Efficacy of porcine versus bovine surfactants for preterm newborns with respiratory distress syndrome: systematic review and meta-analysis

Comparison of Efficacy and Pharmacoeconomic Outcomes Between Calfactant and Poractant Alfa in Preterm Infants With Respiratory Distress Syndrome

OBJECTIVES

In order to evaluate the impact of the surfactant of choice selection, primary end points were to compare the average number of doses per patient, need for mechanical ventilation on day 3, hospital length of stay, and in-hospital mortality between calfactant and poractant alfa in preterm infants with respiratory distress syndrome (RDS). Secondary outcomes included administration complications, development of bronchopulmonary dysplasia (BPD), and estimated average per patient cost among the study population.

METHODS

A retrospective chart review was performed at a level IV neonatal intensive care unit between January 2020 and December 2021 to compare the efficacy, safety, and pharmacoeconomic outcomes -following a surfactant of choice switch from calfactant to poractant alfa in preterm infants with RDS.

RESULTS

Final analysis included 253 premature infants with gestational age (GA) between 22 and 36 weeks who met inclusion criteria. A total of 118 patients who received calfactant required higher average number of doses, 1.5 vs 1.3 doses (p = 0.031), and had more administration complications than 135 patients who received poractant alfa (10.2 vs 2.2%, p = 0.008). The need for redosing, mechanical ventilation on day 3, hospital length of stay, in-hospital mortality, and development of BPD were comparable between both groups. However, the estimated average per patient cost for poractant alfa was 32% higher than calfactant ($1,901 vs $1,439, p <0.001).

CONCLUSIONS

Despite the pharmacoeconomic disadvantage, preterm infants who received poractant alfa needed fewer doses and were less likely to have administration complications compared with those who received calfactant.

Comparing the clinical and economic efficiency of four natural surfactants in treating infants with respiratory distress syndrome

Surfactant therapy has revolutionized the treatment of respiratory distress syndrome (RDS) over the past few decades. Relying on a new method, the current research seeks to compare four common surfactants in the health market of Iran to determine the best surfactant according to the selected criteria. The research was a cross-sectional, retrospective study that used the data of 13,169 infants as recorded on the information system of the Iranian Ministry of Health. To rank the surfactants used, the following indicators were measured: re-dosing rate, average direct treatment cost, average length of stay, disease burden, need for invasive mechanical ventilation, survival at discharge, and medical referrals. The CRITIC (criteria importance through intercriteria correlation) method was used to determine the weight of the indicators, and MABAC (multi-attributive border approximation area comparison) was used to prioritize the surfactants. Based on the seven selected indicators in this research (re-dosing rate, average length of stay, direct medical cost per one prescription, medical referral rate, survival at discharge, disability-adjusted life years, number of newborns in need of invasive mechanical ventilation) and using multi-criteria analysis method, Alveofact was identified as the worst surfactant in infants with either more or less than 32 weeks' gestation. So that some criteria were worse in Alveofact group infants than other groups; for example, in the comparison of the Alveofact group with the average of the total population, it was found that the survival rate at discharge was 57.14% versus 66.43%, and the rate of re-dosing was 1.63 versus 1.39. BLES (bovine lipid extract surfactant) was the best alternative for infants more than 32 weeks' gestation, whereas Survanta was identified as best option for infants with less than 32 weeks' gestation. Curosurf showed an average level of functionality in the ranking. This study advises the policy makers in the field of neonatal health to increase the market share of more effective surfactants based on this study and other similar studies. On the other hand, neonatal health care providers are also advised to prioritize the use of more effective surfactants if possible, depending on the clinical conditions and desired improvements.

Natural Versus Synthetic Surfactant Therapy in Respiratory Distress Syndrome of Prematurity

OBJECTIVES

To compare the clinical efficacy and the cost of treatment between the newborns who received either a natural or a protein-free synthetic surfactant for respiratory distress syndrome (RDS) of prematurity.

METHODS

This is a retrospective analytical study incorporating comparisons of clinical parameters and cost in newborns having RDS of prematurity who received either Survanta (bovine lung extract), a natural surfactant or Surfact (protein-free colfosceril palmitate), a synthetic surfactant.

RESULTS

There were 100 newborns who received either of the natural (n = 52) or synthetic (n = 48) surfactant with mean (SD) gestational age and mean (SD) birth weight of 31.5 (2.6) wk, 1425 (461) g and 32.2 (2.2) wk, 1519 (413) g, respectively. Majority of the newborns (> 90%) received endotracheal surfactant within the first 24 h of life and had similar baseline characteristics in either group. No differences were noted in ventilator settings on admission and 24 h after surfactant/admission. Oxygen requirement, extubation age, complications, hospital stay, and mortality were similar across groups, except that the necrotizing enterocolitis was noted only in natural surfactant group. There was a significant pharmacy cost savings in synthetic surfactant group.

CONCLUSION

Synthetic surfactant was comparable to natural surfactant with regard to outcomes, like ventilator settings, hospital stay, and mortality. Pharmacy cost was less in synthetic surfactant group.

Poractant alfa versus bovine lipid extract surfactant: prospective comparative effectiveness study

OBJECTIVE

To compare short term respiratory outcomes in preterm infants treated with bovine lipid extract surfactant or poractant alfa.

STUDY DESIGN

Prospective comparative effectiveness cohort study of infants <32 weeks' gestational age requiring surfactant in thirteen centers. Each center provided bovine lipid extract surfactant for a set period of time in the year 2019 and then changed to poractant alfa for the remainder of the year. The primary outcome was total duration of respiratory support.

RESULT

968 infants were included. 494 received bovine lipid extract surfactant and 474 received poractant alfa. No difference was observed in the total duration of respiratory support (mechanical ventilation or non-invasive) (median 38 vs 40.5 days), need to re-dose surfactant, bronchopulmonary dysplasia, survival to discharge, or length of admission.

CONCLUSION

In this pragmatic study, we did not identify any difference in short term outcomes between the groups based on the type of surfactant received.

Perinatal care for the extremely preterm infant

Being born preterm (prior to 37 weeks of completed gestation) is a leading cause of childhood death up to five years of age, and is responsible for the demise of around one million preterm infants each year. Rates of prematurity, which range from approximately 5 to 18% of births, are increasing in most countries. Babies born extremely preterm (less than 28 weeks' gestation) and in particular, in the periviable (20^0/7-25^6/7 weeks) period, are at the highest risk of death, or the development of long-term disabilities. The perinatal care of extremely preterm infants and their mothers raises a number of clinical, technical, and ethical challenges. Focusing on 'micropremmies', or those born in the periviable period, this paper provides an update regarding the aetiology and impacts of periviable preterm birth, advances in the antenatal, intrapartum, and acute post-natal management of these infants, and a review of counselling/support approaches for engaging with the infant's family. It concludes with an overview of emerging technology that may assist in improving outcomes for this at-risk population.

Medication Use in the Neonatal Intensive Care Unit and Changes from 2010 to 2018

OBJECTIVE

To provide up-to-date medication prescribing patterns in US neonatal intensive care units (NICUs) and to examine trends in prescribing patterns over time.

STUDY DESIGN

We performed a cohort study of 799 016 infants treated in NICUs managed by the Pediatrix Medical Group from 2010 to 2018. We used 3 different methods to report counts of medication: exposure, courses, and days of use. We defined the change in frequency of medication administration by absolute change and relative change. We examined the Food and Drug Administration (FDA) package insert for each medication to determine whether a medication was labeled for use in infants and used PubMed to search for pharmacokinetics (PK) studies.

RESULTS

The most frequently prescribed medications included ampicillin, gentamicin, caffeine citrate, poractant alfa, morphine, vancomycin, furosemide, fentanyl, midazolam, and acetaminophen. Of the top 50 medications used in infants with extremely low birth weight, only 20 (40%) are FDA-labeled for use in infants; of the 30 that are not labeled for use in infants, 13 (43%) had at least 2 published PK studies. The medications with the greatest relative increase in use from 2010 to 2018 included dexmedetomidine, clonidine, rocuronium, levetiracetam, atropine, and diazoxide. The medications with the greatest relative decrease in use included tromethamine acetate, pancuronium, chloral hydrate, imipenem + cilastatin, and amikacin.

