Impaired Right Ventricular Performance Is Associated with Adverse Outcome after Hypoxic Ischemic Encephalopathy

Cardiac biomarkers predict low right ventricle performance in neonatal encephalopathy

OBJECTIVE

Study the association between cardiac biomarkers and echocardiography parameters of ventricular performance in neonates with neonatal encephalopathy (NE).

METHODS

Prospective observational study (2016-2021) of neonates undergoing therapeutic hypothermia (TH). Neonates with brain injury had repeated echocardiography and biomarkers measurements on day of life (DOL) 2, 3, 4, and 10. Pearson correlation and generalized linear mixed effect models were used to account for repeated measurements. Receiver operating characteristic curves were constructed to assess sensitivity/specificity.

RESULTS

56 neonates had 128 measurements. Creatine Kinase (CK) and cardiac troponin-I (CTn-I) were associated with right ventricular (RV) function. A CK of 1961 U/L and a CTn-I of 91 ng/L identified low Tricuspid Annular Plane Systolic Excursion (<7 mm) with sensitivities of 93% and 79%, and specificities of 55% and 74%, respectively.

CONCLUSIONS

Elevated CK and CTn-I were associated with decreased RV performance. Trending these markers can be used to suspect altered RV function and may flag optimal timing for evaluation(s) by echocardiography during TH.

Predictive model of neurodevelopmental outcome in neonatal hypoxic ischemic encephalopathy

OBJECTIVES

To build an early, prognostic model for adverse outcome in infants with hypoxic ischemic encephalopathy (HIE) receiving therapeutic hypothermia (TH) based on brain magnetic resonance images (MRI), electrophysiological tests and clinical assessments were performed during the first 5 days of life.

METHODS

Retrospective study of 182 neonates with HIE and managed with TH. The predominant pattern of HIE brain injury on MRI performed following cooling was scored by neuroradiologists. The electroencephalogram (EEG) background and evoked potential (EP) response, were analyzed. Area under the curve (AUC) of these tools for adverse outcome including death and/or moderate disabilities using the Bayley-III at 36 months were calculated. A stepwise model approach was used to reach the final most efficient predictive model.

RESULTS

Of 182 neonates, 99 were male (54.4 %), with median gestational age of 39 weeks (IQR 38-40) and median weight of 3.3 kg (IQR 2.9-3.7). On admission, 47 (26 %), 104 (57 %) and 31(17 %) neonates presented with mild, moderate and severe encephalopathy respectively. In multivariate analysis of 129 infants who received all prognostic modalities, the predictive value of a model of EEG plus MRI, AUC = 84 %) is equivalent to models of EEG plus MRI with added EP and clinical assessment at discharge (AUC = 84 and 85 % respectively).

CONCLUSION

In the era of cooling for neonatal HIE, the combination of EEG background and MRI during the first few days of life, provide an objective and highly reliable model for prediction of death and long-term disabilities.

Neonatal Shock: Current Dilemmas and Future Research Avenues

Neonatal shock presents a complex clinical challenge and is one of the leading causes of mortality. Traditionally, neonatal shock is equated to hypotension, and therapeutics are often initiated based on low blood pressure (BP) values alone. This fails to address the underlying goal of optimizing the tissue perfusion resulting in both over- and under-treatment of neonatal shock. Also, what defines a normal BP in neonates is still a contentious topic. Further, the most appropriate way of measuring BP in neonates with shock is still debated. Shock secondary to transient circulatory instability and patent ductus arteriosus, conditions that are unique to preterm neonates, have not been researched adequately. Treatment of myocardial dysfunction secondary to perinatal asphyxia, a leading cause of neonatal mortality, is still a conundrum. Quite similarly, there are only a handful of controlled trials evaluating therapeutics in some of the other commonly encountered conditions, namely, septic shock and hypoperfusion secondary to pulmonary hypertension. Even the universally practiced intervention of volume expansion with crystalloid boluses in shock is not backed by high-certainty evidence in neonates. Though the diagnostic modalities of functional echocardiography and near-infrared spectroscopy have aided greatly in the management of neonatal shock in recent years, these have not been proven to be associated with improved critical clinical outcomes such as mortality and major brain injury. To conclude, neonatologists often rely on limited evidence, mostly anecdotal, when treating neonatal shock. This review critically examines the current evidence with respect to various aspects of neonatal shock with an objective to identify the lacunae in the literature that may fuel future research, eventually paving the way to efficacious, safe and evidence-based clinical practice.

Retrospective study of left and right ventricular strain mechanics among neonates undergoing therapeutic hypothermia for neonatal encephalopathy

PURPOSE

Early diagnosis of impaired myocardial function and timely therapeutic hypothermia is vital among patients with Neonatal Encephalopathy (NE). Traditional markers of myocardial function (Left Ventricular Ejection Fraction (LV EF) & LV Fractional Shortening (LV FS) can be variably reduced. Speckle tracking echocardiography (STE) is a more sensitive marker for impairment but remains inadequately studied in this patient population.

METHODS

A retrospective study of neonates who underwent therapeutic hypothermia (TH) for NE from 2009 to2020 were matched 1:1 with normal neonates with normal echocardiograms performed for indications other than NE. Matching was based on gestational age, birth weight, days of age, and sex. Left ventricular 4 Chamber (4Ch) strain, right ventricular 4 Chamber (RV 4Ch), and RV free wall strain (RV FWS) were measured offline using vendor independent strain software (TomTec, GMBH, Munich, Germany).

RESULTS

Ninety pairs of NE patients and controls were studied. Compared to controls, RV 4Ch strain (-17.3 % vs. -19.6 %), RV FWS (-18.8 % vs. -21.9 %), and RV fractional area change (FAC) (35 % vs. 37 %) were lower in NE cases (all p < 0.001), while differences in LV 4Ch strain, LV EF, and LV FS did not reach statistical significance. Moderate/severe NE (72 %) was associated with lower LV 4Ch strain compared to mild NE (-22.2 %/-19.3 % vs. -25.4 %, p = 0.004). RV 4Ch strain (-14.9 % vs. -18.8 %, p = 0.020) and RV FAC (27 % vs. 36 %, p = 0.006) were lower in severe NE compared to mild NE. Lower LV 4Ch was associated with need for chest compressions (-18.5 % vs. -23.3 %), epinephrine at delivery (-19.3 % vs. -23.4 %), and decreased survival to discharge (-15.9 % vs. -22.7 %).

CONCLUSIONS

RV and LV strain mechanics are impaired in NE patients. Lower RV Strain and LV 4Ch strain were associated with need for increased medical support and decreased survival to discharge.

Impact of persistent pulmonary hypertension on cerebral oxygenation in infants with neonatal encephalopathy

BACKGROUND

Persistent pulmonary hypertension of the newborn (PPHN) affects systemic oxygenation and may worsen brain injury in infants with neonatal encephalopathy (NE). Evidence suggests that higher cerebral regional oxygenation (crSO2) indicates derangement in cerebral autoregulation, energy metabolism, and blood flow following NE. Our aim was to evaluate the impact of PPHN on crSO2, in infants with NE treated with therapeutic hypothermia (TH).

METHODS

We retrospectively evaluated infants with NE and PPHN vs without PPHN, between 2018-2022. Linear regression analysis was performed to evaluate the impact of PPHN on crSO2 and total MRI score, adjusted for perinatal factors.

