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

Efficacy of inhaled nitric oxide in preterm infants ≤ 34 weeks: a systematic review and meta-analysis of randomized controlled trials

Background: The effect of inhaled nitric oxide (iNO) in neonates >34 weeks on improving respiration is well documented. However, the efficacy of iNO in preterm infants ≤34 weeks remains controversial. Objectives: The main purpose of this review is to assess the effectiveness and safety of iNO treatment in preterm infants ≤34 weeks. Search methods: We systematically searched PubMed, Embase and Cochrane Libraries from their inception to 1 June 2023. We also reviewed the reference lists of retrieved studies. Selection criteria: Our study involved randomized controlled trials on preterm infants ≤34 weeks, especially those receiving iNO treatment, and mainly assessed outcomes such as bronchopulmonary dysplasia (BPD) and mortality. Two authors independently reviewed these trials, extracted data, and evaluated study biases. Disagreements were resolved by consensus. We used the GRADE method to assess evidence quality. Results: Our research included a total of 17 studies involving 4,080 neonates and 7 follow-up studies. The synthesis of results showed that in neonates, iNO treatment reduced the incidence of BPD (RR: 0.92; 95% CI: 0.86-0.98). It also decreased the composite outcome of death or BPD (RR: 0.94; 95% CI: 0.90-0.98), without increasing the risk of short-term (such as intraventricular hemorrhage, periventricular leukomalacia) and long-term neurological outcomes (including Bayley mental developmental index <70, cerebral palsy and neurodevelopmental impairment). Furthermore, iNO did not significantly affect other neonatal complications like sepsis, pulmonary hemorrhage, necrotizing enterocolitis, and symptomatic patent ductus arteriosus. Subgroup analysis revealed that iNO significantly reduced BPD incidence in neonates at 36 weeks under specific intervention conditions, including age less than 3 days, birth weight over 1,000 g, iNO dose of 10 ppm or higher, or treatment duration exceeding 7 days (p < 0.05). Conclusion: Inhaled NO reduced the incidence of BPD in neonates at 36 weeks of gestation, and the effect of the treatment depended on neonatal age, birth weight, duration and dose of iNO. Therefore, iNO can be considered a promising treatment for the potential prevention of BPD in premature infants. More data, however, would be needed to support nitric oxide registration in this specific patient population, to minimize its off-label use.

Early use of combined exogenous surfactant and inhaled nitric oxide reduces treatment failure in persistent pulmonary hypertension of the newborn: a randomized controlled trial

OBJECTIVE

To evaluate whether combined surfactant with inhaled nitric oxide (iNO) use will prevent newborns with hypoxemic respiratory failure (HRF) from developing an Oxygenation Index (OI) > 40.

METHODS

100 term newborns with acute HRF (OI ≥ 20) were randomized to: Surfactant+iNO: received iNO plus up to two doses of surfactant or iNO-Controls: received iNO+placebo. Main outcome was the development of severe HRF (OI > 40) despite iNO use.

RESULTS

Baseline mean ± SD OI was 37.4 ± 14 for the Surfactant+iNO group and 38.2 ± 16 for the controls. Infants receiving surfactant+iNO improved their oxygenation faster, resulting in lower OI at 24 h: 12.9 ± 9 vs 18.7 ± 11 of controls, p < 0.05; and a lower proportion developing OI > 40: 24%(12/50) vs 50%(25/50) of controls, p < 0.02. Fewer infants receiving surfactant+iNO presented the combined outcome of death or ECMO: 16%(8/50) compared to 36%(18/50) of controls, p < 0.05.

CONCLUSIONS

Early use of combined surfactant+iNO improves oxygenation preventing the progression to severe HRF. This may reduce mortality and ECMO need.

TRIAL REGISTRATION NUMBER

ISRCTN13727958.

The Controversy Persists: Is There a Qualification Criterion to Utilize Inhaled Nitric Oxide in Pre-term Newborns?

Inhaled nitric oxide (iNO) use in premature newborns remains controversial among clinicians. In 2014, the American Academy of Pediatrics, Committee on Fetus and Newborn released a statement that the available data do not support routine iNO use in pre-term newborns. Despite the absence of significant benefits, 2016 California data showed that clinicians continue to utilize iNO in pre-term infants. With studies as recent as January 2017, the Cochrane review confirmed no major advantages of iNO in pre-term newborns. Still, it recognized that a subset of pre-term infants with pulmonary hypertension (PHTN) had not been separately investigated. Furthermore, recent non-randomized controlled trials have suggested that iNO may benefit specific subgroups of pre-term newborns, especially those with PHTN, prolonged rupture of membranes, and antenatal steroid exposure. Those pre-term infants who showed a clinical response to iNO had increased survival without disability. These findings underscore the need for future studies in pre-term newborns with hypoxemic respiratory failure and PHTN. This review will discuss the rationale for using iNO, controversies regarding the diagnosis of PHTN, and additional novel approaches of iNO treatment in perinatal asphyxia and neonatal resuscitation in the pre-term population < 34 weeks gestation.

Nitric oxide as a therapeutic option for COVID-19 treatment: a concise perspective

Among several possible therapies applicable for treating COVID-19, nitric oxide therapy has also gained considerable interest. This article describes the same with mechanistic details.

