Evolution of surfactant therapy for respiratory distress syndrome: past, present, and future

PC (16:0/14:0) ameliorates hyperoxia-induced bronchopulmonary dysplasia by upregulating claudin-1 and promoting alveolar type II cell repair

Bronchopulmonary dysplasia (BPD) remains a significant challenge in neonatal care, the pathogenesis of which potentially involves altered lipid metabolism. Given the critical role of lipids in lung development and the injury response, we hypothesized that specific lipid species could serve as therapeutic agents in BPD. This study aimed to investigate the role of the lipid Phosphatidylcholine (PC) (16:0/14:0) in modulating BPD pathology and to elucidate its underlying mechanisms of action. Our approach integrated in vitro and in vivo methodologies to assess the effects of PC (16:0/14:0) on the histopathology, cellular proliferation, apoptosis, and molecular markers in lung tissue. In a hyperoxia-induced BPD rat model, we observed a reduction in alveolar number and an enlargement in alveolar size, which were ameliorated by PC (16:0/14:0) treatment. Correspondingly, in BPD cell models, PC (16:0/14:0) intervention led to increased cell viability, enhanced proliferation, reduced apoptosis, and elevated surfactant protein C (SPC) expression. RNA sequencing revealed significant gene expression differences between BPD and PC (16:0/14:0) treated groups, with a particular focus on Cldn1 (encoding claudin 1), which was significantly enriched in our analysis. Our findings suggest that PC (16:0/14:0) might protect against hyperoxia-induced alveolar type II cell damage by upregulating CLDN1 expression, potentially serving as a novel therapeutic target for BPD. This study not only advances our understanding of the role of lipids in BPD pathogenesis, but also highlights the significance of PC (16:0/14:0) in the prevention and treatment of BPD, offering new avenues for future research and therapeutic development.

Surfactant for the treatment of respiratory distress syndrome in very low birth weight infants at a level 2 hospital: A descriptive retrospective cohort study - safety and efficacy

Respiratory distress syndrome (RDS) is common and is a leading cause of death in pre-term infants. The purpose of our study is to describe the demographics and incidence of adverse events in very low birth weight (VLBW) pre-term infants with RDS treated with surfactant at George, a level 2 Hospital in the Western Cape Province of South Africa. This was a retrospective observational study. We conducted an electronic folder review of infants with a birth weight of 800-1200 g treated during the study period 2017-2019 at George Regional Hospital. Outborn infants and those with congenital abnormalities were excluded. The total number of patients included in the study was 66. The mortality rate was 25.8% (17/66). The incidence of bronchopulmonary dysplasia was 6% (4/66). Our study showed that the outcomes of VLBW infants treated with surfactant at level 2 hospitals are comparable to South African central hospitals.

Less Invasive Surfactant Administration Compared to Intubation, Surfactant, Rapid Extubation Method in Preterm Neonates: An Umbrella Review

INTRODUCTION

In spontaneously breathing neonates, surfactant can be administered via thin catheter while enabling the own breathing (less invasive surfactant administration [LISA]). Alternatively, the neonate is intubated for surfactant delivery (intubation, surfactant, rapid extubation [INSURE]). Thus, the aim was to provide an overview of the efficacy of the LISA compared to INSURE.

METHODS

We performed an umbrella review of previous meta-analyses including randomized controlled trials. We searched PubMed, Scopus, and Web of Science in July 2023. Two authors screened the search results, and systematic reviews with meta-analyses that focused on LISA versus INSURE were included. One author extracted, and another author validated the extracted data. AMSTAR-2 and ROBIS evaluations were performed by two authors independently.

RESULTS

A total of 9 systematic reviews with meta-analyses were included. The quality according to AMSTAR-2 was high in one, moderate in one, low in three, and critically low in four. According to ROBIS, the risk of bias was low in three and high in six of the reviews. LISA was more effective than INSURE in preventing mechanical ventilation (8/8 reviews), death or BPD (4/4 reviews), death (3/9 reviews), and BPD (3/9 reviews).

CONCLUSIONS

All the included systematic reviews and meta-analyses reported LISA to be more effective than INSURE in terms of need for mechanical ventilation and death or BPD. However, the quality of the published systematic reviews has been mostly deficient. Future systematic reviews should focus on reporting quality.

Deep Learning Model for Prediction of Bronchopulmonary Dysplasia in Preterm Infants Using Chest Radiographs

Bronchopulmonary dysplasia (BPD) is common in preterm infants and may result in pulmonary vascular disease, compromising lung function. This study aimed to employ artificial intelligence (AI) techniques to help physicians accurately diagnose BPD in preterm infants in a timely and efficient manner. This retrospective study involves two datasets: a lung region segmentation dataset comprising 1491 chest radiographs of infants, and a BPD prediction dataset comprising 1021 chest radiographs of preterm infants. Transfer learning of a pre-trained machine learning model was employed for lung region segmentation and image fusion for BPD prediction to enhance the performance of the AI model. The lung segmentation model uses transfer learning to achieve a dice score of 0.960 for preterm infants with ≤ 168 h postnatal age. The BPD prediction model exhibited superior diagnostic performance compared to that of experts and demonstrated consistent performance for chest radiographs obtained at ≤ 24 h postnatal age, and those obtained at 25 to 168 h postnatal age. This study is the first to use deep learning on preterm chest radiographs for lung segmentation to develop a BPD prediction model with an early detection time of less than 24 h. Additionally, this study compared the model's performance according to both NICHD and Jensen criteria for BPD. Results demonstrate that the AI model surpasses the diagnostic accuracy of experts in predicting lung development in preterm infants.

Construction and evaluation of neonatal respiratory failure risk prediction model for neonatal respiratory distress syndrome

BACKGROUND

Neonatal respiratory distress syndrome (NRDS) is a common respiratory disease in preterm infants, often accompanied by respiratory failure. The aim of this study was to establish and validate a nomogram model for predicting the probability of respiratory failure in NRDS patients.

METHODS

Patients diagnosed with NRDS were extracted from the MIMIC-iv database. The patients were randomly assigned to a training and a validation cohort. Univariate and stepwise Cox regression analyses were used to determine the prognostic factors of NRDS. A nomogram containing these factors was established to predict the incidence of respiratory failure in NRDS patients. The area under the receiver operating characteristic curve (AUC), receiver operating characteristic curve (ROC), calibration curves and decision curve analysis were used to determine the effectiveness of this model.

RESULTS

The study included 2,705 patients with NRDS. Univariate and multivariate stepwise Cox regression analysis showed that the independent risk factors for respiratory failure in NRDS patients were gestational age, pH, partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), hemoglobin, blood culture, infection, neonatal intracranial hemorrhage, Pulmonary surfactant (PS), parenteral nutrition and respiratory support. Then, the nomogram was constructed and verified.

CONCLUSIONS

This study identified the independent risk factors of respiratory failure in NRDS patients and used them to construct and evaluate respiratory failure risk prediction model for NRDS. The present findings provide clinicians with the judgment of patients with respiratory failure in NRDS and help clinicians to identify and intervene in the early stage.

Trends in neonatal morbidity and mortality for very low birthweight infants: a 20-year single-center experience

OBJECTIVE

To describe trends in mortality and morbidity rates of very low birth weight infants as well as their pre-, peri- and postnatal characteristics over a period of 20 years' time.

METHODS

Retrospective study in all very low birth weight infants admitted to the neonatal intensive care unit of the University Hospitals Ghent from 1 January 2000, to 31 December 2020. Mortality was the primary outcome variable with major morbidities being co-primary outcome variables. Pre-, peri- and postnatal characteristics are secondary outcome variables. We compared pre-, peri- and postnatal characteristics, as well as major morbidities between different groups with comparable rates of mortality.