RESULTS

164 infants were analyzed, including 19(12%) with PPHN and 145(88%) without. PPHN-infants had significantly higher crSO2 during rewarming and post-rewarming compared to non-PPHN infants (87 ± 6 vs 80 ± 6, p = 0.001; 87 ± 5 vs 80 ± 7, p = 0.008, respectively), and a significantly higher total MRI score [7(2-19) vs 1(0-3), p < 0.001]. PPHN was significantly associated with higher crSO2 during rewarming (b = 6.21, 95% CI 2.37-10.04, p = 0.002) and post-rewarming (b = 8.60, 95% CI 2.28-14.91, p = 0.009), and total MRI score (b = 7.42, 95% CI 4.88-9.95, p < 0.001).

CONCLUSIONS

PPHN was associated with higher crSO2 during and after rewarming, and worse brain MRI score, indicating a significant impact of PPHN on brain injury in infants with NE undergoing TH.

IMPACT

Cerebral oxygenation was significantly higher in infants with neonatal encephalopathy (NE) and persistent pulmonary hypertension (PPHN) compared to infants without PPHN, during the rewarming and post-rewarming periods of therapeutic hypothermia (TH). PPHN is associated with brain injury in infants with NE undergoing TH. In infants with NE and PPHN, monitoring of cerebral oxygenation would help detect infants at higher risk of adverse outcomes.

Cardiac function at follow-up in infants treated with therapeutic hypothermia for neonatal hypoxic-ischemic encephalopathy

BACKGROUND

Compromised myocardial function and persistent elevated pulmonary vascular resistance are common among neonates treated with therapeutic hypothermia (TH) for hypoxic-ischemic encephalopathy (HIE). There is a lack of data regarding persistence of cardiac alterations after discharge from the neonatal intensive care unit (NICU).

METHODS

We assessed cardiovascular profiles after NICU discharge. Echocardiogram data, including speckle-tracking echocardiography (STE), were extracted from the latest outpatient scan. Data were compared by initial amplitude-integrated encephalography (aEEG) profiles on admission [normal vs. abnormal].

RESULTS

In total, 70 (19%) neonates had a follow-up echocardiogram (22 with initial normal aEEG, 48 with abnormal aEEG). Age at follow-up was similar between the two groups (6.2 vs. 7.7 months, [p = 0.08]). Neonates with an initially abnormal aEEG showed more negative Right Ventricle (RV)-peak global longitudinal strain (-28.2 vs. -26.0%, [p = 0.02]), RV-peak free wall longitudinal strain rate (-1.24 vs. -1.10 [1/second], [p = 0.01]), and RV-peak free wall longitudinal strain rate (-1.50 vs. -1.27 [1/second], [p = 0.001]). These associations remained after multilinear regression analysis, indicating persistent enhanced RV contraction in the abnormal aEEG group.

CONCLUSION

Neonates with initial abnormal aEEG profiles exhibited increased RV contraction after NICU discharge. Future studies should explore long-term cardiovascular follow-up of neonates with HIE, beyond the perinatal period.

IMPACT

What is the key message of your article? Cardiac performance in hypoxic ischemic encephalopathy is linked to adverse outcomes. Survivors with an abnormal aEEG at admission showed increased right ventricular contractility at follow-up, possibly related to an adverse adaptation to the initial insult. What does it add to the existing literature? This study offers insights into long-term cardiovascular outcomes in neonates with HIE, focusing on the link between initial aEEG abnormalities and later RV function. What is the impact? The findings underscore the importance of early cardiovascular assessments and monitoring in neonates undergoing TH for HIE, potentially guiding future follow-up protocols.

Association of Right Ventricular Dysfunction with Risk of Neurodevelopmental Impairment in Infants with Pulmonary Hypertension

(1) Background: Pulmonary hypertension (PH) increases pulmonary vascular resistance and right ventricular (RV) afterload. Assessment of RV systolic function in PH using RV fractional area change (RV FAC) as a marker directly correlates with mortality and the need for extracorporeal membrane oxygenation (ECMO). However, few studies have assessed neurodevelopmental outcomes. We hypothesize that cardiac RV systolic dysfunction with lower RV FAC is associated with worse neurodevelopmental impairment (NI). (2) Methods: Retrospective study of 42 subjects with PH to evaluate neurodevelopmental outcomes in the first two years of life based on (i) subjective assessment of RV systolic function and (ii) RV FAC, a specific echocardiographic marker for RV function. (3) Results: Subjects from the initial study cohort (n = 135) with PH who had long-term follow-up were divided into RV dysfunction (study, n = 20) and non-RV dysfunction (control, n = 22) groups. RV FAC in the study vs. control group (0.18 vs. 0.25) was lower (p = 0.00017). There was no statistically significant difference in NI either with RV dysfunction or lower RV FAC. Although not significant, RV dysfunction was associated with longer mean duration of mechanical ventilation, time on ECMO, and length of stay. In the initial cohort (135), mortality was 16.3% and the percentage of NI was 62%. (4) Conclusions: Neonatal pulmonary hypertension is associated with a high degree of neurodevelopment impairment. Early RV systolic dysfunction, as identified by RV FAC, was not an optimal predictive biomarker for infants with PH and neurodevelopmental impairment.

Near-infrared spectroscopy for perioperative assessment and neonatal interventions

Perioperative applications of near-infrared spectroscopy (NIRS) to monitor regional tissue oxygenation and perfusion in cardiac and noncardiac surgery are of increasing interest in neonatal care. Complex neonatal surgery can impair adequate oxygen delivery and tissue oxygen consumption and increase the risk of neurodevelopmental delay. Coupled with conventional techniques, NIRS monitoring may enable targeted hemodynamic management of the circulation in both cardiac and noncardiac surgical procedures. In this narrative review, we discuss the application of perioperative NIRS in specific neonatal interventions, including surgical intervention for congenital heart defects, definitive closure of the patent ductus arteriosus, neurological and gastrointestinal disorders, and use of extracorporeal membrane oxygenation. We identified areas for future research within disease-specific indications and offer a roadmap to aid in developing evidence-based targeted diagnostic and management strategies in neonates. IMPACT: There is growing recognition that perioperative NIRS monitoring, used in conjunction with conventional monitoring, may provide critical hemodynamic information that either complements clinical impressions or delivers novel physiologic insight into the neonatal circulatory and perfusion pathways.

Echocardiography in the neonatal unit: current status and future prospects

INTRODUCTION

Traditionally echocardiography was used by pediatric cardiologists to diagnose congenital heart defects in neonates. Formalized neonatal hemodynamic fellowships have been established where neonatologists acquire advanced echocardiographic skills to gain anatomical, physiological, and hemodynamic information in real time and utilize this information in making a timely and accurate physiology-based clinical decision.

AREA COVERED

Differences between a comprehensive formal structural echocardiography, neonatologist performed targeted echocardiography and limited assessment on point-of-care-ultrasonography for specific indications have been covered. This article is focused at providing a comprehensive review of the status of echocardiography in the neonatal units, recent advancements and its future prospects in the neonatal intensive care units.

EXPERT OPINION

Comprehensive guidelines providing the scope of practice, a framework for training, and robust clinical governance process for the neonatologist performed targeted echocardiography have been established. In the last decade, echocardiography has emerged as essential vital bedside diagnostic tool in providing high-quality care to the sick infants in the neonatal units, and it has proved to improve the outcomes in neonates. It is now being considered as a modern hemodynamic monitoring tool. Advances in technology, machine learning, and application of artificial intelligence in applications of echocardiography seem promising adjunct tools for rapid assessment in emergency situations.

Targeted Neonatal Echocardiography in the Management of Neonatal Pulmonary Hypertension

Pulmonary hypertension (PH) in neonates, originating from a range of disease states with heterogeneous underlying pathophysiology, is associated with significant morbidity and mortality. Although the final common pathway is a state of high right ventricular afterload leading to compromised cardiac output, multiple hemodynamic phenotypes exist in acute and chronic PH, for which cardiorespiratory treatment strategies differ. Comprehensive appraisal of pulmonary pressure, pulmonary vascular resistance, cardiac function, pulmonary and systemic blood flow, and extrapulmonary shunts facilitates delivery of individualized cardiovascular therapies in affected newborns.