CONCLUSION

Trends of medication use in the NICU change substantially over time. It is imperative to identify changes in medication use in the NICU to better inform further prospective studies.

Surfactant-Assisted Distal Pulmonary Distribution of Budesonide Revealed by Mass Spectrometry Imaging

Direct lung administration of budesonide in combination with surfactant reduces the incidence of bronchopulmonary dysplasia. Although the therapy is currently undergoing clinical development, the lung distribution of budesonide throughout the premature neonatal lung has not yet been investigated. Here, we applied mass spectrometry imaging (MSI) to investigate the surfactant-assisted distal lung distribution of budesonide. Unlabeled budesonide was either delivered using saline as a vehicle (n = 5) or in combination with a standard dose of the porcine surfactant Poractant alfa (n = 5). These lambs were ventilated for one minute, and then the lungs were extracted for MSI analysis. Another group of lambs (n = 5) received the combination of budesonide and Poractant alfa, followed by two hours of mechanical ventilation. MSI enabled the label-free detection and visualization of both budesonide and the essential constituent of Poractant alfa, the porcine surfactant protein C (SP-C). 2D ion intensity images revealed a non-uniform distribution of budesonide with saline, which appeared clustered in clumps. In contrast, the combination therapy showed a more homogeneous distribution of budesonide throughout the sample, with more budesonide distributed towards the lung periphery. We found similar distribution patterns for the SP-C and budesonide in consecutive lung tissue sections, indicating that budesonide was transported across the lungs associated with the exogenous surfactant. After two hours of mechanical ventilation, the budesonide intensity signal in the 2D ion intensity maps dropped dramatically, suggesting a rapid lung clearance and highlighting the relevance of achieving a uniform surfactant-assisted lung distribution of budesonide early after delivery to maximize the anti-inflammatory and maturational effects throughout the lung.

Evaluation of Different Types of Natural Surfactants by Lung Ultrasound in Respiratory Distress Syndrome

OBJECTIVE

This study aimed to compare the lung ultrasonography (LUS) scores after two different natural surfactant administration as a parameter reflecting lung inflation.

STUDY DESIGN

Preterm infants of 32 gestational weeks and below who were diagnosed with respiratory distress syndrome (RDS) were randomly assigned to be administered either poractant alfa or beractant, prospectively. Serial LUS scans were obtained by an experienced neonatologist in a standardized manner before and after (2 and 6 hours) surfactant administration. The LUS scans were evaluated by protocols based on scores and lung profiles.

RESULTS

Thirty-seven infants received poractant alfa and 36 received beractant. The baseline characteristics and presurfactant LUS scores were similar in groups. The scores were significantly decreased after surfactant administration in both groups (2 hours, p = < 0.001; 6 hours, p = < 0.001). LUS scores in poractant group were significantly lower than beractant group when compared at each time point. At the end of 6 hours, the number of infants with the normal profile was significantly higher in the poractant group (∼65%) than the beractant group (22%).

CONCLUSION

LUS is beneficial for evaluating lung aeration after surfactant treatment in preterm infants with RDS. A better lung aeration can be achieved in the early period with the use of poractant alfa.

Surfactant for pulmonary haemorrhage in neonates

BACKGROUND

In the 1960s and 1970s, pulmonary haemorrhage (PH) occurred mainly in full-term infants with pre-existing illness with an incidence of 1.3 per 1000 live births. Risk factors for PH included severity of illness, intrauterine growth restriction, patent ductus arteriosus (PDA), coagulopathy and the need for assisted ventilation. Presently, PH occurs in 3% to 5% of preterm ventilated infants with severe respiratory distress syndrome (RDS) who often have a PDA and have received surfactant. The cause of PH is thought to be due to rapid lowering of intrapulmonary pressure, which facilitates left to right shunting across a PDA and an increase in pulmonary blood flow. Retrospective case reports and one prospective uncontrolled study have shown promising results for surfactant in treating PH.

OBJECTIVES

To evaluate the effect of surfactant treatment compared to placebo or no intervention on mortality and morbidities in neonates with PH.

SEARCH METHODS

For this update The Cochrane Library, Issue 2, 2012; MEDLINE; EMBASE; CINAHL; Clinicaltrials.gov; Controlled-trials.com; proceedings (2000 to 2011) of the Annual Meetings of the Pediatric Academic Societies (Abstracts2View) and Web of Science were searched on 8 February 2012.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that evaluated the effect of surfactant in the treatment of PH in intubated term or preterm (< 37 weeks) neonates with PH. Infants were included up to 44 weeks' postmenstrual age. The interventions studied were intratracheal instillation of surfactant (natural or synthetic, regardless of dose) versus placebo or no intervention.

DATA COLLECTION AND ANALYSIS

If studies were identified by the literature search, the planned analyses included risk ratio, risk difference, number needed to treat to benefit or to harm for dichotomous outcomes, and mean difference for continuous outcomes, with their 95% confidence intervals. A fixed-effect model would be used for meta-analyses. The risk of bias for included trials would be assessed. Heterogeneity tests, including the I2 statistic, would be performed to assess the appropriateness of pooling the data and the results would be reported.

MAIN RESULTS

No trials were identified.

AUTHORS' CONCLUSIONS

No randomised or quasi-randomised trials that evaluated the effect of surfactant in PH were identified. Therefore, no conclusions from such trials can be drawn. In view of the promising results from studies with less strict study designs than a randomised controlled trial, there is reason to conduct further trials of surfactant for the treatment of PH in neonates.

Porcine versus bovine surfactant therapy for RDS in preterm neonates: pragmatic meta-analysis and review of physiopathological plausibility of the effects on extra-pulmonary outcomes

BACKGROUND

While porcine seems to be superior to bovine surfactants in terms of respiratory outcomes, it is unclear if a surfactant can improve extra-pulmonary outcomes in preterm neonates with respiratory distress syndrome and if there is any physiopathological/biological mechanism linking surfactant therapy to these outcomes. We aim to fill these knowledge gaps.

METHODS

Systematic and pragmatic review coupled with meta-analysis of randomized controlled trials of bovine or porcine surfactants administered to treat RDS in preterm neonates; common extra-pulmonary neonatal intensive care outcomes were considered. As additional analysis, animal or human translational studies about mechanisms linking surfactant replacement to extra-pulmonary neonatal outcomes were also systematically reviewed.

RESULTS

Porcine surfactant is associated with lower incidence of patent ductus arteriosus (OR:0.655; 95%CI:0.460-0.931); p = 0.018; 12 trials; 1472 patients); prenatal steroids (coeff.:-0.009, 95%CI:-0.03-0.009, p = 0.323) and gestational age (coeff.:0.079, 95%CI:-0.18-0.34, p = 0.554) did not influence this effect size. No significant differences were found between porcine and bovine surfactants on neonatal intensive care unit length of stay (mean difference (days):-2.977; 95%CI:-6.659-0.705; p = 0.113; 8 trials; 855 patients), intra-ventricular hemorrhage of any grade (OR:0.860; 95%CI:0.648-1.139); p = 0.293; 15 trials; 1703 patients), severe intra-ventricular hemorrhage (OR:0.852; 95%CI:0.624-1.163); p = 0.313; 15 trials; 1672 patients), necrotizing entero-colitis (OR:1.190; 95%CI:0.785-1.803); p = 0.412; 9 trials; 1097 patients) and retinopathy of prematurity (OR:0.801; 95%CI:0.480-1.337); p = 0.396; 10 trials; 962 patients).

