Exploratory Assessment of the Relationship Between Hemoglobin Volume Phase Index, Magnetic Resonance Imaging, and Functional Outcome in Neonates with Hypoxic–Ischemic Encephalopathy

Published on Aug 1, 2021in Neurocritical Care3.21
· DOI :10.1007/S12028-020-01150-8
Penny Glass17
Estimated H-index: 17
Background/objective Near-infrared spectroscopy (NIRS)-based measures of cerebral autoregulation (CAR) can potentially identify neonates with hypoxic-ischemic encephalopathy (HIE) who are at greatest risk of irreversible brain injury. However, modest predictive abilities have precluded previously described metrics from entering clinical care. We previously validated a novel autoregulation metric in a piglet model of induced hypotension called the hemoglobin volume phase index (HVP). The objective of this study was to evaluate the clinical ability of the HVP to predict adverse outcomes neonates with HIE. Methods This is a prospective study of neonates with HIE who underwent therapeutic hypothermia (TH) at a level 4 neonatal intensive care unit (NICU). Continuous cerebral NIRS and mean arterial blood pressure (MAP) from indwelling arterial catheters were measured during TH and through rewarming. Multivariate autoregressive process was used to calculate the coherence between MAP and the sum total of the oxy- and deoxygenated Hb densities (HbT), a surrogate measure of cerebral blood volume (CBV). The HVP was calculated as the cosine-transformed phase shift at the frequency of maximal MAP-HbT coherence. Brain injury was assessed by neonatal magnetic resonance imaging (MRI), and developmental outcomes were assessed by the Bayley Scales of Infant Development (BSID-III) at 15-30 months. The ability of the HVP to predict (a) death or severe brain injury by MRI and (b) death or significant developmental delay was assessed using logistic regression analyses. Results In total, 50 neonates with moderate or severe HIE were monitored. Median HVP was higher, representing more dysfunctional autoregulation, in infants who had adverse outcomes. After adjusting for sex and encephalopathy grade at presentation, HVP at 21-24 and 24-27 h of life predicted death or brain injury by MRI (21-24 h: OR 8.8, p = 0.037; 24-27 h: OR 31, p = 0.011) and death or developmental delay at 15-30 months (21-24 h: OR 11.8, p = 0.05; 24-27 h: OR 15, p = 0.035). Conclusions Based on this pilot study of neonates with HIE, HVP merits further study as an indicator of death or severe brain injury on neonatal MRI and neurodevelopmental delay in early childhood. Larger studies are warranted for further clinical validation of the HVP to evaluate cerebral autoregulation following HIE.
Abstract Background Near infrared spectroscopy (NIRS) derived hemoglobin difference (HbD: oxygenated [HbO2] – reduced hemoglobin [Hb]) and total hemoglobin (HbT: HbO2+Hb) have been used as surrogate measures of cerebral blood flow and volume, respectively. Statistically, a lack of HbD-blood pressure (BP) or negative HbT-BP association is regarded as a state of intact cerebral pressure autoregulation (CPA). In contrast, a co-variation of HbD/HbT and systemic blood pressure (BP) in the same direct...
#2Kenneth Martin Brady (BCM: Baylor College of Medicine)H-Index: 37
Last. Jennifer K. Lee (JHUSOM: Johns Hopkins University School of Medicine)H-Index: 25
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INTRODUCTION: The optimal method to detect impairments in cerebrovascular pressure autoregulation in neonates with hypoxic-ischemic encephalopathy (HIE) is unclear. Improving autoregulation monitoring methods would significantly advance neonatal neurocritical care. METHODS: We tested several mathematical algorithms from the frequency and time domains in a piglet model of HIE, hypothermia, and hypotension. We used laser Doppler flowmetry and induced hypotension to delineate the gold standard lowe...
#1Lina F. Chalak (UTSW: University of Texas Southwestern Medical Center)H-Index: 25
#2Fenghua Tian (UTA: University of Texas at Arlington)H-Index: 24
Last. Rong Zhang (UTSW: University of Texas Southwestern Medical Center)H-Index: 56
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Birth asphyxia constitutes a major global public health burden for millions of infants, despite hypothermia therapy. There is a critical need for real time surrogate markers of therapeutic success, to aid in patient selection and/or modification of interventions in neonatal encephalopathy (NE). This is a proof of concept study aiming to quantify neurovascular coupling (NVC) using wavelet analysis of the dynamic coherence between amplitude-integrated electroencephalography (aEEG) and near-infrare...
