Hemodynamic assessment by neonatologist using echocardiography: Primary provider versus consultation model.

Hemodynamic instability is very common in sick neonates and the currently used traditional hemodynamic monitoring tools lack sensitivity and specificity. Hemodynamic evaluation on echocardiography can provide direct information regarding the pathophysiology causing the hemodynamic instability and help the bedside clinician in making a personalized treatment approach based upon the deranged pathophysiology. Assessment of cardiac function and hemodynamics is essential in the management of neonates with cardiorespiratory failure, and hence neonatologist-performed echocardiography is becoming an essential tool in modern neonatal care. Depending on the level and size of the NICU, there is a daily need for echocardiography, and for a subset of sick infants, serial echocardiographic assessments are warranted. Comprehensive guidelines for neonatologists performing echocardiography and targeted neonatal echocardiography have been published providing a framework for training and quality assurance. There has been a significant interest among the providers to learn echocardiography skills. This manuscript explores the various needs of neonatal care providers around echocardiography, the current challenges neonatologists face in learning echocardiography, and how they, especially neonatal fellows, can learn these important skills during their training.

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.

Current Trends in Invasive Closure of Patent Ductus Arteriosus in Very Low Birth Weight Infants in United States Children's Hospitals, 2016-2021.

OBJECTIVE: To describe the current practices in invasive patent ductus arteriosus (PDA) closure (surgical ligation or transcatheter occlusion) in very low birth weight (VLBW) infants and changes in patient characteristics and outcomes from 2016 to 2021 among US children's hospitals. STUDY DESIGN: We evaluated a retrospective cohort of VLBW infants (birth weight 400-1499 g and gestational age 22-31 weeks) who had invasive PDA closure within 6 months of age from 2016 to 2021 in children's hospitals in the Pediatric Health Information System. Changes in patient characteristics and outcomes over time were evaluated using generalized linear models and generalized linear mixed models. RESULTS: 2418 VLBW infants (1182 surgical ligation; 1236 transcatheter occlusion) from 42 hospitals were included. The proportion of infants receiving transcatheter occlusion increased from 17.2% in 2016 to 84.4% in 2021 (P < .001). In 2021, 28/42 (67%) hospitals had performed transcatheter occlusion in > 80% of their VLBW infants needing invasive PDA closure, compared with only 2/42 (5%) in 2016. Although median postmenstrual age (PMA) at PDA closure did not change for the overall cohort, PMA at transcatheter occlusion decreased from 38 weeks in 2016 to 31 weeks by 2020, P < .001. Among those infants not intubated prior to PDA closure, extubation within 3 days postprocedure increased over time (yearly adjusted odds ratios of 1.26 [1.08-1.48]). Length of stay and mortality did not change over time. CONCLUSION: We report rapid adoption of transcatheter occlusion for PDA among VLBW infants in US children's hospitals over time. Transcatheter occlusions were performed at younger PMA over time.

Effect of assessing velocity time integral at different locations across ventricular outflow tracts when calculating cardiac output in neonates.

This study aims to evaluate the effect of assessing velocity time integral at different locations across ventricular outflow tracts for calculating cardiac output (CO) in neonates. Velocity time integral (VTI) and CO were measured at 3 different locations across right and left ventricular outflow tracts using transthoracic echocardiography in healthy term neonates without any major congenital heart disease. ANOVA with Bonferroni correction was used to determine the differences between the VTI and CO sampled at these three locations. Forty-one neonates met inclusion criteria with mean gestational age of 38.6 ± 1 weeks and mean birth weight of 3155 ± 463 g. The median hours after birth when echocardiography was obtained was 23 h (range 11-68 h after birth). Left CO were 121 ± 30 mL/kg/min, 155 ± 38 mL/kg/min, and 176 ± 36 mL/kg/min measured below the valve, hinges of the valve, and tip of the valve, respectively. Right CO were 197 ± 73 mL/kg/min, 270 ± 83 mL/kg/min, and 329 ± 104 mL/kg/min measured below the valve, hinges of the valve, and tip of the valve, respectively. A statistically significant difference (P < 0.001) was found in the VTI and CO measured at the 3 different locations across both left and right ventricular outflow tracts.     Conclusions: There is a significant difference in measurements of VTI and CO depending on the location of Doppler gate sampling across the ventricular outflow tracts. Consistency and precision in Doppler gate location are essential for measuring VTI and calculating CO while assessing changes in hemodynamic status in critically ill infants. What is Known: • Targeted Neonatal Echocardiography is increasingly applied to measure cardiac output in critically ill neonates and serial assessments are performed to assess the trend in changes in cardiac output. • Noninvasive measurement using velocity time integral to calculate cardiac output is commonly performed. However, location of Doppler sample gate to measure ventricular outflow tract velocity time integral is not consistent. What is New: • Statistically significant changes in measured velocity time integral and cardiac output are noted based on the location of Doppler gate sampling. • To monitor the cardiac output for trending, it is important to be consistent with regards to the location of the Doppler sample gate to assess changes in cardiac output in critically ill newborns.

