The first line of prevention of secondary infection corresponds to compliance with the rules of hand hygiene, work surfaces and equipment carried out, the effect of which on the control of the incidence of secondary infection is regularly demonstrated. When declared, bacterial infection should be treated as quickly as possible with appropriate and effective antibiotics to preserve the healing prognosis. Compared to the infant and the larger child, clinical signs of calling are atypical and discrete. In the absence of staff trained to monitor newborns specifically, there is a real risk of discovering the existence of the infection only at an advanced stage corresponding, among other things, to circulatory collapse. This risk is not completely excluded, even with experienced practitioners, because the positive signs are rude and may go unnoticed (eg, signs of calling such as fever are rare in the newborn). Support for early diagnosis of neonatal infection by automatic monitoring systems has reduced mortality by 30% in the units where it has been applied. This is probably due to the fact that early warning made it possible to start the antibiotic treatment earlier and to complete the bacteriological diagnosis in order to better orient the therapeutic attitude. The best criteria for early diagnosis by automated systems were provided by the statistical analysis of cardiac variability, the results of the research and correspond to the standard deviation, the asymmetry and the entropy of the series d Cardiac intervals. Since microbial aggression has an impact on many vegetative variables outside of the electrocardiogram, our current research aims to determine whether the analysis of the perfusion index (PI) Which are of interest for detecting disturbances in the early stages of infection in newborns. IP corresponds to the ratio of the amplitude of the oscillating phase to the intensity of the constant part of the opto-plethysmography wave; It is obtained from signals recorded in a non-invasive manner by the same infrared sensor for pulse oximetry.