Search Results (15)

Background/Objectives: To identify the risk factors and clinical outcomes of persistent pulmonary hypertension of the newborn (PPHN) in very low birth weight (VLBW) infants in a resource-limited setting. Methods: We conducted a 1:4 matched case–control study in a Thai neonatal unit between 2014 and 2023. Neonates born at a gestational age (GA) < 32 weeks and with a birth weight (BW) < 1500 g were included. Neonates who died in the delivery room or had major congenital anomalies were excluded. Matching was based on GA, BW, year of birth, and endotracheal intubation at birth. Conditional logistic regression analysis was performed. Results: Over the 10-year study period, the incidence of PPHN among VLBW neonates was 4.6% (31/667). After matching, there were 31 cases and 124 controls. In univariable analysis, PPHN was significantly associated with lower 1 min and 5 min Apgar scores; however, no significant association remained in multivariable analysis. PPHN was significantly associated with composite adverse outcomes—including mortality and major morbidities (adjusted odds ratio [aOR] = 7.51, 95% confidence interval [CI]: 2.41–23.40), mortality alone (aOR = 2.88, 95% CI: 1.06–7.63), major morbidities (aOR = 2.99; 95% CI: 1.29–6.95), and severe neurological injury (aOR = 4.44, 95% CI: 1.56–12.59). Daily hospital costs were also higher in PPHN cases, with an average increase of 97.1 USD. Conclusions: In VLBW infants, PPHN was associated with a lower Apgar score and surfactant administration. PPHN was significantly linked to adverse outcomes, particularly mortality, major morbidities, and severe neurological injury. Full article

Background/Objectives: Persistent pulmonary hypertension of the newborn (PPHN) is characterized by increased pulmonary vascular resistance, resulting in severe hypoxemia. This study determined the factors associated with increased risk of mortality and survival rate in infants with PPHN. Methods: This retrospective study was conducted between 2010 and 2023. The risk factors for mortality were assessed by Cox’s proportional hazard models, and the Kaplan–Meier survival curve was used to analyze the survival rates. Results: This study included 233 neonates with PPHN. Gestational age (GA) less than 28 weeks (adjusted hazard ratio [AHR] = 5.46, 95% confidence interval [CI]: 2.25–13.24, p < 0.001), Small for gestational age (SGA) (AHR = 2.93, 95% confidence interval [CI]: 1.24–6.92, p = 0.026), acute kidney injury (AKI) (AHR = 2.48, 95% CI: 1.27–4.84, p = 0.01), pneumothorax (AHR = 3.03, 95% confidence interval [CI]: 1.48–6.21, p = 0.003), vasoactive-inotropic score (VIS) at 24 h of age (AHR = 1.0026, 95% confidence interval [CI]: 1.0004–1.005, p = 0.026), and score for neonatal acute physiology II (SNAP-II) ≥ 43 (AHR = 4.03, 95% CI: 1.66–9.77, p = 0.005) were associated with an increased risk of mortality. The overall survival rate was 82.4%; it rose from 63.8% to 87.1% after inhaled nitric oxide (iNO) and extracorporeal membrane oxygenation (ECMO) were introduced (p < 0.001). The cumulative survival rates at the end of the 30 days were 62.1% (95% CI: 49.0–78.7) in the Pre-iNO era and 87.5% (95% CI: 82.7–92.6) in the Post-iNO/ECMO era, respectively (p < 0.001). Conclusions: GA less than 28 weeks, SGA, AKI, pneumothorax, high VIS and SNAP-II scores were associated with mortality in infants with PPHN. The improvement in the survival rate was related to the provision of advanced care, including iNO and ECMO therapy. Full article

