Spontaneous breathing or mechanical ventilation alters lung compliance and tissue association of exogenous surfactant in preterm newborn rabbits

Comparing the Effects of Two Surfactant Administration Methods: Minimally Invasive Surfactant Therapy (MIST) with Intubation (INSURE) in Infants with Respiratory Distress Syndrome

BACKGROUND

The aim of this study is to investigate and compare the effects of administering a surfactant through a fine intra-tracheal catheter during spontaneous breathing with the usual INSURE method in premature infants.

MATERIALS AND METHODS

In this clinical trial, premature babies with respiratory distress syndrome who required surfactant administration were randomly assigned to two groups: an intervention group (MIST) and a control group (INSURE). The treatment results were compared in terms of complications related to treatment (desaturation, apnea, bradycardia, and surfactant reflux), respiratory complications (requirement for mechanical ventilation, duration of nCPAP, duration of oxygen requirement, frequency of pneumothorax, and pulmonary hemorrhage), complications related to prematurity (incidence of IVH, NEC, BPD, and PDA), the need for a second dose of surfactant, and the duration of hospitalization.

RESULTS

a total of 160 premature babies with a gestational age of 26-34 weeks were randomly divided into two groups. The results showed that the need for mechanical ventilation, the duration of CPAP needed, and the duration of oxygen therapy were significantly lower in the MIST group than in the INSURE group. Additionally, the incidence of BPD was less common in the MIST group compared to the INSURE group. However, surfactant reflux was more common in the MIST group than in the INSURE group. There were no significant differences between the two groups in other outcomes, including the length of hospital stay and complications such as IVH, PDA, NEC, pneumothorax, and pulmonary hemorrhage.

CONCLUSION

The results of this research demonstrate that the less invasive method of surfactant therapy (MIST) is a feasible, effective, and low-risk alternative to the INSURE method.

Influence of catheter thickness on respiratory physiology during less invasive surfactant administration in extremely preterm infants

Introduction

Delivering surfactant via thin catheters (minimal-invasive surfactant therapy (MIST); less invasive surfactant administration (LISA)) has become a common procedure. However, the effect of tracheal obstruction caused by catheters of different sizes on tracheal resistance in extremely low gestational age newborns (ELGANs) is unknown.

Methods

To investigate the effect of catheters size 3.5, 5 and 6 French on airway resistance in ELGANs of 23-28 weeks gestational age during LISA, we performed calculations based on Hagen-Poiseuille's law and compared these with a clinically and physically more accurate method: computational fluid dynamics (CFD) simulations of respiratory airflow, performed in 3D virtual airway models derived from MRI.

Results

The presence of the above catheters decreased the cross-sectional area of the infants' tracheal entrance (the cricoid ring) by 13-53%. Hagen-Poiseuille's law predicted an increase in resistance by 1.5-4.5 times and 1.3-2.6 times in ELGANs born at 23 and 28 weeks, respectively. However, CFD simulations demonstrated an even higher increase in resistance of 3.4-85.1 and 1.1-3.5 times, respectively. The higher calculated resistances were due to the extremely narrow remaining lumen at the glottis and cricoid with the catheter inserted, resulting in a stronger glottal jet and turbulent airflow, which was not predicted by Hagen-Poiseuille.

Conclusion

Catheter thickness can greatly increase tracheal resistance during LISA-procedures in ELGANs. Based on these models, it is recommended to use the thinnest catheter possible during LISA in ELGANs to avoid unnecessary increases in airway resistance in infants already experiencing dyspnea due to respiratory distress syndrome.

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

Importance

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

Objective

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

Design, Setting, and Participants

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

Intervention

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

Main Outcomes and Measures

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

Results

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

Conclusions and Relevance

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

Trial Registration

EudraCT: 2016-004198-41.

Alternative routes of surfactant application - An update

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

Surfactant delivery strategies to prevent bronchopulmonary dysplasia

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

Is Less Invasive Surfactant Administration Better than INtubation-SURfactant-Extubation for Prophylactic Surfactant Replacement Therapy?

Purpose: The study aimed to examine whether prophylactic surfactant replacement therapy (SRT) with less invasive surfactant administration (LISA) by tracheal catheterization in a group of spontaneously breathing preterm infants would improve clinical outcomes compared to prophylactic SRT with the INtubation-SURfactantExtubation (INSURE) method.Methods: We compared 20 spontaneously breathing preterm infants, 25 to 29 weeks of gestation or with a birth weight of less than 1,250 g, treated with prophylactic SRT using a gastric tube (LISA group), to the 20 spontaneously breathing preterm infants matched by gestational age and birth weight, managed with prophylactic SRT via the INSURE method (INSURE group, historical control).Results: The LISA group had lower rates of mechanical ventilation (MV) 72 hours after birth (P=0.019) and at any time (P=0.025), lower frequency of bradycardia during SRT (P=0.031), and lower median duration of MV than the INSURE group (P=0.038). In multivariate analysis, the LISA method was associated with a significantly lower likelihood of receiving invasive ventilation during hospitalization (odds ratio [OR], 0.029; 95% confidence interval [CI], 0.001 to 0.938; P=0.046) and a decreased frequency of bradycardia during SRT (OR, 0.020; 95% CI, 0.001 to 0.535; P=0.020) as compared to the INSURE method.Conclusion: Prophylactic SRT using LISA via tracheal catheterization in preterm infants may significantly reduce exposure to MV during hospitalization and bradycardia during surfactant administration.

