Impaired Autoregulation in Preterm Infants Identified by Using Spatially Resolved Spectroscopy

Abstract

High coherence between mean arterial blood pressure and tissue-oxygenation index indicates impaired cerebral autoregulation in clinically sick preterm infants and is strongly associated with subsequent mortality. Cross-spectral analysis of mean arterial blood pressure and tissue-oxygenation index has the potential to provide continuous bedside assessment of cerebral autoregulation and to guide therapeutic interventions.

Respiratory support for premature neonates in the delivery room: effects on cardiovascular function and the development of brain injury

“…The majority of abnormal CBF is due to impaired cardiovascular control (38). Abnormal fluctuations in CBF are not usually a problem in term infants because they have the ability to maintain near-constant blood flow in the face of changing perfusion pressures by altering cerebral vascular resistance (autoregulation) (39). However, preterm infants commonly have episodes of impaired autoregulation, primarily due to immaturity of or injury to the cerebral vascular bed (40).…”

Measuring cerebrovascular autoregulation in preterm infants using near-infrared spectroscopy: an overview of the literature

“…Tsuji et al found a higher coherence score in the very-lowfrequency range for preterm infants with severe cerebral ultrasound abnormalities (grade 3-4 GMH-IVH or PVL) compared to infants with normal or minimal abnormal ultrasound findings [6]. Also, Wong et al showed highest coherence and gain in the very-low-frequency range (0.003-0.02 Hz) [34].…”

“…Clinical factors related to impaired cerebrovascular autoregulation are lower gestational age (GA) [29,34,35], lower birth weight (BW), lower glucose levels [29,34,36], higher clinical risk index for babies (CRIB) score [34], increased infant mortality [34,37], and higher PaCO 2 levels [15,38,39]. Perinatal risk factors such as pregnancy induced hypertension; antepartum hemorrhage and placental infarction are also associated with impaired cerebrovascular autoregulation [29].…”

“…Others focus on the techniques and hardly give any information on the infants included, which may hamper interpretation of data presented. Out of the 25 articles studied, 14 mention PaCO 2 as a possible confounder, of which 3 actually measured PaCO 2 and assessed the relationship between PaCO 2 and outcome [34,41,42] and 2 assessed the influence of PaCO 2 on cerebrovascular autoregulatory measures [29,56]. None found any relation between PaCO 2 , outcome, and autoregulation status.…”

“…Wong et al assessed dynamic cerebrovascular autoregulation in the frequency domain, in 24 very preterm infants (GA <32 weeks). They employed a moving window of frequency-specific MABP and TOI measurements using TFA [34] (Figure 3). They computed 'power spectral densities' from the frequency-domain data, which were used to generate the TFA variables coherence and gain from the two signals.…”