[Evaluation of cerebral oxygenation in newborns with prematurity apnea: new frequency domain NIR oximeter].

Near infrared spectroscopy (NIRS) is a non invasive, portable, safe technique for monitoring cerebral oxygenation and haemodynamics. A new frequency-domain tissue oximeter based on a multi-distance measurement protocol is presented. The effects of apneic episodes on cerebral and peripheral arterial oxygen saturation (SatO2) in preterm newborns, as monitored by NIRS and by pulse oximetry, are reported. The study population consist of 5 preterms (26 to 30 weeks of gestational age), in the second week of postnatal age, affected by apnea of prematurity. NIRS and pulse oximetric measurements were made contemporarily for a 40-minutes period for each infant. All monitorized apneic events were associated with bradicardia, and resolved spontaneously or after tactile stimulation. As results: a) there was always cerebral deoxygenation in association with apneic events, b) the mean SatO2 as measured by NIRS was slightly lower than the pulse oximeter readings, c) cerebral SatO2 decreased faster and the absolute value of the cerebral SaO2 decrease was greater than that measured peripherally (mean value of 27 versus 13%), d) increases of cerebral deoxyhemoglobin and total hemoglobin and a decrease of oxyhemoglobin were also observed. These preliminary results show that peripheral oxygen saturation measurements as measured by pulse oximetry could not always reflect brain oxygenation.