Effect of head positioning on cerebral blood velocity in the basilar artery in neonates and young infants: A single-center, retrospective analysis

Head rotation and subsequent hypoperfusion of the brain stem might be possible causal factors of sudden infant death. This study aimed to determine the quantitative changes of cerebral blood flow as assessed on ultrasound (US) Doppler with respect to dependence on the position and age of the subject.This single-center retrospective study was performed to assess US Doppler measurements on vertebral and basilar arteries of neonates and infants. After measuring peak systolic flow (Vs) and time-averaged velocity (TAM) in the middle supine position, each subject was positioned with the head rotated to the right and left both in a supine and a prone position. Both vertebral arteries were measured, and results were correlated to individual age at the time of investigation.A total of n=1889 subjects were analyzed. Vs was 63.0±15.3cm/s in the supine middle position and reduced after head rotation to 59.9±21.6 m/s (P <0.0001, head rotated right) and 59.4±15.6cm/s (P <0.0001, left). In the prone position Vs was 58.4±14.8cm/s (P <0.0001, head rotated right) and 58.1±15.0cm/s (P <0.0001, left). Comparable measurements were made for TAV. There was a correlation of TAV and Vs with individual postnatal age.Head rotation and different positioning of the neonate/young infant leads to lower Vs and TAV values in the basilar artery. It remains unclear if these changes may help to identify patients at risk of SIDS. Furthermore, Vs and TAV are age-dependent, which should be considered in the workup of transfontanellar US Doppler investigations.