Aerosolized Calfactant for Newborns With Respiratory Distress: A Randomized Trial

Respiratory Severity Score during the First 3 Hours of Life as a Predictor for Failure of Noninvasive Respiratory Support and Need for Late Rescue Surfactant Administration

OBJECTIVE

 Preterm infants often develop failure of noninvasive respiratory support. These infants miss the advantages of early rescue surfactant therapy. In this study, we evaluate the utility of respiratory severity score (RSS) during the first 3 hours of life (HOL) as a predictor for failure of noninvasive respiratory support.

STUDY DESIGN

 We conducted a post hoc analysis of infants between 23 and 40 weeks' gestational age who received usual care in the AERO-02 clinical trial. Univariate and multivariable logistic regression analysis were used to assess whether the RSS summary measures were associated with the odds of surfactant administration.

RESULTS

 Study involved 146 infants. Sixty-four infants (45%) received surfactant within the first 72 hours. Administration of surfactant was associated with the mean RSS (p < 0.01) and the linear trend (p < 0.01).

CONCLUSION

 We demonstrated that RSS during the first 3 HOL can predict failure of noninvasive respiratory support and need for late rescue surfactant administration. Optimal RSS cutoffs for early rescue surfactant therapy need to be determined in large cohort studies.

KEY POINTS

· Early recognition of infants at risk of failure of noninvasive ventilation is important to prevent complications.. · It is desirable to identify patients who would benefit from early rescue surfactant treatment.. · RSS in first 3 hours can be used as a predictor of failure of noninvasive respiratory support..

High vs low CPAP strategy with aerosolized calfactant in preterm infants with respiratory distress syndrome

BACKGROUND

Optimal CPAP strategy to prevent CPAP failure defined as need for endotracheal intubation is unknown.

OBJECTIVE

To evaluate the risk of CPAP failure in infants treated with high vs low CPAP strategy while receiving aerosolized calfactant in the AERO-02 clinical trial and AERO-03 expanded access program.

METHODS

Infants born between 29 0/7 to 36 6/7 weeks were included. Comparisons were made between low and high CPAP groups (Low, 4-7 cm H2O; High, 8-10 cm H2O).

RESULTS

CPAP failure and pneumothorax were not different between the groups. Odds of CPAP failure were not different after adjustment for baseline characteristics (OR = 0.61; 95% CI: 0.29, 1.24).

CONCLUSION

We found no difference in CPAP failure among infants who received aerosolized calfactant that were treated with high vs low CPAP strategy. Efficacy of high CPAP strategy with aerosolized surfactant treatment needs to be evaluated in future studies.

Less invasive surfactant administration methods: Who, what and how

Surfactant administration via an endotracheal tube (ETT) has been the standard of care for infants with respiratory distress syndrome for decades. As non-invasive ventilation has become commonplace in the NICU, methods for administering surfactant without use of an ETT have been developed. These methods include thin catheter techniques (LISA, MIST), aerosolization/ nebulization, and surfactant administration through laryngeal (LMA) or supraglottic airways (SALSA). This review will describe these methods and discuss considerations and implementation into clinical practice.

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.

Less Invasive Surfactant Administration: A Viewpoint

The standard of care in treating respiratory distress syndrome in preterm infants is respiratory support with nasal continuous positive airway pressure or a combination of continuous positive airway pressure and exogenous surfactant replacement. Endotracheal intubation, the conventional method for surfactant administration, is an invasive procedure associated with procedural and mechanical ventilation complications. The INSURE (intubation, surfactant administration, and extubation soon after) technique is an accepted method aimed at reducing the short-term complications and long-term morbidities related to mechanical ventilation but does not eliminate risks associated with endotracheal intubation and mechanical ventilation. Alternative methods of surfactant delivery that can overcome the problems associated with the INSURE technique are surfactant through a laryngeal mask, surfactant through a thin intratracheal catheter, and aerosolized surfactant delivered using nebulizers. The three alternative methods of surfactant delivery studied in the last two decades have advantages and limitations. More than a dozen randomized controlled trials have aimed to study the benefits of the three alternative techniques of surfactant delivery compared with INSURE as the control arm, with promising results in terms of reduction in mortality, need for mechanical ventilation, and bronchopulmonary dysplasia. The need to find a less invasive surfactant administration technique is a clinically relevant problem. Before broader adoption in routine clinical practice, the most beneficial technique among the three alternative strategies should be identified. This review aims to summarize the current evidence for using the three alternative techniques of surfactant administration in neonates, compare the three techniques, highlight the knowledge gaps, and suggest future directions. KEY POINTS: · The need to find a less invasive alternative method of surfactant delivery is a clinically relevant problem.. · Clinical trials that have studied alternative surfactant delivery methods have shown promising results but are inconclusive for broader adoption into clinical practice.. · Future studies should explore novel clinical trial methodologies and select clinically significant long term outcomes for comparison..