Impact of early respiratory care for extremely preterm infants

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

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.

Non-destructive vacuum-assisted measurement of lung elastic modulus

In living tissues, mechanical stiffness and biological function are intrinsically linked. Alterations in the stiffness of tissues can induce pathological interactions that affect cellular activity and tissue function. Underlying connections between tissue stiffness and disease highlights the importance of accurate quantitative characterizations of soft tissue mechanics, which can improve our understanding of disease and inform therapeutic development. In particular, accurate measurement of lung mechanical properties has been especially challenging due to the anatomical and mechanobiological complexities of the lung. Discrepancies between measured mechanical properties of dissected lung tissue samples and intact lung tissues in vivo has limited the ability to accurately characterize integral lung mechanics. Here, we report a non-destructive vacuum-assisted method to evaluate mechanical properties of soft biomaterials, including intact tissues and hydrogels. Using this approach, we measured elastic moduli of rat lung tissue that varied depending on stress-strain distribution throughout the lung. We also observed that the elastic moduli of enzymatically disrupted lung parenchyma increased by at least 64%. The reported methodology enables assessment of the nonlinear viscoelastic characteristics of intact lungs under normal and abnormal (i.e., injured, diseased) conditions and allows measurement of mechanical properties of tissue-mimetic biomaterials for use in therapeutics or in vitro models. STATEMENT OF SIGNIFICANCE: Accurate quantification of tissue stiffness is critical for understanding mechanisms of disease and developing effective therapeutics. Current modalities to measure tissue stiffness are destructive and preclude accurate assessment of lung mechanical properties, as lung mechanics are determined by complex features of the intact lung. To address the need for alternative methods to assess lung mechanics, we report a non-destructive vacuum-based approach to quantify tissue stiffness. We applied this method to correlate lung tissue mechanics with tissue disruption, and to assess the stiffness of biomaterials. This method can be used to inform the development of tissue-mimetic materials for use in therapeutics and disease models, and could potentially be applied for in-situ evaluation of tissue stiffness as a diagnostic or prognostic tool.

Supraglottic airway devices for administration of surfactant to newborn infants with respiratory distress syndrome: a narrative review

Surfactant is an effective treatment for respiratory distress syndrome, being particularly important for infants in whom continuous positive airway pressure (CPAP) provides insufficient support. Supraglottic airway devices present an attractive option for surfactant delivery, particularly as an alternative to methods dependent on direct laryngoscopy, a procedural skill that is both difficult to learn and in which to maintain competence. Published studies provide encouraging data that surfactant administration by supraglottic airway device can be performed with a high rate of success and may reduce the need for subsequent intubation compared with either continued CPAP or surfactant administration via endotracheal tube. However, existing randomised controlled trials (RCTs) are heterogeneous in design and include just over 350 infants in total. To date, all RCT evidence has been generated in tertiary units, whereas the greatest potential for benefit from the use of these devices is likely to be in non-tertiary settings. Future research should investigate choice and utility of device in addition to safety and effectiveness of procedure. Importantly, studies conducted in non-tertiary settings should evaluate feasibility, meaningful clinical outcomes and the impact that this approach might have on infants and their families. Supraglottic airway devices may represent a simple and effective mode of surfactant administration that can be widely used by a variety of clinicians. However, further well-designed RCTs are required to determine their role, safety and effectiveness in both tertiary and non-tertiary settings before introduction into routine clinical practice.

LISA/MIST: Complex clinical problems almost never have easy solutions

Over the last 10 years, new techniques to administer surfactant have been promoted, based on their presumed lesser invasiveness and they have been generally called LISA (less invasive surfactant administration). We believe that the clinical potential of LISA techniques is currently overestimated. LISA lacks biological and pathophysiological background justifying its potential benefits. Moreover, LISA has been investigated in clinical trials without previous translational data and these trials are affected by significant flaws. The available data from these trials only allow to conclude that LISA is better than prolonged, unrestricted invasive ventilation with loosely described parameters, a mode of respiratory support that should be anyway avoided in preterm infants. We urge the conduction of high-quality studies to understand how to choose and titrate analgesia/sedation and optimize surfactant administration in preterm neonates. We offer a comprehensive, evidence-based review of the clinical data on LISA, their biases and the lack of physiopathology background.

Less invasive surfactant administration reduces incidence of severe intraventricular haemorrage in preterms with respiratory distress syndrome: a cohort study

OBJECTIVE

Less invasive surfactant administration (LISA) has proved to safely improve morbidity in extreme preterms with respiratory distress syndrome (RDS). Its effect regarding intraventricular hemorrhage (IVH) remains controversial between most recent systematic reviews. We aimed to evaluate its effect over incidence of severe IVH in this population.

