Charlamaine Parkinson

Cerebrovascular autoregulation and neurologic injury in neonatal hypoxic-ischemic encephalopathy.

Background:Neonates with hypoxic–ischemic encephalopathy (HIE) are at risk of cerebral blood flow dysregulation. Our objective was to describe the relationship between autoregulation and neurologic injury in HIE.Methods:Neonates with HIE had autoregulation monitoring with the hemoglobin volume index (HVx) during therapeutic hypothermia, rewarming, and the first 6 h of normothermia. The 5-mm Hg range of mean arterial blood pressure (MAP) with best vasoreactivity (MAPOPT) was identified. The percentage of time spent with MAP below MAPOPT and deviation in MAP from MAPOPT were measured. Neonates received brain magnetic resonance imaging (MRI) 3–7 d after treatment. MRIs were coded as no, mild, or moderate/severe injury in five regions.Results:HVx identified MAPOPT in 79% (19/24), 77% (17/22), and 86% (18/21) of the neonates during hypothermia, rewarming, and normothermia, respectively. Neonates with moderate/severe injury in paracentral gyri, white matter, basal ganglia, and thalamus spent a greater proportion of time with MAP below MAPOPT during rewarming than neonates with no or mild injury. Neonates with moderate/severe injury in paracentral gyri, basal ganglia, and thalamus had greater MAP deviation below MAPOPT during rewarming than neonates without injury.Conclusion:Maintaining MAP within or above MAPOPT may reduce the risk of neurologic injuries in neonatal HIE.

Apparent Diffusion Coefficient Scalars Correlate with Near-Infrared Spectroscopy Markers of Cerebrovascular Autoregulation in Neonates Cooled for Perinatal Hypoxic-Ischemic Injury

BACKGROUND AND PURPOSE: Neurologic morbidity remains high in neonates with perinatal hypoxic-ischemic injury despite therapeutic hypothermia. DTI provides qualitative and quantitative information about the microstructure of the brain, and a near-infrared spectroscopy index can assess cerebrovascular autoregulation. We hypothesized that lower ADC values would correlate with worse autoregulatory function. MATERIALS AND METHODS: Thirty-one neonates with hypoxic-ischemic injury were enrolled. ADC scalars were measured in 27 neonates (age range, 4–15 days) in the anterior and posterior centrum semiovale, basal ganglia, thalamus, posterior limb of the internal capsule, pons, and middle cerebellar peduncle on MRI obtained after completion of therapeutic hypothermia. The blood pressure range of each neonate with the most robust autoregulation was identified by using a near-infrared spectroscopy index. Autoregulatory function was measured by blood pressure deviation below the range with optimal autoregulation. RESULTS: In neonates who had MRI on day of life ≥10, lower ADC scalars in the posterior centrum semiovale (r = −0.87, P = .003, n = 9) and the posterior limb of the internal capsule (r = −0.68, P = .04, n = 9) correlated with blood pressure deviation below the range with optimal autoregulation during hypothermia. Lower ADC scalars in the basal ganglia correlated with worse autoregulation during rewarming (r = −0.71, P = .05, n = 8). CONCLUSIONS: Blood pressure deviation from the optimal autoregulatory range may be an early biomarker of injury in the posterior centrum semiovale, posterior limb of the internal capsule, and basal ganglia. Optimizing blood pressure to support autoregulation may decrease the risk of brain injury in cooled neonates with hypoxic-ischemic injury.

White-gray matter echogenicity ratio and resistive index: Sonographic bedside markers of cerebral hypoxic-ischemic injury/edema

Objective:Head ultrasonography (HUS) is a reliable and easy to perform bedside imaging technique that can give valuable information about degree of brain injury/edema after perinatal asphyxia in term neonates. The goals of our study were to determine whether semiquantitative markers such as standardized white matter/gray matter (WM/GM) echogenicity ratio and resistive index (RI) value measured by HUS differs between asphyxiated term neonates and healthy controls.Study Design:Thirty-one carefully selected term neonates who suffered from perinatal hypoxic–ischemic encephalopathy (HIE) were included in the study. The ratio of the WM/GM echogenicity of the cingulate gyrus was calculated. In addition, the RI value was measured in the anterior cerebral artery. US scalars were compared with 11 healthy neonates.Result:WM/GM ratio is significantly increased and RI value significantly decreased in asphyxiated term neonates compared with healthy subjects.Conclusion:WM/GM ratio and RI value allows discriminating between asphyxiated neonates and healthy subjects. These US scalars may serve as valuable, easy to acquire semiquantitative bedside markers of brain HIE, when magnetic resonance imaging is unavailable or cannot be performed in the acute setting.