The use of milrinone in neonates with persistent pulmonary hypertension of the newborn - a randomised controlled trial pilot study (MINT 1): study protocol and review of literature

Persistent pulmonary hypertension of the newborn (PPHN) is a relatively common condition which results in a mortality of up to 33%. Up to 40% of infants treated with nitric oxide (iNO) either have a transient response or fail to demonstrate an improvement in oxygenation. Milrinone, a selective phosphodiesterase 3 (PDE3) inhibitor with inotropic and lusitropic properties may have potential benefit in PPHN. This pilot study was developed to assess the impact of milrinone administration on time spent on iNO in infants with PPHN. This is a multicentre, randomized, double-blind, two arm pilot study, with a balanced (1:1) allocation of 20 infants. In this pilot study, we hypothesise that infants ≥34 weeks gestation and ≥ 2000 g with a clinical and echocardiography diagnosis of PPHN, intravenous milrinone used in conjunction with iNO will result in a reduction in the time spent on iNO. In addition, we hypothesise that milrinone treatment will lead to an improvement in myocardial performance and global hemodynamics when compared to iNO alone. We will also compare the rate of adverse events associated with the milrinone, and the pre-discharge outcomes of both groups. The purpose of this pilot study is to assess the feasibility of performing the trial and to obtain preliminary data to calculate a sample size for a definitive multi-centre trial of milrinone therapy in PPHN. Trial registration: www.isrctn.com; ISRCTN:12949496; EudraCT Number:2014-002988-16.

Insights on Localized and Systemic Delivery of Redox-Based Therapeutics

Reactive oxygen and nitrogen species are indispensable in cellular physiology and signaling. Overproduction of these reactive species or failure to maintain their levels within the physiological range results in cellular redox dysfunction, often termed cellular oxidative stress. Redox dysfunction in turn is at the molecular basis of disease etiology and progression. Accordingly, antioxidant intervention to restore redox homeostasis has been pursued as a therapeutic strategy for cardiovascular disease, cancer, and neurodegenerative disorders among many others. Despite preliminary success in cellular and animal models, redox-based interventions have virtually been ineffective in clinical trials. We propose the fundamental reason for their failure is a flawed delivery approach. Namely, systemic delivery for a geographically local disease limits the effectiveness of the antioxidant. We take a critical look at the literature and evaluate successful and unsuccessful approaches to translation of redox intervention to the clinical arena, including dose, patient selection, and delivery approach. We argue that when interpreting a failed antioxidant-based clinical trial, it is crucial to take into account these variables and importantly, whether the drug had an effect on the redox status. Finally, we propose that local and targeted delivery hold promise to translate redox-based therapies from the bench to the bedside.

Controversies in the identification and management of acute pulmonary hypertension in preterm neonates

It is increasingly recognized that the abnormal physiologic consequences of pulmonary hypertension (PH) may contribute to poor cardiopulmonary health in premature babies. Conflicting literature has led to clinical uncertainty, pathological misinterpretation, and variability in treatment approaches among practitioners. There are several disorders with overlapping and interrelated presentations, and other disorders with a similar clinical phenotype but diverse pathophysiological contributors. In this review, we provide a diagnostic approach for acute hypoxemic respiratory failure in the preterm neonate, outline the pathophysiological conditions that may present as acute PH, and discuss the implications of high pulmonary vascular resistance (PVR) on the cardiovascular system. Although PVR and respiratory management are highly interrelated, there may be a population of preterm neonates in whom inhaled nitric oxide may improve illness severity and may relate to outcomes. A management approach based on physiology that considers common clinical conundrums is provided. A more comprehensive understanding of the physiology may help in informed decision-making in clinical situations where conclusive scientific evidence is lacking. Regardless, high-quality research is required, and appropriate definition of the target population is paramount. A thoughtful approach to cardiovascular therapy may also provide an avenue to improve neurodevelopmental outcomes while awaiting more clear answers.

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.

Inhaled nitric oxide for respiratory failure in preterm infants

BACKGROUND

Inhaled nitric oxide (iNO) is effective in term infants with hypoxic respiratory failure. The pathophysiology of respiratory failure and the potential risks of iNO differ substantially in preterm infants, necessitating specific study in this population.

OBJECTIVES

To determine effects of treatment with inhaled nitric oxide (iNO) on death, bronchopulmonary dysplasia (BPD), intraventricular haemorrhage (IVH) or other serious brain injury and on adverse long-term neurodevelopmental outcomes in preterm newborn infants with hypoxic respiratory failure.Owing to substantial variation in study eligibility criteria, which decreases the utility of an overall analysis, we divided participants post hoc into three groups: (1) infants treated over the first three days of life because of defects in oxygenation, (2) preterm infants with evidence of pulmonary disease treated routinely with iNO and (3) infants treated later (after three days of age) because of elevated risk of BPD.

SEARCH METHODS

We used standard methods of the Cochrane Neonatal Review Group. We searched MEDLINE, Embase, Healthstar and the Cochrane Central Register of Controlled Trials in the Cochrane Library through January 2016. We also searched the abstracts of the Pediatric Academic Societies.

SELECTION CRITERIA

Eligible for inclusion were randomised and quasi-randomised studies in preterm infants with respiratory disease that compared effects of iNO gas versus control, with or without placebo.

DATA COLLECTION AND ANALYSIS

We used standard methods of the Cochrane Neonatal Review Group and applied the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess the quality of evidence.

MAIN RESULTS

We found 17 randomised controlled trials of iNO therapy in preterm infants. We grouped these trials post hoc into three categories on the basis of entry criteria: treatment during the first three days of life for impaired oxygenation, routine use in preterm babies along with respiratory support and later treatment for infants at increased risk for bronchopulmonary dysplasia (BPD). We performed no overall analyses.Eight trials providing early rescue treatment for infants on the basis of oxygenation criteria demonstrated no significant effect of iNO on mortality or BPD (typical risk ratio (RR) 0.94, 95% confidence interval (CI) 0.87 to 1.01; 958 infants). Four studies examining routine use of iNO in infants with pulmonary disease reported no significant reduction in death or BPD (typical RR 0.94, 95% CI 0.87 to 1.02; 1924 infants), although this small effect approached significance. Later treatment with iNO based on risk of BPD (three trials) revealed no significant benefit for this outcome in analyses of summary data (typical RR 0.92, 95% CI 0.85 to 1.01; 1075 infants).Investigators found no clear effect of iNO on the frequency of all grades of IVH nor severe IVH. Early rescue treatment was associated with a non-significant 20% increase in severe IVH.We found no effect on the incidence of neurodevelopmental impairment.