RESULTS

We included a total of 2037 very low birth weight infants and divided them in 3 epochs based on stepwise reductions in mortality in 2008 and 2013: 2000-2007 (n = 718), 2008-2012 (n = 506) and 2013-2020 (n = 813). Mortality decreased significantly over the years in all gestational ages, but predominantly in those with the youngest gestational age. Changes in obstetric and neonatal care were observed over time. Most significant changes were the increased use of antenatal corticosteroids, magnesium sulfate and surfactant. Intraventricular hemorrhage grade III/IV decreased significantly in all gestational ages. Significant increase in retinopathy of prematurity was observed. Bronchopulmonary dysplasia at 36 weeks and discharge home with oxygen is increasing in the total group. In those born below 26 weeks a slight increase in all major morbidities was observed especially of patent ductus arteriosus and retinopathy of prematurity. Increase of all other major morbidities seems to stabilize in epoch 3. The number of infants surviving without any major morbidity increases to almost 1/2 in all very low birth weight infants and to 1/10 in those born 24-25 weeks gestation.

CONCLUSION

Analysis of the real-life experience showed that survival in very low birth weight infants significantly increased over time. Evolution of major morbidities will have to be carefully watched in the future.

Cumulative evidence of the genetic association between SP-B C1580T polymorphisms and risk of neonatal respiratory distress syndrome

Objective: Surfactant protein SP-B, an important protein in pulmonary surfactant, is required for the stabilization of surfactant films in the lung and maintenance of postnatal lung function. Although the association between SP-B polymorphisms and the risk of neonatal respiratory distress syndrome (RDS) has been evaluated, the results have been inconsistent. We investigated the association between SP-B polymorphisms and the risk of neonatal RDS.Methods: Relevant studies were systematically searched in PubMed, EMBASE, Web of Science, and Chinese National Knowledge Infrastructure (CNKI) electronic databases until June 2022. Data were collected independently by two reviewers and converted to odds ratios (ORs) with 95% confidence intervals (CIs). Meta-analysis, subgroup analysis, sensitivity analysis, and publication bias assessment were performed using Stata 12.1 software and Review Manager 5.3.Results: Fourteen studies were included. SP-B C1580T polymorphism was significantly associated with neonatal RDS in five genetic models (T vs. C: OR = 0.70, 95% CI 0.57-0.86, I² = 78%; TT vs. CC: OR = 0.63, 95% CI 0.53-0.86, I² = 39%; CT vs. CC: OR = 0.65, 95% CI 0.50-0.84, I² = 54%; TT + CT vs. CC: OR = 0.62, 95% CI 0.49-0.78, I² = 59%; TT vs. CC + CT: OR = 0.78, 95% CI 0.67-0.91, I² = 43%). The CT and TT genotypes may decrease the risk of RDS in neonates. Subgroup analyses revealed that the association of SP-B C1580T polymorphism with neonatal RDS was stable, independent of preterm birth and Hardy-Weinberg equilibrium. In addition, the Han Chinese were more likely to be affected by SP-B C1580T polymorphisms than Caucasians and Finnish.Conclusions: Our findings suggest that SP-B C1580T polymorphism may be a protective factor against neonatal RDS.

Harnessing inhaled nanoparticles to overcome the pulmonary barrier for respiratory disease therapy

The lack of effective treatments for pulmonary diseases presents a significant global health burden, primarily due to the challenges posed by the pulmonary barrier that hinders drug delivery to the lungs. Inhaled nanomedicines, with their capacity for localized and precise drug delivery to specific pulmonary pathologies through the respiratory route, hold tremendous promise as a solution to these challenges. Nevertheless, the realization of efficient and safe pulmonary drug delivery remains fraught with multifaceted challenges. This review summarizes the delivery barriers associated with major pulmonary diseases, the physicochemical properties and drug formulations affecting these barriers, and emphasizes the design advantages and functional integration of nanomedicine in overcoming pulmonary barriers for efficient and safe local drug delivery. The review also deliberates on established nanocarriers and explores drug formulation strategies rooted in these nanocarriers, thereby furnishing essential guidance for the rational design and implementation of pulmonary nanotherapeutics. Finally, this review cast a forward-looking perspective, contemplating the clinical prospects and challenges inherent in the application of inhaled nanomedicines for respiratory diseases.

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.

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..

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.

Health Economic Studies of Surfactant Replacement Therapy in Neonates with Respiratory Distress Syndrome: A Systematic Literature Review

BACKGROUND

Neonatal respiratory distress syndrome (RDS) is one of the most common problems for preterm infants, and symptoms include tachypnoea, grunting, retractions and cyanosis, which occur immediately after birth. Treatment with surfactants has reduced morbidity and mortality rates associated with neonatal RDS.

OBJECTIVE

The objective of this review is to describe the treatment costs, healthcare resource utilization (HCRU) and economic evaluations of surfactant use in the treatment of neonates with RDS.

METHODS

A systematic literature review (SLR) was performed to identify available economic evaluations and costs associated with neonatal RDS. Electronic searches were conducted in Embase, MEDLINE, MEDLINE In-Process, NHS EED, DARE and HTAD to identify studies published between 2011 and 2021. Supplementary searches of reference lists, conference proceedings, websites of global health technology assessment bodies and other relevant sources were conducted. Publications were screened by two independent reviewers for inclusion and followed the population, interventions, comparators and outcomes framework eligibility criteria. Quality assessment of the identified studies was performed.

RESULTS

Eight publications included in this SLR met all eligibility criteria: three conference abstracts and five peer-reviewed original research articles. Four of these publications evaluated costs/HCRU, and five (three abstracts and two peer-reviewed articles) investigated economic evaluations (two from Russia, and one each from Italy, Spain and England). The main cost drivers and causes of increased HCRU were invasive ventilation, duration of hospitalization and RDS-associated complications. There were no significant differences in neonatal intensive care unit (NICU) length of stay or NICU total costs between infants treated with beractant (Survanta^®), calfactant (Infasurf^®) or poractant alfa (Curosurf^®). However, treatment with poractant alfa was associated with reduced total costs compared with no treatment, continuous positive airway pressure (CPAP) alone or calsurf (Kelisu^®), due to shorter duration of hospitalization and fewer complications. Early use of the surfactant after birth was more clinically effective and cost-effective than late intervention in infants with RDS. Poractant alfa was found to be cost-effective and cost-saving compared to beractant for the treatment of neonatal RDS in two Russian studies.

CONCLUSION

There were no significant differences in NICU length of stay or NICU total costs between surfactants evaluated for treating neonates with RDS. However, early use of surfactant was found to be more clinically effective and cost-effective than late treatment. Treatment with poractant alfa was found to be cost-effective versus beractant and cost-saving compared with CPAP alone or beractant or CPAP in combination with calsurf. Limitations included the small number of studies, the geographic scope of the studies and the retrospective study design of the cost-effectiveness studies.

Meta-Analysis of Hippocampal Volume and Episodic Memory in Preterm and Term Born Individuals

Preterm birth (< 37 weeks gestation) has been associated with memory deficits, which has prompted investigation of possible alterations in hippocampal volume in this population. However, existing literature reports varying effects of premature birth on hippocampal volume. Specifically, it is unclear whether smaller hippocampal volume in preterm-born individuals is merely reflective of smaller total brain volume. Further, it is not clear if hippocampal volume is associated with episodic memory functioning in preterm-born individuals. Meta-analysis was used to investigate the effects of premature birth on hippocampal volume and episodic memory from early development to young adulthood (birth to 26). PubMed, PsychINFO, and Web of Science were searched for English peer-reviewed articles that included hippocampal volume of preterm and term-born individuals. Thirty articles met the inclusion criteria. Separate meta-analyses were used to evaluate standardized mean differences between preterm and term-born individuals in uncorrected and corrected hippocampal volume, as well as verbal and visual episodic memory. Both uncorrected and corrected hippocampal volume were smaller in preterm-born compared to term-born individuals. Although preterm-born individuals had lower episodic memory performance than term-born individuals, the limited number of studies only permitted a qualitative review of the association between episodic memory performance and hippocampal volume. Tested moderators included mean age, pre/post-surfactant era, birth weight, gestational age, demarcation method, magnet strength, and slice thickness. With this meta-analysis, we provide novel evidence of the effects of premature birth on hippocampal volume.

