Less invasive surfactant administration: a word of caution

Less invasive surfactant administration methods: Who, what and how

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

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.

NON-pharmacological Approach Less Invasive Surfactant Administration (NONA-LISA) trial: protocol for a randomised controlled trial

INTRODUCTION

Using pre-procedure analgesia with the risk of apnoea may complicate the Less Invasive Surfactant Administration (LISA) procedure or reduce the effect of LISA.

METHODS

The NONA-LISA trial (ClinicalTrials.gov, NCT05609877) is a multicentre, blinded, randomised controlled trial aiming at including 324 infants born before 30 gestational weeks, meeting the criteria for surfactant treatment by LISA. Infants will be randomised to LISA after administration of fentanyl 0.5-1 mcg/kg intravenously (fentanyl group) or isotonic saline solution intravenously (saline group). All infants will receive standardised non-pharmacological comfort care before and during the LISA procedure. Additional analgesics will be provided at the clinician's discretion. The primary outcome is the need for invasive ventilation, meaning mechanical or manual ventilation via an endotracheal tube, for at least 30 min (cumulated) within 24 h of the procedure. Secondary outcomes include the modified COMFORTneo score during the procedure, bronchopulmonary dysplasia at 36 weeks, and mortality at 36 weeks.

DISCUSSION

The NONA-LISA trial has the potential to provide evidence for a standardised approach to relief from discomfort in preterm infants during LISA and to reduce invasive ventilation. The results may affect future clinical practice.

IMPACT

Pre-procedure analgesia is associated with apnoea and may complicate procedures that rely on regular spontaneous breathing, such as Less Invasive Surfactant Administration (LISA). This randomised controlled trial addresses the effect of analgesic premedication in LISA by comparing fentanyl with a placebo (isotonic saline) in infants undergoing the LISA procedure. All infants will receive standardised non-pharmacological comfort. The NONA-LISA trial has the potential to provide evidence for a standardised approach to relief from discomfort or pain in preterm infants during LISA and to reduce invasive ventilation. The results may affect future clinical practice regarding analgesic treatment associated with the LISA procedure.

Comparison of mortality and short-term outcomes between classic, intubation-surfactant-extubation, and less invasive surfactant administration methods of surfactant replacement therapy

Background

Intubation-Surfactant-Extubation (InSurE) and less invasive surfactant administration (LISA) are alternative surfactant replacement therapy methods for reducing the complications associated with invasive mechanical ventilation. This study aimed to compare the Classic, InSurE, and LISA methods in Very-Low-Birth-Weight infants (VLBWIs) in South Korea.

Methods

The Korean Neonatal Network (KNN) enrolled VLBWIs born between January 1, 2019 and December 31, 2020. They were analyzed retrospectively to compare the duration of respiratory support, length of hospitalization, mortality, and short-term outcomes of the three groups.

Results

The duration of invasive ventilator support was shorter in the following order: InSurE (3.99 ± 11.93 days), LISA (8.78 ± 29.32 days), and the Classic group (22.36 ± 29.94 days) (p = 0.014, p < 0.01) and InSurE had the shortest hospitalization (64.91 ± 24.07 days, p < 0.05) although the results couldn't adjust for confounding factor because of irregular distribution. InSurE had the lower risk of intraventricular hemorrhage (IVH) grade II-IV [odds ratio (OR) 0.524 [95% confidence interval (CI): 0.287-0.956], p = 0.035] than in the Classic group. Mortality was lower in the InSurE [OR 0.377 (95% CI: 0.146-0.978), p = 0.045] and LISA [OR 0.296 (95% CI: 0.102-0.862), p = 0.026] groups than in the Classic group. There was a reduced risk of moderate to severe bronchopulmonary dysplasia (BPD) [OR 0.691 (95% CI: 0.479-0.998, p = 0.049), OR 0.544 (95% CI: 0.355-0.831, p = 0.005), respectively], pulmonary hypertension [OR 0.350 (95% CI: 0.150-0.817, p = 0.015), OR 0.276 (95% CI: 0.107-0.713, p = 0.008), respectively], periventricular leukomalacia (PVL) [OR 0.382 (95% CI: 0.187-0.780, p = 0.008), OR 0.246 (95% CI: 0.096-0.627, p = 0.003), respectively], and patent ductus arteriosus (PDA) with treatment [OR 0.628 (95% CI: 0.454-0.868, p = 0.005), OR 0.467 (95% CI: 0.313-0.696, p < 0.001) respectively] in the InSurE and LISA groups compared to the Classic group.

Conclusion

InSurE showed the lowest duration of invasive ventilator support, length of hospitalization. InSurE and LISA exhibited reduced mortality and decreased risks of moderate to severe BPD, pulmonary hypertension, PVL, and PDA with treatment compared to the Classic group.

Curriculum and assessment tool for less invasive surfactant administration: an international Delphi consensus study

BACKGROUND

Training and assessment of operator competence for the less invasive surfactant administration (LISA) procedure vary. This study aimed to obtain international expert consensus on LISA training (LISA curriculum (LISA-CUR)) and assessment (LISA assessment tool (LISA-AT)).

