Background and aims Sepsis is major cause of neonatal morbidity and mortality. The level of organ dysfunction is related to the severity of sepsis, as milder episodes seem to lead to less injury. Our aim was to evaluate differences in brain oxygenation, measured by Near Infrared Spectroscopy (NIRS) and estimated via TOI (Total Oxygen Index) and FTOE (Fraction Tissue Oxygen Extraction), according to the sepsis severity.

Methods We designed a prospective study in the 2nd NICU of AUTH, Greece, between 6/2012–12/2012. Neonates with confirmed sepsis underwent 3 NIRS measurements on day 1, 3 and 7 of the episode. Sepsis was classified according to IPSCC criteria into: Sepsis, Severe Sepsis and Septic Shock.

Results Fifty neonates were enrolled with equal birthweight (sepsis: 1610 gr, severe sepsis: 1670 gr, septic shock: 1550 gr) and gestational age (31, 31, 30 weeks respectively).

A TOI decrease/FTOE increase in the 7th day was recorded in all groups (Sepsis: TOI: 68, 70, 62, FTOE: 29%, 27%, 35%, Severe sepsis: TOI: 66, 70, 62, FTOE: 29%, 27%, 33%, Septic Shock: TOI: 64, 66, 61, FTOE: 33%, 29%, 35%). Neonates with severe sepsis and septic shock required more intensive management and had worst outcome. The brain oxygenation, however, was equally decreased in all 3 groups (p > 0.05), irrespectively to the severity of the septic episode.

Conclusion The outcome of the neonates is proportionally depended to the severity of sepsis, however, even the milder forms seem to cause significant decrease on the brain oxygenation and potential equal brain injury.