Changes in e-cigarette and cigarette use during pregnancy and their association with small-for-gestational-age birth.

BACKGROUND: Despite increased e-cigarette use, limited research has focused on changes in e-cigarette and combustible cigarette use around pregnancy and the subsequent effects on infant health. OBJECTIVE: This study aimed to characterize changes in e-cigarette and cigarette use from before to during pregnancy and examine their associations with small-for-gestational-age birth. STUDY DESIGN: This was a secondary data analysis of 2016-2018 data of the US Pregnancy Risk Assessment Monitoring System. We analyzed women aged ≥18 years who had a recent live birth (unweighted: n=105,438; weighted: n=5,446,900). Women were grouped on the basis of their self-reported e-cigarette and/or cigarette use 3 months before pregnancy (exclusive e-cigarette users, exclusive cigarette smokers, dual users, and nonusers) and change in e-cigarette and cigarette use during pregnancy (continuing use, quitting, switching, and initiating use). Small-for-gestational-age was defined as a birthweight below the 10th percentile for infants of the same sex and gestational age. We described the distributions of women's sociodemographic and pregnancy characteristics in both weighted and unweighted samples. We used multivariable log-binomial regression models to estimate the relative risks for the associations between changes in e-cigarette and cigarette use during pregnancy and risk of small-for-gestational-age, adjusting for significant covariates. RESULTS: The rates of cessation during pregnancy were the highest among exclusive e-cigarette users (weighted percentage, 80.7% [49,378/61,173]), followed by exclusive cigarette users (54.4% [421,094/773,586]) and dual users (46.4% [69,136/149,152]). Among exclusive e-cigarette users, continued users of e-cigarettes during pregnancy had a higher risk of small-for-gestational-age than nonusers (16.5% [1849/11,206]) vs 8.8% [384,338/4,371,664]; confounder-adjusted relative risk, 1.52 [95% confidence interval, 1.45-1.60]), whereas quitters of e-cigarettes had a similar risk of small-for-gestational-age with nonusers (7.7% [3730/48,587] vs 8.8% [384,338/4,371,664]; relative risk, 0.84 [95% confidence interval, 0.82-0.87]). Among exclusive cigarette users, those who completely switched to e-cigarettes during pregnancy also had a similar risk of small-for-gestational-age with nonusers (7.6% [259/3412] vs 8.8% [384,338/4,371,664]; relative risk, 0.83 [95% confidence interval, 0.73-0.93]). Among dual users before pregnancy, the risk of small-for-gestational-age decreased from 23.2% (7240/31,208) (relative risk, 2.53 [95% confidence interval, 2.47-2.58]) if continuing use to 16.9% (6617/39,142) (relative risk, 1.88 [95% confidence interval, 1.83-1.92]) if only quitting e-cigarettes or 15.1% (1254/8289) (relative risk, 1.61 [95% confidence interval, 1.52-1.70]) if only quitting cigarettes and further to 11.2% (7589/67,880) (relative risk, 1.23 [95% confidence interval, 1.20-1.25]) if both quitting e-cigarettes and cigarettes during pregnancy, compared with nonusers. CONCLUSION: Among exclusive e-cigarette users, quitting e-cigarettes during pregnancy normalized the risk of small-for-gestational-age. Among exclusive cigarette users, quitting smoking or completely switching to e-cigarettes normalized small for gestational age risk. Among dual users, smoking cessation has a greater effect than quitting e-cigarettes only, although discontinuing the use of both may lead to the greatest reduction in the risk of small-for-gestational-age.

Increased prevalence of severe neonatal hyperbilirubinaemia during social distancing.

