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

Effect of Nasal Continuous Airway Pressure With and Without Surfactant Administration for the Treatment of Respiratory Distress Syndrome in Preterm Neonates

Background Neonatal respiratory distress syndrome is a common cause of respiratory distress in newborns, often resulting from a lack of surfactant production or premature lung breakdown. The objective of this study was to compare the effect of nasal continuous airway pressure with and without surfactant administration for the treatment of respiratory distress syndrome in preterm neonates. Methodology A comparative analytical study was conducted on 100 neonates (group A continuous positive airway pressure (CPAP) with surfactant = 50 vs. group B CPAP only= 50 ). The group was allocated to the patient according to sequence. In group A, the neonates were given surfactant by the INSURE (intubation, surfactant, extubation) technique via an endotracheal tube with a single dose of 100 mg/kg/dose within the first hours of life followed by CPAP. In group B, the neonates were given only CPAP after birth. At follow-up after 24 hours, pH, pCO2, pO2, positive end-expiratory pressure (PEEP), and FiO2 were documented. All information was recorded on a predesigned questionnaire and results were subjected to statistical analysis to determine the significance of observed differences. Collected data were entered and analyzed using SPSS version 22 (IBM Corp., Armonk, NY, USA). Both groups were compared for mean pH, pCO2, pO2, PEEP, and FiO2 using an independent-sample t-test and effectiveness using a chi-square test. A significant difference was considered when the p-value was ≤0.05. Results Group A had a mean age of 4.84 ± 0.95 hours, while group B had a mean age of 5.5 ± 1.26 hours (p = 0.04). Gender distribution was similar in both groups, with 46.0% males and 54.0% females in group A, and 48.0% males and 52.0% females in group B (p = 0.841). Regarding post-treatment blood gas analysis, group A had a mean pH of 7.30 ± 0.05, and group B had a mean pH of 7.302 ± 0.07. While there was no significant difference in pO2 levels (p = 0.38), there was a substantial difference in pCO2 levels, with group A at 38.26 ± 4.35 and group B at 35.45 ± 4.36 (p = 0.02).CPAP parameters also showed a statistically significant difference in PEEP pCO2, with group A at 4.5 ± 0.73 and group B at 4.16 ± 0.37 (p = 0.004). After treatment, group A exhibited significant improvements in blood gas analysis and CPAP parameters compared to group B. Conclusions The study revealed that both CPAP with and without surfactant treatment effectively treat respiratory distress syndrome in preterm infants, with both being safe, effective, secure, and reducing side effects. However, CPAP treatment without surfactant is a non-invasive and cost-effective option.

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.

Artificial Intelligence-Driven Respiratory Distress Syndrome Prediction for Very Low Birth Weight Infants: Korean Multicenter Prospective Cohort Study

BACKGROUND

Respiratory distress syndrome (RDS) is a disease that commonly affects premature infants whose lungs are not fully developed. RDS results from a lack of surfactant in the lungs. The more premature the infant is, the greater is the likelihood of having RDS. However, even though not all premature infants have RDS, preemptive treatment with artificial pulmonary surfactant is administered in most cases.

OBJECTIVE

We aimed to develop an artificial intelligence model to predict RDS in premature infants to avoid unnecessary treatment.

METHODS

In this study, 13,087 very low birth weight infants who were newborns weighing less than 1500 grams were assessed in 76 hospitals of the Korean Neonatal Network. To predict RDS in very low birth weight infants, we used basic infant information, maternity history, pregnancy/birth process, family history, resuscitation procedure, and test results at birth such as blood gas analysis and Apgar score. The prediction performances of 7 different machine learning models were compared, and a 5-layer deep neural network was proposed in order to enhance the prediction performance from the selected features. An ensemble approach combining multiple models from the 5-fold cross-validation was subsequently developed.

RESULTS

Our proposed ensemble 5-layer deep neural network consisting of the top 20 features provided high sensitivity (83.03%), specificity (87.50%), accuracy (84.07%), balanced accuracy (85.26%), and area under the curve (0.9187). Based on the model that we developed, a public web application that enables easy access for the prediction of RDS in premature infants was deployed.

CONCLUSIONS

Our artificial intelligence model may be useful for preparations for neonatal resuscitation, particularly in cases involving the delivery of very low birth weight infants, as it can aid in predicting the likelihood of RDS and inform decisions regarding the administration of surfactant.

The clinical effects of two non-invasive ventilation modes on premature infants with respiratory distress syndrome: A randomized controlled trial

BACKGROUND

To compare the safety and effectiveness of nasal noninvasive high- frequency oscillatory ventilation (NHFOV) and duo positive airway pressure (DuoPAP) applications in preterm babies with respiratory distress syndrome (RDS).