Challenges in clinical identification of right ventricular dysfunction in preterm infants with persistent pulmonary hypertension of the newborn

BACKGROUND

Right ventricular dysfunction, typically qualitatively diagnosed (Q-RVd) in preterm infants, requires echocardiography which is not always acutely available. We aimed to identify clinical indices of Q-RVd in very preterm infants (gestational age, GA <32 weeks) with persistent pulmonary hypertension of newborn (PPHN) and examine the reliability and validity of Q-RVd.

METHODS

Forty-seven infants with mean ± SD GA of 26.8 ± 2.7 weeks who had targeted neonatal echocardiography (TNE) ≤72 h old, during PPHN, were retrospectively studied. Three standard TNE clips were reviewed by two blinded assessors, and infants categorized as Q-RVd if moderate-severe RVd was diagnosed on ≥2 clips. Cardiopulmonary clinical indices at TNE and quantitative RV functional markers were compared between Q-RVd vs. no-RVd groups. Potential quantitative RVd definitions examined by classifying each measurement as "low" or "normal" using published data. Inter-rater agreement for Q-RVd assessed using Kappa statistics.

RESULTS

Mean age at TNE was 25.3 ± 20.4 h with Q-RVd diagnosed in 19(40 %) infants. Q-RVd group demonstrated higher peak oxygen requirements (96 ± 9 % vs. 84 ± 16 %, p < 0.01); however, no clinical parameters at TNE differentiated the groups. Quantitative measures were lower in Q-RVd patients, confirming classification validity. Among tested quantitative definitions, low RV stroke volume was associated with lower systolic blood pressure (41±7 vs. 47±9 mmHg, p = 0.02) and higher shock index (4.02±0.80 vs. 3.44±0.72, p = 0.02). Kappa for Q-RVd was 0.55 (95%CI 0.32-0.77).

CONCLUSIONS

The non-specific nature of clinical markers of RVd in preterm infants with PPHN necessitates echocardiographic diagnosis of RVd. Studies should examine prognostic relevance of RVd and establish outcome-based quantitative definitions in preterm infants.

Comorbidities and Late Outcomes in Neonatal Pulmonary Hypertension

Long-term outcomes of persistent pulmonary hypertension of newborn (PPHN) depend on disease severity, duration of ventilation, and associated anomalies. Congenital diaphragmatic hernia survivors may have respiratory morbidities and developmental delay. The presence of PPHN is associated with increased mortality in hypoxic-ischemic encephalopathy, though the effects on neurodevelopment are less clear. Preterm infants can develop pulmonary hypertension (PH) early in the postnatal course or later in the setting of bronchopulmonary dysplasia (BPD). BPD-PH is associated with higher mortality, particularly within the first year. Evidence suggests that both early and late PH in preterm infants are associated with neurodevelopmental impairment.

Asphyxia, Therapeutic Hypothermia, and Pulmonary Hypertension

Neonates with a perinatal hypoxic insult and subsequent neonatal encephalopathy are at risk of acute pulmonary hypertension (aPH) in the transitional period. The phenotypic contributors to aPH following perinatal asphyxia include a combination of hypoxic vasoconstriction of the pulmonary vascular bed, right heart dysfunction, and left heart dysfunction. Therapeutic hypothermia is the standard of care for neonates with moderate-to-severe hypoxic ischemic encephalopathy. This review summarizes the underlying risk factors, causes of aPH in neonates with perinatal asphyxia, discusses the unique phenotypical contributors to disease, and explores the impact of the initial insult and subsequent therapeutic hypothermia on aPH.

Guidelines and Recommendations for Targeted Neonatal Echocardiography and Cardiac Point-of-Care Ultrasound in the Neonatal Intensive Care Unit: An Update from the American Society of Echocardiography

Targeted neonatal echocardiography (TNE) involves the use of comprehensive echocardiography to appraise cardiovascular physiology and neonatal hemodynamics to enhance diagnostic and therapeutic precision in the neonatal intensive care unit. Since the last publication of guidelines for TNE in 2011, the field has matured through the development of formalized neonatal hemodynamics fellowships, clinical programs, and the expansion of scientific knowledge to further enhance clinical care. The most common indications for TNE include adjudication of hemodynamic significance of a patent ductus arteriosus, evaluation of acute and chronic pulmonary hypertension, evaluation of right and left ventricular systolic and/or diastolic function, and screening for pericardial effusions and/or malpositioned central catheters. Neonatal cardiac point-of-care ultrasound (cPOCUS) is a limited cardiovascular evaluation which may include line tip evaluation, identification of pericardial effusion and differentiation of hypovolemia from severe impairment in myocardial contractility in the hemodynamically unstable neonate. This document is the product of an American Society of Echocardiography task force composed of representatives from neonatology-hemodynamics, pediatric cardiology, pediatric cardiac sonography, and neonatology-cPOCUS. This document provides (1) guidance on the purpose and rationale for both TNE and cPOCUS, (2) an overview of the components of a standard TNE and cPOCUS evaluation, (3) disease and/or clinical scenario-based indications for TNE, (4) training and competency-based evaluative requirements for both TNE and cPOCUS, and (5) components of quality assurance. The writing group would like to acknowledge the contributions of Dr. Regan Giesinger who sadly passed during the final revisions phase of these guidelines. Her contributions to the field of neonatal hemodynamics were immense.

Cerebral Tissue Oxygen Saturation Measurements in Perinatal Asphyxia Cases Treated with Therapeutic Hypothermia

Cerebral tissue oxygen saturation (CrSO2) measured with near-infrared spectroscopy (NIRS) technology has recently become the subject of several research studies. The aim of this study was to investigate the diagnostic value of CrSO2 measurements in perinatal asphyxia (PA) cases. The study included a patient group of 42 PA cases, who were to be applied with therapeutic hypothermia (TH), and a control group of 42 healthy term newborns. PA cases were determined as moderate or severe encephalopathy (Sarnat score stage II or III) in clinical evaluation. In both groups, left (CrSO2L) and right (CrSO2R) NIRS measurements were taken for 10 minutes on the scalp. The arithmetic mean value of measurements was calculated and compared. The mean measurements were CrSO2R 67.38 ± 9.39 and CrSO2L 66.73 ± 7.76 in the patient group, and CrSO2R 80.28 ± 8.04 and CrSO2L 79.14 ± 8.49 in the control group. The mean CrSO2R and CrSO2L measurements of the patient group were statistically significantly lower than those of the control group (p < 0.001). In the Pearson correlation analysis, a significant correlation was determined in the patient group between cord blood gas pH and CrSO2R (r: 0.539, p < 0.001) and CrSO2L (r: 0.54, p < 0.001). For a cutoff value of CrSO2L ≤ 72%, the positive predictive value was 80 and the negative predictive value was 84.6. For a cutoff value of CrSO2R ≤ 74%, the positive predictive value was 79.5 and the negative predictive value was 82.5. Low CrSO2 measurements obtained with the NIRS method in PA cases to be applied with TH together with cord blood gas parameters can be considered a helpful parameter in diagnosis.

Left Ventricular Function and Dimensions Are Altered Early in Infants Developing Brain Injury in the Setting of Neonatal Encephalopathy

We evaluated the association between left cardiac 3-dimensional echocardiographic parameters and brain injury in a single-center prospective study of neonates with neonatal encephalopathy. On day 2 of life, neonates with brain injury had greater left ventricle end-diastolic and stroke volume but also greater peak global circumferential strain detected by 3-dimensional echocardiogram.

