Technique for intrapartum administration of surfactant without requirement for an endotracheal tube

Laryngeal mask airway surfactant administration for prevention of morbidity and mortality in preterm infants with or at risk of respiratory distress syndrome

BACKGROUND

Laryngeal mask airway surfactant administration (S-LMA) has the potential benefit of surfactant administration whilst avoiding endotracheal intubation and ventilation, ventilator-induced lung injury and bronchopulmonary dysplasia (BPD).

OBJECTIVES

To evaluate the benefits and harms of S-LMA either as prophylaxis or treatment (rescue) compared to placebo, no treatment, or intratracheal surfactant administration via an endotracheal tube (ETT) with the intent to rapidly extubate (InSurE) or extubate at standard criteria (S-ETT) or via other less-invasive surfactant administration (LISA) methods on morbidity and mortality in preterm infants with or at risk of respiratory distress syndrome (RDS).

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, and three trial registries in December 2022.

SELECTION CRITERIA

Randomised controlled trials (RCTs), cluster- or quasi-RCTs of S-LMA compared to placebo, no treatment, or other routes of administration (nebulised, pharyngeal instillation of surfactant before the first breath, thin endotracheal catheter surfactant administration or intratracheal surfactant instillation) on morbidity and mortality in preterm infants at risk of RDS. We considered published, unpublished and ongoing trials.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion and extracted data. We used GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included eight trials (seven new to this update) recruiting 510 newborns. Five trials (333 infants) compared S-LMA with surfactant administration via ETT with InSurE. One trial (48 infants) compared S-LMA with surfactant administration via ETT with S-ETT, and two trials (129 infants) compared S-LMA with no surfactant administration. We found no studies comparing S-LMA with LISA techniques or prophylactic or early S-LMA. S-LMA versus surfactant administration via InSurE S-LMA may have little or no effect on the composite outcome of death or BPD at 36 weeks' postmenstrual age (risk ratio (RR) 1.50, 95% confidence interval (CI) 0.27 to 8.34, I 2 = not applicable (NA) as 1 study had 0 events; risk difference (RD) 0.02, 95% CI -0.07 to 0.10; I 2 = 0%; 2 studies, 110 infants; low-certainty evidence). There may be a reduction in the need for mechanical ventilation at any time (RR 0.53, 95% CI 0.36 to 0.78; I 2 = 27%; RD -0.14, 95% CI -0.22 to -0.06, I 2 = 89%; number needed to treat for an additional beneficial outcome (NNTB) 7, 95% CI 5 to 17; 5 studies, 333 infants; low-certainty evidence). However, this was limited to four studies (236 infants) using analgesia or sedation for the InSurE group. There was little or no difference for air leak during first hospitalisation (RR 1.39, 95% CI 0.65 to 2.98; I 2 = 0%; 5 studies, 333 infants (based on 3 studies as 2 studies had 0 events); low-certainty evidence); BPD among survivors to 36 weeks' PMA (RR 1.28, 95% CI 0.47 to 3.52; I 2 = 0%; 4 studies, 264 infants (based on 3 studies as 1 study had 0 events); low-certainty evidence); or death (all causes) during the first hospitalisation (RR 0.28, 95% CI 0.01 to 6.60; I 2 = NA as 2 studies had 0 events; 3 studies, 203 infants; low-certainty evidence). Neurosensory disability was not reported. Intraventricular haemorrhage ( IVH) grades III and IV were reported among the study groups (1 study, 50 infants). S-LMA versus surfactant administration via S-ETT No study reported death or BPD at 36 weeks' PMA. S-LMA may reduce the use of mechanical ventilation at any time compared with S-ETT (RR 0.47, 95% CI 0.31 to 0.71; RD -0.54, 95% CI -0.74 to -0.34; NNTB 2, 95% CI 2 to 3; 1 study, 48 infants; low-certainty evidence). We are very uncertain whether S-LMA compared with S-ETT reduces air leak during first hospitalisation (RR 2.56, 95% CI 0.11 to 59.75), IVH grade III or IV (RR 2.56, 95% CI 0.11 to 59.75) and death (all causes) during the first hospitalisation (RR 0.17, 95% CI 0.01 to 3.37) (1 study, 48 infants; very low-certainty evidence). No study reported BPD to 36 weeks' PMA or neurosensory disability. S-LMA versus no surfactant administration Rescue surfactant could be used in both groups. There may be little or no difference in death or BPD at 36 weeks (RR 1.65, 95% CI 0.85 to 3.22; I 2 = 58%; RD 0.08, 95% CI -0.03 to 0.19; I 2 = 0%; 2 studies, 129 infants; low-certainty evidence). There was probably a reduction in the need for mechanical ventilation at any time with S-LMA compared with nasal continuous positive airway pressure without surfactant (RR 0.57, 95% CI 0.38 to 0.85; I 2 = 0%; RD -0.24, 95% CI -0.40 to -0.08; I 2 = 0%; NNTB 4, 95% CI 3 to 13; 2 studies, 129 infants; moderate-certainty evidence). There was little or no difference in air leak during first hospitalisation (RR 0.65, 95% CI 0.23 to 1.88; I 2 = 0%; 2 studies, 129 infants; low-certainty evidence) or BPD to 36 weeks' PMA (RR 1.65, 95% CI 0.85 to 3.22; I 2 = 58%; 2 studies, 129 infants; low-certainty evidence). There were no events in either group for death during the first hospitalisation (1 study, 103 infants) or IVH grade III and IV (1 study, 103 infants). No study reported neurosensory disability.

AUTHORS' CONCLUSIONS

In preterm infants less than 36 weeks' PMA, rescue S-LMA may have little or no effect on the composite outcome of death or BPD at 36 weeks' PMA. However, it may reduce the need for mechanical ventilation at any time. This benefit is limited to trials reporting the use of analgesia or sedation in the InSurE and S-ETT groups. There is low- to very-low certainty evidence for no or little difference in neonatal morbidities and mortality. Long-term outcomes are largely unreported. In preterm infants less than 32 weeks' PMA or less than 1500 g, there are insufficient data to support or refute the use of S-LMA in clinical practice. Adequately powered trials are required to determine the effect of S-LMA for prevention or early treatment of RDS in extremely preterm infants. S-LMA use should be limited to clinical trials in this group of infants.

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.

Surfactant administration in preterm babies (28-36 weeks) with respiratory distress syndrome: LISA versus InSurE, an open-label randomized controlled trial

INTRODUCTION

INtubate-SURfactant-Extubate (InSurE) approach is traditional method of surfactant delivery in preterm neonates with respiratory distress syndrome (RDS). Newer, less invasive surfactant administration (LISA) techniques lessen the need for mechanical ventilation and its adverse consequences. Evidence on the favorable effects of LISA can't be extrapolated from developed to developing countries. Aim of study is to compare the effectiveness of InSurE and LISA.