METHODS

This was a randomized controlled trial. Forty-three premature infants with RDS treated in the neonatal intensive care unit of Huaibei Maternal and Child Health Hospital from January 2020 to November 2021 were selected as the research participants. They were randomly divided into the NHFOV group (n = 22) and DuoPAP group (n = 21). General conditions, including the arterial oxygen partial pressure (PaO2), carbon dioxide partial pressure (PaCO2), oxygenation index (OI), the incidence of apnea at 72 hours, duration of noninvasive respiratory support, maternal high-risk factors, total oxygen consumption time, total gastrointestinal feeding time, and the frequency of intraventricular hemorrhage (IVH), neonatal necrotizing enterocolitis (NEC), and bronchopulmonary dysplasia (BPD) and apnea were compared between the NHFOV group and DuoPAP group at 12 and 24 hours after noninvasive respiratory support.

RESULTS

There was no noteworthy difference between the 2 groups with respect to PaO2, PaCO2, OI, IVH, and NEC and BPD at different nodes (all P > .05).

CONCLUSION

The endpoints of PaO2, PaCO2 and OI and complications of IVH, NEC, BPD and Apnea, and did not reveal any statistical differences between NHFOV and DuoPAP during the respiratory support in preterm babies with RDS.

Notch1 Induces Defective Epithelial Surfactant Processing and Pulmonary Fibrosis

Rationale: Although type II alveolar epithelial cells (AEC2s) are chronically injured in idiopathic pulmonary fibrosis (IPF), they contribute to epithelial regeneration in IPF. Objectives: We hypothesized that Notch signaling may contribute to AEC2 proliferation, dedifferentiation characterized by loss of surfactant processing machinery, and lung fibrosis in IPF. Methods: We applied microarray analysis, kinome profiling, flow cytometry, immunofluorescence analysis, western blotting, quantitative PCR, and proliferation and surface activity analysis to study epithelial differentiation, proliferation, and matrix deposition in vitro (AEC2 lines, primary murine/human AEC2s), ex vivo (human IPF-derived precision-cut lung slices), and in vivo (bleomycin and pepstatin application, Notch1 [Notch receptor 1] intracellular domain overexpression). Measurements and Main Results: We document here extensive SP-B and -C (surfactant protein-B and -C) processing defects in IPF AEC2s, due to loss of Napsin A, resulting in increased intra-alveolar surface tension and alveolar collapse and induction of endoplasmic reticulum stress in AEC2s. In vivo pharmacological inhibition of Napsin A results in the development of AEC2 injury and overt lung fibrosis. We also demonstrate that Notch1 signaling is already activated early in IPF and determines AEC2 fate by inhibiting differentiation (reduced lamellar body compartment, reduced capacity to process hydrophobic SP) and by causing increased epithelial proliferation and development of lung fibrosis, putatively via altered JAK (Janus kinase)/Stat (signal transducer and activator of transcription) signaling in AEC2s. Conversely, inhibition of Notch signaling in IPF-derived precision-cut lung slices improved the surfactant processing capacity of AEC2s and reversed fibrosis. Conclusions: Notch1 is a central regulator of AEC2 fate in IPF. It induces alveolar epithelial proliferation and loss of Napsin A and of surfactant proprotein processing, and it contributes to fibroproliferation.

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.

Neonatal Preterm Respiratory Care in Ukraine: An Observational Study of Outcomes in Relation to Timing and Methods of Surfactant Treatment

OBJECTIVE

Timely and effective noninvasive respiratory support and surfactant administration are the key determinants of clinical outcomes in very preterm infants. The objective of this study was to evaluate the impact of the changes in clinical practice of surfactant administration on clinical outcomes and the incidence of continuous positive airway pressure (CPAP) failure defined as the need for mechanical ventilation (MV) during the first 5 days of life in preterm infants <32 weeks.

STUDY DESIGN

One hundred sixty-five outborn very preterm infants with respiratory distress syndrome (RDS), initially managed on CPAP, were enrolled in a retrospective cohort study. Fifty-two infants treated with surfactant using less invasive or INSURE technique were included in the surfactant group. One hundred thirteen control infants received surfactant only in case of CPAP failure.

RESULTS

The study groups were similar in gestational age, rates of main obstetric complications, and antenatal steroid prophylaxis. The rate of cesarean delivery was significantly higher but birth weight and need for resuscitation were lower in infants from the surfactant group. Fifty-five infants with CPAP failure (49%) received surfactant after initiation of MV in the control group in comparison with 52 (100%) in the surfactant group (p < 0.001). The incidence of CPAP failure was significantly higher in the control group (49 vs. 27%; p < 0.01) and it occurred earlier (median [interquartile range age: 4 [2-5] vs. 47 [36-99] hours, respectively; p < 0.001). Early surfactant administration significantly and independently affected the probability of CPAP failure (adjusted odds ratio: 0.29, 95% confidence interval: 0.13-0.67; p < 0.01). There were no differences in morbidities between the groups, but CPAP failure was significantly associated with higher morbidity and mortality.

