Perinatal Caffeine Administration Improves Outcomes in an Ovine Model of Neonatal Hypoxia-Ischemia.

BACKGROUND: Neonatal hypoxic-ischemic encephalopathy disproportionately affects low- and middle-income countries, where ≈96% of affected infants reside. The current standard of care, therapeutic hypothermia, is frequently ineffective in this setting, likely because injury may be occurring earlier during labor. Here, we studied the pharmacokinetics, safety, and efficacy of perinatal caffeine administration in near-term lambs following global ischemic injury to support the development of earlier treatment strategies targeting the fetus in utero as well as the infant postnatally. METHODS: Ewes were randomly assigned to receive either 1 g IV caffeine citrate or placebo before delivery and placental transport assessed. Near-term lambs (141-143 days) of both sexes were subjected to severe global hypoxia-ischemia utilizing an acute umbilical cord occlusion model. Lambs that received caffeine in utero also received 20 mg/kg IV caffeine citrate following resuscitation and 10 mg/(kg·d) IV for 2 days. An additional cohort received 60 mg/kg followed by 30 mg/(kg·d) (low dose versus high dose) postnatally. Biochemical, histological, and neurological outcome measures in lambs were assessed over a 6-day period. RESULTS: Perinatal caffeine administration demonstrated excellent placental transport kinetics and was well tolerated with lamb plasma levels comparable to those targeted in neonates with apnea of prematurity. Caffeine administration resulted in a systemic immunomodulatory effect, evidenced by significant reductions in proinflammatory IP-10 levels. Treated lambs demonstrated improved neurodevelopmental outcomes, while histological analysis revealed that caffeine reduced gray matter injury and attenuated inflammation in the cingulate and parasagittal cortex. This neuroprotective effect was greater and via a different mode of action than we previously reported for azithromycin. A higher caffeine dosing regimen demonstrated significant toxicity. CONCLUSIONS: Perinatal caffeine administration is well tolerated, attenuates systemic and brain inflammation, and contributes to improvements in histological and neurological outcomes in an ovine model of neonatal hypoxic-ischemic encephalopathy.

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.

Neonatal resuscitation with continuous chest compressions and high frequency percussive ventilation in preterm lambs.

BACKGROUND: Cerebral oxygen delivery (cDO2) is low during chest compressions (CC). We hypothesized that gas exchange and cDO2 are better with continuous CC with high frequency percussive ventilation (CCC + HFPV) compared to conventional 3:1 compressions-to-ventilation (C:V) resuscitation during neonatal resuscitation in preterm lambs with cardiac arrest induced by umbilical cord compression. METHODS: Fourteen lambs in cardiac arrest were randomized to 3:1 C:V resuscitation (90CC + 30 breaths/min) per the Neonatal Resuscitation Program guidelines or CCC + HFPV (120CC + HFPV continuously). Intravenous epinephrine was given every 3 min until return of spontaneous circulation (ROSC). RESULTS: There was no difference in the incidence and time to ROSC between both groups. Median (IQR) PaCO2 was significantly lower with CCC + HFPV during CC, at ROSC and 15 min post-ROSC-[104 (99-112), 83 (77-99), and 43 (40-64)], respectively compared to 3:1 C:V-[149 (139-167), 153 (143-168), and 153 (138-178) mmHg. PaO2 and cDO2 were higher with CCC + HFPV during CC and at ROSC. PaO2 was similar 15 min post-ROSC with a lower FiO2 in the CCC + HFPV group 0.4 (0.4-0.5) vs. 1 (0.6-1). CONCLUSION: In preterm lambs with perinatal cardiac-arrest, continuous chest compressions with HFPV does not improve ROSC but enhances gas exchange and increases cerebral oxygen delivery compared to 3:1 C:V during neonatal resuscitation. IMPACT STATEMENT: Ventilation is the most important intervention in newborn resuscitation. Currently recommended 3:1 compression-to-ventilation ratio is associated with hypercarbia and poor oxygen delivery to the brain. Providing uninterrupted continuous chest compressions during high frequency percussive ventilation is feasible in a lamb model of perinatal cardiac arrest, and demonstrates improved gas exchange and oxygen delivery to the brain. This is the first study in premature lambs evaluating high frequency percussive ventilation with asynchronous chest compressions and lays the groundwork for future clinical studies to optimize gas exchange and hemodynamics during chest compressions in newborns.

Caffeine pharmacokinetics following umbilical vein injection during delayed cord clamping in preterm lambs.

