Nonlinear analysis of fluctuations of microcirculation parameters in symmetrical organs of humans by laser doppler flowmetry
Purpose - the study the nonlinear dynamics of microcirculation parameters in human symmetrical organs. Material and Methods. Parameters of microcirculation were measured in healthy volunteers (aged between 50 and 70 years) by means of laser Doppler flowmetry (LDF). LDF signal transducers were fixed symmetrically on the lower parts of the right and left shoulders (3 cm above the elbow bend). The degree of chaoticity of microcirculation parameters as a nonlinear dynamic process was estimated using Hausdorff's index, relative entropy and characteristics of phase portraits. Along with components of the amplitude-and-frequency range for blood flow fluctuations (myogenic, neurogenic, respiratory, and cardiac) was estimated and correlations between all characteristics of microcirculation in both sides of the body were done. Results. Asymmetry of correlation relationships of nonlinear dynamics parameters and components of the amplitude-and-frequency range for blood flow fluctuations of right and left sides of the body was revealed. Hausdorff index in the left side correlated not only with the average value of perfusion and with the coefficient of variation in the same side (r<sub>1</sub>= -0.68; r<sub>2</sub>=-0.51), but also with correlation dimension of chaos in the opposite side (r=0.49). Similarly, entropy in the left side correlated not only with the average value of perfusion and coefficient of variation in the left (r<sub>1</sub>=0.43; r<sub>2</sub>=0.60), but also with the entropy and correlation dimension of chaos in the right side (r<sub>1</sub>=0.48; r<sub>2</sub>=-0.41). The neurogenic component in the left side positively correlated with the myogenic component in the same side (r=0.71). A positive correlation was observed between the neurogenic component in right side and myogenic component in the opposite side (r=0.57). Asymmetry of correlation relationships was also revealed for the respiratory and cardiac components. Conclusions. Our results illustrate the specific regulation of blood flow in micro vessels of paired organs, which is associated with functional asymmetry. The physiological mechanisms for this asymmetry require further experimental and clinical studies.