PPHN is a common cause of neonatal respiratory failure and is still a serious condition that is associated with high mortality. Objectives: To analyze the clinical characteristics and outcomes of SARS-CoV-2 infection in neonates with PPHN to identify neonatal cases at risk to develop severe illness. Methods: For this systematic review, we adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and searched Medline, Embase, CINAHL, and PubMed for studies on the development of COVID-19 in neonates with PPHN, published from 1 December 2019 to 29 February 2024, with an English language restriction. Results: Of the 2406 papers that were identified, 21 articles were included in the systematic review. Studies involving thirty-six neonates with PPHN and infected with SARS-CoV-2 were analyzed (twenty-nine survived, six died, and one is still hospitalized). The main causes of PPHN in neonates who had COVID-19 were neonatal respiratory distress syndrome (NRDS) (41.7%), meconium-stained amniotic fluid (MSAF) (16.7%), preterm premature rupture of membranes (PPROM) (11.1%), hypoxic ischemic encephalopathy (HIE) (5.5%), pneumonia (5.5%), and idiopathic (2.8%). Most of those neonates were male (33.3%), belonged to Indian ethnicity (50%), and were delivered via caesarean section (44.4%). COVID-19 in cases with PPHN commonly occurred in neonates born with a pregnancy range from 32 to <37 weeks (moderate to late preterm) (36.1%). The maternal severity of COVID-19 was reported to be severe in three cases only (8.3%); however, SARS-CoV-2 infection in neonates with PPHN was either severe (44.4%) or critical (22.2%). Most of these neonates experienced acute respiratory distress syndrome (ARDS) (58.3%). Early and late multisystem inflammatory syndrome in neonates (MIS-N) were reported in 50% and 11.1%, respectively. A high proportion of neonates were admitted to the intensive care unit (ICU) (58.3%) or needed mechanical ventilation (MV) (47.2%). Neonates with concurrent PPHN and SARS-CoV-2 infection who died had worse severity of COVID-19 [i.e., severity of COVID-19 was critical in 10% (neonates with PPHN who survived group) vs. 83.3% (neonates with PPHN who died group); p = 0.026]. Neonates with PPHN and COVID-19 had a higher relative risk of death if they received more antibiotics (RR 4.14, 95% CI 0.64–6.88) and if their COVID-19 was defined as critical (RR 2.84, 95% CI 0.86–9.39). Male neonates with PPHN and COVID-19 (RR 2.60, 95% CI 0.30–1.17) and those requiring prolonged invasive positive pressure ventilation (RR 2.22, 95% CI 0.64–7.73) also showed an increased relative risk for death. Conclusions: COVID-19 in neonates with PPHN is challenging and may be associated with increased mortality, severity, ICU admission, ARDS, MIS-N, and MV usage. The results should be interpreted with caution owing to the small number of studies and substantial heterogeneity and indicate a need for future research in this area. Due to its benefits, testing for SARS-CoV-2 should be encouraged for newborns with symptoms consistent with COVID-19, especially in neonates with a history of SARS-CoV-2 exposure. Effective protection measures should be implemented during delivery and post-delivery care as necessary. Full article

Background: Neonatal hypoxic respiratory failure (HRF) secondary to PPHN (persistent pulmonary hypertension of the newborn) is an uncommon but life-threatening complication. Despite advances in therapeutic interventions, there are neonates who may require ECMO (extracorporeal membrane oxygenation), which improves survival. In establishing the capability of ECMO in transport in New South Wales, significant variation in referral thresholds and management of PPHN in referring hospitals has been noted. Aim: To review cases referred to the Newborn and paediatric Emergency Transport Service (NETS) for consideration of ECMO due to HRF in neonates. The aetiology of HRF, the number of retrievals and their short-term outcomes were reported. Methods: A retrospective audit of referrals to NETS (January 2019 to December 2022) of infants aged <28 days with HRF for ECMO. Patient demographics, management, advice at the time of call and the outcome are described. Results: The mean weight was 3511 g, mean gestation was 37.1 weeks and 69% of the patients were male. The main diagnoses were MAS/PPHN (50%), and there was variation in inotropes and ventilation strategies at the time of the referral. Six (25%) of the fifteen babies who were transported by NETS to paediatric intensive care were placed on ECMO at the referring hospital. A further six babies were stabilised at the referral centre following NETS co-ordinated specialist advice and did not require retrieval or ECMO. All the babies who received ECMO and survived had normal early development (<6 months) with normal head US or MRI imaging. Conclusions: Optimising ventilation and inotrope management can eliminate the need for ECMO prior to or following retrieval. Early referral for the consideration of ECMO and a collaborative discussion can assist in optimising conventional therapy, thus eliminating the need for ECMO. Neonates requiring ECMO for HRF have good survival rates with good short-term neurological outcomes. Full article

Hypoxic-ischemic encephalopathy (HIE) is the leading cause of mortality among term newborns globally. Infants born through meconium-stained amniotic fluid are at risk of developing meconium aspiration syndrome (MAS) and HIE. Simultaneous occurrence of MAS and HIE is a perilous combination for newborns due to the risk of persistent pulmonary hypertension of the newborn (PPHN). Moreover, therapeutic hypothermia (TH), which is the current standard of care for the management of HIE, may increase pulmonary vascular resistance (PVR) and worsen PPHN. Infants with MAS and HIE require close cardiorespiratory and hemodynamic monitoring for PPHN. Therapeutic strategies, including oxygen supplementation, ventilation, use of surfactant, inhaled nitric oxide and other pulmonary vasodilators, and systemic vasopressors, play a critical role in the management of PPHN in MAS, HIE, and TH. While TH reduces death or disability in infants with HIE, infants with MAS and HIE undergoing TH need close hemodynamic monitoring for PPHN. Full article