STUDY DESIGN

We compared the incidence of IVH in a prospective cohort of consecutively born preterm infants <34 weeks' gestation receiving LISA (n = 108) with a historical cohort receiving surfactant delivery via tracheal tube and managed with mechanical ventilation (n = 100).

RESULTS

No significant differences regarding perinatal characteristics were observed between both groups. There was a significant reduction in the incidence of severe IVH in LISA group as compared with the historical group [OR = 0.054 (95% CI 0.01-0.2) p = 0.000. NNT 5]. In addition, a significant trend towards decreased mortality was also observed in the study group [OR = 0.2 (95% CI 0.04-0.9) p = 0.027, NNT 9]. Intervention group infants also showed lower oxygenation requirements during the first 72 h post surfactant administration and a reduced incidence of pneumothorax. They were less frequently intubated [31 infants (28.4%) vs. 100 [100%]; P < 0.001] and required fewer days of mechanical ventilation. However, no significant difference in bronchopulmonary dysplasia incidence was observed between both groups.

CONCLUSIONS

LISA approach effectively reduces severe IVH in very low and low birth weight (BW) preterms with RDS. In addition we observe a significant trend towards reduction in both need and duration of MV support, air leak, and overall mortality in the intervention group.

Small Molecule Inhibitor Adjuvant Surfactant Therapy Attenuates Ventilator- and Hyperoxia-Induced Lung Injury in Preterm Rabbits

Background

Invasive mechanical ventilation (IMV) has become one of the mainstays of therapy in NICUs worldwide, as a result of which premature babies with extremely low birth weight have been able to survive. Although lifesaving, IMV can result in lung inflammation and injury. Surfactant therapy is considered a standard of care in preterm infants with immature lungs. Recently, small molecule inhibitors like siRNAs and miRNAs have been used for therapeutic purposes. Ddit3 (CHOP), Ang2 and miR34a are known to be upregulated in experimental lung injury. We wanted to test whether inhibitors for these molecules (CHOP siRNA, Ang2 siRNA, and miR34a antagomir) if used alone or with a combination with surfactant (Curosurf^®) would help in reducing ventilation and hyperoxia-induced injury in an experimental lung injury model.

Methods

Preterm rabbits born by cesarean section were intratracheally instilled with the three small molecule inhibitors with or without Curosurf^® prior to IMV and hyperoxia exposure. Prior to testing the inhibitors in rabbits, these small molecule inhibitors were transfected in mouse lung epithelial cells (MLE12 and AECII) and delivered to neonatal mouse pups intranasally as a proof of concept that surfactant (Curosurf^®) could be used as an effective vehicle for administration of such drugs. Survival, pulmonary function tests, histopathology, immunostaining, quantitative PCR and western blotting were done to see the adjuvant effect of surfactant with these three small molecule inhibitors.

Results

Our data shows that Curosurf^® can facilitate transfection of small molecules in MLE12 cells with the same and/or increased efficiency as Lipofectamine. Surfactant given alone or as an adjuvant with small molecule inhibitors increases survival, decreases IMV and hyperoxia-induced inflammation, improves pulmonary function and lung injury scores in preterm rabbit kits.

Conclusion

Our study shows that Curosurf^® can be used successfully as an adjuvant therapy with small molecule inhibitors for CHOP/Ang2/miR34a. In this study, of the three inhibitors used, miR34a inhibitor seemed to be the most promising compound to combat IMV and hyperoxia-induced lung injury in preterm rabbits.

Minimally invasive surfactant therapy versus intubation for surfactant administration in very low birth weight infants with respiratory distress syndrome

BACKGROUND

Minimally invasive surfactant therapy (MIST) is a new mode of surfactant administration without intubation to spontaneously breathing preterm infants with respiratory distress syndrome (RDS). The aims of this study were to assess the feasibility, efficacy and safety of using MIST to give surfactant for very low birth weight (VLBW) infants with RDS.

METHODS

In total, 53 VLBW infants who were born before 32 gestational weeks with spontaneous breathing, respiratory distress, and requiring surfactant therapy were divided into two groups. The infants in group A (n = 29) were intubated and received surfactant replacement therapy via endotracheal tube, followed by mechanical ventilation (MV). The infants in group B (n = 24) received tracheal instillation of surfactant via a semirigid vascular catheter during spontaneous breathing under nasal continuous positive airway pressure (nCPAP). After surfactant instillation, the infants in group B were still placed on nCPAP.

RESULTS

Our data showed that infants in group B (MIST group) had significantly lower rate (P < 0.05) of composite outcome of death or bronchopulmonary dysplasia (BPD), duration of intermittent positive airway pressure ventilation (IPPV) or MV, drug treatment of patent ductus arteriosus (PDA), and surgical ligation of PDA than group A.

CONCLUSION

MIST is feasible, safe and it may reduce the composite outcome of death or BPD for VLBW infants with RDS requiring surfactant replacement therapy.

