Early versus late surfactant treatment in preterm infants of 27 to 32 weeks' gestational age: a multicenter controlled clinical trial

Clinical decision thresholds for surfactant administration in preterm infants: a systematic review and network meta-analysis

Background

The ideal threshold at which surfactant administration in preterm neonates with respiratory distress syndrome (RDS) is most beneficial is contentious. The aim of this systematic review was to determine the optimal clinical criteria to guide surfactant administration in preterm neonates with RDS.

Methods

The systematic review was registered in PROSPERO (CRD42022309433). Medline, Embase, CENTRAL and CINAHL were searched from inception till 16th May 2023. Only randomized controlled trials (RCTs) were included. A Bayesian random effects network meta-analysis (NMA) evaluating 33 interventions was performed. The primary outcome was requirement of invasive mechanical ventilation (IMV) within 7 days of life.

Findings

58 RCTs were included. In preterm neonates ≤30 weeks after adjusting for the confounding factor of modality of surfactant administration, an arterial alveolar oxygen tension ratio (aAO2) <0.36 (FiO2: 37-55%) was ranked the best threshold for decreasing the risk of IMV, very low certainty. Further, surfactant administration at an FiO2 40-45% possibly decreased mortality compared to rescue treatment when respiratory failure was diagnosed, certainty very low. The reasonable inference that could be drawn from these findings is that surfactant administration may be considered in preterm neonates of ≤30 weeks' with RDS requiring an FiO2 ≥ 40%. There was insufficient evidence for the comparison of FiO2 thresholds: 30% vs. 40%. The evidence was sparse for surfactant administration guided by lung ultrasound. For the sub-group >30 weeks, nebulized surfactant administration at an FiO2 < 30% possibly increased the risk of IMV compared to Intubate-Surfactant-Extubate at FiO2 < 30% and 40%, and less invasive surfactant administration at FiO2 40%, certainty very low.

Interpretation

Surfactant administration may be considered in preterm neonates of ≤30 weeks' with RDS if the FiO2 requirement is ≥40%. Future trials are required comparing lower FiO2 thresholds of 30% vs. 40% and that guided by lung ultrasound.

Funding

None.

Fetal growth restriction is associated with an altered cardiopulmonary and cerebral hemodynamic response to surfactant therapy in preterm lambs

BACKGROUND

Efficacy of surfactant therapy in fetal growth restricted (FGR) preterm neonates is unknown.

METHODS

Twin-bearing ewes underwent surgery at 105 days gestation to induce FGR in one twin by single umbilical artery ligation. At 123-127 days, catheters and flow probes were implanted in pulmonary and carotid arteries to measure flow and pressure. Lambs were delivered, intubated and mechanically ventilated. At 10 min, surfactant (100 mg kg^-1) was administered. Ventilation, oxygenation, and hemodynamic responses were recorded for 1 h before euthanasia at 120 min. Lung tissue and bronchoalveolar lavage fluid was collected for analysis of surfactant protein mRNA and phosphatidylcholines (PCs).

RESULTS

FGR preterm lambs were 26% lighter than appropriate for gestational age (AGA) lambs and had baseline differences in lung mechanics and pulmonary blood flows. Surfactant therapy reduced ventilator and oxygen requirements and improved lung mechanics in both groups, although a more rapid improvement in compliance and tidal volume was observed in AGA lambs. Surfactant administration was associated with decreased mean pulmonary and carotid blood flow in FGR but not AGA lambs. No major differences in surfactant protein mRNA or PC levels were noted.

CONCLUSIONS

Surfactant therapy was associated with an altered pulmonary and cerebral hemodynamic response in preterm FGR lambs.

Efficacy, Safety, and Usability of Remifentanil as Premedication for INSURE in Preterm Neonates

Background: We previously reported a 67% extubation failure with INSURE (Intubation, Surfactant, Extubation) using morphine as analgosedative premedication. Remifentanil, a rapid- and short-acting narcotic, might be ideal for INSURE, but efficacy and safety data for this indication are limited. Objectives: To assess whether remifentanil premedication increases extubation success rates compared with morphine, and to evaluate remifentanil's safety and usability in a teaching hospital context. Methods: Retrospective review of remifentanil orders for premedication, at a large teaching hospital neonatal intensive care unit (NICU). We compared INSURE failure rates (needing invasive ventilation after INSURE) with prior morphine-associated rates. Additionally, we surveyed NICU staff to identify usability and logistic issues with remifentanil. Results: 73 remifentanil doses were administered to 62 neonates (mean 31.6 ± 3.8 weeks' gestation). Extubation was successful in 88%, vs. 33% with morphine premedication (p < 0.001). Significant adverse events included chest wall rigidity (4%), one case of cardiopulmonary resuscitation (CPR) post-surfactant, naloxone reversal (5%), and notable transient desaturation (34%). Among 137 completed surveys, 57% indicated concerns, including delayed drug availability (median 1.1 h after order), rapid desaturations narrowing intubation timeframes and hindering trainee involvement, and difficulty with bag-mask ventilation after unsuccessful intubation attempts. Accordingly, 33% of ultimate intubators were attending neonatologists, versus 16% trainees. Conclusions: Remifentanil premedication was superior to morphine in allowing successful extubation, despite occasional chest wall rigidity and unfavorable conditions for trainees. We recommend direct supervision and INSURE protocols aimed at ensuring rapid intubation.

Efficacy and safety of surfactant replacement therapy for preterm neonates with respiratory distress syndrome in low- and middle-income countries: a systematic review

Surfactant replacement therapy (SRT) has been shown to reduce mortality and air leaks in preterm neonates from high-income countries (HICs). The safety and efficacy of SRT in low- and middle- income countries (LMICs) have not been systematically evaluated. The major objectives of this review were to assess the (1) efficacy and safety, and (2) feasibility and cost effectiveness of SRT in LMIC settings. We searched the following databases-MEDLINE, CENTRAL, CINAHL, EMBASE and WHOLIS using the search terms 'surfactant' OR 'pulmonary surfactant'. Both experimental and observational studies that enrolled preterm neonates with or at-risk of respiratory distress syndrome (RDS) and required surfactant (animal-derived or synthetic) were included. A total of 38 relevant studies were found; almost all were from level-3 neonatal units. Pooled analysis of two randomized controlled trials (RCTs) and 22 observational studies showed a significant reduction in mortality at the last available time point in neonates who received SRT (relative risk (RR) 0.67; 95% confidence interval (CI) 0.57 to 0.79). There was also a significant reduction in the risk of air leaks (five studies; RR 0.51; 0.29 to 0.90). One RCT and twelve observational studies reported the risk of bronchopulmonary dysplasia (BPD) with contrasting results; while the RCT and most before-after/cohort studies showed a significant reduction or no effect, the majority of the case-control studies demonstrated significantly higher odds of receiving SRT in neonates who developed BPD. Two studies-one RCT and one observational-found no difference in the proportion of neonates developing pulmonary hemorrhage, while another observational study reported a higher incidence in those receiving SRT. The failure rate of the intubate-surfactant-extubate (InSurE) technique requiring mechanical ventilation or referral varied from 34 to 45% in four case-series. No study reported on the cost effectiveness of SRT. Available evidence suggests that SRT is effective, safe and feasible in level-3 neonatal units and has the potential to reduce neonatal mortality and air leaks in low-resource settings as well. However, there is a need to generate more evidence on the cost effectiveness of SRT and its effect on BPD in LMIC settings.