Optimizing Cerebral Autoregulation May Decrease Neonatal Regional Hypoxic-Ischemic Brain Injury.

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 function (MAPOPT). Blood pressure deviation from MAPOPT was correlated with brain injury on MRI after adjusting for the effects of arterial carbon dioxide, vasopressors, seizures, and birth asphyxia severity. Results: Blood pressure deviation from MAPOPT related to neurologic injury in several regions independent of birth asphyxia severity. Greater duration and deviation of blood pressure below MAPOPT were associated with greater injury in the paracentral gyri and white matter. Blood pressure within MAPOPT related to lesser injury in the white matter, putamen and globus pallidus, and brain stem. Finally, blood pressures that exceeded MAPOPT were associated with reduced injury in the paracentral gyri. Conclusions: Blood pressure deviation from optimal autoregulatory vasoreactivity was associated with MRI markers of brain injury that, in many regions, were independent of the initial birth asphyxia. Targeting hemodynamic ranges to optimize autoregulation has potential as an adjunctive therapy to hypothermia for HIE.

Communication Challenges in Neonatal Encephalopathy

BACKGROUND: Families must process complex information related to neonatal encephalopathy and therapeutic hypothermia. METHODS: In this mixed methods study, semi-structured interviews were performed with parents whose infants were enrolled in an existing longitudinal cohort study of therapeutic hypothermia between 2011 and 2014. RESULTS: Thematic saturation was achieved after 20 interviews. Parental experience of communicating with clinicians was characterized by 3 principle themes. Theme 1 highlighted that a fragmented communication process mirrored the chaotic maternal and neonatal course. Parents often received key information about neonatal encephalopathy and therapeutic hypothermia from maternal clinicians. Infant medical information was often given to 1 family member (60%), who felt burdened by the responsibility to relay that information to others. Families universally valued the role of the bedside nurse, who was perceived as the primary source of communication for most (75%) families. Theme 2 encompassed the challenges of discussing the complex therapy of therapeutic hypothermia: families appreciated clinicians who used lay language and provided written material, and they often felt overwhelmed by technical information that made it hard to understand the “big picture” of their infant’s medical course. Theme 3 involved the uncertain prognosis after neonatal encephalopathy. Parents appreciated specific expectations about their infant’s long-term development, and experienced long-term distress about prognostic uncertainty. CONCLUSIONS: Communicating complex and large volumes of information in the midst of perinatal crisis presents inherent challenges for both clinicians and families. We identified an actionable set of communication challenges that can be addressed with targeted interventions.

Sex-specific associations between cerebrovascular blood pressure autoregulation and cardiopulmonary injury in neonatal encephalopathy and therapeutic hypothermia.

Background: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.Methods: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 measured associations between MAP relative to MAPOPT and indicators of cardiopulmonary injury (duration of mechanical respiratory support and administration of inhaled nitric oxide (iNO), milrinone, or steroids).Results:We identified associations between cerebrovascular autoregulation and cardiopulmonary injury that were often sex-specific. Greater MAP deviation above MAPOPT was associated with shorter duration of intubation in boys but longer ventilatory support in girls. Greater MAP deviation below MAPOPT related to longer intensive care stay in boys. Milrinone was associated with greater MAP deviation below MAPOPT in girls.Conclusion:MAP deviation from MAPOPT may relate to cardiopulmonary injury after neonatal encephalopathy, and sex may modulate this relationship. Whereas MAP above MAPOPT may protect the brain and lungs in boys, it may be related to cardiopulmonary injury in girls. Future studies are needed to characterize the role of sex in these associations.

Relationships between cerebral autoregulation and markers of kidney and liver injury in neonatal encephalopathy and therapeutic hypothermia

Objective:We studied whether cerebral blood pressure autoregulation and kidney and liver injuries are associated in neonatal encephalopathy (NE).Study design:We monitored autoregulation of 75 newborns who received hypothermia for NE in the neonatal intensive care unit to identify the mean arterial blood pressure with optimized autoregulation (MAPOPT). Autoregulation parameters and creatinine, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were analyzed using adjusted regression models.Results:Greater time with blood pressure within MAPOPT during hypothermia was associated with lower creatinine in girls. Blood pressure below MAPOPT related to higher ALT and AST during normothermia in all neonates and boys. The opposite occurred in rewarming when more time with blood pressure above MAPOPT related to higher AST.Conclusions:Blood pressures that optimize cerebral autoregulation may support the kidneys. Blood pressures below MAPOPT and liver injury during normothermia are associated. The relationship between MAPOPT and AST during rewarming requires further study.