CONCLUSION

Adherence to the European RDS guidelines with early rescue, less invasive surfactant administration in very preterm infants decreased the probability of CPAP failure which was significantly associated with higher morbidity and mortality.

KEY POINTS

· Early surfactant decreases the probability of CPAP failure.. · Timing and methods of surfactant administration are important.. · Randomized comparisons of prophylactic LISA and CPAP are needed..

A recipe for a good clinical pulmonary surfactant

The lives of thousands premature babies have been saved along the last thirty years thanks to the establishment and consolidation of pulmonary surfactant replacement therapies (SRT). It took some time to close the gap between the identification of the biophysical and molecular causes of the high mortality associated with respiratory distress syndrome in very premature babies and the development of a proper therapy. Closing the gap required the elucidation of some key questions defining the structure–function relationships in surfactant as well as the particular role of the different molecular components assembled into the surfactant system. On the other hand, the application of SRT as part of treatments targeting other devastating respiratory pathologies, in babies and adults, is depending on further extensive research still required before enough amounts of good humanized clinical surfactants will be available. This review summarizes our current concepts on the compositional and structural determinants defining pulmonary surfactant activity, the principles behind the development of efficient natural animal-derived or recombinant or synthetic therapeutic surfactants, as well as a the most promising lines of research that are already opening new perspectives in the application of tailored surfactant therapies to treat important yet unresolved respiratory pathologies.

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.

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.

Nutritional approach for increasing public health during pandemic of COVID-19: A comprehensive review of antiviral nutrients and nutraceuticals

Background: The novel coronavirus (COVID-19) is considered as the most life-threatening pandemic disease during the last decade. The individual nutritional status, though usually ignored in the management of COVID-19, plays a critical role in the immune function and pathogenesis of infection. Accordingly, the present review article aimed to report the effects of nutrients and nutraceuticals on respiratory viral infections including COVID-19, with a focus on their mechanisms of action. Methods: Studies were identified via systematic searches of the databases including PubMed/ MEDLINE, ScienceDirect, Scopus, and Google Scholar from 2000 until April 2020, using keywords. All relevant clinical and experimental studies published in English were included. Results: Protein-energy malnutrition (PEM) is common in severe respiratory infections and should be considered in the management of COVID-19 patients. On the other hand, obesity can be accompanied by decreasing the host immunity. Therefore, increasing physical activity at home and a slight caloric restriction with adequate intake of micronutrients and nutraceuticals are simple aids to boost host immunity and decrease the clinical manifestations of COVID-19. Conclusion: The most important nutrients which can be considered for COVID-19 management are vitamin D, vitamin C, vitamin A, folate, zinc, and probiotics. Their adequacy should be provided through dietary intake or appropriate supplementation. Moreover, adequate intake of some other dietary agents including vitamin E, magnesium, selenium, alpha linolenic acid and phytochemicals are required to maintain the host immunity.

Association of Adherence to Surfactant Best Practice Uses With Clinical Outcomes Among Neonates in Sweden

IMPORTANCE

While surfactant therapy for respiratory distress syndrome (RDS) in preterm infants has been evaluated in clinical trials, less is known about how surfactant is used outside such a framework.

OBJECTIVE

To evaluate registered use, off-label use, and omissions of surfactant treatment by gestational age (GA) and associations with outcomes, mainly among very preterm infants (GA <32 weeks).

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study used registry data for 97 377 infants born in Sweden between 2009 and 2018. Infants did not have malformations and were admitted for neonatal care. Data analysis was conducted from June 2019 to June 2020.

EXPOSURES

Timing and number of surfactant administrations, off-label use, and omission of use. Registered use was defined by drug label (1-3 administrations for RDS). Omissions were defined as surfactant not administered despite mechanical ventilation for RDS.

MAIN OUTCOME AND MEASURES

In-hospital survival, pneumothorax, intraventricular hemorrhage grade 3 to 4, duration of mechanical ventilation, use of postnatal systemic corticosteroids for lung disease, treatment with supplemental oxygen at 28 days' postnatal age and at 36 weeks' postmenstrual age. Odds ratios (ORs) were calculated and adjusted for any prenatal corticosteroid treatment, cesarean delivery, GA, infant sex, Apgar score at 10 minutes, and birth weight z score of less than -2.