Effects of less invasive surfactant administration (LISA) via a gastric tube on the treatment of respiratory distress syndrome in premature infants aged 32 to 36 weeks

To explore the clinical effects of less invasive surfactant administration (LISA) via a gastric tube on the treatment of respiratory distress syndrome (RDS) in premature infants aged 32 to 36 weeks.A total of 97 premature infants with RDS admitted to the Children's Hospital of Shanxi from February 2017 to January 2018 were randomly divided into LISA (47 cases) and (intubation-surfactant-extubation,) INSURE groups (50 cases). In the LISA group, 6F gastric tubes were inserted into the trachea through direct laryngoscopy under nasal continuous positive airway pressure (NCPAP), and pulmonary surfactant (PS) was injected. In the INSURE group, PS was injected via tracheal intubation and NCPAP was performed after extubation. The incidence of technical-related adverse events and various complications in the two groups were observed.PS was successfully injected through gastric tube in the LISA group. There were no significant differences in reflux, asphyxia, bradycardia (<100 beats/min), apnea, FiO2, changes in PaO2 and PaCO2 at 1 hour post-treatment between the groups. During the course of administration, blood pressure and SpO2 in the LISA group were more stable, and significant differences between the 2 groups were observed. However, no significant differences in the complications and outcomes between the 2 groups occurred.The LISA technique can be used to treat premature infants with RDS aged 32 to 36 weeks with stronger spontaneous breathing ability. Further clinical studies are required to determine the optimal strategy of LISA administration and the most profitable patient population.

Criteria for Using INSURE in Management of Premature Babies with Respiratory Distress Syndrome

Introduction

Respiratory distress syndrome (RDS) is defined as acute respiratory distress caused by surfactant deficiency that disturbs gas exchange in preterm infants. It is one of the most common neonatal problems and has been considered to be the most common cause of mortality and morbidity in preterm babies.

Aim

In this study, different variables were studied to predict factors for INSURE failure that might help in choosing infants for this procedure early.

Methods

Sixty three (63) patients were enrolled in this study as they met the inclusion criteria. All neonates were intubated briefly less than 2 hours, given natural surfactant in the dose of 3 ml/kg. As soon as it was appropriate and the neonate was stable in the form of normal heart rate and oxygenation, extubation was done and the baby connected to NCPAP at a pressure of 6 cmH2O. INSURE failure was considered if the patient needed mechanical ventilation for more than 72 hours while INSURE success was considered if we were able to wean the patient from CPAP or if the patient didn't need mechanical ventilation in the first 72 hours after surfactant administration. The indications for mechanical ventilation after INSURE procedure were respiratory distress with desaturation (02 sat less than 90%), recurrent apnea, Pco2 more than 60 mmHg.

Results

Since INSURE procedure is being largely applied in the neonatal intensive care units, it is important to determine the candidate neonate for this procedure with the minimum failure rate. Although the sample of our study is small, but we can suggest that neonate with gestational age less than 28, birth weight less than 1000 gm, umbilical PH of less than 7, low Apgar score and anemic patients are at high risk for INSURE failure.

Conclusion

Early diagnosis of PDA and IVH is essential to avoid INSURE method in these patients.

Surfactant therapy in premature babies: SurE or InSurE

BACKGROUND

Preterm infants with respiratory distress syndrome (RDS) requiring surfactant therapy have been traditionally receiving surfactant by intubation surfactant and extubation technique (InSurE), which comprises of tracheal intubation, surfactant administration, and extubation. However, more recently noninvasive methods like least invasive surfactant therapy or minimally invasive surfactant therapy have been reported to be successful. These methods, avoid intubation thus minimize airway trauma and avoid barotrauma. The primary aim of this randomized trial was to compare the need for mechanical ventilation (MV) between the administration of surfactant via a thin catheter during spontaneous breathing and the InSurE technique.

METHODS

Preterm infant's ≤34 weeks with RDS requiring continuous positive airway pressure (CPAP) within 6 hours of life were prospectively randomized to receive early surfactant either by SurE (surfactant without endotracheal tube intubation) or InSurE technique. The need for MV within the first 72 hours and other related outcomes were analyzed between the two groups.

RESULTS

One hundred seventy-five infants in each group were analyzed. The need for MV in the first 72 hours of life was significantly lower in the SurE group compared to the InSurE group (19% vs 40%, P < .01). Similarly, duration of oxygen therapy and hospital stay were significantly shorter in the SurE group. Furthermore, bronchopulmonary dysplasia (BPD) rate was significantly lower among the infants administered surfactant by the SurE technique.

CONCLUSION

In preterm neonates with RDS who are stabilized on CPAP, the SurE technique for surfactant delivery results in the reduced need for MV and also may decrease the rate of BPD in some vulnerable subpopulations.

The influence of the technique of surfactant administration (LISA vs INSURE) on the outcomes of respiratory distress syndrome treatment in preterm infants

OBJECTIVE

Intratracheal administration of exogenous surfactant is a well-established therapy for respiratory distress syndrome in preterm infants. The two preferred methods for respiratory support in neonates that contribute to limiting the risk of lung damage associated with mechanical ventilation include nCPAP and non-invasive ventilation. The increasing popularity of surfactant administration techniques is due to the fact they reduce the time of mechanical ventilation until this medication is administered. In some cases a short period of mechanical ventilation follows (INSURE: INtubation-SURfactant-Extubation). There are also methods that make it possible to completely avoid intubation and help maintain spontaneous breathing during surfactant administration (LISA: Less Invasive Surfactant Administration, MIST: Minimal Invasive Surfactant Therapy). Aim: To analyze treatment outcomes in preterm infants who suffer from respiratory distress syndrome and require exogenous surfactant administration depending on the technique used: LISA vs INSURE.