OBJECTIVES

Primary outcome was to find need of intubation and mechanical ventilation within 72 h of birth. Neonates were followed until discharge/death for adverse events and complications. MATERIALS AND METHODS: Open-label randomized controlled trial (RCT) was conducted at tertiary neonatal intensive care unit. Preterm neonates with diagnosis of RDS were randomized in two groups (InSurE or LISA) to receive surfactant soon after birth. Nasal intermittent positive pressure ventilation (NIPPV) was used as primary mode of respiratory support.

RESULTS

A total of 150 neonates were analyzed (75 in each group). Insignificant statistical difference was seen in the need for intubation and mechanical ventilation within 72 h of birth between the two groups (InSurE, 30 [40%] and LISA, 30 [40%], relative risk 1.0, 95% confidence interval 0.68-1.48). Twelve percent (n = 9, LISA group) and 14.6% (n = 11 InSurE group) had adverse events during the procedure. Also, we observed insignificant statistical difference in the rates of major complications or duration of respiratory support, hospital stay, and mortality.

CONCLUSION

LISA and InSurE are equally effectiSpontaneously breathing pretermve for surfactant administration in the treatment of RDS, when NIPPV is the primary mode of respiratory support. More RCTs are required to compare the efficacy and long-term outcomes of LISA with InSurE.

Less invasive surfactant administration via infant feeding tube versus InSurE method in preterm infants: a randomized control trial

There is growing evidence that less invasive surfactant administration (LISA) is a better alternative to the standard Intubate-surfactant-extubate (InSurE) procedure in spontaneously breathing preterm infants with RDS. The infant feeding tube is easily available and cost-effective in comparison to special catheters used for surfactant administration in various studies on LISA and cost-effective health care is the need of the hour for countries like ours which are Low and middle-income countries(LMICs).The present study was planned to compare the total duration of respiratory support in preterm babies between 26 to 34 weeks of gestation with RDS requiring surfactant therapy administered by LISA technique using an infant feeding tube or InSurE method. In this unblinded randomised controlled trial, 150 infants were allocated to LISA (n = 74) or InSurE group (n = 76). An 8F feeding tube was used for surfactant delivery in the LISA group. The primary outcome was the total duration of respiratory support required and secondary outcomes included the proportion of babies developing BPD, IVH, PDA, NEC, ROP, air leaks, CPAP failure, and those requiring a repeat dose of surfactant along with the duration of hospitalization, time to regain birth weight and Death. The baseline variables including birth weight and gestation age were similar in the two groups. Nearly 27% of the mothers did not receive any dose of antenatal steroids (ANS) while around 37% of the mothers received complete course of ANS. A high proportion of babies (57%) were delivered by cesarean section. Intrapharyngeal reflux was significantly more in babies who received surfactant with the LISA method in comparison to InSurE technique (32% v/s 3%, p < 0.001). There was no statistically significant difference in the primary outcome of the total duration of respiratory support in both groups with a median duration of 120 h, 95% CI (69-235), and p = 0.618. The need for invasive mechanical ventilation was significantly lower in the LISA group (p = 0.017) with RR (95% CI) 0.498 (0.259-0.958). The rate of CPAP failure was significantly lower in the LISA group (p = 0.005) with RR (95% CI) 0.55 (0.34-0.89). In this study, the total duration of hospital stay was reduced in the LISA group (19 days) compared to InSurE group (26 days), although the same was not statistically significant. LISA with an 8F feeding tube is feasible and an effective strategy for surfactant administration which resulted in a significant reduction in CPAP failure and the need for invasive mechanical ventilation.Trial registration: www.ctri.nic.in id CTRI/2020/05/025360. Trial was registered at CTRI on 26/05/2020. First case of trial was enrolled on 28/05/2020.

Surfactant Replacement Therapy: What’s the New Future?

Surfactant replacement therapy (SRT) can be lifesaving for preterm babies with respiratory distress because of surfactant deficiency. Attempts have been made over the last two decades to make surfactant administration as smooth and as nontraumatic as possible. Lesser invasive techniques, such as less invasive surfactant administration, minimally invasive surfactant therapy, intrapartum pharyngeal surfactant therapy, and the laryngeal mask airway, are preferred over invasive techniques like intubate surfactant extubation to reduce trauma and peridosing adverse effects. However, at present, aerosolized surfactant (AS) via nebulization remains the only truly noninvasive method of SRT. Many animal and human studies have shown promising results with the use of AS with similar clinical effects to an instilled surfactant with greater safety potential. But still AS has not been adapted to routine neonatal care. There is still scope for studies to further strengthen the role of AS. Also, SRT is a constantly changing field with new innovations revolutionizing and replacing old techniques.

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.

Alternative Methods of Surfactant Administration in Preterm Infants with Respiratory Distress Syndrome: State of the Art

For preterm infants with respiratory distress syndrome, delivery of surfactant via brief intubation (INtubate, SURfactant, Extubate; InSurE) has been the standard technique of surfactant administration. However, this method requires intubation and positive pressure ventilation. It is thought that even the short exposure to positive pressure inflations may be enough to initiate the cascade of events that lead to lung injury in the smallest neonates. In an effort to avoid tracheal intubation and positive pressure ventilation, several alternative and less invasive techniques of exogenous surfactant administration have been developed over the years. These have been investigated in clinical studies, including randomized clinical trials, and have demonstrated advantages such as a decrease in the need for mechanical ventilation and incidence of bronchopulmonary dysplasia. These newer techniques of surfactant delivery also have the benefit of being easier to perform. Surfactant delivery via pharyngeal instillation, laryngeal mask, aerosolization, and placement of a thin catheter are being actively pursued in research. We present a contemporary review of surfactant administration for respiratory distress syndrome via these alternative methods in the hope of guiding physicians in their choices for surfactant application in the neonatal intensive care unit.

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.

Less Invasive Surfactant Administration (LISA) vs. Intubation Surfactant Extubation (InSurE) in Preterm Infants with Respiratory Distress Syndrome: A Pilot Randomized Controlled Trial

OBJECTIVE

There has been an endeavor in recent years, to administer surfactant by minimally invasive techniques to neonates with surfactant deficiency. The objective of this study was to compare the need for intubation and mechanical ventilation after surfactant delivery, using Less Invasive Surfactant Administration (LISA) technique and Intubation SURfactant Extubation (InSurE), in preterm infants with respiratory distress syndrome (RDS).

METHODS

We conducted a pilot randomized control trial (RCT) at a tertiary care center over a period of 18 months. Preterm neonates with RDS (gestational age 28-36 weeks) were randomized to receive surfactant within 6 h of birth by InSurE or LISA. The primary outcome was need for intubation and mechanical ventilation within 72 h of birth. Infants were followed until discharge for adverse events and complications.