Surfactant replacement therapy in extremely low gestational age newborns

There is a growing body of evidence over the last years suggesting continuous positive airway pressure (CPAP) ventilation being the first choice of ventilatory support in newborns with extremely low gestational age, and early rescue surfactant treatment being as effective as prophylactic therapy. The Intubation Surfactant Extubation procedure is discussed as an alternative procedure that may have the potential to combine the positive effects of surfactant and early CPAP. A further mode of surfactant administration, administration via a thin endotracheal catheter during spontaneous breathing with CPAP, has recently come into clinical use. This less invasive surfactant administration technique shows some short-term benefits but still cannot be recommended for general use in this vulnerable population. Long-term follow-up studies are needed to allow new recommendations on surfactant therapy in this high-risk population.

Surfactant

Exogenous pulmonary surfactant, widely used in neonatal care, is one of the best-studied treatments in neonatology, and its introduction in the 1990s led to a significant improvement in neonatal outcomes in preterm infants, including a decrease in mortality. This chapter provides an overview of surfactant composition and function in health and disease and summarizes the evidence for its clinical use.

Infants at risk of cerebral palsy: a systematic review of outcomes used in Cochrane studies of pregnancy, childbirth and neonatology

OBJECTIVE

To systematically review meta-analyses (MAs) and randomised controlled trials (RCTs) of interventions for infants at risk of cerebral palsy (CP), to determine if consensus exists in study end-points.

METHODS

MAs within the "Neonatal" and "Pregnancy and Childbirth" Review Groups in Cochrane Database of Systematic Reviews (to June 2011) were included if they contained risk factors for CP as a study end-point, and were either published in 2010 or 2011 or cited >20 times in Sciverse Scopus. Up to 20 RCTs from each MA were included. Outcome measures, definitions and cut-points for ordinal groupings were extracted from MAs and RCTs and frequencies calculated.

RESULTS

Twenty-two MAs and 165 RCTs were appraised. High consistency existed in types of outcome domains listed as important in MAs. For 10/16 most frequently cited outcome domains, <50% of RCTs contributed data for meta-analyses. Low consistency in outcome definitions, measures, cut-points in RCTs and long-term follow-up prohibited data aggregation.

CONCLUSIONS

Variation in outcome measurement and long-term follow up has hampered the ability of RCTs to contribute data on important outcomes for CP, resulting in lost opportunities to measure the impact of maternal and neonatal interventions. There is an urgent need for and long-term follow up of these interventions and an agreed set of standardised and clinically relevant common data elements for study end-points.

Analysis of the cost-effectiveness of surfactant treatment (Curosurf®) in respiratory distress syndrome therapy in preterm infants: early treatment compared to late treatment

Background

The best criteria for surfactant treatment in the perinatal period are unknown and this makes it of interest to consider the possible economic implications of lessening the use of more restrictive criteria.

Objective

The objective of this study is the evaluation of the costs of respiratory care for preterm infants with Respiratory Distress Syndrome (RDS) treated with "early rescue" surfactant compared to a "late rescue" strategy.

Methods

The study was carried out applying the costs of materials used, of staff and pharmacological therapy calculated in the Neonatal Intensive Care Unit (NICU) of an Italian hospital to the Verder et al. study (Pediatrics 1999) clinical data.

Results

The cost for patients treated with early strategy was slightly lower than for patients treated with late strategy (Euro 4,901.70 vs. Euro 4,960.07). The cost of treatment with surfactant was greater in the early group (Euro 458.49 vs. Euro 311.74), but this was compensated by the greater cost of treatment with Mechanical Ventilation (MV) in the late group (respectively Euro 108.85 vs. Euro 259.25).

Conclusions

The cost-effectiveness analysis performed in this study shows how early treatment with surfactant in preterm infants with RDS, as well as being clinically more effective, is associated with a slightly lower cost.

The Efficacy of Surfactant Replacement Therapy in the Growth-Restricted Preterm Infant: What is the Evidence?

BACKGROUND

Surfactant replacement therapy (SRT) is an integral part of management of preterm surfactant deficiency respiratory distress syndrome (RDS). Its role in the management of RDS has been extensively studied. However, its efficacy in the management of lung disease in preterm infants born with intrauterine growth restriction (IUGR) has not been systematically studied.

OBJECTIVE

To evaluate the efficacy of exogenous SRT in the management of preterm IUGR lung disease.

METHODS

A systematic search of all available randomized clinical trials (RCT) of SRT in preterm IUGR infants was done according to the standard Cochrane collaboration search strategy. Neonatal respiratory outcomes were compared between the preterm IUGR and appropriately grown for gestational age (AGA) preterm infant populations in eligible studies.

RESULTS

No study was identified which evaluated the efficacy or responsiveness of exogenous SRT in preterm IUGR infants as compared to preterm AGA-infants. The only study identified through the search strategy used small for gestational age (SGA; defined as less than tenth centile for birth weight) as a proxy for IUGR. The RCT evaluated the efficacy or responsiveness of SRT in preterm SGA group as compared to AGA-infants. The rate of intubation, severity of RDS, rate of surfactant administration, pulmonary air leaks, and days on the ventilator did not differ between both groups. However, the requirement for prolonged nasal continuous positive airway pressure (p < 0.001), supplemental oxygen therapy (p < 0.01), and the incidence of bronchopulmonary dysplasia at 28 days and 36 weeks (both p < 0.01) was greater in SGA-infants.

DISCUSSION

There is currently insufficient data available to evaluate the efficacy of SRT in preterm IUGR lung disease. A variety of research strategies will be needed to enhance our understanding of the role and rationale for use of SRT in preterm IUGR lung disease.

Surfactant replacement therapy for preterm and term neonates with respiratory distress

Respiratory failure secondary to surfactant deficiency is a major cause of morbidity and mortality in preterm infants. Surfactant therapy substantially reduces mortality and respiratory morbidity for this population. Secondary surfactant deficiency also contributes to acute respiratory morbidity in late-preterm and term neonates with meconium aspiration syndrome, pneumonia/sepsis, and perhaps pulmonary hemorrhage; surfactant replacement may be beneficial for these infants. This statement summarizes the evidence regarding indications, administration, formulations, and outcomes for surfactant-replacement therapy. The clinical strategy of intubation, surfactant administration, and extubation to continuous positive airway pressure and the effect of continuous positive airway pressure on outcomes and surfactant use in preterm infants are also reviewed.

Exogenous surfactant therapy in 2013: what is next? Who, when and how should we treat newborn infants in the future?