CONCLUSIONS

Physiopathological mechanisms explaining the effect of surfactant have been found for patent ductus arteriosus only, while they are lacking for all other endpoints. Porcine surfactant is associated with lower incidence of PDA than bovine surfactants. As there are no differences in terms of other extra-pulmonary outcomes and no physiopathological plausibility, these endpoints should not be used in future trials.

REGISTRATION

PROSPERO n.CRD42018100906.

Biophysical and chemical stability of surfactant/budesonide and the pulmonary distribution following intra-tracheal administration

Intra-tracheal instillation of budesonide using surfactant as a vehicle significantly decreased the incidence of bronchopulmonary dysplasia or death in preterm infants. The formularity of surfactant supplemented with budesonide and biophysical and chemical stability of the suspension has not been well reported. The aims are to investigate the biophysical and chemical stability of two surfactant preparations, Survanta and Curosurf, supplemented with budesonide. Biophysical property of the surface tension of Survanta and Survanta/budesonide suspension and of Curosurf and Curosurf/budesonide suspension was conducted by a pulsating bubble surfactometer and by a drop shape tensiometer. Chemical stability of Survanta/budesonide and of Curosurf/budesonide suspensions was tested by high-performance liquid chromatography analysis (HPLC). Pulmonary distribution of Survanta/¹⁸F-budesonide suspension was examined by a Nano/PET digital scan in rats. The Marangoni effect of Survanta, Curosurf, and budesonide was tested by digital high speed photography. For Survanta supplemented with budesonide, with a concentration ratio of ≥50, the surface tension-lowering activity was minimally affected. Similarly, the surface tension-lowering activity of Curosurf was not significantly affected by addition of budesonide, if the concentration ratio was ≥160. With these concentration ratios of both suspensions, HPLC analysis revealed no new compounds identified. Curosurf as compared to Survanta exhibited a significantly higher Marangoni effect. We conclude that with current dosage recommended for Survanta and Curosurf, both surfactant/budesonide suspensions are biophysically and chemically stable. Both surfactants can act as an effective vehicle for budesonide delivery.

Health Economics and Outcomes of Surfactant Treatments for Respiratory Distress Syndrome Among Preterm Infants in US Level III/IV Neonatal Intensive Care Units

OBJECTIVE

To compare length of stay (LOS), costs, mechanical ventilation (MV), and mortality in preterm infants treated in the Neonatal Intensive Care Unit (NICU) with beractant (BE), calfactant (CA), and poractant alfa (PA) for Respiratory Distress Syndrome (RDS).

METHODS

This study evaluated preterm infants born between 2010 and 2013 with RDS diagnosis, gestational age of 25 to 36 weeks, birthweight of ≥500 g, and age of ≤2 days on first surfactant administration. Multivariable regression was used to evaluate all NICU outcomes.

RESULTS

Of 13,240 infants meeting the study criteria, 4136 (31.2%) received BE, 2502 (18.9%) received CA, and 6602 (49.9%) received PA. Adjusted analyses estimated similar mean LOS (BE 26.7 days, CA 27.8 days, and PA 26.2 days) and hospital costs (BE: $50,929; CA: $50,785; and PA: $50,212). Compared to PA, BE and CA were associated with greater odds of MV use on day 3 (OR = 1.56 and 1.60, respectively) and day 7 (OR = 1.39 and 1.28, respectively; all p < 0.05). Adjusted NICU mortality was significantly higher only with CA vs PA (OR = 1.51; p = 0.015).

CONCLUSION

Adjusted NICU LOS and costs were similar among BE, CA, and PA. Infants receiving PA were less likely to be on MV at 3 and 7 days, and PA treatment was associated with lower odds of NICU mortality when compared to CA.

Surfactant preparations for preterm infants with respiratory distress syndrome: past, present, and future

Following the first successful trial of surfactant replacement therapy for preterm infants with respiratory distress syndrome (RDS) by Fujiwara in 1980, several animal-derived natural surfactants and synthetic surfactants have been developed. Synthetic surfactants were designed to overcome limitations of natural surfactants such as cost, immune reactions, and infections elicited by animal proteins contained in natural surfactants. However, first-generation synthetic surfactants that are protein-free have failed to prove their superiority over natural surfactants because they lack surfactant protein (SP). Lucinactant, a second-generation synthetic surfactant containing the SP-B analog, was better or at least as effective as the natural surfactant, suggesting that lucinactant could act an alternative to natural surfactants. Lucinactant was approved by the U. S. Food and Drug Administration in March 2012 as the fifth surfactant to treat neonatal RDS. CHF5633, a second-generation synthetic surfactant containing SP-B and SP-C analogs, was effective and safe in a human multicenter cohort study for preterm infants. Many comparative studies of natural surfactants used worldwide have reported different efficacies for different preparations. However, these differences are believed to due to site variations, not actual differences. The more important thing than the composition of the surfactant in improving outcome is the timing and mode of administration of the surfactant. Novel synthetic surfactants containing synthetic phospholipid incorporated with SP-B and SP-C analogs will potentially represent alternatives to natural surfactants in the future, while improvement of treatment modalities with less-invasive or noninvasive methods of surfactant administration will be the most important task to be resolved.

Porcine vs bovine surfactant therapy for preterm neonates with RDS: systematic review with biological plausibility and pragmatic meta-analysis of respiratory outcomes

Background

Bovine surfactants are known to be clinically equivalent but it is unclear if porcine or bovine surfactants at their licensed dose should be preferred to treat respiratory distress syndrome in preterm neonates.

Methods

We performed a comprehensive review of biochemical and pharmacological features of surfactants to understand the biological plausibility of any clinical effect. We then performed a pragmatic meta-analysis comparing internationally marketed porcine and bovine surfactants for mortality and respiratory outcomes. Search for randomised controlled trials with no language/year restrictions and excluding “grey” literature, unpublished or non-peer reviewed reports was conducted, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and the most recent methodological recommendations.

Results

Sixteen articles were included in the review and 14 in the meta-analysis (1491 neonates). 200 mg/kg poractant-α (a porcine surfactant) was associated with lower BPD/mortality (OR 0.632[95%CI:0.494, 0.809];p < 0.001),BPD (OR 0.688[95%CI:0.512, 0.925];p = 0.013), retreatment (OR 0.313[95%CI:0.187, 0.522];p < 0.0001), airleaks (OR 0.505[95%CI:0.308, 0.827];p = 0.006) and lung haemorrhage (OR 0.624[95%CI:0.388, 1];p = 0.051). Gestational age is associated with effect size for BPD (coefficient: 0.308 [95%CI:0.063, 0.554];p = 0.014) and surfactant retreatment (coefficient: -0.311 [95%CI:-0.595, − 0.028];p = 0.031).

Conclusion

200 mg/kg poractant-α is associated with better respiratory outcomes compared to bovine surfactants at their licensed dose. The effect of poractant-α on BPD and surfactant retreatment is greater at lowest and highest gestational ages, respectively.

Trial registration

PROSPERO n.42017075251.

Electronic supplementary material

The online version of this article (10.1186/s12931-019-0979-0) contains supplementary material, which is available to authorized users.

Poractant Alfa Versus Beractant for Neonatal Respiratory Distress Syndrome: A Retrospective Cost Analysis

OBJECTIVES The objectives of this study were to determine the average medication cost per patient of poractant alfa and beractant, and to compare the outcomes of treatment with these agents.

METHODS We conducted a retrospective, observational, cohort study of patients who received surfactant, before and after an institutional formulary change from beractant to poractant alfa. The primary outcome was the average medication cost per case. Secondary measures were clinical outcomes, including duration of respiratory support, length of hospital stay, and the occurrence of complications.

RESULTS A total of 114 patients were enrolled; 38 were treated with poractant alfa and 76 patients were treated with beractant. Baseline characteristics were similar between groups. The average medication cost per patient was $1756.44 ± $1030.06 and $1329.78 ± $705.64 for poractant alfa and beractant, respectively (p = 0.011). Patients treated with poractant alfa had a shorter length of stay (45.0 ± 30.5 days) than patients treated with beractant (65.1 ± 37.1 days) (p = 0.010). Rates of pneumothoraces, pulmonary hemorrhage, necrotizing enterocolitis, intraventricular hemorrhage, and mortality did not differ significantly between groups.

