Optimal oxygen saturation in extremely premature neonates.

So far, great efforts have been made to understand the demands of extremely premature neonates (EPNs´; born before the 28(th) week of gestation) on postnatal care, including optimal oxygen saturation, that will allow them to survive without disability. A major yet unresolved problem is to find an "optimal range" of their oxygen saturation and to maintain it without drops or increases, i.e., without hypoxia or hyperoxia. The individual sections of this paper deal with the changes of SpO(2) (an estimate of SaO(2) measured by pulse oximetry) that occur before, during, and after premature labor, postnatal factors affecting SpO(2), and especially how to find an acceptable compromise in choosing the most effective and minimally harmful range of SpO(2) for EPNs' with the careful FiO(2) adjustment and continually monitored SpO(2). At present, the two SpO(2) ranges, narrow (90-94%) vs. wider (88-94%), are most discussed. However, the question of how much oxygen is too much or little remains unanswered. There is even a view that there is no uniform optimal SpO(2) range for EPNs, and that each newborn has its own, individually specific range that changes due to its intrinsic and/or extrinsic factors.