroscopy does not require any
fluorophores but measures the reflection (or transmission) by a blood sample.
The goal of this master thesis is to develop a functional sample for the spectroscopic measurement of
hemoglobin, hematocrit, and oxygen saturation. Spectroscopy requires a light source (or optical
emitter) and at least one detector to evaluate the amount of reflected or transmitted light. The
mechanical construction in figure 1 comprises several emitters and detectors, which are arranged
alongside a blood tube. When light from an emitter hits a blood cells it is scattered. Thus, it is either
absorbed or reflected. The remaining spectral intensity is transmitted to the opposite detectors. The
amount of reflected and transmitted light is assessed to determine hemoglobin and hematocrit level
as well as the oxygen saturation of the blood sample.