BACKGROUND: Spontaneous breathing during and after delayed cord clamping (DCC) stabilizes cardiopulmonary transition at birth. Caffeine stimulates breathing and decreases apnea in premature newborns. We evaluated the pharmacokinetics and physiological effects of early caffeine administration-direct injection into the umbilical vein (UV) during DCC or administered through a UV catheter (UVC) after delivery. METHODS: Eighteen extremely premature lambs (125-127d, term gestation 145d) were exteriorized and instrumented. Lambs received caffeine-citrate at high (40 mg/kg) or standard-dose (20 mg/kg) via direct UV (DUV) injection during DCC, or via the UVC. RESULTS: Mean peak plasma caffeine concentrations were lower with high-dose DUV compared to UVC (18 ± 4.3 vs. 46 ± 12 mg/L, p < 0.05). With standard-dose caffeine, mean peak plasma levels were 7.48 ± 2.6 with DUV and 28.73 ± 9.4 mg/L with UVC. The volume of distribution was higher in the DUV group compared to UVC (2.5 ± 1.0 vs. 0.69 ± 0.15 L/kg) with an estimated 39 ± 18% entering the maternal circulation. Maternal peak concentrations were 0.79 ± 0.71 and 1.43 ± 0.74 mg/L with standard and high-dose DUV, respectively. CONCLUSIONS: Caffeine injected directly into the UV during DCC is feasible but achieves lower concentrations due to high volume of distribution including maternal circulation. Further trials evaluating DUV caffeine injection should use higher caffeine doses. IMPACT: Respiratory stimulation with early caffeine may reduce the need for intubation in preterm infants. In the preterm lambs, caffeine injection directly into the umbilical vein during delayed cord clamping is feasible. Plasma caffeine concentrations are less than half when administered directly into the umbilical vein during delayed cord clamping compared to administration via an umbilical venous catheter following birth likely attributed to a larger volume of distribution or injection site leak. There were no significant hemodynamic alterations following caffeine injection.

Pediatric subspecialty workforce: what is needed to secure its vitality and survival?

IMPACT: The pediatric subspecialty workforce is challenged by shortages and geographic maldistribution of subspecialists. We invited leaders in pediatrics to discuss how the field's vitality and survival can be secured. These leaders presented their own opinions and not the opinion of the society or organization that they are presenting. Early exposure of future trainees to pediatrics and advocacy for improved reimbursement structures, loan repayment, and funded programs for physician scientists will enhance the recruitment and retention of pediatric subspecialists to guarantee advancement of knowledge and the appropriate care of children with chronic and complex diseases.

Oral sildenafil versus bosentan for treatment of persistent pulmonary hypertension of the newborn: a randomized controlled trial.

BACKGROUND: Access to inhaled nitric oxide (iNO) is limited in low resource settings due to non-availability and high cost. There is a need for research on low-cost alternative therapies for management of persistent pulmonary hypertension of the newborn (PPHN). We aimed to compare oral sildenafil and bosentan as monotherapy in the treatment of neonates with PPHN. STUDY DESIGN: In this single-centre open-label randomized controlled trial (RCT), term and late preterm neonates with PPHN, defined as pulmonary arterial systolic pressure (PASP) > 35 mmHg and requiring fraction of inspired oxygen (FiO2) > 0.21, were randomized to receive oral sildenafil and bosentan. The primary outcome was reduction of PASP by 25% within 48 h after start of drug. RESULTS: Thirty-six neonates were analyzed (18 in each group). Initial PASPs were similar in both groups. The median (IQR) time for the primary outcome (PASP to reduce by 25% within 48 h) was 36 (24-48) h and 96 (48-120) h in sildenafil and bosentan groups respectively (p = 0.008). There was also a higher need to add other pulmonary vasodilators in bosentan group as compared to sildenafil group (p = 0.006). CONCLUSION: Sildenafil was associated with quicker reduction of PASP and FiO2 in neonates with PPHN, as compared to bosentan. Large multicentre blinded trials to assess efficacy and safety of bosentan in comparison with other pulmonary vasodilators would help to get a clearer understanding of its role in the management of PPHN, particularly for use in resource-limited settings that lack iNO. CLINICAL TRIAL REGISTRATION: https://ctri.nic.in/Clinicaltrials/rmaindet.php? trialid=63997&EncHid=39716.16132&modid=1&compid=19[CTRI/2022/06/043328].

Perinatal Azithromycin Provides Limited Neuroprotection in an Ovine Model of Neonatal Hypoxic-Ischemic Encephalopathy.