#1Lina F. Chalak (UTSW: University of Texas Southwestern Medical Center)H-Index: 25
#2Rong ZhangH-Index: 56
Neonatal encephalopathy (NE) resulting from birth asphyxia constitutes a major global public health burden for millions of infants every year, and despite therapeutic hypothermia, half of these neonat
#1Raul Chavez-Valdez (Johns Hopkins University)H-Index: 18
#2Matthew O’Connor (Johns Hopkins University)H-Index: 3
Last. Jennifer K. Lee (Johns Hopkins University)H-Index: 25
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Cardiopulmonary injury is common in neonatal encephalopathy, but the link with cerebrovascular dysfunction is unknown. We hypothesized that alterations of cerebral autoregulation are associated with cardiopulmonary injury in neonates treated with therapeutic hypothermia (TH) for neonatal encephalopathy. The cerebral hemoglobin volume index (HVx) from near-infrared spectroscopy was used to identify the mean arterial blood pressure (MAP) with optimal autoregulatory vasoreactivity (MAPOPT). We meas...
#1Jennifer K. Lee (Johns Hopkins University)H-Index: 25
#2Andrea PorettiH-Index: 32
Last. Aylin Tekes (Johns Hopkins University)H-Index: 27
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Background: Therapeutic hypothermia provides incomplete neuroprotection for neonatal hypoxic-ischemic encephalopathy (HIE). We examined whether hemodynamic goals that support autoregulation are associated with decreased brain injury and whether these relationships are affected by birth asphyxia or vary by anatomic region. Methods: Neonates cooled for HIE received near-infrared spectroscopy autoregulation monitoring to identify the mean arterial blood pressure with optimized autoregulatory functi...
#1Derek M. Nusbaum (BCM: Baylor College of Medicine)H-Index: 5
#2Kenneth Martin Brady (BCM: Baylor College of Medicine)H-Index: 37
Last. Ronald B. Easley (BCM: Baylor College of Medicine)H-Index: 11
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Objectives: In the present study, our objective was to determine if hypercarbia would alter cerebral blood flow (CBF) autoregulation and reduce the ability of cerebrovascular reactivity monitoring to identify the lower limit of cerebrovascular autoregulation (LLA).Methods: Anaesthetised juvenile pigs were assigned between two groups: normocarbia (control group, n = 10) or hypercarbia [high carbon dioxide (CO2) group, n = 8]. Normocarbia subjects were maintained with an arterial CO2 of 40 Torr, w...
#1Krithika Lingappan (BCM: Baylor College of Medicine)H-Index: 17
#2Jeffrey R. Kaiser (BCM: Baylor College of Medicine)H-Index: 20
Last. Alistair J. Gunn (University of Auckland)H-Index: 74
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Relationship between PCO 2 and unfavorable outcome in infants with moderate-to-severe hypoxic ischemic encephalopathy
This review highlights the influence of oxygen (O2) availability on cerebral blood flow (CBF). Evidence for reductions in O2 content (CaO2) rather than arterial O2 tension (PaO2) as the chief regulator of cerebral vasodilation, with deoxyhemoglobin as the primary O2 sensor and upstream response effector, is discussed. We review in vitro and in vivo data to summarize the molecular mechanisms underpinning CBF responses during changes in CaO2. We surmise that 1) during hypoxemic hypoxia in healthy ...
#1Fenghua Tian (UTA: University of Texas at Arlington)H-Index: 24
#2Takashi Tarumi (UTSW: University of Texas Southwestern Medical Center)H-Index: 28
Last. Lina F. ChalakH-Index: 25
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Cerebral autoregulation represents the physiological mechanisms that keep brain perfusion relatively constant in the face of changes in blood pressure and thus plays an essential role in normal brain function. This study assessed cerebral autoregulation in nine newborns with moderate-to-severe hypoxic–ischemic encephalopathy (HIE). These neonates received hypothermic therapy during the first 72 h of life while mean arterial pressure (MAP) and cerebral tissue oxygenation saturation (SctO2) were c...
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