AIM: Social distancing guidelines implemented with the COVID-19 pandemic impacted health-care utilisation and disrupted critical social supports. Resurgence of highly transmissible strains has resulted in revisiting restrictions with potential impacts on newborn health. With concerns for inadequate post-partum support, we sought to determine if social distancing correlated with increased rates of readmission for hyperbilirubinaemia. METHODS: Retrospective chart review identified all readmissions for hyperbilirubinaemia between 1/18 and 4/20 in Western New York. Infant/maternal demographics and data on hospital course were collected on control (1/1/18-31/1/20) and social distancing (1/2/20-30/4/20) cohorts. Nineteen outpatient clinics were surveyed regarding lactation support. RESULTS: Monthly readmissions for hyperbilirubinaemia nearly tripled during social distancing (0.90 ± 0.91 vs. 2.63 ± 2.29 per 1000 births during early COVID, P = 0.015). Comparable severity of disease at readmission was observed with no difference in the need for therapies (phototherapy, intravenous immunoglobulin or exchange transfusion) or length of hospital stay. Mothers were younger (25.8 ± 3.3 vs. 31.3 ± 4.7 years; P = 0.005) with higher rates of primiparity and exclusive breastfeeding than national norms, however not significantly higher than controls in our small cohort (62.5 vs. 37.0% for primiparity; 87.5 vs. 81.5% for breastfeeding). Of 19 clinics surveyed, only six confirmed a telemedicine option for lactation support. CONCLUSIONS: Rates of readmission for hyperbilirubinaemia increased during social distancing. Younger maternal age with high rates of primiparity and exclusive breastfeeding raise concern for inadequate social and/or lactation support. Proactive identification of mothers at risk and expansion of remote lactation services may be indicated with recurrent waves of the pandemic.

A multicenter study of incidence, risk factors and outcomes of babies with birth asphyxia in Nepal.

BACKGROUND: Perinatal events which result in compromised oxygen delivery to the fetus can lead to Birth Asphyxia (BA). While the incidence, risk factors and outcomes of BA have been characterized, less is known in low resource settings. AIM: To determine the incidence of Birth Asphyxia (BA) in Nepal and to evaluate associated risk factors and outcomes of this condition. METHODS: A nested observational study was conducted in 12 hospitals of Nepal for a period of 14 months. Babies diagnosed as BA at ≥37 weeks of gestation were identified and demographics were reviewed. Data were analyzed using binary logistic regression followed by multiple logistic regression analysis. RESULTS: The incidence of BA in this study was 6 per 1000 term livebirths and was higher among women 35 years and above. Predictors for BA were instrumented vaginal delivery (aOR:4.4, 95% CI, 3.1-6.1), fetal distress in labour (aOR:1.9, 95% CI, 1.0-3.6), malposition (aOR:1.8, 95% CI, 1.0-3.0), birth weight less than 2500 g (aOR:2.0, 95% CI, 1.3-2.9), gestational age ≥ 42 weeks (aOR:2.0, 95% CI, 1.3-3.3) and male gender (aOR:1.6, 95% CI, 1.2-2.0). The risk of pre-discharge mortality was 43 times higher in babies with BA (aOR:42.6, 95% CI, 32.2-56.3). CONCLUSION: The incidence of Birth asphyxia in Nepal higher than in more resourced setting. A range of obstetric and neonatal risk factors are associated with BA with an associated high risk of pre-discharge mortality. Interventions to improve management and decrease rates of BA could have marked impact on outcomes in low resource settings.

Effects of Neonatal Caffeine Administration on Vessel Reactivity in Adult Mice.

OBJECTIVE: The effects of neonatal caffeine therapy in adults born preterm are uncertain. We studied the impact of neonatal caffeine on systemic blood pressure, vessel reactivity, and response to stress in adult mice. STUDY DESIGN: Mice pups were randomized to caffeine (20 mg/kg/d) or saline by intraperitoneal injection for 10 days after birth. We performed tail-cuff BP (8/12 weeks), urinary 8-hydroxydeoxyguanosine and fecal corticosterone (14 weeks), and vessel reactivity in aortic rings (16 weeks) in adult mice. RESULTS: No differences were noted in systolic, diastolic, and mean blood pressures between the two groups at 8 and 12 weeks of age. However, norepinephrine-induced vasoconstriction was substantially higher in aortic rings in CAF-treated male mice. More significant vasodilator responses to nitric oxide donors in aortic rings in female mice may suggest gender-specific effects of caffeine. Female mice exposed to caffeine had significantly lower body weight over-time. Caffeine-treated male mice had substantially higher fecal corticosterone and urinary 8-hydroxydeoxyguanosine at 14 weeks, suggestive of chronic stress. CONCLUSION: We conclude sex-specific vulnerability to the heightened vascular tone of the aorta in male mice following neonatal caffeine therapy. Altered vessel reactivity and chronic stress in the presence of other risk factors may predispose to the development of systemic hypertension in adults born preterm.

Impaired Autophagic Activity Contributes to the Pathogenesis of Bronchopulmonary Dysplasia. Evidence from Murine and Baboon Models.

