An Asian multicenter retrospective study on persistent pulmonary hypertension of the newborn: incidence, etiology, diagnosis, treatment and outcome

Comparison of Different Treatments of Persistent Pulmonary Hypertension of the Newborn: A Systematic Review and Network Meta-Analysis

OBJECTIVES

Persistent pulmonary hypertension of the newborn (PPHN) is a life-threatening disease. Despite being considered the gold standard treatment scheme, inhaled nitric oxide (iNO) is not readily available in settings with limited resources. Therefore, in recent years, research on related drugs is being actively pursued. Herein, we aimed to use random-effects network meta-analysis to evaluate the efficacy and associated mortality of different PPHN therapies.

DATA SOURCES

We electronically searched the PubMed, Embase, and Cochrane Library for data up to January 27, 2023.

STUDY SELECTION

Randomized controlled trials involving neonates with PPHN assessing efficacy and mortality of various treatments.

DATA EXTRACTION

Details of study population, treatments, and outcomes were extracted.

DATA SYNTHESIS

Direct pairwise comparisons and a network meta-analysis was performed under random effects. The ranking probability was further assessed based on the surface under the cumulative ranking curve (SUCRA). We analyzed 23 randomized clinical trials involving 902 newborns with PPHN. Sixteen different treatment strategies were compared with each other and conventional therapy (CON). A median concentration of 10-20 parts per million (ppm) iNO (MNO) coupled with sildenafil orally administered at a dose of 1-3 mg/kg/dose every 6-8 hours (OSID) demonstrated the best efficacy (MNO + OSID vs. CON: odds ratio [OR] = 27.53, 95% CI, 2.36-321.75; SUCRA = 0.818, ranking first; moderate quality). OSID combined with milrinone administered IV also performed well in terms of efficacy (OSID + milrinone vs. CON: OR = 25.13, 95% CI = 1.67-377.78; SUCRA = 0.811, ranking second; low quality) and mortality reduction (CON vs. OSID + milrinone: OR = 25.13, 95% CI = 1.67-377.78; SUCRA = 0.786, ranking last; low quality).

CONCLUSIONS

MNO + OSID is the most effective PPHN treatment. If iNO is not available, OSID + milrinone is preferred.

Use of Vasopressin as Rescue Therapy in Refractory Hypoxia and Refractory Systemic Hypotension in Term Neonates with Severe Persistent Pulmonary Hypertension-A Prospective Observational Study

OBJECTIVE

 Persistent pulmonary hypertension of the newborn (PPHN) is a serious cardiorespiratory problem. PPHN is frequently associated with refractory hypoxia and hypotension, and optimal management has the potential to improve important clinical outcomes including mortality. The primary objective is to evaluate the efficacy and safety of rescue vasopressin (VP) therapy in the management of severe (refractory) hypoxia and refractory systemic hypotension in term neonates with severe PPHN.

STUDY DESIGN

 Neonates with refractory hypoxia and refractory hypotension due to severe PPHN needing VP were prospectively enrolled in the study. Refractory hypoxia was defined as oxygenation index (OI) ≥ 25 for at least 4 hours after the commencement of high-frequency oscillatory ventilation and nitric oxide at 20 ppm. Refractory hypotension was defined as mean blood pressure lesser than mean gestational age lasting for more than 15 minutes in spite of dopamine infusion at 10 µg/kg/min, adrenaline infusion at 0.3 µg/kg/min, and noradrenaline infusion at 0.1 µg/kg/min.

RESULTS

 Thirty-two neonates with PPHN were recruited. The baseline OI (mean ± standard deviation [SD]) before starting VP was 33.43 ± 16.54 which started decreasing significantly between 1 and 6 hours after the commencement of VP (p < 0.05). The mean blood pressure also increased concomitantly with a significant effect seen by 1 hour (p < 0.05). The vasoactive infusion score before the commencement of VP was mean 46.07 (SD = 25.72) and started decreasing after 12 to 24 hours of commencement of VP (p < 0.05). Lactate levels (mean ± SD) before starting VP were 7.8 ± 8.6 mmol/L and started decreasing between 6 and 12 hours (p < 0.05). Two neonates died due to refractory hypoxia and refractory hypotension (overall mortality 6.2%) CONCLUSION:  Rescue VP therapy is a useful adjunct in the management of neonates with severe PPHN with refractory hypoxia and/or refractory hypotension. Improvement in oxygenation and hemodynamics with the use of VP results in reduced mortality.

KEY POINTS

· Rescue vasopressin is a useful adjunct in the management of neonates with severe PPHN.. · Vasopressin helps reduce OI.. · Vasopressin reduces the vasoactive inotrope score..