RESULTS

A total of 40 infants were analyzed (20 in each group). There was no difference in the need for intubation and mechanical ventilation within 72 h of birth between the two groups [InSurE, 6 (30%) and LISA, 6 (30%), relative risk 1.0, 95% confidence interval 0.51-1.97]. About 15% of infants in both groups had adverse events during the procedure. There was no statistically significant difference in the rates of major complications or duration of respiratory support, hospital stay and mortality.

CONCLUSION

We found LISA to be feasible and equally effective as InSurE for surfactant administration in the treatment of RDS in preterm infants. Future larger RCTs are required to compare the efficacy and long-term outcomes of LISA with the standard invasive methods of surfactant administration.

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.

The Comparison of LISA and INSURE techniques in term of neonatal morbidities and mortality among premature infants

BACKGROUND AND AIM OF THE WORK

Respiratory distress syndrome (RDS) is the most common cause of respiratory failure among premature infants. The most important choice for the treatment of  RDS is still exogenous surfactant replacement therapy and respiratory support. Today, there are some different surfactant applying techniques. In this study, we aimed to evaluate the effects of the surfactant administration techniques in premature infants less than 33 weeks of gestational age.

METHODS

The medical data were collected retrospectively from the medical records of Baskent University, Konya Training and Research Hospital between 2010 and 2016.  The patient divided into two subgroups as Less Invasive Surfactant Administration (LISA) group (n: 35) and Intubation- Surfactant administration and rapid Extubation (INSURE) group (n: 30). Two surfactant administration techniques were evaluated on the neonatal morbidities and mortality among premature infants.

RESULTS

There were no significant differences in maternal and neonatal characteristics between the two groups. Duration on the nasal continues positive airway pressure (nCPAP) is significantly higher in the LISA group as compared with the INSURE group (p<0.001).  And also between two groups, there were no significant differences in term of neonatal mortality and morbidities.

CONCLUSION

The technique of the surfactant administration has no effect on the postnatal morbidities. LISA method is safe and effective as much as INSURE method, which is still a good alternative in centers with lack of experience about LISA. We need to perform studies that have larger sample size and prospective randomized controlled trials.

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

INTRODUCTION

Many preterm infants develop respiratory distress syndrome (RDS), a condition characterised by a relative lack of surfactant. Endotracheal surfactant therapy revolutionised the care of preterm infants in the 1990s. However, supporting newborns with RDS with continuous positive airway pressure (CPAP) and reserving endotracheal surfactant for those who develop respiratory failure despite CPAP yield better results than intubating all infants for surfactant. Half of preterm infants born before 29 weeks gestation initially managed with CPAP are intubated for surfactant. Intubation is difficult to learn and associated with adverse effects. Surfactant administration into the oropharynx has been reported in preterm animals and humans and may be effective. We wished to determine whether giving oropharyngeal surfactant at birth reduces the rate of endotracheal intubation for respiratory failure in preterm infants within 120 hours of birth.

METHODS AND ANALYSIS

Prophylactic Oropharyngeal surfactant for Preterm infants: A Randomised Trial (POPART, Eudract No. 2016-004198-41) is an investigator-led, unblinded, multicentre, randomised, parallel group, controlled trial. Infants are eligible if born at a participating centre before 29 weeks gestational age (GA) and there is a plan to offer intensive care. Infants are excluded if they have major congenital anomalies. Infants are randomised at birth to treatment with oropharyngeal surfactant (120 mg vial <26 weeks GA stratum; 240 mg vial 26-28⁺⁶ weeks GA stratum) in addition to CPAP or CPAP alone. The primary outcome is intubation within 120 hours of birth, for bradycardia and/or apnoea despite respiratory support in the delivery room or respiratory failure in the intensive care unit. Secondary outcomes include incidence of mechanical ventilation, endotracheal surfactant use, chronic lung disease and death before hospital discharge.

ETHICS AND DISSEMINATION

Approval for the study has been granted by the Research Ethics Committees at the National Maternity Hospital, Dublin, Ireland (EC31.2016) and at each participating site. The trial is being conducted at nine centres in six European countries. The study results will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

2016-004198-41; Pre-results.

Less invasive surfactant administration: best practices and unanswered questions

PURPOSE OF REVIEW

The purpose of this review is to describe current concepts in the field of Less Invasive Surfactant Administration (LISA). The use of continuous positive airway pressure (CPAP) has become standard for the treatment of premature infants with respiratory problems throughout the world. However, if CPAP fails, technologies like LISA are needed that can combine surfactant delivery and spontaneous breathing with the support of noninvasive modes of ventilation.

RECENT FINDINGS

LISA with thin catheters has been in use in Germany for more than 15 years. In the last 5 years, there was substantial interest in this method around the world. Randomized studies and recent metaanalyses indicate that the LISA technique helps to avoid mechanical ventilation especially in emerging respiratory distress syndrome (RDS). LISA is also associated with improved outcomes of preterm infants, specifically in the prevention of bronchopulmonary dysplasia (BPD) and intracranial hemorrhage (ICH). By now, a variety of different LISA catheters, devices and techniques have been described. However, most of the technologies are still connected with the unpleasant experience of laryngoscopy for the affected infants, so that the search for even less invasive techniques, for example, surfactant application by nebulization, goes on.

SUMMARY

Maintenance of spontaneous breathing with support by the LISA technique holds big promise in the care of preterm infants. Patient comfort and lower complication rates are strong arguments to further investigate and promote the LISA approach. Open questions include exact indications for different patient groups, the usefulness of devices/catheters that have recently been built for the LISA technique and -- perhaps most urgently -- the issue of analgesia/sedation during the procedure. Studies on long-term outcome after LISA are under way.

Delivery room emergencies: Respiratory emergencies in the DR

The majority of newborns transition to extra uterine life without support. However, respiratory emergencies in the delivery room are a common occurrence. Whilst some situations are predictable e.g. the anticipated birth of an extremely preterm infant, others are less so. In this chapter we address the most frequent scenarios that result in delivery room respiratory emergencies and discuss the latest recommendations for their management. We outline the need for a trained resuscitation team and appropriate equipment to provide respiratory support at every birth. We address the basic care that all infants should receive, the detailed application of non-invasive ventilation and the use of advanced airway techniques. We discuss the unique challenges presented by extreme prematurity including umbilical cord management, use of supplemental oxygen, initial modes of respiratory support and surfactant delivery. We will explore optimal techniques in the management of infants with lung hypoplasia, pneumothorax and meconium aspiration.