AUTHORS' CONCLUSIONS

iNO does not appear to be effective as rescue therapy for the very ill preterm infant. Early routine use of iNO in preterm infants with respiratory disease does not prevent serious brain injury or improve survival without BPD. Later use of iNO to prevent BPD could be effective, but current 95% confidence intervals include no effect; the effect size is likely small (RR 0.92) and requires further study.

Diverse Morbidity and Mortality Among Infants Treated with Venoarterial Extracorporeal Membrane Oxygenation

Background: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is utilized for cardiopulmonary failure. We aimed to qualify and quantify the predictors of morbidity and mortality in infants requiring VA-ECMO.

Methods: Data was collected from 170 centers participating in the extracorporeal life support organization (ELSO) registry. Relationships between in-hospital mortality and risk factors were assessed using logistic regression. Survival was defined as being discharged from the hospital.

Results: Six hundred and sixty-two eligible records were reviewed. Mortality occurred in 303 (46%) infants. Congenital diaphragmatic hernia patients (OR=3.83, 95% CI 1.96-7.49, p<0.001), cardiac failure with associated shock (OR= 2.90, 95% CI 1.46-5.77, p=0.002), and pulmonary failure including respiratory distress syndrome (OR=4.06, 95% CI 1.72-9.58, p=0.001) had the highest odds of mortality in this cohort. Birth weight (BW) < 3 kg (OR=1.83, 95% CI 1.21-2.78, p=0.004), E-CPR (OR=3.35, 95% CI 1.57-7.15, p=0.002), hemofiltration (OR=2.04, 95% CI 1.32-3.16, p=0.001), and dialysis (OR=6.13, 95% CI 1.70-22.1, p<0.001) were all independent predictors of mortality.

Conclusion: Infants requiring VA-ECMO experience diverse sequelae and their mortality are high.

A role for actin polymerization in persistent pulmonary hypertension of the newborn

Persistent pulmonary hypertension of the newborn (PPHN) is defined as the failure of normal pulmonary vascular relaxation at birth. Hypoxia is known to impede postnatal disassembly of the actin cytoskeleton in pulmonary arterial myocytes, resulting in elevation of smooth muscle α-actin and γ-actin content in elastic and resistance pulmonary arteries in PPHN compared with age-matched controls. This review examines the original histological characterization of PPHN with attention to cytoskeletal structural remodeling and actin isoform abundance, reviews the existing evidence for understanding the biophysical and biochemical forces at play during neonatal circulatory transition, and specifically addresses the role of the cortical actin architecture, primarily identified as γ-actin, in the transduction of mechanical force in the hypoxic PPHN pulmonary circuit.

Inhaled nitric oxide for the postoperative management of pulmonary hypertension in infants and children with congenital heart disease

BACKGROUND

Nitric oxide (NO) is a prevalent molecule in humans that is responsible for many physiologic activities including pulmonary vasodilation. An exogenous, inhaled form (iNO) exists that mimics this action without affecting systemic blood pressure. This therapy has been implemented in the treatment of pulmonary hypertension. This review examines the efficacy of iNO in the postoperative management of infants and children with congenital heart disease (CHD). The original review was published in 2005, updated in 2008 and again in 2014.

OBJECTIVES

To compare the effects of postoperative administration of iNO versus placebo or conventional management, or both, on infants and children with CHD and pulmonary hypertension. The primary outcome was mortality. Secondary outcomes included length of hospital stay; neurodevelopmental disability; number of pulmonary hypertensive crises (PHTC); changes in mean pulmonary arterial pressure (MPAP), mean arterial pressure (MAP), and heart rate (HR); changes in oxygenation measured as the ratio of arterial oxygen tension (PaO2) to fraction of inspired oxygen (FiO2); and measurement of maximum methaemoglobin level as a marker of toxicity.

SEARCH METHODS

In this updated version we extended the CENTRAL search to 2013, Issue 12 of The Cochrane Library, and MEDLINE and EMBASE through to 1 December 2013. The original search was performed in July 2004 and again in November 2007. We included abstracts and all languages.

SELECTION CRITERIA

We included randomized and quasi-randomized controlled trials comparing iNO with placebo or conventional management, or both. Trials included only children with CHD requiring surgery complicated by pulmonary hypertension.

DATA COLLECTION AND ANALYSIS

Two authors extracted data. Data were collected on mortality; number of PHTC; changes in MPAP, MAP, HR, and PaO2:FiO2; and maximum methaemoglobin level. Data on long-term mortality, neurodevelopmental disability, and length of hospital stay were unavailable. We performed subgroup analysis by method of control (placebo or conventional management).

MAIN RESULTS

We reran the searches to December 2013 and identified three new studies. These three studies did not fulfil our inclusion criteria. Therefore, no new studies were included in this updated review. In total four randomized trials involving 210 participants were included in this review. We observed no differences in mortality (OR 1.67, 95% CI 0.38 to 7.30; P = 0.50); PHTC (OR 0.80, 95% CI 0.15 to 4.18; P = 0.79); changes in MPAP (treatment effect -2.94 mm Hg, 95% CI -9.28 to 3.40; P = 0.36), MAP (treatment effect -3.55 mm Hg, 95% CI -11.86 to 4.76; P = 0.40), HR (treatment effect 0.02 bpm, 95% CI -8.13 to 8.18; P = 1.00), or PaO2:FiO2 (mean difference 17.18, 95% CI -28.21 to 62.57; P = 0.46). There was a significant increase in the methaemoglobin level (mean difference 0.30%, 95% CI 0.24 to 0.36; P < 0.00001) in patients treated with iNO, although levels did not reach toxicity levels. Data from long-term mortality, neurodevelopmental disability, and length of stay were not available. Two trials had a low risk of bias. Very low quality of the evidence was observed considering grading of the outcomes.