Etiology, Diagnosis and Management of Persistent Pulmonary Hypertension of the Newborn in Resource-limited Settings

Persistent Pulmonary Hypertension of the Newborn (PPHN) is more common in Low and middle income countries (LMICs) due to high incidence of sepsis, perinatal asphyxia and meconium aspiration syndrome. Presence of hypoxic respiratory faillure and greater than 5% difference in preductal and post ductal saturation increases clinical sucipision for PPHN. The availability of Inhaled nitric oxide and extracorporaeal membrane oxygenation is limited but pulmonary vasodilators such as sildenafil are readily available in most LMICs.

Risk factors for death caused by early onset sepsis in neonates: a retrospective cohort study

OBJECTIVE

To evaluate the association between traditional laboratory findings and death, and to find risk factors for death in infants with early onset sepsis (EOS).

STUDY DESIGN

This was a single-center, case-control, retrospective trial conducted between January 2020 and August 2021. Infants with EOS were enrolled and divided into two groups based on outcome before hospital discharge: non-survivors (Mortality group) and survivors (Survival group).

RESULTS

Out of 556 eligible neonates, there were 38 (6.8%) deaths. After univariate analysis and ROC curve analysis, there were a total of 12 values with significant differences (p < 0.05) between two groups, which included birth weight (BW), weight on admission, gestational age, age on admission, mode of delivery, septic shock, heart failure, respiratory failure, pulmonary hypertension, hypothermia, serum lactic acid, and aspartate aminotransferase (AST). Moreover, after multivariate analysis performed for those 12 values, the binary logistic regression analysis showed that taking death as a reference, the BW (OR = 1.00, 95% CI[1.001, 1.002], p < 0.001), PPHN (OR = 2.60, 95% CI[1.04, 6.52], p > 0.001), septic shock (OR = 6.15, 95% CI [2.52, 15.00], p < 0.001), heart failure (OR = 6.22, 95% CI[0.90, 43.05], p > 0.001), serum lactic acid (OR = 0.82, 95%CI[0.75, 0.90], p < 0.001), and AST (OR = 1.00, 95% CI[0.99, 1.00], p > 0.001) could be regarded as risk factors for death with 94.0% correct predictions.

CONCLUSIONS

The factors affecting the prognosis of EOS in neonates were BW, PPHN, septic shock, heart failure, serum lactic acid, and AST. Timely correction of these modifiable risk factors for death may decrease the mortality of EOS in neonates.

Short-term study of atrial shunt and improvement of functional mitral regurgitation

BACKGROUND

This study used an atrial septal shunt to compare the treatment progress and prognosis for patients with heart failure (HF) who have different ejection fractions.

METHODS

Twenty HF patients with pulmonary hypertension, who required atrial septal shunt therapy, were included in this study. The patients underwent surgery between December 2012 and December 2020. They were divided into two groups based on their ejection fraction: a group with reduced ejection fraction (HFrEF) and a group with preserved ejection fraction(HFpEF) + mid-range ejection fraction (HfmrEF). Echocardiography was utilized to evaluate parameters such as left ventricular dimension (LVD), left ventricular ejection fraction (LVEF), and left ventricular end-diastolic volume (LVEDV). Hemodynamic parameters were measured using cardiac catheterization. The patient's cardiac function was assessed using the six-minute walking test (6MWT), KCCQ score, NYHA classification, and the degree of functional mitral regurgitation (FMR). Followed-up visits were conducted at 1, 3, and 6 months, and any adverse effects were recorded.

RESULTS

The LVEF values were consistently higher in the HFpEF+HFmrEF group than HFrEF group at all periods (P < 0.05). Differences in LVD were observed between the two groups before the surgery. Statistically, significant differences were found at the preoperative stage, 1 month, and 3 months (P < 0.05, respectively). However, the LVEDV showed a significant difference between the two groups only at 3 months (P = 0.049). Notably, there were notable variations in LAPm, LAPs, and the pressure gradient between the LA-RA gradient at baeline, after implantation, and during the 6 months follow-up (all P < 0.05).

CONCLUSION

Following treatment, the HFpEF+HFmrEF group exhibited more significant improvements in echocardiographic and cardiac catheterization indices than the HFrEF group. However, there was no statistically significant difference between the two groups regarding the 6MWT and KCCQ scores. It is important to note that the findings of this study still require further investigation in a large sample size of patients.

Management of neonatal pulmonary hypertension-a survey of neonatal intensive care units in India

BACKGROUND

Persistent pulmonary hypertension of the newborn (PPHN) is a common neonatal condition associated with significant morbidity and mortality. First-line diagnostic and treatment options such as echocardiography and inhaled nitric oxide (iNO) are not routinely available in resource limited settings and alternative treatment modalities need to be utilized. This study was conducted to assess current diagnostic and management strategies used for PPHN in Indian neonatal intensive care units (NICUs).