Cerebral oxygenation associated with INSURE versus LISA procedures in surfactant-deficient newborn piglet RDS model

BACKGROUND

Nasal continuous-positive airway pressure (nCPAP) with the INSURE (INtubation-SURfactant-Extubation) or LISA (Less-Invasive Surfactant Administration) procedures are increasingly being chosen as the initial treatment for neonates with surfactant deficiency. Our objective was to compare the effects on cerebral oxygenation of different methods for surfactant administration: INSURE and LISA, using a nasogastric tube (NT) or a LISAcath® catheter, in spontaneously breathing SF-deficient newborn piglets.

METHODS

Eighteen newborn piglets with SF-deficient lung injury produced by repetitive bronchoalveolar lavages were randomly assigned to INSURE, LISA-NT, or LISAcath® groups. We assessed pulmonary (gas exchange, lung mechanics, lung histology) and hemodynamic (mean arterial blood pressure, heart rate) changes, cerebral oxygenation (cTOI) and cerebral fractional tissue extraction (cFTOE), with near-infrared spectroscopy, carotid blood flow and brain histology.

RESULTS

SF-deficient piglets developed respiratory distress (F_iO2  = 1, pH <7.2, P_aCO2 >70 mmHg, P_aO2 <70 mmHg, C_dyn <0.5 mL/cmH₂ O/kg). Rapid improvements in pulmonary status were observed in all surfactant-treated groups without hemodynamic alterations. In the INSURE group, a transient decrease in cTOI occurred during and immediately after surfactant administration, while cTOI only decreased during surfactant administration in the LISA-NT group and did not change significantly in the LISAcath® group. Brain injury scores were low in all surfactant-treated groups.

CONCLUSION

In spontaneously breathing SF-deficient newborn piglets, short-lasting decreases in cerebral oxygenation are associated with surfactant administration by the INSURE method or LISA using an NT, while no cerebral oxygenation changes occurred with LISA using a LISAcath®. Notably, none of treatments studied seems to have a negative impact on the neonatal brain.

The use of less invasive surfactant administration (LISA) in the United States with review of the literature

BACKGROUND

The majority of extremely low gestational age neonates undergo intubation for surfactant therapy. Less invasive surfactant administration (LISA) uses a thin catheter inserted into the trachea to deliver the surfactant. During the procedure, the infant is breathing spontaneously while supported with continuous positive airway pressure. Although LISA is widely adapted in Europe and Australia, the rate of LISA use in the United States is unknown.

STUDY DESIGN

The aim of this study is to evaluate the use of LISA in the US. A web-based survey was distributed via SurveyMonkey to 2550 neonatologists from AAP's SoNPM mailing list.

RESULTS

Of the 472 neonatologists who answered the survey, 15% used LISA either as a part of routine care (8%) or as part of research (7%).

CONCLUSION

Unlike several regions of Europe, LISA is not widely used in the US. Future studies should address ambiguities regarding infant selection, procedure training and "roadblocks" to its broader application.

Novel Surfactant Administration Techniques: Will They Change Outcome?

Traditionally, surfactant has been administered to preterm infants with respiratory distress syndrome via an endotracheal tube and in conjunction with mechanical ventilation. However, negative consequences of mechanical ventilation such as pneumothorax and bronchopulmonary dysplasia are well known. In order to provide the benefits of surfactant administration without the negative effects of mechanical ventilation, several methods of less invasive surfactant administration have been developed. These methods include InSurE (intubate, surfactant, extubate), pharyngeal administration, laryngeal mask administration, aerosolized surfactant administration, and thin catheter administration (TCA). Of these, TCA has been studied most extensively and holds the most promise as a less invasive and effective mode of surfactant administration to preterm infants. Further studies will aid in determining which patients would benefit most from less invasive surfactant administration.

Laryngeal Mask Airway for Surfactant Administration in Neonates: A Randomized, Controlled Trial

OBJECTIVE

To determine if preterm infants with moderate respiratory distress syndrome on continuous positive airway pressure (CPAP) who received surfactant via a laryngeal mask airway (LMA) would have a decreased rate of intubation and mechanical ventilation compared with those on CPAP who did not receive surfactant.

STUDY DESIGN

In this prospective, multicenter, randomized controlled trial, 103 premature infants 28^0/7-35^6/7 weeks gestation, ≥1250 g and ≤36 hours old on CPAP requiring fraction of inspired oxygen 0.30-0.40 were assigned to receive surfactant administered through an LMA then placed back on CPAP (LMA group) or maintained on CPAP with no surfactant administered (control group). The primary outcome was treatment failure necessitating intubation and mechanical ventilation in the first 7 days of life.

RESULTS

Surfactant administration through an LMA (n = 50) significantly decreased the rate of intubation and mechanical ventilation compared with controls (n = 53): 38% vs 64%, respectively, OR 0.30 (95% CI 0.13, 0.70), P = .006, number needed to treat: 4). There were no serious adverse events associated with placement of the LMA or surfactant administration.

CONCLUSIONS

In premature neonates with moderate respiratory distress syndrome, surfactant administered through an LMA decreased the rate of intubation and mechanical ventilation. This intervention may have significant impact on clinical care in both high and low resource settings.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01116921.

Oropharyngeal surfactant can improve initial stabilisation and reduce rescue intubation in infants born below 25 weeks of gestation

AIM

Minimally aggressive and easily performed techniques that facilitate spontaneous respiratory stabilisation are required to reduce rescue intubation in extremely premature infants. This study evaluated the feasibility and safety of administering surfactant into the pharynx of infants born at <25 weeks immediately after birth.

METHODS

This study of 19 infants was conducted from January 2013 to June 2014 in a tertiary perinatal centre in Prague. We administered 1.5 mL of Curosurf as a bolus into the pharynx and simultaneously performed a sustained inflation manoeuvre (SIM). The extent of the interventions, death and severe neonatal morbidity in the study group were compared with 20 controls born before the study period and 20 born after it.

RESULTS

All infants received oropharyngeal surfactant within the median (interquartile range) time of 40 seconds (25-75) after cord camping. The surfactant had to be suctioned in one infant because of upper airway obstruction. Although more subsequent surfactant was administered in the study group, significantly fewer study period infants required intubation than the before and after controls (16% versus 75% and 58%, respectively, p < 0.01).

CONCLUSION

Oropharyngeal surfactant with simultaneous SIM was feasible and safe and reduced the need for delivery room intubation in these fragile infants.