Pulmonary Surfactant: A Mighty Thin Film

Pulmonary surfactant is a critical component of lung function in healthy individuals. It functions in part by lowering surface tension in the alveoli, thereby allowing for breathing with minimal effort. The prevailing thinking is that low surface tension is attained by a compression-driven squeeze-out of unsaturated phospholipids during exhalation, forming a film enriched in saturated phospholipids that achieves surface tensions close to zero. A thorough review of past and recent literature suggests that the compression-driven squeeze-out mechanism may be erroneous. Here, we posit that a surfactant film enriched in saturated lipids is formed shortly after birth by an adsorption-driven sorting process and that its composition does not change during normal breathing. We provide biophysical evidence for the rapid formation of an enriched film at high surfactant concentrations, facilitated by adsorption structures containing hydrophobic surfactant proteins. We examine biophysical evidence for and against the compression-driven squeeze-out mechanism and propose a new model for surfactant function. The proposed model is tested against existing physiological and pathophysiological evidence in neonatal and adult lungs, leading to ideas for biophysical research, that should be addressed to establish the physiological relevance of this new perspective on the function of the mighty thin film that surfactant provides.

Surfactant delivery by aerosol inhalation - past, present, and future

Surfactant replacement therapy (SRT) by nebulization to spontaneously breathing patients has been regarded as the Holy Grail since surfactant deficiency was first identified as the cause for neonatal respiratory distress syndrome. It avoids neonatal endotracheal intubation, a procedure that is often difficult and occasionally harmful. Unapproved alternatives to endotracheal tube placement for liquid surfactant instillation, such as LISA (thin catheter intubation) and SALSA (supraglottic airway insertion) have significant merit but are still invasive, leaving nebulized SRT as the only truly non-invasive method. In the past 60 years, we have learned much about the potential - and limitations - of nebulized SRT. In this review, we examine the promises and pitfalls of nebulized SRT, discuss what we know about neonatal aerosol drug delivery and recap some of the most recent randomized clinical trials of nebulized SRT. We conclude with a discussion of what is known and the next steps needed if this type of SRT is to become a regular part of clinical care.

Race and Ethnicity of Infants Enrolled in Neonatal Clinical Trials: A Systematic Review

Importance

Representativeness of populations within neonatal clinical trials is crucial to moving the field forward. Although racial and ethnic disparities in research inclusion are well documented in other fields, they are poorly described within neonatology.

Objective

To describe the race and ethnicity of infants included in a sample of recent US neonatal clinical trials and the variability in this reporting.

Evidence Review

A systematic search of US neonatal clinical trials entered into Cochrane CENTRAL 2017 to 2021 was conducted. Two individuals performed inclusion determination, data extraction, and quality assessment independently with discrepancies adjudicated by consensus.

Findings

Of 120 studies with 14 479 participants that met the inclusion criteria, 75 (62.5%) included any participant race or ethnicity data. In the studies that reported race and ethnicity, the median (IQR) percentage of participants of each background were 0% (0%-1%) Asian, 26% (9%-42%) Black, 3% (0%-12%) Hispanic, 0% (0%-0%) Indigenous (eg, Alaska Native, American Indian, and Native Hawaiian), 0% (0%-0%) multiple races, 57% (30%-68%) White, and 7% (1%-21%) other race or ethnicity. Asian, Black, Hispanic, and Indigenous participants were underrepresented, while White participants were overrepresented compared with a reference sample of the US clinical neonatal intensive care unit (NICU) population from the Vermont Oxford Network. Many participants were labeled as other race or ethnicity without adequate description. There was substantial variability in terms and methods of reporting race and ethnicity data. Geographic representation was heavily skewed toward the Northeast, with nearly one-quarter of states unrepresented.

Conclusions and Relevance

These findings suggest that neonatal research may perpetuate inequities by underrepresenting Asian, Black, Hispanic, and Indigenous neonates in clinical trials. Studies varied in documentation of race and ethnicity, and there was regional variation in the sites included. Based on these findings, funders and clinical trialists are advised to consider a 3-point targeted approach to address these issues: prioritize identifying ways to increase diversity in neonatal clinical trial participation, agree on a standardized method to report race and ethnicity among neonatal clinical trial participants, and prioritize the inclusion of participants from all regions of the US in neonatal clinical trials.

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.

A multicentre neonatal interventional randomised controlled trial of nebulized surfactant for preterm infants with respiratory distress: Neo-INSPIRe trial protocol

INTRODUCTION

Respiratory distress syndrome in preterm infants is an important cause of morbidity and mortality. Less invasive methods of surfactant administration, along with the use of continuous positive airway pressure (CPAP), have improved outcomes of preterm infants. Aerosolized surfactant can be given without the need for airway instrumentation and may be employed in areas where these skills are scarce. Recent trials from high-resourced countries utilising aerosolized surfactant have had a low quality of evidence and varying outcomes.

METHODS AND ANALYSIS

The Neo-INSPIRe trial is an unblinded, multicentre, randomised trial of a novel aerosolized surfactant drug/device combination. Inclusion criteria include preterm infants of 27-34+6 weeks' gestational age who weigh 900-1999g and who require CPAP with a fraction of inspired oxygen (FiO2) of 0.25-0.35 in the first 2-24 h of age. Infants are randomised 1:1 to control (CPAP alone) or intervention (CPAP with aerosolized surfactant). The primary outcome is the need for intratracheal bolus surfactant instillation within 72 h of age. Secondary outcomes include the incidence of reaching failure criteria (persistent FiO2 of > 0.40, severe apnoea or severe work of breathing), the need for and duration of ventilation and respiratory support, bronchopulmonary dysplasia and selected co-morbidities of prematurity. Assuming a 40% relative risk reduction to reduce the proportion of infants requiring intratracheal bolus surfactant from 45 to 27%, the study will aim to enrol 232 infants for the study to have a power of 80% to detect a significant difference with a type 1 error of 0.05.