Effectiveness of Simulation Training in Acquiring Echocardiography Skills among Neonatology Care Providers.

OBJECTIVE: The objective of this study was to test the hypothesis that simulation training improves echocardiography skills. STUDY DESIGN: In this prospective study, 43 participants (16 neonatologists, 26 neonatology fellows, and 1 nurse practitioner) were tested on the simulator after 4 hours of didactic sessions on topographical cardiac anatomy and standard echocardiographic views. Participants were given 20 minutes to obtain and save the standard views. After the simulation hands-on training for 8 hours over 3 days, they were tested again. Each image was scored from 0 to 3 based on the image quality. Pre- and postsimulator training data were compared using both automated and visual scoring methods. RESULTS: After the hands-on simulator training, the automated median (interquartile) score for the quality of acquired images increased from 36 (22, 43) to 55 (48, 58), p < 0.0001. The increase was similar using visual scoring. The number of views with acceptable or good image quality (scores of 2 or 3) increased from 11 (6, 16) to 20 (17, 21), p < 0.0001. The neonatology fellows and faculty, as well as those with or without prior echocardiography experience, demonstrated significant improvement. CONCLUSIONS: Echocardiography simulation is an effective tool in improving echocardiography skills among neonatology care providers. KEY POINTS: · Simulation is effective in acquiring echocardiography skills among neonatology care providers.. · Simulation improves image acquisition in those with and without prior echocardiography experience.. · Effectiveness of simulation in retaining the acquired echocardiography skill should be investigated..

Recognition and management of neonatal hemodynamic compromise.

Hemodynamic compromise of the neonate can occur in various clinical situations, including but not limited to maladaptation during the early transitional period, sepsis, congenital heart anomalies, hemodynamically significant patent ductus arteriosus, persistent pulmonary hypertension of the newborn, systemic inflammatory diseases such as necrotizing enterocolitis, and dehydration. Despite the handful of advances in neonatal care through ground-breaking clinical trials, the management of neonatal shock is often dependent on the bedside clinician's experience and training without the aid of high-level evidence. However, the recognition for the importance of comprehensive and serial hemodynamic assessment is growing. There is now a wealth of literature investigating the use of functional echocardiography, near-infrared spectroscopy, and noninvasive impedance-based cardiometry to complement common bedside hemodynamic measures such as blood pressure and heart rate measurement. In this review article, the pathophysiology of neonatal hemodynamic compromise is outlined, and concomitant best-evidence management for hemodynamic compromise in the neonate is proposed.

Development and validation of an automated assessment tool of echocardiography skills acquired on a neonatal simulator.

INTRODUCTION: Simulators are increasingly used for training in echocardiography. However, there is no objective method to assess the skills acquired. Our objective was to develop and test an automated method to assess echocardiography skills. METHODS: To automate the image quality evaluation, we expanded our previously developed neonatal echocardiography simulator to enable recording of images of the 26 standard cuts and process the image quality. We then compared the automated and visual methods in scoring image quality of the echocardiograms obtained by 22 trainees. RESULTS: Each echocardiographic image representing a slice of a three-dimensional volume possesses 3 axes (X, Y, and Z) that correspond to the roll, pitch, and yaw angles of the transducer, respectively. Therefore, if the placement and orientation of the transducer are correct, the acquired image represents the appropriate cardiac window with the desired orientation in all 3 axes. The automated system gives a score of 0 if the transducer is not in the appropriate cardiac window. A score of 1, 2, or 3 is given if the image falls within the range of one, two, or three angles, respectively. There was no difference in the image quality score between automated and visual assessment methods (46.0 ± 13.0 vs 45.1 ± 14.4, P = .19). The two methods had excellent correlation (r = .95). The bias and precision were 0.9 and 8.8, respectively. CONCLUSIONS: The automated method is comparable to visual method for assessment of image quality. The automated process allows for instantaneous feedback and has the potential to standardize assessment of echocardiography skills of trainees.

Corticosteroids for Neonatal Hypotension.