Update of minimally invasive surfactant therapy

To date, preterm infants with respiratory distress syndrome (RDS) after birth have been managed with a combination of endotracheal intubation, surfactant instillation, and mechanical ventilation. It is now recognized that noninvasive ventilation (NIV) such as nasal continuous positive airway pressure (CPAP) in preterm infants is a reasonable alternative to elective intubation after birth. Recently, a meta-analysis of large controlled trials comparing conventional methods and nasal CPAP suggested that CPAP decreased the risk of the combined outcome of bronchopulmonary dysplasia or death. Since then, the use of NIV as primary therapy for preterm infants has increased, but when and how to give exogenous surfactant remains unclear. Overcoming this problem, minimally invasive surfactant therapy (MIST) allows spontaneously breathing neonates to remain on CPAP in the first week after birth. MIST has included administration of exogenous surfactant by intrapharyngeal instillation, nebulization, a laryngeal mask, and a thin catheter. In recent clinical trials, surfactant delivery via a thin catheter was found to reduce the need for subsequent endotracheal intubation and mechanical ventilation, and improves short-term respiratory outcomes. There is also growing evidence for MIST as an alternative to the INSURE (intubation-surfactant-extubation) procedure in spontaneously breathing preterm infants with RDS. In conclusion, MIST is gentle, safe, feasible, and effective in preterm infants, and is widely used for surfactant administration with noninvasive respiratory support by neonatologists. However, further studies are needed to resolve uncertainties in the MIST method, including infant selection, optimal surfactant dosage and administration method, and need for sedation.

A randomized controlled trial of the laryngeal mask airway for surfactant administration in neonates

OBJECTIVE

To compare the short-term efficacy of surfactant administration by laryngeal mask airway versus endotracheal tube.

METHODS

Preterm infants (28-35 weeks of gestational age), weighing 1kg or more, with respiratory distress syndrome, requiring nasal continuous positive airway pressure, with increased respiratory effort and/or fraction of inspired oxygen (FiO₂)≥0.40 to maintain oxygen saturation 91-95%, were randomized to receive surfactant by LMA following nCPAP or by ETT following mechanical ventilation (MV). The primary outcome was a clinical response defined as FiO₂≤0.30 three hours after surfactant. Secondary outcomes for LMA group were: need of surfactant retreatment during the first 24h, MV requirement, and presence of surfactant in gastric content.

RESULTS

Forty-eight patients were randomized; 26 in the LMA group and 22 in the ETT group. Six of 26 patients (23%) in the LMA group and five of 22 patients (22.7%) in the ETT group did not meet the primary outcome (p=0.977). Fourteen (53.8%) of the LMA patients were not intubated nor ventilated; 12 (46.1%) were ventilated: for surfactant failure (23%), for nCPAP failure (11.5%), and for late complications (11.5%). Groups were similar regarding prenatal status, birth conditions, and adverse events. No significant gastric content was found in 61.5% of the LMA patients. Oxygen and second dose surfactant requirements, arterial/alveolar ratio, and morbidities were similar among groups.

CONCLUSIONS

Surfactant administration by LMA showed short-term efficacy, with similar supplementary oxygen need compared to surfactant by ETT, and lower MV requirement. Further studies with larger sample size are necessary to confirm these results.

The evolution of modern respiratory care for preterm infants

Preterm birth rates are rising, and many preterm infants have breathing difficulty after birth. Treatments for infants with prolonged breathing difficulty include oxygen therapy, exogenous surfactant, various modes of respiratory support, and postnatal corticosteroids. In this Series paper, we review the history of neonatal respiratory care and its effect on long-term outcomes, and we outline the future direction of the research field. The delivery and monitoring of oxygen therapy remains controversial, despite being in use for more than 50 years. Exogenous surfactant replacement has been used for 25 years and has dramatically reduced mortality and morbidity, but more research on when and how it is administered is needed. Methods and techniques of neonatal respiratory support are evolving. Clinicians are moving away from routine intubation and ventilation, and new modes of non-invasive support are being investigated. Postnatal corticosteroids have a limited role in infants with evolving bronchopulmonary dysplasia, but more research is needed to identify the best timing, type, dose, and method of administration. Despite advances in neonatal care in the past 50 years, bronchopulmonary dysplasia, with all its adverse short-term and long-term consequences, is still a serious problem in neonatal care. The challenge remains to support breathing in preterm infants, with special attention to risk factors in the subpopulation of infants that are at highest risk of bronchopulmonary dysplasia, without damaging their lungs or adversely affecting their long-term health.

Effect of Surfactant Therapy Using Orogastric Tube for Tracheal Catheterization in Preterm Newborns with Respiratory Distress

OBJECTIVE

To assess the outcome of a modified method of Minimally Invasive Surfactant Therapy (MIST) therapy where an orogastric tube was used for tracheal catherization to deliver surfactant in preterm newborns less than 34 wk of gestation with respiratory distress syndrome (RDS).

METHODS

A single centre, prospective observational study was conducted to enroll eligible inborn preterm neonates with gestation age more than 24 wk but less than 34 wk and suffering from RDS to receive surfactant using MIST. Results were compared with a historical cohort of preterms who received surfactant with InSurE (Intubate, Surfactant, Extubate) technique.

RESULTS

Sixty four cases in the modified MIST group were compared with a historic cohort of 68 cases in the InSurE group. There were no differences in the requirement of intubation and mechanical ventilation (MV) in the first 72 h but the duration of MV and continuous positive airway pressure (CPAP) were significantly less in modified MIST group. Other neonatal morbidities and mortality rates were similar in either of the groups.

CONCLUSIONS

The modified MIST technique is an effective method for the treatment of RDS in preterms with better clinical efficacy and comparable outcomes than the more invasive InSurE procedure and deserves further evaluation.

Less Invasive Surfactant Administration Reduces the Need for Mechanical Ventilation in Preterm Infants: A Meta-Analysis

Neonatal respiratory distress syndrome due to surfactant deficiency is associated with high morbidity and mortality in preterm infants, and the use of less invasive surfactant administration (LISA) has been increasingly studied. This meta-analysis found that LISA via thin catheter significantly reduced the need for mechanical ventilation within the first 72 hours (relative risk [RR] = 0.677; P = .021), duration of mechanical ventilation (difference in means [MD] = −39.302 hours; P < .001), duration of supplemental oxygen (MD = −68.874 hours; P < .001), and duration of nasal continuous positive airway pressure (nCPAP; MD = −28.423 hours; P = .010). A trend toward a reduction in the incidence of bronchopulmonary dysplasia was observed (RR = 0.656; P = .141). No significant difference in overall mortality, incidence of pneumothorax, or successful first attempts was observed. LISA via thin catheter significantly reduces the need for mechanical ventilation within the first 72 hours as well as the duration of mechanical ventilation, supplemental oxygen, and nCPAP. LISA via thin catheter appears promising in improving preterm infant outcomes.

Minimally Invasive Surfactant Therapy and Noninvasive Respiratory Support

Respiratory distress syndrome (RDS) caused by surfactant deficiency is major cause for neonatal mortality and short- and long-term morbidity of preterm infants. Continuous positive airway pressure and other modes of noninvasive respiratory support and intubation and positive pressure ventilation with surfactant therapy are efficient therapies for RDS. Because continuous positive airway pressure can fail in severe surfactant deficiency, and because traditional surfactant therapy requires intubation and positive pressure ventilation, this entails a risk of lung injury. Several strategies to combine noninvasive respiratory therapy with minimally invasive surfactant therapy have been described. Available data suggest that those strategies may improve outcome of premature infants with RDS.