ETHICS AND DISSEMINATION

Ethical approval has been granted by the relevant human research ethics committees at University of Cape Town (HREC 681/2022), University of the Witwatersrand HREC (221112) and Stellenbosch University (M23/02/004).

TRIAL REGISTRATION

PACTR202307490670785.

Response to aerosolized calfactant in infants with respiratory distress syndrome; a post-hoc analysis of AERO-02 trial

BACKGROUND

The aerosolized calfactant decreased the need for intubation in neonates with respiratory distress syndrome (AERO-02 trial).

OBJECTIVE

To determine the oxygenation response to aerosolized calfactant among infants born 28 0/7-36 6/7 weeks with RDS in the AERO-02 trial.

METHODS

Trends in hourly fraction of oxygen (FiO2), mean airway pressure (MAP) and respiratory severity score (RSS) were compared between the aerosolized calfactant (AC) and usual care (UC) groups from time of randomization for 72 h.

RESULTS

A total of 353 subjects were included in the study. FiO2, MAP, and RSS were lower in the UC group. FiO2 decrease was seen after the first aerosolized calfactant dose.

CONCLUSION

FiO2, MAP, and RSS were lower in the UC group. This is likely due to early and higher rate of liquid surfactant administration in the UC group. Decrease in FiO2 was noted in the AC group after the first aerosolization.

RDS-NExT workshop: consensus statements for the use of surfactant in preterm neonates with RDS

OBJECTIVE

To provide the best clinical practice guidance for surfactant use in preterm neonates with respiratory distress syndrome (RDS). The RDS-Neonatal Expert Taskforce (RDS-NExT) initiative was intended to add to existing evidence and clinical guidelines, where evidence is lacking, with input from an expert panel.

STUDY DESIGN

An expert panel of healthcare providers specializing in neonatal intensive care was convened and administered a survey questionnaire, followed by 3 virtual workshops. A modified Delphi method was used to obtain consensus around topics in surfactant use in neonatal RDS.

RESULT

Statements focused on establishing RDS diagnosis and indicators for surfactant administration, surfactant administration methods and techniques, and other considerations. After discussion and voting, consensus was achieved on 20 statements.

CONCLUSION

These consensus statements provide practical guidance for surfactant administration in preterm neonates with RDS, with a goal to contribute to improving the care of neonates and providing a stimulus for further investigation to bridge existing knowledge gaps.

Predictors of successful treatment of respiratory distress with aerosolized calfactant

INTRODUCTION

Predictors for successful aerosolized surfactant treatment are not well defined.

OBJECTIVE

To identify predictors for successful treatment in the AERO-02 trial and the AERO-03 expanded access program.

METHODS

Neonates receiving nasal continuous positive airway pressure (NCPAP) at the time of first aerosolized calfactant administration were included in this analysis. Associations between demographic and clinical predictors to need for intubation were examined using univariate testing and multivariate logistic regression analyses.

RESULTS

Three hundred and eighty infants were included in the study. Overall, 24% required rescue by intubation. Multivariate modeling revealed that the predictors of successful treatment were a gestational age ≥31 weeks, a respiratory severity score (RSS) of <1.9, and <2 previous aerosol treatments.

CONCLUSION

Gestational age, number of aerosols, and RSS are predictive of successful treatment. These criteria will help select patients most likely to benefit from aerosolized surfactant.

Randomized Trial of Surfactant Therapy via Laryngeal Mask Airway Versus Brief Tracheal Intubation in Neonates Born Preterm

OBJECTIVE

To evaluate the possible noninferiority of surfactant administration via laryngeal mask airway (LMA) vs endotracheal tube (ETT) in avoiding the requirement for mechanical ventilation in preterm neonates with respiratory distress syndrome (RDS).

STUDY DESIGN

This was a randomized controlled trial including infants born at 27 to 36 weeks of gestation, >800 g, diagnosed with RDS and receiving fraction of inspired oxygen 0.30-0.60 via noninvasive respiratory support. Infants were randomized to surfactant via LMA (with atropine premedication) or ETT (InSuRE approach with atropine and remifentanil premedication). Primary outcome was failure of surfactant treatment to prevent the need for mechanical ventilation.

RESULTS

Patients were randomized, 51 to LMA and 42 to the ETT group. Both groups had similar baseline characteristics, with birth weights ranging from 810 to 3560 g. Failure rate was 29% in the ETT group and 20% in the LMA group (P = .311). This difference was due to early failures (within 1 hour), with 12.5% in the ETT group and 2% in the LMA group (P = .044). Surfactant therapy via LMA was non-inferior to administration via ETT; failure risk difference -9.0% (CI -∞ to 5.7%). Efficacy in decreasing fraction of inspired oxygen, number of surfactant doses administered, time to wean off all respiratory support, rates of adverse events, and outcomes including pneumothorax and BPD diagnosis did not differ between groups.

CONCLUSIONS

Surfactant therapy via LMA was noninferior to administration via ETT and it decreased early failures, possibly by avoiding adverse effects of premedication, laryngoscopy, and intubation. These characteristics make LMA a desirable conduit for surfactant administration.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02164734.