Several limitations and controversies surround the definition of hypotension; however, it remains one of the most common problems faced by neonates. Approximately 15% to 30% of neonates with hypotension fail to respond to volume and/or vasopressor or inotropes. They are considered to have refractory hypotension. Although it is thought to have multiple causes, absolute and relative adrenal insufficiency is considered as the main reason for refractory hypotension. This article focuses on the role of adrenal insufficiency in causing refractory hypotension in preterm and term infants, the different options of corticosteroids available, and their risk/benefit profiles.

Effects of Patent Ductus Arteriosus on Organ Blood Flow in Infants Born Very Preterm: A Prospective Study with Serial Echocardiography.

OBJECTIVE: To characterize the effects of a patent ductus arteriosus (PDA) on different organ blood flows in infants born preterm. STUDY DESIGN: Infants born preterm at ≤30 weeks of gestational age had daily echocardiography and Doppler assessments of middle cerebral artery, celiac artery, superior mesenteric (SMA), and renal arteries (RA) during the first postnatal week. Abnormal organ blood flow was defined as either reverse or absent diastolic flow, abnormally low mean or systolic velocities, or abnormally high pulsatility or resistance index. RESULTS: Twenty-five infants born very preterm (gestational age 27.0 ± 2.1 weeks) were enrolled. PDA presence at time of measurement increased the risk of abnormal organ blood flows (39% vs 8%, P < .001). Ductal diameter and left atrium-to-aortic root (LA/Ao) ratio correlated positively with resistance index (celiac artery, SMA, RA), and negatively with mean velocity (ductal diameter: SMA, RA; LA/Ao ratio: RA). A PDA >2.0 mm, LA/Ao ratio >1.4, and their combination were associated with 8.0 (95% CI 1.6-39.4)-, 6.7 (1.3-34.7)-, and 38.2 (3.2-455.5)-fold increase in risk of abnormal organ blood flow index, respectively. Abnormal descending aorta flow was detected in only 2% of measurements. CONCLUSIONS: Ductal size >2.0 mm and LA/Ao >1.4, especially in combination, are associated with a greater risk of abnormal organ blood flows. We suggest that Doppler assessment of the renal and superior mesenteric arteries are more likely to detect systemic hypoperfusion than the descending aorta.

Inhaled nitric oxide as an adjunct to neonatal resuscitation in premature infants: a pilot, double blind, randomized controlled trial.

BACKGROUND: Nitric oxide (NO) plays an important role in normal postnatal transition. Our aims were to determine whether adding inhaled NO (iNO) decreases supplemental oxygen exposure in preterm infants requiring positive pressure ventilation (PPV) during resuscitation and to study iNO effects on heart rate (HR), oxygen saturation (SpO2), and need for intubation during the first 20 min of life. METHODS: This was a pilot, double-blind, randomized, placebo-controlled trial. Infants 25 0/7-31 6/7 weeks' gestational age requiring PPV with supplemental oxygen during resuscitation were enrolled. PPV was initiated with either oxygen (FiO2-0.30) + iNO at 20 ppm (iNO group) or oxygen (FiO2-0.30) + nitrogen (placebo group). Oxygen was titrated targeting defined SpO2 per current guidelines. After 10 min, iNO/nitrogen was weaned stepwise per protocol and terminated at 17 min. RESULTS: Twenty-eight infants were studied (14 per group). The mean gestational age in both groups was similar. Cumulative FiO2 and rate of exposure to high FiO2 (>0.60) were significantly lower in the iNO group. There were no differences in HR, SpO2, and need for intubation. CONCLUSIONS: Administration of iNO as an adjunct during neonatal resuscitation is feasible without side effects. It diminishes exposure to high levels of supplemental oxygen.

Hemodynamic management in chronically ventilated infants.

Positive pressure ventilation can significantly alter hemodynamics. The reduction in systemic venous return and increase in right ventricular afterload in response to an inappropriately high mean airway pressure can decrease pulmonary blood flow and compromise systemic perfusion as a result. In addition to ventilator parameters, the degree of hemodynamic effects depends on the baseline cardiac function and lung compliance. Furthermore, the chronically ventilated infants often have a multitude of comorbidities which may also impact hemodynamics. These include pulmonary and systemic hypertension which can lead to myocardial dysfunction as a result of the increase in the right and left ventricular afterload, respectively. In this section, we aim to outline the hemodynamic changes associated with chronic lung disease and mechanical ventilation and discuss management options.

Delivery room emergencies in critical congenital heart diseases.