Bronchopulmonary dysplasia (BPD) is a common and serious complication associated with preterm birth. The pathogenesis of BPD is incompletely understood, and there is an unmet clinical need for effective treatments. The role of autophagy as a potential cytoprotective mechanism in BPD remains to be fully elucidated. In the present study, we investigated the role and regulation of autophagy in experimental models of BPD. Regulation and cellular distribution of autophagic activity during postnatal lung development and in neonatal hyperoxia-induced lung injury (nHILI) were assessed in the autophagy reporter transgenic GFP-LC3 (GFP-microtubule-associated protein 1A/1B-light chain 3) mouse model. Autophagic activity and its regulation were also examined in a baboon model of BPD. The role of autophagy in nHILI was determined by assessing lung morphometry, injury, and inflammation in autophagy-deficient Beclin 1 heterozygous knockout mice (Becn1+/-). Autophagic activity was induced during alveolarization in control murine lungs and localized primarily to alveolar type II cells and macrophages. Hyperoxia exposure of neonatal murine lungs and BPD in baboon lungs resulted in impaired autophagic activity in association with insufficient AMPK (5'-AMP-activated protein kinase) and increased mTORC1 (mTOR complex 1) activation. Becn1+/- lungs displayed impaired alveolarization, increased alveolar septal thickness, greater neutrophil accumulation, and increased IL-1ß concentrations when exposed to nHILI. Becn1+/- alveolar macrophages isolated from nHILI-exposed mice displayed increased expression of proinflammatory genes. In conclusion, basal autophagy is induced during alveolarization and disrupted during progression of nHILI in mice and BPD in baboons. Becn1+/- mice are more susceptible to nHILI, suggesting that preservation of autophagic activity may be an effective protective strategy in BPD.

The burden of and factors associated with misclassification of intrapartum stillbirth: Evidence from a large scale multicentric observational study.

INTRODUCTION: Global estimates suggest 2.6 million stillbirths and 2.5 million neonatal deaths occur annually worldwide. The majority of these deaths occur in low resource settings where analysis of health metrics and outcomes measurements may be challenging. We examined the misclassification of documented intrapartum stillbirth and factors associated with misclassification. MATERIAL AND METHODS: A prospective observational study was performed in 12 public hospitals in Nepal. Data were extracted from the medical records of all births that occurred during the 6-month period of the study. For the study purpose, we classified birth outcome based on the presence of fetal heart sound (FHS) at admission and use of neonatal resuscitation. The health worker-documented intrapartum stillbirths were considered potentially misclassified when there were FHS present at admission and no resuscitation initiated after birth. The association between potentially misclassified intrapartum stillbirth and complications during labor, birthweight and gestational age was assessed using Pearson's chi-square test, bivariate and multivariate logistic regression. RESULTS: A total of 39 562 mother-infant dyads were enrolled in the study, all of whom had FHS at admission. Among the 391 intrapartum stillbirths recorded during the study, 180 (46.0%) of them had FHS at admission with no resuscitation initiated after birth and were considered potentially misclassified intrapartum stillbirths. Among these potentially misclassified intrapartum stillbirths, 170 (43.5%) had FHS present 15 minutes before birth and 10 had no FHS 15 minutes before birth Among the potentially misclassified intrapartum stillbirths, 23.3% had complications during labor, 93.3% had birthweight less than 2500 g and 90.0% were born preterm. The risk of intrapartum misclassification was nearly four times higher among low birthweight babies (adjusted odds ratio [aOR] 3.5, 95% confidence interval [CI] 1.8 to 7.0, P < 0.001) and five times higher among preterm babies (aOR 5.3, 95% CI 3.0 to 9.3, P < 0.001). CONCLUSIONS: We estimate that 46% of intrapartum stillbirths were potentially misclassified intrapartum stillbirths. Improving quality of both FHS monitoring and neonatal resuscitation as well as measurement of the care will reduce the risk of potentially misclassified intrapartum stillbirth and consequently intrapartum stillbirth.

Effects of Partially Hydrolyzed Formula on Severity and Outcomes of Neonatal Abstinence Syndrome.

OBJECTIVE: This study compares the effect of partially hydrolyzed formula (PHF) and standard formula (SF) on the severity and short-term outcomes of neonatal abstinence syndrome (NAS). STUDY DESIGN: We performed a retrospective chart review of 124 opioid-dependent mothers and their term or near-term infants. Infants were categorized according to the predominant type of formula consumed during the hospital stay. Finnegan's scale was used to assess symptoms of withdrawal. RESULTS: A total of 110 infants met our inclusion criteria. Thirty-four (31%) infants were fed predominantly PHF, 60 (54%) infants were fed SF, and 16 (15%) infants were fed maternal breast milk. There was no difference between the infants in the PHF and SF groups with respect to requirement of morphine (MSO4) therapy, maximum dose of MSO4 used, duration of MSO4 treatment or length of hospital stay after performing multivariate analyses to control for type of drug used by the mother, maternal smoking, regular prenatal care, inborn status, and maximum Finnegan score prior to MSO4 treatment. CONCLUSION: Use of PHF failed to impact short-term outcomes in infants treated for NAS including maximum MSO4 dose, duration of MSO4 treatment, and length of hospital stay. A prospective randomized controlled trial may be indicated to confirm this finding.