BACKGROUND: Hypoxic-ischemic brain injury/encephalopathy affects about 1.15 million neonates per year, 96% of whom are born in low- and middle-income countries. Therapeutic hypothermia is not effective in this setting, possibly because injury occurs significantly before birth. Here, we studied the pharmacokinetics, safety, and efficacy of perinatal azithromycin administration in near-term lambs following global ischemic injury to support earlier treatment approaches. METHODS: Ewes and their lambs of both sexes (n=34, 141-143 days) were randomly assigned to receive azithromycin or placebo before delivery as well as postnatally. Lambs were subjected to severe global hypoxia-ischemia utilizing an acute umbilical cord occlusion model. Outcomes were assessed over a 6-day period. RESULTS: While maternal azithromycin exhibited relatively low placental transfer, azithromycin-treated lambs recovered spontaneous circulation faster following the initiation of cardiopulmonary resuscitation and were extubated sooner. Additionally, peri- and postnatal azithromycin administration was well tolerated, demonstrating a 77-hour plasma elimination half-life, as well as significant accumulation in the brain and other tissues. Azithromycin administration resulted in a systemic immunomodulatory effect, demonstrated by reductions in proinflammatory IL-6 (interleukin-6) levels. Treated lambs exhibited a trend toward improved neurodevelopmental outcomes while histological analysis revealed that azithromycin supported white matter preservation and attenuated inflammation in the cingulate and parasagittal cortex. CONCLUSIONS: Perinatal azithromycin administration enhances neonatal resuscitation, attenuates neuroinflammation, and supports limited improvement of select histological outcomes in an ovine model of hypoxic-ischemic brain injury/encephalopathy.

Hemodynamic Changes with Umbilical Cord Milking in Nonvigorous Newborns: A Randomized Cluster Cross-over Trial.

OBJECTIVE: To assess the hemodynamic safety and efficacy of umbilical cord milking (UCM) compared with early cord clamping (ECC) in nonvigorous newborn infants enrolled in a large multicenter randomized cluster-crossover trial. STUDY DESIGN: Two hundred twenty-seven nonvigorous term or near-term infants who were enrolled in the parent UCM vs ECC trial consented for this substudy. An echocardiogram was performed at 12 ± 6 hours of age by ultrasound technicians blinded to randomization. The primary outcome was left ventricular output (LVO). Prespecified secondary outcomes included measured superior vena cava (SVC) flow, right ventricular output (RVO), peak systolic strain, and peak systolic velocity by tissue Doppler examination of the RV lateral wall and the interventricular septum. RESULTS: Nonvigorous infants receiving UCM had increased hemodynamic echocardiographic parameters as measured by higher LVO (225 ± 64 vs 187 ± 52 mL/kg/min; P < .001), RVO (284 ± 88 vs 222 ± 96 mL/kg/min; P < .001), and SVC flow (100 ± 36 vs 86 ± 40 mL/kg/min; P < .001) compared with the ECC group. Peak systolic strain was lower (-17 ± 3 vs -22 ± 3%; P < .001), but there was no difference in peak tissue Doppler flow (0.06 m/s [IQR, 0.05-0.07 m/s] vs 0.06 m/s [IQR, 0.05-0.08 m/s]). CONCLUSIONS: UCM increased cardiac output (as measured by LVO) compared with ECC in nonvigorous newborns. Overall increases in measures of cerebral and pulmonary blood flow (as measured by SVC and RVO flow, respectively) may explain improved outcomes associated with UCM (less cardiorespiratory support at birth and fewer cases of moderate-to-severe hypoxic ischemic encephalopathy) among nonvigorous newborn infants.

Umbilical cord milking in nonvigorous infants: a cluster-randomized crossover trial.

