Department of Vascular Surgery, Centre for Postgraduate Medical Studies, Warsaw, Poland
A new extremely promising method - laser Doppler capillarometry (anemometry) is currently being introduced. It allows not only direct blood flow velocity measurements from single capillaries, but also, is not limited to the region of nailfold. This is because of a completely new idea of capillary blood flow measurement. The aim of the study was to verify the real blood flow velocity values and the sensitivity of the equipment.
Material and methods: Real capillary blood flow velocity values and sensitivity to flow changes were checked in an in vitro model. The flow velocity and its changes were measured using a CAM1, Exeter, UK anemometer. The results were compared against the results of flow achieved by 20MHz pulsed Doppler (EME, Pioneer) and against the values achieved from the calibrated infusion unit. The data were compared using a Students t'test.
Results: Flow velocities and the changes in their values compared favourably (>95%) with the results from calculated flow of infusion and (>97%) with the results achieved from the same model by 20MHz pulsed Doppler. In the model set-up, flow spectrum acquired by laser Doppler anemometer had exactly the same properties of laminar flow, as one obtained from the 20 MHz Doppler. The differences between flow values following change of flow were highly significant (p>0.0001).
Conclusions: Laser Doppler capillarometer (anemometer) enables to achieve real blood flow velocity values, is well calibrated and highly sensitive to flow changes. The flow pattern (spectrum) achieved by laser Doppler method has the same properties as spectrum of flow in the classic Doppler method.