AUTHORS' CONCLUSIONS

We observed no differences with the use of iNO in the outcomes reviewed. No data were available for several clinical outcomes including long-term mortality and neurodevelopmental outcome. We found it difficult to draw valid conclusions given concerns regarding methodologic quality, sample size, and heterogeneity.

Update on PPHN: mechanisms and treatment

Persistent pulmonary hypertension of the newborn (PPHN) is a syndrome of failed circulatory adaptation at birth, seen in about 2/1000 live born infants. While it is mostly seen in term and near-term infants, it can be recognized in some premature infants with respiratory distress or bronchopulmonary dysplasia. Most commonly, PPHN is secondary to delayed or impaired relaxation of the pulmonary vasculature associated with diverse neonatal pulmonary pathologies, such as meconium aspiration syndrome, congenital diaphragmatic hernia, and respiratory distress syndrome. Gentle ventilation strategies, lung recruitment, inhaled nitric oxide, and surfactant therapy have improved outcome and reduced the need for extracorporeal membrane oxygenation (ECMO) in PPHN. Newer modalities of treatment discussed in this article include systemic and inhaled vasodilators like sildenafil, prostaglandin E1, prostacyclin, and endothelin antagonists. With prompt recognition/treatment and early referral to ECMO centers, the mortality rate for PPHN has significantly decreased. However, the risk of potential neurodevelopmental impairment warrants close follow-up after discharge for infants with PPHN.

Patch repair is an independent predictor of morbidity and mortality in congenital diaphragmatic hernia

BACKGROUND

Infants with congenital diaphragmatic hernia (CDH) have variable outcomes. There is a considerable potential benefit in being able to predict perinatally, which infants have severe hypoplasia and are thus more likely to die or survive with significant morbidity. We examine the relationship between a need for patch repair of CDH (PR) and outcome, using a national database.

METHODS

Baseline characteristics of patients undergoing PR or non-patch repair (NPR) were compared. Multivariate analysis was performed to determine the association of PR with mortality and morbidity independent of other known predictors.

RESULTS

Baseline characteristics of PR and NPR infants were similar although those infants with PR had higher SNAP-II scores. PR was an independent predictor of mortality with an odds ratio of 17.1 (95%CI 2.0-149.2) and was independently associated with secondary outcome measures of morbidity, including the need for oxygen at discharge and the duration of ventilation.

CONCLUSIONS

Infants requiring PR have significantly higher mortality and suffer greater morbidity than those undergoing NPR. This association is independent of other known predictors of mortality. Identifying prenatal features associated with this high risk group would be of great clinical value.

Meconium Aspiration Syndrome: An Insight

Meconium aspiration syndrome (MAS) is respiratory distress in a newborn baby caused by the presence of meconium in the tracheobronchial airways. The aspiration of meconium stained amniotic fluid by the fetus can happen during antepartum or intrapartum periods and can result in airway obstruction, interference with alveolar gas exchange, chemical pneumonitis as well as surfactant dysfunction. These pulmonary effects cause gross ventilation-perfusion mismatching. To complicate matters further, many infants with MAS have primary or secondary persistent pulmonary hypertension of the newborn as a result of chronic in utero stress and thickening of the pulmonary vessels. Although meconium is sterile, its presence in the air passages can predispose the infant to pulmonary infection. MAS is essentially a clinical diagnosis and should always be suspected in a child with respiratory distress and meconium-stained amniotic fluid at delivery. Though a known entity for a long time, its management still remains contentious. Intubation and direct tracheal suction is performed when meconium is observed in the amniotic fluid and the infant is not vigorous. Subsequent management involves ventilation, surfactant instillation and lavage, inhaled nitric oxide and high frequency ventilation. The role of steroids continues to be controversial.

Congenital diaphragmatic hernia: current status and review of the literature

Treatment of congenital diaphragmatic hernia (CDH) challenges obstetricians, pediatric surgeons, and neonatologists. Persistent pulmonary hypertension (PPHT) associated with lung hypoplasia in CDH leads to a high mortality rate at birth. PPHT is principally due to an increased muscularization of the arterioles. Management of CDH has been greatly improved by the introduction of prenatal surgical intervention with tracheal obstruction (TO) and by more appropriate postnatal care. TO appears to accelerate fetal lung growth and to increase the number of capillary vessels and alveoli. Improvement of postnatal care over the last years is mainly due to the avoidance of lung injury by applying low peak inflation pressure during ventilation. The benefits of other drugs or technical improvements such as the use of inhaled nitric oxide or extracorporeal membrane oxygenation (ECMO) are still being debated and no single strategy is accepted worldwide. Despite intensive clinical and experimental research, the treatment of newborn with CDH remains difficult.

Nitric oxide administration using an oxygen hood: a pilot trial

BACKGROUND

We have shown earlier that inhaled nitric oxide (iNO) administered by oxygen hood reduces pulmonary hypertension in an animal model (J Perinatol 2002; 22:50-6). Our objective in this study was to determine feasibility of iNO by oxygen hood in neonates with elevated alveolar-arterial oxygen gradients (A-aDO(2)).

METHODS/PRINCIPAL FINDINGS

Masked randomized controlled pilot trial. Inclusion criteria were: gestation>or=34 weeks, age<7 days, with post-ductal arterial line, and A-aDO(2) 400-600. Infants were randomized to study gas (iNO 20 ppm or equivalent O(2) flow) for 1 hr which was then weaned over the next 4 hours. Primary outcome was PaO(2) one hour post-randomization. Four infants each were randomized to iNO or O(2) (controls). Two of the four infants given iNO had an increase in PaO(2) of >100 torr, while oxygenation was unchanged in the controls. Methemoglobinemia and other adverse effects were not noted in any infant. Environmental levels of NO and NO(2) were minimal (<1 ppm) at >0.3 m from the hood.