PATIENTS AND METHODS

Material and methods: The present retrospective analysis included 129 infants born at a gestational age of between 24 and 33 weeks who were hospitalized in the Neonatology Department in the years 2014-2016, were administered surfactant and remained on non-invasive ventilation. All the subjects received only proractant alfa. Both study groups: LISA (n=83) and INSURE (n=46) were analyzed in terms of respiratory distress treatment outcomes and the presence of complications of prematurity.

RESULTS

Results: There were no significant differences in patient characteristics between the two study groups (LISA vs INSURE: mean birth body weight was 1210 g vs 1275 g, respectively; mean gestational age at birth was 30 weeks vs 29 6/7 weeks, respectively). The comparison of respiratory support method and FiO2 concentration within the first 72 hours after surfactant administration showed no significant differences between the groups. Similarly, respiratory outcomes did not significantly differ between the LISA and INSURE groups and were: the need for intubation ⎼ 42.2% vs 32.6%, p=0.201, duration of mechanical ventilation - median days 0 vs 0, p=0.377, duration of nCPAP - median days 5 vs 5, p=0.379, duration of oxygen supplementation - median days 1 vs 1, p=0.555, and the incidence of bronchopulmonary dysplasia - 28.9% vs 23.9%, p=0.506. Also, the incidence of complications was similar in both study groups.

CONCLUSION

Conclusions: Our retrospective analysis of preliminary outcomes of surfactant administration involving the use of the LISA technique showed no statistically significant differences as compared with the INSURE method. The randomized, prospective study that is currently being conducted at our Neonatology Department and includes biochemical markers of lung damage, will bring more objective data on the safety and effectiveness of both surfactant administration techniques (LISA vs INSURE).

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Surfactant Administration via Thin Catheter: A Practical Guide

Exogenous surfactant replacement is the most effective evidence-based therapy for respiratory distress syndrome in preterm infants. The mode of administration has evolved in the last decade towards less invasive techniques that aim to effectively provide an adequate dose of surfactant, while allowing spontaneous respiration to continue, and with the support of continuous positive airway pressure. Surfactant delivery via aerosolisation, pharyngeal instillation, and laryngeal mask are being actively pursued in research, but have not yet been adopted to any significant degree in clinical practice. Surfactant administration via thin catheter, on the other hand, is becoming more widely used in neonatal intensive care units worldwide and is now an acknowledged alternative to the standard mode of surfactant delivery. Different devices, including nasogastric tubes, vascular catheters, and purpose-built surfactant instillation catheters are used. We present here a contemporary review of surfactant administration via thin catheter, in a practical guide format that reflects the individual and collective scientific opinions of the clinicians who participated in formulating the guide.

Bronchopulmonary Dysplasia: An Update of Current Pharmacologic Therapies and New Approaches

Bronchopulmonary dysplasia (BPD) remains the most prevalent long-term morbidity of surviving extremely preterm infants and is associated with significant health care utilization in infancy and beyond. Recent advances in neonatal care have resulted in improved survival of extremely low birth weight (ELBW) infants; however, the incidence of BPD has not been substantially impacted by novel interventions in this vulnerable population. The multifactorial cause of BPD requires a multi-pronged approach for prevention and treatment. New approaches in assisted ventilation, optimal nutrition, and pharmacologic interventions are currently being evaluated. The focus of this review is the current state of the evidence for pharmacotherapy in BPD. Promising future approaches in need of further study will also be reviewed.

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

In the last 4 decades, advances in neonatology have led to a significant increase in the survival of preterm infants. One of the biggest advances was the introduction of surfactant replacement therapy for the treatment of respiratory distress syndrome. This is the main cause of respiratory insufficiency in preterm infants and is one of the major causes of perinatal morbidity and mortality. Surfactant replacement therapy is already a well-investigated and established therapy in neonatology. However, surfactant replacement therapy has progressed and been refined over recent decades, especially with the increasing care for preterm infants born before 26 weeks' gestational age and the recent clinical focus on avoiding mechanical ventilation. Clinical evidence is evolving on new types of surfactant, surfactant dosages, co-medication given before, with, or after surfactant replacement, and new technical advances regarding the mode of administration.

Less invasive surfactant administration versus intubation for surfactant delivery in preterm infants with respiratory distress syndrome: a systematic review and meta-analysis

CONTEXT

In spontaneously breathing preterm infants with respiratory distress syndrome (RDS) receiving nasal continuous positive airway pressure, a method of less invasive surfactant administration (LISA) using a thin catheter has been described as an alternative to endotracheal intubation for surfactant delivery to reduce lung injury.

OBJECTIVE

A systematic review of randomised controlled trials (RCTs) comparing LISA with the standard method of surfactant delivery for clinical outcomes.