Background

Surfactant therapy is one of the few treatments that have dramatically changed clinical practice in neonatology. In addition to respiratory distress syndrome (RDS), surfactant deficiency is observed in many other clinical situations in term and preterm infants, raising several questions regarding the use of surfactant therapy.

Objectives

This review focuses on several points of interest, including some controversial or confusing topics being faced by clinicians together with emerging or innovative concepts and techniques, according to the state of the art and the published literature as of 2013. Surfactant therapy has primarily focused on RDS in the preterm newborn. However, whether this treatment would be of benefit to a more heterogeneous population of infants with lung diseases other than RDS needs to be determined. Early trials have highlighted the benefits of prophylactic surfactant administration to newborns judged to be at risk of developing RDS. In preterm newborns that have undergone prenatal lung maturation with steroids and early treatment with continuous positive airway pressure (CPAP), the criteria for surfactant administration, including the optimal time and the severity of RDS, are still under discussion. Tracheal intubation is no longer systematically done for surfactant administration to newborns. Alternative modes of surfactant administration, including minimally-invasive and aerosolized delivery, could thus allow this treatment to be used in cases of RDS in unstable preterm newborns, in whom the tracheal intubation procedure still poses an ethical and medical challenge.

Conclusion

The optimization of the uses and methods of surfactant administration will be one of the most important challenges in neonatal intensive care in the years to come.

Early routine versus late selective surfactant in preterm neonates with respiratory distress syndrome on nasal continuous positive airway pressure: a randomized controlled trial

BACKGROUND

Preterm neonates with respiratory distress syndrome (RDS) benefit from early application of nasal continuous positive airway pressure (nCPAP). However, it is not clear whether surfactant should be administered early as a routine to all such infants or later in a selective manner.

OBJECTIVE

It was the aim of this study to compare the efficacy of early routine versus late selective surfactant treatment in reducing the need for mechanical ventilation (MV) during the first week of life among moderate-sized preterm infants with RDS being supported by nCPAP.

METHODS

Infants born at 28(0/7) to 33(6/7) weeks of gestation with RDS and on nCPAP were randomly assigned within the first 2 h of life to early routine surfactant administration by the InSurE technique (early surfactant group) or to late selective administration of surfactant (late surfactant group). The primary outcome was need for MV in the first 7 days of life.

RESULTS

Among 153 infants randomized to early (n = 74) or late surfactant (n = 79) groups, the need for MV was significantly lower in the early surfactant group (16.2 vs. 31.6%; relative risk 0.41, 95% confidence interval 0.19-0.91). The incidence of pneumothorax (1.9 vs. 2.3%) and the need for supplemental O2 at 28 days (2.7 vs. 8.9%) were similar in the two groups.

CONCLUSION

Early routine surfactant administration within 2 h of life as compared to late selective administration significantly reduced the need for MV in the first week of life among preterm infants with RDS on nCPAP.

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.

Implantation of Ommaya reservoir in extremely low weight premature infants with posthemorrhagic hydrocephalus: a cautious option

OBJECTIVE

This study aims to evaluate effects and complications of the implantation of Ommaya reservoir in premature infants with posthemorrhagic hydrocephalus (PHH).

METHODS

The effects and complications of the implantation of Ommaya reservoir in seven premature infants with PHH were retrospectively analyzed. Intracapsular puncture of the reservoir was performed for draining cerebrospinal fluid.

RESULTS

Seven extremely low-weight premature infants with PHH (birthweight less than 1,000 g) were treated with the placement of an Ommaya reservoir. Ommaya reservoirs in five infants were removed, but were retained in two infants. Two premature infants had to undergo ventriculoperitoneal (VP) shunt. Postsurgical major complications (including skin dehiscence, cerebrospinal fluid (CSF) infection, ventricular hemorrhage, and CSF leak) occurred in 57% of all patients. Three infants of skin dehiscence and CSF leak occurred. Two infants of CSF infection occurred, as well as one clinically significant secondary hemorrhage. Six infants survived, and one died.

CONCLUSION

The implantation of Ommaya reservoir is a cautious option of treating low-weight premature infants with PHH because of a relatively high complication rate. However, VP shunt surgery may be avoided in some infants.

Antenatal corticosteroids trial in preterm births to increase neonatal survival in developing countries: study protocol

BACKGROUND

Preterm birth is a major cause of neonatal mortality, responsible for 28% of neonatal deaths overall. The administration of antenatal corticosteroids to women at high risk of preterm birth is a powerful perinatal intervention to reduce neonatal mortality in resource rich environments. The effect of antenatal steroids to reduce mortality and morbidity among preterm infants in hospital settings in developed countries with high utilization is well established, yet they are not routinely used in developing countries. The impact of increasing antenatal steroid use in hospital or community settings with low utilization rates and high infant mortality among premature infants due to lack of specialized services has not been well researched. There is currently no clear evidence about the safety of antenatal corticosteroid use for community-level births.

METHODS

We hypothesize that a multi country, two-arm, parallel cluster randomized controlled trial to evaluate whether a multifaceted intervention to increase the use of antenatal corticosteroids, including components to improve the identification of pregnancies at high risk of preterm birth and providing and facilitating the appropriate use of steroids, will reduce neonatal mortality at 28 days of life in preterm newborns, compared with the standard delivery of care in selected populations of six countries. 102 clusters in Argentina, Guatemala, Kenya, India, Pakistan, and Zambia will be randomized, and around 60,000 women and newborns will be enrolled. Kits containing vials of dexamethasone, syringes, gloves, and instructions for administration will be distributed. Improving the identification of women at high risk of preterm birth will be done by (1) diffusing recommendations for antenatal corticosteroids use to health providers, (2) training health providers on identification of women at high risk of preterm birth, (3) providing reminders to health providers on the use of the kits, and (4) using a color-coded tape to measure uterine height to estimate gestational age in women with unknown gestational age. In both intervention and control clusters, health providers will be trained in essential newborn care for low birth weight babies. The primary outcome is neonatal mortality at 28 days of life in preterm infants.

Biophysical interaction between corticosteroids and natural surfactant preparation: implications for pulmonary drug delivery using surfactant a a carrier

Intratracheal administration of corticosteroids using a natural pulmonary surfactant as a delivery vehicle has recently received significant attention in hopes of treating premature newborns with or at high risk for chronic lung disease. As a new practice, both the surfactant preparation used as the carrier and the corticosteroid delivered as the anti-inflammatory agent, and their mixing ratios, have not been standardized and optimized. Given the concern that corticosteroids delivered via a pulmonary surfactant may compromise its surface activity and thus worsen lung mechanics, the present study was carried out to characterize the biophysical interaction between a natural surfactant preparation, Infasurf, and two commonly used inhaled corticosteroids, budesonide and beclomethasone dipropionate (BDP). Based on surface activity measurements by the Langmuir balance and lateral film structure studied by atomic force microscopy, our findings suggest that when Infasurf is used as a carrier, a budesonide concentration less than 1 wt% of surfactant or a BDP concentration up to 10 wt % should not significantly affect the biophysical properties of Infasurf, thus being feasible for pulmonary delivery. Increasing corticosteroid concentration beyond this range leads to early collapse of the surfactant film due to increased film fluidization. Our study further suggests that different affinities to the surfactant films are responsible for the different behavior of budesonide and BDP. In addition to the translational value in treating chronic lung disease, this study may also have implications in inhaled steroid therapy to treat asthma.