CONCLUSIONS

Administration of iNO by oxygen hood is feasible. Larger randomized controlled trials are required to measure the efficacy and determine an appropriate target population for this technique.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00041548.

What is new in ventilation strategies for the neonate?

A large number of ventilation strategies are now available for the neonate. This review has focused on new information, that is, studies published since 2000 and the implication of their results for current clinical practice. Meta-analysis of randomised trials has demonstrated that assist control and synchronous intermittent mandatory ventilation (SIMV) shortens the duration of ventilation only if started in the recovery rather than the early stage of respiratory disease. A recent randomised trial demonstrated pressure-regulated volume control ventilation may also have no advantages if started early. Weaning by SIMV with pressure support is better (reducing oxygen dependency) than SIMV alone. Meta-analysis of volume-targeted ventilation demonstrated significant reductions in the duration of ventilation and pneumothorax, but the trials were small and of different designs. Volume guarantee may provide more consistent blood gas control. The level of volume targeting appears to be crucial to the success of this technique. Meta-analysis of randomised trials of prophylactic high-frequency oscillation trials has shown a modest reduction in bronchopulmonary dysplasia. Randomised trials have failed to confirm the advantages of nasal continuous positive airway pressure (NCPAP) seen in various non-randomised studies; however, the randomised trials reported to date have been small. Inhaled nitric oxide (NO) does not improve the outcome of prematurely born infants with severe respiratory failure, but early low-dose prolonged iNO appears to have benefits that merit further testing. More randomised trials with long-term outcomes are required to identify the optimal ventilation strategy(ies) for the neonate.

How does the changing profile of infants who are referred for extracorporeal membrane oxygenation affect their overall respiratory outcome?

OBJECTIVE

Extracorporeal membrane oxygenation has been shown to be effective in term neonates with severe but reversible lung disease within the context of randomized, controlled trials. Extracorporeal membrane oxygenation now has been open to a wider population of infants in the United Kingdom, and other treatments have become available. The population referred for extracorporeal membrane oxygenation, therefore, has changed. The aims of this study were to (1) compare respiratory outcomes of infants who received extracorporeal membrane oxygenation in recent years with those from 10 years ago and (2) determine whether respiratory outcome varied with diagnostic group.

METHODS

All infants who were referred to a single extracorporeal membrane oxygenation center and were <12 months old during a 7-year period were eligible. One year after extracorporeal membrane oxygenation, lung volume, airway conductance, maximum expiratory flow, and indices of tidal breathing were measured.

RESULTS

A total of 106 infants (77% of those eligible) were tested, and results were compared with those of 51 infants referred for extracorporeal membrane oxygenation as part of the original United Kingdom extracorporeal membrane oxygenation trial. Lung volume was not different, but there was a strong trend for the infants who were seen in more recent years to have better forced expiratory flow and specific airway conductance. Restricting analysis to the major subgroup (meconium aspiration) confirmed these findings. When divided into diagnostic subgroups, infants who required extracorporeal membrane oxygenation for respiratory distress syndrome or who were >2 weeks old when extracorporeal membrane oxygenation was commenced had a poorer respiratory outcome than others.

CONCLUSIONS

The respiratory outcome of infants who were treated beyond the tightly regulated criteria of the United Kingdom trial remains good and even shows a trend toward improvement. Certain subgroups require extracorporeal membrane oxygenation for longer and have poorer pulmonary function when followed up.

Congenital diaphragmatic hernia: a systematic review and summary of best-evidence practice strategies

OBJECTIVES

Recent reports suggest that specific care strategies improve survival of infants with congenital diaphragmatic hernia (CDH). This review presents details of care from centers reporting high rates of survival among CDH infants.

STUDY DESIGN

We conducted a MEDLINE search (1995 to 2006) and searched all citations in the Cochrane Central Register of Controlled Trials. Studies were included if they contained reports of >20 infants with symptomatic CDH, and >75% survival of isolated CDH.

RESULT

Thirteen reports from 11 centers met inclusion criteria. Overall survival, including infants with multiple anomalies, was 603/763 (79%; range: 69 to 93%). Survival for isolated CDH was 560/661 (85%; range: 78 to 96%). The frequency of extracorporeal membrane oxygenation (ECMO) use for isolated CDH varied widely among reporting centers 251/622 (40%; range: 11 to 61%), as did survival for infants with isolated CDH placed on ECMO: 149/206 (73%; range: 33 to 86%). There was no suggestion of benefit from use of antenatal glucocorticoids given after 34 weeks gestation or use of postnatal surfactant. Low mortality was frequently attributed to minimizing lung injury and adhering to center-specific criteria for ECMO.

CONCLUSION

Use of strategies aimed at minimizing lung injury, tolerance of postductal acidosis and hypoxemia, and adhering to center-specific criteria for ECMO were strategies most consistently reported by successful centers. The literature lacks randomized clinical trials of these or other care strategies in this complex patient population; prospective studies of safety and long-term outcome are needed.

The hemodynamically significant ductus arteriosus in critically ill full-term neonates. Two case reports?

In premature infants, the clinical effects and management of a hemodynamically significant patent ductus arteriosus (HSDA) are well-described. In full-term neonates the ductus arteriosus (DA) is rarely monitored except in cases of concomitant pulmonary hypertension or duct dependent congenital heart disease. Although systemic-pulmonary shunting commonly occurs in mature infants, coinciding with the normal postnatal fall in pulmonary vascular resistance, cardiac failure in the neonatal period is rarely attributed directly to the DA. In this case series, we report two full-term infants who were initially treated for pulmonary hypertension and myocardial dysfunction but developed clinical, radiographic and two-dimensional echocardiographic evidence of cardiac failure secondary to a large unrestrictive patent DA (PDA). One patient was treated with indomethacin, and, although transductal diameter decreased, there was no clinical benefit. Cardiac failure resolved and myocardial function improved in both cases after PDA ligation. We suggest that PDA be monitored closely in neonates recovering from PPHN who have ongoing oxygenation difficulties or myocardial failure. PDA ligation should be considered an option for full term neonates with cardiac failure secondary to a HSDA when other therapeutic options fail.

