Technology and Health Care - Volume 7, issue 2-3

Authors: Popivanov, D. | Mineva, A. | Dushanova, J.

Article Type: Research Article

Abstract: Methods for tracking the dynamics of the blood flow microcirculation obtained by laser-Doppler flowmetry (LDF) technique are described. It was shown that LDF signals have complex dynamics. It was mainly characterized by fractal structures and chaos, though multiperiodic, trend-like and stochastic components were also established. Procedures for (i) describing the dynamic structure and (ii) tracking the dynamic changes in time of LDF data are proposed. Examples illustrating the efficiency of these procedures are given using both simulated and LDF data collected in experiments with reactive hyperemia. Irrespective of the universality of the methods, the procedures should be specified according to …the problem-oriented clinical and experimental studies. Show more

Keywords: Blood flow, laser-Doppler flux, nonlinear dynamics, chaos, fractal, hyperemia

DOI: 10.3233/THC-1999-72-311

Citation: Technology and Health Care, vol. 7, no. 2-3, pp. 205-218, 1999

Authors: Söderström, Torbjörn | Svensson, Henry | Koop, Thoralf | Möller, Karl O.

Article Type: Research Article

Abstract: As conventional graphical laser-Doppler flowmetric (LDF) registrations from free flaps are difficult to interpret we explored the use of refined computerized signal processing to enhance the reliability of the blood flow supervision postoperatively. From eleven free flaps LDF data were collected using a software programme and a personal computer for analysis. Findings were compared with the clinical outcome. Nine flaps healed whereas one had wound problems and one suffered a partial necrosis. From the nine uneventful flaps, a peak within the range of frequencies from 0.04 to 0.23 Hz was seen. In the remaining two, such a low frequency peak …could hardly be observed. Frequency analysis using computerized processing of LDF signals thus has the capacity to demonstrate the status of the flap perfusion. The slow wave vasomotion component seems to be of particular importance. Other frequency components warrant further investigation. A custom made monitoring device would be of great clinical value. Show more

Keywords: Free flap, microsurgery, monitoring, blood flow, vasomotion, frequency analysis

DOI: 10.3233/THC-1999-72-312

Citation: Technology and Health Care, vol. 7, no. 2-3, pp. 219-223, 1999

Authors: Stefanovska, Aneta | Leger, Philippe | Bračič, Maja | Bračič, Toni | Bendayan, Pierre | Boccalon, Henri

Article Type: Research Article

Abstract: The paper presents analyses of the dynamics contained in the blood flow signals measured on healthy subjects and on subjects with primary Raynaud’s phenomenon. Different signal processing methods are presented and discussed. The dynamics was evaluated in the time and frequency domains and in phase space. Additionally, changes in the basal value during temperature provocation were studied using multiresolution analysis. The analyses demonstrate differences between the blood flow dynamics in healthy subjects and subjects with Raynaud’s phenomenon. Moreover, the observed decrease in the amplitude of oscillation in regions ≈ 0.04 Hz and ≈ 0.1 …Hz suggests an impairment in the neurogenic and the myogenic regulation of the blood flow. The administration of nifedipine in subjects with Raynaud’s phenomenon results in an increase in the basal value and in the amplitude of the blood flow component oscillating with the heart rate. However, it does not restore the dynamics to that found in healthy subjects. Show more

Keywords: Mathematics – algorithms (H1.548.35), nonlinear dynamics (H1.548.675), blood circulation (G9.330.163), hemodynamics (G9.330.612.+), Raynaud’s disease (C14.907.744.+), nifedipine (D3.383.725.203.540)

DOI: 10.3233/THC-1999-72-313

Citation: Technology and Health Care, vol. 7, no. 2-3, pp. 225-241, 1999