Intra-amniotic surfactant for women at risk of preterm birth for preventing respiratory distress in newborns

BACKGROUND

Early surfactant reduces mortality and pulmonary complications in preterm infants with respiratory distress syndrome. However, current surfactant administration strategies require endotracheal intubation with or without continued mechanical ventilation. Bronchopulmonary dysplasia and chronic lung disease (CLD) are associated with mechanical ventilation and potentially life-long effects. Non-invasive methods of surfactant administration including intra-amniotic surfactant may avoid endotracheal intubation and mechanical ventilation, potentially preventing development of CLD.

OBJECTIVES

To determine if intra-amniotic instillation of surfactant for women at risk of preterm birth, compared to placebo or no treatment or post-delivery tracheal surfactant instillation, reduces morbidity or mortality, or both, in preterm infants. If intra-amniotic instillation is effective, in subgroup analysis to determine the effect of 1) gestational age; 2) type of surfactant; 3) dose; 4) timing; 5) indication; and 6) multiple pregnancy.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (August 2009), MEDLINE (1950-August 2009), handsearched the Proceedings of Pediatric Academic Societies (American Pediatric Society, Society for Pediatric Research and European Society for Pediatric Research) from 1990-2009 in Pediatric Research Journal and Abstracts online and the Proceedings of Perinatal Society of Australia and New Zealand (PSANZ) (1996-2009). We also searched the Science Citation Index (Web of Science) (August 2009) and checked reference lists of identified studies. We contacted Abbott Laboratories, Inc for unpublished studies.

SELECTION CRITERIA

Published, unpublished and ongoing randomised controlled, cluster-randomised or quasi-randomised trials of intra-amniotic instillation of surfactant for women at risk of preterm birth, compared to placebo or no treatment or post-delivery tracheal surfactant instillation.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed study eligibility and quality.

MAIN RESULTS

We found no trials were found met the inclusion criteria for this review.

AUTHORS' CONCLUSIONS

We identified no randomised trials that evaluated the effect of intra-amniotic instillation of surfactant for women at risk of preterm birth. Evidence from animal and observational human studies suggest that intra-amniotic surfactant administration is potentially safe, feasible and effective. Well designed trials of intra-amniotic instillation of surfactant for women at risk of preterm birth are needed.

Neurodevelopmental outcome and pulmonary morbidity two years after early versus late surfactant treatment: does it really differ?

AIM

To investigate whether neurodevelopmental outcome or pulmonary morbidity at age two years might be different after early versus late surfactant treatment in intubated preterm infants with severe respiratory distress syndrome (RDS).

METHODS

In 185 ex-preterm infants of 27-32 completed weeks of gestation, who were enrolled in a controlled trial of early versus late surfactant treatment (31 +/- 19 min vs. 202 +/- 80 min, respectively), a standardized follow up of medical history, pulmonary morbidity and neurodevelopmental outcome using the Griffiths scales were carried out.

RESULTS

Neurobehavioural and motor development was comparable in both groups, as was medical history and actual morbidity. However, in the early treatment group a delay in the subscale 'personal social' of the Griffiths test and in one 'milestone' of motor development (rolling over from supine to prone) was noticed, and the rate of increased muscular tone was significantly higher.

CONCLUSION

In terms of long-term morbidity or neurological development there is no obvious advantage of an immediate surfactant administration after intubation in preterm infants with RDS. This is in line with our results published earlier on morbidity at discharge, so improvement of gas exchange after intubation can first be awaited before surfactant is indicated.

Surfactant-replacement therapy for respiratory distress in the preterm and term neonate

Respiratory failure secondary to surfactant deficiency is a major cause of morbidity and mortality in preterm infants. Surfactant therapy substantially reduces mortality and respiratory morbidity for this population. Secondary surfactant deficiency also contributes to acute respiratory morbidity in late-preterm and term neonates with meconium aspiration syndrome, pneumonia/sepsis, and perhaps pulmonary hemorrhage; surfactant replacement may be beneficial for these infants. This statement summarizes indications, administration, formulations, and outcomes for surfactant-replacement therapy. The impact of antenatal steroids and continuous positive airway pressure on outcomes and surfactant use in preterm infants is reviewed. Because respiratory insufficiency may be a component of multiorgan dysfunction, preterm and term infants receiving surfactant-replacement therapy should be managed in facilities with technical and clinical expertise to administer surfactant and provide multisystem support.

Early surfactant administration with brief ventilation vs. selective surfactant and continued mechanical ventilation for preterm infants with or at risk for respiratory distress syndrome

BACKGROUND

Both prophylactic and early surfactant replacement therapy reduce mortality and pulmonary complications in ventilated infants with respiratory distress syndrome (RDS) compared with later selective surfactant administration. However, continued post-surfactant intubation and ventilation are risk factors for bronchopulmonary dysplasia (BPD). The purpose of this review was to compare outcomes between two strategies of surfactant administration in infants with RDS; prophylactic or early surfactant administration followed by prompt extubation, compared with later, selective use of surfactant followed by continued mechanical ventilation.

OBJECTIVES

To compare two treatment strategies in preterm infants with or at risk for RDS: early surfactant administration with brief mechanical ventilation (less than one hour) followed by extubation vs. later selective surfactant administration, continued mechanical ventilation, and extubation from low respiratory support. Two populations of infants receiving early surfactant were considered: spontaneously breathing infants with signs of RDS (who receive surfactant administration during evolution of RDS prior to requiring intubation for respiratory failure) and infants at high risk for RDS (who receive prophylactic surfactant administration within 15 minutes after birth).

SEARCH STRATEGY

Searches were made of the Oxford Database of Perinatal Trials, MEDLINE (1966 - December 2006), CINAHL (1982 to December Week 2, 2006), EMBASE (1980 - December 2006), Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 4, 2006), Pediatric Research (1990 - 2006), abstracts, expert informants and hand searching. No language restrictions were applied.

SELECTION CRITERIA

Randomized or quasi-randomized controlled clinical trials comparing early surfactant administration with planned brief mechanical ventilation (less than one hour) followed by extubation vs. selective surfactant administration continued mechanical ventilation, and extubation from low respiratory support.