Thromboxane hypersensitivity in hypoxic pulmonary artery myocytes: altered TP receptor localization and kinetics

Hypoxia-induced neonatal persistent pulmonary hypertension (PPHN) is characterized by sustained vasospasm and increased thromboxane (TxA2)-to-prostacyclin ratio. We previously demonstrated that moderate hypoxia induces myocyte TxA2 hypersensitivity. Here, we examined TxA2 prostanoid receptor (TP-R) localization and kinetics following hypoxia to determine the mechanism of hypoxia-induced TxA2 hypersensitivity. Primary cultured neonatal pulmonary artery myocytes were exposed to 10% O2 (hypoxic myocytes; HM) or 21% O2 (normoxic myocytes; NM) for 3 days. PPHN was induced in neonatal piglets by in vivo exposure to 10% FiO2 for 3 days. TP-R was studied in whole lung sections from pigs with hypoxic PPHN- and age-matched controls; intracellular localization was studied by immunocytochemistry. TP-R affinity was studied in cultured myocytes by saturation binding kinetics using 3H-SQ-29548 and competitive binding kinetics by coincubation with U-46619. Phosphorylation and coupling were examined in immunoprecipitated TP-R. We report distal propagation of TP-R expression in PPHN, extending to pulmonary arteries <50 microm. In HM, intracellular TP-R moves towards the perinuclear region, mirroring a change in endoplasmic reticulum (ER) morphology. TP-R kinetics also alter in HM membranes, with decreased Kd and Bmax (maximal binding sites). Additionally, in hypoxia, 3H-SQ-29548 is displaced at lower concentration of U-46619 than in normoxia, suggesting increased agonist affinity. Phosphorylation of serine residues on HM TP-R was significantly decreased compared with NM; this difference correlated with increased Galphaq coupling in hypoxia and was ablated by incubation with PKA. We conclude that the TP-R is normally desensitized in the neonatal pulmonary circuit by PKA-mediated regulatory phosphorylation, decreasing ligand affinity and coupling to Galphaq; this protection is lost following hypoxic exposure. Also, the appearance of TP-R in resistance arteries after development of hypoxic PPHN may contribute to increased pulmonary arterial pressure.

Treatment evolution in high-risk congenital diaphragmatic hernia: ten years' experience with diaphragmatic agenesis

OBJECTIVE

The objective of this study was to evaluate the impact of newer therapies on the highest risk patients with congenital diaphragmatic hernia (CDH), those with agenesis of the diaphragm.

SUMMARY BACKGROUND DATA

CDH remains a significant cause of neonatal mortality. Many novel therapeutic interventions have been used in these infants. Those children with large defects or agenesis of the diaphragm have the highest mortality and morbidity.

METHODS

Twenty centers from 5 countries collected data prospectively on all liveborn infants with CDH over a 10-year period. The treatment and outcomes in these patients were examined. Patients were followed until death or hospital discharge.

RESULTS

A total of 1,569 patients with CDH were seen between January 1995 and December 2004 in 20 centers. A total of 218 patients (14%) had diaphragmatic agenesis and underwent repair. The overall survival for all patients was 68%, while survival was 54% in patients with agenesis. When patients with diaphragmatic agenesis from the first 2 years were compared with similar patients from the last 2 years, there was significantly less use of ECMO (75% vs. 52%) and an increased use of inhaled nitric oxide (iNO) (30% vs. 80%). There was a trend toward improved survival in patients with agenesis from 47% in the first 2 years to 59% in the last 2 years. The survivors with diaphragmatic agenesis had prolonged hospital stays compared with patients without agenesis (median, 68 vs. 30 days). For the last 2 years of the study, 36% of the patients with agenesis were discharged on tube feedings and 22% on oxygen therapy.

CONCLUSIONS

There has been a change in the management of infants with CDH with less frequent use of ECMO and a greater use of iNO in high-risk patients with a potential improvement in survival. However, the mortality, hospital length of stay, and morbidity in agenesis patients remain significant.

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.

Perinatal asphyxia pathophysiology in pig and human: A review

In utero fetuses are evidently exposed to several factors that cause an interruption of the oxygen flow through the umbilical cord causing asphyxia leading to hypoxia and metabolic acidosis. These conditions are important causes of intra-partum and neonatal mortality. The main objective of this review is to provide current information regarding the pathophysiology of asphyxia in piglets around parturition; the physiological mechanisms invoked by affected piglets to compensate perinatal hypoxemia are discussed. This review also addresses some similarities and differences of asphyxia between piglets and other mammals, including human neonates. Metabolic acidosis and hypoxia are sequela to asphyxia and can cause profound health effects in postnatal performance because of an abnormal suckling, a reduced absorption of colostrum and inadequate passive transfer of neonatal immunity. Acidosis also cause hypothermia, increased mortality and reduced survival in neonates. One of the first deleterious effects of intrauterine hypoxia is the expulsion of meconium into the amniotic sac leading to meconium staining of the skin, and in severe cases, meconium aspiration into the lungs. Even though there have been technological changes and improvements in husbandry, piglet mortality due to asphyxia remains a major problem. One potential alternative to reduce neonatal mortality in pigs is the monitoring of fetal stress during birth and the implemention of strategies such as the Apgar score, that is often used in human pediatrics. It is also important to consider the physiological, behavioral and biochemical changes that take place during parturition which subsequently impact the vitality, maturity and development of neonatal pigs. Understanding the pathophysiology of fetal hypoxia should help practitioners and farmers implement more effective delivery techniques aimed at reducing neonatal mortality and improving postnatal performance.