There are potential benefits and risks to the infant with higher and lower oxygen saturation (SpO₂) targets, and the ideal range for infants with pulmonary hypertension (PH) remains unknown. Targeting high SpO₂ can promote pulmonary vasodilation but cause oxygen toxicity. Targeting lower SpO₂ may increase pulmonary vascular resistance, especially in the presence of acidosis and hypothermia. We will conduct a randomized pilot trial to compare two ranges of target preductal SpO₂ in late-preterm and term infants with hypoxic respiratory failure (HRF) and acute pulmonary hypertension (aPH) of the newborn. We will assess the reliability of a newly created HRF/PH score that could be used in larger trials. We will assess trial feasibility and obtain preliminary estimates of outcomes. Our primary hypothesis is that in neonates with PH and HRF, targeting preductal SpO₂ of 95–99% (intervention) will result in lower pulmonary vascular resistance and pulmonary arterial pressures, and lower the need for pulmonary vasodilators (inhaled nitric oxide—iNO, milrinone and sildenafil) compared to targeting SpO₂ at 91–95% (standard). We also speculate that a higher SpO₂ target can potentially induce oxidative stress and decrease response to iNO (oxygenation and pulmonary vasodilation) for those patients that still require iNO in this range. We present considerations in planning this trial as well as some of the details of the protocol design (Clinicaltrials.gov (NCT04938167)). Full article

Resuscitation with 21% O₂ may not achieve target oxygenation in preterm infants and in neonates with persistent pulmonary hypertension of the newborn (PPHN). Inhaled nitric oxide (iNO) at birth can reduce pulmonary vascular resistance (PVR) and improve PaO₂. We studied the effect of iNO on oxygenation and changes in PVR in preterm lambs with and without PPHN during resuscitation and stabilization at birth. Preterm lambs with and without PPHN (induced by antenatal ductal ligation) were delivered at 134 d gestation (term is 147–150 d). Lambs without PPHN were ventilated with 21% O₂, titrated O₂ to maintain target oxygenation or 21% O₂ + iNO (20 ppm) at birth for 30 min. Preterm lambs with PPHN were ventilated with 50% O₂, titrated O₂ or 50% O₂ + iNO. Resuscitation with 21% O₂ in preterm lambs and 50%O₂ in PPHN lambs did not achieve target oxygenation. Inhaled NO significantly decreased PVR in all lambs and increased PaO₂ in preterm lambs ventilated with 21% O₂ similar to that achieved by titrated O₂ (41 ± 9% at 30 min). Inhaled NO increased PaO₂ to 45 ± 13, 45 ± 20 and 76 ± 11 mmHg with 50% O₂, titrated O₂ up to 100% and 50% O₂ + iNO, respectively, in PPHN lambs. We concluded that iNO at birth reduces PVR and FiO₂ required to achieve target PaO₂. Full article

Infants born through meconium-stained amniotic fluid (MSAF) are 100 times more likely than infants born through clear amniotic fluid to develop respiratory distress in the neonatal period. Meconium aspiration syndrome (MAS) is a common cause of respiratory distress in term and post-mature neonates. MAS is defined as respiratory distress accompanied by a supplemental oxygen requirement in an infant born with MSAF, in the absence of any other identified etiology to explain the symptoms. Therapy for MAS is supportive, and should be tailored to each infant’s specific pathophysiology. In cases of MAS with severe persistent pulmonary hypertension of the newborn (PPHN), patients may remain hypoxic despite aggressive ventilation, and in these cases surfactant, inhaled nitric oxide (iNO) and extracorporeal membrane oxygenation (ECMO) can be life-saving. Long-term prognosis for MAS is more related to severity of initial hypoxemia and possible neurological insult than to the pulmonary pathology. Full article

