CEREBRAL BLOOD-FLOW AND PLASMA HYPOXANTHINE IN RELATION TO SURFACTANTTREATMENT

We have previously reported reduction in EEG activity in preterm babie s after tracheal instillation of Curosurf To elucidate the cause of EE G depression, we have examined cerebral blood flow (CFB), amplitude-in tegrated EEG (aEEG), mean arterial blood pressure (MABP) and plasma hy poxanthine (Hx) concentration in a group of preterm babies before and immediately after administration of surfactant. No change occurred in CBF immediately after surfactant treatment despite a significant decre ase in MABP. At 60 min after surfactant administration, a significant reduction in CBF occurred (p < 0.05). However, when CBF values were co rrected for changes in PaCO2, no reduction in CBF was observed. Mean p lasma Hx concentration was 11.6 (SD 7.3) mu mol/l before surfactant th erapy, which decreased significantly to 8.1 (5.8) mu mol/l (p < 0.05) 15-30 min after treatment. No correlations were found between plasma H x concentration and FiO(2), a/A pO(2), PaCO2, SaO(2), arterial blood p ressure, CBF or the degree of EEG depression. This study indicates tha t EEG depression observed after surfactant instillation is not caused by cerebral ischemia.