Study protocol for the POPART study-Prophylactic Oropharyngeal surfactant for Preterm infants: A Randomised Trial

Prophylactic Oropharyngeal Surfactant for Preterm Newborns at Birth: A Randomized Clinical Trial

Importance

Preterm newborns at risk of respiratory distress syndrome are supported with continuous positive airway pressure (CPAP). Many newborns worsen despite CPAP and are intubated for surfactant administration, an effective therapy for treatment of respiratory distress syndrome. Endotracheal intubation is associated with adverse effects. Pharyngeal administration of surfactant to preterm animals and humans has been reported as an alternative.

Objective

To assess whether giving prophylactic oropharyngeal surfactant to preterm newborns at birth would reduce the rate of intubation for respiratory failure.

Design, Setting, and Participants

This unblinded, parallel-group randomized clinical trial (Prophylactic Oropharyngeal Surfactant for Preterm Infants [POPART]) was conducted from December 17, 2017, to September 11, 2020, at 9 tertiary neonatal intensive care units in 6 European countries. Newborns born before 29 weeks of gestation without severe congenital anomalies, for whom intensive care was planned, were eligible for inclusion. The data were analyzed from July 27, 2022, to June 20, 2023.

Intervention

Newborns were randomly assigned to receive oropharyngeal surfactant at birth in addition to CPAP or CPAP alone. Randomization was stratified by center and gestational age (GA).

Main Outcomes and Measures

The primary outcome was intubation in the delivery room for bradycardia and/or apnea or in the neonatal intensive care unit for prespecified respiratory failure criteria within 120 hours of birth. Caregivers were not masked to group assignment.

Results

Among 251 participants (mean [SD] GA, 26 [1.5] weeks) who were well matched at study entry, 126 (69 [54.8%] male) with a mean (SD) birth weight of 858 (261) grams were assigned to the oropharyngeal surfactant group, and 125 (63 [50.4%] male) with a mean (SD) birth weight of 829 (253) grams were assigned to the control group. The proportion of newborns intubated within 120 hours was not different between the groups (80 [63.5%) in the oropharyngeal surfactant group and 81 [64.8%] in the control group; relative risk, 0.98 [95% CI, 0.81-1.18]). More newborns assigned to the oropharyngeal surfactant group were diagnosed with and treated for pneumothorax (21 [16.6%] vs 8 [6.4%]; P = .04).

Conclusions and Relevance

This randomized clinical trial found that administration of prophylactic oropharyngeal surfactant to newborns born before 29 weeks' GA did not reduce the rate of intubation in the first 120 hours of life. These findings suggest that administration of surfactant into the oropharynx immediately after birth in addition to CPAP should not be routinely used.

Trial Registration

EudraCT: 2016-004198-41.

Alternative routes of surfactant application - An update

Non-invasive modes of respiratory support have been shown to be the preferable way of primary respiratory support of preterm infants with respiratory distress syndrome (RDS). The avoidance of invasive mechanical ventilation can be beneficial for preterm infants in reduction of morbidity and even mortality. However, it is well-established that some infants managed with non-invasive respiratory support from the outset have symptomatic RDS to a degree that warrants surfactant administration. Infants for whom non-invasive respiratory support ultimately fails are prone to adverse outcomes, occurring at a frequency on par with the group intubated primarily. This raises the question how to combine non-invasive respiratory support with surfactant therapy. Several methods of less or minimally invasive surfactant therapy have been developed to address the dilemma between avoidance of mechanical ventilation and administration of surfactant. This paper describes the different methods of less invasive surfactant application, reports the existing evidence from clinical studies, discusses the limitations of each of the methods and the open and future research questions.

Can we balance early exogenous surfactant therapy and non-invasive respiratory support to optimise outcomes in extremely preterm infants? A nuanced review of the current literature

Therapeutic advances have significantly improved the survival of premature infants. However, a high burden of bronchopulmonary dysplasia (BPD) persists. Aiming at prevention of neonatal lung injury, continuous positive airway pressure (CPAP) and non-invasive ventilation (NIV) strategies have replaced mechanical ventilation for early respiratory support and treatment of respiratory distress syndrome. Multiple randomised controlled trials have demonstrated that broad application of CPAP/NIV decreases exposure to mechanical ventilation and reduces rates of BPD. Here, we explore why this treatment effect is not larger. We discuss that today's neonatal intensive care unit population evolving from the premature to the extremely premature infant demands better targeted therapy, and indicate how early and accurate identification of preterm infants likely to fail CPAP/NIV could increase the treatment effect and minimise the potential harm of delaying exogenous surfactant therapy in these infants. Finally, we argue that less invasive modes of surfactant administration may represent both a pragmatic and beneficial approach in combining CPAP/NIV and early surfactant. Beneficial treatment effects might be higher than reported in the literature when targeting this approach to preterm infants suffering from respiratory failure primarily due to surfactant deficiency. Considering ongoing limitations of current approaches and focusing both on prospects and potential harm of modified strategies, this commentary ultimately addresses the need and the challenge to prove that pushing early CPAP/NIV and strategies of early and less invasive surfactant application prevents lung injury in the long term.