DATA COLLECTION AND ANALYSIS

Data were sought regarding effects on the incidence of mechanical ventilation (ventilation continued or initiated beyond one hour after surfactant administration), incidence of bronchopulmonary dysplasia (BPD), chronic lung disease (CLD), mortality, duration of mechanical ventilation, duration of hospitalization, duration of oxygen therapy, duration of respiratory support (including CPAP and nasal cannula), number of patients receiving surfactant, number of surfactant doses administered per patient, incidence of air leak syndromes (pulmonary interstitial emphysema, pneumothorax), patent ductus arteriosus requiring treatment, pulmonary hemorrhage, and other complications of prematurity. Stratified analysis was performed according to inspired oxygen threshold for early intubation and surfactant administration in the treatment group: inspired oxygen within lower (FiO2< 0.45) or higher (FiO2 > 0.45) range at study entry. Treatment effect was expressed as relative risk (RR) and risk difference (RD) for categorical variables, and weighted mean difference (WMD) for continuous variables.

MAIN RESULTS

Six randomized controlled clinical trials met selection criteria and were included in this review. In these studies of infants with signs and symptoms of RDS, intubation and early surfactant therapy followed by extubation to nasal CPAP (NCPAP) compared with later selective surfactant administration was associated with a lower incidence of mechanical ventilation [typical RR 0.67, 95% CI 0.57, 0.79], air leak syndromes [typical RR 0.52, 95% CI 0.28, 0.96] and BPD [typical RR 0.51, 95% CI 0.26, 0.99]. A larger proportion of infants in the early surfactant group received surfactant than in the selective surfactant group [typical RR 1.62, 95% CI 1.41, 1.86]. The number of surfactant doses per patient was significantly greater among patients randomized to the early surfactant group [WMD 0.57 doses per patient, 95% CI 0.44, 0.69]. In stratified analysis by FIO2 at study entry, a lower threshold for treatment (FIO2< 0.45) resulted in lower incidence of airleak [typical RR 0.46 and 95% CI 0.23, 0.93] and BPD [typical RR 0.43, 95% CI 0.20, 0.92]. A higher treatment threshold (FIO2 > 0.45) at study entry was associated with a higher incidence of patent ductus arteriosus requiring treatment [typical RR 2.15, 95% CI 1.09, 4.13].

AUTHORS' CONCLUSIONS

Early surfactant replacement therapy with extubation to NCPAP compared with later selective surfactant replacement and continued mechanical ventilation with extubation from low ventilator support is associated with less need mechanical ventilation, lower incidence of BPD and fewer air leak syndromes. A lower treatment threshold (FIO2< 0.45) confers greater advantage in reducing the incidences of airleak syndromes and BPD; moreover a higher treatment threshold (FIO2 at study > 0.45) was associated with increased risk of PDA. These data suggest that treatment with surfactant by transient intubation using a low treatment threshold (FIO2< 0.45) is preferable to later, selective surfactant therapy by transient intubation using a higher threshold for study entry (FIO2 > 0.45) or at the time of respiratory failure and initiation of mechanical ventilation.

Observational study to compare the clinical efficacy of the natural surfactants Alveofact and Curosurf in the treatment of respiratory distress syndrome in premature infants

INTRODUCTION

Natural surfactants have been shown to be superior to synthetic surfactants in the treatment of neonatal respiratory distress syndrome (RDS). In Germany, Alveofact (A) and Curosurf (C) are the most frequently used natural surfactant preparations. The aim of this retrospective, observational study was to compare the effects of A and C on gas exchange and outcome in premature infants.

METHODS

During a 5-year period in our neonatal intensive care unit (NICU), 187 premature infants were treated with surfactant, with 82 receiving A and 105 receiving C. We recorded F(I)O(2) and gas exchange (PaO(2)/F(I)O(2) ratio, PaCO(2), SaO(2)) during the first 72h after surfactant application and the incidence of outcome parameters at day 28 (bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH grade III or IV), patent ductus arteriosus (PDA), pneumothorax, necrotizing enterocolites (NEC) and death). The differences between the patient groups were assessed by ANOVA or the calculation of relative risks. Bonferroni correction was used for multiple comparisons.

RESULTS

There were no statistically significant differences between infants treated with A and C in mean gestational age (28.4 vs. 28.4 weeks), birth weight (1210 vs.1258 g) and time of first surfactant application (60 vs. 90 min postnatal). We observed no significant between group differences in course of F(I)O(2) and blood gases, or in incidence at day 28 of BPD (41.7% vs. 42.8%), IVH III/IV (18.3% vs. 14.3%), pneumothorax (9.8% vs. 4.8%), PDA (23.2% vs. 21.9%), PVL (7.3% vs. 9.5%) and death (17% vs. 17.1%). There were also no statistically significant differences in the subgroup of infants <28 weeks. The lower incidence of NEC in A compared with C (1.2% vs. 10.5%, P=0.01) was not statistically significant after Bonferroni correction.

CONCLUSION

Independent of gestational age no significant difference in the clinical efficacy of A and C was observed.

Oxygenation and ventilation in spontaneously breathing very preterm infants with nasopharyngeal CPAP in the delivery room

AIM

To provide data on ventilation, oxygenation and acid-base state from birth to 48 h in very preterm infants treated with lung recruitment manoeuvre and nasopharyngeal continuous positive airway pressure in the delivery room.

METHODS

Subjects of this prospective observational cohort study were 48 of 61 infants enrolled in a randomised controlled trial to test two lung recruitment manoeuvres after birth. The infants had received an arterial line in the delivery room. The outcome measures were data on oxygenation, ventilation and acid-base state during spontaneous breathing.

RESULTS

Data are presented as (n [%]; median [minimum-maximum]). 22 of 48 (46%) infants (gestational age, 26.4 [25.0-28.9] weeks; birth weight 870 [540-1310] g) were never intubated during the study. The FiO(2) of these infants was low (0.4 [0.21-0.45] at 45 min and 0.21 [0.21-0.5] at 48 h). PCO(2) reached its maximum at 24 (11-44) min (8 [6.4-10.8] kPa) and decreased below 6.7 kPa (median) within 3 h. The incidence of intracranial haemorrhage/periventricular leukomalacia did not increase with hypercapnia (pCO(2) > 8 kPa).

CONCLUSION

A transient period of hypercapnia after birth may occur in spontaneously breathing very preterm infants supported with nasopharyngeal continuous positive airway pressure in the delivery room. The incidence of cerebral damage was not increased in infants with hypercapnia.

Lung surfactants

PURPOSE

The pharmacology, clinical efficacy, and cost considerations of exogenous lung surfactants are reviewed.

SUMMARY

Exogenous pulmonary surfactants, along with advancements in ventilatory care, have significantly reduced the incidence of respiratory distress syndrome (RDS) and its related complications in infants. The following exogenous surfactants are approved for the prophylaxis and treatment (rescue) of neonatal RDS: beractant, a modified natural surfactant; calfactant and poractant, both natural surfactants; and colfosceril, a synthetic surfactant that is not currently available in the United States. Lucinactant, a synthetic surfactant, is under investigation and received approvable status from the Food and Drug Administration in February 2005. The surfactants are delivered directly to their site of action, and only small amounts reach the systemic circulation. Bioavailability to the distal airways and alveoli depends on the method of delivery, the stage and severity of pulmonary disease, and the properties of the particular surfactant. According to data from clinical trials, the use of exogenous surfactant therapy for rescue within the first two hours of life appears to be as efficacious as prophylaxis in most premature infants.