Changing epidemiology of congenital heart disease: effect on outcomes and quality of care in adults

The epidemiology of congenital heart disease (CHD) has changed in the past 50 years as a result of an increase in the prevalence and survival rate of CHD. In particular, mortality in patients with CHD has changed dramatically since the latter half of the twentieth century as a result of more timely diagnosis and the development of interventions for CHD that have prolonged life. As patients with CHD age, the disease burden shifts away from the heart and towards acquired cardiovascular and systemic complications. The societal costs of CHD are high, not just in terms of health-care utilization but also with regards to quality of life. Lifespan disease trajectories for populations with a high disease burden that is measured over prolonged time periods are becoming increasingly important to define long-term outcomes that can be improved. Quality improvement initiatives, including advanced physician training for adult CHD in the past 10 years, have begun to improve disease outcomes. As we seek to transform lifespan into healthspan, research efforts need to incorporate big data to allow high-value, patient-centred and artificial intelligence-enabled delivery of care. Such efforts will facilitate improved access to health care in remote areas and inform the horizontal integration of services needed to manage CHD for the prolonged duration of survival among adult patients.

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.

Prophylactic surfactant nebulisation for the early aeration of the preterm lung: a randomised clinical trial

OBJECTIVE

The effect of prophylactic surfactant nebulisation (SN) is unclear. We aimed to determine whether prophylactic SN improves early lung aeration.

DESIGN

Parallel, randomised clinical trial, conducted between March 2021 and January 2022.

SETTING

Delivery room (DR) of a tertiary neonatal centre in Zurich, Switzerland.

PATIENTS

Preterm infants between 26 ^0/7 and 31 ^6/7 weeks gestation INTERVENTIONS: Infants were randomised to receive positive distending pressure alone or positive distending pressure and additional SN (200 mg/kg; poractant alfa) using a customised vibrating membrane nebuliser. SN commenced with the first application of a face mask immediately after birth.

MAIN OUTCOME MEASURES

Primary outcome was the difference in end-expiratory lung impedance from birth to 30 min after birth (∆EELI_30min). EELI correlates well with functional residual capacity. Secondary outcomes included physiological and clinical outcomes.

RESULTS

Data from 35 infants were collected, and primary outcome data were analysed from 32 infants (n=16/group). Primary outcome was not different between intervention and control group (median (IQR): 25 (7-62) vs 10 (0-26) AU/kg, p=0.21). ∆EELI was slightly higher in the intervention group at 6 and 12 hours after birth, particularly in the central areas of the lung. There were no differences in cardiorespiratory and clinical parameters. Two adverse events were noted in the intervention group.

CONCLUSIONS

Prophylactic SN in the DR did not significantly affect ∆EELI_30min and showed only minimal effects on lung physiology. Prophylactic SN in the DR was feasible. There were no differences in clinical outcomes.

TRIAL REGISTRATION NUMBER

NCT04315636.

Effects of cholesterol on the structure and collapse of DPPC monolayers

Cholesterol induces faster collapse by compressed films of pulmonary surfactant. Because collapse prevents films from reaching the high surface pressures achieved in the alveolus, most therapeutic surfactants remove or omit cholesterol. The studies here determined the structural changes by which cholesterol causes faster collapse by films of dipalmitoyl phosphatidylcholine, used as a simple model for the functional alveolar film. Measurements of isobaric collapse, with surface pressure held constant at 52 mN/m, showed that cholesterol had little effect until the mol fraction of cholesterol, Xchol, exceeded 0.20. Structural measurements of grazing incidence X-ray diffraction at ambient laboratory temperatures and a surface pressure of 44 mN/m, just below the onset of collapse, showed that the major structural change in an ordered phase occurred at lower Xchol. A centered rectangular unit cell with tilted chains converted to an untilted hexagonal structure over the range of Xchol = 0.0-0.1. For Xchol = 0.1-0.4, the ordered structure was nearly invariant; the hexagonal unit cell persisted, and the spacing of the chains was essentially unchanged. That invariance strongly suggests that above Xchol = 0.1, cholesterol partitions into a disordered phase, which coexists with the ordered domains. The phase rule requires that for a binary film with coexisting phases, the stoichiometries of the ordered and disordered regions must remain constant. Added cholesterol must increase the area of the disordered phase at the expense of the ordered regions. X-ray scattering from dipalmitoyl phosphatidylcholine/cholesterol fit with that prediction. The data also show a progressive decrease in the size of crystalline domains. Our results suggest that cholesterol promotes adsorption not by altering the unit cell of the ordered phase but by decreasing both its total area and the size of individual crystallites.

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.

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.

Providers' Attitudes to Proposed Changes in the Critical Congenital Heart Disease Screening Algorithm

Screening for critical congenital heart disease (CCHD) in newborns based on a 2009 Swedish study has become the standard of care despite the complexity of the algorithm. A simplified algorithm which might increase the false-positive rate was proposed in 2020 but not formally endorsed by the American Academy of Pediatrics. We sought to determine how the current protocol and the proposed changes are perceived by clinicians. We performed an anonymous survey of professionals involved in the care of newborns regarding their perception of the current and proposed CCHD screening algorithms. 335 responses were evaluated. Less than 2% of respondents were dissatisfied with the existing screening algorithm or felt it was difficult to perform. 47% endorsed and 12% opposed the adoption of the proposed modifications with those most familiar with the proposed changes more likely to endorse them. Although many providers would accept a higher false-positive rate in CCHD screening, those who would have to transfer a baby from the birth site for assessment after a failed CCHD screening were less tolerant of an increased false-positive rate. Although the existing CCHD screening mechanisms appear to be very well received, the proposed changes to the CCHD algorithm were viewed positively by many respondents. Changes in this algorithm would likely be better tolerated in those setting where the consequences of a failed CCHD screening are more easily addressed.