Surfactin-like lipopeptides from Bacillus clausii efficiently bind to spike glycoprotein of SARS-CoV-2

The coronavirus disease 2019 (COVID-19) rapidly spread across the globe, infecting millions and causing hundreds of deaths. It has been now around three years but still, it remained a serious threat worldwide, even after the availability of some vaccines. Bio-surfactants are known to have antiviral activities and might be a potential alternative for the treatment of SARS-CoV-2 infection. In the present study, we have isolated and purified, a surfactin-like lipopeptide produced by a probiotic bacterial strain Bacillus clausii TS. Upon purification and characterization with MALDI analysis, the molecular weight of the lipopeptide is confirmed as 1037 Da (similar to surfactin C) which is known to have antiviral activities against various enveloped viruses. Purified surfactin-like lipopeptide showed efficient binding and inhibition of SARS-CoV-2 spike (S1) protein, revealed by competitive ELISA assay. Further, we have explored the complete thermodynamics of the inhibitory binding of surfactin-like lipopeptide with S1 protein using isothermal titration calorimetric (ITC) assay. ITC results are in agreement with ELISA with a binding constant of 1.78 × 10-4 M-1. For further validation of the inhibitory binding of surfactin-like lipopeptide with S1 protein and its receptor binding domain (RBD), we performed molecular docking, dynamics, and simulation experiments. Our results suggested that surfactin could be a promising drug agent for the spike protein targeting drug development strategy against SARS-CoV-2 and other emerging variants.Communicated by Ramaswamy H. Sarma.

Nasal intermittent positive pressure ventilation as a rescue therapy after nasal continuous positive airway pressure failure in infants with respiratory distress syndrome

OBJECTIVE

Evaluate whether nasal intermittent positive-pressure ventilation (NIPPV) as rescue therapy after initial nasal continuous positive airway (NCPAP) failure reduces need for invasive mechanical ventilation (IMV) in infants with respiratory distress syndrome (RDS).

DESIGN

Retrospective cohort involving 156 preterm infants who failed initial NCPAP and were then submitted to NIPPV rescue therapy and classified into NIPPV success or failure, according to need for IMV.

RESULT

Of all infants included, 85 (54.5%) were successfully rescued with NIPPV while 71 (45.5%) failed. The NIPPV success group had significantly lower rates of bronchopulmonary dysplasia, peri/intraventricular hemorrhage, patent ductus arteriosus and greater survival without morbidities (all p ≤ 0.01). Infants who failed NIPPV had earlier initial NCPAP failure (p = 0.09). In final logistic regression model, birthweight ≤1000 g and need for surfactant remained significant factors for NIPPV failure.

CONCLUSION

NIPPV rescue therapy reduced the need for IMV in infants that failed NCPAP and was associated with better outcomes.

Low Serum Vascular Endothelial Growth Factor Level Predicts Adverse Outcomes in Neonates with Respiratory Distress Syndrome

Objective: Preterm neonates are susceptible to neonatal respiratory distress syndrome (NRDS). Lower levels of cord blood vascular endothelial growth factor (VEGF) are implicated in NRDS. This study aims to explore whether the serum VEGF level has prognostic values on neonates with respiratory distress syndrome (RDS). Methods: A total of 80 infants diagnosed with NRDS were enrolled, with 70 preterm neonates without NRDS as controls. Cord blood samples before treatment and venous blood samples after treatment were collected and clinical information was recorded. The serum VEGF level was measured using enzyme-linked immunosorbent assay kits. Receiver operating characteristic (ROC) curve was used to evaluate whether serum VEGF is a biomarker of NRDS. Newborns were followed up for 1 month to collect survival information. The influence of VEGF levels on overall survival was analyzed using the Kaplan-Meier method. The univariate and multivariate Cox regression models were adopted to assess the prognostic factor of NRDS. Results: VEGF level was decreased in sera of neonates with RDS. The area under the ROC curve of VEGF level in distinguishing neonates with RDS from neonates without RDS was 0.949, with a cutoff value of 39.72 (87.50% sensitivity, 87.14% specificity). Serum VEGF was a biomarker of NRDS. Neonates with RDS with high VEGF levels had longer periods of survival than those with low VEGF levels. NRDS grade and VEGF level were independent prognostic factors affecting the overall survival of neonates with RDS. Conclusion: Decreased serum VEGF level in RDS neonates can predict the poor prognosis of NRDS, and VEGF level might be an independent prognostic factor for the overall survival of RDS neonates. Clinical Trial Registration No. 201901A.

Efficacy of synthetic surfactant (CHF5633) bolus and/or lavage in meconium-induced lung injury in ventilated newborn rabbits

BACKGROUND

The pathogenesis of neonatal meconium aspiration syndrome (MAS) involves meconium-induced lung inflammation and surfactant inactivation. Bronchoalveolar lavage (BAL) with diluted surfactant facilitates the removal of meconium. CHF5633, one of the most promising synthetic surfactants, is effective in neonatal respiratory distress syndrome. Here we investigated its efficacy via BAL in an experimental MAS model.

METHODS

Experimental MAS was induced at birth in near-term newborn rabbits by intratracheal instillation of reconstituted human meconium. First, undiluted CHF5633 was compared with a porcine-derived surfactant (Poractant alfa) via intratracheal bolus (200 mg/kg). Second, the efficacy of BAL with diluted CHF5633 (5 mg/mL, 20 ml/kg) alone, or followed by undiluted boluses (100 or 300 mg/kg), was investigated.

RESULTS

Meconium instillation caused severe lung injury, reduced endogenous surfactant pool, and poor survival. CHF5633 had similar benefits in improving survival and alleviating lung injury as Poractant alfa. CHF5633 BAL plus higher boluses exerted better effects than BAL or bolus alone in lung injury alleviation by reversing phospholipid pools and mitigating proinflammatory cytokine mRNA expression, without fluid retention and function deterioration.

CONCLUSIONS

CHF5633 improved survival and alleviated meconium-induced lung injury, the same as Poractant alfa. CHF5633 BAL plus boluses was the optimal modality, which warrants further clinical investigation.

IMPACT

To explore the efficacy of a synthetic surfactant, CHF5633, in neonatal lung protection comparing with Poractant alfa in a near-term newborn rabbit model with meconium-induced lung injury. Similar effects on improving survival and alleviating lung injury were found between CHF5633 and Poractant alfa. Optimal therapeutic effects were identified from the diluted CHF5633 bronchoalveolar lavage followed by its undiluted bolus instillation compared to the lavage or bolus alone regimens. Animals with CHF5633 lavage plus bolus regimen exerted neither substantial lung fluid retention nor lung mechanics deterioration but a trend of higher pulmonary surfactant-associated phospholipid pools.

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.

Effects of prophylactic indomethacin on intraventricular hemorrhage and adverse outcomes in neonatal intensive care unit

OBJECTIVE

To identify the relationship between prophylactic indomethacin (PI) administration and incidence of intraventricular hemorrhage.

STUDY DESIGN

A retrospective analysis of extremely premature infants <27 weeks gestational age born between January 2014 and September 2020.

RESULTS

A total of 421 infants were included from three of Nationwide Children's Hospital delivery centers. Of those 255 (61%) received PI. After adjustment by inverse proportionality treatment weighting (IPTW), no differences were found in incidence of intraventricular hemorrhage (IVH) at the time of the first ultrasound, 31% vs. 33% in PI and control groups respectively (p = 0.68). The rate of rise of serum creatinine from baseline to day of life four was significantly higher in the PI group (0.14 mg/dl PI and 0.03 mg/dl control, p < 0.001).

CONCLUSION

PI was not associated with any benefit in prevention of IVH, but is associated with adverse effects including acute rise in creatinine.

Comparative effectiveness of calfactant and beractant in neonatal respiratory distress syndrome: A systemic review and meta-analysis

INTRODUCTION

Animal derived surfactants are considered to be the standard treatment for neonatal respiratory distress syndrome (NRDS). However, their comparative effectiveness remains inconclusive given the multiple prior studies with inconsistent results. Therefore, we conducted a systematic review and meta analysis to compare the effectiveness of two animal extract surfactants (calfactant and beractant) for the management of NRDS.