METHODS

A questionnaire in multiple choice question format was sent to practising neonatologists in India via an online survey tool between July to August 2021. Information pertaining to demographic data, diagnostic criteria and management strategies of PPHN was requested. The responses were collated and information processed.

RESULTS

There were 118 respondent NICUs (response rate 74%). The majority of neonatal units (65%) admitted an average of 1-3 patients of PPHN per month. Targeted neonatal echocardiography (TnECHO) was practised in 80% of the units. Most common management strategies being followed were pulmonary vasodilators (88.1%), inotropes (85.6%), conventional ventilation (68.6%) and high frequency ventilation (59.3%). The most preferred pulmonary vasodilator was sildenafil (79%) and inotropic agent was milrinone (32%). Only 25% of respondents reported use of iNO. None of the participating units used extracorporeal membrane oxygenation.

CONCLUSION

We found wide variability in management practices of PPHN across Indian NICUs. Non-selective pulmonary vasodilators are more widely used than iNO. There is an urgent need for structured TnECHO training programs and evidence based national guidelines for standardized management of PPHN as per availability of resources in India. Additional research on low cost alternative therapies to iNO in Indian settings might be helpful.

A nomogram prediction model for early death in patients with persistent pulmonary hypertension of the newborn

Background

Persistent pulmonary hypertension of the newborn (PPHN) is a major lethal disorder in neonates that leads to an extremely high mortality rate. Thus, the early identification of adverse outcomes in PPHN is critical for clinical practice. This research attempted to develop a nomogram prediction system for assessing the mortality of newborns with PPHN.

Methods

Two hundred and three newborns with PPHN diagnosed from January 2015 to March 2022 were involved in the study. The clinical features of these newborns and pregnancy details were compared between newborns in the survival and lethal groups. Univariable and multivariate analyses were established in sequence to demonstrate the essential risk factors. The nomogram prediction model was built.

Results

A total of 203 newborns were included in the analysis. 136 (67.0%) newborns represented the hospital survival group. Plasma pH value (OR = 0.606, p = 0.000, 95% CI 0.45715-0.80315), septicemia (OR = 3.544, p = 0.000, 95% CI 1.85160-6.78300), and abnormal pregnancy history (OR = 3.331, p = 0.008, 95% CI 1.37550-8.06680) were identified as independent risk factors for neonatal death in newborns associated with PPHN. Finally, the nomogram predictive model was established based on multivariate analysis results, indicating the efficacies of prediction and calibration.

Conclusion

This study generated an applicable risk score formula using the plasma pH value, septicemia, and abnormal pregnancy history to recognize neonatal death in newborns with PPHN, presenting a sufficient predictive value and calibration.

Controversies in neonatology: The efficacy of inhaled nitric oxide in preterm infants with persistent pulmonary hypertension

Introduction: There is limited and conflicting information in literature regarding use of inhaled nitric oxide (iNO) in preterm infants. In this study we examined the characteristics of preterm infants with persistent pulmonary hypertension (PHT) who responded and did not respond to iNO therapy . Material and Method: We retrospectively reviewed data of infants

Possible association between a polymorphism of EPAS1 gene and persistent pulmonary hypertension of the newborn: a case-control study

OBJECTIVE

To explore possible genes related to the development of persistent pulmonary hypertension of the newborn (PPHN).

METHODS

The authors identified 285 single nucleotide polymorphisms (SNPs) of 11 candidate genes (BMPR2, EPAS1, PDE3A, VEGFA, ENG, NOTCH3, SOD3, CPS1, ABCA3, ACVRL1, and SMAD9), using an Illumina Asian Screening Array-24 v1.0 BeadChip Array. The FastLmmC and R package was used for statistical analyses. The chi-square test and Cochrane-Armitage trend test were used to compare the allele and genotype frequencies between the groups and to test the genetic models, respectively.

RESULTS

A total of 45 PPHN infants and 294 control subjects were analyzed. The most common cause of PPHN was meconium aspiration syndrome. Among the 285 SNPs, 17 SNPs from 6 candidate genes (BMPR2, EPAS1, PDE3A, VEGFA, ENG, and NOTCH3) were significantly associated with PPHN (P < 0.05). After using the Bonferroni correction (P < 0.00018), only the rs17034984 SNP located in intron 1 of the EPAS1 gene remained significantly different between the PPHN and control subjects (P = 0.00014). The frequency of the TC/TT genotype of rs17034984 in the gene with the dominant model was significant in the patients with PPHN (OR = 5.38, 95% CI: 2.15-13.49). The T allele frequency of rs17034984 in the gene showed a significant difference compared with the control subjects (OR = 4.89, 95% CI: 2.03-11.82).

CONCLUSIONS

The present study suggests that the rs17034984 variant of EPAS1 gene is associated with PPHN.