BACKGROUND: Delayed cord clamping and umbilical cord milking provide placental transfusion to vigorous newborns. Delayed cord clamping in nonvigorous newborns may not be provided owing to a perceived need for immediate resuscitation. Umbilical cord milking is an alternative, as it can be performed more quickly than delayed cord clamping and may confer similar benefits. OBJECTIVE: We hypothesized that umbilical cord milking would reduce admission to the neonatal intensive care unit compared with early cord clamping in nonvigorous newborns born between 35 and 42 weeks' gestation. STUDY DESIGN: This was a pragmatic cluster-randomized crossover trial of infants born at 35 to 42 weeks' gestation in 10 medical centers in 3 countries between January 2019 and May 2021. The centers were randomized to umbilical cord milking or early cord clamping for approximately 1 year and then crossed over for an additional year or until the required number of consented subjects was reached. Waiver of consent as obtained in all centers to implement the intervention. Infants were eligible if nonvigorous at birth (poor tone, pale color, or lack of breathing in the first 15 seconds after birth) and were assigned to umbilical cord milking or early cord clamping according to their birth hospital randomization assignment. The baseline characteristics and outcomes were collected following deferred informed consent. The primary outcome was admission to the neonatal intensive care unit for predefined criteria. The main safety outcome was hypoxic-ischemic encephalopathy. Data were analyzed by the intention-to-treat concept. RESULTS: Among 16,234 screened newborns, 1780 were eligible (905 umbilical cord milking, 875 early cord clamping), and 1730 had primary outcome data for analysis (97% of eligible; 872 umbilical cord milking, 858 early cord clamping) either via informed consent (606 umbilical cord milking, 601 early cord clamping) or waiver of informed consent (266 umbilical cord milking, 257 early cord clamping). The difference in the frequency of neonatal intensive care unit admission using predefined criteria between the umbilical cord milking (23%) and early cord clamping (28%) groups did not reach statistical significance (modeled odds ratio, 0.69; 95% confidence interval, 0.41-1.14). Umbilical cord milking was associated with predefined secondary outcomes, including higher hemoglobin (modeled mean difference between umbilical cord milking and early cord clamping groups 0.68 g/dL, 95% confidence interval, 0.31-1.05), lower odds of abnormal 1-minute Apgar scores (Apgar ≤3, 30% vs 34%, crude odds ratio, 0.72; 95% confidence interval, 0.56-0.92); cardiorespiratory support at delivery (61% vs 71%, modeled odds ratio, 0.57; 95% confidence interval, 0.33-0.99), and therapeutic hypothermia (3% vs 4%, crude odds ratio, 0.57; 95% confidence interval, 0.33-0.99). Moderate-to-severe hypoxic-ischemic encephalopathy was significantly less common with umbilical cord milking (1% vs 3%, crude odds ratio, 0.48; 95% confidence interval, 0.24-0.96). No significant differences were observed for normal saline bolus, phototherapy, abnormal 5-minute Apgar scores (Apgar ≤6, 15.7% vs 18.8%, crude odds ratio, 0.81; 95% confidence interval, 0.62-1.06), or a serious adverse event composite of death before discharge. CONCLUSION: Among nonvigorous infants born at 35 to 42 weeks' gestation, umbilical cord milking did not reduce neonatal intensive care unit admission for predefined criteria. However, infants in the umbilical cord milking arm had higher hemoglobin, received less delivery room cardiorespiratory support, had a lower incidence of moderate-to-severe hypoxic-ischemic encephalopathy, and received less therapeutic hypothermia. These data may provide the first randomized controlled trial evidence that umbilical cord milking in nonvigorous infants is feasible, safe and, superior to early cord clamping.

Multisystem inflammatory syndrome in children (MIS-C) and neonates (MIS-N) associated with COVID-19: optimizing definition and management.

During the SARS-CoV-2-associated infection (COVID-19), pandemic initial reports suggested relative sparing of children inversely related to their age. Children and neonates have a decreased incidence of SARS-CoV-2 infection, and if infected they manifested a less severe phenotype, in part due to enhanced innate immune response. However, a multisystem inflammatory syndrome in children (MIS-C) or paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 emerged involving coronary artery aneurysms, cardiac dysfunction, and multiorgan inflammatory manifestations. MIS-C has many similarities to Kawasaki disease and other inflammatory conditions and may fit within a spectrum of inflammatory conditions based on immunological results. More recently neonates born to mothers with SARS-CoV-2 infection during pregnancy demonstrated evidence of a multisystem inflammatory syndrome with raised inflammatory markers and multiorgan, especially cardiac dysfunction that has been described as multisystem inflammatory syndrome in neonates (MIS-N). However, there is a variation in definitions and management algorithms for MIS-C and MIS-N. Further understanding of baseline immunological responses to allow stratification of patient groups and accurate diagnosis will aid prognostication, and inform optimal immunomodulatory therapies. IMPACT: Multisystem inflammatory system in children and neonates (MIS-C and MIS-N) post COVID require an internationally recognized consensus definition and international datasets to improve management and plan future clinical trials. This review incorporates the latest review of pathophysiology, clinical information, and management of MIS-C and MIS-N. Further understanding of the pathophysiology of MIS-C and MIS-N will allow future targeted therapies to prevent and limit clinical sequelae.