METHODS

We searched Pubmed, Scopus, and Google Scholar for studies comparing efficacy of calfactant and beractant for the treatment of NRDS. Mean differences (MD) and risk ratios (RR) with a 95% confidence interval (CI) were calculated using Review Manager.

RESULT

We found no significant difference between calfactnat and beractant groups in the primary outcomes: neonatal mortality before the age of 28 days (RR = 1.19, 95% CI = 0.97-1.46, p = 0.09), mortality before the hospital release (RR = 1.12, 95% Cl = 0.94-1.33, p = 0.22), oxygen requirement at 28 days of age (RR = 0.97, 95% CI = 0.90-1.05, p = 0.52), and death or oxygen need at 36 weeks postmenstrual age (RR = 0.99, 95% CI = 0.91-1.08, p = 0.81). The duration of supplementary oxygen was significantly lower in calfactant users (MD = -4.95, 95% CI = -7.60--2.30, p = 0.0002). Calfactant significantly lowered the duration of hospital stay, risk of pneumothorax and air leak syndrome whereas beractant users had lower risk of intraventricular hemorrhage (Grades 3 and 4).

CONCLUSION

There is no substantial difference in the efficacy of both surfactants in the prophylaxis and treatment of NRDS.

Natural Versus Synthetic Surfactant Therapy in Respiratory Distress Syndrome of Prematurity

OBJECTIVES

To compare the clinical efficacy and the cost of treatment between the newborns who received either a natural or a protein-free synthetic surfactant for respiratory distress syndrome (RDS) of prematurity.

METHODS

This is a retrospective analytical study incorporating comparisons of clinical parameters and cost in newborns having RDS of prematurity who received either Survanta (bovine lung extract), a natural surfactant or Surfact (protein-free colfosceril palmitate), a synthetic surfactant.

RESULTS

There were 100 newborns who received either of the natural (n = 52) or synthetic (n = 48) surfactant with mean (SD) gestational age and mean (SD) birth weight of 31.5 (2.6) wk, 1425 (461) g and 32.2 (2.2) wk, 1519 (413) g, respectively. Majority of the newborns (> 90%) received endotracheal surfactant within the first 24 h of life and had similar baseline characteristics in either group. No differences were noted in ventilator settings on admission and 24 h after surfactant/admission. Oxygen requirement, extubation age, complications, hospital stay, and mortality were similar across groups, except that the necrotizing enterocolitis was noted only in natural surfactant group. There was a significant pharmacy cost savings in synthetic surfactant group.

CONCLUSION

Synthetic surfactant was comparable to natural surfactant with regard to outcomes, like ventilator settings, hospital stay, and mortality. Pharmacy cost was less in synthetic surfactant group.

Prioritizing Health Care Strategies to Reduce Childhood Mortality

IMPORTANCE

Although child mortality trends have decreased worldwide, deaths among children younger than 5 years of age remain high and disproportionately circumscribed to sub-Saharan Africa and Southern Asia. Tailored and innovative approaches are needed to increase access, coverage, and quality of child health care services to reduce mortality, but an understanding of health system deficiencies that may have the greatest impact on mortality among children younger than 5 years is lacking.

OBJECTIVE

To investigate which health care and public health improvements could have prevented the most stillbirths and deaths in children younger than 5 years using data from the Child Health and Mortality Prevention Surveillance (CHAMPS) network.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study used longitudinal, population-based, and mortality surveillance data collected by CHAMPS to understand preventable causes of death. Overall, 3390 eligible deaths across all 7 CHAMPS sites (Bangladesh, Ethiopia, Kenya, Mali, Mozambique, Sierra Leone, and South Africa) between December 9, 2016, and December 31, 2021 (1190 stillbirths, 1340 neonatal deaths, 860 infant and child deaths), were included. Deaths were investigated using minimally invasive tissue sampling (MITS), a postmortem approach using biopsy needles for sampling key organs and fluids.

MAIN OUTCOMES AND MEASURES

For each death, an expert multidisciplinary panel reviewed case data to determine the plausible pathway and causes of death. If the death was deemed preventable, the panel identified which of 10 predetermined health system gaps could have prevented the death. The health system improvements that could have prevented the most deaths were evaluated for each age group: stillbirths, neonatal deaths (aged <28 days), and infant and child deaths (aged 1 month to <5 years).

RESULTS

Of 3390 deaths, 1505 (44.4%) were female and 1880 (55.5%) were male; sex was not recorded for 5 deaths. Of all deaths, 3045 (89.8%) occurred in a healthcare facility and 344 (11.9%) in the community. Overall, 2607 (76.9%) were deemed potentially preventable: 883 of 1190 stillbirths (74.2%), 1010 of 1340 neonatal deaths (75.4%), and 714 of 860 infant and child deaths (83.0%). Recommended measures to prevent deaths were improvements in antenatal and obstetric care (recommended for 588 of 1190 stillbirths [49.4%], 496 of 1340 neonatal deaths [37.0%]), clinical management and quality of care (stillbirths, 280 [23.5%]; neonates, 498 [37.2%]; infants and children, 393 of 860 [45.7%]), health-seeking behavior (infants and children, 237 [27.6%]), and health education (infants and children, 262 [30.5%]).

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, interventions prioritizing antenatal, intrapartum, and postnatal care could have prevented the most deaths among children younger than 5 years because 75% of deaths among children younger than 5 were stillbirths and neonatal deaths. Measures to reduce mortality in this population should prioritize improving existing systems, such as better access to antenatal care, implementation of standardized clinical protocols, and public education campaigns.

Laryngeal Mask Airway for Surfactant Administration Versus Standard Treatment Methods in Preterm Neonates with Respiratory Distress Syndrome: A Systematic Review and Meta-analysis

OBJECTIVE

Laryngeal mask airway (LMA) has emerged as an alternative surfactant delivery method. The effectiveness of this method for the delivery of surfactant is uncertain. A meta-analysis of randomized control trials (RCTs) comparing LMA with standard methods of surfactant delivery for the outcomes of surfactant dose repetition, oxygen requirement, mechanical ventilation, intubation, mortality, bronchopulmonary dysplasia (BPD), and pneumothorax.

STUDY DESIGN

Systematic review and meta-analysis of RCTs. Homogeneity between studies was analyzed by using I² statistics. Risk ratio or mean difference of outcomes was assessed from random effects models. Subgroup analyses were conducted when necessary. Data sources are as follows: Ovid Medline, Embase, and the Cochrane Central Register of Controlled trials from inception till December 2018, bibliographies of identified reviews and trial registries for ongoing studies. RCTs comparing short-term respiratory outcomes in neonates with respiratory distress syndrome who were administered surfactant through an LMA versus standard method of care.

RESULTS

Six RCTs were identified, enrolling a total of 357 infants. Administering surfactant via LMA was associated with decreased FiO₂ requirement (mean difference = 1.82 (95% confidence interval [CI]: -6.01-9.66), decreased intubation (risk ratio [RR] = 0.17; 95% CI: 0.05-0.57), and decreased mechanical ventilation (RR = 0.44; 95% CI: 0.31-0.61). There were no significant differences between groups for death, BPD, or pneumothorax.

CONCLUSION

LMA might be an effective alternative method of surfactant delivery; however, further high-quality RCTs with larger sample size and including extreme preterm infants are needed to establish LMA as an alternative technique for surfactant delivery.

KEY POINTS

· Pulmonary surfactants reduce mortality and pulmonary air leaks in newborns with respiratory distress syndrome.. · Preterm lungs are at risk of volutrauma by mechanical ventilation; laryngoscopy is still traumatic.. · Surfactant administration via LMA to avoid mechanical ventilation and intubation might be feasible..