[Early risk factors for death in neonates with persistent pulmonary hypertension of the newborn treated with inhaled nitric oxide]

OBJECTIVES

To evaluate the early risk factors for death in neonates with persistent pulmonary hypertension of the newborn (PPHN) treated with inhaled nitric oxide (iNO).

METHODS

A retrospective analysis was performed on 105 infants with PPHN (gestational age ≥34 weeks and age <7 days on admission) who received iNO treatment in the Department of Neonatology, Children's Hospital of Nanjing Medical University, from July 2017 to March 2021. Related general information and clinical data were collected. According to the clinical outcome at discharge, the infants were divided into a survival group with 79 infants and a death group with 26 infants. Univariate and multivariate Cox regression analyses were used to evaluate the risk factors for death in infants with PPHN treated with iNO. The receiver operating characteristic (ROC) curve was used to calculate the cut-off values of the factors in predicting the death risk.

RESULTS

A total of 105 infants with PPHN treated with iNO were included, among whom 26 died (26/105, 24.8%). The multivariate Cox regression analysis showed that no early response to iNO (HR=8.500, 95%CI: 3.024-23.887, P<0.001), 1-minute Apgar score ≤3 points (HR=10.094, 95%CI: 2.577-39.534, P=0.001), a low value of minimum PaO2/FiO2 within 12 hours after admission (HR=0.067, 95%CI: 0.009-0.481, P=0.007), and a low value of minimum pH within 12 hours after admission (HR=0.049, 95%CI: 0.004-0.545, P=0.014) were independent risk factors for death. The ROC curve analysis showed that the lowest PaO2/FiO2 value within 12 hours after admission had an area under the ROC curve of 0.783 in predicting death risk, with a sensitivity of 84.6% and a specificity of 73.4% at the cut-off value of 50, and the lowest pH value within 12 hours after admission had an area under the ROC curve of 0.746, with a sensitivity of 76.9% and a specificity of 65.8% at the cut-off value of 7.2.

CONCLUSIONS

Infants with PPHN requiring iNO treatment tend to have a high mortality rate. No early response to iNO, 1-minute Apgar score ≤3 points, the lowest PaO2/FiO2 value <50 within 12 hours after admission, and the lowest pH value <7.2 within 12 hours after admission are the early risk factors for death in such infants. Monitoring and evaluation of the above indicators will help to identify high-risk infants in the early stage.

Risk Factors and Outcomes of Acute Kidney Injury in Neonates with Persistent Pulmonary Hypertension of the Newborn

Objective

To identify the incidence of and risk factors for acute kidney injury (AKI) in neonates with persistent pulmonary hypertension of the newborn (PPHN) and to evaluate its association with neonatal outcomes.

Method

A total of 78 newborns with confirmed PPHN admitted to the neonatal intensive care unit of a university hospital between 2016 and 2020 were retrospectively analyzed. AKI was defined according to the modified neonatal Kidney Disease: Improving Global Outcomes criteria.

Results

Of 78 PPHN infants, AKI was found in 29.5% (23/78). Multivariate analysis indicated that male sex (OR 3.43 95% CI 1.03-11.48, p=0.04) and severe PPHN (OR 5.67 95% CI 1.55-20.68, p<0.01) were independently associated with increased risk for AKI. Infants with AKI had significantly higher mortality rate than infants without AKI (43.5% vs. 9.1%, p<0.01). Mortality rates in stage 1, stage 2 and stage 3 AKI were similar (36.4%, 57.1%, and 40%, respectively, p=0.68). Among survivors, AKI infants had significantly longer mechanical ventilation and lenght of stay than infants without AKI.

Conclusion

In infants with PPHN, AKI is a common complication and is associated with increased mortality, and longer mechanical ventilation and lenght of stay. Careful monitoring of kidney function in infants with PPHN, especially in males and those who had severe PPHN can help to improve patient outcomes.

Application of B-Type Natriuretic Peptide in Neonatal Diseases

Numerous congenital or secondary diseases, including, heart disease, respiratory disease, sepsis and many others, can lead to neonatal death. B-type natriuretic peptide (BNP) is a peptide hormone secreted by ventricular cells following an increase in ventricular wall tension. BNP functions to promote vasodilation, diuresis, and sodium release to regulate blood pressure. BNP is a sensitive index reflecting ventricular function, which may aid the diagnosis and monitoring of various neonatal diseases. In neonates, there is currently no consensus on a reference BNP level, as the plasma BNP concentration of healthy newborns varies with age, peaks in the first week after birth, and then gradually decreased to a stable level. In disease states, the correlation between the plasma BNP concentration and the results of echocardiography is good, which is of great significance in the screening, monitoring, and prognosis evaluation of neonatal cardiovascular diseases, including congenital heart disease, patent ductus arteriosus, etcetera. It also facilitates the judgment of the efficacy of treatment and perioperative management. Moreover, the monitoring of plasma BNP concentration provides guidance for the diagnosis, evaluation, and treatment selection of certain neonatal respiratory diseases and neonatal sepsis. This review summarizes the normal BNP values and discusses the application value of BNP in relation to physiological and pathological aspects in neonates.