Cardiac Dysfunction in Neonatal HIE Is Associated with Increased Mortality and Brain Injury by MRI

OBJECTIVE

Describe the association between cardiac dysfunction and death or moderate-to-severe abnormalities on brain magnetic resonance imaging (MRI) in neonates undergoing therapeutic hypothermia for hypoxic ischemic encephalopathy (HIE).

STUDY DESIGN

Retrospective study in neonates with moderate or severe HIE undergoing therapeutic hypothermia between 2008 and 2017. Primary outcome was death or moderate-to-severe brain injury using the Barkovich score. Conventional and speckle-tracking echocardiography measures were extracted from available echocardiograms to quantify right (RV) and left (LV) ventricular functions.

RESULTS

A total of 166 newborns underwent therapeutic hypothermia of which 53 (36.5%) had echocardiography performed. Ten (19%) died prior to hospital discharge, and 11 (26%) had moderate-to-severe brain injury. There was no difference in chronologic age at echocardiography between the normal and adverse outcome groups (22 [±19] vs. 28 [±21] hours, p = 0.35). Cardiac findings in newborns with abnormal outcome included lower systolic and diastolic blood pressure (BP) at echocardiography (p = 0.004) and decreased tricuspid annular plane systolic excursion (a marker of RV systolic function; p = 0.01), while the ratio of systolic pulmonary artery (PA) pressure to systolic BP indicated isosystemic pressures (>2/3 systemic) in both groups. A multilogistic regression analysis, adjusting for weight and seizure status, indicated an association between abnormal outcome and LV function by longitudinal strain, as well as by ejection fraction.

CONCLUSION

Newborns who died or had moderate-to-severe brain injury had a higher incidence of cardiac dysfunction but similar PA pressures when compared with those who survived with mild or no MRI abnormalities.

KEY POINTS

· Newborns with HIE with functional LV/RV dysfunction are at risk for death or brain injury.. · All neonates with HIE had elevated pulmonary pressure, but neonates with poor outcome had RV dysfunction.. · When evaluating newborns with HIE by echocardiography, beyond estimation of pulmonary pressure, it is important to assess biventricular function..

Altered biventricular function in neonatal hypoxic-ischaemic encephalopathy: a case-control echocardiographic study

BACKGROUND

In newborns with hypoxic-ischaemic encephalopathy, more profound altered right and left ventricular function has been associated with mortality or brain injury. Mechanisms underlying cardiac dysfunction in this population are thought to be related to the persistence of increased pulmonary vascular resistance and myocardial ischaemia. We sought to compare cardiac function in newborns with hypoxic-ischaemic encephalopathy to controls using echocardiography.

METHODS

We did a retrospective case-control study with moderate or severe hypoxic-ischaemic encephalopathy between 2008 and 2017. Conventional and speckle-tracking echocardiography measures were extracted to quantify right and left ventricular systolic and diastolic function. Fifty-five newborns with hypoxic-ischaemic encephalopathy were compared to 28 controls.

RESULTS

Hypoxic-ischaemic encephalopathy newborns had higher estimated systolic pulmonary pressure (62.5 ± 15.0 versus 43.8 ± 17.3 mmHg, p < 0.0001) and higher systolic pulmonary artery pressure/systolic blood pressure ratio [101 ± 16 (iso-systemic) versus 71 ± 27 (2/3 systemic range) %, p < 0.0001]. Tricuspid annular plane systolic excursion was decreased (7.5 ± 2.2 versus 9.0 ± 1.4 mm, p = 0.002), E/e' increased (7.9 ± 3.3 versus 5.8 ± 2.0, p = 0.01), and right ventricle-myocardial performance index increased (68.1 ± 21.5 versus 47.8 ± 9.5, p = 0.0001) in hypoxic-ischaemic encephalopathy. Conventional markers of left ventricle systolic function were similar, but e' velocity (0.059 ± 0.019 versus 0.070 ± 0.01, p = 0.03) and left ventricle-myocardial performance index were statistically different (77.9 ± 26.2 versus 57.9 ± 11.2, p = 0.001). The hypoxic-ischaemic encephalopathy group had significantly altered right and left ventricular deformation parameters by speckle-tracking echocardiography. Those with decreased right ventricle-peak longitudinal strain were more likely to have depressed left ventricle-peak longitudinal strain.

CONCLUSION

Newborns with hypoxic-ischaemic encephalopathy have signs of increased pulmonary pressures and altered biventricular systolic and diastolic function.

Normative echocardiography data of myocardial adaptation to extrauterine life: a review of prospective studies

Recent research has increased focus and interest in characterizing the physiology of the transition circulation using echocardiography. Critique of published normative neonatal echocardiography data among healthy term neonates has not been performed. We have performed a comprehensive literature review using the key terms: cardiac adaptation, hemodynamics, neonatal transition, term newborns. Studies were included if they had reported echocardiography indices of cardiovascular function in the presence of maternal diabetes, intrauterine growth restricted newborns and prematurity and had a comparison group of healthy term newborns within first seven postnatal days. Sixteen published studies evaluating transitional circulation in healthy newborns were included. There was marked heterogeneity in the methodologies used; specifically, inconsistency in time of evaluation and imaging techniques used makes it challenging to determine specific trends of expected physiologic changes. Some studies revealed nomograms for echocardiography indices, though limitations persist in terms of sample size, number of reported parameters and consistency of measurement technique. A comprehensive standardized echocardiography framework which includes consistent techniques for assessment dimensions, function, blood flow, pulmonary/systemic vascular resistance, and shunts pattern is warranted to ensure consistency in the use of echocardiography to guide care of healthy and sick newborns.

Arterial pressure is not reflective of right ventricular function in neonates with hypoxic ischemic encephalopathy treated with therapeutic hypothermia

AIM

to evaluate the correlation of recovery of arterial pressure with physiological recovery among patients with hypoxic ischemic encephalopathy undergoing therapeutic hypothermia.

METHODS

At 24 h postnatal age, we compared 53 neonates of whom 22 (41%) were inotrope-treated to those untreated with cardiovascular medications.

RESULTS

Inotrope-treated patients had persistent severe right ventricular (RV) dysfunction and evidence of abnormal brain tissue oxygen delivery, despite recovered arterial pressure.

CONCLUSION

Arterial pressure is not reflective of RV function and the need for inotropic agents may be reflective of abnormal brain tissue oxygen delivery.

Time series analysis of non-invasive hemodynamic monitoring data in neonates with hypoxic-ischemic encephalopathy

Background and aims

Hemodynamic instability is common in neonates with hypoxic-ischemic encephalopathy (HIE) undergoing therapeutic hypothermia (TH). Rewarming is a critical period and non-invasive circulatory monitoring may help guide cardiovascular supportive therapy. The aim of the study was to provide a comprehensive analysis of cardiac function parameters during TH and its relation to neurodevelopmental outcome.

Methods

In a prospective, observational study, 26 neonates with moderate-severe HIE were enrolled, born between 2016 and 2019. A hemodynamic monitor based on electrical velocimetry (ICON, Osypka Medical GmbH, Berlin, Germany) was used. Heart rate (HR), stroke volume (SV), cardiac output (CO) data were recorded continuously throughout TH and rewarming. Neurological outcome was assessed at 2 years of age using the Bayley Scales of Infant Development II. edition. Favorable outcome was defined as >70 points on both the psychomotor and mental scales. Time-series analysis was used and features of cardiac function were described to perform logistic regression modeling for outcome prediction.

