Cerebral near-infrared spectroscopy correlates to vital parameters during cardiopulmonary bypass surgery in children.

Near-infrared spectroscopy (NIRS) can monitor changes in cerebral regional oxygen saturation (rSO2) and tissue hemoglobin content (HbT). The relation between cerebral NIRS readings and vital parameters has not been analyzed before at a fine temporal scale. This study analyzed this relation during cardiopulmonary bypass (CPB) surgery in 10 children (0-9 years, 1,770 min of data records) by using a novel random-coefficient model. The analysis indicated that a small number of patients is sufficient for obtaining significant results with this model. Changes of vital parameters explained 84.7 % of rSO2 changes and 90.7 % of HbT changes. Cerebral rSO2 correlated positively with perfusion pressure and inversely with body temperature (P < 0.05). Cerebral HbT correlated positively with perfusion pressure, central venous pressure, and temperature and inversely with arterial oxygen saturation (P < 0.05). During hypothermic circulatory arrest, the half-life of the exponential rSO2 decay correlated to the rSO2 reserve (P = 0.016). In conclusion, NIRS readings of cerebral hemoglobin content and tissue oxygen saturation correlate well to vital parameters during CPB surgery in children. NIRS may therefore become a monitoring device for the neuroprotective optimization of those vital parameters.