Pulmonary hypertension in the newborn

Pulmonary hypertension of the newborn occurs in 1.9 per 1000 live births and affected infants are hypoxaemic because of right-to-left shunts through the ductus arteriosus and foramen ovale. Pulmonary hypertension of the newborn may be primary, or secondary to a variety of conditions including intrapartum asphyxia, infection, pulmonary hypoplasia, congenital heart disease or drug therapy. It may occur in association with a normal number (maladaptation) or a decreased number of arteries (for example with pulmonary hypoplasia). Few strategies used in infants with pulmonary hypertension of the newborn have been subjected to rigorous evaluation. Inhaled nitric oxide has been shown to reduce the need for extracorporeal membrane oxygenation but not mortality, in term or near term born infants. Preliminary evidence suggests that other vasodilators given by the inhaled route may improve oxygenation and new vasodilators have become available; appropriately designed trials with long-term outcomes are required to test such therapies.

The epidemiology of respiratory failure in neonates born at an estimated gestational age of 34 weeks or more

OBJECTIVE

To prospectively evaluate the primary causes for the use of mechanical ventilation in near-term neonates and to determine the rates of death, chronic lung disease, and neurological complications in these infants.

STUDY DESIGN

We collected data on 1011 neonates who were > or =34 weeks' estimated gestational age; intubated within 72 hours of birth; and expected to require ventilation for more than 6 hours.

RESULTS

The study population had a mean estimated gestational age of 37+/-2 weeks; had a mean birth weight of 2.9+/-0.6 kg; and were predominantly male (62%), white (69%), and delivered by cesarean section (55%). Respiratory distress syndrome (n=437) was the most common pulmonary illness. Chronic lung disease was diagnosed in 109 (11%); neurological complications were reported in 86 (9%); and 51 (5%) patients died.

CONCLUSIONS

Neonates > or =34 weeks who require mechanical ventilation represent a high-risk population who have significant morbidity and mortality.

Cost-effectiveness of inhaled nitric oxide for the management of persistent pulmonary hypertension of the newborn

OBJECTIVE

Inhaled nitric oxide (iNO) is a selective pulmonary vasodilator that has become part of the standard management for persistent pulmonary hypertension of the newborn (PPHN). This treatment modality, like many in neonatology, has not been well studied using quantitative economic techniques. The objective of this study was to evaluate the economic impact of adding iNO to the treatment protocol of PPHN for term infants from birth to the time of discharge from their initial hospitalization.

METHODS

We used decision analysis modeling from a societal perspective to obtain an incremental cost-effectiveness ratio. Outcome probabilities were taken from the medical literature and a cohort of 123 infants who were treated with PPHN at The Children's Hospital of Philadelphia between 1991 and 2002. Costs were estimated from daily resources used by these infants in 2001 dollars. Survival and quality-adjusted life years were used as effectiveness measures. One-way, threshold, and probabilistic sensitivity analyses were performed to assess the robustness of the base-case estimate.

RESULTS

The addition of iNO to the treatment regimen of PPHN increased the cost of treating an infant by an average of 1141 dollars, primarily from an increased number of mechanical ventilation days. Use of iNO led to 3.4% more lives saved and a 6% increase in the average utility gained per infant. The incremental cost-effectiveness ratio was 33,234 dollars per life saved and 19,022 dollars per quality-adjusted life year gained. The model was robust to changes in outcome probabilities, cost, and utility variables. Only 3.6% of the trials using probabilistic sensitivity analysis found iNO to be more expensive with a worse outcome than conventional therapy alone, whereas 35.7% of the trials found iNO to be cheaper and more effective than conventional treatment alone.

CONCLUSIONS

iNO is cost-effective but not cost-saving in treating infants with PPHN from a societal perspective. There are critical time points during an infant's hospitalization that could improve the efficiency and consequently the cost of care for this patient population.

An update on ECMO

Extracorporeal membrane oxygenation (ECMO) is essentially a heart-lung bypass machine that can be used to support certain critically ill neonates. ECMO therapy reached a peak in usage in the mid to late 1980s. At that time, ECMO was most often used for severe complications of persistent pulmonary hypertension, meconium aspiration, congenital diaphragmatic hernia, and sepsis. Since that time, the use of ECMO has decreased, due largely to newer medical advances that have improved the course of these neonates. Whether a nurse works in a Level III ECMO center or a Level I, II, or III NICU, ECMO treatment has become less familiar than it once was. But even though ECMO is used less often, there are times when nothing can take its place. It is important to stay informed so that families of those critically ill newborns who do need ECMO can be educated and supported. This article defines ECMO, discusses when it should be incorporated into the plan of care, describes advances in the NICU that have resulted in the dramatic reduction in the use of ECMO, and provides information and communication strategies to better support the family of a very sick newborn.

Initial dosing of inhaled nitric oxide in infants with hypoxic respiratory failure

BACKGROUND

Inhaled nitric oxide (iNO) is a potent and selective pulmonary vasodilator that decreases pulmonary resistance, and improves ventilation-perfusion matching, thereby improving oxygenation and reducing the need for more invasive therapies. Despite the efficacy of iNO at reducing the use of extracorporeal membrane oxygenation, significant concern remains over the potential toxicity from oxidative derivatives and methemoglobinemia. At present, there is no universal agreement on the lowest effective starting dose. Reported initial doses in the neonatal literature have ranged from 1 to 80 ppm.

PURPOSE

To determine if the initial dose of iNO altered the incidence of adverse outcome.

METHODS

A cohort of neonates who received iNO for treatment of hypoxic respiratory failure and were entered into the Duke Neonatal Nitric Oxide Registry were evaluated. Neonates with congenital anomalies were excluded. This registry collects data from 36 centers that voluntarily report their experiences with iNO. From this database, the starting dose was recorded and the clinical course was followed. Adverse outcomes were prospectively defined and monitored in the database and included: methemoglobinemia, chronic lung disease, treatment with extracorporeal membrane oxygenation, or death.