Clinical Efficacy and Safety of Different Doses of Sildenafil in the Treatment of Persistent Pulmonary Hypertension of the Newborn: A Network Meta-analysis

Objective: To evaluate the efficacy and safety of different doses of sildenafil for persistent pulmonary hypertension of the newborn (PPHN) with Bayesian random effects network meta-analysis.

Methods: We searched Chinese and English databases for randomized controlled trials (RCTs) concerning sildenafil in newborns with persistent pulmonary hypertension from 1998 to December 2020.

Results: Twenty-two RCTs including over 2131 patients were included. Sildenafil was administered by nasal feeding at 0.3–2 mg/kg every 4–6 h. The network meta-analysis revealed that 1.5 mg/kg of sildenafil led to a significant decrease in pulmonary artery systolic pressure (PASP) compared with 0.3 and 0.6 mg/kg (p < 0.05); 1.5 mg/kg was better than 0.3, 0.5, and 1.0 mg/kg at increasing the partial pressure of oxygen (PaO₂) (p < 0.05); 1.5 mg/kg was better than 0.5, 0.6 and 1.0 mg/kg at reducing the partial pressure of carbon dioxide (PaCO₂) (p < 0.05); and 1.2 mg/kg was better than 0.3, 0.5 and 1.0 mg/kg at increasing the arterial oxygen saturation (SaO₂) (p < 0.05). The surface under the cumulative ranking analysis (SUCRA) results showed that 1.5 mg/kg had the best effect in reducing PASP (SUCRA = 92.0%, moderate certainty evidence) and PaCO₂ (91.1%) and increasing PaO₂ (SUCRA = 79.3%, moderate certainty evidence), 2.0 mg/kg had the best effect in increasing SaO₂ (SUCRA = 88.6%, moderate certainty evidence) and total effective rate (SUCRA = 93.5%, low certainty of evidence)). No severe adverse effects were observed with the different doses of sildenafil.

Conclusion: Different doses of sildenafil can significantly improve PPHN, and 1.5 mg/kg of sildenafil has better clinical efficacy and does not increase the probability of adverse reactions.

Postnatal causes and severity of persistent pulmonary Hypertension of Newborn

Background & Objective:

Persistent pulmonary hypertension of the newborn (PPHN) is described as severe respiratory failure along with hypoxaemia. PPHN is known to be linked with high morbidity and mortality around the world. This study was planned to determine the postnatal causes and assess the severity of persistent pulmonary hypertension of newborn in babies presenting to the Children’s Hospital, Multan.

Methods:

This observational study was conducted at the Department of Paediatric Cardiology, The Children Hospital &Institute of Child Health, Multan, Pakistan from July to December 2019. A total of 122 confirmed cases of PPHN admitted having gestational age above 34 weeks were enrolled. Demographic data of the newborns was recorded along with maternal medical history, pregnancy status and postnatal causes of PPHN. Severity of PPHN was also recorded.

Results:

Out of a total of 122 cases of PPHN, 81 (66.3%) were male. Majority, 78 (64.0%) had gestational age above 37 weeks. Mode of delivery as cesarean section was noted in 70 (57.4%). Meconium aspiration syndrome 52 (42.6%), birth asphyxia 48 (39.3%), respiratory distress syndrome 23 (18.8%) and sepsis 33 (27.0%) were found to be the commonest causes of PPHN. Severe PPHN was found to be the most frequent, noted among 63 (51.6%) while Moderate PPHN was observed in 40 (32.8%) and Mild PPHN in 19 (15.6%). Morality was noted among 26 (21.3%) of cases.

Conclusion:

Meconium aspiration syndrome, birth asphyxia and respiratory distress syndrome were the commonest postnatal causes of PPHN. Severe PPHN was found to be the most frequent form of PPHN.

Pulmonary hypertension in late onset neonatal sepsis using functional echocardiography: a prospective study

PURPOSE

Pulmonary hypertension (PH) in the newborn period is associated with significant morbidity and mortality. Sepsis has been identified as an independent risk factor for PH in newborns. Data on the proportion and severity of PH in association with neonatal sepsis are scarce. This study was aimed to measure the pulmonary artery systolic pressure (PASP) in neonates with late onset sepsis (LOS) and to estimate the proportion of PH in neonatal sepsis using functional echocardiography (FnECHO).

METHODS

This prospective observational study was conducted at a tertiary neonatal intensive care unit (NICU). All neonates admitted in the NICU with suspected LOS underwent FnECHO within 6 hours of onset of clinical signs and PASP was recorded. Pulmonary hypertension was defined as PASP of > 35 mmHg. PASP of neonates with positive culture results (proven LOS) was compared with that of gestational age-matched stable controls without sepsis.

RESULTS

Thirty three neonates with proven LOS were analysed (study group). Sixteen neonates (49%) in the study group had PH. Mean PASP of the study group was significantly higher than that of the control group (35.3 ± 10.13 mmHg and 12.58 ± 3.92 mmHg, respectively; P < 0.0001). None of the neonates in the control group had PH.

CONCLUSION

Pulmonary artery pressure was higher in neonates with late onset neonatal sepsis as compared to that of stable babies without sepsis. Pulmonary hypertension was seen in nearly half of term as well as preterm neonates with late onset sepsis.

Utility of Low Dose Vasopressin for Persistent Pulmonary Hypertension of Newborn with Catecholamine Refractory Shock

OBJECTIVE

To evaluate the effect of low dose vasopressin on the hemodynamics of neonates with persistent pulmonary hypertension and catecholamine refractory shock.

METHODS

This retrospective study was conducted in a level III NICU of a tertiary care teaching hospital, south India. Eighteen neonates with hypoxemic respiratory failure due to persistent pulmonary hypertension of newborn with catecholamine refractory shock were studied. Neonates were managed for hypotension with conventional inotropic support with the additional use of low dose vasopressin (LDV). Effect of vasopressin on oxygenation index (OI), blood pressure, duration of inotropic usage and survival was evaluated.

RESULTS

Mean OI was 38.2 ± 4.9, and mean blood pressure was 30.7 ± 5.3 mmHg before the start of vasopressin. Initiation of LDV (0.0003 ± 0.0001 IU/kg/min) for a median duration 36.4 ± 17.9 h was followed by a reduction in OI (p < 0.001), control of hypotension (p < 0.001), reduction in lactic acidosis (p < 0.001) and decline in inotropic support.

CONCLUSIONS

In resource-restricted settings, LDV may be useful as a rescue therapy for persistent pulmonary hypertension of newborn with catecholamine refractory shock.

Survival and associated risk factors for mortality among infants with persistent pulmonary hypertension of the newborn in Malaysia

OBJECTIVE

This study aims to determine the immediate outcome of persistent pulmonary hypertension of the newborn (PPHN) and risk factors for mortality in the era of inhaled nitric oxide (iNO).

STUDY DESIGN

This observational cross-sectional study includes 195 confirmed PPHN with a gestational age of ≥34 weeks without congenital heart disease. Multivariable logistic regression was used to identify risk factors for mortality.

RESULTS

The mortality rate was 16.4%, with the highest mortality with pulmonary hypoplasia. Of 195, 65% received iNO; 18% were iNO non-responders with the majority having pulmonary hypoplasia. Independent risk factors for mortality were the presence of reversal of flow at the descending aorta, pulmonary hypoplasia, APGAR scores ≤ 5 at 5 min, and idiopathic PPHN with an adjusted odds ratio of 15.9, 7.5, 6.7, and 6.4, respectively.

CONCLUSIONS

Despite the usage of iNO, mortality due to PPHN remains high and is related to etiology and cardiac function.

Asphyxia and Neonatal Respiratory Distress Syndrome Are Independent Predictors of the Non-response to Inhaled Nitric Oxide in the Newborns With PPHN

Aim: Not all the neonates respond with improvement in oxygenation following inhaled nitric oxide treatment (iNO) treatment. The aim of this study was to assess the independent risk factors associated with non-response to iNO during the 2 weeks of postnatal treatment in neonates diagnosed with persistent pulmonary hypertension (PPHN). Materials and Methods: This retrospective cohort study included all newborns with PPHN who received iNO treatment for more than 24 h. Demographic, obstetric, perinatal data and clinical complications were extracted from the hospitalization records. Subjects were divided into two groups according to their response to iNO inspiration during the first 24 h of iNO treatment. No response was defined as an increase in SpO₂ < 5% or the inability to sustain saturation levels in the first 24 h of iNO treatment. For descriptive statistics, χ² and t-test analysis were used to compare categorical and continuous variables between the two groups. To evaluate independent risk factors of non-responsiveness to iNO treatment, binary logistic regression analysis were performed. Results: A total of 75 newborns were included in the study. Sixty-two cases were in the responders group, and 13 cases were in the non-responders group. Univariate analysis showed that asphyxia, neonatal respiratory distress syndrome (NRDS), pulmonary surfactant administration, meconium aspiration syndrome (MAS), the severity of pulmonary hypertension (PH), and high-frequency oscillatory ventilation (HFOV) therapy were the high-risk factors affecting the response to iNO treatment in the newborns with PPHN. The binary logistic regression analysis indicated that asphyxia and NRDS incidence were independent predictors of non-responsiveness to iNO treatment [asphyxia: OR 4.193, 95% CI 1.104-15.927, P = 0.035; NRDS: OR 0.154, 95% CI 0.036-0.647, P = 0.011]. The patients in the non-responders group had shorter iNO inspiration followed by MV duration, supplemental oxygen and hospital stay, and higher mortality. There were no significant differences in IVH, PVL, and BPD between two groups. Conclusion: In the newborns with PPHN, asphyxia and NRDS resulted as the independent risk factors of non-responsiveness to iNO therapy. Asphyxia in the newborns with PPHN is detrimental to the response to iNO treatment, while NRDS is beneficial.

Oral drugs used to treat persistent pulmonary hypertension of the newborn

Introduction:Persistent Pulmonary Hypertension of the Newborn (PPHN) is a life-threatening neonatal condition, mostly treated with inhaled nitric oxide (iNO), intravenous prostaglandins, oral bosentan, sildenafil and tadalafil. However, the utility of non-oral agents is limited in PPHN for their side effects and inconvenient deliveries. Therefore, oral agents such as bosentan, sildenafil and tadalafil are becoming appealing for their satisfactory efficacy, easy mode of administration and acceptable side effects. Areas covered: We conducted a comprehensive search on Pubmed, Scopus, Web of Sciences concerning the use of bosentan, sildenafil and tadalafil to treat PPHN and summarized their efficacy, safety and pharmacokinetics. Expert opinion: Current randomized controlled trials (RCTs) have demonstrated the favorable responses and tolerable side effects of bosentan and sildenafil. Nevertheless, those RCTs are small and only one study has described the pharmacokinetics of sildenafil in neonates. Accordingly, bosentan, sildenafil and tadalafil remain off-label in clinical use. More well-designed RCTs with large samples and long-term follow-up and pharmacometrics studies are needed to demonstrate the efficacy, safety and pharmacokinetics of bosentan, sildenafil and tadalafil in PPHN.

Hérnia diafragmática Congênita: aspectos clínico-hospitalares em um hospital de referência materno-infantil na região Amazônica

RESUMO O objetivo deste estudo é analisar o perfil clínico-hospitalar de neonatos com o diagnóstico de hérnia diafragmática congênita (HDC), no período de 2008 a 2018 em um hospital de referência materno-infantil. Trata-se de um estudo transversal e analítico descritivo, que incluiu principalmente dados de prontuários com os códigos Q79.0, Q79.1, J986, K44 e K44.0 da Classificação Internacional de Doenças (CID-10). Os critérios de exclusão de prontuários foram o diagnóstico de outros tipos de hérnia diafragmática, sem o aspecto congênito; a internação em unidades que não fossem UTI Neonatal; e a idade no ato de internação igual ou superior a 29 dias. Analisou-se um total de 25.602 prontuários, dos quais 14 corresponderam a HDC. O acometimento por gênero foi de 71,43% masculino (10 casos) e 28,57% feminino (4), com 21,34% das localizações de HDC tipo Bochdalek à direita (3) e 78,57% à esquerda (11). Todos os neonatos deste estudo passaram por ventilação mecânica invasiva (VMI) 9,21 ± 5,55 dias. A cirurgia foi indicada em 11 casos (78,57%), com vias de acesso por toracotomia em 4 (36,36%) e por laparotomia subcostal em 7 (63,64%), todos com uso de dreno torácico homolateral ao hemitórax. O tempo total de internação foi de 19,42 ± 15,36 dias. Observou-se a evolução de alta melhorada em oito pacientes (57,14%) e o óbito de seis (42,86%), com idade de 6,19 ± 4,79 dias, sem referência de acompanhamento do desenvolvimento neuropsicomotor posteriormente. Ocorreram baixas incidências de casos por ano, e o gênero de acometimento, as malformações associadas e o tempo de VMI foram semelhantes a outras populações no mundo.

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.

Surfactant lavage for neonatal meconium aspiration syndrome-An updated meta-analysis

BACKGROUND

Surfactant lavage seems to have a good application prospect both in experimental models and patients with meconium aspiration syndrome (MAS). Data regarding the effect of surfactant lavage on pulmonary complications of MAS are conflicting. In view of these uncertainties, an updated meta-analysis including the latest literatures is performed.

METHODS

A search was conducted by two investigators involved in this research in PubMed, Embase, and Cochrane databases for studies in English and other languages, in Wanfang, VIP, and Cnki databases for Chinese studies (all last launched on December 18, 2018). Ultimately, we identified 11 original studies, including the surfactant lavage group (n = 189) and the control group (n = 204). Odds ratio and weighted mean difference were calculated using a random effects or fixed effects model, depending on the data type and heterogeneity of the included studies.

RESULTS

The comparison of effectiveness on MAS: (1) With respect to oxygen index at 48 hours stage and 72 hours stage, data showed significant difference between surfactant lavage/control groups (we/ighted mean difference [WMD] = -3.37, 95% confidence interval [CI], -5.68 ~ -1.06; p = 0.004 and 95% CI, -5.03 ~ -2.37; p < 0.00001). (2) With respect to days on mechanical ventilation, the analysis showed that there was significant difference between surfactant lavage group and control group (WMD = -1.12, 95% CI, -1.40 ~ -0.84; p < 0.00001). (3) Regarding the need for extracorporeal membrane oxygenation, days of oxygen therapy, and hospital stay, no significant differences were found. The comparison of possible complications of MAS: (1) Regarding pneumothorax, the analysis showed there was significant difference between surfactant lavage and control groups (odds ratio [OR] = 0.46, 95% CI, 0.24 ~ 0.85; p = 0.01). (2) With respect to mortality, persist pulmonary hypertension and pulmonary hemorrhage, the results showed no difference between the two groups.

CONCLUSION

With respect to oxygen index and days on mechanical ventilation, surfactant lavage is significantly effective compared with control group, though didn't eventually shorten days of oxygen therapy and hospital stay. In addition, our meta-analysis showed that surfactant lavage does not increase the risk of complications.

Pulmonary hypertension in paediatrics. A feasible approach to bridge the gap between real world and guidelines

Pulmonary hypertension (PH) is quite infrequent in paediatric age and its most common aetiologies include idiopathic pulmonary arterial hypertension, PH related to congenital heart diseases, bronchopulmonary dysplasia (chronic lung disease), persistence of pulmonary hypertension of the newborn, and congenital diaphragmatic hernia. The developed for adult patients PH classification shows limitations when applied to paediatric subjects, since the underlying causes are markedly different between the two ages. In 2011, the Pulmonary Vascular Research Institute Panama Task Force outlined the first specific paediatric pulmonary hypertensive vascular disease diagnostic classification, including 10 main categories and 109 subcategories, thus testifying PH complex pathophysiology during newborns/children growth and development. The unique, distinctive features of paediatric PH were recognized also during the fifth World Symposium on Pulmonary hypertension in 2013 and then confirmed in the recent 2018 sixth World Symposium. For the sake of uniformity, an attempt to adapt the adult classification to paediatric patients was made. However, all these commendable classifications are very complex and may be not of quick comprehension for clinicians. A clinical simpler and simplified method is now suggested, comprising only five groups: Neonatal, Cardiac, Developmental, Idiopathic, and Syndromic PH. This approach is not aimed at replacing the already existing classifications, but is mainly based on the kind of specialized physician (neonatologist, paediatric cardiologist, paediatrician, pulmonologist, general practitioner) who first faces and looks after the child with suspected PH. What is dramatically known is that paediatric PH is a severe disease which, when untreated or undertreated, may lead to increased morbidity and mortality.

The Off-Label Use of Inhaled Nitric Oxide as a Rescue Therapy in Neonates with Refractory Hypoxemic Respiratory Failure: Therapeutic Response and Risk Factors for Mortality

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.

Risk factor analysis of pneumothorax associated with persistent pulmonary hypertension of the newborn in Thai neonates

Objective: To determine the risk factors and outcomes of persistent pulmonary hypertension of the newborn (PPHN)-associated pneumothorax (PTX).Study design: The medical records of infants diagnosed with PPHN with or without PTX from January 2012 to July 2017 were retrospectively reviewed.Results: Of the 102 included PPHN infants, PTX was found in 32 (31.4%) infants with 43.8% (14/32) mortality. PTX was significantly associated with increased mortality with an odds ratio (OR) of 5.27 (95% confidence interval [CI] 1.96-14.17). Unilateral PTX was more common than bilateral PTX (53.1 versus 46.9%, respectively). Multivariate logistic regression analysis indicated that a 1-minute Apgar score of ≤7 was associated with an increased risk for PTX (adjusted OR = 2.67 [95% CI 1.14-6.25]). In subgroup analysis, each increase of maximum peak inspiratory pressure (PIP) of 1 cmH₂O significantly increased the odds of PTX by 1.46 (95% CI 1.02-2.07), while each 1 mmHg increase in arterial partial pressure of oxygen (P_aO₂) decreased the odds of PTX (adjusted OR = by 0.98 [95% CI 0.97-0.99]).Conclusions: PTX was significantly associated with higher mortality in PPHN infants. Lower Apgar score and increasing PIP in conventional mechanical ventilation were risk factors for PTX. Higher P_aO₂ was associated with a decreased rate of PTX.