Ancillary therapies to enhance success of non-invasive modes of respiratory support - Approaches to delivery room use of surfactant and caffeine?

During recent decades, non-invasive respiratory support has become popular for treating neonates with respiratory failure. Several prospective randomized controlled trials have been performed to compare use of continuous positive airway pressure (CPAP) as primary respiratory support in preterm infants with respiratory distress syndrome (RDS) to endotracheal intubation, mechanical ventilation and surfactant therapy. Systematic reviews of these studies suggest that routine CPAP at delivery is efficacious in decreasing bronchopulmonary dysplasia (BPD), death, or both. This led to the recommendation to consider CPAP to avoid endotracheal intubation. As surfactant therapy is known to reduce BPD and death, several ways to combine CPAP with surfactant have been described. With the increasing use of CPAP immediately after birth, the early use of caffeine to stimulate respiration has become a point of discussion. This review focuses on different modes of surfactant application during CPAP and on the early use of caffeine as ancillary therapies to enhance CPAP success.

Less invasive beractant administration in preterm infants: a pilot study

OBJECTIVES

The aims of this study were to assess the efficacy and feasibility of a new, less invasive surfactant administration technique for beractant replacement using a specifically designed cannula in preterm infants born at <32 weeks of gestation and to compare short- and long-term outcomes between this approach and standard treatment, consisting of intubation, administration of surfactant and early extubation to nasal continuous positive airway pressure.

METHOD

This was a single-center, prospective, open-label, non-randomized, controlled pilot study with an experimental cohort of 30 patients treated with less invasive surfactant administration and a retrospective control group comprising the 30 patients most recently treated with the standard approach. Beractant (4 ml/kg) was administered as an exogenous surfactant in both groups if patients on nasal continuous positive airway pressure during the first three days of life were in need of more than 30% FiO2. Clinicaltrials.gov: NCT02611284.

RESULTS

In the group with less invasive surfactant administration, beractant was successfully administered in all patients. Thirteen patients (43.3%) in the group with less invasive surfactant administration required invasive mechanical ventilation for more than 1 hour during the first 3 days of life, compared with 22 (73%) in the control group (p<0.036). The rate of requiring invasive mechanical ventilation for more than 48 hours was similar between the infants in the two groups (46% vs. 40%, respectively). There were no differences in other outcomes.

CONCLUSION

The administration of beractant (4 ml/kg) using a less invasive surfactant administration technique with a specifically designed cannula for administration is feasible. Moreover, early invasive mechanical ventilation exposure is significantly reduced by this method compared with the strategy involving intubation, surfactant administration and early extubation.

Effect of parenterally L-arginine supplementation on the respiratory distress syndrome in preterm newborns

L-Arginine (L-Arg) is the precursor of nitric oxide which plays an important role on pulmonary circulation and pulmonary vascular tone. Earlier studies suggested that L-Arg levels in preterm newborns with respiratory distress syndrome (RDS) were low due to its consumption and L-Arg supplementation may reduce the severity of RDS. Our aim was detect the effect of the parenterally L-Arg supplementation on RDS severity. The subjects were chosen between preterm newborns (gestational age <34 weeks) (n = 30). Twenty of the subjects were diagnosed with permaturity and RDS, and 10 of the subjects were healthy preterm newborns. Ten of the subjects was taken L-Arg (1.5 mmol/kg/d) in addition to routine RDS treatment and assumed as "Group 1". In this group, daily L-Arg supplementation was started end of the first day, and continued at end of fifth day. The others of the subjects diagnosed with RDS was take routine RDS treatment and assumed as "Group 2". Healthy preterm newborns assumed as "Group 3". Blood collections for L-Arg levels via tandem mass spectrometry were made in first day and repeated on the seventh days. Oxygenation index was used to determine severity of RDS. L-Arg consentrations in Group 1 were 8.7 ± 4.1 μM/L and 11.9 ± 5.0 μM/L in first and seventh day, respectively. L-Arg consentrations were 12.6 ± 4.5 μM/Land 10.9 ± 5.4 μM/L in Group 2 and 8.6 ± 5.1 μM/L and 9.4 ± 4.1 μM/L in Group 3. There is no correlation between L-Arg concentrations and OI also duration of the mechanical ventilation of the subjects in patient groups (Group 1 and 2).

Early administration of surfactant via a thin intratracheal catheter in preterm infants with respiratory distress syndrome: Feasibility and outcome

Objective:

Currently, the method of early nasal continuous positive airway pressure (nCPAP) and selective administration of surfactant via an endotracheal tube is widely used in the treatment of respiratory distress syndrome (RDS) in premature infants. To prevent complications related to endotracheal intubation and even a brief period of mechanical ventilation, in this study, we compared the effectiveness of surfactant administration via a thin intratracheal catheter versus the current method using an endotracheal tube.

Methods:

Thirty eight preterm infants ≤34 weeks' gestation with birth weight of 1000–1800 g who were putted on nCPAP for RDS within the first hour of life, were randomly assigned to receive surfactant either via endotracheal tube (ET group) or via thin intratracheal catheter (CATH group). The primary outcomes were the need for mechanical ventilation and duration of oxygen therapy. Data were analyzed by independent t-test, Mann-Whitney U-test, and Chi-square test, using SPSS v. 21.

Findings:

There was no significant difference between groups regarding to need for mechanical ventilation during the first 72 h of birth (3 [15.8%] in ET group vs. 2 [10.5%] in CATH group; P = 0.99). Duration of oxygen therapy in CATH group was significantly lower than ET group (243.7 ± 74.3 h vs. 476.8 ± 106.8 h, respectively; P = 0.018). The incidence of adverse events during all times of surfactant administration was not statistically significant between groups (P = 0.14), but the number of infants who experienced adverse events during surfactant administration was significantly lower in CATH group than ET group (6 [31.6%] vs. 12 [63.2%], respectively; P = 0.049). All other outcomes, including duration of treatment with CPAP and mechanical ventilation, times of surfactant administration and the need for more than one dose of the drug, the rate of intraventricular hemorrhage, mortality and combined outcome of chronic lung disease or mortality were statistically similar between the groups

Conclusion:

Surfactant administration via thin intratracheal catheter in preterm infants receiving nCPAP for treatment of RDS has similar efficacy, feasibility and safety to its administration via endotracheal tube.