Persistent pulmonary hypertension of the newborn (PPHN) is a syndrome of high pulmonary vascular resistance (PVR) commonly seen all over the world in the immediate newborn period. Several case reports from India have recently described severe pulmonary hypertension among infants in the postneonatal period. These cases typically present with respiratory distress in 1–6-month-old infants, breastfed by mothers on a polished rice-based diet. Predisposing factors include respiratory tract infection such as acute laryngotracheobronchitis with change in voice, leading to pulmonary hypertension, right atrial and ventricular dilation, pulmonary edema and hepatomegaly. Mortality is high without specific therapy. Respiratory support, pulmonary vasodilator therapy, inotropes, diuretics and thiamine infusion have improved the outcome of these infants. This review outlines four typical patients with thiamine-responsive acute pulmonary hypertension of early infancy (TRAPHEI) due to thiamine deficiency and discusses pathophysiology, clinical features, diagnostic criteria and therapeutic options. Full article

Oxygen is a pulmonary vasodilator and plays an important role in mediating circulatory transition from fetal to postnatal period. Oxygen tension (PO₂) in the alveolus (PAO₂) and pulmonary artery (PaO₂) are the main factors that influence hypoxic pulmonary vasoconstriction (HPV). Inability to achieve adequate pulmonary vasodilation at birth leads to persistent pulmonary hypertension of the newborn (PPHN). Supplemental oxygen therapy is the mainstay of PPHN management. However, optimal monitoring and targeting of oxygenation to achieve low pulmonary vascular resistance (PVR) and optimizing oxygen delivery to vital organs remains unknown. Noninvasive pulse oximetry measures peripheral saturations (SpO₂) and a target range of 91–95% are recommended during acute PPHN management. However, for a given SpO₂, there is wide variability in arterial PaO₂, especially with variations in hemoglobin type (HbF or HbA due to transfusions), pH and body temperature. This review evaluates the role of alveolar, preductal, postductal, mixed venous PO₂, and SpO₂ in the management of PPHN. Translational and clinical studies suggest maintaining a PaO₂ of 50–80 mmHg decreases PVR and augments pulmonary vasodilator management. Nevertheless, there are no randomized clinical trials evaluating outcomes in PPHN targeting SpO₂ or PO₂. Also, most critically ill patients have umbilical arterial catheters and postductal PaO₂ may not be an accurate assessment of oxygen delivery to vital organs or factors influencing HPV. The mixed venous oxygen tension from umbilical venous catheter blood gas may assess pulmonary arterial PO₂ and potentially predict HPV. It is crucial to conduct randomized controlled studies with different PO₂/SpO₂ target ranges for the management of PPHN and compare outcomes. Full article

Background: The aim was to evaluate the relationship between the direction of the patent ductus arteriosus (PDA) shunt and the pre- and postductal gradient for arterial blood gas (ABG) parameters in a lamb model of meconium aspiration syndrome (MAS) with persistent pulmonary hypertension of the newborn (PPHN). Methods: PPHN was induced by intermittent umbilical cord occlusion and the aspiration of meconium through the tracheal tube. After delivery, 13 lambs were ventilated and simultaneous 129 pairs of pre- and postductal ABG were drawn (right carotid and umbilical artery, respectively) while recording the PDA and the carotid and pulmonary blood flow. Results: Meconium aspiration resulted in hypoxemia. The bidirectional ductal shunt had a lower postductal partial arterial oxygen tension ([PaO₂] with lower PaO₂/FiO₂ ratio—97 ± 36 vs. 130 ± 65 mmHg) and left pulmonary flow (81 ± 52 vs. 133 ± 82 mL/kg/min). However, 56% of the samples with a bidirectional shunt had a pre- and postductal saturation gradient of < 3%. Conclusions: The presence of a bidirectional ductal shunt is associated with hypoxemia and low pulmonary blood flow. The absence of a pre- and postductal saturation difference is frequently observed with bidirectional right-to-left shunting through the PDA, and does not exclude a diagnosis of PPHN in this model. Full article

