 Newborn babies admitted to the NICU and well baby will be connected to a specially designed photoplethismograph PPG. Right hand pre ductal, and and one of the legs postductal values will be compared, based on the formula Delta amplitude of PPG baseline absorption perfusion index PI. Normal values will be defined in healthy term and preterm babies, and clinical conditions in which the PI is expected to change Patent Ductus Artheriosus, Persistent pulmonary hypertension of the newbornwill be compared with these normal values. 