Effect of posture on brain hemodynamics in preterm newborns not mechanically ventilated

Background: Changes in head posture influence brain hemodynamics. Optimal positioning has been recommended as 1 of 10 potentially better practices to reduce the incidence of brain injury in preterm newborns. Objectives: The aim of this study was to evaluate by near-infrared spectroscopy (NIRS) the effect of different head and body positions and the influence of gestational age (GA) and nasal continuous positive airway pressure on brain hemodynamics in very preterm newborns. Methods: 24 stable preterm newborns were studied by NIRS in 6 different postures including head rotation and head inclination in both supine and prone positions. Changes in normalized tissue hemoglobin index (nTHI) and tissue oxygenation index (TOI) were measured after posture variations. Results: No statistically significant changes in nTHI and in TOI were found in the 6 postures. nTHI variations, expression of cerebral blood volume variations, were influenced by GA. A reduction in nTHI, with a stable TOI, in the less mature infants (with GA ≤26 weeks), occurred on head rotation; nTHI increased again when the head was derotated. Conclusions: Hemodynamic changes after posture variations depend on GA. Head rotation in newborns with GA ≤26 weeks produced a reduction in nTHI with stable TOI. Possible physiopathological mechanisms are discussed.