[Cerebral hemodynamics and major surgery].

AIM: Near infrared spectroscopy (NIRS) is a non invasive optical technique to assess the monitoring of oxygenation and cerebral hemodynamics. Aim of our study was to value cerebral hemodynamics during major surgery to reduce the period of possible modifications of cerebral oxygenation.

METHODS: Twenty-five newborns which underwent surgical intervention (8 diaphragmatic hernia, 8 esophageal atresia, 1 neck lymphangioma, 8 intestinal malformation) were studied during surgery by means of NIRS (NIRO 300), using an electrode applied to the scalp in the frontoparietal region. We monitored the Tissue Oxygenation Index (TOI) as well as the changes in concentration of total haemoglobin (tHb), oxygenated haemoglobin (O2Hb) and deoxygenated haemoglobin (HHb). The changes have been expressed as difference from the basal value recorded at the beginning of surgery.

RESULTS: During the surgical intervention O2Hb, tHb and TOI decreased (DeltaO2Hb=-11.4+/-6.5 microM; P<0.001; DeltatHb=- 7.54+/-4.3 microM, P<0.05; microTOI=-12.5+/-5.5%, P<0.001), and HHb increased (DeltaHHb=+4.80+/-2.30 microM, P<0.001); the greatest changes occurred when the viscera were positioned into the abdomen (in diaphragmatic hernia and intestinal malformation).

CONCLUSION: The present study suggests that NIRS, during major surgery, is able to monitor oxygenation and cerebral hemodynamics thus allowing a real time evaluation of some intraoperative procedure aftereffects that, if timely modified, could reduce cerebral hypoxia risks.