RESULTS

In total, 7980 surfactant administrations were given to 5209 infants (2233 [42.9%] girls; 2976 [57.1%] boys): 629 (12.1%) born at full term, 691 (13.3%) at 32 to 36 weeks' GA, 1544 (29.6%) at 28 to 31 weeks' GA, and 2345 (45.0%) at less than 28 weeks' GA. Overall, 977 infants (18.8%) received off-label use. In 1364 of 3508 infants (38.9%) with GA of 22 to 31 weeks, the first administration of surfactant was given more than 2 hours after birth, and this was associated with higher odds of pneumothorax (adjusted OR [aOR], 2.59; 95% CI, 1.76-3.83), intraventricular hemorrhage grades 3 to 4 (aOR, 1.71; 95% CI, 1.23-2.39), receipt of postnatal corticosteroids (aOR, 1.57; 95% CI, 1.22-2.03), and longer duration of assisted ventilation (aOR, 1.34; 95% CI, 1.04-1.72) but also higher survival (aOR, 1.45; 95% CI, 1.10-1.91) than among infants treated within 2 hours of birth. In 146 infants (2.8%), the recommended maximum of 3 surfactant administrations was exceeded but without associated improvements in outcome. Omission of surfactant treatment occurred in 203 of 3551 infants (5.7%) who were receiving mechanical ventilation and was associated with lower survival (aOR, 0.49; 95% CI, 0.30-0.82). In full-term infants, 336 (53.4%) of those receiving surfactant had a diagnosis of meconium aspiration syndrome. Surfactant for meconium aspiration was not associated with improved neonatal outcomes.

CONCLUSIONS AND RELEVANCE

In this study, adherence to best practices and labels for surfactant use in newborn infants varied, with important clinical implications for neonatal outcomes.

Weight Is More Accurate than Gestational Age When Estimating the Optimal Endotracheal Tube Depth in Neonates

Determining the optimal endotracheal tube (ETT) depth in neonates remains challenging for neonatologists. The guideline for optimal ETT depth is based on the patients’ weight or gestational age. However, there is a discrepancy in the suggested ETT depth between these two parameters. The aim of this retrospective study was to compare the recommended weight-based and age-based formulas for optimal ETT depth and obtain the optimal reference before intubation. Participants were assigned to group 1 if the recommended ETT insertion depth based on weight was concordant with the recommended depth based on gestational age, and to group 2 if the weight and age-based depth recommendations were discordant. After exclusion, 180 patients were included in the analysis. Results indicated that the predicted ETT depth suggested by age required more adjustment than by weight (p < 0.05). Furthermore, the required adjustment in the weight-based formula was smaller than the age-based formula (p < 0.05). Multivariate linear regression analysis revealed that weight was the key factor affecting the optimal depth (p < 0.001). These results imply that when there is a discrepancy in ETT depth between the weight-based and age-based recommendation, the weight-based one will be more accurate than the age-based one.

Guidelines for surfactant replacement therapy in neonates

Surfactant replacement therapy (SRT) plays a pivotal role in the management of neonates with respiratory distress syndrome (RDS) because it improves survival and reduces respiratory morbidities. With the increasing use of noninvasive ventilation as the primary mode of respiratory support for preterm infants at delivery, prophylactic surfactant is no longer beneficial. For infants with worsening RDS, early rescue surfactant should be provided. While the strategy to intubate, give surfactant, and extubate (INSURE) has been widely accepted in clinical practice, newer methods of noninvasive surfactant administration, using thin catheter, laryngeal mask airway, or nebulization, are being adopted or investigated. Use of SRT as an adjunct for conditions other than RDS, such as meconium aspiration syndrome, may be effective based on limited evidence.

Les directives pour le traitement par surfactant exogène chez le nouveau-né

Le traitement par surfactant exogène joue un rôle essentiel dans la prise en charge des nouveau-nés atteints du syndrome de détresse respiratoire (maladie des membranes hyalines) parce qu’il améliore la survie et limite les troubles respiratoires. Puisque la ventilation non invasive est de plus en plus utilisée comme principal mode d’assistance respiratoire chez le nouveau-né prématuré à la naissance, l’administration prophylactique de surfactant n’est plus bénéfique. L’administration précoce de surfactant sous forme de traitement de rattrapage est préconisée chez les nouveau-nés dont le syndrome de détresse respiratoire s’aggrave. La stratégie qui consiste à intuber, administrer du surfactant, puis extuber (INSURE) est largement acceptée en pratique clinique, mais des méthodes non invasives plus récentes à l’aide d’un cathéter fin, d’un masque laryngé ou d’un nébuliseur sont en cours d’adoption ou d’exploration. Selon des données limitées, un traitement d’appoint par surfactant exogène pourrait être efficace pour traiter d’autres affections que le syndrome de détresse respiratoire, telles que le syndrome d’aspiration méconiale.

Does surfactant nebulization prevent early intubation in preterm infants? A protocol for a systematic review and meta-analysis

BACKGROUND

Respiratory distress syndrome (RDS) is the most common cause of respiratory failure in preterm infants. Treatment consists of respiratory support and exogenous surfactant administration. Commonly, surfactant is administered intratracheally. However, this requires airway instrumentation and subsequent fluid instillation which may be harmful. Surfactant nebulization (SN) may offer a safe and effective alternative for surfactant administration, but the clinical efficacy is not yet established. Thus, this systematic review and meta-analysis of randomized controlled trials will summarize the available evidence to determine the effectiveness and safety of SN for the prevention of intubation and subsequent mechanical ventilation at 72 h after birth.