CONCLUSION

Comparative trials of surfactants have proven the efficacy of both synthetic and natural surfactants in the prevention and treatment of RDS. However, these trials have universally demonstrated greater reduction in the immediate need for ventilator support in infants who receive natural surfactants. Natural preparations cause less pneumothorax, bronchopulmonary dysplasia, and mortality compared with synthetic preparations. Synthetic agents offer the potential advantages of an unlimited supply with consistent pharmaceutical quality and no risk of transmitting infectious disease or causing immunologic sensitization.

Overview of surfactant replacement trials

Clinical trials have evaluated the overall efficacy of surfactant therapy, as well as the relative efficacy of different surfactant preparations, the optimal timing of administration and the optimal dosage. Surfactant therapy leads to significant clinical improvement in infants at risk for, or having, respiratory distress syndrome (RDS). Clinical trials that compared the effects of synthetic or animal-derived surfactant preparations to placebo or no therapy demonstrate that surfactant therapy lead to rapid improvement in oxygenation, decreased ventilator support, decreased risk of pneumothorax, and mortality. Earlier treatment, prophylactic treatment of infants at high risk of developing RDS, and selective re-treatment leads to improved clinical outcome as well. Currently available animal-derived surfactants are superior to non-protein-containing synthetic surfactants. Ongoing evaluation will determine if important differences in animal-derived products are noted. Future trials will evaluate third-generation surfactant products and further refine what constitutes optimal use of surfactant.

Surfactant therapy for respiratory distress syndrome in premature neonates: a comparative review

Exogenous surfactant therapy has been part of the routine care of preterm neonates with respiratory distress syndrome (RDS) since the beginning of the 1990s. Discoveries that led to its development as a therapeutic agent span the whole of the 20th century but it was not until 1980 that the first successful use of exogenous surfactant therapy in a human population was reported. Since then, randomized controlled studies demonstrated that surfactant therapy was not only well tolerated but that it significantly reduced both neonatal mortality and pulmonary air leaks; importantly, those surviving neonates were not at greater risk of subsequent neurological impairment. Surfactants may be of animal or synthetic origin. Both types of surfactants have been extensively studied in animal models and in clinical trials to determine the optimum timing, dose size and frequency, route and method of administration. The advantages of one type of surfactant over another are discussed in relation to biophysical properties, animal studies and results of randomized trials in neonatal populations. Animal-derived exogenous surfactants are the treatment of choice at the present time with relatively few adverse effects related largely to changes in oxygenation and heart rate during surfactant administration. The optimum dose of surfactant is usually 100 mg/kg. The use of surfactant with high frequency oscillation and continuous positive pressure modes of respiratory support presents different problems compared with its use with conventional ventilation. The different components of surfactant have important functions that influence its effectiveness both in the primary function of the reduction of surface tension and also in secondary, but nonetheless just as important, role of lung defense. With greater understanding of the individual surfactant components, particularly the surfactant-associated proteins, development of newer synthetic surfactants has been made possible. Despite being an effective therapy for RDS, surfactant has failed to have a significant impact on the incidence of chronic lung disease in survivors. Paradoxically the cost of care has increased as surviving neonates are more immature and consume a greater proportion of neonatal intensive care resources. Despite this, surfactant is considered a cost-effective therapy for RDS compared with other therapeutic interventions in premature infants.

Early surfactant administration with brief ventilation vs selective surfactant and continued mechanical ventilation for preterm infants with or at risk for respiratory distress syndrome

BACKGROUND

Both prophylactic and early surfactant replacement therapy, compared with later selective surfactant administration, reduce mortality and pulmonary complications in ventilated infants with respiratory distress syndrome (RDS). However, continued post-surfactant intubation and ventilation are risk factors for chronic lung disease. Whether prophylactic or early surfactant administration followed by prompt extubation, compared with later, selective use of surfactant followed by continued mechanical ventilation reduces the need for mechanical ventilation and the incidence of chronic lung disease is unknown.

OBJECTIVES

To compare two treatment strategies in preterm infants with, or at risk for, RDS: early surfactant administration with brief mechanical ventilation (less than one hour) followed by extubation, vs later, selective surfactant administration, continued mechanical ventilation and extubation from low respiratory support. Two populations of infants receiving early surfactant were considered: spontaneously breathing infants with signs of RDS (surfactant administration during evolution of RDS prior to requiring intubation for respiratory failure) and infants at high risk for RDS (prophylactic surfactant administration within 15 minutes after birth).

SEARCH STRATEGY

Searches were made of the Oxford Database of Perinatal trials, MEDLINE (1966-December 2003), CINAHL (1982-December 2003), EMBASE (1980-December 2003), Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2004), Pediatric Research (1990-2003), abstracts, expert informants and hand searching. No language restrictions were applied.

SELECTION CRITERIA

Randomized or quasi-randomized controlled clinical trials comparing early surfactant administration with planned brief mechanical ventilation (less than one hour) followed by extubation, vs selective surfactant administration, continued mechanical ventilation and extubation from low respiratory support.

DATA COLLECTION AND ANALYSIS

Data were sought regarding effects on incidence of mechanical ventilation (ventilation continued or initiated beyond one hour after surfactant administration), incidence of bronchopulmonary dysplasia (BPD), chronic lung disease (CLD), mortality, duration of mechanical ventilation, duration of hospitalization, time in oxygen, duration of respiratory support (including CPAP and nasal cannula), number of patients receiving surfactant, number of surfactant doses administered per patient, incidence of air leak syndromes (pulmonary interstitial emphysema, pneumothorax), patent ductus arteriosus requiring treatment, pulmonary hemorrhage, and other complications of prematurity. Treatment effect was expressed as relative risk (RR) and risk difference (RD) for categorical variables, and weighted mean difference (WMD) for continuous variables.

MAIN RESULTS

Four randomized controlled clinical trials met selection criteria and were included in this review. In these studies of infants with signs of RDS, intubation and early surfactant therapy followed by extubation to nasal CPAP (NCPAP) compared with later selective surfactant administration was associated with a lower incidence of mechanical ventilation [typical RR 0.70, 95% CI 0.59, 0.84]. None of the trials reported a significant difference in the incidence of BPD or CLD; however, meta-analysis for this outcome cannot yet be performed because the primary data from three of the trials have not yet been published in full. A larger proportion of infants in the early surfactant group received surfactant than in the selective surfactant group [typical RR 1.59, 95% CI 1.35, 1.88]. The number of surfactant doses per patient was significantly greater among patients randomized to the early surfactant group [WMD 0.51 doses per patient, 95% CI 0.36, 0.65]. Trends towards a decreased incidence of air leak syndromes (two studies) and a higher incidence of patent ductus arteriosus requiring treatment (one study) were seen in the early surfactant group. There was no evidence of effect on time in oxygen or duration of mechanical ventilation.