Revisiting: "A pre-post study of a multi-country scale up of resuscitation training of facility birth attendants: does helping babies breathe training save lives?"

BACKGROUND: Helping Babies Breathe (HBB) is a low cost, skills-based neonatal resuscitation education program designed specifically for use in low resource settings. Studies from Tanzania, India and Nepal have demonstrated that HBB training results in decreased rates of fresh still birth and/or neonatal mortality. However, less is known regarding the impact of training on neonatal mortality at a population level. Bellad et al. utilized (BMC Pregnancy Childbirth. 2016;16 (1):222) utilized population based registries to evaluate outcomes before and after training of facility birth attendants. Their study entitled "A pre-post study of a multi-country scale up of resuscitation training of facility birth attendants: Does Helping Babies Breathe training save lives?" suggested facility based training was not associated with consistent improvements in neonatal mortality on a population level. DISCUSSION: Combining outcomes from three diverse settings may have under-estimated the impact of HBB training. We remain concerned that the modest benefits observed in the Kenyan site were lost with compiling of data. The statement that HBB "was not associated with consistent improvements in mortality" may lead to the mistaken conclusion that improvements in neonatal mortality were not seen, when in fact, they were in selected cohorts. With numerous studies demonstrating potential for reduced neonatal mortality as a result of HBB training, we encourage interpretation of these findings in the context of local care.

Direct hyperbilirubinemia in newborns with gastroschisis.

BACKGROUND: Patients with gastroschisis and prolonged total (or partial) parenteral nutrition (PN) commonly develop direct hyperbilirubinemia (DH). OBJECTIVE: To quantify the prevalence and severity of DH in newborns with gastroschisis and characterize the diagnostic work-up for DH in this patient population. DESIGN/METHODS: Retrospective chart review of patients born with gastroschisis between 2005 and 2015 for the first 6 months of life. RESULTS: 29 patients were identified with gastroschisis. Mean gestational age and birthweight were 36.4 (± 1.8) weeks and 2.5 (± 0.6) kg. 41% were treated with primary reduction versus staged closure. Peak total and direct bilirubin (DB) levels were 10.17 ± 6.21 mg/dL and 5.58 ± 3.94 mg/dL, respectively. 23 patients (79.3%) were diagnosed with DH and 78.2% underwent additional work-up for hyperbilirubinemia consisting of imaging and laboratory studies, none of which revealed a cause for DH other than the presumed PN-associated cholestasis. In all patients, DB began to decline within 1-10 days of initiation of enteral feeds. CONCLUSION(S): DH is common in patients with gastroschisis and is unlikely to be associated with pathology aside from PN. Additional work-up may lead to unnecessary resource utilization. LEVELS OF EVIDENCE: Case series with no comparison group, Level IV.

Neonatal resuscitation in global health settings: an examination of the past to prepare for the future.

As rates of childhood mortality decline, neonatal deaths account for nearly half of under-5 deaths worldwide. Intrapartum-related events (birth asphyxia) contribute to approximately one-quarter of neonatal deaths, many of which can be prevented by simple resuscitation and newborn care interventions. This paper reviews various lines of research that have influenced the global neonatal resuscitation landscape. A brief situational analysis of asphyxia-related newborn mortality in low-resource settings is linked to renewed efforts to reduce neonatal mortality in the Every Newborn Action Plan. Possible solutions to gaps in care are identified. Building on international scientific evidence, tests of educational efficacy, and community-based trials established the feasibility and effectiveness of training in resource-limited settings and identified successful implementation strategies. Implementation of neonatal resuscitation programs has been shown to decrease intrapartum stillbirth rates and early neonatal mortality. Challenges remain with respect to provider competencies, coverage, and quality of interventions. The combination of resuscitation science, strategies to increase educational effectiveness, and implemention of interventions with high coverage and quality has resulted in reduced rates of asphyxia-related neonatal mortality. Further efforts to improve coverage and implementation of neonatal resuscitation will be necessary to meet the 2035 goal of eliminating preventable newborn deaths.

