Autonomous nervous system assessment in mechanical ventilated preterm newborns by using special analysis of heart rate variability

Heart rate variability (HRV), meaning the variation between R-R of two cons ecutive bents on the ECG truer, is modulated by different factors, both dev elopmental (gestational age), and physiological (respiration, sleeping, etc .), pathological (RDS, neuropathies), and therapeutic (drugs which interfer e with autonomous nervous system) or intensive care approaches (bronchoaspi ration, intubation, mechanical ventilation). The present study aims to eval uate the autonomous nervous system (ANS) development and efficiency in very low birth weight (VLBW) newborn babies through the utilization of power sp ectral analysis of HRV. Finally an innotave methodology, of HRV analysis by real time spectral is explaned. Two groups of newborns were examinated. Gr oup I composed of 9 healthy babies and group 2 composed of 8 VLBW mechanica l ventilated newborns. A 5 minute registration of the ECC monitor trace in second da? life was performed for each baby. Analogical data have been tran sformed into digital form and 200 beat periods, during which the signal was as stationary as possible, were computed through autoregressive approach. Finally the respective power spectra were displayed. The following frequenc y bands have been taken into account: low frequency (LF), indicating ortosy mpatethic influence, between 0.05 and 0.2 Hz. High frequency (HF), which ar e indicative of parasympathetic activity over 0.2 Hz. Power spectrum densit y of HRV has been expressed by the area under the curve of the peaks pointe d out at the difference frequency bands.;The mechanisms of the increase of HF in the mechanical,ventilated newborns is a result of a parasympathetic a nd sympathetic (short circuits of thorax baroreflex). ANS seems to Dc highl y responsive already at 26 weeks GA. Probably it is still insufficiently or ganized and auto-regulated fu, the unripe neuronal network and immaturity o f the feed-back systems.