Neonatal sepsis and cardiovascular dysfunction I: mechanisms and pathophysiology.

The highest incidence of sepsis across all age groups occurs in neonates leading to substantial mortality and morbidity. Cardiovascular dysfunction frequently complicates neonatal sepsis including biventricular systolic and/or diastolic dysfunction, vasoregulatory failure, and pulmonary arterial hypertension. The haemodynamic response in neonatal sepsis can be hyperdynamic or hypodynamic and the underlying pathophysiological mechanisms are heterogeneous. The diagnosis and definition of both neonatal sepsis and cardiovascular dysfunction complicating neonatal sepsis are challenging and not consensus-based. Future developments in neonatal sepsis management will be facilitated by common definitions and datasets especially in neonatal cardiovascular optimisation. IMPACT: Cardiovascular dysfunction is common in neonatal sepsis but there is no consensus-based definition, making calculating the incidence and designing clinical trials challenging. Neonatal cardiovascular dysfunction is related to the inflammatory response, which can directly target myocyte function and systemic haemodynamics.

Differential Alveolar and Systemic Oxygenation during Preterm Resuscitation with 100% Oxygen during Delayed Cord Clamping.

OBJECTIVE: Delayed cord clamping (DCC) and 21 to 30% O2 resuscitation is recommended for preterm infants but is commonly associated with low pulmonary blood flow (Qp) and hypoxia. 100% O2 supplementation during DCC for 60 seconds followed by 30% O2 may increase Qp and oxygen saturation (SpO2). STUDY DESIGN: Preterm lambs (125-127 days of gestation) were resuscitated with 100% O2 with immediate cord clamping (ICC, n = 7) or ICC + 30% O2, and titrated to target SpO2 (n = 7) or DCC + 100% O2 for 60 seconds, which followed by cord clamping and 30% O2 titration (n = 7). Seven preterm (23-27 weeks of gestation) human infants received continuous positive airway pressure (CPAP) + 100% O2 for 60 seconds during DCC, cord clamping, and 30% O2 supplementation after cord clamping. RESULTS: Preterm lambs in the ICC + 100% O2 group resulted in PaO2 (77 ± 25 mm Hg), SpO2 (77 ± 11%), and Qp (27 ± 9 mL/kg/min) at 60 seconds. ICC + 30% O2 led to low Qp (14 ± 3 mL/kg/min), low SpO2 (43 ± 26%), and PaO2 (19 ± 7 mm Hg). DCC + 100% O2 led to similar Qp (28 ± 6 mL/kg/min) as ICC + 100% O2 with lower PaO2. In human infants, DCC + CPAP with 100% O2 for 60 seconds, which followed by weaning to 30% resulted in SpO2 of 92 ± 11% with all infants >80% at 5 minutes with 100% survival without severe intraventricular hemorrhage. CONCLUSION: DCC + 100% O2 for 60 seconds increased Qp probably due to transient alveolar hyperoxia with systemic normoxia due to "dilution" by umbilical venous return. Larger translational and clinical studies are warranted to confirm these findings. KEY POINTS: · Transient alveolar hyperoxia during delayed cord clamping can enhance pulmonary vasodilation.. · Placental transfusion buffers systemic oxygen tension and limits hyperoxia.. · Use of 100% oxygen for 60 seconds during DCC was associated with SpO2 ≥80% by 5 minutes..

Protecting Breastfeeding during the COVID-19 Pandemic.