A Randomized, Controlled Trial to Investigate the Efficacy of Nebulized Poractant Alfa in Premature Babies with Respiratory Distress Syndrome

OBJECTIVE

To investigate the efficacy and safety of nebulized poractant alfa (at 200 and 400 mg/kg doses) delivered in combination with nasal continuous positive airway pressure compared with nasal continuous positive airway pressure alone in premature infants with diagnosed respiratory distress syndrome.

STUDY DESIGN

This randomized, controlled, multinational study was conducted in infants at 28^0/7 to 32^6/7 weeks of gestation. The primary outcome was the incidence of respiratory failure in the first 72 hours of life, defined as needing endotracheal surfactant and/or mechanical ventilation owing to prespecified criteria. Secondary outcomes included the time to respiratory failure in the first 72 hours, duration of ventilation, mortality, incidence of bronchopulmonary dysplasia, and major associated neonatal comorbidities. In addition, the safety and tolerability of the treatments were assessed reporting the number and percentage of infants with treatment-emergent adverse events and adverse drug reactions during nebulization.

RESULTS

In total, 129 infants were randomized. No significant differences were observed for the primary outcome: 24 (57%), 20 (49%), and 25 (58%) infants received endotracheal surfactant and/or mechanical ventilation within 72 hours in the poractant alfa 200 mg/kg, poractant alfa 400 mg/kg, and nasal continuous positive airway pressure groups, respectively. Similarly, secondary respiratory outcomes did not differ among groups. Enrollment was halted early owing to a change in the benefit-risk balance of the intervention. Nebulized poractant alfa was well-tolerated and safe, and no serious adverse events were related to the study treatment.

CONCLUSIONS

The intervention did not decrease the likelihood of respiratory failure within the first 72 hours of life.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03235986.

Aerosol Delivery of Lung Surfactant and Nasal CPAP in the Treatment of Neonatal Respiratory Distress Syndrome

After shifting away from invasive mechanical ventilation and intratracheal instillation of surfactant toward non-invasive ventilation with nasal CPAP and less invasive surfactant administration in order to prevent bronchopulmonary dysplasia in preterm infants with respiratory distress syndrome, fully non-invasive surfactant nebulization is the next Holy Grail in neonatology. Here we review the characteristics of animal-derived (clinical) and new advanced synthetic lung surfactants and improvements in nebulization technology required to secure optimal lung deposition and effectivity of non-invasive lung surfactant administration. Studies in surfactant-deficient animals and preterm infants have demonstrated the safety and potential of non-invasive surfactant administration, but also provide new directions for the development of synthetic lung surfactant destined for aerosol delivery, implementation of breath-actuated nebulization and optimization of nasal CPAP, nebulizer circuit and nasal interface. Surfactant nebulization may offer a truly non-invasive option for surfactant delivery to preterm infants in the near future.

Preclinical Assessment of Nebulized Surfactant Delivered through Neonatal High Flow Nasal Cannula Respiratory Support

High-flow nasal cannula (HFNC) is a non-invasive respiratory support (NRS) modality to treat premature infants with respiratory distress syndrome (RDS). The delivery of nebulized surfactant during NRS would represent a truly non-invasive method of surfactant administration and could reduce NRS failure rates. However, the delivery efficiency of nebulized surfactant during HFNC has not been evaluated in vitro or in animal models of respiratory distress. We, therefore, performed first a benchmark study to compare the surfactant lung dose delivered by commercially available neonatal nasal cannulas (NCs) and HFNC circuits commonly used in neonatal intensive care units. Then, the pulmonary effect of nebulized surfactant delivered via HFNC was investigated in spontaneously breathing rabbits with induced respiratory distress. The benchmark study revealed the surfactant lung dose to be relatively low for both types of NCs tested (Westmed NCs 0.5 ± 0.45%; Fisher & Paykel NCs 1.8 ± 1.9% of a nominal dose of 200 mg/kg of Poractant alfa). The modest lung doses achieved in the benchmark study are compatible with the lack of the effect of nebulized surfactant in vivo (400 mg/kg), where arterial oxygenation and lung mechanics did not improve and were significantly worse than the intratracheal instillation of surfactant. The results from the present study indicate a relatively low lung surfactant dose and negligible effect on pulmonary function in terms of arterial oxygenation and lung mechanics. This negligible effect can, for the greater part, be explained by the high impaction of aerosol particles in the ventilation circuit and upper airways due to the high air flows used during HFNC.

Efficacy, dose-response, and aerosol delivery of dry powder synthetic lung surfactant treatment in surfactant-deficient rabbits and premature lambs

BACKGROUND

Dry powder (DP) synthetic lung surfactant may be an effective means of noninvasive delivery of surfactant therapy to premature infants supported with nasal continuous positive airway pressure (nCPAP) in low-resource settings.