Results

Fourteen (54%) patients had favorable and 12 (46%) had adverse outcome. Data collection started from median [IQR] of 11.8 [7.0; 24.3] hours (h) of life and lasted until 84.0. [81.8; 87.0] h. During TH, the mean HR of the favorable outcome group was significantly lower than that of the adverse outcome group (86 ± 13/min vs. 104 ± 18/min, p = 0.01). During rewarming HR increased similarly in both groups. SV was unaffected by rewarming, and showed a slowly increasing trend. SV of the favorable outcome group was significantly higher compared to the adverse outcome group (1.55 ± 0.23 ml/kg vs. 1.29 ± 0.30 ml/kg, p = 0.035). In line with this, CO was similar in both groups (136 ± 27 ml/kg/min vs. 134 ± 36 ml/kg/min), and a significant 25% increase in CO was observed during rewarming. Based on multiple regression modeling, HR during TH was independently associated with neurological outcome (p = 0.023).

Conclusion

Based on continuous hemodynamic monitoring, patients with adverse outcome have lower SV and higher HR to achieve similar CO to patients with favorable outcome during TH. HR during hypothermia is independently associated with the neurodevelopmental outcome.

Comparative evaluation of approach to cardiovascular care in neonatal encephalopathy undergoing therapeutic hypothermia

OBJECTIVE

To analyze the association between cardiovascular care and adverse outcome in infants undergoing therapeutic hypothermia for neonatal encephalopathy (NE).

STUDY DESIGN

This was a retrospective cohort study of 176 infants with NE and hypotension, admitted to the SickKids Hospital (Center A, n = 86) or Semmelweis University (Center B, n = 90).

RESULT

The lowest systolic/diastolic blood pressures were comparable amongst centers; however, proportion of cardiovascular support was lower in Center A (51% vs 97% in Center B). Overall rate of death or abnormal MRI (adverse outcome) were comparable between centers, although pattern differed with more basal ganglia injury in Center B. A 24-hour longer duration of cardiovascular support increased the odds for adverse outcome by 14%.

CONCLUSION

We demonstrated that management of hemodynamic instability in infants with NE was markedly different in two high-volume NICUs and showed that longer duration of cardiovascular medication is an independent risk factor for adverse outcome.

Non-invasive continuous cardiac output monitoring in infants with hypoxic ischaemic encephalopathy

OBJECTIVE

To describe early, continuous, non-invasive measures of cardiac output (CO) and evolution over time in infants with hypoxic-ischaemic encephalopathy (HIE).

STUDY DESIGN

Prospective observational study of 44 infants with HIE (23 mild, 17 moderate, 4 severe) and 17 term controls. Infants with HIE had non-invasive CO monitoring (NICOM) continuously in the neonatal unit. Term controls had NICOM recorded at 6 and 24 h. A mixed-modelling approach was used to assess change in CO over time by group.

RESULTS

Infants with moderate HIE have significantly lower CO than the mild group at all timepoints (10.7 mls/kg/min lower, 95% CI:1.0,20.4, p = 0.03) which increases over time, driven by a gradual increase in stroke volume (SV). CO increased further during rewarming predominantly due to an increase in HR.

CONCLUSION

TH has a significant impact on HR but SV appears largely unaffected. NICOM may provide a non-invasive, continuous, low-cost alternative to monitoring CO in infants with HIE however further research is warranted.

Subclinical Left Ventricular Systolic Dysfunction due to Coronary Arterial Thrombosis in a Neonate with Hypoxic Ischemic Encephalopathy Undergoing Therapeutic Hypothermia

•

Routine clinical parameters are not reliable surrogates of “low cardiac output” in HIE.

•

TnECHO screening may identify subclinical myocardial dysfunction in neonates.

•

TH may positively modulate myocardial oxygen consumption in myocardial ischemia.

•

Rigorous echo training and collaboration with pediatric cardiology are imperative.

Association between multi-organ dysfunction and adverse outcome in infants with hypoxic ischemic encephalopathy

OBJECTIVE

To evaluate multi-organ dysfunction (MOD) in newborns treated with therapeutic hypothermia (TH) for hypoxic ischemic encephalopathy (HIE), and to compare MOD in those with normal/mild magnetic resonance imaging (MRI) findings to those with moderate to severe MRI findings or death.

STUDY DESIGN

Retrospective single-center observational study of infants treated with TH. A total of 16 parameters across 7 organ systems were analyzed. Primary outcome was death or moderate to severe brain injury on MRI.

RESULT

Of 157 infants treated with TH, 77% had ≥2 organ systems with dysfunction. The number of organ systems with dysfunction was strongly associated with death or moderate-to-severe brain injury (p < 0.0001). Hematologic (68%) and hepatic (65%) dysfunction were most common. Neurologic and renal dysfunction were most strongly associated with the primary outcome (OR 13.5 [6.1-29.8] and 11.2 [4.1-30.3], respectively), while pulmonary hypertension was not.

CONCLUSION

MOD is prevalent in infants undergoing TH for HIE, and the association between MOD and adverse outcomes may impact clinical care and counseling.

Hemodynamic changes and evaluation during hypoxic-ischemic encephalopathy and therapeutic hypothermia

Multiorgan damage is a hallmark of hypoxic-ischemic encephalopathy and cardiovascular and hemodynamic changes during asphyxia contribute significantly to the brain damage. The main insult to the heart is myocardial damage and associated ventricular dysfunction, which is manifested by reduced preload and afterload. The immature myocardium reacts to asphyxia by bradycardia and reduced contractile capacity. Pulmonary hypertension aggrevates cardiac dysfunction. Hypothermia is the only effective treatment for HIE but it may also affect the heart and peripheral vascular system leading to bradycardia and peripheral vasoconstriction. In fact, these effects might be cardioprotective also. Rewarming after hypothermia may increase the heart rate and cardiac metabolism, augmenting the cardiac output. Monitoring of patient with HIE during and after hypothermia is possible by using near-infrared spectroscopy, echocardiography and electrocardiography. Cerebral effects may be monitored by magnetic resonance imaging also. Management should include the physiological status of the patient and appropriate treatments, including inotropes, vasopressors or rarely fluid boluses. Dopamine should not be used unless absolutely necessary. Drugs like melatonin and magnesium are under investigation. All treatments should be evidence-based and targeted echocardiography should be used more often in these vulnerable infants.

A new physiologic-based integrated algorithm in the management of neonatal hemodynamic instability

Physiologic-based management of hemodynamic instability is proven to guide the logical selection of cardiovascular support and shorten the time to clinical recovery compared to an empiric approach that ignores the heterogeneity of the hemodynamic instability related mechanisms. In this report, we classified neonatal hemodynamic instability, circulatory shock, and degree of compensation into five physiologic categories, based on different phenotypes of blood pressure (BP), other clinical parameters, echocardiography markers, and oxygen indices. This approach is focused on hemodynamic instability in infants with normal cardiac anatomy.Conclusion: The management of hemodynamic instability is challenging due to the complexity of the pathophysiology; integrating different monitoring techniques is essential to understand the underlying pathophysiologic mechanisms and formulate a physiologic-based medical recommendation and approach. What is Known: • Physiologic-based assessment of hemodynamics leads to targeted and pathophysiologic-based medical recommendations. What is New: • Hemodynamic instability in neonates can be categorized according to the underlying mechanism into five main categories, based on blood pressure phenotypes, systemic vascular resistance, and myocardial performance. • The new classification helps with the targeted management and logical selection of cardiovascular support.

Neonatal Myocardial Ischemia-Reperfusion Injury: A Proposed Pathogenic Sequence in the Context of Maternal/Fetal Vascular Malperfusion and Paradoxical Embolism

BACKGROUND

Neonatal myocardial infarction (MI) in a structurally normal heart is frequently an obscure event that remains undiagnosed until autopsy. Causal attributions usually cite underlying maternal or fetal conditions. Refinement in understanding of pathogenic mechanisms underlying neonatal MI is key to advancements in diagnosis, prevention, treatments and prognosis.