The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) pandemic has impacted all patient populations including pregnant mothers. There is an incomplete understanding of SARS-CoV-2 pathogenesis and transmission potential at this time and the resultant anxiety has led to variable breastfeeding recommendations for suspected or confirmed mothers with novel coronavirus disease 2019 (COVID-19). Due to the potential concern for transmission of infection from maternal respiratory secretions to the newborn, temporary separation of the maternal-baby dyad, allowing for expressed breast milk to be fed to the infant, was initially recommended but later revised to include breastfeeding by the American Academy of Pediatrics in contrast to international societies, which recommend direct breastfeeding. This separation can have negative health and emotional implications for both mother and baby. Only two publications have reported SARS-CoV-2 in human breast milk but the role of breast milk as a vehicle of transmission of COVID-19 to the newborns still remains unclear and may indeed be providing protective antibodies against SARS-CoV-2 infection even in infected neonates. Other modes of transmission of infection to neonates from infected mothers or any care providers cannot be overemphasized. Symptomatic mothers on hydroxychloroquine can safely breastfeed and no adverse effects were reported in a baby treated with remdesivir in another drug trial. The excretion of sarilumab in human breast milk is unknown at this time. Hence, given the overall safety of breast milk and both short-term and long-term nutritional, immunological, and developmental advantages of breast milk to newborn, breast milk should not be withheld from baby. The setting of maternal care, severity of maternal infection and availability of resources can impact the decision of breastfeeding, the role of shared decision making on breastfeeding between mother and physician needs to be emphasized. We strongly recommend direct breastfeeding with appropriate hygiene precautions unless the maternal or neonatal health condition warrants separation of this dyad. KEY POINTS: · Breastmilk does not appear to play a significant role in transmission of SARS-CoV-2.. · Mother-baby separation has negative health and emotional consequences.. · Mothers with suspected or confirmed COVID-19 can directly breastfeed with appropriate precautions..

Defining Longer-Term Outcomes in an Ovine Model of Moderate Perinatal Hypoxia-Ischemia.

Hypoxic-ischemic encephalopathy (HIE) is the leading cause of neonatal morbidity and mortality worldwide. Approximately 1 million infants born with HIE each year survive with cerebral palsy and/or serious cognitive disabilities. While infants born with mild and severe HIE frequently result in predictable outcomes, infants born with moderate HIE exhibit variable outcomes that are highly unpredictable. Here, we describe an umbilical cord occlusion (UCO) model of moderate HIE with a 6-day follow-up. Near-term lambs (n = 27) were resuscitated after the induction of 5 min of asystole. Following recovery, lambs were assessed to define neurodevelopmental outcomes. At the end of this period, lambs were euthanized, and brains were harvested for histological analysis. Compared with prior models that typically follow lambs for 3 days, the observation of neurobehavioral outcomes for 6 days enabled identification of animals that recover significant neurological function. Approximately 35% of lambs exhibited severe motor deficits throughout the entirety of the 6-day course and, in the most severely affected lambs, developed spastic diparesis similar to that observed in infants who survive severe neonatal HIE (severe, UCOs). Importantly, and similar to outcomes in human neonates, while initially developing significant acidosis and encephalopathy, the remainder of the lambs in this model recovered normal motor activity and exhibited normal neurodevelopmental outcomes by 6 days of life (improved, UCOi). The UCOs group exhibited gliosis and inflammation in both white and gray matters, oligodendrocyte loss, neuronal loss, and cellular death in the hippocampus and cingulate cortex. While the UCOi group exhibited more cellular death and gliosis in the parasagittal cortex, they demonstrated more preserved white matter markers, along with reduced markers of inflammation and lower cellular death and neuronal loss in Ca3 of the hippocampus compared with UCOs lambs. Our large animal model of moderate HIE with prolonged follow-up will help further define pathophysiologic drivers of brain injury while enabling identification of predictive biomarkers that correlate with disease outcomes and ultimately help support development of therapeutic approaches to this challenging clinical scenario.

Placental transfusion during neonatal resuscitation in an asphyxiated preterm model.

BACKGROUND: Neonatal Resuscitation Program does not recommend placental transfusion in depressed preterm neonates. METHODS: Our objectives were to study the effect of delayed cord clamping (DCC) with ventilation for 5 min (DCCV, n-5), umbilical cord milking (UCM) without ventilation (n-6), UCM with ventilation (UCMV, n-6), early cord clamping followed by ventilation (ECCV, n-6) on red cell volume (RCV), and hemodynamic changes in asphyxiated preterm lambs. Twenty-three preterm lambs at 127-128 days gestation were randomized to DCCV, UCM, UCMV, and ECCV. We defined asphyxia as heart rate <100/min. RESULTS: The UCMV had the highest neonatal RCV as a percentage of fetoplacental volume compared to the other groups (UCMV 85.5 ± 10%, UCM 72 ± 10%, ECCV 65 ± 14%, DCCV 61 ± 10%, p < 0.01). The DCCV led to better ventilation (66 ± 1 mmHg) and higher pulmonary blood flow (75 ± 24 ml/kg/min). The carotid flow was significantly higher in UCM without ventilation. The fluctuations in carotid flow with milking were 25 ± 6% higher from baseline during UCM, compared to 6 ± 3% in UCMV (p < 0.01). CONCLUSIONS: Cord milking with ventilation led to higher RCV than other interventions. Ventilation during cord milking reduced fluctuation in carotid flow compared to UCM alone. DCCV led to better ventilation and pulmonary blood flow but did not increase RCV. IMPACT: The best practice of placental transfusion in a depressed preterm neonate remains unknown. Ventilation with an intact cord improves gas exchange and hemodynamics in an asphyxiated preterm model. Cord milking without ventilation led to lower red cell volume but higher carotid blood flow fluctuations compared to milking with ventilation. Our data can be translated to bedside and could impact preterm resuscitation.