Transition from fetal to postnatal life is a complex process. Even in the absence of congenital heart disease, about 4-10% of newborns require some form of assistance in the delivery room. Neonates with complex congenital heart disease should be expected to require significant intervention and thus the resuscitation team must be well prepared for such a delivery. Prenatal assessment including fetal and maternal health in general and detailed information on fetal heart structure, function and hemodynamics in particular are crucial for planning the delivery and resuscitation. In addition, understanding the impact of cardiac structural anomaly and associated altered blood flow on early postnatal transition is essential for success of resuscitation in the delivery room. In this article, we will briefly review transitional circulation focusing on altered hemodynamics of the complex congenital heart diseases and then discuss the process of preparing for these high-risk deliveries. Finally, we will review the pathophysiology resulting from the cardiac structural anomaly with resultant altered fetal circulation and discuss delivery room management of specific critical congenital heart diseases.

What is a hemodynamically significant PDA in preterm infants?

OBJECTIVE: There is no consensus on the definition of a hemodynamically significant patent ductus arteriosus (hsPDA). In this review article, our objective is to discuss the main variables that one should consider when determining the hemodynamic significance of a PDA. RESULTS: We describe the various approaches that have been utilized over time to define an hsPDA and discuss the strengths and weaknesses of each echocardiographic index. Finally, we propose a comprehensive and individualized approach in determining the hemodynamic significance of the PDA. CONCLUSION: There are several PDA-related clinical, echocardiographic, and other objective variables to take into consideration when defining an hsPDA. However, vulnerability based on gestational or chronological age is an important contributor as well.

Predictors of Respiratory Improvement 1 Week after Ligation of Patent Ductus Arteriosus in Preterm Infants.

OBJECTIVE: To characterize preterm infants that demonstrates respiratory improvement 7 days after ligation of a patent ductus arteriosus (PDA). STUDY DESIGN: We performed a 2-phase study of preterm infants (birthweight <1500 g between 2010 and 2016). We first did a retrospective analysis using regression modeling of ligation population. We then performed a case-control study comparing a ligation group with infants matched by gestational age, postnatal age, and preligation respiratory condition (ventilator mode, mean airway pressure [MAP], and fraction of inspired oxygen [FiO2]). Respiratory improvement was defined as either extubation, downgrading of ventilatory mode, reduction in MAP >25%, or decrease in FiO2 >25%. RESULTS: Forty-five (42%) of 107 preterm infants (gestational age 25.5 ± 1.7 weeks) with ligation showed respiratory improvement at 7 days. Infants on high frequency ventilation (HFV) were more likely to have respiratory improvement (aOR 5.03, 95% CI [1.14-22.18]). In matched-control analysis of 89 pairs, there was no difference in respiratory improvement. Among infants on HFV, the ligation group had an increase in MAP during 3 days prior to ligation. For infants on conventional ventilation, the ligation group had higher MAP and FiO2 than the control group during the first 2-3 postoperative days. CONCLUSIONS: Among infants undergoing PDA ligation, those on HFV were more likely to have respiratory improvement in the first week, possibly because of the prevention of further respiratory deterioration. For infants on conventional ventilation, ligation was associated with higher respiratory support in the immediate postligation period without respiratory benefits at 7 days. As HFV was used as a rescue mode, our findings suggest that those with worse lung disease may achieve greater short term benefit from PDA ligation.

Virtual Neonatal Echocardiographic Training System (VNETS): An Echocardiographic Simulator for Training Basic Transthoracic Echocardiography Skills in Neonates and Infants.

There is a great need for training in pediatric echocardiography. In addition to physicians being trained in pediatric cardiology and echocardiography technologists, neonatologist, pediatric intensivists, and other health care professionals may be interested in such training. Since, there is limited opportunity of training on live patients, echocardiographic simulators may be of help. No simulator with complete range of echocardiographic modalities is available for neonates and infants. The aim of this project was to develop a mannequin-based echocardiographic simulator capable of simulating full range of pediatric 2D, color flow Doppler, spectral Doppler, and M-mode echocardiograms. A mannequin, a laptop computer, a magnetic tracking device, and a six-degree freedom (6DOF) sensor incorporated in a dummy transducer serve as the hardware platform of the simulator. We obtained six to seven 4D echocardiographic datasets in DICOM format through five acoustic windows from each infant along with a complete set of 2D video clips of color flow, Doppler, and M-mode. The 4D datasets are sliced into 3D slices using the visualization toolkit and are displayed as 2D echocardiograms through the information obtained by the 6DOF sensor. The coordinates from specific 3D slices triggers display of video clips of color flow, M-mode, and Doppler echocardiogram. Software written in C++ programming language controls the basic function of the program. The main simulator screen displays the full range of 2D echocardiograms including color flow Doppler, spectral Doppler, and M-mode from each acoustic window, whereas the side screen display the position and motion of the cutting planes through a 3D heart model. The system includes a software module to perform hemodynamic measurements from specific video clips images. Our hybrid, mannequin-based pediatric echocardiography simulator provides full range of pediatric echocardiography training experience. This simulator may help training in pediatric echocardiography for which there is a growing demand in clinical medicine.