METHODS

Medline, CENTRAL and Embase databases were searched (until 29 October 2015). Additional citations were identified from trial registries, conference proceedings and the bibliographies of selected articles. The included studies were RCTs enrolling preterm infants with RDS and compared LISA technique with intubation for surfactant delivery for any of the prespecified clinical outcomes.

RESULTS

Six RCTs were identified, enrolling a total of 895 infants. The use of LISA technique reduced the composite outcome of death or bronchopulmonary dysplasia (BPD) at 36 weeks (risk ratio (RR)=0.75 (95% CI 0.59 to 0.94), p=0.01), BPD₃₆ among survivors (RR=0.72 (0.53 to 0.97), p=0.03), need for mechanical ventilation within 72 hours of birth (RR=0.71 (0.53 to 0.96), p=0.02) or need for mechanical ventilation anytime during the neonatal intensive care unit stay (RR=0.66 (0.47 to 0.93), p=0.02). There were no differences noted for the outcome of death and other neonatal morbidities. Procedure failure rate on the first attempt and the need for additional doses of surfactant were not different between the intervention groups.

CONCLUSIONS

LISA technique for surfactant delivery results in a lesser need for mechanical ventilation in infants with RDS, reduction in the composite outcome of death or BPD at 36 weeks, and BPD₃₆ among survivors.

Surfactant instillation in spontaneously breathing preterm infants: a systematic review and meta-analysis

Less invasive surfactant therapies (LIST) use surfactant instillation through a thin tracheal catheter in spontaneously breathing infants. This review and meta-analysis investigates respiratory outcomes for preterm infants with respiratory distress syndrome treated with LIST rather than administration of surfactant through an endotracheal tube. Randomised controlled trial (RCT) full texts provided outcome data for bronchopulmonary dysplasia (BPD), death or BPD, early CPAP failure, invasive ventilation requirements and usual neonatal morbidities. Relative risks (RR) from pooled data, with subgroup analyses, were obtained from a Mantel-Haenszel analysis using a random effect model. Six RCTs evaluated LIST: 4 vs InSurE and 1 each vs delayed or immediate intubation for surfactant. LIST resulted in decreased risks of BPD (RR = 0.71 [0.52-0.99]; NNT = 21), death or BPD (RR = 0.74 [0.58-0.94]; NNT = 15) and early CPAP failure or invasive ventilation requirements (RR = 0.67 [0.53-0.84]; NNT = 8 and RR = 0.69 [0.53-0.88]; NNT = 6). Compared to InSurE, LIST decreased the risks of BPD or death (RR = 0.63 [0.44-0.92]; NNT = 11) and of early CPAP failure (RR = 0.71 [0.53-0.96]; NNT = 11). Common neonatal morbidities were not different.

CONCLUSIONS

Respiratory management with LIST decreases the risks of BPD and BPD or death, and the need for invasive ventilation. This strategy appears safe, but long-term follow-up is lacking. What is Known: • Initial management of preterm infants with CPAP decreases the risk of death or BPD, but many still require surfactant or invasive ventilation. • Surfactant can be instilled through a tracheal thin catheter while the infant breathes on CPAP, but improvement in BPD is inconsistent between studies. What is New: • Less invasive surfactant therapy (LIST) strategies decrease the risks of BPD, of death or BPD, and of CPAP failure compared to strategies where surfactant is administered through an endotracheal tube. • LIST strategies decrease the risks of the composite outcome of BPD or death and of early CPAP failure when compared to "intubation-surfactant-extubation" approaches.

Randomized trial of laryngeal mask airway versus endotracheal intubation for surfactant delivery

OBJECTIVE

To compare the effectiveness of surfactant delivery via endotracheal tube (ETT) using an intubation-surfactant-rapid extubation approach with premedication) vs laryngeal mask airway (LMA) in preventing the need for mechanical ventilation in preterm neonates with moderate respiratory distress syndrome (RDS).

STUDY DESIGN

Moderately preterm infants diagnosed with RDS, receiving nasal continuous positive airway pressure with FiO2 0.30 to 0.60, were randomized to two groups at age 3 to 48 h. Those in the ETT group were intubated following premedication with atropine and morphine, whereas the LMA group received only atropine. Both groups received calfactant before a planned reinstitution of nasal continuous positive airway pressure, and had equivalent pre-specified criteria for subsequent mechanical ventilation and surfactant retreatment. The primary outcome was failure of surfactant treatment strategy to avoid mechanical ventilation; we differentiated early from late failures to assess the contribution of potential mechanisms such as respiratory depression versus less-effective surfactant delivery. Secondary outcomes addressed efficacy and safety end points.

RESULT

Sixty-one patients were randomized, one excluded and 30 analyzed in each group, with similar baseline characteristics. Failure rate was 77% in the ETT group and 30% in the LMA group (P<0.001). The difference was related to early failure, as late failure rates did not differ between groups. FiO2 decrease after surfactant and rates of adverse events were similar between groups.

CONCLUSION

Surfactant therapy through an LMA decreases the proportion of newborns with moderate RDS who require mechanical ventilation, when compared with a standard endotracheal intubation procedure with sedation. The efficacy of surfactant in decreasing RDS severity appears similar with both methods. Morphine premedication likely contributed to early post-surfactant failures.