METHODS

Four experimental DP surfactant formulations consisting of 70% of phospholipids (DPPC:POPG 7:3), 3% Super Mini-B (SMB) or its sulfur-free derivate B-YL as SP-B peptide mimic, 25% of lactose or trehalose as excipient, and 2% of NaCl were formulated using spray drying. In vitro surface activity was confirmed with captive bubble surfactometry. Surfactant particle size was determined with a cascade impactor and inhaled dose was quantified using a spontaneously breathing premature lamb lung model supported with CPAP. In vivo surfactant efficacy was demonstrated in three studies. First, oxygenation and lung compliance were monitored after intratracheal instillation of resuspended DP surfactant in intubated, ventilated, lavaged, surfactant-deficient juvenile rabbits. In dose-response studies, ventilated, lavaged, surfactant-deficient rabbits received 30, 60, 120 or 240 mg/kg of DP B-YL:Lactose or B-YL:Trehalose surfactant by aerosol delivery with a low flow aerosol chamber via their endotracheal tube. Noninvasive aerosolization of DP B-YL:Trehalose surfactant via nasal prongs was tested in spontaneous breathing premature lambs supported with nCPAP. Intratracheal administration of 200 mg/kg of Curosurf®, a liquid porcine surfactant, was used as a positive control.

RESULTS

Mass median aerosol diameter was 3.6 μm with a geometric standard deviation of 1.8. All four experimental surfactants demonstrated high surface efficacy of intratracheal instillation of a bolus of ~ 100 mg/kg of surfactant with improvement of oxygenation and lung compliance. In the dose-response studies, rabbits received incremental doses of DP B-YL:Lactose or B-YL:Trehalose surfactant intratracheally and showed an optimal response in oxygenation and lung function at a dose of 120-240 mg/kg. Aerosol delivery via nasal prongs of 1 or 2 doses of ~ 100 mg/kg of B-YL:Trehalose surfactant to premature lambs supported with nCPAP resulted in stabilization of spontaneous breathing and oxygenation and lung volumes comparable to the positive control.

CONCLUSION

These studies confirm the clinical potential of DP synthetic lung surfactant with B-YL peptide as a SP-B mimic to alleviate surfactant deficiency when delivered as a liquid bolus or as an aerosol.

Novel Ventilation Strategies to Reduce Adverse Pulmonary Outcomes

Extremely preterm infants who must suddenly support their own gas exchange with lungs that are incompletely developed and lacking adequate amount of surfactant and antioxidant defenses are susceptible to lung injury. The decades-long quest to prevent bronchopulmonary dysplasia has had limited success, in part because of increasing survival of more immature infants. The process must begin in the delivery room with gentle assistance in establishing and maintaining adequate lung aeration, followed by noninvasive support and less invasive surfactant administration. Various modalities of invasive and noninvasive support have been used with varying degree of effect and are reviewed in this article.

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.

Trial of aerosolised surfactant for preterm infants with respiratory distress syndrome

OBJECTIVE

To evaluate the safety of an aerosolised surfactant, SF-RI 1, administered via nasal continuous positive airway pressure (nCPAP) and a prototype breath synchronisation device (AeroFact), to preterm infants with respiratory distress syndrome (RDS).

DESIGN

Multicentre, open-label, dose-escalation study with historical controls.

SETTING

Newborn intensive care units at Mater Mothers' Hospital, Brisbane, and Royal Hospital for Women, Sydney, Australia.

PATIENTS

Infants 26 weeks through 30 weeks gestation who required nCPAP 6-8 cmH₂O and fraction of inspired oxygen (FiO₂) <0.30 at <2 hours of age.

INTERVENTIONS

In part 1, infants received a single dose of 216 mg/kg of aerosolised surfactant. In part 2, infants could receive up to four doses of aerosolised surfactant. Three historical control infants were matched for each enrolled infant.

MAIN OUTCOME MEASURES

Treatment failure was defined as Respiratory Severity Score (FiO₂×cmH₂O nCPAP) >2.4, nCPAP >8 cmH₂O, arterial carbon dioxide >65 mm Hg, pH <7.20 or three severe apnoeas within 6 hours during the first 72 hours of life. Other outcomes included tolerance of the AeroFact treatment and complications of prematurity.

RESULTS

10 infants were enrolled in part 1 and 21 in part 2 and were compared with 93 historical controls. No safety issues were identified. In part 2, 6 of 21 (29%) AeroFact-treated infants compared with 30 of 63 (48%) control infants met failure criteria. Kaplan-Meier analysis of patients in part 2 showed a trend towards decreased rate of study failure in the AeroFact-treated infants compared with historical controls (p=0.10).

CONCLUSION

The AeroFact system can safely deliver aerosolised surfactant to preterm infants with RDS who are on nCPAP.

TRIAL REGISTRATION NUMBER

ACTRN12617001458325.

Surfactant Administration Through Laryngeal or Supraglottic Airways (SALSA): A Viable Method for Low-Income and Middle-Income Countries

Administration of liquid surfactant through an endotracheal tube for the treatment of respiratory distress syndrome has been the standard of care for decades. A skilled health care provider is needed to perform this procedure. In lower-income and middle-income countries (LMICs), healthcare resources are often limited, leading to increased mortality of premature infants, many of whom would benefit from surfactant administration. Therefore, having a simplified procedure for delivery of surfactant without the need for advanced skills could be life-saving, potentially diminish gaps in care, and help ensure more equitable global neonatal survival rates. Modifications to the standard approach of surfactant administration have been put into practice and these include: INtubation-SURfactant-Extubation (INSURE), thin catheter surfactant administration (TCA), aerosolized surfactant, and surfactant administration through laryngeal or supraglottic airways (SALSA). Although there is a need for larger studies to evaluate the comparative effectiveness of these newer methods, these methods are being embraced by the global community and being implemented in various settings throughout the world. Because the SALSA technique does not require laryngoscopy, a provider skilled in laryngoscopy is not required for the procedure. Therefore, because of the ease of use and safety profile, the SALSA technique should be strongly considered as a viable method of delivering surfactant in LMICs.