Surfactant delivery strategies to prevent bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is one of the most devastating morbidities of preterm infants. Antenatal factors like growth restriction and inflammation are risk factors for its development. Use of oxygen and positive pressure ventilation, which are often necessary to treat respiratory distress syndrome (RDS), increase the risk for development of BPD. Continuous positive airway pressure (CPAP) as primary respiratory support allows for avoidance of positive pressure ventilation in many cases but may lead to a delay of surfactant administration which is a proven therapy for RDS. Several alternative surfactant delivery strategies, including nebulization of surfactant, pharyngeal instillation of surfactant, delivery of surfactant via supraglottic airway device or surfactant delivery via a thin endotracheal catheter have been described which allow for the benefit of surfactant therapy while on CPAP. This review reports available data and discusses the existing evidence of their value in preventing BPD as well as further research directions.

Should less invasive surfactant administration (LISA) become routine practice in US neonatal units?

The harmful effects of mechanical ventilation (MV) on the preterm lung are well established. Avoiding MV at birth and stabilization on continuous positive airway pressure (CPAP) decreases the composite outcome of death or bronchopulmonary dysplasia. Although preterm infants are increasingly being admitted to the neonatal intensive care unit on CPAP, centers differ in the ability to manage infants primarily on CPAP. Over the last decade, less invasive surfactant administration (LISA), a method of administering surfactant with a thin catheter, has been devised and has been shown to decrease the need for MV and improve outcomes compared to surfactant administration via an endotracheal tube following intubation. While LISA has been widely adopted in Europe and other countries, its use is not widespread in the United States. This article provides a summary of the existing evidence on LISA, and practical guidance for US units choosing to implement a change of practice incorporating optimization of CPAP and LISA. IMPACT: The accumulated body of evidence for less invasive surfactant administration (LISA), a widespread practice in other countries, justifies its use as an alternative to intubation and surfactant administration in US neonatal units. This article summarizes the current evidence for LISA, identifies gaps in knowledge, and offers practical tips for the implementation of LISA as part of a comprehensive non-invasive respiratory support strategy. This article will help neonatal units in the US develop guidelines for LISA, provide optimal respiratory support for infants with respiratory distress syndrome, improve short- and long-term outcomes of preterm infants, and potentially decrease costs of NICU care.

Future of clinical trials in the delivery room: time for pragmatism

Despite increased amounts of research, most of the evidence that supports treatment of newborns in the delivery room is rated 'low' rather than 'high' quality. This assessment stems largely from a lack of evidence from clinical trials. When trials have been performed, the evidence has often been downgraded due to enrolment of small or poorly representative samples, and for lack of blinding of caregivers and outcome assessors. Delivery room trials present particular challenges when obtaining consent, enrolling participants, taking measures to limit bias and identifying appropriate outcome measures. We hope our suggestions as to how future delivery room trials could be more pragmatic will inform the design of large studies that are necessary to allow clinical practice to evolve.

European Consensus Guidelines on the Management of Respiratory Distress Syndrome: 2022 Update

Respiratory distress syndrome (RDS) care pathways evolve slowly as new evidence emerges. We report the sixth version of "European Guidelines for the Management of RDS" by a panel of experienced European neonatologists and an expert perinatal obstetrician based on available literature up to end of 2022. Optimising outcome for babies with RDS includes prediction of risk of preterm delivery, appropriate maternal transfer to a perinatal centre, and appropriate and timely use of antenatal steroids. Evidence-based lung-protective management includes initiation of non-invasive respiratory support from birth, judicious use of oxygen, early surfactant administration, caffeine therapy, and avoidance of intubation and mechanical ventilation where possible. Methods of ongoing non-invasive respiratory support have been further refined and may help reduce chronic lung disease. As technology for delivering mechanical ventilation improves, the risk of causing lung injury should decrease, although minimising time spent on mechanical ventilation by targeted use of postnatal corticosteroids remains essential. The general care of infants with RDS is also reviewed, including emphasis on appropriate cardiovascular support and judicious use of antibiotics as being important determinants of best outcome. We would like to dedicate this guideline to the memory of Professor Henry Halliday who died on November 12, 2022.These updated guidelines contain evidence from recent Cochrane reviews and medical literature since 2019. Strength of evidence supporting recommendations has been evaluated using the GRADE system. There are changes to some of the previous recommendations as well as some changes to the strength of evidence supporting recommendations that have not changed. This guideline has been endorsed by the European Society for Paediatric Research (ESPR) and the Union of European Neonatal and Perinatal Societies (UENPS).

New modes of surfactant delivery

The provision of exogenous surfactant to premature infants with respiratory distress syndrome has revolutionized the way we care for these patients, significantly improving survival and decreasing morbidity. Currently, the Intubate-SURfactant-Extubate (INSURE) to non-invasive ventilation method remains the standard method for surfactant delivery in the United States. However, the INSURE method requires intubation via direct visualization with a laryngoscope and possible need for sedation. Both carry significant risk to the patients, prompting the development of less invasive ways of safely and efficaciously providing surfactant to newborn infants. The present article reviews and describes the benefits and limitations of several of these alternative methods, including Less Invasive Surfactant Administration (LISA), Minimally Invasive Surfactant Therapy (MIST), via aerosolization, laryngeal mask airway (LMA), and direct nasopharyngeal deposition, focusing on assessment of clinical benefits and the level/risk of invasiveness.