CONCLUSIONS We found an unanticipated increase in drug cost with poractant alfa compared to beractant.

Settling for second best: when should doctors agree to parental demands for suboptimal medical treatment?

BACKGROUND

Doctors sometimes encounter parents who object to prescribed treatment for their children, and request suboptimal substitutes be administered instead (suboptimal being defined as less effective and/or more expensive). Previous studies have focused on parental refusal of treatment and when this should be permitted, but the ethics of requests for suboptimal treatment has not been explored.

METHODS

The paper consists of two parts: an empirical analysis and an ethical analysis. We performed an online survey with a sample of the general public to assess respondents' thresholds for acceptable harm and expense resulting from parental choice, and the role that religion played in their judgement. We also identified and applied existing ethical frameworks to the case described in the survey to compare theoretical and empirical results.

RESULTS

Two hundred and forty-two Mechanical Turk workers took our survey and there were 178 valid responses (73.6%). Respondents' agreement to provide treatment decreased as the risk or cost of the requested substitute increased (p<0.001). More than 50% of participants were prepared to provide treatment that would involve a small absolute increased risk of death for the child (<5%) and a cost increase of US$<500, respectively. Religiously motivated requests were significantly more likely to be allowed (p<0.001). Existing ethical frameworks largely yielded ambiguous results for the case. There were clear inconsistencies between the theoretical and empirical results.

CONCLUSION

Drawing on both survey results and ethical analysis, we propose a potential model and thresholds for deciding about the permissibility of suboptimal treatment requests.

Cerebral and lung effects of a new generation synthetic surfactant with SP-B and SP-C analogs in preterm lambs

BACKGROUND

Though natural surfactants (SF) are clinically superior to protein-free synthetic preparations, CHF-5633, a synthetic SF containing SP-B and SP-C analog peptides is a potential alternative to natural SF for treating neonatal respiratory distress syndrome (RDS). Nevertheless, information is lacking regarding the safety of this new treatment for the neonatal brain. We sought to compare the cerebral and pulmonary effects of this new synthetic surfactant (CHF5633) with those of natural porcine surfactant (Cursosurf) in premature lambs with RDS.

METHODS

Twenty-one preterm lambs were randomly assigned to receive CHF5633, Curosurf, or no treatment (control). Pulmonary (gas exchange, lung mechanics) and cerebral (carotid artery blood flow, cerebral oxygen metabolism) effects were measured every 30 min for 6 h. Pulmonary and cerebral histological analysis were also performed.

RESULTS

After delivery, lambs developed severe RDS (F_IO2 :1, pH < 7.15, P_aCO2  > 70 mmHg, P_aO2  < 40 mmHg, C_dyn  < 0.1 mL/cmH₂ O/kg). By 30 min after treatment, animals in both SF-treated groups had consistently better gas exchange and lung mechanics than controls. After CHF5633 administration, P_aCO2 , carotid artery blood flow, and cerebral oxygen delivery tended to slowly decrease compared to other groups. By 2 h, SF-treated groups had similar values of all parameters studied, these remaining steady for the rest of the experiment. Lambs administered CHF5633 obtained better lung and brain injury scores than controls.

CONCLUSION

Intratracheal administration of a bolus of CHF5633 improves pulmonary status in preterm lambs with severe RDS, obtaining better lung and brain injury scores than controls and favorable cerebral hemodynamics, comparable to those with gold standard Curosurf treatment.

Poractant alfa versus bovine lipid extract surfactant for infants 24+0 to 31+6 weeks gestational age: A randomized controlled trial

Objectives

To compare the efficacy and safety of poractant alfa and bovine lipid extract surfactant in preterm infants.

Study design

Randomized, partially-blinded, multicenter trial. Infants <32 weeks needing surfactant before 48 hours were randomly assigned to receive poractant alfa or bovine lipid extract surfactant. The primary outcome was being alive and extubated at 48 hours post-randomization. Secondary outcomes included need for re-dosing, duration of respiratory support and oxygen, bronchopulmonary dysplasia, mortality and complications during administration.

Results

Three centers recruited 87 infants (mean 26.7 weeks and 906 grams) at a mean age of 5.9 hours, between March 2013 and December 2015. 21/42 (50%) were alive and extubated at 48 hours in the poractant alfa group vs 26/45 (57.8%) in the bovine lipid extract surfactant group; adjusted OR 0.76 (95% CI 0.30–1.93) (p = 0.56). No differences were observed in the need to re-dose. Duration of oxygen support (41.5 vs 62 days; adjusted OR 1.69 95% CI 1.02–2.80; p = 0.04) was reduced in infants who received poractant alfa. We observed a trend in bronchopulmonary dysplasia among survivors (51.5% vs 72.1%; adjusted OR 0.35 95%CI 0.12–1.04; p = 0.06) favoring poractant alfa. Twelve infants died before discharge, 9 in the poractant alfa group and 3 in the bovine lung extract group. Severe airway obstruction following administration was observed in 0 (poractant alfa) and 5 (bovine lipid extract surfactant) infants (adjusted OR 0.09 95%CI <0.01–1.27; p = 0.07).

Conclusion

No statistically significant difference was observed in the proportion of infants alive and extubated within 48h between the two study groups. Poractant alfa may be more beneficial and associated with fewer complications than bovine lipid extract surfactant. However, we observed a trend towards higher mortality in the poractant alfa group. Larger studies are needed to determine whether observed possible benefits translate in shorter hospital admissions, or other long term benefits and determine whether there is a difference in mortality.

Evolution of surfactant therapy for respiratory distress syndrome: past, present, and future

Respiratory distress syndrome (RDS) due to surfactant deficiency is the most common cause of respiratory failure in preterm infants. Tremendous progress has been made since the original description that surfactant deficiency is the major cause of RDS. Surfactant therapy has been extensively studied in preterm infants and has been shown to significantly decrease air leaks and neonatal and infant mortality. Synthetic and animal-derived surfactants from bovine as well as porcine origin have been evaluated in randomized controlled trials. Animal-derived surfactants generally result in faster weaning of respiratory support, shorter duration of invasive ventilation, and decreased mortality when compared to first- or second-generation of synthetic surfactants, but some of the second-generation synthetic surfactants are at least not inferior to the animal-derived surfactants. Using a higher initial dose of porcine derived surfactant may provide better outcomes when compared with using lower doses of bovine surfactants, likely, due to compositional difference and/or the dose. Third-generation synthetic surfactant containing peptide analogs of surfactant protein B and C are currently being studied. Less invasive intra-tracheal surfactant administration techniques in spontaneously breathing neonate receiving noninvasive ventilator support are also being evaluated. In the present era, prophylactic surfactant is not recommended as it may increase the risk of lung injury or death. In the future, surfactants may be used as vector to deliver steroids, or used in combination with molecules, such as, recombinant Club Cell Protein-10 (rhCC-10) to improve pulmonary outcomes. Also, noninvasive surfactant administration techniques, such as aerosolization or atomization of surfactant may play a greater role in the future.

Surfactant for Respiratory Distress Syndrome: New Ideas on a Familiar Drug with Innovative Applications

In the last 4 decades, advances in neonatology have led to a significant increase in the survival of preterm infants. One of the biggest advances was the introduction of surfactant replacement therapy for the treatment of respiratory distress syndrome. This is the main cause of respiratory insufficiency in preterm infants and is one of the major causes of perinatal morbidity and mortality. Surfactant replacement therapy is already a well-investigated and established therapy in neonatology. However, surfactant replacement therapy has progressed and been refined over recent decades, especially with the increasing care for preterm infants born before 26 weeks' gestational age and the recent clinical focus on avoiding mechanical ventilation. Clinical evidence is evolving on new types of surfactant, surfactant dosages, co-medication given before, with, or after surfactant replacement, and new technical advances regarding the mode of administration.