The effect of high-frequency oscillatory ventilator combined with pulmonary surfactant in the treatment of neonatal respiratory distress syndrome

OBJECTIVE

To investigate the efficacy of high-frequency oscillatory ventilation (HFOV) combined with pulmonary surfactant (PS) in the treatment of neonatal respiratory distress syndrome (NRDS).

METHODS

This study is a retrospective clinical study. Seventy-two NRDS neonates were selected as the subjects from November 2019 to November 2020, and divided into observation group (40 cases, HFOV treatment) and control group (32 cases, conventional mechanical ventilation treatment). All cases were treated with PS and comprehensive treatment. The therapeutic effect, arterial partial pressure of oxygen (PaO2), arterial partial pressure of carbon dioxide (PaCO2), Percentage of inhaled oxygen concentration (FiO2), mean arterialpressure, oxygenation index (OI), and complications were compared in the 2 groups.

RESULTS

The total effective rate of the observation group was 90.0%, significantly higher than that of the control group. After treatment, the observation group has higher PaO2 levels and lower levels of PaCO2, mean arterial pressure, FiO2, and OI than the control group. There was no significant difference in the incidence of complications between the 2 groups.

CONCLUSION

HFOV combined with PS has a significant effect on NRDS, which can improve the arterial blood gas index without increasing the incidence of complications.

Ruminant conceptus-maternal interactions: interferon-tau and beyond

Embryonic or fetal loss in cattle is associated with problems that occur during oocyte maturation, early embryonic development, conceptus elongation, maternal recognition of pregnancy (MRP), and/or placental attachment and implantation. Many of these problems manifest as inadequate or asynchronous communication between the developing conceptus and endometrium, resulting in pregnancy failure. This review will provide an overview of how various conceptus-endometrial paracrine signaling systems control the fate of early pregnancy in cattle and other ruminants. We begin by summarizing the actions of interferon-tau, the classic MRP signal in ruminates, and then explore how other secretory factors derived from either the conceptus or endometrium influence establishment and maintenance of pregnancy. Insight into how the endometrium responds to male vs. female conceptuses or conceptuses produced by in vitro methods will also be described. Specific focus will be placed on describing how "omic" technologies and other cutting-edge techniques have assisted with identifying novel conceptus and/or endometrial factors and their functions. Recent findings indicate that the endometrial transcriptome and histotroph are altered by conceptus sex, quality, and origin, suggesting that the endometrium is a sensor of conceptus biochemistry. Although the endometrium has a certain level of flexibility in terms of conceptus-maternal interactions, this interplay is not sufficient to retain some pregnancies. However, new information inspires us to learn more and will help develop technologies that mitigate early embryonic loss and reproductive failure in ruminants and other animals.

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.

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.

Poractant alfa versus bovine lipid extract surfactant: prospective comparative effectiveness study

OBJECTIVE

To compare short term respiratory outcomes in preterm infants treated with bovine lipid extract surfactant or poractant alfa.

STUDY DESIGN

Prospective comparative effectiveness cohort study of infants <32 weeks' gestational age requiring surfactant in thirteen centers. Each center provided bovine lipid extract surfactant for a set period of time in the year 2019 and then changed to poractant alfa for the remainder of the year. The primary outcome was total duration of respiratory support.

RESULT

968 infants were included. 494 received bovine lipid extract surfactant and 474 received poractant alfa. No difference was observed in the total duration of respiratory support (mechanical ventilation or non-invasive) (median 38 vs 40.5 days), need to re-dose surfactant, bronchopulmonary dysplasia, survival to discharge, or length of admission.

CONCLUSION

In this pragmatic study, we did not identify any difference in short term outcomes between the groups based on the type of surfactant received.

Ultrasound Lung Image under Artificial Intelligence Algorithm in Diagnosis of Neonatal Respiratory Distress Syndrome

In order to analyze the application of ultrasonic lung imaging diagnosis model based on artificial intelligence algorithm in neonatal respiratory distress syndrome (NRDS), an ultrasonic lung imaging diagnosis model based on a deep residual network (DRN) was proposed. In this study, 90 premature infants in the hospital were selected as the research object and divided into the experimental group (45 cases) and control group (45 cases) according to whether or not they have NRDS. DRN was compared with the deep residual network (DRWSR) based on wavelet domain, deep residual network detection with normalization framework (Fisher-DRN), and distorted image edge detection preprocessor (DIEDP). Then, it was applied to the diagnosis of NRDS. The clinical data and ultrasound imaging results of infants with NRDS and ordinary premature infants were compared. The results showed that the gestational age, birth weight, and Apgar scores of the NRDS group were remarkably lower than those of ordinary children (P < 0.05). In addition, the segmentation accuracy, image feature extraction accuracy, algorithm convergence, and time loss of the DRN algorithm were better than the other three algorithms, and the differences were considerable (P < 0.05). In children with NRDS, the positive rate of abnormal pleural line, disappearance of A line, appearance of B line, and alveolar interstitial syndrome (AIS) test in the results of lung ultrasound examination in children with NRDS were all 100%. The lung consolidation became 70.8%, and the white lung-like change was 50.1%, both of which were higher than those of ordinary preterm infants, and the differences were considerable (P < 0.05). The diagnostic model of this study predicted that the AUC area of grade 1-2, grade 2-3, and grade 3-4 NRDS were 0.962, 0.881, and 0.902, respectively. To sum up, the ultrasound lung imaging diagnosis model based on the DRN algorithm had good diagnostic performance in children with NRDS and can provide useful information for clinical NRDS diagnosis and treatment.

Incidence, Predictors and Outcomes of Noninvasive Ventilation Failure in Very Preterm Infants

Non-invasive ventilation (NIV) is now considered the first-line treatment for respiratory distress syndrome in preterm infants. We aimed to evaluate the rates of non-invasive ventilation failure rate in very preterm infants, as well as to identify its predictors and associated outcomes. We designed a single-center retrospective cohort study including infants ≤32 weeks gestational age and ≤1500 g. The NIV failure was defined as the need for intubation at <72 h of life. After applying inclusion and exclusion criteria, 154 patients were included in the study, with a mean GA of 29.7 ± two weeks. The NIV failure rate was 16.2% (n = 25) and it was associated with lower bronchopulmonary dysplasia (BPD)-free survival (OR 0.08; 95% CI 0.02−0.32) and higher incidence of intraventricular hemorrhage > II (OR 6.22; 95% CI 1.36−28.3). These infants were significantly smaller in GA and weight. Higher FiO2 during resuscitation (OR 1.14; 95% CI 1.06−1.22) and after surfactant administration (OR 1.17; 95% CI 1.05−1.31) represented independent risk factors for NIV failure. In conclusion, NIV failure is frequent and it could be predicted by a higher oxygen requirement during resuscitation and a modest response to surfactant therapy. Importantly, this NIV failure is associated with worse clinical outcomes.

The Blind Spot of Pharmacology: A Scoping Review of Drug Metabolism in Prematurely Born Children

The limit for possible survival after extremely preterm birth has steadily improved and consequently, more premature neonates with increasingly lower gestational age at birth now require care. This specialized care often include intensive pharmacological treatment, yet there is currently insufficient knowledge of gestational age dependent differences in drug metabolism. This potentially puts the preterm neonates at risk of receiving sub-optimal drug doses with a subsequent increased risk of adverse or insufficient drug effects, and often pediatricians are forced to prescribe medication as off-label or even off-science. In this review, we present some of the particularities of drug disposition and metabolism in preterm neonates. We highlight the challenges in pharmacometrics studies on hepatic drug metabolism in preterm and particularly extremely (less than 28 weeks of gestation) preterm neonates by conducting a scoping review of published literature. We find that >40% of included studies failed to report a clear distinction between term and preterm children in the presentation of results making direct interpretation for preterm neonates difficult. We present summarized findings of pharmacokinetic studies done on the major CYP sub-systems, but formal meta analyses were not possible due the overall heterogeneous approaches to measuring the phase I and II pathways metabolism in preterm neonates, often with use of opportunistic sampling. We find this to be a testament to the practical and ethical challenges in measuring pharmacokinetic activity in preterm neonates. The future calls for optimized designs in pharmacometrics studies, including PK/PD modeling-methods and other sample reducing techniques. Future studies should also preferably be a collaboration between neonatologists and clinical pharmacologists.

