Evaluation

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Evaluation Studies of the O2C
Evaluation Studies of OptoFlow

Evaluation Studies of the O2C

Correlation with Microspheres and cerebral venous oxygen saturation

The parameter measured by O2C were compared to "Goldstandard" in brain of piglets:

Blood flow velocity measured by O2C was compared with perfusion measured by Microspheres.

Local oxygen saturation measured by O2C was compared with cerebral venous oxygen saturation.

By stepwise decrease of intracerebral perfusion pressure, perfusion of brain was decreased. The measurements with O2C show decreasing blood flow velocity, as well as the perfusion measured with microspheres. Also local oxygen saturation measured with O2C and cerebral venous oxygen saturation decreased.
In the following reperfusion period all values increased and indicated reactive hyperemia. After 30 minutes all values decrease again to a level below baseline (Fig. 1)
Blood flow velocity, as well as local oxygen saturation measured with O2C correlated well with perfusion measurement by microspheres and cerebral venous oxygen saturation, respectively (Fig. 2).


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Figure 1: Local oxygen saturation (blue) and blood flow (green) determined by O2C and cerebral venous oxygen saturation (orange) during stepwise decrease of perfusion pressure in pig brain and following reperfusion.


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Figure 2: Correlation of blood flow measurement with O2C and microspheres

Reproducibility Study

In 5 volunteers the O2C parameter were determined on 3 consecutive days. No significant changes have been shown during this observation period.

Literature:

Empho

Papers:

Evaluation Studies of OptoFlow

The blood flow was measured on two consecutive days on one volunteer and on different volunteers. The inter-subject variability of blood flow values in different depths were between 32 and 37 %. An average 5 % of intra-subject variability was observed.

Literature: