Inhaled nitric oxide reduces the need for extracorporeal membrane oxygenation in infants with persistent pulmonary hypertension of the newborn

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.

Research trends and hotspots of exosomes in respiratory diseases

Currently, theoretical studies on exosomes in respiratory diseases have received much attention from many scholars and have made remarkable progress, which has inestimable value and potential in future clinical and scientific research. Unfortunately, no scholar has yet addressed this field's bibliometric analysis and summary. We aim to comprehensively and profoundly study and explore the present situation and highlights of exosome research at the stage of respiratory diseases and to provide meaningful insights for the future development of this field. The WOSCC literature was gathered for the study using bibliometrics, and the data were collected and analyzed using CiteSpace, VOSviewer, Microsoft Excel, and Endnote software. The publication language is "English," and the search strategy is TS = (exosome OR exosomes OR exosomal) AND TS = (respiratory OR lung). The search time is from the beginning of the WOS construction, and the deadline is July 11, 2022, at 22:00 hours. The literature types selected were dissertation, review paper, and online published paper. The analysis includes 2456 publications in 738 journals from 76 countries, 2716 institutions, and 14,568 authors. The field's annual publications have been rising, especially in recent years. China and the US lead research, and prominent universities, including Harvard Medical School, Shanghai Jiao Tong University, and Fudan University, are essential research institutes. Takahiro Ochiya, whose research focuses on exosomes and lung cancer, and Clotilde Théry, a pioneering exosome researcher, are the most cited authors in this field. The key terms include lung cancer, non-small cell lung cancer, mesenchymal stem cells, intercellular communication, exosomal miRNAs, and oncology. Cell biology, biochemistry & biotechnology, and oncology are related fields. The final summary of research hotspots is exosomes and lung cancer, mesenchymal stem cell-derived exosomes and lung inflammation, and miRNAs in exosomes as biomarkers for respiratory illnesses. The present research situation and relevant hotspots of the area were analyzed through bibliometric studies on exosomes in respiratory diseases. The research development in this field has a considerable upside, and the exosome's function in diagnosing, treating, monitoring, and prognosis of respiratory illnesses cannot be taken lightly. Moreover, we believe the research results will bring the gospel to many patients with clinical respiratory diseases shortly.

Nitric oxide: Clinical applications in critically ill patients

Inhaled nitric oxide (iNO) acts as a selective pulmonary vasodilator and it is currently approved by the FDA for the treatment of persistent pulmonary hypertension of the newborn. iNO has been demonstrated to effectively decrease pulmonary artery pressure and improve oxygenation, while decreasing extracorporeal life support use in hypoxic newborns affected by persistent pulmonary hypertension. Also, iNO seems a safe treatment with limited side effects. Despite the promising beneficial effects of NO in the preclinical literature, there is still a lack of high quality evidence for the use of iNO in clinical settings. A variety of clinical applications have been suggested in and out of the critical care environment, aiming to use iNO in respiratory failure and pulmonary hypertension of adults or as a preventative measure of hemolysis-induced vasoconstriction, ischemia/reperfusion injury and as a potential treatment of renal failure associated with cardiopulmonary bypass. In this narrative review we aim to present a comprehensive summary of the potential use of iNO in several clinical conditions with its suggested benefits, including its recent application in the scenario of the COVID-19 pandemic. Randomized controlled trials, meta-analyses, guidelines, observational studies and case-series were reported and the main findings summarized. Furthermore, we will describe the toxicity profile of NO and discuss an innovative proposed strategy to produce iNO. Overall, iNO exhibits a wide range of potential clinical benefits, that certainly warrants further efforts with randomized clinical trials to determine specific therapeutic roles of iNO.

Epidemiologic evaluation of inhaled nitric oxide use among neonates with gestational age less than 35 weeks

BACKGROUND AND OBJECTIVES

The use of inhaled nitric oxide (iNO) in +late preterm and term infants with pulmonary hypertension is Food and Drug Administration (FDA) approved and has improved outcomes and survival. iNO use is not FDA approved for preterm infants and previous studies show no mortality benefit. The objectives were 1) to determine the usage of iNO among preterm neonates <35 weeks before and after the 2010 National Institutes of Health consensus statement and 2) to evaluate characteristics and outcomes among preterm neonates who received iNO.

METHODS

This is a population-based cross-sectional study. Billing and procedure codes were used to determine iNO usage. Data were queried from the National Inpatient Sample from 2004 to 2016. Neonates were included if gestational age was <35 weeks. The epochs were spilt into 2004-2010 (Epoch 1) and 2011-2016 (Epoch 2). Prevalence of iNO use, mortality, bronchopulmonary dysplasia (BPD), intraventricular hemorrhage, length of stay, mechanical ventilation, and cost of hospitalization.

RESULTS

There were 4865 preterm neonates <35 weeks who received iNO. There was a significant increase in iNO use during Epoch 2 (p < 0.001). There was significantly higher use in Epoch 2 among neonates small for gestational age (SGA) 2.3% versus 7.2%, congenital heart disease (CHD) 11.1% versus 18.6%, and BPD 35.2% versus 46.8%. Mortality was significantly lower in Epoch 2 19.8% versus 22.7%.

CONCLUSION

Usage of iNO was higher after the release of the consensus statement. The increased use of iNO among preterm neonates may be targeted at specific high-risk populations such as SGA and CHD neonates. There was lower mortality in Epoch 2; however, the cost was doubled.

Effect of postoperative administration of inhaled nitric oxide combined with high-frequency oscillatory ventilation in infants with acute hypoxemic respiratory failure and pulmonary hypertension after congenital heart surgery: A retrospective cohort study

OBJECTIVE

To evaluate the effect of inhaled nitric oxide (iNO) combined with high-frequency oscillatory ventilation (HFOV) in the treatment of infants with acute hypoxemic respiratory failure (AHRF) and pulmonary hypertension (PH) after congenital heart surgery.

METHODS

A retrospective study was conducted on 63 infants with AHRF and PH after congenital heart surgery in our cardiac intensive care unit (CICU) from January 2020 to March 2021. A total of 24 infants in the A group were treated with HFOV combined with iNO, and 39 infants in the B group were treated with HFOV. Relevant clinical data were collected.

RESULTS

Comparing the two groups, the improvement of the oxygenation index, PaO₂ and PaO₂ /FiO₂ was more obvious for patients in the A group than for those in the B group after intervention (p < .05). Reexamination on the third day after the initiation of HFOV treatment indicated that the systolic pulmonary artery pressure in the A group was significantly lower than that in the B group (p < .05). In addition, the duration of mechanical ventilation and the length of CICU stay in the A group were shorter than those in the B group (p < .05). However, complications between the two groups were not statistically significant. No important adverse effects arose.

CONCLUSIONS

For infants with AHRF and PH after congenital heart surgery, iNO combined with HFOV is superior to HFOV alone to improve oxygenation, decrease pulmonary pressure, and shorten the duration of mechanical ventilation and the length of CICU stay, with no adverse effects.

Neonatal respiratory and cardiac ECMO in Europe

Neonatal extracorporeal membrane oxygenation (ECMO) is a life-saving procedure for critically ill neonates suffering from a potentially reversible disease, causing severe cardiac and/or respiratory failure and refractory to maximal conventional management. Since the 1970s, technology, management, and clinical applications of neonatal ECMO have changed. Pulmonary diseases still represent the principal neonatal diagnosis, with an overall 74% survival rate, and up to one-third of cases are due to congenital diaphragmatic hernia. The overall survival rate in cardiac ECMO is lower, with congenital heart defect representing the main indication. This review provides an overview of the available evidence in the field of neonatal ECMO. We will address the changing epidemiology, basic principles, technologic advances in circuitry, and monitoring, and deliver a current multidisciplinary management framework, focusing on ECMO applications, complications, and long-term morbidities. Lastly, areas for further research will be highlighted.Conclusions: ECMO is a life support with a potential impact on long-term patients' outcomes. In the next years, advances in knowledge, technology, and expertise may push neonatal ECMO boundaries towards more premature and increasingly complex infants, with the final aim to reduce the burden of ECMO-related complications and improve overall patients' outcomes. What is Known: • ECMO is a life-saving option in newborns with refractory respiratory and/or cardiac failure. • The multidisciplinary ECMO management is challenging and may expose neonates to complications with an impact on long-term outcomes. What is New: • Advances in technology and biomaterials will improve neonatal ECMO management and, eventually, the long-term outcome of these complex patients. • Experimental models of artificial placenta and womb technology are under investigation and may provide clinical translation and future research opportunities.

Inhaled pulmonary vasodilators: a narrative review

Pulmonary hypertension (PH) is a severe disease that affects people of all ages. It can occur as an idiopathic disorder at birth or as part of a variety of cardiovascular and pulmonary disorders. Inhaled pulmonary vasodilators (IPV) can reduce pulmonary vascular resistance (PVR) and improve RV function with minimal systemic effects. IPV includes inhaled nitric oxide (iNO), inhaled aerosolized prostacyclin, or analogs, including epoprostenol, iloprost, treprostinil, and other vasodilators. In addition to pulmonary vasodilating effects, IPV can also be used to improve oxygenation, reduce inflammation, and protect cell. Off-label use of IPV is common in daily clinical practice. However, evidence supporting the inhalational administration of these medications is limited, inconclusive, and controversial regarding their safety and efficacy. We conducted a search for relevant papers published up to May 2020 in four databases: PubMed, Google Scholar, EMBASE and Web of Science. This review demonstrates that the clinical using and updated evidence of IPV. iNO is widely used in neonates, pediatrics, and adults with different cardiopulmonary diseases. The limitations of iNO include high cost, flat dose-response, risk of significant rebound PH after withdrawal, and the requirement of complex technology for monitoring. The literature suggests that inhaled aerosolized epoprostenol, iloprost, treprostinil and others such as milrinone and levosimendan may be similar to iNO. More research of IPV is needed to determine acceptable inclusion criteria, long-term outcomes, and management strategies including time, dose, and duration.

Rationale for Use of an FDA-Cleared Delivery System for Administration of Inhaled Nitric Oxide in Patients Undergoing Magnetic Resonance Imaging

Inhaled nitric oxide (iNO) is a pulmonary vasodilator approved for use to improve lung function in neonates >34 weeks' gestational age with hypoxic respiratory failure and pulmonary hypertension. Infants with severe respiratory disease frequently require magnetic resonance imaging (MRI) scans for evaluation of treatment and diagnosis of concurrent disease processes. Until 2015, incompatibility between the standard iNO delivery system components and the magnetic field within the MRI setting required iNO treatment to be interrupted for MRI, which could increase risk of deoxygenation and rebound pulmonary hypertension. In some cases, patients had to forego or delay MRI in order to maintain uninterrupted iNO delivery. The US Food and Drug Administration cleared the first iNO delivery system specifically modified for conditional use with MRI scanners (INOmax DS_IR ^® Plus MRI) in 2015, based on the determination that the MRI-cleared system met the performance standards equivalent to the standard system. The system design and manufacturer risk management activities, as well as the regulatory requirements for clearance and continued use, provide necessary safeguards to ensure that high-risk neonates receive uninterrupted iNO in a safe manner. Anecdotal reports suggest that adoption of the MRI-cleared system may help optimize care for critically ill neonates who require concurrent administration of iNO and MRI scanning. Further research will be necessary to quantify the nature and magnitude of clinical improvements associated with adoption of the MRI iNO delivery system.

Complications and mortality of venovenous extracorporeal membrane oxygenation in the treatment of neonatal respiratory failure: a systematic review and meta-analysis

Background

Extracorporeal membrane oxygenation (ECMO) has been increasingly used for severe neonatal respiratory failure refractory to conventional treatments. To systematically evaluate the complications and mortality of venovenous ECMO (VV ECMO) in the treatment of neonatal respiratory failure, we performed a systematic review and meta-analysis of all the related studies.

Methods

PubMed, Embase, and Cochrane Library were searched. The retrieval period was from the establishment of the database to February 2019. Two investigators independently screened articles according to the inclusion and exclusion criteria. The quality of article was assessed by the Newcastle-Ottawa scale (NOS). The meta-analysis was performed by Stata 15.0 software.

Results

Four observational studies were included, with a total of 347 newborns. VV ECMO was used for neonates with refractory respiratory failure unresponsive to maximal medical therapy. Median ages of the newborns at cannulation were 43.2 h, 23 h, 19 h, and 71 h in the included four studies, respectively. The overall mortality at hospital charge was 12% (5–18%) with a heterogeneity of I² = 73.8% (p = 0.01). Two studies reported mortality during ECMO and after decannulation, with 10% (0.8–19.2%) and 6.1% (2.6–9.6%), respectively. The most common complications associated with VV ECMO were: pneumothorax (20.6%), hypertension (20.4%), cannula dysfunction (20.2%), seizure (14.9%), renal failure requiring hemofiltration (14.7%), infectious complications (10.3%), thrombi (7.4%), intracranial hemorrhage or infarction (6.6%), hemolysis (5.3%), cannula site bleeding (4.4%), gastrointestinal bleeding (3.7%), oxygenator failure (2.8%), other bleeding events (2.8%), brain death (1.9%), and myocardial stun (0.9%).

Conclusion

The overall mortality at discharge of VV ECMO in the treatment of neonatal respiratory failure was 12%. Although complications are frequent, the survival rate during hospitalization is still high. Further larger samples, and higher quality of randomized controlled trials (RCTs) are needed to clarify the efficacy and safety of this technique in the treatment of neonatal respiratory failure.

Variation in the definition of pulmonary hypertension and clinical indications for the use of nitric oxide in neonatal clinical trials

AIM

Pulmonary hypertension (PH) frequently complicates neonatal hypoxaemic respiratory failure, but is inconsistently defined. We aimed to describe the variation among randomised controlled trials (RCTs) of inhaled nitric oxide (iNO), in relation to the definition of PH and/or hypoxaemic respiratory failure used to select patients for trial inclusion.

METHODS

PubMed, Cochrane Library and ClinicalTrials.gov were systematically searched for RCTs of iNO in neonates. Included studies were assessed for clinical and/or echocardiography criteria used to define PH/hypoxaemic respiratory failure.

RESULTS

Thirty-two trials were included in this review, of which 23 enrolled infants ≥34 weeks' gestation. Echocardiographic diagnosis was used in 21 studies, but there was considerable variation in the echocardiographic parameters used to diagnose PH. The most commonly used indices included markers of tricuspid regurgitation and extrapulmonary shunt.

CONCLUSION

There is wide variation in the definition of PH used to select infants for inclusion into RCTs of iNO therapy in neonates. We recommend that an international consensus be reached on which parameters should be used and the thresholds defining severity of disease.

Neonatal respiratory extracorporeal membrane oxygenation and primary diagnosis: trends between two decades

OBJECTIVE

Examine changing neonatal respiratory extracorporeal membrane oxygenation (ECMO) practice trends and outcomes.

STUDY DESIGN

Retrospective cohort study comparing neonatal respiratory ECMO in the 1990 and 2010 decades (1994-1995 and 2014-2015). Patients ≤ 30 days of life, reported to the Extracorporeal Life Support Organization registry, were included.

RESULTS

Four thousand one hundred and twenty-five patients met inclusion criteria. ECMO cases decreased by 33%. The primary ECMO diagnosis changed significantly over time (p < 0.0001). Survival to discharge decreased (76 vs 67%, p < 0.0001) and ECMO duration increased (131 vs 158 h, p < 0.001). Lung recovery was the most common reason to discontinue ECMO although family request for withdrawal and a diagnosis considered "incompatible with life" was increasingly common in the 2010s.

CONCLUSION

Although the use of ECMO for neonatal respiratory diagnoses has decreased over time, its use has increased for patients with more complex diagnoses and ECMO duration is longer. ECMO continues to be an important supportive therapy, improved understanding of which patients would benefit most is needed.

Effect of NO inhalation on ECMO use rate and mortality in infants born at or near term with respiratory failure

BACKGROUND

The molecular studies showed that Nitric oxide (NO) is an essential factor which regulates pulmonary artery tension. However, the conclusions of existing clinical studies were inconsistent.

OBJECTIVE

This meta-analysis is aimed to determine whether the inhalation of NO could improve oxygenation and reduce rate of death and use of extracorporeal membrane oxygenation (ECMO).

METHODS

The strategies used to search PubMed, The Cochrane Central Register of Controlled trials in the Cochrane Library, Embase, Web of science, Clinical Trials Registry, and China Biology Medicine disc, from inception to February, 2018. The primary outcomes were death or use of ECMO, death before hospital discharge, use of ECMO before hospital discharge, change in PaO2 after treatment. We assess the risk of bias in each included study by Cochrane Handbook, and calculated typical estimates of RR, each with its 95% CI, and for continuous outcomes, WMD or a summary estimate for SMD, each with its 95% CI.

RESULTS

Nine randomized controlled trials (RCTs) with a total of 856 participants were included in this meta-analysis. This meta-analysis revealed that the experimental group had significantly lower death or use of ECMO (RR 0.66, 95% CI 0.57-0.77, I = 0%, P < .00001) and lower use of ECMO before hospital discharge (RR 0.89, 95% CI 0.50-0.71, I = 0%, P < .00001) compared to control group. And in the infants without diaphragmatic hernia, experimental group had significantly higher change in PaO2 after treatment (MD 50.40, 95% CI 32.14-68.66, P < .00001). The meta-analysis also showing a tendency to improve in the death before hospital discharge (RR 0.89, 95% CI 0.60-1.31, I = 0%, P = .55) and the change in PaO2 after treatment of the infants with diaphragmatic hernia (MD 6.70, 95% CI -2.32 to 15.72, P < .00001, P = .15), but no difference between experimental group and control group.

CONCLUSION

We found that NO inhalation can improve oxygenation and reduce rate of death and use of ECMO in this meta-analysis. Therefore, we recommend the use of NO inhalation for infants born at or near term with respiratory failure.

The Role of Echocardiography in Neonates and Pediatric Patients on Extracorporeal Membrane Oxygenation

Indications for extracorporeal membrane oxygenation (ECMO) and extracorporeal cardiopulmonary resuscitation (ECPR) are expanding, and echocardiography is a tool of utmost importance to assess safety, effectiveness and readiness for circuit initiation and separation. Echocardiography is key to anticipating complications and improving outcomes. Understanding the patient's as well as the ECMO circuit's anatomy and physiology is crucial prior to any ECMO echocardiographic evaluation. It is also vital to acknowledge that the utility of echocardiography in ECMO patients is not limited to the evaluation of cardiac function, and that clinical decisions should not be made exclusively upon echocardiographic findings. Though echocardiography has specific indications and applications, it also has limitations, characterized as: prior to and during cannulation, throughout the ECMO run, upon separation and after separation from the circuit. The use of specific and consistent echocardiographic protocols for patients on ECMO is recommended.

Current trends in neonatal ECMO

Extracorporeal membrane oxygenation (ECMO) is a life-saving therapy for patients with respiratory and cardiac failure refractory to maximal medical management. The extracorporeal life support organization registry is the largest available resource for describing the population and outcomes of patients treated with this therapy. The use of ECMO for neonatal patients is decreasing in proportion to the total annual ECMO runs most likely due to advancements in medical management. Although the overall survival for neonatal ECMO has decreased, this is likely a reflection of the increasingly complex neonatal patients treated with this therapy. Although many patient and mechanical complications are decreasing over time, there remains a high percentage of morbidities and risks associated with ECMO. Continued refinements in management strategies are important to improving overall patient outcomes.

The Fragility Index in a Cohort of Pediatric Randomized Controlled Trials

Data suggest inadequacy of common statistical techniques for reporting outcomes in clinical trials. The Fragility Index can measure how many events the statistical significance hinges on, and may facilitate better interpretation of trial results. This study aimed to assess the Fragility Index in pediatric randomized controlled trials (RCTs) with statistically significant findings published in high-quality medical journals. A Fragility Index was calculated on included trials with dichotomous positive outcomes. Analysis of the relationship between trial characteristics and the Fragility Index was performed. Of the 429 abstracts screened, 17 met the inclusion criteria and underwent analysis. The median Fragility Index was 7 with an interquartile range of 2-11. In 41% of the studies, the number of patients lost to follow-up or withdrawn prior to analysis was equal to or greater than the Fragility Index. There was no correlation between the RCT sample size and the Fragility Index (r = 0.249, p = 0.335) nor the event group size and the Fragility Index (r = 0.250, p = 0.334). There was a strong negative correlation between the original p-value and the Fragility Index (r = -0.700, p = 0.002). The Fragility Index is a calculated metric that may assist in applying clinical relevance to statistically significant outcomes in pediatric randomized controlled trials with dichotomous outcomes.

Nitric oxide for respiratory failure in infants born at or near term

BACKGROUND

Nitric oxide (NO) is a major endogenous regulator of vascular tone. Inhaled nitric oxide (iNO) gas has been investigated as treatment for persistent pulmonary hypertension of the newborn.

OBJECTIVES

To determine whether treatment of hypoxaemic term and near-term newborn infants with iNO improves oxygenation and reduces rate of death and use of extracorporeal membrane oxygenation (ECMO), or affects long-term neurodevelopmental outcomes.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 1), MEDLINE via PubMed (1966 to January 2016), Embase (1980 to January 2016) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to January 2016). We searched clinical trials databases, conference proceedings and reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. We contacted the principal investigators of studies published as abstracts to ascertain the necessary information.

SELECTION CRITERIA

Randomised studies of iNO in term and near-term infants with hypoxic respiratory failure, with clinically relevant outcomes, including death, use of ECMO and oxygenation.

DATA COLLECTION AND ANALYSIS

We analysed trial reports to assess methodological quality using the criteria of the Cochrane Neonatal Review Group. We tabulated mortality, oxygenation, short-term clinical outcomes (particularly use of ECMO) and long-term developmental outcomes.

STATISTICS

For categorical outcomes, we calculated typical estimates for risk ratios and risk differences. For continuous variables, we calculated typical estimates for weighted mean differences. We used 95% confidence intervals and assumed a fixed-effect model for meta-analysis.

MAIN RESULTS

We found 17 eligible randomised controlled studies that included term and near-term infants with hypoxia.Ten trials compared iNO versus control (placebo or standard care without iNO) in infants with moderate or severe severity of illness scores (Ninos 1996; Roberts 1996; Wessel 1996; Davidson 1997; Ninos 1997; Mercier 1998; Christou 2000; Clark 2000; INNOVO 2007; Liu 2008). Mercier 1998 compared iNO versus control but allowed back-up treatment with iNO for infants who continued to satisfy the same criteria for severity of illness after two hours. This trial enrolled both preterm and term infants but reported most results separately for the two groups. Ninos 1997 studied only infants with congenital diaphragmatic hernia.One trial compared iNO versus high-frequency ventilation (Kinsella 1997).Six trials enrolled infants with moderate severity of illness scores (oxygenation index (OI) or alveolar-arterial oxygen difference (A-aDO2)) and randomised them to immediate iNO treatment or iNO treatment only after deterioration to more severe criteria (Barefield 1996; Day 1996; Sadiq 1998; Cornfield 1999; Konduri 2004; Gonzalez 2010).Inhaled nitric oxide appears to have improved outcomes in hypoxaemic term and near-term infants by reducing the incidence of the combined endpoint of death or use of ECMO (high-quality evidence). This reduction was due to a reduction in use of ECMO (with number needed to treat for an additional beneficial outcome (NNTB) of 5.3); mortality was not affected. Oxygenation was improved in approximately 50% of infants receiving iNO. The OI was decreased by a (weighted) mean of 15.1 within 30 to 60 minutes after the start of therapy, and partial pressure of arterial oxygen (PaO2) was increased by a mean of 53 mmHg. Whether infants had clear echocardiographic evidence of persistent pulmonary hypertension of the newborn (PPHN) did not appear to affect response to iNO. Outcomes of infants with diaphragmatic hernia were not improved; outcomes were slightly, but not significantly, worse with iNO (moderate-quality evidence).Infants who received iNO at less severe criteria did not have better clinical outcomes than those who were enrolled but received treatment only if their condition deteriorated. Fewer of the babies who received iNO early satisfied late treatment criteria, showing that earlier iNO reduced progression of the disease but did not further decrease mortality nor the need for ECMO (moderate-quality evidence). Incidence of disability, incidence of deafness and infant development scores were all similar between tested survivors who received iNO and those who did not.

AUTHORS' CONCLUSIONS

Inhaled nitric oxide is effective at an initial concentration of 20 ppm for term and near-term infants with hypoxic respiratory failure who do not have a diaphragmatic hernia.

Is Administration of Nitric Oxide During Extracorporeal Membrane Oxygenation Associated With Improved Patient Survival?

OBJECTIVE

To evaluate the outcomes associated with the use of inhaled nitric oxide during extracorporeal membrane oxygenation.

DESIGN

Post hoc analysis of data from an existing administrative national database, Pediatric Health Information system (2004-2014). Multivariable logistic regression models were fitted to study the effect of inhaled nitric oxide during extracorporeal membrane oxygenation on study outcomes.

SETTING

Forty-two children's hospitals across the United States.

PATIENTS

Patients in the age group from 1 day through 18 years admitted to an ICU who received extracorporeal membrane oxygenation during their hospital stay were included.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

In total, 6,419 patients qualified for inclusion. Of these, inhaled nitric oxide was used among 3,629 patients during extracorporeal membrane oxygenation run. Approximately one half of the study patients received inhaled nitric oxide at extracorporeal membrane oxygenation initiation. The proportion of patients receiving inhaled nitric oxide during extracorporeal membrane oxygenation decreased with increasing duration of extracorporeal membrane oxygenation. After adjusting for patient characteristics and center variables, use of inhaled nitric oxide was not associated with any survival benefit. However, higher proportion of patients receiving inhaled nitric oxide were associated with prolonged hospital length of stay and prolonged duration of extracorporeal membrane oxygenation. In adjusted models, the hospital charges were higher in the inhaled nitric oxide group. The median hospital costs among patients receiving inhaled nitric oxide were higher by $39,732 (95% CI, $31,074-48,390) as compared to the patients who did not receive inhaled nitric oxide, after adjusting for patient (including hospital length of stay) and center level variables. As the duration of inhaled nitric oxide therapy increased, proportion of patients with prolonged duration of extracorporeal membrane oxygenation and prolonged hospital length of stay increased.

CONCLUSIONS

This large observational analysis of use of nitric oxide during extracorporeal membrane oxygenation calls into question the benefits of inhaled nitric oxide among patients receiving extracorporeal membrane oxygenation for pulmonary or cardiac failure. Given our inability to determine type of extracorporeal membrane oxygenation and control for severity of illness, these findings should be interpreted as exploratory.

Trends in pediatric pulmonary hypertension-related hospitalizations in the United States from 2000-2009

There are few data on the epidemiology of pulmonary hypertension (PH)-related hospitalizations in children in the United States. Our aim was to determine hospital mortality, length of hospitalization, and hospital charges pertaining to PH-related hospitalizations and also the effects of codiagnoses and comorbidities. A retrospective review of the Kids' Inpatient Database during the years 2000, 2003, 2006, and 2009 was analyzed for patients ≤20 years of age with a diagnosis of PH by ICD-9 (International Classification of Diseases, Ninth Revision) codes, along with associated diagnoses and comorbidities. Descriptive statistics, including Rao-Scott χ(2), ANOVA, and logistic regression models, were utilized on weighted values with survey analysis procedures. The number of PH-related hospital admissions is rising, from an estimated 7,331 (95% confidence interval [CI]: 5,556-9,106) in 2000 to 10,792 (95% CI: 8,568-13,016) in 2009. While infant age and congenital heart disease were most commonly associated with PH-related hospitalizations, they were not associated with mortality. Overall mortality for PH-related hospitalizations was greater than that for hospitalizations not associated with PH, 5.7% versus 0.4% (odds ratio: 16.22 [95% CI: 14.78%-17.8%], P < 0.001), but mortality is decreasing over time. Sepsis, respiratory failure, acute renal failure, hepatic insufficiency, arrhythmias, and the use of extracorporeal membrane oxygenation are associated with mortality. The number of PH-related hospitalizations is increasing in the United States. The demographics of PH in this study are evolving. Despite the increasing prevalence, mortality is improving.

Molecular physiopathogenetic mechanisms and development of new potential therapeutic strategies in persistent pulmonary hypertension of the newborn

Persistent pulmonary hypertension of the newborn (PPHN) is a cyanogenic plurifactorial disorder characterized by failed postnatal drop of pulmonary vascular resistance and maintenance of right-to-left shunt across ductus arteriosus and foramen ovale typical of intrauterine life. The pathogenesis of PPHN is very complex and can result from functional (vasoconstriction) or structural (arteriolar remodeling, reduced pulmonary vessels density) anomalies of pulmonary circulation. Etiopathogenetic factors heterogeneity can strongly condition therapeutical results and prognosis of PPHN that is particularly severe in organic forms that are usually refractory to selective pulmonary vasodilator therapy with inhaled nitric oxide. This paper reports the more recent acquisitions on molecular physiopathogenetic mechanisms underlying functional and structural forms of PPHN and illustrates the bases for adoption of new potential treatment strategies for organic PPHN. These strategies aim to reverse pulmonary vascular remodeling in PPHN with arteriolar smooth muscle hypertrophy and stimulate pulmonary vascular and alveolar growth in PPHN associated with lung hypoplasia.In order to restore lung growth in this severe form of PPHN, attention is focused on the results of studies of mesenchymal stem cells and their therapeutical paracrine effects on bronchopulmonry dysplasia, a chronic neonatal lung disease characterized by arrested vascular and alveolar growth and development of pulmonary hypertension.

Surfactant for meconium aspiration syndrome in term and late preterm infants

BACKGROUND

Surfactant replacement therapy has been proven beneficial in the prevention and treatment of neonatal respiratory distress syndrome (RDS). The deficiency of surfactant or surfactant dysfunction may contribute to respiratory failure in a broader group of disorders, including meconium aspiration syndrome (MAS).

OBJECTIVES

To evaluate the effect of surfactant administration in the treatment of late preterm and term infants with meconium aspiration syndrome.

SEARCH METHODS

We searched The Cochrane Library (Issue 4, 2006), MEDLINE and EMBASE (1985 to December 2006), previous reviews including cross-references, abstracts, conference and symposia proceedings, expert informants, and journal handsearching, without language restrictions. We contacted study authors for additional data.We ran an updated search in November 2014 and searched the following sites for ongoing or recently completed trials: www.clinicaltrials.gov; www.controlled-trials.com; and www.who.int/ictrp.

SELECTION CRITERIA

Randomised controlled trials which evaluated the effect of surfactant administration in late preterm and term infants with meconium aspiration syndrome are included in the analyses.

DATA COLLECTION AND ANALYSIS

We extracted data on clinical outcomes including mortality, treatment with extracorporeal membrane oxygenation (ECMO), pneumothorax, duration of assisted ventilation, duration of supplemental oxygen, intraventricular haemorrhage (any grade and severe IVH), and chronic lung disease. We conducted data analyses in accordance with the standards of the Cochrane Neonatal Review Group.

MAIN RESULTS

Four randomised controlled trials met our inclusion criteria. The meta-analysis of four trials (326 infants) showed no statistically significant effect on mortality [typical risk ratio (RR) 0.98, 95% confidence interval (CI) 0.41 to 2.39; typical risk difference (RD) -0.00, 95% CI -0.05 to 0.05]. There was no heterogeneity for this outcome (I² = 0% for both RR and RD). The risk of requiring extracorporeal membrane oxygenation was significantly reduced in a meta-analysis of two trials (n = 208); [typical RR 0.64, 95% CI 0.46 to 0.91; typical RD -0.17, 95% CI -0.30 to -0.04; number needed to treat for an additional beneficial outcome (NNTB) 6, 95% CI 3 to 25]. There was no heterogeneity for RR (1² = 0%) but moderate heterogeneity for RD (I² = 50%). One trial (n = 40) reported a statistically significant reduction in the length of hospital stay (mean difference -8 days, 95% CI -14 to -3 days; test for heterogeneity not applicable). There were no statistically significant reductions in any other outcomes studied (duration of assisted ventilation, duration of supplemental oxygen, pneumothorax, pulmonary interstitial emphysema, air leaks, chronic lung disease, need for oxygen at discharge or intraventricular haemorrhage).

AUTHORS' CONCLUSIONS

In infants with MAS, surfactant administration may reduce the severity of respiratory illness and decrease the number of infants with progressive respiratory failure requiring support with ECMO. The relative efficacy of surfactant therapy compared to, or in conjunction with, other approaches to treatment including inhaled nitric oxide, liquid ventilation, surfactant lavage and high frequency ventilation remains to be tested.

Adapted ECMO criteria for newborns with persistent pulmonary hypertension after inhaled nitric oxide and/or high-frequency oscillatory ventilation

PURPOSE

Early prediction of extracorporeal membrane oxygenation (ECMO) requirement in term newborns with persistent pulmonary hypertension (PPHN), partially responding to inhaled nitric oxide (iNO) and/or high-frequency oscillatory ventilation (HFOV), based on oxygenation parameters.

METHODS

This was a retrospective cohort study in 53 partial responders from among 133 term newborns with PPHN born between 2002 and 2007. Alveolar-to-arterial oxygen gradient (AaDO₂) values were determined in these 53 partial responders during the initial 72 h of iNO and/or HFOV treatment and compared between newborns who ultimately did (n = 11) and did not (n = 42) need ECMO.

RESULTS

Over 72 h, partial responders not requiring ECMO showed a more profound AaDO₂ decrease than those who needed ECMO (median decline 242.5 mmHg, IQR 144 to 353 mmHg, vs. 35 mmHg, IQR -15 to 123 mmHg; p = 0.0007). A decline of <123 mmHg over 72 h predicted the need for ECMO (sensitivity 82 %, specificity 79 %). At 72 h, AaDO₂ was significantly lower in partial responders without the need for ECMO than in those who did need ECMO (median 369 mmHg, IQR 258 to 478 mmHg, vs. 570 mmHg IQR 455 to 590 mmHg; p = 0.0008). An AaDO₂ >561 mmHg at 72 h predicted the need for ECMO (sensitivity 64 %, specificity 95 %, positive predictive value 78 %).

CONCLUSIONS

In term newborns with PPHN partially responding to iNO and/or HFOV, oxygenation-based prediction of the need for ECMO appears to be possible after 72 h. ECMO centers are encouraged to develop their own prediction model in order to prevent both lung damage and unnecessary ECMO runs.

The use of ECMO for persistent pulmonary hypertension of the newborn: a decade of experience

PURPOSE

Despite improvements in the management of persistent pulmonary hypertension of the newborn (PPHN), a number of infants with inadequate gas exchange are treated with extracorporeal membrane oxygenation (ECMO). The objectives of this study were to use the Extracorporeal Life Support Organization Registry to review the outcomes of neonates with PPHN receiving ECMO, and to identify pre-ECMO variables that may be associated with increased mortality.

MATERIALS AND METHODS

The study is a retrospective analysis of all patients with PPHN supported with ECMO and reported to the Extracorporeal Life Support Organization registry from 2000 to 2010. Prematurity was defined as <37 wk gestation. Univariate analysis was performed using Student's t-test or Fisher's exact test. Variables found to be statistically significant underwent multivariate analysis by logistic regression. Kaplan-Meier survival curves were generated to analyze the relationship between duration of ECMO support and patient survival.

RESULTS

A total of 1569 neonates with PPHN received ECMO support during the study period, at an average age of 3.1 d of life and for a duration of 6.9 d. Survival among neonates with PPHN receiving ECMO support was 81%, and those receiving support for 7, 10, 14, and 21 d survived at rates of 88%, 78%, 55%, and 25%, respectively. By logistic regression, prematurity (P < 0.01), pre-ECMO pH ≤7.2 (P = 0.02), pre-ECMO SaO(2) ≤65% (P = 0.01), and duration of ECMO ≥7 d (P < 0.001) were independent predictors of death in this group. An average of 2.2 complications occurred per patient, with cardiovascular, mechanical, and renal complications being the most common.

CONCLUSIONS

Neonates with PPHN have high survival rates with ECMO support. Prematurity, acidosis, and profound hypoxemia are independently associated with increased mortality. Furthermore, prolonged ECMO support (>7 d) is associated with a higher risk of mortality in this cohort than in patients supported for <1 wk.

Advances in neonatal extracorporeal support: the role of extracorporeal membrane oxygenation and the artificial placenta

This review addresses the history and evolution of neonatal extracorporeal membrane oxygenation (ECMO), with a discussion of the indications, contraindications, modalities, outcomes, and impact of ECMO. Controversies surrounding novel uses of ECMO in neonates, namely ECMO for premature infants and ex utero intrapartum therapy with transition to ECMO, are discussed. The development of an extracorporeal artificial placenta for support of premature infants is presented, including the rationale, research, and challenges. ECMO has had a dramatic effect on the care of critically ill neonates over the past 4 decades, and there is great potential to expand these benefits in the future.

The Effect of Arterial pH on Oxygenation Persists Even in Infants Treated with Inhaled Nitric Oxide

Objective. To validate the empiric observation that pH has an important effect on oxygenation in infants receiving iNO. Study Design. Demographics, ventilator settings, arterial blood gases (ABG), and interventions for up to 96 hours of life were extracted from the charts of 51 infants receiving iNO. Need for ECMO and survival to discharge were noted. Mean blood pressure (MBP) and mean airway pressure (MAP) were recorded. The arterial/alveolar (a/A) ratio was used as the primary outcome. Analysis was by simple linear regression and multiple linear regression analyses and Fisher's exact test. pH responsiveness was arbitrarily defined as a correlation coefficient (CC) of >0.40 with P < 0.05. Results. Mean gestational age was 38.8 weeks and mean birth weight was 3300 g. All patients had clinical diagnosis of PPHN. Clear responsiveness to pH was found in 31/51 infants. MAP and MBP did not correlate with a/A ratio. Three responders had a critical pH > 7.55. Of 11 patients requiring ECMO, only 3 exhibited responsiveness at any time in their course. Three responders required ECMO. Conclusion. This small study suggests that failure or inability to optimize pH may account for observed unresponsiveness to iNO. Maintaining a pH > 7.5 using hyperventilation is not recommended.

Factors associated with survival in pediatric extracorporeal membrane oxygenation--a single-center experience

AIM

We aimed to examine outcomes of extracorporeal membrane oxygenation (ECMO) therapy in the pediatric population and identify pre-ECMO and on-ECMO characteristics that are associated with survival.

METHODS

We retrospectively reviewed the ECMO records at our institution between 1999 and 2008 and selected pediatric patients who were cannulated for respiratory failure or hemodynamic instability resistant to conventional interventions. We recorded details of pre-ECMO clinical characteristics, including blood gas variables and mechanical ventilatory support, and details of ECMO therapy including survival off ECMO and to hospital discharge. Predictors of survival were analyzed using logistic regression modeling and a prediction algorithm was developed.

RESULTS

Of the 445 ECMO runs, data from 58 consecutive patients were analyzed: 57% were successfully decannulated, and 48% survived to discharge from the hospital. The cohort included 32 (55%) female patients, 22 postoperative patients (38%), and 15 (26%) with an immunosuppressive condition, with a median age of 5 years and weight 19.5 kg, The mean duration of pre-ECMO respiratory support was 3 days, in the form of high-frequency oscillatory ventilation (n = 28, 48%) and conventional mechanical ventilation (n = 13, 22%). The median duration (interquartile range) of ECMO support was 142 hours (60, 321) or 5.9 days. Pre-ECMO pH above 7.2 (P < .001) and oxygenation index below 35 (P = .021) were associated with the highest survival rates. Pre-ECMO PaCO(2) and duration of mechanical ventilation were not associated with survival.

CONCLUSIONS

Based on our results, ECMO therapy should be considered early in children with oxygenation index greater than 35 with worsening metabolic status. The restriction of ECMO based on ventilator days alone needs to be revisited in this era of lung protective ventilation.

High prevalence of minor neurologic deficits in a long-term neurodevelopmental follow-up of children with severe persistent pulmonary hypertension of the newborn: a cohort study

BACKGROUND

Persistent pulmonary hypertension of the newborn (PPHN) is a severe condition that determines a profound brain hypoxia. Inhaled nitric oxide was approved for the treatment of PPHN since the end of the 1990s. The debate upon the long term outcome of these children is still open. Our aim was to investigate the incidence of minor long-term neurodevelopmental problems in a cohort of children affected by severe PPHN.

METHODS

All neonates with severe PPHN treated with inhaled nitric oxide in our facility between 01.01.02 and 31.12.07 were seen in a follow up visit and evaluated with a neurodevelopmental scale, according to their age at the time of observation.

RESULTS

in the study period 31 children were diagnosed with severe PPHN. 29 survived. 27 accepted to come for follow-up. Mean age: 41 months (range 12 - 70 months).26% of the evaluated children had some behavioural problems, while 22% had some language disturbances.

CONCLUSIONS

This is the first neurodevelopmental follow-up of neonates with PPHN in which children older than 36 months have been evaluated.There is an unexpected high incidence of minor neurological deficits, mainly regarding the fields of language and behaviour. These deficits seem to be related to the severity of illness rather than to the treatment. Language and behaviour are considered "higher functions" in humans and their integrity can be better defined in older children.

School-age outcomes of newborns treated for persistent pulmonary hypertension

OBJECTIVE

The aim of this study was to describe the school-age outcome of a cohort of children treated with intensive care support for persistent pulmonary hypertension of the newborn (PPHN).

STUDY DESIGN

From 187 term newborns treated for PPHN as neonates, 109 were seen at school age (73% of 150 survivors and 58.2% of the original cohort). Of these 109 term newborns, 77 were treated with inhaled nitric oxide (iNO); of which 12 received extracorporeal membrane oxygenation (ECMO). The remaining 32 received conventional management with no exposure to iNO. Patients were seen at school age (mean 7.1 years). A medical history and physical exam were completed, growth was measured, and chest X-ray and echocardiogram were performed. Psychometric assessments included the Wechsler Scales (Preschool or Child), Vineland Adaptive Behavior Scales, Kaufman Test of Educational Achievement, Children's Category Test, Wisconsin Card Sorting Test and Achenbach Child Behavior Checklist.

RESULT

Medical, neurodevelopmental and social/emotional/behavioral outcome did not differ between children treated with iNO, with or without ECMO, and those managed with no exposure to iNO. Overall, 24% had respiratory problems, 60% had abnormal chest X-rays and 6.4% had some sensorineural hearing loss. The cohort performed at the average level for full scale IQ, adaptive function, academic achievement, higher-order cognition and executive functioning, and social/behavioral/emotional functioning. Overall, 9.2% of the cohort had a full scale IQ less than 70 and 7.4% had an IQ from 70 to 84.

CONCLUSION

The outcome for this cohort of children treated as newborns for PPHN, which included a large group of infants exposed to iNO, was comparable to previous reports of children treated with ECMO or conventionally.

Advances in the diagnosis and management of persistent pulmonary hypertension of the newborn

Rapid evaluation of a neonate who is cyanotic and in respiratory distress is essential for achieving a good outcome. Persistent pulmonary hypertension of the newborn (PPHN) can be a primary cause or a contributing factor to respiratory failure, particularly in neonates born at 34 weeks or more of gestation. PPHN represents a failure of normal postnatal adaptation that occurs at birth in the pulmonary circulation. Rapid advances in therapy in recent years have led to a remarkable decrease in mortality for the affected infants. Infants who survive PPHN are at significant risk for long-term hearing and neurodevelopmental impairments, however. This review focuses on the diagnosis, recent advances in management, and recommendations for the long-term follow-up of infants who have PPHN.

Inhaled nitric oxide in the neonate

Inhaled nitric oxide (iNO) has been used to treat both term and preterm infants with respiratory failure. Term infants with persistent pulmonary hypertension, either as a primary cause or secondary to other disease processes, respond to iNO with improvement in oxygenation indices and a decreased need for extracorporeal membrane oxygenation. Infants with congenital diaphragmatic hernia are the exception to this finding, with little clinical benefit observed with iNO treatment. Although respiratory disease in preterm infants has a component of increased pulmonary vascular resistance, little benefit of iNO administration has been observed in premature infants either early in their course or later as a treatment to prevent the evolution of chronic lung disease.

Medical and financial impact of a neonatal extracorporeal membrane oxygenation referral center in the nitric oxide era

OBJECTIVES

The primary objective of this study was to determine whether widespread use of nitric oxide after Food and Drug Administration approval decreased admissions to a neonatal referral center for extracorporeal membrane oxygenation evaluation. We also sought to determine whether antecedent treatment delayed eventual transfer, resulting in sicker patients, increased mortality, increased extracorporeal membrane oxygenation application, and higher direct costs of care.

METHODS

This was a retrospective cohort study of all of the patients transferred to a neonatal referral center for extracorporeal membrane oxygenation evaluation before (1995-1999) and after (2000-2005) Food and Drug Administration approval of nitric oxide. Patients were divided into "congenital diaphragmatic hernia" and "persistent pulmonary hypertension" (all other diagnoses) for additional analysis.

RESULTS

Admission rates for extracorporeal membrane oxygenation evaluation decreased in the nitric oxide era, and eventual transfer was not delayed. Persistent pulmonary hypertension patients had improved oxygen indexes, a trend toward decreased mortality, decreased extracorporeal membrane oxygenation use, and decreased direct costs. Congenital diaphragmatic hernia patients had unchanged physiologic measurements, mortality, and extracorporeal membrane oxygenation use with increased direct costs of care. As a whole, outcomes for patients transferred for extracorporeal membrane oxygenation evaluation improved, whereas direct costs were unchanged.

CONCLUSIONS

Persistent pulmonary hypertension patients had improved outcomes with decreased costs, whereas congenital diaphragmatic hernia patients had unchanged outcomes with increased costs. Overall, patients admitted to this NICU because of the presence of extracorporeal membrane oxygenation services had improved outcomes without increased costs in the nitric oxide era.

Significance of pulmonary artery size and blood flow as a predictor of outcome in congenital diaphragmatic hernia

AIM

To determine if pulmonary artery size and blood flow have prognostic value in congenital diaphragmatic hernia (CDH).

METHODS

Twenty-eight consecutive left-sided CDH patients treated according to a standard protocol with high frequency oscillatory ventilation (HFOV) + nitric oxide (NO) had right and left pulmonary artery (RPA, LPA) diameters, LPA/RPA diameter (L/R) ratios, and PA blood flows examined by echocardiography (EC) on days 0, 2, and 5 after birth and compared prospectively.

RESULTS

Twenty-two patients (78.6%) survived. Of these, 15 required NO (NO-s), and seven did not (non-NO-s). All six patients that died required NO (NO-d). RPA in the NO-d group was significantly smaller than in the NO-s or non-NO-s groups on day 0 (2.90 +/- 0.41 vs. 3.40 +/- 0.49 or 4.01 +/- 0.43; P < 0.01, respectively). LPA in the NO-d group was significantly smaller than in the non-NO-s on day 0 (2.13 +/- 0.45 vs. 3.39 +/- 0.34; P < 0.01). L/R ratios in NO subjects were significantly smaller (NO-s 0.74 +/- 0.11; NO-d 0.73 +/- 0.11) than in non-NO-s subjects (0.84 +/- 0.03) on day 0 (P < 0.01). PA diameters and L/R ratios did not change significantly from day 0 to day 5 in all three groups. There was LPA flow on day 0 in all non-NO-s subjects, but none in all NO subjects. In the NO-s group, LPA flow was confirmed in 87% (13/15) on day 2 and in 100% on day 5, however, there was no LPA flow from day 0 to day 5 in any of the NO-d group.

CONCLUSION

Our data indicate that PA diameters on day 0 and LPA flow are strongly prognostic in left-sided CDH and L/R ratio would appear to be a simple highly reliable indicator of the necessity for NO therapy.

Management of pulmonary hypertension in congenital diaphragmatic hernia: nitric oxide with prostaglandin-E1 versus nitric oxide alone

AIM

Prostaglandin-E1 (PGE1) is used at most centers for treating pulmonary hypertension (PH) in congenital diaphragmatic hernia (CDH) because it has been regarded as effective. The aim of this study was to investigate the role of PGE1 for treating PH in CDH.

METHODS

We reviewed 49 CDH cases with echocardiography-proven PH. PH was treated with PGE1 and nitric oxide (NO) and high frequency oscillatory ventilation (HFOV) from 1997 to 2001 (PG + NO; n = 19) and with NO and HFOV from 2002 to 2007 (NO; n = 30).

RESULTS

Subject demographics, severity of PH, and presence of other anomalies were not significantly different between the two groups. In the PG + NO group, 12/19 (63.2%) survived (PG + NO-s) and 7/19 (36.8%) died (PG + NO-d). In the NO group, 21/30 (70.0%) survived (NO-s) and 9/30 (30.0%) died (NO-d). Survival rates were not significantly different. In the NO-s group, spontaneous closure of the ductus arteriosus (DA) was significantly earlier compared with the PG + NO-s group (P < 0.01; 4.0 +/- 0.9 vs. 9.5 +/- 2.2 days after birth). DA diameters were significantly larger in groups that died compared with groups that survived (P < 0.01), and PH persisted in groups that died. In the NO-s group, surgery was possible significantly earlier compared with the PG + NO-s group (P < 0.01; 3.75 +/- 0.67 vs. 6.12 +/- 0.78 days after birth). No NO-s case developed a PH crisis even though PGE1 was not used. Hospital stay was significantly shorter in the NO-s group compared with the PG + NO-s group (P < 0.05; 39.9 +/- 19 vs. 53.2 +/- 23 days).

CONCLUSION

Nitric oxide alone would appear to simplify the management of CDH with PH and provide better outcome.

Neonatal pulmonary hypertension treated with inhaled nitric oxide and high-frequency ventilation

Term and near-term infants with pulmonary hypertension are frequently treated with inhaled nitric oxide. This therapy can be delivered with high-frequency ventilation, but there has been limited study of the relative effectiveness of high-frequency jet ventilation and high-frequency oscillatory ventilation.

OBJECTIVE

To compare short-term clinical outcomes of neonates with pulmonary hypertension treated with inhaled nitric oxide plus either high-frequency jet ventilation or high-frequency oscillatory ventilation.

STUDY DESIGN

Study infants met the following criteria: >or=35 weeks gestation, respiratory failure with pulmonary hypertension, no congenital malformations and treatment in the first week of life with inhaled nitric oxide plus either high-frequency jet ventilation (n=22) or high-frequency oscillatory ventilation (n=43). Data were collected from medical records.

RESULT

The jet ventilation and oscillatory ventilation groups were similar in terms of gestational age, but the jet ventilation group had less severe respiratory illness (that is, lower oxygenation index) just prior to initiation of the combination of nitric oxide and high-frequency ventilation. The jet ventilation group spent more hours on inhaled nitric oxide (71.4 versus 40.8; P=0.004) but was less likely to require extracorporeal membrane oxygenation (2(9%) versus 19(44%); P=0.004). No difference was found in the ages at which oxygen and high-frequency ventilation were discontinued.

CONCLUSION

Term and near-term neonates with pulmonary hypertension who require nitric oxide have similar short-term outcomes regardless of whether nitric oxide is delivered by high-frequency jet ventilation or high-frequency oscillatory ventilation.

Airway function in infants treated with inhaled nitric oxide for persistent pulmonary hypertension

RATIONALE

Inhaled nitric oxide (iNO), used for treatment of persistent pulmonary hypertension of newborn (PPHN), is an oxygen free radical with potential for lung injury. Deferring ECMO with iNO in these neonates could potentially have long-term detrimental effects on lung function. We studied respiratory morbidity (defined as occurrence of respiratory infections requiring treatment, episodes of wheezing, and/or need for ongoing medications following discharge) and airway function at 1 year postnatal age in term neonates treated with iNO but not ECMO for PPHN, and compared data from similar infants recruited to the UK ECMO Trial randomized to receive ECMO or conventional management (CM).

METHODS

Maximal expiratory flow at FRC (V(') (maxFRC)) was measured in infants treated with iNO for PPHN (oxygenation index >or=25) at birth.

RESULTS

V(') (maxFRC) was measured in 23 infants and expressed as z-scores, to adjust for sex and body size and compared to data from 71 (46 ECMO, 25 CM) infants studied at a similar age in the ECMO Trial. Respiratory morbidity was low in iNO group. V(') (maxFRC) z-score was lower than predicted in all groups (P < 0.001), with no significant difference between those treated with iNO [mean (SD) z-score: -1.65 (1.2)] and those treated with ECMO [-1.59 (1.2)] or CM [-2.1(1.0)]. Within iNO, ECMO and CM groups; 26%, 37% and 56%, respectively, had V(') (maxFRC) z-scores below normal.

CONCLUSIONS

Respiratory outcome at 1 year in iNO treated neonates with moderately severe PPHN is encouraging, with no apparent increase in respiratory morbidity when compared to the general population. Sub-clinical reductions in airway function are evident at 1 year, suggesting that continuing efforts to minimize lung injury in the neonatal period are warranted to maximize lung health in later life.

Inhaled nitric oxide therapy during the transport of neonates with persistent pulmonary hypertension or severe hypoxic respiratory failure

Our aim was to determine whether starting inhaled nitric oxide (iNO) on critically ill neonates with severe hypoxemic respiratory failure and/or persistent pulmonary hypertension (PPH), at a referring hospital at the start of transport, decreases the need for extracorporeal membrane oxygenation (ECMO), lessens the number of hospital days and improves survival in comparison with those patients who were started on iNO only at the receiving facility. The study was a retrospective review of 94 charts of neonates that had iNO initiated by the transport team at a referring hospital or only at the tertiary neonatal intensive care unit (NICU) of the receiving hospital. Data collected included demographics, mode of transport, total number of hospital days, days on inhaled nitric oxide and ECMO use. Of the 94 patients, 88 were included. Of these, 60 were started on iNO at the referring facility (Field-iNO) and 28 were started at the receiving NICU (CHLA-iNO). All patients survived transport to the receiving NICU. Death rates and ECMO use were similar in both groups. Overall, patients who died were younger and had lower birth weights and Apgar scores. For all surviving patients who did not require ECMO, the length of total hospital stay (median days 22 versus 38, P = 0.018), and the length of the hospital stay at the receiving hospital (median days 18 versus 29, P = 0.006), were significantly shorter for the Field-iNO patients than for the CHLA-iNO patients, respectively. Earlier initiation of iNO may decrease length of hospital stay in surviving neonates with PPH not requiring ECMO.

Surfactant for meconium aspiration syndrome in full term/near term infants

BACKGROUND

Surfactant replacement therapy has been proven beneficial in the prevention and treatment of neonatal respiratory distress syndrome (RDS). The deficiency of surfactant or surfactant dysfunction may contribute to respiratory failure in a broader group of disorders, including meconium aspiration syndrome (MAS).

OBJECTIVES

To evaluate the effect of surfactant administration in the treatment of term/near-term infants with MAS.

SEARCH STRATEGY

Searches were made using The Cochrane Library (Issue 4, 2006), MEDLINE and EMBASE (1985 to December 2006), previous reviews including cross-references, abstracts, conference and symposia proceedings, expert informants, and journal hand searching. No language restrictions were applied. Authors were directly contacted to provide additional data.

SELECTION CRITERIA

Randomised controlled trials which evaluated the effect of surfactant administration in term infants with meconium aspiration syndrome are included in the analyses.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes including mortality, treatment with extracorporeal membrane oxygenation (ECMO), pneumothorax, duration of assisted ventilation, duration of supplemental oxygen, intraventricular haemorrhage (any grade and severe IVH), and chronic lung disease, and were excerpted from the reports of the clinical trails by the review authors. Data analyses were done in accordance with the standards of the Cochrane Neonatal Review Group.

MAIN RESULTS

Four randomised controlled trials met inclusion criteria. The meta-analysis of 4 trials enrolling 326 infants showed no statistically significant effect on mortality (typical relative risk 0.98 (95% CI 0.41, 2.39), typical risk difference 0.00 (95% CI -0.05, 0.05). The risk of requiring extracorporeal membrane oxygenation was significantly reduced in a meta-analysis of two trials (n = 208); (typical relative risk 0.64, 95% CI 0.46, 0.91; typical risk difference -0.17, 95% CI -0.30, -0.04); number needed to treat to benefit 6 (95% CI 3, 25). One trial (n = 40) reported a statistically significant reduction in the length of hospital stay [mean difference - 8 days (95% CI -14, -3 days)]. There were no statistically significant reductions in any other outcomes studied (duration of assisted ventilation, duration of supplemental oxygen, pneumothorax, pulmonary interstitial emphysema, air leaks, chronic lung disease, need for oxygen at discharge or intraventricular haemorrhage).

AUTHORS' CONCLUSIONS

In infants with MAS, surfactant administration may reduce the severity of respiratory illness and decrease the number of infants with progressive respiratory failure requiring support with ECMO. The relative efficacy of surfactant therapy compared to, or in conjunction with, other approaches to treatment including inhaled nitric oxide, liquid ventilation, surfactant lavage and high frequency ventilation remains to be tested.

Nitric oxide for respiratory failure in infants born at or near term

BACKGROUND

Nitric oxide is a major endogenous regulator of vascular tone. Inhaled nitric oxide gas has been investigated as a treatment for persistent pulmonary hypertension of the newborn.

OBJECTIVES

To determine whether treatment of hypoxaemic term and near-term newborn infants with inhaled nitric oxide (iNO) improves oxygenation and reduces the rates of death, the requirement for extracorporeal membrane oxygenation (ECMO), or affects long term neurodevelopmental outcomes.

SEARCH STRATEGY

Electronic and hand searching of pediatric/neonatal literature and personal data files. In addition we contacted the principal investigators of articles which have been published as abstracts to ascertain the necessary information.

SELECTION CRITERIA

Randomized and quasi-randomized studies of inhaled nitric oxide in term and near term infants with hypoxic respiratory failure. Clinically relevant outcomes, including death, requirement for ECMO, and oxygenation.

DATA COLLECTION AND ANALYSIS

Trial reports were analysed for methodologic quality using the criteria of the Cochrane Neonatal Review Group. Results of mortality, oxygenation, short term clinical outcomes (particularly need for ECMO), and long term developmental outcomes were tabulated.

STATISTICS

For categorical outcomes, typical estimates for relative risk and risk difference were calculated. For continuous variables, typical estimates for weighted mean difference were calculated. 95% confidence intervals were used. A fixed effect model was assumed for meta-analysis.

MAIN RESULTS

Fourteen eligible randomized controlled studies were found in term and near term infants with hypoxia. Seven of the trials compared iNO to control (placebo or standard care without iNO) in infants with moderate or severe severity of illness scores. Four of the trials compared iNO to control, but allowed back up treatment with iNO if the infants continued to satisfy the same criteria for severity of illness after a defined period of time. Two trials enrolled infants with moderate severity of illness score (OI or AaDO2) and randomized to immediate iNO treatment or iNO treatment only if they deteriorated to more severe criteria. One trial studied only infants with congenital diaphragmatic hernia (Ninos 1997), and one trial enrolled both preterm and term infants (Mercier 1998), but reported the majority of the results separately for the two groups. Inhaled nitric oxide appears to improve outcome in hypoxaemic term and near term infants by reducing the incidence of the combined endpoint of death or need for ECMO. The reduction seems to be entirely a reduction in need for ECMO; mortality is not reduced. Oxygenation improves in approximately 50% of infants receiving nitric oxide. The Oxygenation Index decreases by a (weighted) mean of 15.1 within 30 to 60 minutes after commencing therapy and PaO2 increases by a mean of 53 mmHg. Whether infants have clear echocardiographic evidence of persistent pulmonary hypertension of the newborn (PPHN) or not does not appear to affect outcome. The outcome of infants with diaphragmatic hernia was not improved; indeed there is a suggestion that outcome was slightly worsened. The incidence of disability, incidence of deafness and infant development scores are all similar between tested survivors who received nitric oxide or not.

AUTHORS' CONCLUSIONS

On the evidence presently available, it appears reasonable to use inhaled nitric oxide in an initial concentration of 20 ppm for term and near term infants with hypoxic respiratory failure who do not have a diaphragmatic hernia.

Neonatal ECMO: Current controversies and trends

Extracorporeal membrane oxygenation (ECMO), a technique for providing life support to patients with cardiac and/or respiratory dysfunction, allows the heart and lungs to "rest." The neonatal respiratory population has been a major benefactor of ECMO since 1982. Its use for neonatal respiratory disease increased dramatically until the past few years, when the number of neonatal respiratory ECMO cases began a downward trend. Fewer patients with persistent pulmonary hypertension of the newborn (PPHN), meconium aspiration syndrome, respiratory distress syndrome, or sepsis are requiring ECMO support as frequently as in the past. Many attribute this decline to the newer respiratory therapies-mainly, surfactant, high-frequency oscillatory ventilation, and inhaled nitric oxide. Neonates who continue to require ECMO today are sicker than the historic norm and have more complicated and lengthy ECMO runs. Patients with congenital diaphragmatic hernia, PPHN, and sepsis remain the most consistent in their representation among ECMO recipients within this author's institution, suggesting that the newer respiratory therapies have not had the same impact on these patients' needs for ECMO support. Better guidelines for determining which patients would benefit from earlier inititation of ECMO are needed.