Inhaled Medicines: Past, Present, and Future

The purpose of this review is to summarize essential pharmacological, pharmaceutical, and clinical aspects in the field of orally inhaled therapies that may help scientists seeking to develop new products. After general comments on the rationale for inhaled therapies for respiratory disease, the focus is on products approved approximately over the last half a century. The organization of these sections reflects the key pharmacological categories. Products for asthma and chronic obstructive pulmonary disease include β -2 receptor agonists, muscarinic acetylcholine receptor antagonists, glucocorticosteroids, and cromones as well as their combinations. The antiviral and antibacterial inhaled products to treat respiratory tract infections are then presented. Two "mucoactive" products-dornase α and mannitol, which are both approved for patients with cystic fibrosis-are reviewed. These are followed by sections on inhaled prostacyclins for pulmonary arterial hypertension and the challenging field of aerosol surfactant inhalation delivery, especially for prematurely born infants on ventilation support. The approved products for systemic delivery via the lungs for diseases of the central nervous system and insulin for diabetes are also discussed. New technologies for drug delivery by inhalation are analyzed, with the emphasis on those that would likely yield significant improvements over the technologies in current use or would expand the range of drugs and diseases treatable by this route of administration. SIGNIFICANCE STATEMENT: This review of the key aspects of approved orally inhaled drug products for a variety of respiratory diseases and for systemic administration should be helpful in making judicious decisions about the development of new or improved inhaled drugs. These aspects include the choices of the active ingredients, formulations, delivery systems suitable for the target patient populations, and, to some extent, meaningful safety and efficacy endpoints in clinical trials.

Developmental defects of enamel in children born preterm

INTRODUCTION

To investigate manifestations of developmental defects of enamel (DDE) in children born preterm (PT), and to explore possible neonatal morbidities related to DDE manifestation and severity.

METHODS

A cohort study of 52 children born before gestational week 32 and treated in the neonatal intensive care unit; and 55 children born at full term (FT) as a control group. All the children had a dental examination at age 1-4 years by a professional pediatric dentist. DDE was defined as an alteration in the enamel surface.

RESULTS

DDE were observed in 23 (44%) and 6 (11%) children, in the PT and FT groups, respectively, odds ratio (OR) = 6.47. The OR for damaged anterior teeth was 12.87 times higher in the PT group. DDE of molars was diagnosed in 19% and 11% of the respective groups. In the PT group, the OR of DDE was 4.1 higher among those with than without respiratory distress. The risk for DDE was 5.7 higher in those who received surfactant than in those who did not. Ventilation length, both invasive and non-invasive, was significantly related to DEE.

CONCLUSIONS

DDE was higher in children born PT than FT. The DDE rate was lower than expected based on current literature, and considering the overall increase in survival; this suggests improvement in treatments affecting DEE. Respiratory distress syndrome, surfactant administration reflecting the need for intubation, longer ventilation and local oral trauma were risk factors for DDE. We recommend routine dental examinations in follow up of children born PT, particularly those exposed to assisted ventilation.

Surfactant Therapy for Respiratory Distress Syndrome in High- and Ultra-High-Altitude Settings

OBJECTIVE

The objective of this study is to investigate the therapeutic effect of surfactant replacement therapy (SRT) on respiratory distress syndrome (RDS) in premature infants in the Qinghai-Tibet Plateau.

MATERIALS AND METHODS

This multi-center retrospective cohort study collected and screened reasonable clinical data of 337 premature infants with RDS from 10 hospitals in the Qinghai-Tibet Plateau from 2015 to 2017. We grouped the cases by rationally analyzing their baseline characteristics, using logistic analysis to evaluate each factor's effect on the prognosis of the infants, and comparing the short-term improvement in blood gas and mortality after SRT treatment at different altitudes, in high-altitude (1,500-3,500 m) and ultra-high-altitude (3,500-5,500 m) groups.

RESULTS

Independent of altitude, the mortality rate of children with RDS in the SRT group was significantly lower than that of children in the non-SRT group (both P < 0.05). The effect of SRT on preterm infants with RDS in the high-altitude group [odds ratio (OR) = 0.44, 95% confidence interval (CI) = 0.22-0.87, P = 0.02] was better than that in the infants in the ultra-high-altitude group (OR = 0.26, 95% CI = 0.13-0.58, P < 0.01), with death rates of 34.34 and 49.71%, respectively. Similarly, after SRT, the improvement of PaO₂/FiO₂ and pH of children at high altitude was significantly better than those of children at ultra-high altitude (all P < 0.01).

CONCLUSIONS

SRT plays a prominent role in curing infants with RDS in both high- and ultra-high-altitude regions, although with better effects at high rather than ultra-high altitude. This study provides a basis for further large-scale studies on SRT for RDS treatment at high altitudes.

Treatment of Respiratory Distress Syndrome with Single Recombinant Polypeptides that Combine Features of SP-B and SP-C

Treatment of respiratory distress syndrome (RDS) with surfactant replacement therapy in prematurely born infants was introduced more than 30 years ago; however, the surfactant preparations currently in clinical use are extracts from animal lungs. A synthetic surfactant that matches the currently used nature-derived surfactant preparations and can be produced in a cost-efficient manner would enable worldwide treatment of neonatal RDS and could also be tested against lung diseases in adults. The major challenge in developing fully functional synthetic surfactant preparations is to recapitulate the properties of the hydrophobic lung surfactant proteins B (SP-B) and SP-C. Here, we have designed single polypeptides that combine properties of SP-B and SP-C and produced them recombinantly using a novel solubility tag based on spider silk production. These Combo peptides mixed with phospholipids are as efficient as nature-derived surfactant preparations against neonatal RDS in premature rabbit fetuses.

A Neonate With Vertical Transmission of COVID-19 and Acute Respiratory Failure: A Case Report

BACKGROUND

This case describes a case of vertical transmission of COVID-19 from a mother to her neonate. The neonate subsequently developed acute respiratory failure consistent with adult symptoms of COVID-19.

CLINICAL FINDINGS

This preterm neonate was born at 33 4/7 weeks' gestational age to a COVID-19-positive mother and admitted to the neonatal intensive care unit (NICU) for prematurity and respiratory distress. The neonate developed acute respiratory failure with severe persistent pulmonary hypertension of newborn (PPHN) and required intubation and maximum respiratory and cardiovascular support. The neonate subsequently tested positive for COVID-19 at 24 hours of life.

PRIMARY DIAGNOSIS

Acute respiratory failure related to COVID-19 infection.

INTERVENTIONS

The neonate was admitted to the NICU on CPAP. At 11 hours of life, the neonate began to exhibit signs of worsening respiratory distress requiring intubation, mechanical, and high frequency ventilation. An echocardiogram revealed severe PPHN. The neonate required dopamine to manage hypotension and was treated with steroids to decrease inflammation associated with airway edema noted during intubation. Pharmaceutically induced paralysis, analgesia, and sedation was used to manage persistent hypoxia.

OUTCOMES

The neonate fully recovered from acute respiratory failure and was discharged home with the mother.

PRACTICE RECOMMENDATIONS

Newborns born to mothers who are positive for COVID-19 are at risk for vertical transmission of COVID-19 and should be monitored closely for acute respiratory failure. Respiratory medical management should include supportive care. Staff should also encourage parents to consider receiving the COVID-19 vaccine to protect their newborn from the possibility of developing acute respiratory failure.