RESULTS

Data on 476 patients were analyzed. Based on starting doses, records were sorted into three groups: a low-dose group (LDG; <18 ppm, n=57), a mid-dose group (MDG; 18 to 22 ppm, n=320), and a high-dose group (HDG; >22 ppm, n=99). ANOVA showed no statistically significant differences among the groups except for PaO(2)/FiO(2) (p<0.05). Neonates in the high starting dose group were more often classified as treatment failures (21% in the LDG, 27% in the MDG, and 38% in the HDG, p=0.04) and treated with extracorporeal membrane oxygenation (19% in the LDG, 23% in the MDG, and 34% in the HDG, p=0.05) compared to the lower dose groups. In addition, survival without the need for oxygen at 30 days or at discharge was higher in the lower dose groups (93% in the LDG, 84% in the MDG, and 76% in the HDG, p=0.03). Logistic regression, however, showed that the starting dose of iNO did not significantly influence these outcomes when corrected for the degree of hypoxemia (PaO(2)/FiO(2)) at the start of therapy (p>0.1). High initial doses of iNO (>22 ppm) were associated with higher levels of methemoglobin (p< 0.05). There were no differences in mortality or length of hospital stay between the groups.

CONCLUSIONS

There is significant variation in the starting dose of iNO between centers. Our retrospective study shows no evidence that higher doses improve outcome. A low concentration of iNO (<18 ppm) should be considered to minimize the potential toxicity of methemoglobin. Furthermore, a well-designed, prospective trial should be undertaken to further define the optimal starting dose.

Nitric oxide in preterm infant with pulmonary hypoplasia

Premature infants with hypoplastic lungs may have elevated pulmonary vascular resistance with right to left shunt across ductus arteriosus and/or foramen ovale. Inhaled nitric oxide (NO) being selective pulmonary vasodilator without significant effects on systemic circulation can potentially reverse this shunt. The authors herewith report a case of a premature infant with severe hypoxemic respiratory failure after preterm premature prolonged rupture of membranes leading to oligohydramnios and pulmonary hypoplasia that was treated successfully with NO and describe the neurodevelopmental outcome at 1 year of age.

Endothelial nitric oxide synthase (NOS) is upregulated in rapid progressive pulmonary hypertension of the newborn

OBJECTIVE

To provide evidence for the upregulation of endothelial nitric oxide synthase (eNOS) or inducible nitric oxide synthase (iNOS) in the assumed imbalance in the pathophysiology of rapid progressive pulmonary hypertension of the newborn (RPPHN), which is characterized by abnormal hypertrophy of the pulmonary arterioles and arteries leading to increased pulmonary vascular resistance. Furthermore, to determine the cellular source and topographic distribution of eNOS and iNOS.

MATERIAL AND METHODS

Lung biopsies were taken from two term neonates with clinical and echocardiographic evidence of RPPH and of three controls. Biopsies were obtained at an early stage of the disease as well as at post mortem and examined immunohistochemically for the presence of eNOS, iNOS and nitrotyrosine.

RESULTS

The endothelial cells of pulmonary arterioles stained significantly for eNOS protein in RPPHN patients. This was not the case in the control infants. There were no differences for nitrotyrosine or iNOS between RPPHN patients and controls.

CONCLUSION

Rapid progressive pulmonary hypertension of the newborn leads to compensatory induction of eNOS synthesis specifically in endothelial cells of the pulmonary arterioles. This mechanism of compensation can lead to delayed presentation of RPPHN during the late neonatal period. Exogenous inhaled nitric oxide therapy does not lead to suppression of the endogenous synthesis of nitric oxide.

Expanded application of extracorporeal membrane oxygenation in a pediatric surgery practice

OBJECTIVE

To examine the breadth of application and resulting outcomes in a university-based extracorporeal membrane oxygenation (ECMO) program directed by pediatric surgeons.

SUMMARY BACKGROUND DATA

Several randomized control trials have supported the use of ECMO in neonates with respiratory failure. No comparable data exist for older children and young adults who may be afflicted with a variety of uncommon conditions. The indications for ECMO in these patients remain controversial.

METHODS

Patient data were recorded prospectively and reported to the Extracorporeal Life Support Organization. These data were analyzed by indications and outcomes on all patients treated since the inception of the program.

RESULTS

Two hundred sixteen patients were treated with 225 courses of ECMO. Neonates (188 [87%]) outnumbered 28 older patients (aged 6 weeks to 22 years). Overall, 174 patients survived (81%). Sixty-four of 65 (98.5%) neonates with meconium aspiration syndrome survived. ECMO support after heart (3), lung (2), heart-lung (1), and liver (1) transplant yielded a 57% survival to discharge. ECMO also resulted in survival of patients with uncommon conditions, including severe asthma (1), hydrocarbon aspiration (1/2), congestive heart failure due to a cerebral arteriovenous malformation (1), tracheal occlusion incurred during endoscopic stent manipulation (2), meningitis (1), and viral pneumonia (3/5).

CONCLUSIONS

ECMO can potentially eliminate mortality for meconium aspiration syndrome. Survival for other causes of respiratory failure in neonates and older children, while not as dramatic, still surpasses that anticipated with conventional therapy. Moreover, survival of transplant patients has been comparable to that achieved in other children.

Best evidence-based practices: a historic perspective

Neonatologists, neonatal nurses, and others who care for critically ill newborns hope that the care they provide will improve the health and the neurodevelopmental outcome of these neonates. In this progressive era of neonatal medicine, we must pause to look backward even as we look forward, taking full advantage of the opportunity to reflect on our short history and to review several important events in neonatal medicine that have contributed in a meaningful way to the evolution of evidence-based neonatal care. Six interventions highlight why randomized controlled trials are necessary to understand the risks and benefits of our interventions with premature and critically ill infants. We hope this history of the evolving practice of evidence-based neonatal care will enable the reader to have a greater appreciation for the consideration of each and every intervention that we take on behalf of the infants in our care.