METHODS

From February to July 2022, an international three-round Delphi process gathered opinions from LISA experts (researchers, curriculum developers, and clinical educators) on a list of items to be included in a LISA-CUR and LISA-AT (Round 1). The experts rated the importance of each item (Round 2). Items supported by more than 80% consensus were included. All experts were asked to approve or reject the final LISA-CUR and LISA-AT (Round 3).

RESULTS

A total of 153 experts from 14 countries participated in Round 1, and the response rate for Rounds 2 and 3 was >80%. Round 1 identified 44 items for LISA-CUR and 22 for LISA-AT. Round 2 excluded 15 items for the LISA-CUR and 7 items for the LISA-AT. Round 3 resulted in a strong consensus (99-100%) for the final 29 items for the LISA-CUR and 15 items for the LISA-AT.

CONCLUSIONS

This Delphi process established an international consensus on a training curriculum and content evidence for the assessment of LISA competence.

IMPACT

This international consensus-based expert statement provides content on a curriculum for the less invasive surfactant administration procedure (LISA-CUR) that may be partnered with existing evidence-based strategies to optimize and standardize LISA training in the future. This international consensus-based expert statement also provides content on an assessment tool for the LISA procedure (LISA-AT) that can help to evaluate competence in LISA operators. The proposed LISA-AT enables standardized, continuous feedback and assessment until achieving proficiency.

Sedation for less invasive surfactant administration in preterm infants: a systematic review and meta-analysis

BACKGROUND

Sedation to preterm neonates receiving less invasive surfactant administration (LISA) for respiratory distress syndrome is controversial.

METHODS

Systematic review and meta-analysis of randomized controlled trials (RCTs) and observational studies (OS) to evaluate the effect of sedative drugs for LISA on respiratory outcomes and adverse effects.

RESULTS

One RCT (78 neonates) and two OS (519 neonates) were analyzed in pairwise meta-analysis and 30 studies (2164 neonates) in proportion-based meta-analysis. Sedative drugs might not affect the duration of the procedure [RCT: mean difference (MD) (95% CI); -11 (-90; 67) s; OS: MD 95% CI: -60 (-178; 58) s; low certainty of evidence (CoE)]. Evidence for success at the first attempt and rescue intubation was uncertain (very low CoE). The risk of nasal intermittent positive pressure ventilation [RCT: 1.97 (1.38-2.81); OS: RR, 95% CI: 2.96 (1.46; 6.00), low CoE], desaturation [RCT: RR, 95% CI: 1.30 (1.03; 1.65), low CoE], and apnea [OS: RR, 95% CI: 3.13 (1.35; 7.24), very low CoE] might be increased with sedation. Bradycardia, hypotension, and mechanical ventilation were comparable between groups (low CoE).

CONCLUSIONS

Use of sedative drugs for LISA temporarily affects the newborn's breathing. Further trials are warranted to explore the use of sedation for LISA.

IMPACT

The effect of sedative drugs (analgesics, sedatives, anesthetics) compared to the effect of no-sedation for LISA in preterm infants with RDS is underexplored. This systematic review and meta-analysis assesses the impact of sedative drugs compared to no-sedation for LISA on short-term pulmonary outcomes and potential adverse events. Sedative drugs for LISA temporarily affect the newborn's breathing (desaturation, apnea) and increase the need for nasal intermittent positive pressure ventilation. For most outcomes, certainty of evidence is low/very low.

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

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

Device positioning with LISA vs. INSURE: a crossover randomized controlled manikin trial

OBJECTIVE

We aimed to compare time of device positioning, success of procedure and operator's opinion with LISA vs. INSURE in a manikin simulating an extremely low birthweight infant.

METHODS

A randomized controlled crossover (AB/BA) trial of surfactant administration with LISA vs. INSURE in a preterm manikin. Forty-two tertiary hospital consultants and pediatric residents with previous experience with LISA and INSURE participated. The primary outcome measure was the time of device positioning. The secondary outcome measures were: success of the first attempt, number of attempts, correct depth, and participant's opinion on difficulty in using the device.

RESULTS

Median time of device positioning was shorter with LISA vs. INSURE (median difference -8 s, 95% confidence interval -16 to -1 s; p = .04). Success at first attempt was 35/40 with LISA (83%) and 31/40 with INSURE (74%) (p = .42). Median number of attempts was 1 (IQR 1-1) with LISA and 1 (IQR 1-2) with INSURE (p = .08). Correct depth was achieved in 30/40 with LISA (71%) and 37/40 with INSURE (88%) (p = .12). Participants found LISA easier to insert in the trachea (p = .002) but INSURE easier to place at the correct depth (p = .008). Handling the device (p = .43), visualizing the glottis (p = .17) and overall difficulty in using the device (p = .13) were not statistically different.

CONCLUSIONS

In a preterm manikin model, positioning a thin catheter (LISA) was quicker and easier than a tracheal tube (INSURE), but the magnitude of the difference was unlikely to be clinically relevant and the tracheal tube was easier to place at the correct depth.