OBJECTIVE

This study presents a 36-week gestational age female with perinatal asphyxia, congenital hemolytic anemia and umbilical vein thrombosis who sustained catastrophic MI with reperfusion injury; and it reviews pertinent literature.

RESULTS

We propose a pathogenic sequence that links maternal vascular malperfusion, fetal vascular malperfusion, hemolytic anemia, umbilical venous thrombosis, and paradoxical thromboemboli.

CONCLUSION

This case highlights the importance of placental examination in connecting complex neonatal events with adverse maternal/placental conditions. A high index of suspicion is essential for early diagnosis of neonatal MI.

Pathophysiology of Perinatal Asphyxia in Humans and Animal Models

Perinatal asphyxia is caused by lack of oxygen delivery (hypoxia) to end organs due to an hypoxemic or ischemic insult occurring in temporal proximity to labor (peripartum) or delivery (intrapartum). Hypoxic-ischemic encephalopathy is the clinical manifestation of hypoxic injury to the brain and is usually graded as mild, moderate, or severe. The search for useful biomarkers to precisely predict the severity of lesions in perinatal asphyxia and hypoxic-ischemic encephalopathy (HIE) is a field of increasing interest. As pathophysiology is not fully comprehended, the gold standard for treatment remains an active area of research. Hypothermia has proven to be an effective neuroprotective strategy and has been implemented in clinical routine. Current studies are exploring various add-on therapies, including erythropoietin, xenon, topiramate, melatonin, and stem cells. This review aims to perform an updated integration of the pathophysiological processes after perinatal asphyxia in humans and animal models to allow us to answer some questions and provide an interim update on progress in this field.

Effect of dexmedetomidine on heart rate in neonates with hypoxic ischemic encephalopathy undergoing therapeutic hypothermia

BACKGROUND

Sedation is recommended to optimize neuroprotection in neonates with hypoxic ischemic encephalopathy (HIE) undergoing therapeutic hypothermia (TH). Dexmedetomidine is an alternative agent to opioids, which are commonly used but have adverse effects. Both TH and dexmedetomidine can cause bradycardia. In this study, we describe our experience with dexmedetomidine and fentanyl in neonates undergoing TH for HIE, with a focus on heart rate (HR).

METHODS

We performed a retrospective chart review from 2011-2019 at a level IV NICU comparing sedation with dexmedetomidine (n = 14), fentanyl (n = 120), or both (n = 32) during TH for HIE. HR trends were compared based on sedation and gestational age. Neonates were included if they underwent TH and received sedation and were excluded if cooling was initiated past 24hours (h) from birth or if they required ECMO.

RESULTS

Of the 166 neonates included, 46 received dexmedetomidine, 14 as monotherapy and 32 in combination with fentanyl. Mean hourly HR from 12-36 h after birth was significantly lower for infants on dexmedetomidine versus fentanyl monotherapy (91±9 vs. 103±11 bpm, p < 0.002). Dexmedetomidine was decreased or discontinued in 22 (47.8%) neonates, most commonly due to inadequate sedation with a low HR. Lower gestational age was associated with higher HR but no significant difference in dexmedetomidine-related HR trends.

CONCLUSIONS

Despite an association with lower HR, dexmedetomidine may be successfully used in neonates with HIE undergoing TH. Implementation of a standardized protocol may facilitate dexmedetomidine titration in this population.

Neurodevelopmental outcome following hypoxic ischaemic encephalopathy and therapeutic hypothermia is related to right ventricular performance at 24-hour postnatal age

OBJECTIVE

Our aim was to determine whether right ventricular (RV) dysfunction at 24-hour postnatal age predicts adverse developmental outcome among patients with hypoxic ischaemic encephalopathy (HIE) undergoing therapeutic hypothermia (TH).

DESIGN

Neonates≥35 weeks with HIE/TH were enrolled in a physiological study in the neonatal period (n=46) and either died or underwent neurodevelopmental follow-up at 18 months (n=43). The primary outcome was a composite of death, diagnosis of cerebral palsy or any component of the Bayley Scores of Infant Development III<70. We hypothesised that tricuspid annulus plane systolic excursion (TAPSE) <6 mm and/or RV fractional area change (RV-FAC) <0.29 would predict adverse outcome.

RESULTS

Nine patients died and 34 patients were followed up at a mean age of 18.9±1.4 months. Both indices of RV systolic performance were abnormal in 15 (35%) patients, TAPSE <6 mm only was abnormal in 4 (9%) patients and RV-FAC <0.29 only was abnormal in 5 (12%) patients (19 had with normal RV function). Although similar at admission, neonates with RV dysfunction had higher cardiovascular and neurological illness severity by 24 hours than those without and severe MRI abnormalities (70% vs 53%, p=0.01) were more common. On logistic regression, TAPSE <6 mm (OR 3.6, 95% CI 1.2 to 10.1; p=0.017) and abnormal brain MRI [OR 21.7, 95% CI 1.4 to 336; p=0.028) were independently associated with adverse outcome. TAPSE <6 mm predicted outcome with a 91% sensitivity and 81% specificity.

CONCLUSIONS

The role of postnatal cardiovascular function on neurological outcomes among patients with HIE who receive TH merits further study. Quantitative measurement of RV function at 24 hours may provide an additional neurological prognostic tool.

Diastolic Dysfunction in Neonates With Hypoxic-Ischemic Encephalopathy During Therapeutic Hypothermia: A Tissue Doppler Study

Diastolic dysfunction often complicates myocardial ischemia with increased mortality rates. However, less is known about diastolic function after perinatal asphyxia in neonates with hypoxic-ischemic encephalopathy (HIE) during therapeutic hypothermia (TH) and rewarming.

AIM

The aim of this study was to assess diastolic function with tissue Doppler imaging (TDI) in neonates with moderate-severe HIE during TH and rewarming.

METHOD

Newborns at >36 weeks' gestation with moderate-severe HIE treated with TH were evaluated with targeted neonatal echocardiography (TNE), including TDI, within 24 h of TH initiation (T1), at 48-72 h of treatment (T2), and after rewarming (T3). These retrospective data were collected and compared with a control group of healthy babies at >36 weeks' gestation that was prospectively evaluated following the same protocol.

RESULTS

A total of 21 patients with HIE + TH and 15 controls were included in the study. Myocardial relaxation before the onset of biventricular filling was prolonged in the HIE + TH group during TH with significantly longer isovolumic relaxation time (IVRT') in the left ventricle (LV), the septum, and the right ventricle (RV). This was associated with slower RV early diastolic velocity (e') and prolonged filling on T1. Total isovolumic time (t-IVT; isovolumic contraction time [IVCT'] + IVRT') and myocardial performance index (MPI') were globally increased in asphyxiated neonates. All these differences persisted after correction for heart rate (HR) and normalized after rewarming. TDI parameters assessing late diastole (a' velocity or e'/a' and E/e' ratios) did not differ between groups.

CONCLUSION

TDI evaluation in our study demonstrated a pattern of early diastolic dysfunction during TH that normalized after rewarming, whereas late diastole seemed to be preserved. Our data also suggest a possible involvement of impaired twist/untwist motion and dyssynchrony. More studies are needed to investigate the impact and therapeutic implication of diastolic dysfunction in these babies, as well as to clarify the role of TH in these findings.

Comparative evaluation of echocardiography indices during the transition to extrauterine life between small and appropriate for gestational age infants

OBJECTIVES

To study changes in heart function and hemodynamics during the transitional period in small for gestational (SGA) infants and appropriate (AGA) healthier counterparts.