Acute Neonatal Respiratory Failure

Acute respiratory failure requiring assisted ventilation is one of the most common reasons for admission to the neonatal intensive care unit. Respiratory failure is the inability to maintain either normal delivery of oxygen to the tissues or normal removal of carbon dioxide from the tissues. It occurs when there is an imbalance between the respiratory workload and ventilatory strength and endurance. Definitions are somewhat arbitrary but suggested laboratory criteria for respiratory failure include two or more of the following: PaCO₂ > 60 mmHg, PaO₂ < 50 mmHg or O₂ saturation <80 % with an FiO₂ of 1.0 and pH < 7.25 (Wen et al. 2004).

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.

The OPTIMIST-A trial: evaluation of minimally-invasive surfactant therapy in preterm infants 25-28 weeks gestation

Background

It is now recognized that preterm infants ≤28 weeks gestation can be effectively supported from the outset with nasal continuous positive airway pressure. However, this form of respiratory therapy may fail to adequately support those infants with significant surfactant deficiency, with the result that intubation and delayed surfactant therapy are then required. Infants following this path are known to have a higher risk of adverse outcomes, including death, bronchopulmonary dysplasia and other morbidities. In an effort to circumvent this problem, techniques of minimally-invasive surfactant therapy have been developed, in which exogenous surfactant is administered to a spontaneously breathing infant who can then remain on continuous positive airway pressure. A method of surfactant delivery using a semi-rigid surfactant instillation catheter briefly passed into the trachea (the “Hobart method”) has been shown to be feasible and potentially effective, and now requires evaluation in a randomised controlled trial.

Methods/design

This is a multicentre, randomised, masked, controlled trial in preterm infants 25–28 weeks gestation. Infants are eligible if managed on continuous positive airway pressure without prior intubation, and requiring FiO₂ ≥ 0.30 at an age ≤6 hours. Randomisation will be to receive exogenous surfactant (200 mg/kg poractant alfa) via the Hobart method, or sham treatment. Infants in both groups will thereafter remain on continuous positive airway pressure unless intubation criteria are reached (FiO₂ ≥ 0.45, unremitting apnoea or persistent acidosis). Primary outcome is the composite of death or physiological bronchopulmonary dysplasia, with secondary outcomes including incidence of death; major neonatal morbidities; durations of all modes of respiratory support and hospitalisation; safety of the Hobart method; and outcome at 2 years. A total of 606 infants will be enrolled. The trial will be conducted in >30 centres worldwide, and is expected to be completed by end-2017.

Discussion

Minimally-invasive surfactant therapy has the potential to ease the burden of respiratory morbidity in preterm infants. The trial will provide definitive evidence on the effectiveness of this approach in the care of preterm infants born at 25–28 weeks gestation.

Trial registration

Australia and New Zealand Clinical Trial Registry: ACTRN12611000916943; ClinicalTrials.gov: NCT02140580.

Adjunctive drug therapies for treatment of respiratory diseases in the newborn: based on evidence or habit?

Respiratory distress syndrome is a disease of prematurity and is caused by a relative deficiency of endogenous surfactant production. Respiratory distress syndrome is the most common cause of mortality and morbidity in the newborn population and the standard of care is to provide exogenous surfactant therapy. This saves lives and reduces respiratory complications but, despite treatment, a significant proportion of these infants go onto develop chronic lung disease, the severest form of which is bronchopulmonary dysplasia. Once developed, this is a multisystem disease and treatment is mostly supportive by using various therapeutic adjuncts. Some of these have been proven to be safe and effective in large randomized, controlled trials but similar evidence for other drugs is lacking. The aim of this paper is to provide an overview and critically appraise the available scientific evidence for or against their use in routine practice.

Less invasive surfactant administration (LISA) - ways to deliver surfactant in spontaneously breathing infants

The idea to deliver surfactant to spontaneously breathing premature infants is not new. The spectrum of methods reported reaches from aerosol administration over pharyngeal deposition, the use of laryngeal masks, short term intubation, surfactant administration and rapid extubation (INSURE) to an approach of keeping premature neonates on spontaneous breathing with continuous positive airway pressure support and administering surfactant by laryngoscopy via a small diameter tube. This way of Less Invasive Surfactant Administration (LISA) is in increasing use in the last decade in Germany. More than 1000 babies have been included in clinical studies on LISA by now. A first prospective randomized controlled trial (AMV-trial) demonstrated a significant reduction in the use of mechanical ventilation in LISA patients compared to standard treatment with intratracheal bolus administration of surfactant. Another recent study (Take Care study) indicates, that LISA may even be superior to INSURE. The search for even more "gentle" methods (e.g. nebulization) to deliver surfactant continues.

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.

Delivery and performance of surfactant replacement therapies to treat pulmonary disorders

Lung surfactant is crucial for optimal pulmonary function throughout life. An absence or deficiency of surfactant can affect the surfactant pool leading to respiratory distress. Even if the coupling between surfactant dysfunction and the underlying disease is not always well understood, using exogenous surfactants as replacement is usually a standard therapeutic option in respiratory distress. Exogenous surfactants have been extensively studied in animal models and clinical trials. The present article provides an update on the evolution of surfactant therapy, types of surfactant treatment, and development of newer-generation surfactants. The differences in the performance between various surfactants are highlighted and advanced research that has been conducted so far in developing the optimal delivery of surfactant is discussed.

Less invasive surfactant administration in extremely preterm infants: impact on mortality and morbidity

BACKGROUND

A new mode of surfactant administration without intubation - less invasive surfactant administration (LISA) - has recently been described for premature infants.

OBJECTIVE

We report single-center outcome data of extremely premature infants who have been managed by LISA in our department. Mortality and morbidity rates of the cohort were compared to historical controls from our own center and to data of the Vermont-Oxford Neonatal Network (VONN).

PATIENTS AND METHODS

All infants born at 23-27 weeks' gestational age during 01/2009 and 06/2011 (n = 224) were managed by LISA and included in the study group.

RESULTS

LISA was tolerated by 94% of all infants. 68% of infants stayed on continuous positive airway pressure on day 3. The rate of mechanical ventilation was 35% within the first week and 59% during the entire hospital stay. Compared to historical controls, we found significantly higher survival rates (75.8 vs. 64.1%) and significantly less intraventricular hemorrhage (IVH) (28.1 vs. 45.9%), severe IVH (13.1 vs. 23.9%) and cystic periventricular leukomalacia (1.2 vs. 5.6%); only persistent ductus arteriousus (PDA) (74.7 vs. 52.6%) and retinopathy of prematurity (ROP) (40.5 vs. 21.1%) occurred significantly more often. Compared to VONN data, we found significantly less chronic lung disease (20.6 vs. 46.4%), severe cerebral lesions (IVH 3/4 + cystic PVL; 9.4 vs. 16.1%) and ROP (all grades) (40.5 vs. 56.5%); only PDA (74.7 vs. 63.1%) and severe ROP (> grade 2) (24.1 vs. 14.1%) occurred significantly more often in our cohort.