Umbilical Cord Milking vs Delayed Cord Clamping and Associations with In-Hospital Outcomes among Extremely Premature Infants.

OBJECTIVE: To compare in-hospital outcomes after umbilical cord milking vs delayed cord clamping among infants <29 weeks of gestation. STUDY DESIGN: Multicenter retrospective study of infants born <29 weeks of gestation from 2016 to 2018 without congenital anomalies who received active treatment at delivery and were exposed to umbilical cord milking or delayed cord clamping. The primary outcome was mortality or severe (grade III or IV) intraventricular hemorrhage (IVH) by 36 weeks of postmenstrual age (PMA). Secondary outcomes assessed at 36 weeks of PMA were mortality, severe IVH, any IVH or mortality, and a composite of mortality or major morbidity. Outcomes were assessed using multivariable regression, incorporating mortality risk factors identified a priori, confounders, and center. A prespecified, exploratory analysis evaluated severe IVH in 2 gestational age strata, 22-246/7 and 25-286/7 weeks. RESULTS: Among 1834 infants, 23.6% were exposed to umbilical cord milking and 76.4% to delayed cord clamping. The primary outcome, mortality or severe IVH, occurred in 21.1% of infants: 28.3% exposed to umbilical cord milking and 19.1% exposed to delayed cord clamping, with an aOR that was similar between groups (aOR 1.45, 95% CI 0.93, 2.26). Infants exposed to umbilical cord milking had higher odds of severe IVH (19.8% umbilical cord milking vs 11.8% delayed cord clamping, aOR 1.70 95% CI 1.20, 2.43), as did the 25-286/7 week stratum (14.8% umbilical cord milking vs 7.4% delayed cord clamping, aOR 1.89 95% CI 1.22, 2.95). Other secondary outcomes were similar between groups. CONCLUSIONS: This analysis of extremely preterm infants suggests that delayed cord clamping is the preferred practice for placental transfusion, as umbilical cord milking exposure was associated with an increase in the adverse outcome of severe IVH. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00063063.

Continuous chest compressions with asynchronous ventilations increase carotid blood flow in the perinatal asphyxiated lamb model.

BACKGROUND: The neonatal resuscitation program (NRP) recommends interrupted chest compressions (CCs) with ventilation in the severely bradycardic neonate. The conventional 3:1 compression-to-ventilation (C:V) resuscitation provides 90 CCs/min, significantly lower than the intrinsic newborn heart rate (120-160 beats/min). Continuous CC with asynchronous ventilation (CCCaV) may improve the success of return of spontaneous circulation (ROSC). METHODS: Twenty-two near-term fetal lambs were randomized to interrupted 3:1 C:V (90 CCs + 30 breaths/min) or CCCaV (120 CCs + 30 breaths/min). Asphyxiation was induced by cord occlusion. After 5 min of asystole, resuscitation began following NRP guidelines. The first dose of epinephrine was given at 6 min. Invasive arterial blood pressure and left carotid blood flow were continuously measured. Serial arterial blood gases were collected. RESULTS: Baseline characteristics between groups were similar. Rate of and time to ROSC was similar between groups. CCCaV was associated with a higher PaO2 (partial oxygen tension) (22 ± 5.3 vs. 15 ± 3.5 mmHg, p < 0.01), greater left carotid blood flow (7.5 ± 3.1 vs. 4.3 ± 2.6 mL/kg/min, p < 0.01) and oxygen delivery (0.40 ± 0.15 vs. 0.13 ± 0.07 mL O2/kg/min, p < 0.01) compared to 3:1 C:V. CONCLUSIONS: In a perinatal asphyxiated cardiac arrest lamb model, CCCaV showed greater carotid blood flow and cerebral oxygen delivery compared to 3:1 C:V resuscitation. IMPACT: In a perinatal asphyxiated cardiac arrest lamb model, CCCaV improved carotid blood flow and oxygen delivery to the brain compared to the conventional 3:1 C:V resuscitation. Pre-clinical studies assessing neurodevelopmental outcomes and tissue injury comparing continuous uninterrupted chest compressions to the current recommended 3:1 C:V during newborn resuscitation are warranted prior to clinical trials.