Continuous capnography monitoring during resuscitation in a transitional large mammalian model of asphyxial cardiac arrest.

BACKGROUND: In neonates requiring chest compression (CC) during resuscitation, neonatal resuscitation program (NRP) recommends against relying on a single feedback device such as end-tidal carbon dioxide (ETCO2) or saturations (SpO2) to determine return of spontaneous circulation (ROSC) until more evidence becomes available. METHODS: We evaluated the role of monitoring ETCO2 during resuscitation in a lamb model of cardiac arrest induced by umbilical cord occlusion (n = 21). Lambs were resuscitated as per NRP guidelines. Systolic blood pressure (SBP), carotid and pulmonary blood flows along with ETCO2 and blood gases were continuously monitored. Resuscitation was continued for 20 min or until ROSC (whichever was earlier). Adequate CC was arbitrarily defined as generation of 30 mmHg SBP during resuscitation. ETCO2 thresholds to predict adequacy of CC and detect ROSC were determined. RESULTS: Significant relationship between ETCO2 and adequate CC was noted during resuscitation (AUC-0.735, P < 0.01). At ROSC (n = 12), ETCO2 rapidly increased to 57 ± 20 mmHg with a threshold of ≥32 mmHg being 100% sensitive and 97% specific to predict ROSC. CONCLUSION: In a large mammalian model of perinatal asphyxia, continuous ETCO2 monitoring predicted adequacy of CC and detected ROSC. These findings suggest ETCO2 in conjunction with other devices may be beneficial during CC and predict ROSC.

Continuous Chest Compressions During Sustained Inflations in a Perinatal Asphyxial Cardiac Arrest Lamb Model.

OBJECTIVE: Continuous chest compressions are more effective during resuscitation in adults. Sustained inflation rapidly establishes functional residual capacity in fluid-filled lungs at birth. We sought to compare the hemodynamics and success in achieving return of spontaneous circulation in an asphyxial cardiac arrest lamb model with transitioning fetal circulation and fluid-filled lungs between subjects receiving continuous chest compressions during sustained inflation and those receiving conventional 3:1 compression-to-ventilation resuscitation. DESIGN: Prospective, randomized, animal model study. SETTING: An experimental laboratory. SUBJECTS: Fourteen newborn term gestation lambs. INTERVENTIONS: Lambs were randomized into two groups: 3:1 compression-to-ventilation (control) and continuous chest compressions during sustained inflation. The umbilical cord was occluded to induce asphyxia and asystole. The control group was resuscitated per NRP guidelines. In the sustained inflation + continuous chest compressions group, sustained inflation at 35 cm H2O was provided for 30 seconds with 1-second interruptions before another sustained inflation was provided. One hundred twenty chest compressions/min started after the initial sustained inflation. The first dose of IV epinephrine was given at 6 minutes if return of spontaneous circulation was not achieved and then every 3 minutes until return of spontaneous circulation or for a total of four doses. MEASUREMENT AND RESULTS: All lambs achieved return of spontaneous circulation in a comparable median time (interquartile range) of 390 seconds (225-405 s) and 345 seconds (204-465 s) in the sustained inflation + continuous chest compressions and control groups, respectively. Four of seven (sustained inflation + continuous chest compressions) and three of six (control) lambs required epinephrine to achieve return of spontaneous circulation. Diastolic blood pressures were lower in the sustained inflation + continuous chest compressions (4 ± 2 mm Hg) compared to the control group (7 ± 2 mm Hg), p < 0.05. PaCO2, PaO2, and lactate were similar between the groups during the study period. CONCLUSION: In this perinatal cardiac arrest lamb model with transitioning fetal circulation and fluid-filled lungs, sustained inflation + continuous chest compressions is as effective as 3:1 compression-to-ventilation resuscitation in achieving return of spontaneous circulation. Half the lambs achieved return of spontaneous circulation without epinephrine. continuous chest compressions during sustained inflation reduced diastolic pressures but did not alter gas exchange or carotid blood flow compared to 3:1 compression-to-ventilation resuscitation.

Postnatal growth restriction augments oxygen-induced pulmonary hypertension in a neonatal rat model of bronchopulmonary dysplasia.