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.

Lung Deposition of Surfactant Delivered via a Dedicated Laryngeal Mask Airway in Piglets

It is unknown if the lung deposition of surfactant administered via a catheter placed through a laryngeal mask airway (LMA) is equivalent to that obtained by bolus instillation through an endotracheal tube. We compare the lung deposition of surfactant delivered via two types of LMA with the standard technique of endotracheal instillation. 25 newborn piglets on continuous positive airway pressure support (CPAP) were randomized into three groups: 1—LMA-camera (integrated camera and catheter channel; catheter tip below vocal cords), 2—LMA-standard (no camera, no channel; catheter tip above the glottis), 3—InSurE (Intubation, Surfactant administration, Extubation; catheter tip below end of endotracheal tube). All animals received 100 mg·kg⁻¹ of poractant alfa mixed with ^99mTechnetium-nanocolloid. Surfactant deposition was measured by gamma scintigraphy as a percentage of the administered dose. The median (range) total lung surfactant deposition was 68% (10–85), 41% (5–88), and 88% (67–92) in LMA-camera, LMA-standard, and InSurE, respectively, which was higher (p < 0.05) in the latter. The deposition in the stomach and nasopharynx was higher with the LMA-standard. The surfactant deposition via an LMA was lower than that obtained with InSurE. Although not statistically significant, introducing the catheter below the vocal cords under visual control with an integrated camera improved surfactant LMA delivery by 65%.

Surfactant Nebulization to Prevent Intubation in Preterm Infants: A Systematic Review and Meta-analysis

CONTEXT

Surfactant nebulization (SN) may offer a safe alternative for surfactant administration in respiratory distress syndrome of preterm infants.

OBJECTIVE

To evaluate the efficacy of SN for the prevention of early intubation.

DATA SOURCES

Medline, Embase, The Cochrane Library, clinicaltrials.gov, published abstracts, and references of relevant articles were searched through March 23, 2021.

STUDY SELECTION

Randomized clinical trials of preterm infants <37 weeks' gestation comparing SN with noninvasive respiratory support or intratracheal surfactant application.

DATA EXTRACTION

Two reviewers extracted data and assessed risk of bias from included studies separately and blinded. Data were pooled by using a fixed-effects model. Subgroups (gestational age, type of nebulizer, surfactant type, and dosage) were evaluated. Primary outcome was intubation rate at 72 hours after birth.

RESULTS

Nine studies recruiting 1095 infants met inclusion criteria. SN compared with standard care significantly reduced intubation rate at 72 hours after birth (226 of 565 infants [40.0%] vs 231 of 434 infants [53.2%]; risk ratio [RR]: 0.73, 95% confidence interval [CI]: 0.63-0.84; number needed to treat: 8; 95% CI: 5-14]). Prespecified subgroup analysis identified important heterogeneity: SN was most effective in infants ≥28 weeks' gestation (RR: 0.70, 95% CI: 0.60-0.82), with a pneumatically driven nebulizer (RR: 0.52, 95% CI: 0.40-0.68) and in infants receiving ≥200 mg/kg and animal-derived surfactant (RR: 0.63, 95% CI: 0.52-0.75). No differences in neonatal morbidities or mortality were identified.

LIMITATIONS

Quality of evidence was low owing to risk of bias and imprecision.

CONCLUSIONS

SN reduced the intubation rate in preterm infants with a higher efficacy for specific subgroups. There was no difference in relevant neonatal morbidities or mortality.

Surfactant Administration Through Laryngeal or Supraglottic Airways

Noninvasive ventilation is frequently used in the treatment of infants with respiratory distress syndrome. This practice is often effective in higher gestational age neonates, but can be difficult in those with lower gestational ages as surfactant deficiency can be severe. While noninvasive ventilation avoids the negative effects of intubation and ventilator-induced lung injury, failure of this mode of support does occur with relative frequency and is primarily caused by the poorly compliant, surfactant-deficient lung. Because of the potential problems associated with laryngoscopy and intubation, neonatologists have developed various methods to deliver surfactant in minimally invasive ways with the aim of improving the success of noninvasive ventilation. Methods of minimally invasive surfactant administration include various thin catheter techniques, aerosolization/nebulization, and the use of a laryngeal mask airway/supraglottic airway device. The clinician should recognize that currently the only US Food and Drug Administration-approved device to deliver surfactant is an endotracheal tube and all methods reviewed here are considered off-label use. This review will focus primarily on surfactant administration through laryngeal or supraglottic airways, providing a review of the history of this technique, animal and human trials, and comparison with other minimally invasive techniques. In addition, this review provides a step-by-step instruction guide on how to perform this procedure, including a multimedia tutorial to facilitate learning.