METHODS

A systematic literature search in Medline, Embase, and The Cochrane Library will be performed, and all randomized controlled trials (RCTs) and quasi-RCTs from published articles, presentations, and trial registries will be included in this meta-analysis. Titles and abstracts of all records identified in the search will be screened by two reviewers independently. Data on preterm infants (≤ 37 weeks) receiving nebulized surfactant in the first 72 h after birth for the treatment or prevention of RDS will be evaluated. Primary outcome is the intubation rate by 72 h after birth, and secondary outcomes include peridosing safety effects as well as major neonatal morbidities. Risk of bias will be assessed using the revised Cochrane ROB tool, and subgroup analyses will be performed to evaluate potential confounding factors. Publication bias will be assessed by examining a funnel plot. The meta-analysis will be performed using a fixed-effects model.

DISCUSSION

This review will provide an evidence-based tool for information about surfactant nebulization, illustrating the current knowledge and hopefully revealing potential novel avenues for researchers and clinicians alike.

SYSTEMATIC REVIEW REGISTRATION

This review is registered with the publicly available resource PROSPERO ( CRD42020175625 ).

The Effect of Exogenous Surfactant on Moderate and Severe Stages of COVID-19 Induced ARDS: the Pilot Study of a Clinical Trial

COVID-19 pandemic has created a global health challenge. Many pharmaceuticals have been repurposed as potential treatments, though many have not been promising. Due to the inflammatory and destructive effects of the virus on alveolar cells, the effect of exogenous surfactant was assessed as a potential treatment of lung dysfunction in COVID-19 patients. In this pilot study of the clinical trial, 49 patients aged 35-80 years with COVID-19 admitted in ICU entered the study (22 patients intubated and 23 had face masks; 4 patients in the control arm). The treatment arm patients received two consecutive doses of surfactant. P/F ratio (based on serial blood gas analyses before and 12 hours after 2 doses of surfactant) and also, clinical outcomes were assessed.in COVID-19 adult patients, surfactant significantly improved pulmonary P/F ratio both in intubated and face mask COVID-19 patients (increasing from 119.2 ± 51.7 to 179.4 ± 115.5). The rate of extubation was much better than similar country-wide studies. Surfactant significantly alleviates the respiratory status in moderate to severe COVID-19 ARDS with two consecutive 100 mg doses of surfactant (with 6 hours' interval) though previous studies have been controversial, regarding the effect of surfactant in general forms of ARDS. Higher doses might have better effects, mandating more trials.

Aerosolized Beractant in neonatal respiratory distress syndrome: A randomized fixed-dose parallel-arm phase II trial

PURPOSE

There is increasing research into novel techniques of administering surfactant to preterm infants (PTIs) with respiratory distress syndrome (RDS) receiving non-invasive respiratory support (NIRS). Although aerosolized surfactant (AS) is promising in PTIs receiving NIRS, the optimal surfactant dose and formulation, drug-device combination and patient profile is not known. The objective of this randomized clinical trial was to investigate the feasibility, safety, efficacy and impact of four dosing schedules of AS using two nebulizers in PTIs with RDS stratified by gestational age (GA).

METHODS

PTIs with RDS receiving pre-defined NIRS for ≤8 h were assigned to 4 A S dosing schedules and 2 nebulizers within three GA strata (I = 24^0/7-28^6/7, II = 29^0/7-32^6/7, III = 33^0/7-36^6/7 weeks). There was no contemporaneous control group; at the recommendation of the Data Monitoring Committee, data was collected retrospectively for control infants.

RESULTS

Of 149 subjects that received AS, the median age at initiation of the 1st dose and duration was 5.5 and 2.4 h respectively. There were 29 infants in stratum I, and 60 each in strata II and III. Of infants <32 weeks GA, 94% received caffeine prior to AS. Fifteen infants (10%) required intubation within 72 h; the rates were not significantly different between GA strata, dosing schedules and nebulizers for infants who received aerosolized surfactant. Compared to retrospective controls, infants who received AS were less likely to need intubation within 72 h in both the intention-to-treat (32% vs. 11%) and the per-protocol (22% vs. 10%) analyses (p < 0.05) with GA stratum specific differences. AS was well tolerated by infants and clinical caregivers. Commonest adverse events included surfactant reflux from nose and mouth (18%), desaturations (11%), and increased secretions (7%).