In Vivo Evaluation of the Acute Pulmonary Response to Poractant Alfa and Bovactant Treatments in Lung-Lavaged Adult Rabbits and in Preterm Lambs with Respiratory Distress Syndrome

BACKGROUND

Poractant alfa (Curosurf^®) and Bovactant (Alveofact^®) are two animal-derived pulmonary surfactants preparations approved for the treatment of neonatal respiratory distress syndrome (nRDS). They differ in their source, composition, pharmaceutical form, and clinical dose. How much these differences affect the acute pulmonary response to treatment is unknown.

OBJECTIVES

Comparing these two surfactant preparations in two different animal models of respiratory distress focusing on the short-term response to treatment.

METHODS

Poractant alfa and Bovactant were administered in a 50-200 mg/kg dose range to surfactant-depleted adult rabbits with acute respiratory distress syndrome induced by lavage and to preterm lambs (127-129 days gestational age) with nRDS induced by developmental immaturity. The acute impact of surfactant therapy on gas exchange and pulmonary mechanics was assessed for 1 h in surfactant-depleted rabbits and for 3 h in preterm lambs.

RESULTS

Overall, treatment with Bovactant 50 mg/kg or Poractant alfa 50 mg/kg did not achieve full recovery of the rabbits' respiratory conditions, as indicated by significantly lower arterial oxygenation and carbon dioxide values. By contrast, the two approved doses for clinical use of Poractant alfa (100 and 200 mg/kg) achieved a rapid and sustained recovery in both animal models. The comparison of the ventilation indices of the licensed doses of Bovactant (50 mg/kg) and Poractant alfa (100 mg/kg) showed a superior performance of the latter preparation in both animal models. At equal phospholipid doses, Poractant alfa was superior to Bovactant in terms of arterial oxygenation in both animal models. In preterm lambs, surfactant replacement therapy with Poractant alfa at either 100 or 200 mg/kg was associated with significantly higher lung gas volumes compared to Bovactant treatment with 100 mg/kg.

CONCLUSION

At the licensed doses, the acute pulmonary response to Poractant alfa was significantly better than the one observed after Bovactant treatment, either at 50 or at 100 mg/kg dose, in two animal models of pulmonary failure.

Metabolic Functions of the Lung, Disorders and Associated Pathologies

The primary function of the lungs is gas exchange. Approximately 400 million years ago, the Earth's atmosphere gained enough oxygen in the gas phase for the animals that emerged from the sea to breathe air. The first lungs were merely primitive air sacs with a few vessels in the walls that served as accessory organs of gas exchange to supplement the gills. Eons later, as animals grew accustomed to a solely terrestrial life, the lungs became highly compartmentalized to provide the vast air-blood surface necessary for O2 uptake and CO2 elimination, and a respiratory control system was developed to regulate breathing in accordance with metabolic demands and other needs. With the evolution and phylogenetic development, lungs were taking a variety of other specialized functions to maintain homeostasis, which we will call the non-respiratory functions of the lung and that often, and by mistake, are believed to have little or no connection with the replacement gas. In this review, we focus on the metabolic functions of the lung, perhaps the least known, and mainly, in the lipid metabolism and blood-adult lung vascular endothelium interaction. When these functions are altered, respiratory disorders or diseases appear, which are discussed concisely, emphasizing how they impact the most important function of the lungs: external respiration.

Comparison of the Efficacy of Three Natural Surfactants (Curosurf, Survanta, and Alveofact) in the Treatment of Respiratory Distress Syndrome Among Neonates: A Randomized Controlled Trial

BACKGROUND

Although several different types of natural surfactants are available, including Alveofact, Curosurf, and Survanta, the preferred type and the magnitude of their effects are unknown.

OBJECTIVES

This study was designed to compare the effects of these three surfactants on the gas exchange and clinical outcomes of neonates with respiratory distress syndrome (RDS).

METHODS

This triple-blind randomized clinical trial studied all preterm neonates ≤ 37 weeks with RDS who were admitted to the neonatal intensive care unit (NICU) of Taleghani hospital (Tabriz, Iran) between 2012 and 2013. The patients were divided into three groups, each of which received one of these surfactants. The incidences of ventilator dependency, patent ductus arteriosus (PDA), broncho-pulmonary dysplasia (BPD), retinopathy of prematurity (ROP), intraventricular hemorrhage (IVH), hospital-stay length, and continuous positive airway pressure (CPAP) failure, as well as blood gas levels, were recorded as endpoint measurements and compared.

RESULTS

In total, 165 neonates of gestational age ≤ 37 weeks with RDS were examined. Neonates were allocated to three different groups randomly, including a Survanta group (n = 49), a Curosurf group (n = 62), and an Alveofact group (n = 54). The mean gestational age of the neonates was 31.6 ± 3.7 weeks, and their mean weight was 1,840 ± 790 grams. The male/female ratio was 2:1 (67% male, 33% female); 104 (63%) neonates were ≤ 32 weeks gestational age, and 61 (37%) were >32 weeks. There were no significant differences for gender or demographic characteristics among the neonates in relation to the type of applied surfactant. According to the clinical parameters (BPD, IVH, ROP, hospital-stay length, and mechanical ventilation requirement), no significant differences were observed between the groups before and after surfactant administration, but the differences between the Survanta and Alveofact groups for the incidence rates of pneumothorax (P = 0.03) and pulmonary hemorrhage (P = 0.03) were statistically significant.

CONCLUSIONS

No significant differences were observed in most of the clinical variables between the three types of natural surfactant, but in neonates ≤ 32 weeks, the incidence of pneumothorax was significantly higher in the Alveofact group; in neonates > 32 weeks, the incidences of PDA, mean hospital-stay length, and mean mechanical ventilation time were also significantly higher in the same group. It thus appears that Curosurf and Survanta replacement therapies among premature neonates with RDS perform better than Alveofact replacement therapy.

Comparison of animal-derived surfactants for the prevention and treatment of respiratory distress syndrome in preterm infants

BACKGROUND

Animal-derived surfactants have been shown to have several advantages over the first generation synthetic surfactants and are the most commonly used surfactant preparations. The animal-derived surfactants in clinical use are minced or lavaged and modified or purified from bovine or porcine lungs. It is unclear whether significant differences in clinical outcome exist among the available bovine (modified minced or lavage) and porcine (minced or lavage) surfactant extracts.

OBJECTIVES

To compare the effect of administration of different animal-derived surfactant extracts on the risk of mortality, chronic lung disease, and other morbidities associated with prematurity in preterm infants at risk for or having respiratory distress syndrome (RDS).

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 7), MEDLINE via PubMed (1966 to July 31, 2015), EMBASE (1980 to July 31, 2015), and CINAHL (1982 to July 31, 2015). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomized controlled trials and quasi-randomized trials.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials that compared the effect of animal-derived surfactant extract treatment administered to preterm infants at risk for or having RDS to prevent complications of prematurity and mortality.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes were excerpted from the reports of the clinical trials by the review authors. Subgroup analyses were performed based on gestational age, surfactant dosing and schedule, treatment severity and treatment strategy. Data analysis was performed in accordance with the standards of the Cochrane Neonatal Review Group.