DESIGN

A hospital based prospective observational study was performed at a perinatal center. Echocardiograms were performed on the first postnatal day and again at 48 h age. Term SGA infants were compared with those AGA newborns matched for the GA and mode of delivery.

RESULTS

Eighteen SGA infants were compared with 18 AGA infants [gestation 38 ± 1.5 vs. 38 ± 1.2 weeks, p > 0.05 and birthweight 2331 ± 345 vs. 3332 ± 405 grams, p < 0.05, respectively]. Maternal weight and body mass index was higher among non-affected pregnancies, 61% infants were born vaginally, and no differences in cord blood pH at birth were noted. SGA infants had higher systolic and mean blood pressure at both time points, lower indices of right ventricular (RV) performance [TAPSE (tricuspid annular peak systolic excursion) 7.4 ± 2.8 vs. 9.3 ± 0.7 on day 1, 7.2 ± 2.8 vs. 9.2 ± 0.5 on day 2, p = 0.001], lower pulmonary acceleration time (PAAT) suggestive of elevated pulmonary vascular resistance [56.4 ± 10.5 vs. 65.7 ± 13.2 on day 1, 61.4 ± 12.5 vs. 71.5 ± 15.7 on day 2, p = 0.01] and higher left ventricular (LV) ejection fraction [62.1 ± 7.8 vs. 54.9 ± 5.5 on day 1, 61.9 ± 7.6 vs. 55.8 ± 4.9 on day 2, p = 0.003].

CONCLUSIONS

SGA infants had evidence of higher pulmonary vascular resistance, and lower RV performance during the postnatal transition. The relevance and impact of these changes to hemodynamic disease states during the postnatal transition requires prospective investigation.

Hemodynamic response to milrinone for refractory hypoxemia during therapeutic hypothermia for neonatal hypoxic ischemic encephalopathy

OBJECTIVE

Characterize the impact of milrinone on arterial pressure of neonates with persistent hypoxemic respiratory failure (HRF) and hypoxic ischemic encephalopathy (HIE) treated with inhaled nitric oxide and therapeutic hypothermia (TH).

STUDY DESIGN

Retrospective cohort study. Arterial pressure was assessed hourly for 24 h. The primary outcome was change in diastolic arterial pressure (DAP).

RESULTS

56 patients were included [(i) cases: HIE/TH who received milrinone (n = 9), (ii) Milrinone controls (n = 17), (iii) HIE controls (n = 30)]. Baseline demographics, severity of HRF and arterial pressure were comparable between groups. Only milrinone treated patients with HIE/TH had a marked drop in DAP in the first hour, which persisted for more than 12 h despite escalation in inotropes (p = 0.008).

CONCLUSION

Milrinone treated patients with HRF and HIE/TH develop profound reduction in DAP and require escalation of cardiovascular support. The risk benefit profile of milrinone should be considered and pharmacological studies are warranted to evaluate drug metabolism and clearance in this population.

Hemodynamic optimization for neonates with neonatal encephalopathy caused by a hypoxic ischemic event: Physiological and therapeutic considerations

Neonatal encephalopathy due to a hypoxic-ischemic event is commonly associated with cardiac dysfunction and acute pulmonary hypertension; both therapeutic hypothermia and rewarming modify loading conditions and blood flow. The pathophysiological contributors to disease are complex with a high degree of clinical overlap and traditional bedside measures used to assess circulatory adequacy have multiple confounders. Comprehensive, quantitative echocardiography may be used to delineate the relative contribution of lung parenchymal, pulmonary vascular, and cardiac disease to hypotension and/or hypoxemic respiratory failure. In this review, we provide a detailed overview of the contributors to hemodynamic instability following perinatal hypoxic-ischemic injury. Our proposed approach to therapy focuses on physiopathological considerations with interventions individualized to this potentially complex condition and considers the pharmacological idiosyncrasies, which may occur among neonates with NE presenting with multiorgan dysfunction while undergoing therapeutic hypothermia.

Clinical and echocardiography predictors of response to inhaled nitric oxide in hypoxemic term and near-term neonates

Approximately 40% of hypoxemic term/near-term neonates are nonresponders to inhaled nitric oxide (iNO). Phenotypic characterization of patients less likely to respond may improve diagnostic precision and therapeutic decisions. We conducted a retrospective cohort study of neonates born ≥35 weeks gestation with hypoxemia who received iNO in the first 72 h of life and classified them into responders and nonresponders according to changes in the fraction of inspired oxygen, saturations and/or arterial partial pressure of oxygen after 1 h of administration. Comprehensive targeted neonatal echocardiography (TnECHO) data were collected when performed up to 6 h prior or 24 h after iNO initiation. Descriptive statistics, univariate analysis, and binary logistic regression were used to compare the groups. There were 183 patients included (63% responders) and TnECHO was performed in 54 infants. The presence of lung disease, and particularly meconium aspiration syndrome (p = .004), was associated with nonresponse to iNO. Nonresponders were characterized by a higher need for rescue high-frequency ventilation (p < .001), longer duration of mechanical ventilation (p < .001), and need for oxygen support (p = .003). Pulmonary hypertension documented on TnECHO was present in 96.3% of the patients but there was no difference in frequency or severity of pulmonary hypertension, or rates of low cardiac output between the groups. Moderate-to-severe right ventricular systolic dysfunction (p > .05) and lower left ventricular strain (p < .05) were more likely in the nonresponder group. In summary, response to iNO is influenced by lung disease, choice of ventilation strategy, and perhaps underlying cardiovascular physiology. Prospective pre- and post-iNO echocardiography data may provide novel physiologic insights.

Impact of Acute and Chronic Hypoxia-Ischemia on the Transitional Circulation

The transition from intrauterine life to extrauterine existence encompasses significant cardiorespiratory adaptations. These include rapid lung aeration and increase in pulmonary blood flow (PBF). Perinatal asphyxia and fetal growth restriction can severely hamper this transition. Hypoxia is the common denominator in these 2 disease states, with the former characterized by acute insult and the latter by utero-placental insufficiency and a chronic hypoxemic state. Both may manifest as hemodynamic instability. In this review, we emphasize the role of physiologic-based cord clamping in supplementing PBF during transition. The critical role of lung aeration in initiating pulmonary gas exchange and increasing PBF is discussed. Physiologic studies in animal models have enabled greater understanding of the mechanisms and effects of various therapies on transitional circulation. With data from sheep models, we elaborate instrumentation for monitoring of cardiovascular and pulmonary physiology and discuss the combined effect of chest compressions and adrenaline in improving transition at birth. Lastly, physiologic adaptation influencing management in human neonatal cohorts with respect to cardiac and vascular impairments in hypoxic-ischemic encephalopathy and growth restriction is discussed. Impairments in right ventricular function and vascular mechanics hold the key to prognostication and understanding of therapeutic rationale in these critically ill cohorts. The right ventricle and pulmonary circulation seem to be especially affected and may be explored as therapeutic targets. The role of comprehensive assessments using targeted neonatal echocardiography as a longitudinal, reliable, and easily accessible tool, enabling precision medicine facilitating physiologically appropriate treatment choices, is discussed.

Outcomes of infants with hypoxic ischemic encephalopathy and persistent pulmonary hypertension of the newborn: results from three NICHD studies

OBJECTIVE

To determine the association of persistent pulmonary hypertension of the newborn (PPHN) with death or disability among infants with moderate or severe hypoxic ischemic encephalopathy (HIE) treated with therapeutic hypothermia.