Bronchopulmonary dysplasia-A historical perspective

Bronchopulmonary dysplasia (BPD) was first described by Northway et al in 1967. This article describes the evolution of our understanding of the pathophysiology of BPD and the approaches to treatments of this illness developed over the past fifty years. These interventions had their roots in the understanding of the principles of the surface tension present at air-liquid interfaces, which were developed over 150 years before BPD's initial description. Improving outcomes in neonatal care have led to greater survival of preterm and very preterm infants, and to an evolution of the pathogenesis and pathology of BPD, from an illness caused primarily by barotrauma and oxygen toxicity to one of interruption of lung development. While the incidence of BPD has remained about the same in recent decades, this is because survival of infants born at lower gestational ages is increasing. Understanding of molecular, genetic and physiologic mechanisms has led to newer treatments that have mitigated some of the harmful effects of prolonged mechanical ventilation. Recognition of BPD as a chronic multi-system disease has resulted in further improvements in care after discharge from neonatal intensive care. Since many of the origins of chronic obstructive lung disease in adults are based in childhood respiratory illnesses, improving outcomes of BPD in infancy and childhood will undoubtedly lead to improved respiratory outcomes in the adults that these children will become.

Surfactant delivery via thin catheters: Methods, limitations, and outcomes

Various less invasive surfactant administration strategies like surfactant replacement therapy via thin catheters, laryngeal mask airway, pharyngeal instillation, and nebulized surfactant are increasingly being practiced to avoid the harmful effects of endotracheal intubation and ventilation. Numerous studies have been done to study surfactant replacement via thin catheters whereas little data is available for other methods. However, there are variations in premedication policies, type of respiratory support used in these studies. Surfactant delivery using thin catheters has been reported to be associated with decrease in the need for mechanical ventilation (MV), duration of MV, bronchopulmonary dysplasia and neonatal mortality. With the current evidence, among all the available surfactant delivery methods, the one using thin catheters appears to be the most feasible and beneficial to improve clinical neonatal outcomes.

Nanoparticle-mediated surfactant therapy in patients with severe COVID-19: a perspective

Coronavirus disease 2019 (COVID-19) is an RNA virus-based disease that can be deadly. For critically ill patients, mechanical ventilation is an important life-saving treatment. However, mechanical ventilation shows a trade-off between supporting respiratory function and ventilator-induced lung injury (VILI). Surfactant therapy is a medical administration of exogenous surfactant to supplement or replace deficient or dysfunctional endogenous surfactant. Surfactant therapy can be used to postpone or shorten the use of mechanical ventilation to minimize or avoid VILI, because surfactants can reduce surface tension, improve lung compliance, and enhance oxygenation. In addition, nanotechnology can be applied to improve the therapeutic effect and reduce the adverse effects of surfactants. In this perspective, we discussed how nanoparticles deliver surfactants through intravenous injection and inhalation to the expected lung disease regions where surfactants are mostly needed, and discussed the prospects of nanoparticle-mediated surfactant therapy in the treatment of patients with severe COVID-19.

Efficacy and safety of surfactant administration via thin catheter in preterm infants with neonatal respiratory distress syndrome: A systematic review and meta-analysis

OBJECTIVE

The efficacy and safety of surfactant administration via thin catheter in preterm infants with neonatal respiratory distress syndrome (NRDS) was investigated.

METHODS

PubMed, Embase, Cochrane Library, and Web of Science databases were searched to identify randomized controlled trials (RCTs) that comparing thin catheter technique with intubation for surfactant delivery in preterm infants with NRDS.

RESULTS

Thirteen RCTs (1931 infants) were included in the meta-analysis. The use of thin catheter technique decreased the incidences of bronchopulmonary dysplasia (BPD), pneumothorax, and hemodynamically significant patent ductus arteriosus (hsPDA) (risk ratio [RR]: 0.59, 95% confidence interval [CI]: 0.46-0.75, p < .0001; RR: 0.60, 95% CI: 0.39-0.93, p = .02 and RR: 0.88, 95% CI: 0.78-1.00, p = .04, respectively). In addition, infants in the intervention group required less mechanical ventilation within 72 h of life or during hospitalization (RR: 0.60, 95% CI: 0.48-0.75, p < .00001 and RR: 0.64, 95% CI: 0.49-0.82, p = .0005, respectively) compared with infants in the control group. However, the rate of surfactant reflux was higher in the intervention group than that in the control group (RR: 2.12, 95% CI: 1.37-3.29, p = .0008). There were no significant differences in mortality and other outcomes between the two groups.

CONCLUSION

The administration of surfactant via thin catheter could lower the requirement for mechanical ventilation, and decrease the incidence of BPD, pneumothorax, and hsPDA.

Physiological fluid interfaces: Functional microenvironments, drug delivery targets, and first line of defense

Fluid interfaces, i.e. the boundary layer of two liquids or a liquid and a gas, play a vital role in physiological processes as diverse as visual perception, oral health and taste, lipid metabolism, and pulmonary breathing. These fluid interfaces exhibit a complex composition, structure, and rheology tailored to their individual physiological functions. Advances in interfacial thin film techniques have facilitated the analysis of such complex interfaces under physiologically relevant conditions. This allowed new insights on the origin of their physiological functionality, how deviations may cause disease, and has revealed new therapy strategies. Furthermore, the interactions of physiological fluid interfaces with exogenous substances is crucial for understanding certain disorders and exploiting drug delivery routes to or across fluid interfaces. Here, we provide an overview on fluid interfaces with physiological relevance, namely tear films, interfacial aspects of saliva, lipid droplet digestion and storage in the cell, and the functioning of lung surfactant. We elucidate their structure-function relationship, discuss diseases associated with interfacial composition, and describe therapies and drug delivery approaches targeted at fluid interfaces. STATEMENT OF SIGNIFICANCE: Fluid interfaces are inherent to all living organisms and play a vital role in various physiological processes. Examples are the eye tear film, saliva, lipid digestion & storage in cells, and pulmonary breathing. These fluid interfaces exhibit complex interfacial compositions and structures to meet their specific physiological function. We provide an overview on physiological fluid interfaces with a focus on interfacial phenomena. We elucidate their structure-function relationship, discuss diseases associated with interfacial composition, and describe novel therapies and drug delivery approaches targeted at fluid interfaces. This sets the scene for ocular, oral, or pulmonary surface engineering and drug delivery approaches.

Efficacy of intratracheal budesonide-surfactant combined therapy in surfactant-insufficient rat lungs with lipopolysaccharide insult

BACKGROUND

Intratracheal steroid therapy for lipopolysaccharide (LPS)-induced acute lung injury (ALI) remains challenging particularly in surfactant-insufficient lungs, a common problem of neonatal or pediatric ALI. Surfactant has been used as a vehicle for intratracheal steroid in the treatment of other types of ALI. This study investigated the efficacy of intratracheal budesonide (BUD) delivered by two concentrations of surfactant in the treatment of LPS-induced ALI in surfactant-insufficient rat lungs.

METHODS

Male adult rats were anesthetized and ventilated. Our ALI model was established by repeated saline lavage to produce surfactant insufficiency, followed by intratracheal LPS instillation. Five study groups (n = 5 for each) with different intratracheal treatments following ALI were used: control (no treatment), BUD (NS-BUD; BUD in saline), DS-BUD (BUD in diluted surfactant), FS-BUD (BUD in full-strength surfactant), FS (full-strength surfactant). Cardiopulmonary variables were monitored 4 hours post injury. Histological and immunohistochemical assessments of the lungs were performed.

RESULTS

The FS-BUD and FS groups presented better gas exchange, less metabolic acidosis, less oxygen index, and more stable hemodynamic changes than the DS-BUD, NS-BUD, and control groups. The total lung injury scores assessed by histological examination were ordered as follows: FS-BUD < DS-BUD or FS < NS-BUD < control. The immunostaining intensities of lung myeloperoxidase showed the following order: NS-BUD, DS-BUD, or FS-BUD < control or FS. Only the FS-BUD group displayed a smaller immunostaining intensity of lung tumor necrosis factor (TNF)-α than the control group.

CONCLUSION

Among our therapeutic strategies, intratracheal BUD delivered by full-strength surfactant confers an optimal protection against LPS-induced ALI in surfactant-insufficient rat lungs.