MAIN RESULTS

Sixteen randomized controlled trials were included in the analysis. Bovine lung lavage surfactant extract to modified bovine minced lung surfactant extract: Seven treatment studies and two prevention studies compared bovine lung lavage surfactant extract to modified bovine minced lung surfactant extract. The meta-analysis did not demonstrate any significant differences in death or chronic lung disease in the prevention trials (typical RR 1.02, 95% CI 0.89 to 1.17; typical RD 0.01, 95% CI -0.05 to 0.06; 2 studies and 1123 infants; high quality evidence) or treatment trials (typical RR 0.95, 95% CI 0.86 to 1.06; typical RD -0.02 , 95% CI -0.06 to 0.02; 3 studies and 2009 infants; high quality evidence) Modified bovine minced lung surfactant extract compared with porcine minced lung surfactant extract: Nine treatment studies compared modified bovine minced lung surfactant extract to porcine minced lung surfactant extract. Meta-analysis of these trials demonstrate a significant increase in the risk of mortality prior to hospital discharge (typical RR 1.44, 95% CI 1.04 to 2.00; typical RD 0.05, 95% CI 0.01 to 0.10; NNTH 20, 95% CI 10 to 100; 9 studies and 901 infants; moderate quality evidence), death or oxygen requirement at 36 weeks' postmenstrual age (typical RR 1.30, 95% CI 1.04 to 1.64; typical RD 0.11, 95% CI 0.02 to 0.20; NNTH 9, 95% CI 5 to 50; 3 studies and 448 infants; moderate quality evidence), receiving more than one dose of surfactant (typical RR 1.57, 95% CI 1.29 to 1.92; typical RD 0.14, 95% CI 0.08 to 0.20; NNTH 7, 95% CI 5 to 13; 6 studies and 786 infants), and patent ductus arteriosus (PDA) requiring treatment (typical RR 1.86, 95% CI 1.28 to 2.70; typical RD 0.28, 95% CI 0.13 to 0.43; NNTH 4, 95% CI 2 to 8; 3 studies and 137 infants) in infants treated with modified bovine minced lung surfactant extract compared with porcine minced lung surfactant extract. In the subgroup analysis based on initial dose of surfactant, improvement in mortality prior to discharge (typical RR 1.62, 95% CI 1.11 to 2.38; typical RD 0.06, 95% CI 0.01 to 0.11; NNTH 16, 95% CI 9 to 100) and risk of death or oxygen requirement at 36 weeks' postmenstrual age (typical RR 1.39, 95% CI 1.08 to 1.79; typical RD 0.13, 95% 0.03 to 0.23; NNTH 7, 95% CI 4 to 33) was limited to higher initial dose of porcine minced lung surfactant (> 100 mg/kg). Other comparisons: No difference in outcome was noted between bovine lung lavage surfactant extract versus porcine minced lung surfactant extract. There were no studies comparing bovine lung lavage surfactant extract versus porcine lung lavage surfactant; or porcine minced lung surfactant extract versus porcine lung lavage surfactant.

AUTHORS' CONCLUSIONS

Significant differences in clinical outcome were noted in the comparison trials of modified minced lung surfactant extract (beractant) compared with porcine minced lung surfactant extract (poractant alfa) including a significant increase in the risk of mortality prior to discharge, death or oxygen requirement at 36 weeks' postmenstrual age, PDA requiring treatment and "receiving > 1 dose of surfactant" in infants treated with modified bovine minced lung surfactant extract compared with porcine minced lung surfactant extract. The difference in these outcomes was limited to studies using a higher initial dose of porcine minced lung surfactant extract. It is uncertain whether the observed differences are from differences in dose or from source of extraction (porcine vs. bovine) because of the lack of dose-equivalent comparison groups with appropriate sample size. No differences in clinical outcomes were observed in comparative trials between bovine lung lavage surfactant and modified bovine minced lung surfactants.

Efficacy of surfactant-TA, calfactant and poractant alfa for preterm infants with respiratory distress syndrome: a retrospective study

PURPOSE

To compare the efficacy of the new drug calfactant with the commonly used drugs surfactant-TA and poractant alfa.

MATERIALS AND METHODS

A total of 332 preterm infants at 24-31 weeks' gestation with respiratory distress syndrome (RDS) were enrolled and allocated to three groups according to the surfactant instilled; Group 1 (n=146, surfactant-TA), Group 2 (n=96, calfactant), and Group 3 (n=90, poractant alfa). The diagnosis of RDS and the decision to replace the pulmonary surfactant were left to the attending physician and based on patient severity determined by chest radiography and blood gas analysis. Data were collected and reviewed retrospectively using patient medical records.

RESULTS

Demographic factors including gestational age, birth weight, Apgar score, clinical risk index for babies II score, and maternal status before delivery were not different between the study groups. Instances of surfactant redosing and pulmonary air leaks, as well as duration of mechanical ventilation, were also not different. Rates of patent ductus arteriosus, intraventricular hemorrhage (≥grade III), periventricular leukomalacia, high stage retinopathy of prematurity, necrotizing enterocolitis (≥stage II), and mortality were also similar, as was duration of hospital stay. Cases of pulmonary hemorrhage and moderate to severe bronchopulmonary dysplasia were increased in Group 3.

CONCLUSION

Calfactant is equally as effective as surfactant-TA and poractant alfa. This was the first study comparing the efficacy of surfactant-TA, calfactant, and poractant alfa in a large number of preterm infants in Korea. Further randomized prospective studies on these surfactants are needed.

A unique story in neonatal research: the development of a porcine surfactant

Surfactant deficiency was identified as the cause of respiratory distress syndrome (RDS) as long ago as 1959. Trials of surfactant replacement in the 1960s were unsuccessful because the preparations used contained only phospholipids and they were administered inefficiently by nebulization. In the 1970s Bengt Robertson and Göran Enhörning showed that natural surfactant, containing both phospholipids and proteins, could ameliorate the signs of RDS in immature rabbits. In the 1980s Bengt Robertson and Tore Curstedt developed a porcine surfactant, Curosurf (named after their surnames), which was effective in immature animals and was used in a pilot clinical trial beginning in 1983. Subsequent randomized clinical trials were planned a year later by Bengt Robertson, Tore Curstedt and Henry Halliday, and the first trial was begun in 1985. This showed that Curosurf reduced pulmonary air leaks and neonatal mortality in preterm infants with severe RDS. A second trial, coordinated by Christian Speer, demonstrated that multiple doses of Curosurf were more effective than a single dose. Subsequent trials conducted by the Collaborative European Multicenter Study Group, which included among others Guilio Bevilacqua, Janna Koppe, Ola Saugstad, Nils Svenningsen and Jean-Pierre Relier, showed that early treatment was more effective than later administration and that infants treated at birth had similar neurodevelopmental status to untreated controls at a corrected age of 2 years. Members of the Collaborative European Multicenter Study Group in Denmark and Sweden performed studies to demonstrate the benefits of a combination of surfactant treatment and early continuous positive airway pressure. Curosurf has also been compared with several synthetic and natural surfactants, and at a dose of 200 mg/kg Curosurf has been shown to be superior to either Survanta or Curosurf used at a dose of 100 mg/kg. Recently, new-generation synthetic surfactants containing both phospholipids and proteins have been developed. After preclinical testing, CHF5633 (developed by Tore Curstedt and Jan Johansson in collaboration with Chiesi Farmaceutici) has undergone a preliminary first study in humans under the guidance of Christian Speer. If effective, this new surfactant preparation could revolutionize the treatment of preterm infants worldwide as it could be made consistently and safely in almost unlimited quantities. This story of a porcine surfactant preparation has been truly remarkable, and many thousands of preterm babies worldwide are now alive and well because of it.

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.

Adjunctive treatments in pediatric acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a devastating process that involves pulmonary inflammation, alveolar damage and hypoxemic respiratory failure. Although advances in management approaches over the past two decades have resulted in significantly improved outcomes, death from pediatric ARDS may still occur in up to 35% of patients. While invasive mechanical ventilation is an essential component of ARDS management, various adjuncts have been utilized as treatment for these patients. However, evidence-based data in infants and children in this area are lacking. In this article, the authors review the available evidence supporting (or not supporting) the use of non-ventilatory adjunctive strategies in the management of pediatric ARDS, including prone positioning, pulmonary vasodilators, β-agonists, steroids and surfactant.