Transfontanellar duplex brain ultrasonography resistive indices as a prognostic tool in neonatal hypoxic-ischemic encephalopathy before and after treatment with therapeutic hypothermia

Objective:Prior to therapeutic hypothermia (that is, cooling), transfontanellar duplex brain sonography resistive indices (RI) were studied as a bedside non-invasive measures of cerebral hemodynamics in neonates who suffered from hypoxic-ischemic encephalopathy (HIE). We compared pre- and post-cooling RI values and examined the relationships between RI values and specific long-term neurodevelopmental outcomes.Study Design:Transfontanellar duplex brain sonography, including RI, were obtained for 28 neonates prior to cooling and for 20 neonates following cooling. All RI values were sampled in the anterior cerebral artery at the beginning of each ultrasound study. Neurodevelopmental assessment was conducted between ages 20–32 months with the Mullen Scale of Early Learning. The relationships between pre- and post-cooling RI and cognitive and motor outcomes were studied.Result:Neonates with RI values <0.60 prior to and following cooling were more likely to die or have severe neurodevelopmental disability by ages 20–32 months than those with RI>0.60. Lower RI values were associated with specific neurodevelopmental deficits in motor skill attainment.Conclusion:Pre- and post-cooling transfontanellar duplex brain sonography RI values may be a useful prognostic tool, in conjunction with other clinical information, for neonates diagnosed with HIE. The results of this study suggest that further study of the prognostic value of RI values for short- and long-term outcomes is warranted.

Parent Experience of Neonatal Encephalopathy: The Need for Family-Centered Outcomes

We aimed to characterize the parent experience of caring for an infant with neonatal encephalopathy. In this mixed-methods study, we performed semistructured interviews with parents whose infants were enrolled in an existing longitudinal cohort study of therapeutic hypothermia between 2011 and 2014. Thematic saturation was achieved after 20 interviews. Parent experience of caring for a child with neonatal encephalopathy was characterized by 3 principal themes. Theme 1: Many families described cumulative loss and grief throughout the perinatal crisis, critical neonatal course, and subsequent missed developmental milestones. Theme 2: Families experienced entangled infant and broader family interests. Theme 3: Parents evolved into and found meaning in their role as an advocate. These data offer insight into the lived experience of parenting an infant with neonatal encephalopathy. Primary data from parents can serve as a useful framework to guide the development and interpretation of parent-centered outcomes.

EEG Monitoring Technique Influences the Management of Hypoxic-Ischemic Seizures in Neonates Undergoing Therapeutic Hypothermia.

Electroencephalogram (EEG) monitoring techniques for neonatal hypoxia-ischemia (HI) are evolving over time, and the specific type of EEG utilized could influence seizure diagnosis and management. We examined whether the type of EEG performed affected seizure treatment decisions (e.g., the choice and number of antiseizure drugs [ASDs]) in therapeutic hypothermia-treated neonates with HI from 2007 to 2015 in the Johns Hopkins Hospital Neonatal Intensive Care Unit. During this period, 3 different EEG monitoring protocols were utilized: Period 1 (2007-2009), single, brief conventional EEG (1 h duration) at a variable time during therapeutic hypothermia treatment, i.e., ordered when a seizure was suspected; Period 2 (2009-2013), single, brief conventional EEG followed by amplitude-integrated EEG for the duration of therapeutic hypothermia treatment and another brief conventional EEG after rewarming; and Period 3 (2014-2015), continuous video-EEG (cEEG) for the duration of therapeutic hypothermia treatment (72 h) plus for an additional 12 h during and after rewarming. One hundred and sixty-two newborns were included in this retrospective cohort study. As a function of the type and duration of EEG monitoring, we assessed the risk (likelihood) of receiving no ASD, at least 1 ASD, or ≥2 ASDs. We found that the risk of a neonate being prescribed an ASD was 46% less during Period 3 (cEEG) than during Period 1 (brief conventional EEG only) (95% CI 6-69%, p = 0.03). After adjusting for initial EEG and MRI results, compared with Period 1, there was a 38% lower risk of receiving an ASD during Period 2 (95% CI: 9-58%, p = 0.02) and a 67% lower risk during Period 3 (95% CI: 23-86%, p = 0.01). The risk ratio of receiving ≥2 ASDs was not significantly different across the 3 periods. In conclusion, in addition to the higher sensitivity and specificity of continuous video-EEG monitoring, fewer infants are prescribed an ASD when undergoing continuous forms of EEG monitoring (aEEG or cEEG) than those receiving conventional EEG. We recommend that use of continuous video-EEG be considered whenever possible, both to treat seizures more specifically and to avoid overtreatment.