CONCLUSIONS

We have demonstrated the feasibility, absence of serious adverse events and short-term efficacy of four dosing schedules of AS in the largest Phase II clinical trial of PTIs 24-36 weeks' GA with RDS receiving NIRS (ClinicalTrials.gov NCT02294630). The commonest adverse events noted were surfactant reflux and desaturations; no serious adverse effects were observed. Infants who received AS were less likely to receive intubation within 72 h compared to historical controls. AS is a promising new therapy for PTIs with RDS.

Nebulized versus invasively delivered surfactant therapy for neonatal respiratory distress syndrome: A systematic review and meta-analysis

BACKGROUND

Pulmonary surfactant (PS) is commonly used for the treatment of neonatal respiratory distress syndrome (NRDS), several randomized controlled trials (RCTs) have evaluated the role of nebulized versus invasively delivered PS, yet the results remained inconsistent. Therefore, we aimed to conduct this meta-analysis to evaluate the effects and safety of nebulized versus invasively delivered PS in the treatment of NRDS.

METHODS

We searched PubMed et al databases from inception date to May 15, 2020 for RCTs that compared nebulized vs invasively delivered PS. Two authors independently screened the studies and extracted data from the published articles. Summary odd ratios (OR) or mean differences (MDs) with 95% confidence intervals (CIs) were calculated for each outcome by means of fixed- or random-effects model.

RESULTS

Two RCTs with a total of 95 preterm neonates were identified, with 48 neonates received PS nebulization and 47 neonates undergone invasive PS administration. There was no significant difference in the SpO2 level (MD = -0.44, 95% CI -6.01 to 5.12) and the A/APaO2 level (MD = 0.01, 95% CI -0.02 to 0.05) 1 hour after treatment among 2 groups. But the duration of mechanical ventilation in the nebulization groups was significantly less than that of invasive group (MD = -30.70, 95% CI -41.45 to 19.95).

CONCLUSIONS

Given the limited evidences, the effects and safety of nebulized versus invasively delivered PS still need further verification.

A survey on criteria for intubation in moderate to late preterm infants with respiratory distress

BACKGROUND

Majority of preterm infants do well with continuous positive airway pressure (CPAP) as the sole respiratory management; but some require endotracheal intubation and surfactant administration. While intubation is needed predominantly in extremely preterm infants (<28 weeks); some of the more mature preterm infants also require it. Currently, there are no clear guidelines regarding indications for endotracheal intubation in such infants.

AIMS

To understand the current practice regarding "criteria for intubation" in moderate to late preterm infants with respiratory distress.

METHODS

A survey of neonatologists in Australia New Zealand Neonatal Network (ANZNN) was conducted between April and June 2019.

RESULTS

At least one neonatologist each from 29 of the 30 tertiary ANZNN Neonatal Intensive Care Units (NICUs) responded to the survey. In total, 118/200 (59%) neonatologists responded. The most common criteria for intubation were CPAP = 8 cmH₂ O (61%), pH < 7.2 (55%), pCO₂  > 70 mmHg (48%), FiO₂  > 40% (40%), chest retractions (48%), more than two episodes of apnea requiring intervention (54%), and chest X-ray (CXR) showing moderate-severe hyaline membrane disease (HMD, 49%).

CONCLUSION

While there were variations in practice, nearly 50% of the neonatologists shared a common threshold with regards to the CPAP level, FiO₂ , blood gas parameters, and clinical and radiological findings. The results of this survey will help in designing future randomized controlled trials (RCTs) on this subject.

[Risk factors for minimally invasive surfactant administration failure in preterm infants with respiratory distress syndrome]

OBJECTIVE

To identify risk factors for minimally invasive surfactant administration (MISA) failure in the treatment of preterm infants with respiratory distress syndrome (RDS) and the influence of MISA failure on neonatal outcome.

METHODS

A retrospective analysis was performed for the clinical data of 148 preterm infants with a gestational age of ≤32 weeks and a clinical diagnosis of RDS, who were admitted to the neonatal intensive care unit of eight tertiary hospitals in Beijing, Tianjin and Hebei Province from July 1, 2017 to December 31, 2018 and were treated with MISA (bovine pulmonary surfactant, PS). According to whether MISA failure (defined as the need for mechanical ventilation within 72 hours after MISA) was observed, the infants were divided into two groups: MISA failure group (n=16) and MISA success (n=132). A logistic regression analysis was used to investigate the risk factors for MISA failure and its influence on neonatal outcome.

RESULTS

The MISA failure rate was 10.8% (16/148). The logistic regression analysis showed that a high incidence rate of grade >II RDS before PS administration, low mean arterial pressure and high pulse pressure before administration, a low dose of initial PS administration, and long injection time and operation time were the risk factors for MISA failure (OR=5.983, 1.210, 1.183, 1.055, 1.036, and 1.058 respectively, P<0.05). After the control for the above risk factors, the logistic regression analysis showed that the MISA failure group had a significantly higher incidence rate of bronchopulmonary dysplasia (BPD) (OR=8.537, P<0.05).