The Role of Pulmonary Surfactants in the Treatment of Acute Respiratory Distress Syndrome in COVID-19

Lung alveolar type-II (AT-II) cells produce pulmonary surfactant (PS), consisting of proteins and lipids. The lipids in PS are primarily responsible for reducing the air-fluid surface tension inside the alveoli of the lungs and to prevent atelectasis. The proteins are of two types: hydrophilic and hydrophobic. Hydrophilic surfactants are primarily responsible for opsonisation, thereby protecting the lungs from microbial and environmental contaminants. Hydrophobic surfactants are primarily responsible for respiratory function. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) enters the lungs through ACE-2 receptors on lungs and replicates in AT-II cells leading to the etiology of Coronavirus disease - 2019 (COVID-19). The SARS-CoV-2 virus damages the AT-II cells and results in decreased production of PS. The clinical symptoms of acute respiratory distress syndrome (ARDS) in COVID-19 patients are like those of neonatal respiratory distress syndrome (NRDS). The PS treatment is first-line treatment option for NRDS and found to be well tolerated in ARDS patients with inconclusive efficacy. Over the past 70°years, a lot of research is underway to produce natural/synthetic PS and developing systems for delivering PS directly to the lungs, in addition to finding the association between PS levels and respiratory illnesses. In the present COVID-19 pandemic situation, the scientific community all over the world is searching for the effective therapeutic options to improve the clinical outcomes. With a strong scientific and evidence-based background on role of PS in lung homeostasis and infection, few clinical trials were initiated to evaluate the functions of PS in COVID-19. Here, we connect the data on PS with reference to pulmonary physiology and infection with its possible therapeutic benefit in COVID-19 patients.

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.

Can first trimester pregnancy-associated plasma protein-A predict the surfactant needs of preterm neonates?

BACKGROUND

Low values of pregnancy associated plasma protein A (PAPP-A), have been shown to be associated with some poor gestational outcomes, especially those related to placental deficiency such as pre-eclampsia and fetal growth restriction as well as preterm labor. The aim of this study was to compare first trimester PAPP-A MoM values with the surfactant needs of newborns of pregnant women who had a preterm delivery.

METHODS

This study included 216 pregnant women who had a preterm delivery, who were found to be in the low-risk group based on their aneuploidy screening. The women were separated into two groups based on the surfactant receipts of their newborns. A record was made of the obstetric history, birth characteristics of the preterm infants, and whether or not there was a need for surfactant.

RESULTS

A comparison of the PAPP-A values of the two groups revealed that the group that received surfactant had statistically significantly lower PAPP-A values (t(-3.97) = 0.203, p <  0.001). When the cut-off value of PAPP-A was taken as 1 MoM and the gestational age was analyzed together with the birth weight, PAPP-A alone was found to be a significant independent variable for the prediction of respiratory distress syndrome (RDS) (p = 0.031; OR:8.2 (1.2-55.6)).

CONCLUSIONS

The result of this study demonstrated that PAPP-A MoM values may be significant in predicting the need for surfactant in RDS, which is a frequently seen condition in the neonatal period.

Development and Characterization of Excipient Enhanced Growth (EEG) Surfactant Powder Formulations for Treating Neonatal Respiratory Distress Syndrome

This study aimed to develop and characterize a spray-dried powder aerosol formulation of a commercially available surfactant formulation, Survanta® intratracheal suspension, using the excipient enhanced growth (EEG) approach. Survanta EEG powders were prepared by spray drying of the feed dispersions containing Survanta® (beractant) intratracheal suspension, hygroscopic excipients (mannitol and sodium chloride), and a dispersion enhancer (l-leucine or trileucine) in 5 or 20% v/v ethanol in water using the Buchi Nano Spray Dryer B-90 HP. Powders were characterized for primary particle size, morphology, phospholipid content, moisture content, thermal properties, moisture sorption, and surface activity. The aerosol performance of the powders was assessed using a novel low-volume dry powder inhaler (LV-DPI) device operated with 3-mL volume of dispersion air. At both ethanol concentrations, in comparison to trileucine, l-leucine significantly reduced the primary particle size and span and increased the fraction of submicrometer particles of the Survanta EEG powders. The l-leucine-containing Survanta EEG powders exhibited good aerosolization performance with ≥ 88% of the mass emitted (% nominal) after 3 actuations from the modified LV-DPI device. In addition, l-leucine-containing powders had a low moisture content (< 3% w/w) with transition temperatures close to the commercial surfactant formulation and retained their surface tension reducing activity after formulation processing. A Survanta EEG powder containing l-leucine was developed which showed efficient aerosol delivery from the modified LV-DPI device using a low dispersion air volume.

Performance of Low Air Volume Dry Powder Inhalers (LV-DPI) when Aerosolizing Excipient Enhanced Growth (EEG) Surfactant Powder Formulations

Efficient delivery of dry powder aerosols dispersed with low volumes of air is challenging. This study aims to develop an efficient dry powder inhaler (DPI) capable of delivering spray-dried Survanta-EEG powders (3-10 mg) with a low volume (3 mL) of dispersion air. A series of iterative design modifications were made to a base low air volume actuated DPI. The modifications included the replacement of the original capsule chamber with an integral dose containment chamber, alteration of the entrainment air flow path through the device (from single-sided (SS) to straight through (ST)), change in the number of air inlet holes (from one to three), varying the outlet delivery tube length (45, 55, and 90 mm) and internal diameter (0.60, 0.89, and 1.17 mm). The modified devices were evaluated by determining the influence of the modifications and powder fill mass on aerosol performance of spray-dried Survanta-EEG powders. The optimal DPI was also evaluated for its ability to aerosolize a micronized powder. The optimized dose containment unit DPI had a 0.21 mL powder chamber, ST airflow path, three-0.60 mm air inlet holes, and 90 mm outlet delivery tube with 0.89 mm internal diameter. The powder dispersion characteristics of the optimal device were independent of fill mass with good powder emptying in one 3 mL actuation. At 10 mg fill mass, this device had an emitted mass of 5.3 mg with an aerosol Dv50 of 2.7 μm. After three 3 mL actuations, >85% of the spray-dried powder was emitted from the device. The emitted mass of the optimal device with micronized albuterol sulfate was >72% of the nominal fill mass of 10 mg in one 3 mL actuation. Design optimization produced a DPI capable of efficient performance with a dispersion air volume of 3 mL to aerosolize Survanta-EEG powders.

Lower insulin sensitivity remains a feature of children born very preterm

BACKGROUND

The first report of children born very preterm (<32 weeks of gestation) having insulin resistance was made 16 years ago. However, neonatal care has improved since. Thus, we aimed to assess whether children born very preterm still have lower insulin sensitivity than term controls.

METHODS

Participants were prepubertal children aged 5 to 11 years born very preterm (<32 weeks of gestation; n = 51; 61% boys) or at term (37-41 weeks; n = 50; 62% boys). Frequently sampled intravenous glucose tolerance tests were performed, and insulin sensitivity was calculated using Bergman's minimal model. Additional clinical assessments included anthropometry, body composition using whole-body dual-energy X-ray absorptiometry scans, clinic blood pressure, and 24-hour ambulatory blood pressure monitoring.

RESULTS

Children born very preterm were 0.69 standard deviation score (SDS) lighter (P < .001), 0.53 SDS shorter (P = .003), and had body mass index 0.57 SDS lower (P = .003) than children born at term. Notably, children born very preterm had insulin sensitivity that was 25% lower than term controls (9.4 vs 12.6 × 10^-4 minutes^-1 ·[mU/L]; P = .001). Other parameters of glucose metabolism, including fasting insulin levels, were similar in the two groups. The awake systolic blood pressure (from 24-hour monitoring) tended to be 3.1 mm Hg higher on average in children born very preterm (P = .054), while the clinic systolic blood pressure was 5.4 mm Hg higher (P = .002).

CONCLUSIONS

Lower insulin sensitivity remains a feature of children born very preterm, despite improvements in neonatal intensive care. As reported in our original study, our findings suggest the defect in insulin action in prepubertal children born very pretermis primarily peripheral and not hepatic.