Objectives: The indication of inhaled nitric oxide (iNO) used in preterm infants has not been well defined. Neonates with refractory hypoxemia may benefit from the pulmonary vasodilatory effects of iNO. The aim of this study was to investigate the off-label use of iNO as a rescue therapy. Methods: Between January 2010 and December 2017, all neonates who received iNO as a rescue therapy from a tertiary-level medical center were enrolled, and those who were not diagnosed with persistent pulmonary hypertension of newborn (PPHN) were defined as having received off-label use of iNO. The controls were 636 neonates with severe respiratory failure requiring high-frequency oscillatory ventilation but no iNO. Results: A total of 206 neonates who received iNO as a rescue therapy were identified, and 84 (40.8%) had off-label use. The median (interquartile) gestational age was 30.5 (26.3–37.0) weeks. Neonates receiving iNO had significantly more severe respiratory failure and a higher oxygenation index than the controls (p < 0.001). Respiratory distress syndrome and secondary pulmonary hypertension after severe bronchopulmonary dysplasia (BPD) were the most common causes of the off-label iNO prescription. Of the 84 neonates with off-label use of iNO, 53 (63.1%) had initial improvement in oxygenation, but 44 (52.4%) eventually died. The overall mortality rate was 41.7% (86/206). After multivariate logistic regression, extremely preterm (odds ratio [OR] 5.51; p < 0.001), presence of pulmonary hemorrhage (OR 2.51; p = 0.036) and severe hypotension (OR 2.78; p = 0.008) were the independent risk factors for final mortality. Conclusions: iNO is applicable to be an off-label rescue therapy for premature neonates with refractory hypoxemia due to severe pulmonary hypertension and bronchopulmonary dysplasia. Full article

Persistent pulmonary hypertension of the newborn (PPHN) is a syndrome of failed circulatory adaptation at birth due to delay or impairment in the normal fall in pulmonary vascular resistance (PVR) that occurs following birth. The fetus is in a state of physiological pulmonary hypertension. In utero, the fetus receives oxygenated blood from the placenta through the umbilical vein. At birth, following initiation of respiration, there is a sudden precipitous fall in the PVR and an increase of systemic vascular resistance (SVR) due to the removal of the placenta from circulation. There is dramatic increase in pulmonary blood flow with a decrease in, and later reversal of shunts at the foramen ovale and ductus arteriosus. The failure of this normal physiological pulmonary transition leads to the syndrome of PPHN. PPHN presents with varying degrees of hypoxemic respiratory failure. Survival of infants with PPHN has significantly improved with the use of gentle ventilation, surfactant and inhaled nitric oxide (iNO). PPHN is associated with significant mortality and morbidity among survivors. Newer agents that target different enzymatic pathways in the vascular smooth muscle are in different stages of development and testing. Further research using these agents is likely to further reduce morbidity and mortality associated with PPHN. Full article

Pulmonary arterial hypertension (PAH) management has been transformed in recent times with the advent of cheap and effective diagnostic tools and therapy. Sildenafil, a phosphodiesterase-V inhibitor, has been at the centre of this treatment, and its success in treating PAH has led to its widespread uptake in adult and paediatric pulmonary hypertension (PH), as a first line treatment choice. This might apply to persistent pulmonary hypertension of the newborn (PPHN) or bronchopulmonary dysplasia, as well as to more complex diseases, such as idiopathic pulmonary hypertension. Although recent data regarding long-term mortality and the repeal of Food and Drug Administration (FDA) approval has complicated the issue, Sildenafil continues to be the major treatment option for paediatric PH for patients in a variety of contexts, and this does not seem likely to change in the foreseeable future. In this review, we provide a summary of pulmonary hypertension in infants and children and the use of Sildenafil for such diseases. Full article

Background: Persistent pulmonary hypertension of the newborn (PPHN) causes significant morbidity and mortality in neonates. n-3 Poly-unsaturated fatty acids have vasodilatory properties in the perinatal lung. We studied the circulatory effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in fetal sheep and in fetal pulmonary arterial rings. Methods: At 128 days of gestation, catheters were placed surgically in fetal systemic and pulmonary circulation, and a Doppler probe around the left pulmonary artery (LPA). Pulmonary arterial pressure and LPA flow were measured while infusing EPA or DHA for 120 min to the fetus, to compute pulmonary vascular resistance (PVR). The dose effects of EPA or DHA were studied in vascular rings pre-constricted with serotonin. Rings treated with EPA were separated into three groups: E+ (intact endothelium), E− (endothelium stripped) and LNA E+ (pretreatment of E+ rings with l-nitro-arginine). Results: EPA, but not DHA, induced a significant and prolonged 25% drop in PVR (n = 8, p < 0.001). Incubation of vascular rings with EPA (100 µM) caused a maximum relaxation of 60% in the E+ (n = 6), whereas vessel tone did not change in the E− (n = 6, p < 0.001). The vascular effects of EPA were significantly decreased in LNA E+ (n = 6). Incubation with DHA resulted in only a mild relaxation at the highest concentration of DHA (300 µM) compared to E+. Conclusions: EPA induces a sustained pulmonary vasodilatation in fetal lambs. This effect is endothelium- and dose-dependent and involves nitric oxide (NO) production. We speculate that EPA supplementation may improve pulmonary circulation in clinical conditions with PPHN. Full article