Congenital diaphragmatic hernia: two case studies with atypical presentations

Congenital diaphragmatic hernia (CDH) affects 1 in every 2,000 to 4,000 live births. Many infants with this condition are diagnosed antenatally through routine ultrasound screening. Nearly 90 percent present at delivery with severe respiratory distress requiring intubation. Many of these infants develop persistent pulmonary hypertension of the newborn due to hypoplasia of the affected lung. The survival of infants with CDH is limited by the degree of pulmonary hypoplasia and requires sophisticated medical technology such as high-frequency ventilation and inhaled nitric oxide. Some infants also require treatment with extracoporeal membrane oxygenation. This article gives details of two cases of CDH in which the presentation was atypical. The more subtle presentation is discussed, as well as the embryology and pathophysiology of CDH and the possibility of associated anomalies. Clinical management and impact on the family are outlined.

A dose response study of inhaled nitric oxide in hypoxic respiratory failure in preterm infants

BACKGROUND

Inhaled nitric oxide (iNO) is used widely in newborn infants with hypoxic respiratory failure, despite the known and theoretical toxicity of iNO, and a relative lack of information about appropriate doses.

AIM

To determine whether a dose-response relationship existed for iNO in preterm infants.

DESIGN

A four-period, four-dose, cross-over design was used with iNO given for 15 min in a randomised sequence in concentrations of 5, 10, 20 and 40 parts per million (ppm), with a minimum 5 min wash-out period. Data on ventilatory, blood gas and other physiological measurements were recorded before and at the end of each period. The relationship of clinical response with iNO dose and period was analysed using multivariate regression.

SUBJECTS

Infants with gestational age < 34 weeks and < 28 days postnatal age with hypoxic respiratory failure were recruited.

OUTCOME MEASURE

A clinically significant dose-response was defined as a rise in the post-ductal arterial oxygen tension (PaO(2)) of at least 3 kPa.

RESULTS

Thirteen infants were recruited. At trial entry, ten were < 3 days of age; 11 were being treated with high frequency oscillatory ventilation; median (inter-quartile range) gestational age 27 (25-29) weeks; birthweight 983 (765-1120) g; oxygenation index 27.1 (21.8-28.8). Six infants (46%) showed a clinically significant response. After adjusting for period and patient effect, no evidence for an overall dose effect was identified (likelihood ratio test, p=0.34).

CONCLUSION

No evidence of a dose-response relationship with iNO was found in this study of very preterm infants with respiratory failure.

Mean airway pressure and response to inhaled nitric oxide in neonatal and pediatric patients

Inhaled nitric oxide (iNO) can improve oxygenation and ventilation-perfusion (V/Q) matching by reduction of shunt (Qs/Qt) in patients with hypoxemic lung disease. Because the improvement in V/Q matching must occur by redistribution of pulmonary blood flow, and because high airway pressure (Paw) increases physiologic dead space (Vd/Vt), we hypothesized that high Paw may limit the improvement in V/Q matching during iNO treatment. iNO 0-50 ppm was administered during mechanical ventilation. Mechanical ventilator settings were at the discretion of the attending physician. Qs/Qt and Vd/Vt were derived from a tripartite lung model with correction for shunt-induced dead space. Data from 62 patients during 153 trials were analyzed for effects of Paw and iNO on Qs/Qt and Vd/Vt. Baseline Qs/Qt was slightly increased at Paw 16-23 cmH2O (p < 0.05), while Vd/Vt increased progressively with higher Paw (p < 0.002). Therapy with iNO significantly reduced Qs/Qt (p < 0.001) at all levels of mean Paw, reaching a maximum reduction at 16-23 cmH2O (p < 0.05), such that Qs/Qt during iNO treatment was similar at all levels of Paw. During iNO treatment, a reduction in Vd/Vt occurred only at Paw of 8-15 cmH2O (p < 0.05), and the positive relationship between Vd/Vt and Paw was maintained. These differential effects on Qs/Qt and Vd/Vt suggest that both high and low Paw may limit improvement in gas exchange with iNO. Analysis of gas exchange using this corrected tripartite lung model may help optimize ventilatory strategies during iNO therapy.

Hypoxic respiratory failure in term newborns: clinical indicators for inhaled nitric oxide and extracorporeal membrane oxygenation therapy

PURPOSE

The criteria for starting extracorporeal membrane oxygenation (ECMO) therapy in term newborn patients with hypoxemic respiratory failure consist of an oxygenation index (OI) of 25 or higher and alveolar-arterial oxygen (Aao(2)) gradient of more than 600 at sea level. In such conditions, inhaled nitric oxide (iNO) may improve oxygenation and reduce the need for ECMO therapy. We studied early changes in OI and Aao(2) gradients in response to iNO treatment that may indicate a need to continue iNO treatment or the necessity to start an ECMO therapy.

MATERIALS AND METHODS

In this prospective study, we used 34 outborn neonatal patients that were referred to our pediatric critical care unit in a children's hospital for ECMO therapy with diagnosis of hypoxemic respiratory failure. In all patients, iNO therapy, starting at 80 ppm, was instituted either during transport or on arrival to hospital. Response to iNO was assessed after 1 hour, at which time, iNO concentration was reduced to 40 ppm, provided there was more than 20% improvement in either or both oxygenation indices. Patients who did not respond positively to continuous iNO therapy and met ECMO criteria were given ECMO therapy.

RESULTS

Inhaled nitric oxide therapy alone was successful in 10 (29%) of 34 patients. Eighteen patients (53%) required ECMO therapy within the first 10 hours of iNO treatment (early ECMO therapy), whereas 6 other neonates (18%) became eligible for ECMO therapy after prolonged (2-4 days) iNO treatment (late ECMO therapy). No mortality occurred with any treatment. Within 4 hours after iNO therapy, patients who required early ECMO therapy had significantly higher OI and Aao(2) gradients than patients who were treated with iNO therapy alone (P<.01, analysis of variance followed by Tukey-Kramer multiple comparison test). Six of 34 patients (18%), categorized as late ECMO therapy, on the average, had initially higher levels of OI and mean airway pressure than neonates in iNO treatment and early ECMO therapy.

CONCLUSION

Persisting levels of OI of more than 20 or Aao(2) gradients of more than 600 after 4 hours of iNO therapy could be indicative of an immediate need for ECMO therapy.

Update on extracorporeal life support 2004

Since its beginnings in 1989, the Extracorporeal Life Support Organization (ELSO) Registry has collated and reported data on over 30,000 patients. The majority of patients entered into the Registry have been neonates with respiratory failure from meconium aspiration, persistent pulmonary hypertension, or congenital diaphragmatic hernia. These patients suffer from refractory hypoxemia; thus, this supportive technique came to be called "Extracorporeal Membrane Oxygenation (ECMO)" for its ability to provide excellent gas exchange. With advances in prevention, diagnosis, and treatment measures for neonatal respiratory failure, need for ECMO support has fallen from the peak of 1500 cases in the early 1990s to 800 cases annually. Sixty-six percent (over 19,000) of patients in the Registry are under the category of neonatal respiratory failure, with a 77% overall survival reported to discharge. The success of neonatal ECMO has led to expansion of the field to pediatric, cardiac, and adult patients. An average of 200 pediatric patients receive ECMO for respiratory failure per year with an overall survival of 55%. Adult respiratory failure patients form a smaller group, with less than 100 cases reported to the ELSO registry per year. Survival mirrors that noted in the pediatric ECMO population. The application of ECMO or related techniques continues to increase for cardiac failure across all age groups. Overall survival in cardiac patients ranges from 33% to 43%. A novel form of extracorporeal support is "ECPR" or ECMO during cardiac arrest. Bypass circuits and equipment can be set up and instituted within a very short period of time in this circumstance, thus the name "rapid deployment ECMO" has become associated with this form of support. Overall survival in the near-600 patients placed on ECMO during resuscitation is 40%.

New approaches for persistent pulmonary hypertension of newborn

The management of PPHN entered a new era with the development of inhaled NO therapy for the relief of pulmonary hypertension. The wider application of INO therapy and improved ventilation strategies led to a decrease in the need for invasive life-sustaining therapies such as ECMO. The remarkable advances in the understanding and treatment of PPHN were made possible by the extensive investigations in the laboratory using animal models. Further decreases in morbidity and mortality are possible with specific strategies targeted to correct the alterations in NO and prostacyclin biology and strategies to reduce lung injury. Further research is needed to understand the basis for the biologic susceptibility of some infants to environmental insults such as intra-uterine stressor exposure to NSAIDs in utero.

Total Intravenous Anesthesia for Repair of Congenital Diaphragmatic Hernia: A Case Report

Congenital diaphragmatic hernia is a cardiopulmonary anomaly that causes severe respiratory disorder. Traditionally, inhalational anesthetics with mechanical hyperventilation, opioids, and muscle relaxants are used in anesthesia for repair surgery. In this case, we used total intravenous anesthesia combined with high-frequency oscillatory ventilation and inhaled nitric oxide for surgical repair of the diaphragm. After surgery, the patient recovered well and was discharged from hospital 1 month later.