Research in the Delivery Room: Can You Tell Me It's Evolution?

Many of the recommendations for newborn care in the delivery room (DR) are based on retrospective observational studies, preclinical studies of mannequins or animal models, and expert opinion. Conducting DR research is challenging. Many deliveries occur in fraught circumstances with little prior warning, making it difficult to get prospective consent from parents and buy-in from clinicians. Many DR interventions are difficult to mask for the purpose of a clinical trial and it is not easy to identify appropriate outcomes for studies that are sufficiently "short-term" that they are likely to be influenced by the intervention, yet sufficiently "long-term" to be considered clinically important. However, despite these challenges, much information has been accrued from clinical studies in recent years. In this article, we outline our experience of conducting clinical research in the DR. In our initial studies almost 20 years ago, we found wide variation in the equipment used both nationally and internationally, reflecting the paucity of evidence to support practice. This started a journey that has included many observational studies and randomized controlled trials that have attempted to refine how we care for newborn infants in the DR. Each has given further information and, inevitably, raised many more questions about the approach to caring for newborns in the DR.

A systematic review of surfactant delivery via laryngeal mask airway, pharyngeal instillation, and aerosolization: Methods, limitations, and outcomes

Less invasive surfactant administration methods without laryngoscopy and endotracheal catheterization include delivery via laryngeal mask airway, pharyngeal instillation, and aerosolization. These less invasive techniques are promising and have several advantages over INSURE (Intubation-Surfactant-Extubation) and thin catheter techniques. The objective of this review is to discuss the requisites, techniques, short-term outcomes, and adverse events associated with these methods.

Impact of early respiratory care for extremely preterm infants

Despite advances in neonatal intensive care, more than half of surviving infants born extremely preterm (EP; < 28 weeks' gestation) develop bronchopulmonary dysplasia (BPD). Prevention of BPD is critical because of its associated mortality and morbidity, including adverse neurodevelopmental outcomes and respiratory health in later childhood and beyond. The respiratory care of EP infants begins before birth, then continues in the delivery room and throughout the primary hospitalization. This chapter will review the evidence for interventions after birth that might improve outcomes for infants born EP, including the timing of umbilical cord clamping, strategies to avoid or minimize exposure to mechanical ventilation, modes of mechanical ventilation and non-invasive respiratory support, oxygen saturation targets, postnatal corticosteroids and other adjunct therapies.

Pulmonary surfactant: a unique biomaterial with life-saving therapeutic applications

Pulmonary surfactant is a complex lipoprotein mixture secreted into the alveolar lumen by type 2 pneumocytes, which is composed by tens of different lipids (approximately 90% of its entire mass) and surfactant proteins (approximately 10% of the mass). It is crucially involved in maintaining lung homeostasis by reducing the values of alveolar liquid surface tension close to zero at end-expiration, thereby avoiding the alveolar collapse, and assembling a chemical and physical barrier against inhaled pathogens. A deficient amount of surfactant or its functional inactivation is directly linked to a wide range of lung pathologies, including the neonatal respiratory distress syndrome. This paper reviews the main biophysical concepts of surfactant activity and its inactivation mechanisms, and describes the past, present and future roles of surfactant replacement therapy, focusing on the exogenous surfactant preparations marketed worldwide and new formulations under development. The closing section describes the pulmonary surfactant in the context of drug delivery. Thanks to its peculiar composition, biocompatibility, and alveolar spreading capability, the surfactant may work not only as a shuttle to the branched anatomy of the lung for other drugs but also as a modulator for their release, opening to innovative therapeutic avenues for the treatment of several respiratory diseases.

Randomised study of heart rate measurement in preterm newborns with ECG plus pulse oximetry versus oximetry alone

AIM

To determine whether the IntelliVue monitor (ECG plus Masimo pulse oximeter (PO)) displays heart rate (HR) at birth more quickly than Nellcor PO (PO alone) among infants of 29-35 weeks' gestational age.

METHODS

Unmasked parallel group randomised (1:1) study.

RESULTS

We planned to enrol 100 infants; however, the study was terminated due to the COVID-19 pandemic when 39 infants had been enrolled (17 randomised to IntelliVue, 22 to Nellcor). We found no differences between the groups in the time to first HR display (median (IQR) IntelliVue ECG 49 (33, 71) vs Nellcor 47 (37, 86) s, p>0.999), in the proportion who had a face mask applied for breathing support, or in the time at which it was applied. Infants monitored with IntelliVue were handled more frequently and for longer.

CONCLUSION

IntelliVue ECG did not display HR more quickly than Nellcor PO in preterm infants. We found no differences in the rate of or time to intervention between groups. Our study was terminated early so these findings should be interpreted with caution.

TRIAL REGISTRATION NUMBER

ISRCTN16473881.