The role of surfactant and non-invasive mechanical ventilation in early management of respiratory distress syndrome in premature infants

BACKGROUND

Surfactant replacement therapy has been used for few decades for the treatment of respiratory distress syndrome (RDS) and has significantly improved morbidity and mortality in premature infants. Non-invasive respiratory support has recently emerged as a strategy in the early management of RDS. In this review, we discuss the different strategies of early management of RDS.

DATA SOURCES

A literature search of PubMed database was conducted to review the subject. The quality of evidence of key clinical studies was graded according to a modified grading system of the international GRADE group.

RESULTS

Continuous positive airway pressure (CPAP) with selective surfactant is a safe alternative to routine intubation, surfactant and mechanical ventilation in preterm infants with spontaneous breathing, and such an approach has been associated with decreased risk of death and bronchopulmonary dysplasia. There is a risk of pneumothorax when using a high pressure of CPAP (≥8 cm of H2O), a high partial pressure of carbon dioxide (PCO2 >75 mm of Hg), and a high fraction of inspired oxygen (FiO2 >0.6) as a threshold for intubation while on CPAP.

CONCLUSION

Not all preterm infants need surfactant treatment, and non-invasive respiratory support is a safe and effective approach.

The use of surfactant in the neonatal period- the known aspects, those still under research and those which need to be investigated further

Respiratory distress syndrome is pulmoner insufficiency caused by the lack of surfactant and the main reason of morbidity and mortality in preterm infants. Mothers at high risk of preterm birth should be transferred to perinatal centers with experience for respiratory distress syndrome and ante-natal steroids should be given before 35 weeks' of gestational age. Surfactant treatment should be applied to babies with or at high risk for respiratory distress syndrome. Prophylaxis should be given to infants of <26 weeks of gestational age and to infants requiring entubation in the delivery room. Nasal continuous positive airway pressure should be considered in infants with complete steroid treatment and without entubation need. Early surfactant may be given if entubation is performed during follow-up. Natural forms of surfactant should be preferred when needed. If the infant is stable, early extubation and non-invasive respiratory support should be considered. In this review, the recent studies' current data about surfactant treatment will be discussed.

Poractant alfa versus beractant for respiratory distress syndrome in preterm infants: a retrospective cohort study

AIM

Poractant alfa and beractant are the commonly used animal derived surfactants in preterm infants with respiratory distress syndrome. Between 2005 and 2007, poractant alfa and beractant were alternated every month in our neonatal intensive care unit for 27 months. The aim of this study was to compare the outcomes of preterm infants who received poractant alfa versus beractant.

METHOD

Single-centre, retrospective cohort study of inborn preterm infants <32 weeks gestation (23-31(+6) ).

RESULTS

Six hundred sixty-four preterm infants (<32 weeks) were born during the study period, of which 415 received surfactant (poractant alfa: 214; beractant: 201). Infants in the poractant alfa group were 2.8 days younger than beractant (27.0 ± 2.3 vs. 27.4 ± 2.3 weeks; P = 0.03). All other baseline characters including Clinical Risk Index for Babies II scores were similar for both groups. No significant differences were found for the following outcomes: death or chronic lung disease (78/212 vs. 59/200; P = 0.28); death (24/214 vs. 15/201, P = 0.24); moderate to severe chronic lung disease (63/212 vs. 46/200; P = 0.45) and moderate to severe disability (20/163 vs. 19/151, P = 0.98) between poractant alfa and beractant, respectively.

CONCLUSIONS

The results of our study do not support the need for preferential use of poractant alfa or beractant.

Comparative effectiveness of surfactant preparations in premature infants

OBJECTIVE

To compare effectiveness of 3 surfactant preparations (beractant, calfactant, and poractant alfa) in premature infants for preventing 3 outcomes: (1) air leak syndromes; (2) death; and (3) bronchopulmonary dysplasia (BPD) or death (composite outcome).

STUDY DESIGN

We conducted a comparative effectiveness study of premature infants admitted to 322 neonatal intensive care units in the US from 2005-2010 who were treated with beractant, calfactant, or poractant alfa. We compared the incidence of air leak syndromes, death, and BPD or death, adjusting for gestational age (GA), antenatal steroids, discharge year, and small for GA status.

RESULTS

A total of 51282 infants received surfactant; 40% received beractant, 30% calfactant, and 30% poractant alfa. Median birth weight was 1435 g (IQR 966-2065); median GA was 30 weeks (27-33). On adjusted analysis, we observed a similar risk of air leak syndromes (calfactant vs beractant OR = 1.17 [95% CI: 0.95, 1.43]; calfactant vs poractant OR = 1.23 [0.98, 1.56]; beractant vs poractant OR = 1.06 [0.87, 1.29]), death (calfactant vs beractant OR = 1.14 [0.93, 1.39]; calfactant vs poractant OR = 0.98 [0.78, 1.23]; beractant vs poractant OR = 0.86 [0.72, 1.04]), and BPD or death (calfactant vs beractant OR = 1.08 [0.93, 1.26]; calfactant vs poractant OR = 1.19 [1.00, 1.41]; beractant vs poractant OR = 1.10 [0.96, 1.27]).

CONCLUSIONS

Beractant, calfactant, and poractant alfa demonstrated similar effectiveness in prevention of air leak syndromes, death, and BPD or death in premature infants when adjusted for site. Previously described differences in mortality between surfactants likely do not represent true differences in effectiveness but may relate to site variation in outcomes.

The preterm lung and airway: past, present, and future

The tremendous advancement that has occurred in neonatal intensive care over the last 40-50 years can be largely attributed to greater understanding of developmental pathobiology in the newborn lung. Nonetheless, this improved survival from respiratory distress syndrome has been associated with continuing longer-term morbidity in the form of bronchopulmonary dysplasia (BPD). As a result, neonatal lung injury is a renewed focus of scientific interest. The onset of such an injury may begin in the delivery room, and this has generated interest in minimizing oxygen therapy and aggressive ventilatory support during the transition from fetal to neonatal lung. Fortunately, antenatal steroid therapy and selective use of surfactant therapy are now widely practiced, although fine tuning of this therapy for selected populations is ongoing. Newer therapeutic approaches address many aspects of BPD, including the pro-inflammatory component that characterizes this disorder. Finally, there is a greater need to understand the epidemiology and pathogenesis of the longer-term respiratory morbidity, most notably asthma, that persists in the preterm survivors of neonatal intensive care.

Effect of pulmonary surfactant on antimicrobial activity in vitro

Time-kill curve experiments were performed with linezolid, doripenem, tigecycline, moxifloxacin, and daptomycin against Staphylococcus aureus and with colistin, moxifloxacin, and doripenem against Pseudomonas aeruginosa to evaluate the effect of porcine pulmonary surfactant on antimicrobial activity. Pulmonary surfactant significantly impaired the activities of moxifloxacin and colistin. When antibiotics are being developed for respiratory tract infections, the method described here might be used to preliminarily quantify the effect of pulmonary surfactant on antimicrobial activity.

Surfactant therapy: past, present and future

Surfactant replacement in preterm infants with respiratory distress syndrome (RDS) has been a major therapeutic breakthrough and the most intensively studied intervention in neonatal medicine. Surfactant whether given prophylactically in the delivery room or in babies with established RDS reduces the severity of RDS, the incidence of air leaks and pneumothorax and, most importantly, neonatal death. Many randomized controlled trials have explored different strategies to optimize the effect of surfactant administration and have further improved neonatal outcome. Whenever indicated, surfactant should be administered as early as possible in the course of the RDS.

Neonatal stabilization and postresuscitation care

Neonatal mortality is a major health care concern worldwide. Neonatal resuscitation alone does not address most causes of neonatal mortality; caregivers need to be trained in both neonatal resuscitation and stabilization. Neonatal stabilization requires caregivers to evaluate whether babies are at-risk or unwell, to decide what interventions are required, and to act on those decisions. Several programs address neonatal stabilization in a variety of levels of care in both well-resourced and limited health care environments. This article suggests a shift in clinical, educational, and implementation science from a focus on resuscitation to one on the resuscitation-stabilization continuum.