The Intertemporal Role of Respiratory Support in Improving Neonatal Outcomes: A Narrative Review

Defining improvements in healthcare can be challenging due to the need to assess multiple outcomes and measures. In neonates, although progress in respiratory support has been a key factor in improving survival, the same degree of improvement has not been documented in certain outcomes, such as bronchopulmonary dysplasia. By exploring the evolution of neonatal respiratory care over the last 60 years, this review highlights not only the scientific advances that occurred with the application of invasive mechanical ventilation but also the weakness of the existing knowledge. The contributing role of non-invasive ventilation and less-invasive surfactant administration methods as well as of certain pharmacological therapies is also discussed. Moreover, we analyze the cost-benefit of neonatal care-respiratory support and present future challenges and perspectives.

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.

An Update on the Prevention and Management of Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a common morbidity affecting preterm infants and is associated with substantial long-term disabilities. There has been no change in the incidence of BPD over the past 20 years, despite improvements in survival and other outcomes. The preterm lung is vulnerable to injuries occurring as a result of invasive ventilation, hyperoxia, and infections that contribute to the development of BPD. Clinicians caring for infants in the neonatal intensive care unit use multiple therapies for the prevention and management of BPD. Non-invasive ventilation strategies and surfactant administration via thin catheters are treatment approaches that aim to avoid volutrauma and barotrauma to the preterm developing lung. Identifying high-risk infants to receive postnatal corticosteroids and undergo patent ductus arteriosus closure may help to individualize care and promote improved lung outcomes. In infants with established BPD, outpatient management is complex and requires coordination from several specialists and therapists. However, most current therapies used to prevent and manage BPD lack solid evidence to support their effectiveness. Further research is needed with appropriately defined outcomes to develop effective therapies and impact the incidence of BPD.

Surfactant nebulization therapy during NIPPV ventilation in surfactant-deficient newborn piglets

BACKGROUND

In recent years, nasal intermittent positive pressure ventilation (NIPPV) has been growing in popularity as a form of noninvasive ventilation for respiratory support in the initial treatment of neonates with surfactant (SF) deficiency. The combination of this type of ventilation with noninvasive SF administration (by nebulization) is an attractive treatment option for respiratory distress syndrome (RDS)-associated pathophysiology of the neonatal lungs. In this study, we aimed to test the tolerability and efficacy of SF nebulization during NIPPV for the treatment of neonatal RDS.

METHODS

Spontaneously-breathing newborn piglets (n = 6/group) with bronchoalveolar lavage (BAL)-induced RDS were assigned to receive during NIPPV (180 min): poractant alfa (400 mg/kg) via an investigational customized vibrating-membrane nebulizer (eFlow-Neos) or poractant alfa (200 mg/kg) as a bolus using the Insure method or no surfactant (controls).

MEASUREMENT AND RESULTS

We assessed pulmonary, hemodynamic and cerebral effects and performed histological analysis of lung and brain tissue. After repeated BAL, newborn piglets developed severe RDS (F_iO2 : 1, pH < 7.2, P_aCO2  > 70 mmHg, P_aO2 < 70 mmHg, C_dyn  < 0.5 ml/cmH₂ O/kg). In both SF-treated groups, we observed rapid improvement in pulmonary status and also similar hemodynamic, cerebral behavior, and lung and brain injury scores.

CONCLUSION

Our results in newborn piglets with severe BAL-induced RDS show the administration of nebulized poractant alfa using the eFlow-Neos nebulizer during NIPPV to be well tolerated and efficacious, suggesting that this noninvasive SF administration option should be explored further.

Aerosolized Surfactant for Preterm Infants with Respiratory Distress Syndrome

Currently, the administration of surfactant to preterm infants with respiratory distress syndrome (RDS) mainly relies on intratracheal instillation; however, there is increasing evidence of aerosolized surfactant being an effective non-invasive strategy. We present a historical narrative spanning sixty years of development of aerosolization systems. We also offer an overview of the pertinent mechanisms needed to create and manage the ideal aerosolization system, with a focus on delivery, distribution, deposition, and dispersion in the context of the human lung. More studies are needed to optimize treatment with aerosolized surfactants, including determination of ideal dosages, nebulizer types, non-invasive interfaces, and breath synchronization. However, the field is rapidly evolving, and widespread clinical use may be achieved in the near future.

Aerosol drug delivery to spontaneously-breathing preterm neonates: lessons learned

Delivery of medications to preterm neonates receiving non-invasive ventilation (NIV) represents one of the most challenging scenarios for aerosol medicine. This challenge is highlighted by the undersized anatomy and the complex (patho)physiological characteristics of the lungs in such infants. Key physiological restraints include low lung volumes, low compliance, and irregular respiratory rates, which significantly reduce lung deposition. Such factors are inherent to premature birth and thus can be regarded to as the intrinsic factors that affect lung deposition. However, there are a number of extrinsic factors that also impact lung deposition: such factors include the choice of aerosol generator and its configuration within the ventilation circuit, the drug formulation, the aerosol particle size distribution, the choice of NIV type, and the patient interface between the delivery system and the patient. Together, these extrinsic factors provide an opportunity to optimize the lung deposition of therapeutic aerosols and, ultimately, the efficacy of the therapy.

In this review, we first provide a comprehensive characterization of both the intrinsic and extrinsic factors affecting lung deposition in premature infants, followed by a revision of the clinical attempts to deliver therapeutic aerosols to premature neonates during NIV, which are almost exclusively related to the non-invasive delivery of surfactant aerosols. In this review, we provide clues to the interpretation of existing experimental and clinical data on neonatal aerosol delivery and we also describe a frame of measurable variables and available tools, including in vitro and in vivo models, that should be considered when developing a drug for inhalation in this important but under-served patient population.