BACKGROUND: Prematurity and fetal growth restriction are risk factors for pulmonary hypertension (PH) in infants with bronchopulmonary dysplasia (BPD). Neonatal rats develop PH and vascular remodeling when exposed to hyperoxia. We hypothesize that postnatal growth restriction (PNGR) due to under-nutrition increases the severity of PH induced by hyperoxia in neonatal rats. METHODS: Pups were randomized at birth to litters maintained in room air or 75% oxygen (hyperoxia), together with litters of normal milk intake (10 pups) or PNGR (17 pups). After 14 d, right ventricular hypertrophy (RVH) was assessed by Fulton's index (right ventricular weight/left ventricular plus septal weight) and PH by echocardiography. Lungs were analyzed by immunohistochemistry, morphometrics, western blotting, and metabolomics. RESULTS: Hyperoxia and PNGR each significantly increased pulmonary arterial pressure, RVH and pulmonary arterial medial wall thickness, and significantly decreased pulmonary vessel number. These changes were significantly augmented in pups exposed to both insults. Hyperoxia and PNGR both significantly decreased expression of proteins involved in lung development and vasodilation. CONCLUSION: PNGR induces right ventricular and pulmonary vascular remodeling and augments the effects of oxygen in neonatal rats. This may be a powerful tool to investigate the mechanisms that induce PH in low-birth-weight preterm infants with BPD.

Mouse lung development and NOX1 induction during hyperoxia are developmentally regulated and mitochondrial ROS dependent.

Animal models demonstrate that exposure to supraphysiological oxygen during the neonatal period compromises both lung and pulmonary vascular development, resulting in a phenotype comparable to bronchopulmonary dysplasia (BPD). Our prior work in murine models identified postnatal maturation of antioxidant enzyme capacities as well as developmental regulation of mitochondrial oxidative stress in hyperoxia. We hypothesize that consequences of hyperoxia may also be developmentally regulated and mitochondrial reactive oxygen species (ROS) dependent. To determine whether age of exposure impacts the effect of hyperoxia, neonatal mice were placed in 75% oxygen for 72 h at either postnatal day 0 (early postnatal) or day 4 (late postnatal). Mice exposed to early, but not late, postnatal hyperoxia demonstrated decreased alveolarization and septation, increased muscularization of resistance pulmonary arteries, and right ventricular hypertrophy (RVH) compared with normoxic controls. Treatment with a mitochondria-specific antioxidant, (2-(2,2,6,6-tetramethylpiperidin-1-oxyl-4-ylamino)-2-oxoethyl)triphenylphosphonium chloride (mitoTEMPO), during early postnatal hyperoxia protected against compromised alveolarization and RVH. In addition, early, but not late, postnatal hyperoxia resulted in induction of NOX1 expression that was mitochondrial ROS dependent. Because early, but not late, exposure resulted in compromised lung and cardiovascular development, we conclude that the consequences of hyperoxia are developmentally regulated and decrease with age. Attenuated disease in mitoTEMPO-treated mice implicates mitochondrial ROS in the pathophysiology of neonatal hyperoxic lung injury, with potential for amplification of ROS signaling through NOX1 induction. Furthermore, it suggests a potential role for targeted antioxidant therapy in the prevention or treatment of BPD.

Right ventricular cyclic nucleotide signaling is decreased in hyperoxia-induced pulmonary hypertension in neonatal mice.

Pulmonary hypertension (PH) and right ventricular hypertrophy (RVH) affect 25-35% of premature infants with significant bronchopulmonary dysplasia (BPD), increasing morbidity and mortality. We sought to determine the role of phosphodiesterase 5 (PDE5) in the right ventricle (RV) and left ventricle (LV) in a hyperoxia-induced neonatal mouse model of PH and RVH. After birth, C57BL/6 mice were placed in room air (RA) or 75% O2 (CH) for 14 days to induce PH and RVH. Mice were euthanized at 14 days or recovered in RA for 14 days or 42 days prior to euthanasia at 28 or 56 days of age. Some pups received sildenafil or vehicle (3 mg·kg(-1)·dose(-1) sc) every other day from P0. RVH was assessed by Fulton's index [RV wt/(LV + septum) wt]. PDE5 protein expression was analyzed via Western blot, PDE5 activity was measured by commercially available assay, and cGMP was measured by enzyme-linked immunoassay. Hyperoxia induced RVH in mice after 14 days, and RVH did not resolve until 56 days of age. Hyperoxia increased PDE5 expression and activity in RV, but not LV + S, after 14 days. PDE5 expression normalized by 28 days of age, but PDE5 activity did not normalize until 56 days of age. Sildenafil given during hyperoxia prevented RVH, decreased RV PDE5 activity, and increased RV cGMP levels. Mice with cardiac-specific overexpression of PDE5 had increased RVH in RA. These findings suggest normal RV PDE5 function is disrupted by hyperoxia, and elevated PDE5 contributes to RVH and remodeling. Therefore, in addition to impacting the pulmonary vasculature, sildenafil also targets PDE5 in the neonatal mouse RV and decreases RVH.

