Laser-Doppler-flowmetry in preterm newborns during apneic events

Materials and methods. We have studied with Laser-Doppler-Flowmetry (LDF) Skin Blood Flow Perfusion (SBFP) during apneic events in 15 preterm newborns (mean GA 32.4 w; mean B.W. 1620). Eighty-four apneic episodes were analyzed and the results were gathered into two groups. Group 1 with SBFP belonging to preterms aged up to 5 days and Group 2 with SBFP records of some older newborns (from 5th to 10th day of life). At first a decrease of LDF was often observed during apneic events. Results. A statistically significant difference between the two groups was noted considering the SBFP percentage reduction, the hematocrit and the time of appearance of the skin blood flow decrease. We also studied the mean of all apneic SBFP reductions in each of those newborns (11/14) who had apneic events in both periods, observing a remarkable increase in mean SBFP reduction when the newborns were older than five days. Conclusions. These differences can be caused by rheologic factors such as high hematocrit, less pronounced red cell deformability and a sort of cold vasoparalysis more evident in the first days of life. We think laser-Doppler-flowmetry be suggested when the newborn is able to better contrast the negative effects of apnea, for example centralizing the circle in favour of vital organs.