Randomized trial of oxygen weaning strategies following chest compressions during neonatal resuscitation.

BACKGROUND: The Neonatal Resuscitation Program (NRP) recommends using 100% O2 during chest compressions and adjusting FiO2 based on SpO2 after return of spontaneous circulation (ROSC). The optimal strategy for adjusting FiO2 is not known. METHODS: Twenty-five near-term lambs asphyxiated by umbilical cord occlusion to cardiac arrest were resuscitated per NRP. Following ROSC, lambs were randomized to gradual decrease versus abrupt wean to 21% O2 followed by FiO2 titration to achieve NRP SpO2 targets. Carotid blood flow and blood gases were monitored. RESULTS: Three minutes after ROSC, PaO2 was 229 ± 32 mmHg in gradual wean group compared to 57 ± 13 following abrupt wean to 21% O2 (p < 0.001). PaO2 remained high in the gradual wean group at 10 min after ROSC (110 ± 10 vs. 67 ± 12, p < 0.01) despite similar FiO2 (~0.3) in both groups. Cerebral O2 delivery (C-DO2) was higher above physiological range following ROSC with gradual wean (p < 0.05). Lower blood oxidized/reduced glutathione ratio (suggesting less oxidative stress) was observed with abrupt wean. CONCLUSION: Weaning FiO2 abruptly to 0.21 with adjustment based on SpO2 prevents surge in PaO2 and C-DO2 and minimizes oxidative stress compared to gradual weaning from 100% O2 following ROSC. Clinical trials with neurodevelopmental outcomes comparing post-ROSC FiO2 weaning strategies are warranted. IMPACT: In a lamb model of perinatal asphyxial cardiac arrest, abrupt weaning of inspired oxygen to 21% prevents excessive oxygen delivery to the brain and oxidative stress compared to gradual weaning from 100% oxygen following return of spontaneous circulation. Clinical studies assessing neurodevelopmental outcomes comparing abrupt and gradual weaning of inspired oxygen after recovery from neonatal asphyxial arrest are warranted.

Optimal Oxygen Targets in Term Lambs with Meconium Aspiration Syndrome and Pulmonary Hypertension.

Optimal oxygen saturation as measured by pulse oximetry (SpO2) in neonatal lung injury, such as meconium aspiration syndrome (MAS) and persistent pulmonary hypertension of newborn (PPHN), is not known. Our goal was to determine the SpO2 range in lambs with MAS and PPHN that results in the highest brain oxygen delivery (bDO2) and pulmonary blood flow (Qp) and the lowest pulmonary vascular resistance and oxidative stress. Meconium was instilled into endotracheal tubes in 25 near-term gestation lambs, and the umbilical cord was occluded to induce asphyxia and gasping, causing MAS and PPHN. Lambs were randomized into four groups and ventilated for 6 hours with fixed fraction of inspired oxygen (FiO2) = 1.0 irrespective of SpO2, and three groups had FiO2 titrated to keep preductal SpO2 between 85% and 89%, 90% and 94%, and 95% and 99%, respectively. Tissues were collected to measure nitric oxide synthase activity, 3-nitrotyrosine, and 8-isoprostanes. Throughout the 6-hour exposure period, lambs in the 95-99% SpO2 target group had the highest Qp, lowest pulmonary vascular resistance, and highest bDO2 but were exposed to higher FiO2 (0.5 ± 0.21 vs. 0.29 ± 0.17) with higher lung 3-nitrotyrosine (0.67 [interquartile range (IQR), 0.43-0.73] ng/mcg protein vs. 0.1 [IQR, 0.09-0.2] ng/mcg protein) and lower lung nitric oxide synthase activity (196 [IQR, 192-201] mMol nitrite/mg protein vs. 270 [IQR, 227-280] mMol nitrite/mg protein) compared with the 90-94% target group. Brain 3-nitrotyrosine was lower in the 85-89% target group, and brain/lung 8-isoprostane levels were not significantly different. In term lambs with MAS and PPHN, Qp and bDO2 through the first 6 hours are higher with target SpO2 in the 95-99% range. However, the 90-94% target range is associated with significantly lower FiO2 and lung oxidative stress. Clinical trials comparing the 90-94% versus the 95-99% SpO2 target range in term infants with PPHN are warranted.

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.