Elevated Cerebral Pressure Passivity Is Associated With Prematurity-Related Intracranial Hemorrhage

Abstract

OBJECTIVES Cerebral pressure passivity is common in sick premature infants and may predispose to germinal matrix/intraventricular hemorrhage (GM/IVH), a lesion with potentially serious consequences. We studied the association between the magnitude of cerebral pressure passivity and GM/IVH. PATIENTS AND METHODS We enrolled infants <32 weeks’ gestational age with indwelling mean arterial pressure (MAP) monitoring and excluded infants with known congenital syndromes or antenatal brain injury. We recorded continuous MAP and cerebral near-infrared spectroscopy hemoglobin difference (HbD) signals at 2 Hz for up to 12 hours/day and up to 5 days. Coherence and transfer function analysis between MAP and HbD signals was performed in 3 frequency bands (0.05–0.25, 0.25–0.5, and 0.5–1.0 Hz). Using MAP-HbD gain and clinical variables (including chorioamnionitis, Apgar scores, gestational age, birth weight, neonatal sepsis, and Score for Neonatal Acute Physiology II), we built a logistic regression model that best predicts cranial ultrasound abnormalities. RESULTS In 88 infants (median gestational age: 26 weeks [range 23–30 weeks]), early cranial ultrasound showed GM/IVH in 31 (37%) and parenchymal echodensities in 10 (12%) infants; late cranial ultrasound showed parenchymal abnormalities in 19 (30%) infants. Low-frequency MAP-HbD gain (highest quartile mean) was significantly associated with early GM/IVH but not other ultrasound findings. The most parsimonious model associated with early GM/IVH included only gestational age and MAP-HbD gain. CONCLUSIONS This novel cerebrovascular monitoring technique allows quantification of cerebral pressure passivity as MAP-HbD gain in premature infants. We show that high MAP-HbD gain is significantly associated with GM/IVH. The precise temporal and causal relationship between MAP-HbD gain and GM/IVH awaits further study.

Cerebral autoregulation in the first day after preterm birth: no evidence of association with systemic inflammation

“…Since the start of this clinical study, methodological reviews have indicated that it is better to use gain rather than coherence as a measure of CA, and only in measurements with significant coherence (1,32). Approximately half of our study population was lost in the application of this methodology.…”

“…We used Monte Carlo simulations to determine this cutoff (≥0.47 in VLF and ≥0.45 in LF (39)). In the subgroup of infants with significant coherence (i.e., impaired CA), gain was used to estimate the magnitude of impairment in CA (1,32).…”

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

“…Associations between the development of cerebral pathology and impairment of cerebrovascular autoregulation have been reported. Tsuji et al and O'Leary et al reported that dynamic autoregulation impairment was associated with an increased risk of developing GMH/IVH or PVL [6,41]. Alderliesten et al found a statistically significant correlation between regional cerebral oxygen saturation (rSO 2 ) and ABP, suggestive of impaired autoregulation, before the development of mild-to-moderate IVH.…”

“…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.…”

Cerebrovascular autoregulation among very low birth weight infants

“…That is, from descriptions of total cerebral blood flow responses to changes in BP over a minute or so in time, to the descriptions of the nearly continuous fluctuations in cerebral blood flow in response to nearly continuous changes in BP. Reports by Tsuji et al 7 and O'Leary et al 8 use frequency domain analysis to demonstrate that preterm infants can autoregulate cerebral blood flow, but that periods of pressure passivity are common and predispose to IVH.…”