REVIEWERS' CONCLUSIONS

Early surfactant replacement therapy with extubation to NCPAP compared with later, selective surfactant replacement and continued mechanical ventilation with extubation from low ventilator support is associated with a reduced need for mechanical ventilation and increased utilization of exogenous surfactant therapy. There is insufficient evidence at present to reliably evaluate effect on BPD or CLD.

Calfactant sterility in multiple doses from single-use vials

BACKGROUND

Calfactant is an exogenous surfactant used to treat and prevent respiratory distress syndrome in the newborn infant. It is available in single-use preservative-free vials, but contains enough volume to provide multiple doses to small infants.

OBJECTIVE

To measure the preservation of calfactant sterility at 12- and 24-hour intervals following initial violation of vial contents and to extrapolate cost savings associated with product conservation.

METHODS

A prospective sterility study was performed using calfactant suspension obtained from vials prescribed for infants who had received their dose in the delivery room or the neonatal intensive care unit (NICU). After initial vial entry, test vials were stored in the NICU pharmacy satellite under refrigeration (temperature range 2.2-7.2 degrees C). Re-entry of test vials and sample removal was performed 12 and 24 hours after initial entry with an 18- or 20-gauge needle. All samples were removed by a neonatal respiratory therapist and placed into 3-mL latex-free, Leur-lok plastic syringes and examined by 3 culture media: MacConkey agar, blood agar, and thioglycollate broth.

RESULTS

A total of 89 surfactant samples from 45 vials were cultured; 45 at a mean time of 13.36 hours (range 11-41) and 44 at a mean time of 25.8 hours (range 22-60) after initial vial entry. These samples represented the technique of multiple respiratory therapists. All samples were negative for bacterial growth at 24 and 48 hours (beta = 0.9).

CONCLUSIONS

Results from this short-term sterility study represent an initial step in the evaluation of multiple doses of surfactant from a single-use vial. The data suggest that 1-2 re-entries into a vial of calfactant, within 24 hours after the initial breach, can be a safe and economical method of providing more than a single dose of surfactant to infants weighing <1 kg. We encourage each institution to reproduce these findings before applying this concept to their patients.

Effects of exogenous surfactant supplementation and partial liquid ventilation on acute lung injury induced by wood smoke inhalation in newborn piglets

OBJECTIVE

To investigate the beneficial effects of exogenous surfactant supplementation (ESS) and partial liquid ventilation (PLV) in treating acute lung injury induced by wood smoke inhalation.

DESIGN

A prospective, randomized, controlled, multigroup study.

SETTING

An animal research laboratory at a medical center.

SUBJECTS

Newborn piglets (n = 29; 1.80 +/- 0.06 kg) of either sex.

INTERVENTIONS

Animals were ventilated with a tidal volume of 15 mL/kg, a rate of 30 breaths/min, a positive end-expiratory pressure of 5 cm H(2)O, and an Fio(2) of 1.0. After the induction of acute lung injury by wood smoke inhalation, animals were randomly assigned to receive either conventional mechanical ventilation (CMV) or PLV with or without ESS pretreatment. Animals were grouped as CMV, ESS-CMV, PLV, and ESS-PLV.

MEASUREMENTS AND MAIN RESULTS

Arterial blood gases, cardiovascular hemodynamics, dynamic lung compliance, and total lung injury scores were measured. After smoke inhalation, all four groups displayed similar high arterial carboxyhemoglobin levels, low Pao(2) (<150 mm Hg), and low dynamic lung compliance (<66% of its baseline). In the CMV group, these deleterious conditions remained during the 4-hr observation period, and severe lung injury was noted histologically. All treatment groups demonstrated a significant increase in Pao(2) compared with the CMV group. In addition, both the PLV and ESS-PLV groups displayed significant improvements in dynamic lung compliance and in their histologic outcomes. Nevertheless, none of the variables measured in the PLV group differed from those measured in the ESS-PLV group.

CONCLUSIONS

In a newborn piglet model of smoke inhalation injury, PLV or ESS improved oxygenation. PLV compared favorably with ESS in its greater improvements in lung compliance and lung pathology. However, the combined therapy of ESS and PLV was not clearly superior to PLV alone during the observation period.

Treatment with bovine surfactant in severe acute respiratory distress syndrome in children: a randomized multicenter study

OBJECTIVE

To determine whether bovine surfactant given in cases of severe pediatric acute respiratory distress syndrome (ARDS) improves oxygenation.

DESIGN

Single-center study with 19 patients, followed by a multicenter randomized comparison of surfactant with a standardized treatment algorithm. Primary endpoint PaO(2)/FIO(2) at 48 h, secondary endpoints: PaO(2)/FIO(2) at 2, 4, 12, and 24 h, survival, survival without rescue, days on ventilator, subgroups analyzed by analysis of variance to identify patients who might benefit from surfactant.

SETTING

Multicenter study in 19 reference centers for ARDS.

PATIENTS

Children after the 44th postconceptional week and under 14 years old, admitted for at least 4 h, ventilated for 12-120 h, and without heart failure or chronic lung disease. In the multicenter study 35 patients were recruited; 20 were randomized to the surfactant group and 15 to the nonsurfactant group. Decreasing recruitment of patients led to a preliminary end of this study.

INTERVENTIONS

Administration of 100 mg/kg bovine surfactant intratracheally under continuous ventilation and PEEP, as soon as the PaO(2)/FIO(2) ratio dropped to less than 100 for 2 h (in the pilot study increments of 50 mg/kg as long as the PaO(2)/FIO(2) did not increase by 20%). A second equivalent dose within 48 h was permitted.

RESULTS

In the pilot study the PaO(2)/FIO(2) increased by a mean of 100 at 48 h (n=19). A higher PaO(2)/FIO(2) ratio was observed in the surfactant group 2 h after the first dose (58 from baseline vs. 9), at 48 h there was a trend towards a higher ratio (38 from baseline vs. 22). The rate of rescue therapy was significantly lower in the surfactant group. Outcome criteria were not affected by a second surfactant dose (n=11). A significant difference in PaO(2)/FIO(2) in favor of surfactant at 48 h was found in the subgroup with an initial PaO(2)/FIO(2) ratio higher than 65 and in patients without pneumonia. CONCLUSIONS. Surfactant therapy in severe ARDS improves oxygenation immediately after administration. This improvement is sustained only in the subgroup of patients without pneumonia and that with an initial PaO(2)/FIO(2) ratio higher than 65

Acute side effects of surfactant treatment

There is increasing evidence from studies on animals and humans that surfactant administration may have a great impact on cerebral perfusion. These effects may result from direct pulmonary or hemodynamic changes (or a combination of both), but may also be due to rapid alterations of blood gases. Type of surfactant and mode of administration seem to play an important role. Results from the pertinent literature are summarised with a special emphasis on how to avoid potentially harmful side effects of surfactant therapy in preterm infants.