Less invasive beractant administration in preterm infants: a pilot study

OBJECTIVES

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

METHOD

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

RESULTS

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

CONCLUSION

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

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

Background

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

Methods/design

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

Discussion

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

Trial registration

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

Effects of less-invasive surfactant administration on oxygenation, pulmonary surfactant distribution, and lung compliance in spontaneously breathing preterm lambs

BACKGROUND

A new technique was proposed to administer surfactant to spontaneous breathing preterm infants by placing a thin catheter through the vocal cords. This technique was not studied with respect to oxygenation, gas exchange, surfactant distribution, and lung mechanics. We tested the technique of less-invasive surfactant administration (LISA) in a spontaneous breathing preterm lamb model.

METHODS

Preterm lambs (n = 12) of 133-134 d gestational age were randomized to the following three groups: (i) continuous positive airway pressure (CPAP) only, (ii) CPAP + LISA, and (iii) intubation and mechanical ventilation with surfactant administration. Surfactant was labeled with samarium oxide. During the next 180 min, blood gas analyses were performed. Postmortem, lungs were removed and surfactant distribution was assessed, and pressure-volume curves were performed.

RESULTS

Pao2 in the LISA-treated lambs was significantly higher than in the lambs that exclusively received CPAP. Moreover, Pao2 values were similar between the LISA-treated and the intubated lambs. Overall, surfactant deposition was less in the LISA lambs, with significantly less surfactant distributed to the right upper lobe. Lung compliance was better in the intubated lambs compared with the LISA-treated lambs, although this did not reach significance.

CONCLUSION

LISA improved oxygenation, similar to conventional surfactant application techniques, despite lower surfactant deposition and lung compliance.

Outcome of intubate surfactant rapidly extubate (InSuRE): an Indian experience

OBJECTIVE

To assess outcome of InSuRE (Intubation, Surfactant and Rapid Extubation) in managing preterm neonates with respiratory distress syndrome (RDS).

METHODS

Preterm neonates fulfilling inclusion criteria were enrolled after obtaining informed parental consent. Criteria for success of InSuRE was predefined. Proportion of neonates with success or failure of InSuRE was the primary outcome.

RESULTS

From August 2008 through July 2009, 28 babies underwent InSuRE. Sixteen babies (57 %) succeeded InSuRE. Median birth weight in successful group was 1362.5 (850-2,150) g and in failure group was 1,805 (990-2,560) g (p = 0.015). Nasal continuous positive airway pressure (nCPAP) was started at 0.5 (0-5.0) h of life in successful group and at 3.0 (0.5-6.0) h in failure group (p = 0.005). Babies in successful group received surfactant at median age of 2.0 (1.0-6.0) h, and in failure group at 4.0 (2.0-8.0) h (p = 0.002). Two patients in successful group died of neonatal sepsis, while none died in failure group (p = 0.492).

CONCLUSIONS

InSuRE is feasible in developing countries. However, we need large multicentric randomised controlled trials to prove the safety and efficacy in our settings.

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

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

Nasal CPAP and surfactant for treatment of respiratory distress syndrome and prevention of bronchopulmonary dysplasia

The Scandinavian approach is an effective combined treatment for respiratory distress syndrome (RDS) and prevention of bronchopulmonary dysplasia (BPD). It is composed of many individual parts. Of significant importance is the early treatment with nasal continuous positive airway pressure (nCPAP) and surfactant treatment. The approach may be supplemented with caffeine citrate and non-invasive positive pressure ventilation for apnoea. The low incidence of BPD seen as a consequence of the treatment strategy is mainly due to a reduced need for mechanical ventilation (MV).

CONCLUSION

Early-postnatal treatment with nCPAP and surfactant decreases the severity and mortality of RDS and BPD. This is mainly due to a diminished use of MV in the first days of life.

Aerosolised surfactant generated by a novel noninvasive apparatus reduced acute lung injury in rats

Introduction

Exogenous surfactant has been explored as a potential therapy for acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). In the present study, a nebuliser driven by oxygen lines found in the hospital was developed to deliver aerosolised porcine pulmonary surfactant (PPS). We hypothesised that aerosolised surfactant inhaled through spontaneous breathing may effectively reduce severe lung injury.

Methods

Rats were intravenously injected with oleic acid (OA) to induce ALI and 30 minutes later they were divided into five groups: model (injury only), PPS aerosol (PPS-aer), saline aerosol (saline-aer), PPS instillation (PPS-inst), and saline instillation (Saline-Inst). Blood gases, lung histology, and protein and TNF-α concentrations in the bronchoalveolar lavage fluid (BALF) were examined.

Results

The PPS aerosol particles were less than 2.0 μm in size as determined by a laser aerosol particle counter. Treatment of animals with a PPS aerosol significantly increased the phospholipid content in the BALF, improved lung function, reduced pulmonary oedema, decreased total protein and TNF-α concentrations in BALF, ameliorated lung injury and improved animal survival. These therapeutic effects are similar to those seen in the PPS-inst group.