METHODS

We compared infants with and without PPHN enrolled in the hypothermia arm from three randomized controlled trials (RCTs): Induced Hypothermia trial, "usual care" arm of Optimizing Cooling trial, and Late Hypothermia trial. Primary outcome was death or disability at 18-22 months adjusted for severity of HIE, center, and RCT.

RESULTS

Among 280 infants, 67 (24%) were diagnosed with PPHN. Among infants with and without PPHN, death or disability was 47% vs. 29% (adjusted OR: 1.65, 0.86-3.14) and death was 26% vs. 12% (adjusted OR: 2.04, 0.92-4.53), respectively.

CONCLUSIONS

PPHN in infants with moderate or severe HIE was not associated with a statistically significant increase in primary outcome. These results should be interpreted with caution given the limited sample size.

Cardiovascular management following hypoxic-ischemic encephalopathy in North America: need for physiologic consideration

BACKGROUND

Hypotension and hypoxemic respiratory failure are common among neonates with hypoxic-ischemic encephalopathy (HIE) undergoing therapeutic hypothermia (TH). Right ventricular (RV) dysfunction is associated with adverse neurodevelopment. Individualized management utilizing targeted neonatal echocardiography (TnECHO) may enhance care.

METHODS

We evaluated the influence of TnECHO programs on cardiovascular practices in HIE/TH patients utilizing a 77-item REDCap survey. Nominated representatives of TnECHO (n = 19) or non-TnECHO (n = 96) sites were approached.

RESULTS

Seventy-one (62%) sites responded. Baseline neonatal intensive care unit characteristics and HIE volume were comparable between groups. Most centers monitor invasive blood pressure; however, we identified 17 unique definitions of hypotension. TnECHO centers were likelier to trend systolic/diastolic blood pressure and request earlier echocardiography. TnECHO responders were less likely to use fluid boluses; TnECHO responders more commonly chose an inotrope first-line, while non-TnECHO centers used a vasopressor. For HRF, TnECHO centers chose vasopressors with a favorable pulmonary vascular profile. Non-TnECHO centers used more dopamine and more extracorporeal membrane oxygen for patients with HRF.

CONCLUSIONS

Cardiovascular practices in neonates with HIE differ between centers with and without TnECHO. Consensus regarding the definition of hypotension is lacking and dopamine use is common. The merits of these practices among these patients, who frequently have comorbid pulmonary hypertension and RV dysfunction, need prospective evaluation.

IMPACT

Cardiovascular care following HIE while undergoing therapeutic hypothermia varies between centers with access to trained hemodynamics specialists and those without. Because cardiovascular dysfunction is associated with brain injury, precision medicine-based care may be an avenue to improving outcomes. Therapeutic hypothermia has introduced new physiological considerations and enhanced survival. It is essential that hemodynamic strategies evolve to keep pace; however, little literature exists. Lack of consensus regarding fundamental definitions (e.g., hypotension) highlights the importance of collaboration among the scientific community to advance the field. The value of enhanced cardiovascular care guided by hemodynamic specialists requires prospective evaluation.

Cerebral blood flow velocity and oxygenation correlate predominantly with right ventricular function in cooled neonates with moderate-severe hypoxic-ischemic encephalopathy

The relationship between right ventricular (RV) function and cerebral blood flow (CBF) velocity and cerebral oxygenation was assessed in neonates with hypoxic-ischemic encephalopathy (HIE) treated with therapeutic hypothermia (TH). Echocardiographic, transcranial Doppler, and hemodynamic data from 37 neonates with moderate-severe HIE + TH were reviewed. Twenty healthy newborns served as controls. Cardiac dysfunction in HIE + TH was characterized by a predominant RV dysfunction, with concomitantly reduced CBF velocity. A significant correlation was found between CBF velocity and tricuspid annular plane systolic excursion (TAPSE), RV output (RVO), and stroke volume (SV_RV), as well as with left ventricular output and stroke volume. Brain oxygenation (rSO2) correlated significantly with RVO, SV_RV, TAPSE, ejection fraction, and fractional shortening, whereas cerebral fractional tissue oxygen extraction (FTOEc) correlated with RVO, SV_RV, RV myocardial performance index, and superior vena cava flow. CBF velocity and cerebral NIRS correlations were stronger with parameters of right ventricular performance.Conclusion: CBF velocity and brain oxygenation correlate predominantly with RV function in HIE + TH. This suggests a preferential contribution of RV performance to cerebral hemodynamics in this context. What is Known: • Neonates with hypoxic ischemic encephalopathy frequently exhibit alterations of cardiac function and cerebral blood flow. • These are considered organ-specific consequences of perinatal asphyxia. What is New: • We show that cerebral blood flow velocity and brain oxygenation are correlated predominantly with right ventricular function during therapeutic hypothermia. • This suggests a potential direct contribution of right ventricular performance to cerebral hemodynamics in this context.

Optimizing hemodynamic care in neonatal encephalopathy

Hemodynamic impairment occurs in up to 80% of infants with neonatal encephalopathy (NE). Not all infants benefit from therapeutic hypothermia (HT); there are some indications that the trajectory of brain injury might be modified by neurologic monitoring and early management over the first 72-h period. It is also possible that optimizing hemodynamic management may further improve outomes. The coupling between cerebral blood flow and cerebral metabolism is disrupted in NE, increasing the vulnerability of the newborn brain to secondary injury. Hemodynamic monitoring is usually limited to blood pressure and functional echocardiographic measurements, which may not accurately reflect brain perfusion. This review explores the evidence base for hemodynamic assessment and management of infants with NE while undergoing HT. We discuss the literature behind a systematic approach to a baby with NE with the aim to define best therapies to optimize brain perfusion and reduce secondary injury.

Management of Neonatal Hypotension and Shock

The current standard approach to manage circulatory insufficiency is inappropriately simple and clear: respond to low blood pressure to achieve higher values. However, the evidence for this is limited affecting all steps within the process: assessment, decision making, therapeutic options, and treatment effects. We have to overcome the 'one size fits all' approach and respect the dynamic physiologic transition from fetal to neonatal life in the context of complex underlying conditions. Caregivers need to individualize their approaches to individual circumstances. This paper will review various clinical scenarios, including managing transitional low blood pressure, to circulatory impairment involving different pathologies such as hypoxia-ischemia and sepsis. We will highlight the current evidence and set potential goals for future development in these areas. We hope to encourage caregivers to question the current standards and to support urgently needed research in this overlooked but crucial field of neonatal intensive care.

Updates on Management for Acute and Chronic Phenotypes of Neonatal Pulmonary Hypertension

Neonatal pulmonary hypertension is a heterogeneous disease in term and preterm neonates. It is characterized by persistent increase of pulmonary artery pressures after birth (acute) or an increase in pulmonary artery pressures after approximately 4 weeks of age (chronic); both phenotypes result in exposure of the right ventricle to sustained high afterload. In-depth clinical assessment plus echocardiographic measures evaluating pulmonary blood flow, pulmonary vascular resistance, pulmonary capillary wedge pressure, and myocardial contractility are needed to determine the cause and provide individualized targeted therapies. This article summarizes the causes, risk factors, hemodynamic assessment, and management of neonatal pulmonary hypertension.

Hypothermia and Cardiovascular Instability

Severely asphyxiated neonates have acute heart failure as part of their multiorgan dysfunction syndrome during the first days of life. Supporting the cardiovascular system during this phase is part of contemporary treatment and regarded as vital for limiting the neurodevelopmental injury. The decision to treat cardiovascular instability should be based on evaluation of end-organ function. Neonatologist-performed echocardiography in combination with other diagnostic modalities enables comprehensive real-time assessment. This review discusses associations between hemodynamics and adverse outcome, modalities for evaluating the hemodynamic state of the infant, and therapeutic approaches during intensive care.