Initial hematocrit values after birth and peri/intraventricular hemorrhage in extremely low birth weight infants.

OBJECTIVE: Ischemia followed by reperfusion plays a significant role in the pathogenesis of peri/intraventricular hemorrhage (P/IVH). Delayed cord clamping promotes placental transfusion to newborn and is associated with decreased P/IVH. We hypothesized that extremely low birth weight (ELBW) infants with higher initial hematocrit (Hct) after birth are less likely to develop P/IVH. STUDY DESIGN: Pre- and postnatal data on inborn ELBW infants over 7 years were reviewed. We examined the relationship between P/IVH in the first week and initial Hct using logistic regression modeling. RESULTS: We studied 225 infants with a median gestational age (GA) 25.7 (22.4-31.7). Forty-one percent had grade I-IV P/IVH. In univariate analysis, cesarean section (CS) and higher GA, birth weight, 5-minute Apgar, and initial Hct were associated with decreased likelihood of P/IVH while higher maximum PCO2 in first 3 days and use of inotropes/vasopressors, postnatal steroid for hypotension, hypernatremia, transfusion, and use of insulin for hyperglycemia during the first week of life were associated with increased likelihood of P/IVH. In multiple regression analysis, only GA, CS, and initial Hct remained significantly associated with P/IVH. Adjusting for GA and CS, the odds of P/IVH was higher with Hct < 40% (OR 2.04, 95% CI [1.11, 3.76]) and Hct < 45% (2.38 [1.19, 4.76]). CONCLUSION: Higher initial Hct is associated with decreased P/IVH. Initial Hct < 45% was associated with a 2-fold increase in P/IVH. We speculate that lower initial Hct represents a lower intravascular volume status and promotes cerebral hypoperfusion preceding P/IVH.

Variable role of patent ductus arteriosus.

Although patent ductus arteriosus is essential in fetal life, interventions to close or minimize the adverse hemodynamic effects associated with the left-to-right shunt are often needed after birth, especially in extremely premature infants. However, there are clinical conditions where maintaining patency of the ductus is essential for survival. In this article we discuss use of prostaglandin E1 in the management of congenital heart defects, pulmonary hypertension and left ventricular failure in early neonatal period.

Hemodynamic Changes During Rewarming Phase of Whole-Body Hypothermia Therapy in Neonates with Hypoxic-Ischemic Encephalopathy.

OBJECTIVE: To delineate the systemic and cerebral hemodynamic response to incremental increases in core temperature during the rewarming phase of therapeutic hypothermia in neonatal hypoxic-ischemic encephalopathy (HIE). STUDY DESIGN: Continuous hemodynamic data, including heart rate (HR), mean arterial blood pressure (MBP), cardiac output by electrical velocimetry (COEV), arterial oxygen saturation, and renal (RrSO2) and cerebral (CrSO2) regional tissue oxygen saturation, were collected from 4 hours before the start of rewarming to 1 hour after the completion of rewarming. Serial echocardiography and transcranial Doppler were performed at 3 hours and 1 hour before the start of rewarming (T-3 and T-1; "baseline") and at 2, 4, and 7 hours after the start of rewarming (T+2, T+4, and T+7; "rewarming") to determine Cardiac output by echocardiography (COecho), stroke volume, fractional shortening, and middle cerebral artery (MCA) flow velocity indices. Repeated-measures analysis of variance was used for statistical analysis. RESULTS: Twenty infants with HIE were enrolled (mean gestational age, 38.8 ± 2 weeks; mean birth weight, 3346 ± 695 g). During rewarming, HR, COecho, and COEV increased from baseline to T+7, and MBP decreased. Despite an increase in fractional shortening, stroke volume remained unchanged. RrSO2 increased, and renal fractional oxygen extraction (FOE) decreased. MCA peak systolic flow velocity increased. There were no changes in CrSO2 or cerebral FOE. CONCLUSIONS: In neonates with HIE, CO significantly increases throughout rewarming. This is due to an increase in HR rather than stroke volume and is associated with an increase in renal blood flow. The lack of change in cerebral tissue oxygen saturation and extraction, in conjunction with an increase in MCA peak systolic velocity, suggests that cerebral flow metabolism coupling remained intact during rewarming.