Conclusions

This new method of PPS aerosolisation combines the therapeutic effects of a surfactant with partial oxygen inhalation under spontaneous breathing. It is an effective, simple and safe method of administering an exogenous surfactant.

Deleted in Malignant Brain Tumors 1 (DMBT1) is present in hyaline membranes and modulates surface tension of surfactant

BACKGROUND

Deleted in Malignant Brain Tumors 1 (DMBT1) is a secreted scavenger receptor cysteine-rich protein that binds various bacteria and is thought to participate in innate pulmonary host defense. We hypothesized that pulmonary DMBT1 could contribute to respiratory distress syndrome in neonates by modulating surfactant function.

METHODS

DMBT1 expression was studied by immunohistochemistry and mRNA in situ hybridization in post-mortem lungs of preterm and full-term neonates with pulmonary hyaline membranes. The effect of human recombinant DMBT1 on the function of bovine and porcine surfactant was measured by a capillary surfactometer. DMBT1-levels in tracheal aspirates of ventilated preterm and term infants were determined by ELISA.

RESULTS

Pulmonary DMBT1 was localized in hyaline membranes during respiratory distress syndrome. In vitro addition of human recombinant DMBT1 to the surfactants increased surface tension in a dose-dependent manner. The DMBT1-mediated effect was reverted by the addition of calcium depending on the surfactant preparation.

CONCLUSION

Our data showed pulmonary DMBT1 expression in hyaline membranes during respiratory distress syndrome and demonstrated that DMBT1 increases lung surface tension in vitro. This raises the possibility that DMBT1 could antagonize surfactant supplementation in respiratory distress syndrome and could represent a candidate target molecule for therapeutic intervention in neonatal lung disease.

Mechanical ventilation down-regulates surfactant protein A and keratinocyte growth factor expression in premature rabbits

Surfactant-associated proteins (SP-A, SP-B, and SP-C) are critical for the endogenous function of surfactant. Keratinocyte growth factor (KGF) and vascular endothelial growth factor (VEGF) are key regulators of lung development. The objective of this study was to evaluate the effects of early mechanical ventilation on the expression of these important regulatory proteins in a preterm rabbit model. Premature fetuses were delivered at 29 d of gestation and randomized to necropsy at birth, i.e. no ventilation (NV), spontaneous breathing (SB), or mechanical ventilation (MV) for 16 h. MV animals were further randomized to treatment with dexamethasone (dex). Our findings showed that SB rabbits increased their expression of SP-A mRNA and protein after birth compared with NV controls. MV significantly attenuated this response in the absence of dex. Exposure to dex elevated SP-B mRNA expression in both SB and MV rabbits. KGF protein levels were markedly increased in SB animals compared with MV counterparts. VEGF levels were similar in SB and MV animals, but were significantly increased compared with NV controls. These data suggest that MV alters surfactant-associated protein and growth factor expression, which may contribute to injury in the developing lung.

Implementation of surfactant treatment during continuous positive airway pressure

OBJECTIVE

To study the effects of implementing a method for surfactant administration by transient intubation, INSURE (i.e. INtubation SURfactant Extubation) during nasal continuous positive airway pressure (nCPAP) for moderately preterm infants with respiratory distress syndrome (RDS).

STUDY DESIGN

A descriptive, retrospective, bi-center study in Stockholm, Sweden, comparing mechanical ventilation (MV) rates, surfactant use, treatment response and outcome of all inborn infants with gestational age 27 to 34 weeks and RDS, (n=420), during the 5-year periods before and after the introduction of the INSURE-strategy at one of the centers (Karolinska Huddinge) in 1998. The other center (Karolinska Solna) continued conventional surfactant therapy in conjunction with MV throughout the study.

RESULTS

Implementation of INSURE at Karolinska Huddinge reduced the number of infants requiring MV by 50% (P<0.01), resulted in earlier surfactant administration and increased overall surfactant use. INSURE-treatment improved oxygenation and the treatment response was sustained over time with only 17% of the infants requiring >1 dose of surfactant. At Karolinska Solna, the MV rates were unaltered between the first and second 5-year period.

CONCLUSION

Implementing a strategy of surfactant administration by transient intubation during nCPAP reduces the need for MV without adverse effects on outcome and may be an option to more effectively treat RDS, particularly in a care setting where transfer is necessary to provide MV.

Nasal CPAP has become an indispensable part of the primary treatment of newborns with respiratory distress syndrome

Prenatal steroids, early nasal CPAP combined with early surfactant treatment followed by extubation to nasal CPAP, and if necessary mechanical ventilation is a very effective treatment of respiratory distress syndrome. This treatment package is part of the 'Scandinavian model' for treatment of very-low-birthweight infants which also comprises gentle ventilation at birth; minimal handling; 'neonatal individualized development care and assessment program'; high priority of breast feeding; and use of kangaroo method and which facilitates observation and nursing of sick premature infants and optimizes the possibility for early mother-child contact. The incidence of bronchopulmonary dysplasia seems to be less of a problem in centres preferring nasal CPAP as the primary treatment for respiratory distress syndrome.