CEREBRAL HYPOXIA AFTER HYPERVENTILATION CAUSES RE-BUILD-UP PHENOMENONAND TIA IN CHILDHOOD MOYAMOYA DISEASE - A NEAR-INFRARED SPECTROSCOPY STUDY

Near-infrared spectroscopy was used to monitor the sequential changes in the cerebral oxygenation state during and after hyperventilation in two children with moyamoya disease. Hyperventilation induced the buil d-up phenomenon and a decrease in the concentration of oxy-hemoglobin ([oxy-Hb]) and total hemoglobin ([t-Hb]). The termination of hypervent ilation was followed by partial recovery of [oxy-Hb] and [t-Hb], Subse quently, however, [oxy-Hb] and [t-Hb] decreased again and cytochrome o xidase was reduced. These impairments of the cerebral hemodynamics and oxygen metabolism were closely associated with the re-build-up phenom enon on EEG and with transient ischemic attacks (TIA). The present stu dy implies that cerebral hypoxia after hyperventilation is closely rel ated to the re-build-up phenomenon and ischemic attacks in children wi th moyamoya disease.