Early versus delayed selective surfactant treatment for neonatal respiratory distress syndrome

BACKGROUND

Clinical trials have confirmed that surfactant therapy is effective in improving the immediate need for respiratory support and the clinical outcome of premature newborns. Trials have studied a wide variety of surfactant preparations used either to prevent (prophylactic or delivery room administration) or treat (selective or rescue administration) respiratory distress syndrome (RDS). Using either treatment strategy, significant reductions in the incidence of pneumothorax, as well as significant improvement in survival, have been noted. It is unclear whether there are any advantages to treating infants with respiratory insufficiency earlier in the course of RDS.

OBJECTIVES

To compare the effects of early versus delayed selective surfactant therapy for newborns intubated for respiratory distress within the first two hours of life. Planned subgroup analyses included separate comparisons for studies utilizing natural surfactant extract and synthetic surfactant.

SEARCH METHODS

We searched the Oxford Database of Perinatal Trials, MEDLINE (MeSH terms: pulmonary surfactant; text word: early; limits: age, newborn: publication type, clinical trial), PubMed, abstracts, conference and symposia proceedings, expert informants, and journal handsearching in the English language. For the updated search in April 2012 we searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, 2012, Issue 1) and PubMed (January 1997 to April 2012).

SELECTION CRITERIA

Randomized and quasi-randomized controlled clinical trials comparing early selective surfactant administration (surfactant administration via the endotracheal tube in infants intubated for respiratory distress, not specifically for surfactant dosage) within the first two hours of life versus delayed selective surfactant administration to infants with established RDS were considered for review.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes were excerpted from the reports of the clinical trials by the review authors. Subgroup analyses were performed based on type of surfactant preparation, gestational age, and exposure to prenatal steroids. Data analysis was performed in accordance with the standards of the Cochrane Neonatal Review Group.

MAIN RESULTS

Six randomized controlled trials met selection criteria. Two of the trials utilized synthetic surfactant (Exosurf Neonatal) and four utilized animal-derived surfactant preparations.The meta-analyses demonstrate significant reductions in the risk of neonatal mortality (typical risk ratio (RR) 0.84; 95% confidence interval (CI) 0.74 to 0.95; typical risk difference (RD) -0.04; 95% CI -0.06 to -0.01; 6 studies; 3577 infants), chronic lung disease (typical RR 0.69; 95% CI 0.55 to 0.86; typical RD -0.04; 95% CI -0.06 to -0.01; 3 studies; 3041 infants), and chronic lung disease or death at 36 weeks (typical RR 0.83; 95% CI 0.75 to 0.91; typical RD -0.06; 95% CI -0.09 to -0.03; 3 studies; 3050 infants) associated with early treatment of intubated infants with RDS.Intubated infants randomized to early selective surfactant administration also demonstrated a decreased risk of acute lung injury including a decreased risk of pneumothorax (typical RR 0.69; 95% CI 0.59 to 0.82; typical RD -0.05; 95% CI -0.08 to -0.03; 5 studies; 3545 infants), pulmonary interstitial emphysema (typical RR 0.60; 95% CI 0.41 to 0.89; typical RD -0.06; 95% CI -0.10 to -0.02; 3 studies; 780 infants), and overall air leak syndromes (typical RR 0.61; 95% CI 0.48 to 0.78; typical RD -0.18; 95% CI -0.26 to -0.09; 2 studies; 463 infants).A trend toward risk reduction for bronchopulmonary dysplasia (BPD) or death at 28 days was also evident (typical RR 0.94; 95% CI 0.88 to 1.00; typical RD -0.04; 95% CI -0.07 to -0.00; 3 studies; 3039 infants). No differences in other complications of RDS or prematurity were noted.Only two studies reported on infants under 30 weeks' gestation. Decreased risk of neonatal mortality and chronic lung disease or death at 36 weeks' postmenstrual age was noted.

AUTHORS' CONCLUSIONS

Early selective surfactant administration given to infants with RDS requiring assisted ventilation leads to a decreased risk of acute pulmonary injury (decreased risk of pneumothorax and pulmonary interstitial emphysema) and a decreased risk of neonatal mortality and chronic lung disease compared to delaying treatment of such infants until they develop worsening RDS.

The role of surfactant in respiratory distress syndrome

The key feature of respiratory distress syndrome (RDS) is the insufficient production of surfactant in the lungs of preterm infants. As a result, researchers have looked into the possibility of surfactant replacement therapy as a means of preventing and treating RDS. We sought to identify the role of surfactant in the prevention and management of RDS, comparing the various types, doses, and modes of administration, and the recent development. A PubMed search was carried out up to March 2012 using phrases: surfactant, respiratory distress syndrome, protein-containing surfactant, protein-free surfactant, natural surfactant, animal-derived surfactant, synthetic surfactant, lucinactant, surfaxin, surfactant protein-B, surfactant protein-C.Natural, or animal-derived, surfactant is currently the surfactant of choice in comparison to protein-free synthetic surfactant. However, it is hoped that the development of protein-containing synthetic surfactant, such as lucinactant, will rival the efficacy of natural surfactants, but without the risks of their possible side effects. Administration techniques have also been developed with nasal continuous positive airway pressure (nCPAP) and selective surfactant administration now recommended; multiple surfactant doses have also reported better outcomes. An aerosolised form of surfactant is being trialled in the hope that surfactant can be administered in a non-invasive way. Overall, the advancement, concerning the structure of surfactant and its mode of administration, offers an encouraging future in the management of RDS.

Surfactant for pulmonary haemorrhage in neonates

BACKGROUND

In the 1960s and 1970s, pulmonary haemorrhage (PH) occurred mainly in full-term infants with pre-existing illness with an incidence of 1.3 per 1000 live births. Risk factors for PH included severity of illness, intrauterine growth restriction, patent ductus arteriosus (PDA), coagulopathy and the need for assisted ventilation. Presently, PH occurs in 3% to 5% of preterm ventilated infants with severe respiratory distress syndrome (RDS) who often have a PDA and have received surfactant. The cause of PH is thought to be due to rapid lowering of intrapulmonary pressure, which facilitates left to right shunting across a PDA and an increase in pulmonary blood flow. Retrospective case reports and one prospective uncontrolled study have shown promising results for surfactant in treating PH.

OBJECTIVES

To evaluate the effect of surfactant treatment compared to placebo or no intervention on mortality and morbidities in neonates with PH.

SEARCH METHODS

For this update The Cochrane Library, Issue 2, 2012; MEDLINE; EMBASE; CINAHL; Clinicaltrials.gov; Controlled-trials.com; proceedings (2000 to 2011) of the Annual Meetings of the Pediatric Academic Societies (Abstracts2View) and Web of Science were searched on 8 February 2012.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that evaluated the effect of surfactant in the treatment of PH in intubated term or preterm (< 37 weeks) neonates with PH. Infants were included up to 44 weeks' postmenstrual age. The interventions studied were intratracheal instillation of surfactant (natural or synthetic, regardless of dose) versus placebo or no intervention.

DATA COLLECTION AND ANALYSIS

If studies were identified by the literature search, the planned analyses included risk ratio, risk difference, number needed to treat to benefit or to harm for dichotomous outcomes, and mean difference for continuous outcomes, with their 95% confidence intervals. A fixed-effect model would be used for meta-analyses. The risk of bias for included trials would be assessed. Heterogeneity tests, including the I(2) statistic, would be performed to assess the appropriateness of pooling the data and the results would be reported.

MAIN RESULTS

No trials were identified.

AUTHORS' CONCLUSIONS

No randomised or quasi-randomised trials that evaluated the effect of surfactant in PH were identified. Therefore, no conclusions from such trials can be drawn. In view of the promising results from studies with less strict study designs than a randomised controlled trial, there is reason to conduct further trials of surfactant for the treatment of PH in neonates.