Regulation of hypoxia-induced pulmonary hypertension by vascular smooth muscle hypoxia-inducible factor-1α.

RATIONALE: Chronic hypoxia induces pulmonary vascular remodeling, pulmonary hypertension, and right ventricular hypertrophy. At present, little is known about mechanisms driving these responses. Hypoxia-inducible factor-1α (HIF-1α) is a master regulator of transcription in hypoxic cells, up-regulating genes involved in energy metabolism, proliferation, and extracellular matrix reorganization. Systemic loss of a single HIF-1α allele has been shown to attenuate hypoxic pulmonary hypertension, but the cells contributing to this response have not been identified. OBJECTIVES: We sought to determine the contribution of HIF-1α in smooth muscle on pulmonary vascular and right heart responses to chronic hypoxia. METHODS: We used mice with homozygous conditional deletion of HIF-1α combined with tamoxifen-inducible smooth muscle-specific Cre recombinase expression. Mice received either tamoxifen or vehicle followed by exposure to either normoxia or chronic hypoxia (10% O2) for 30 days before measurement of cardiopulmonary responses. MEASUREMENTS AND MAIN RESULTS: Tamoxifen-induced smooth muscle-specific deletion of HIF-1α attenuated pulmonary vascular remodeling and pulmonary hypertension in chronic hypoxia. However, right ventricular hypertrophy was unchanged despite attenuated pulmonary pressures. CONCLUSIONS: These results indicate that HIF-1α in smooth muscle contributes to pulmonary vascular remodeling and pulmonary hypertension in chronic hypoxia. However, loss of HIF-1 function in smooth muscle does not affect hypoxic cardiac remodeling, suggesting that the cardiac hypertrophy response is not directly coupled to the increase in pulmonary artery pressure.

Evaluation of an educational program for essential newborn care in resource-limited settings: Essential Care for Every Baby.

BACKGROUND: Essential Care for Every Baby (ECEB) is an evidence-based educational program designed to increase cognitive knowledge and develop skills of health care professionals in essential newborn care in low-resource areas. The course focuses on the immediate care of the newborn after birth and during the first day or until discharge from the health facility. This study assessed the overall design of the course; the ability of facilitators to teach the course; and the knowledge and skills acquired by the learners. METHODS: Testing occurred at 2 global sites. Data from a facilitator evaluation survey, a learner satisfaction survey, a multiple choice question (MCQ) examination, performance on two objective structured clinical evaluations (OSCE), and pre- and post-course confidence assessments were analyzed using descriptive statistics. Pre-post course differences were examined. Comments on the evaluation form and post-course group discussions were analyzed to identify potential program improvements. RESULTS: Using ECEB course material, master trainers taught 12 facilitators in India and 11 in Kenya who subsequently taught 62 providers of newborn care in India and 64 in Kenya. Facilitators and learners were satisfied with their ability to teach and learn from the program. Confidence (3.5 to 5) and MCQ scores (India: pre 19.4, post 24.8; Kenya: pre 20.8, post 25.0) improved (p < 0.001). Most participants demonstrated satisfactory skills on the OSCEs. Qualitative data suggested the course was effective, but also identified areas for course improvement. These included additional time for hands-on practice, including practice in a clinical setting, the addition of video learning aids and the adaptation of content to conform to locally recommended practices. CONCLUSION: ECEB program was highly acceptable, demonstrated improved confidence, improved knowledge and developed skills. ECEB may improve newborn care in low resource settings if it is part of an overall implementation plan that addresses local needs and serves to further strengthen health systems.

Disrupted pulmonary artery cyclic guanosine monophosphate signaling in mice with hyperoxia-induced pulmonary hypertension.