Current surfactant use in premature infants

Exogenous surfactant therapy has been a significant advance in the management of preterm infants with RDS. It has become established as a standard part of the management of such infants. Both natural and synthetic surfactants lead to clinical improvement and decreased mortality, with natural surfactants having additional advantages over currently available synthetic surfactants. The use of prophylactic surfactant administered after initial stabilization at birth to infants at risk for RDS has benefits compared with rescue surfactant given to treat infants with established RDS. In infants who do not receive prophylaxis, earlier treatment (before 2 hours) has benefits over later treatment. The use of multiple doses of surfactant is a superior strategy to the use of a single dose, whereas the use of a higher threshold for retreatment seems to be as effective as a low threshold. Adverse effects of surfactant therapy are infrequent and usually not serious. Long-term follow-up of infants treated with surfactant in the neonatal period is reassuring. In the future we are likely to see the development of new types of surfactants. Further research is required to determine the optimal use of surfactant in conjunction with other respiratory interventions.

High-versus low-threshold surfactant retreatment for neonatal respiratory distress syndrome

Surfactant therapy has become an effective standard therapy for infants with respiratory distress syndrome (RDS). The first dose may be given either as prophylaxis immediately after delivery, or as rescue after an infant has developed RDS. Second and subsequent doses are currently recommended by the manufacturers to be administered at minimal levels of respiratory support.

PURPOSE

This study compared the relative efficacy of administering second and subsequent doses of Infasurf surfactant at a low threshold (FIO(2) >30%, still requiring endotracheal intubation) versus a high threshold (FIO(2) >40%, mean airway pressure >7 cm H(2)O) of respiratory support.

METHODS

A total of 2484 neonates received a first dose of surfactant; 1267 reached conventional retreatment criteria and were randomized to be retreated according to low- or high-threshold criteria. They were then retreated at a minimum of 6-hour intervals each time they reached their assigned threshold until receiving a maximum of 4 total doses. Subjects were stratified by whether they received their first dose by prophylaxis or rescue and by whether their lung disease was considered complicated (evidence of perinatal compromise or sepsis) or uncomplicated.

RESULTS

Among the patients randomized, 33% of prophylaxis and 23% of rescue subjects met criteria for the complicated stratum. Although infants allocated to the high-threshold strategy were receiving slightly more oxygen at 72 hours, there was no difference in the number receiving mechanical ventilation at 72 hours or in the secondary respiratory outcomes (requirement for supplemental oxygen or mechanical ventilation at 28 days, supplemental oxygen at 36 weeks' postconceptional age, inspired oxygen concentration >60% at any time). However, there was a significantly higher mortality for infants with complicated RDS who had received retreatment according to the high-threshold strategy.

CONCLUSIONS

We conclude that equal efficacy can be realized by delaying surfactant retreatment of infants with uncomplicated RDS until they have reached a higher level of respiratory support than is the current standard. We speculate that this would result in a substantial cost-saving from less utilization of drug. Conversely, we believe that infants with complicated RDS should continue to be treated by the low-threshold retreatment strategy, which is currently recommended by the manufacturers of the commercially available surfactants.

Neonatal outcome in small for gestational age infants: do they really better?

BACKGROUND

There still is a controversy as to the neonatal outcome of small for gestational age (SGA) infants compared to a appropriate for gestational age (AGA) preterm infants. As a part of a randomized multicenter trial on timing of bovine surfactant therapy, we aimed at investigating short-term outcome variables in SGA-infants compared with AGA-infants.

METHODS

SGA-infants were classified weighing below the 10th percentile at birth and were compared to AGA-infants in terms of prenatal and neonatal characteristics and neonatal outcome.

RESULTS

A total of 317 infants were enrolled, 59 SGA- and 258 AGA-infants. Both groups did not differ in gestational age, however, SGA-infants had a lower birth weight. Preterm premature rupture of fetal membranes was observed more frequently in AGA-, preeclampsia in SGA-infants. The rate of intubation, severity of RDS, rate of surfactant administration, pulmonary airleaks and days on the ventilator did not differ between both groups. However prolonged nasal CPAP, supplemental oxygen therapy and chronic lung disease at 28 days and 36 weeks was diagnosed more often in SGA-infants. Furthermore mortality was significantly higher in SGA-infants as well as total NICU and total hospital days.

CONCLUSION

As SGA-infants have an increased mortality rate and an increased risk for developing chronic lung disease, further studies should focus on prevention of intrauterine growth restriction and its complications.

Early versus delayed selective surfactant treatment for neonatal respiratory distress syndrome

BACKGROUND

This section is under preparation and will be included in the next issue.

OBJECTIVES

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

SEARCH STRATEGY

Searches were made of 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 hand searching in the English language.

SELECTION CRITERIA

Only 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 2 hours of life versus delayed selective surfactant administration to infants with established respiratory distress syndrome were considered for review.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes including the incidence of pneumothorax, patent ductus arteriosus, pulmonary interstitial emphysema, pulmonary hemorrhage, necrotizing enterocolitis, retinopathy of prematurity, intraventricular hemorrhage (any and severe IVH), bronchopulmonary dysplasia, chronic lung disease, neonatal mortality, mortality prior to hospital discharge, bronchopulmonary dysplasia or death, and chronic lung disease or death were excerpted from the reports of the clinical trials by the reviewers. Data regarding the average number of surfactant doses per infant were also analyzed. Further analysis of data with regard to surfactant type was performed. Data analysis was performed in accordance with the standards of the Cochrane Neonatal Review Group.

MAIN RESULTS

Four randomized controlled trials met selection criteria. Two of the trials utilized synthetic surfactant (Exosurf Neonatal) and two utilized a natural surfactant extract. The meta-analyses demonstrated significant reductions in risk of pneumothorax (Typical RR 0.70, 95%CI 0.59, 0.82; Typical RD -0.05, 95%CI -0.08, -0.03), and pulmonary interstitial emphysema (Typical RR 0.63, 95%CI 0.43, 0.93; Typical RD -0.06, 95%CI -0.10, -0.01) in infants randomized to early selective surfactant administration. Infants randomized to early selective surfactant administration also demonstrated a decreased risk of neonatal mortality (Typical RR 0.87, 95%CI 0.77, 0.99; Typical RD -0.03, 95%CI -0.06, -0.00), chronic lung disease (Typical RR 0.70, 95%CI 0. 55, 0.88; Typical RD -0.03, 95%CI -0.05, -0.01), and chronic lung disease or death at 36 weeks (Typical RR 0.84, 95%CI 0.75, 0.93; Typical RD -0.06, 95%CI -0.09, -0.03). A trend toward risk reduction for bronchopulmonary dysplasia or death at 28 days was also evident (Typical RR 0.94, 95%CI 0.88, 1.00; Typical RD -0.04, 95%CI -0.07, -0.00). No differences in other complications of RDS or prematurity were noted.

REVIEWER'S 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 established RDS.