CONCLUSIONS

A high grade of RDS, a low mean arterial pressure, and a high pulse pressure before administration are independent risk factors for MISA failure, and a low dose of initial PS administration, a long injection time, and a long operation time may increase the risk of MISA failure. MISA failure may increase the incidence rate of BPD in preterm infants.

Minimally invasive surfactant therapy failure: risk factors and outcome

OBJECTIVE

To evaluate incidence of minimally invasive surfactant therapy (MIST) failure, identify risk factors and assess the impact of MIST failure on neonatal outcome.

DESIGN

Retrospective cohort study. MIST failure was defined as need for early mechanical ventilation (<72 hours of life). Multivariate logistic regression analysis was performed to identify risk factors for MIST failure and compare outcomes between groups.

SETTING

Two tertiary neonatal intensive care centres in the Netherlands.

PATIENTS

Infants born between 24 weeks' and 31 weeks' gestational age (GA) (n=185) with MIST for respiratory distress syndrome.

INTERVENTIONS

MIST procedure with poractant alfa (100-200 mg/kg).

MAIN OUTCOME MEASURES

Continuous positive airway pressure (CPAP) failure after MIST in the first 72 hours of life.

RESULTS

30% of the infants failed CPAP after MIST. In a multivariate logistic regression analysis, four risk factors were independently associated with failure: GA <28 weeks, C reactive protein ≥10 mg/L, absence of antenatal corticosteroids and lower surfactant dose. Infants receiving 200 mg/kg surfactant had a failure rate of 14% versus 35% with surfactant dose <200 mg/kg. Mean body temperature was 0.4°C lower at neonatal intensive care unit admission and before the procedure in infants with MIST failure.Furthermore, MIST failure was independently associated with an increased risk of severe intraventricular haemorrhage.

CONCLUSION

We observed moderate MIST failure rates in concordance with the results of earlier studies. Absence of corticosteroids and lower surfactant dose are risk factors for MIST failure that may be modifiable in order to improve MIST success and patient outcome.

From bench to bedside: in vitro and in vivo evaluation of a neonate-focused nebulized surfactant delivery strategy

Background

Non-invasive delivery of nebulized surfactant has been a neonatology long-pursued goal. Nevertheless, the clinical efficacy of nebulized surfactant remains inconclusive, in part, due to the great technical challenges of depositing nebulized drugs in the lungs of preterm infants. The aim of this study was to investigate the feasibility of delivering nebulized surfactant (poractant alfa) in vitro and in vivo with an adapted, neonate-tailored aerosol delivery strategy.

Methods

Particle size distribution of undiluted poractant alfa aerosols generated by a customized eFlow-Neos nebulizer system was determined by laser diffraction. The theoretical nebulized surfactant lung dose was estimated in vitro in a clinical setting replica including a neonatal continuous positive airway pressure (CPAP) circuit, a cast of the upper airways of a preterm neonate, and a breath simulator programmed with the tidal breathing pattern of an infant with mild respiratory distress syndrome (RDS). A dose-response study with nebulized surfactant covering the 100–600 mg/kg nominal dose-range was conducted in RDS-modelling, lung-lavaged spontaneously-breathing rabbits managed with nasal CPAP. The effects of nebulized poractant alfa on arterial gas exchange and lung mechanics were assessed. Exogenous alveolar disaturated-phosphatidylcholine (DSPC) in the lungs was measured as a proxy of surfactant deposition efficacy.

Results

Laser diffraction studies demonstrated suitable aerosol characteristics for inhalation (mass median diameter, MMD = 3 μm). The mean surfactant lung dose determined in vitro was 13.7% ± 4.0 of the 200 mg/kg nominal dose. Nebulized surfactant delivered to spontaneously-breathing rabbits during nasal CPAP significantly improved arterial oxygenation compared to animals receiving CPAP only. Particularly, the groups of animals treated with 200 mg/kg and 400 mg/kg of nebulized poractant alfa achieved an equivalent pulmonary response in terms of oxygenation and lung mechanics as the group of animals treated with instilled surfactant (200 mg/kg).

Conclusions

The customized eFlow-Neos vibrating-membrane nebulizer system efficiently generated respirable aerosols of undiluted poractant alfa. Nebulized surfactant delivered at doses of 200 mg/kg and 400 mg/kg elicited a pulmonary response equivalent to that observed after treatment with an intratracheal surfactant bolus of 200 mg/kg. This bench-characterized nebulized surfactant delivery strategy is now under evaluation in Phase II clinical trial (EUDRACT No.:2016–004547-36).

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1096-9) contains supplementary material, which is available to authorized users.