Pulmonary hypertension (PH) occurs in 25 to 35% of premature infants with significant bronchopulmonary dysplasia (BPD). Neonatal mice exposed to 14 days of hyperoxia develop BPD-like lung injury and PH. To determinne the impact of hyperoxia on pulmonary artery (PA) cyclic guanosine monophosphate (cGMP) signaling in a murine model of lung injury and PH, neonatal C57BL/6 mice were placed in room air, 75% O2 for 14 days (chronic hyperoxia [CH]) or 75% O2 for 24 hours, followed by 13 days of room air (acute hyperoxia with recovery [AHR]) with or without sildenafil. At 14 days, mean alveolar area, PA medial wall thickness (MWT), right ventricular hypertrophy (RVH), and vessel density were assessed. PA protein was analyzed for cGMP, soluble guanylate cyclase, and PDE5 activity. CH and AHR mice had RVH, but only CH mice had increased alveolar area and MWT and decreased vessel density. In CH and AHR PAs, soluble guanylate cyclase activity was decreased, and PDE5 activity was increased. In CH mice, sildenafil attenuated MWT and RVH but did not improve mean alveolar area or vessel density. In CH and AHR PAs, sildenafil decreased PDE5 activity and increased cGMP. Our results indicate that prolonged hyperoxia leads to lung injury, PH, RVH, and disrupted PA cGMP signaling. Furthermore, 24 hours of hyperoxia causes RVH and disrupted PA cGMP signaling that persists for 13 days. Sildenafil reduced RVH and restored vascular cGMP signaling but did not attenuate lung injury. Thus, hyperoxia can rapidly disrupt PA cGMP signaling in vivo with sustained effects, and concurrent sildenafil therapy can be protective.

Sirtuin 3 deficiency does not augment hypoxia-induced pulmonary hypertension.

Alveolar hypoxia elicits increases in mitochondrial reactive oxygen species (ROS) signaling in pulmonary arterial (PA) smooth muscle cells (PASMCs), triggering hypoxic pulmonary vasoconstriction. Mice deficient in sirtuin (Sirt) 3, a nicotinamide adenine dinucleotide-dependent mitochondrial deacetylase, demonstrate enhanced left ventricular hypertrophy after aortic banding, whereas cells from these mice reportedly exhibit augmented hypoxia-induced ROS signaling and hypoxia-inducible factor (HIF)-1 activation. We therefore tested whether deletion of Sirt3 would augment hypoxia-induced ROS signaling in PASMCs, thereby exacerbating the development of pulmonary hypertension (PH) and right ventricular hypertrophy. In PASMCs from Sirt3 knockout (Sirt3(-/-)) mice in the C57BL/6 background, we observed that acute hypoxia (1.5% O2; 30 min)-induced changes in ROS signaling, detected using targeted redox-sensitive, ratiometric fluorescent protein sensors (roGFP) in the mitochondrial matrix, intermembrane space, and the cytosol, were indistinguishable from Sirt3(+/+) cells. Acute hypoxia-induced cytosolic calcium signaling in Sirt3(-/-) PASMCs was also indistinguishable from Sirt3(+/+) cells. During sustained hypoxia (1.5% O2; 16 h), Sirt3 deletion augmented mitochondrial matrix oxidant stress, but this did not correspond to an augmentation of intermembrane space or cytosolic oxidant signaling. Sirt3 deletion did not affect HIF-1α stabilization under normoxia, nor did it augment HIF-1α stabilization during sustained hypoxia (1.5% O2; 4 h). Sirt3(-/-) mice housed in chronic hypoxia (10% O2; 30 d) developed PH, PA wall remodeling, and right ventricular hypertrophy that was indistinguishable from Sirt3(+/+) littermates. Thus, Sirt3 deletion does not augment hypoxia-induced ROS signaling or its consequences in the cytosol of PASMCs, or the development of PH. These findings suggest that Sirt3 responses may be cell type specific, or restricted to certain genetic backgrounds.

Capacity Building in Remote Facilitation of Newborn Resuscitation.

The past decade has been notable for widespread dissemination of newborn resuscitation training in low-resource settings through simplified training programs including Helping Babies Breathe. Since 2020, implementation efforts have been impacted by restrictions on travel and in-person gatherings with the SARS-CoV-2 pandemic, prompting the development of alternative methods of training. While previous studies have demonstrated feasibility of remote neonatal resuscitation training, this perspective paper covers common barriers identified and key lessons learned developing a cadre of remote facilitators. Challenges of remote facilitation include mastering videoconferencing platforms, establishing personal connections, and providing effective oversight of skills practice. Training sessions can be used to support facilitators in acquiring comfort and competency in harnessing videoconferencing platforms for effective facilitation. Optimization of approaches and investment in capacity building of remote facilitators are imperative for effective implementation of remote neonatal resuscitation training.