CONCLUSION

Surfactant can be effectively and safely delivered via LISA and this is associated with low rates of mechanical ventilation and various adverse outcomes in extremely premature infants.

The journey towards lung protective respiratory support in preterm neonates

The aim of this conceptual review is to provide the reader with a broad perspective on progress made in respiratory support of preterm infants over the past five decades. Landmark discoveries are described in their historical context and underlying theories of lung protection are discussed. The review finishes by integrating different approaches and perspectives into a state-of-the-art concept for lung-protective ventilation in this fragile patient population. Improvements in neonatal respiratory support in the 1970s and 1980s have contributed to dramatic improvements of mortality and morbidity rates among neonates with respiratory failure. Continuous positive airway pressure, antenatal corticosteroids and surfactant replacement therapy revolutionized the care of preterm infants. With the recognition that atelectrauma, volutrauma and oxygen toxicity are the main factors contributing to ventilator-induced lung injury, lung-protective strategies, including noninvasive respiratory support, tidal volume targeting during conventional mechanical ventilation and high frequency ventilation were developed in the 1990s. Given the fact that progress made in the last decade has only resulted in minor improvements in mortality and morbidity rates of neonates with respiratory failure, it seems unlikely that further refinements of current technologies will produce giant leaps forward in high-resource countries. It appears that entirely new approaches would be required. In contrast, knowledge and technology transfer of basic respiratory support strategies (e.g. use of oxygen, simple systems to provide continuous positive airway pressure), could have an enormous impact on the prognosis of neonates with respiratory failure in low-resource countries.

Novel approaches to surfactant administration

Surfactant replacement therapy has been the mainstay of treatment for preterm infants with respiratory distress syndrome for more than twenty years. For the most part, surfactant is administered intratracheally, followed by mechanical ventilation. In recent years, the growing interest in noninvasive ventilation has led to novel approaches of administration. This paper will review these techniques and the associated clinical evidence.

Respiratory distress syndrome at birth is a risk factor for hospitalization for lower respiratory tract infections in infancy

BACKGROUND

Respiratory distress syndrome (RDS) and hospitalization for lower respiratory tract infection (LRTI; specifically, respiratory syncytial virus) are important causes of morbidity in infancy. Whether RDS at birth is an independent risk factor for LRTI is unknown. This study estimated the risk of LRTI-related hospitalization among late preterm infants with a history of RDS.

METHODS

The population-based cohort from Québec included all late preterm infants (32-36 weeks gestational age) born in 1996 to 1997. RDS was identified by International Classification of Diseases, Ninth Revision code 769, and a comparison cohort generated from all without RDS. A multivariable model estimated the adjusted odds ratio of LRTI-related hospitalization among late preterm infants with a history of RDS; and the incidence and increased risk of childhood chronic respiratory morbidity was calculated.

RESULTS

Of the 7488 late preterms, 459 (6.1%) had a history of RDS; 525 late preterms (7.0%) were hospitalized for LRTI in infancy, including 57 (12.4%) with RDS. The adjusted odds ratio for LRTI-related hospitalization associated with RDS was 1.6 (1.2-2.2). Other significant risk factors included male sex, or diagnosis of other respiratory conditions, diaphragm anomalies, bacteremia, intraventricular hemorrhage, congenital heart disease or respiratory system anomalies. Late preterm infants with a history of RDS were also at a significantly increased risk of childhood chronic respiratory morbidity.

CONCLUSIONS

Late preterms with a history of RDS are at a 60% increased risk of LRTI-related hospitalization in infancy compared with late preterm infants without RDS. Such infants may benefit from interventions decreasing the risk of contracting respiratory viruses causing acute LRTI.

Nebulised surfactant in preterm infants with or at risk of respiratory distress syndrome

BACKGROUND

Nebulised surfactant has the potential to deliver surfactant to the infant lung with the goal of avoiding endotracheal intubation and ventilation, ventilator-induced lung injury and bronchopulmonary dysplasia (BPD).

OBJECTIVES

To determine the effect of nebulised surfactant administration either as prophylaxis or treatment compared to placebo, no treatment or intratracheal surfactant administration on morbidity and mortality in preterm infants with, or at risk of, respiratory distress syndrome (RDS).

SEARCH METHODS

Searches were performed of CENTRAL (The Cochrane Library, January 2012), MEDLINE and PREMEDLINE (1950 to January 2012), EMBASE (1980 to January 2012) and CINAHL (1982 to January 2012), as well as proceedings of scientific meetings, clinical trial registries, Google Scholar and reference lists of identified studies. Expert informants and surfactant manufacturers were contacted.

SELECTION CRITERIA

Randomised, cluster-randomised or quasi-randomised controlled trials of nebulised surfactant administration compared to placebo, no treatment, or other routes of administration (laryngeal, pharyngeal instillation of surfactant before the first breath, thin endotracheal catheter surfactant administration or intratracheal surfactant instillation) on morbidity and mortality in preterm infants at risk of RDS. We considered published, unpublished and ongoing trials.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for eligibility and quality, and extracted data.

MAIN RESULTS

No studies of prophylactic or early nebulised surfactant administration were found. A single small study of late rescue nebulised surfactant was included. The study is of moderate risk of bias. The study enrolled 32 preterm infants born < 36 weeks' gestation with RDS on nasal continuous positive airway pressure (nCPAP). The study reported no significant difference between nebulised surfactant administration compared to no treatment groups in chronic lung disease (risk ratio (RR) 5.00; 95% confidence interval (CI) 0.26 to 96.59) or other outcomes (oxygenation 1 to 12 hours after randomisation, need for mechanical ventilation, days of mechanical ventilation or continuous positive airways pressure (CPAP) or days of supplemental oxygen). No side effects of the nebulised surfactant therapy or aerosol inhalation were reported.

AUTHORS' CONCLUSIONS

There are insufficient data to support or refute the use of nebulised surfactant in clinical practice. Adequately powered trials are required to determine the effect of nebulised surfactant administration for prevention or early treatment of RDS in preterm infants. Nebulised surfactant administration should be limited to clinical trials.

Initial respiratory support of preterm infants: the role of CPAP, the INSURE method, and noninvasive ventilation

This article explores the potential benefits and risks for the various approaches to the initial respiratory management of preterm infants. The authors focus on the evidence for the increasingly used strategies of initial respiratory support of preterm infants with continuous positive airway pressure (CPAP) beginning in the delivery room or very early in the hospital course and blended strategies involving the early administration of surfactant replacement followed by immediate extubation and stabilization on CPAP. Where possible, the evidence referenced in this review comes from individual randomized controlled trials or meta-analyses of those trials.

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.