History of Pulmonary Surfactant Replacement Therapy for Neonatal Respiratory Distress Syndrome in Korea

Neonatal respiratory distress syndrome (RDS) is a disease that is unique to newborn infants. It is caused by a deficiency of pulmonary surfactant (PS), which is usually ready to be activated around the perinatal period. Until RDS was more clearly understood, it was not known why premature infants died from respiratory failure, although pathology revealed hyaline membranes in the alveoli. Surprisingly, the era of PS replacement therapy began only relatively recently. The first clinical trial investigating neonatal RDS was conducted in 1980. Since then, newborn survival has improved dramatically, which has led to significant advances in the field of neonatology. The present comprehensive review addresses PS, from its discovery to the application of artificial PS in newborns with RDS. It also reviews the history of PS in Korea, including its introduction, various commercial products, present and past research, newborn registries, and health insurance issues. Finally, it describes the inception of the Korean Society of Neonatology and future directions of research and treatment.

Phospholipid components of the synthetic pulmonary surfactant CHF5633 probed by fluorescence spectroscopy

CHF5633 (Chiesi Farmaceutici, Italy) is a synthetic pulmonary surfactant currently under clinical development for the treatment of Respiratory Distress Syndrome in premature infants. The product is composed of phospholipids in liposomal organization, together with two peptide analogues of human surfactant proteins B and C. Phospholipids in liposomes can undergo oxidation of unsaturated lipids and hydrolysis, with formation of fatty acids and lysolipids, both affecting the physico-chemical properties of the formulation. We exploited two fluorescence probes, Prodan and ADIFAB, to evaluate the stability of the phospholipid components of CHF5633. While Prodan enters the phospholipid bilayer and probes the polarity of this environment, ADIFAB binds free fatty acids in the aqueous phase, allowing to determine their concentration. Changes of Prodan fluorescence emission indicated an increase in the polarity of the phospholipid bilayer as a function of time. This behavior is coupled with an increase in fatty acids concentration in the aqueous phase, as determined by ADIFAB, and an increase in lysolipids concentration, as determined by HPLC-MS. Prodan and ADIFAB resulted efficient probes to monitor phospholipids hydrolysis in liposomes, reporting an increased stability of CHF5633 at pH values higher than 6.5.

The scope and extent of exogenous surfactant utilization in Nigerian health care facilities: benefits of its regular use to outcome of premature babies

Background: Surfactant replacement therapy (SRT) is the standard of care in developed countries. Poor access to surfactant limits its use in low resource settings. The extent of its use and the effect of its regular use on the preterm in such settings is unknown.Objective: This study assessed the extent of exogenous surfactant utilization in Nigerian tertiary care facilities and the benefits of its regular use to the preterm population.Methods: A two-phase cross-sectional study design evaluated the response from a respondent administered structured questionnaire addressed to health care providers from 54 centers and a targeted assessment of the outcome of the regular use of exogenous surfactant in a tertiary care facility from January 2014 to December 2016.Results: SRT was available in 16.7% of 54 units evaluated nationally; three (33.3%) were located in south-south and south-west respectively, 2 (22.2%) in southeast and one (11.1%) in north-central regions of the country. Twenty-two percent of the units were private centers, 77.8% were public tertiary care facilities. Four (44.4%) units provide SRT as the standard of care while five (66.6%) provide the service on request. One thousand one hundred twenty babies were admitted to the audited tertiary facility with 550 (49%) as preterms. Only 2.72% received surfactant replacement therapy. Sixty-six percent of recipients survived whilst 33.3% died. Respiratory support positively enhanced outcome in recipients of surfactant therapy.Conclusion: There is a limited use of surfactant nationally. Its use seemed to have improved survival.

Vitamin A Supplementation by Endotracheal Application of a Nano-encapsulated Preparation Is Feasible in Ventilated Preterm Lambs

BACKGROUND

Vitamin A (VA) is crucial for lung growth and development. In premature infants, inadequate VA levels are associated with an increased risk of bronchopulmonary dysplasia (BPD). Intramuscular VA supplementation has been shown to decrease the incidence of BPD, but is not widely used in the clinical setting due to concerns about feasibility and pain. We studied VA kinetics, distribution, and the induction of early genetic expression of retinoid homeostatic genes in the lung after endotracheal and intravenous application in a preterm lamb model.

METHODS

Lambs were delivered prematurely after 85% of gestation, intubated, and ventilated for 3 hours. The animals were randomized to receive no VA ("control"), a bolus of VA intravenously ("i.v."), or VA endotracheally directly after administration of surfactant ("e.t.").

RESULTS

Animals treated with VA endotracheally directly after administration of surfactant showed significant increases of VA in serum and lung compared to controls. Animals treated with a bolus of VA intravenously showed significant increases of VA in serum, lung, and liver; however, peak serum concentrations and mRNA levels of homeostatic genes raised concerns about toxicity in this group.

CONCLUSIONS

Endotracheal VA supplementation in preterm lambs is feasible and might offer advantages in comparison to i.v. Further studies are warranted to explore biological effects in the context of BPD.