REGISTRATION

clinicaltrial.gov NCT04944108.

New modes of surfactant delivery

The provision of exogenous surfactant to premature infants with respiratory distress syndrome has revolutionized the way we care for these patients, significantly improving survival and decreasing morbidity. Currently, the Intubate-SURfactant-Extubate (INSURE) to non-invasive ventilation method remains the standard method for surfactant delivery in the United States. However, the INSURE method requires intubation via direct visualization with a laryngoscope and possible need for sedation. Both carry significant risk to the patients, prompting the development of less invasive ways of safely and efficaciously providing surfactant to newborn infants. The present article reviews and describes the benefits and limitations of several of these alternative methods, including Less Invasive Surfactant Administration (LISA), Minimally Invasive Surfactant Therapy (MIST), via aerosolization, laryngeal mask airway (LMA), and direct nasopharyngeal deposition, focusing on assessment of clinical benefits and the level/risk of invasiveness.

Should less invasive surfactant administration (LISA) become routine practice in US neonatal units?

The harmful effects of mechanical ventilation (MV) on the preterm lung are well established. Avoiding MV at birth and stabilization on continuous positive airway pressure (CPAP) decreases the composite outcome of death or bronchopulmonary dysplasia. Although preterm infants are increasingly being admitted to the neonatal intensive care unit on CPAP, centers differ in the ability to manage infants primarily on CPAP. Over the last decade, less invasive surfactant administration (LISA), a method of administering surfactant with a thin catheter, has been devised and has been shown to decrease the need for MV and improve outcomes compared to surfactant administration via an endotracheal tube following intubation. While LISA has been widely adopted in Europe and other countries, its use is not widespread in the United States. This article provides a summary of the existing evidence on LISA, and practical guidance for US units choosing to implement a change of practice incorporating optimization of CPAP and LISA. IMPACT: The accumulated body of evidence for less invasive surfactant administration (LISA), a widespread practice in other countries, justifies its use as an alternative to intubation and surfactant administration in US neonatal units. This article summarizes the current evidence for LISA, identifies gaps in knowledge, and offers practical tips for the implementation of LISA as part of a comprehensive non-invasive respiratory support strategy. This article will help neonatal units in the US develop guidelines for LISA, provide optimal respiratory support for infants with respiratory distress syndrome, improve short- and long-term outcomes of preterm infants, and potentially decrease costs of NICU care.

Noninvasive High-Frequency Oscillatory Ventilation vs Nasal Continuous Positive Airway Pressure vs Nasal Intermittent Positive Pressure Ventilation as Postextubation Support for Preterm Neonates in China: A Randomized Clinical Trial

IMPORTANCE

Several respiratory support techniques are available to minimize the use of invasive mechanical ventilation (IMV) in preterm neonates. It is unknown whether noninvasive high-frequency oscillatory ventilation (NHFOV) is more efficacious than nasal continuous positive airway pressure (NCPAP) or nasal intermittent positive pressure ventilation (NIPPV) in preterm neonates after their first extubation.

OBJECTIVE

To test the hypothesis that NHFOV is more efficacious than NCPAP or NIPPV in reducing IMV after extubation and until neonatal intensive care unit discharge among preterm neonates.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter, pathophysiology-based, assessor-blinded, 3-group, randomized clinical trial was conducted in 69 tertiary referral neonatal intensive care units in China, recruiting participants from December 1, 2017, to May 31, 2021. Preterm neonates who were between the gestational age of 25 weeks plus 0 days and 32 weeks plus 6 days and were ready to be extubated were randomized to receive NCPAP, NIPPV or NHFOV. Data were analyzed on an intention-to-treat basis.

INTERVENTIONS

The NCPAP, NIPPV, or NHFOV treatment was initiated after the first extubation and lasted until discharge.

MAIN OUTCOMES AND MEASURES

Primary outcomes were total duration of IMV, need for reintubation, and ventilator-free days. These outcomes were chosen to describe the effect of noninvasive ventilation strategy on the general need for IMV.

RESULTS

A total of 1440 neonates (mean [SD] age at birth, 29.4 [1.8] weeks; 860 boys [59.7%]) were included in the trial. Duration of IMV was longer in NIPPV (mean difference, 1.2; 95% CI, 0.01-2.3 days; P = .04) and NCPAP (mean difference, 1.5 days; 95% CI, 0.3-2.7 days; P = .01) compared with NHFOV. Neonates who were treated with NCPAP needed reintubations more often than those who were treated with NIPPV (risk difference: 8.1%; 95% CI, 2.9%-13.3%; P = .003) and NHFOV (risk difference, 12.5%; 95% CI, 7.5%-17.4%; P < .001). There were fewer ventilator-free days in neonates treated with NCPAP than in those treated with NIPPV (median [25th-75th percentile] difference, -3 [-6 to -1] days; P = .01). There were no differences between secondary efficacy or safety outcomes, except for the use of postnatal corticosteroids (lower in NHFOV than in NCPAP group; risk difference, 7.3%; 95% CI, 2.6%-12%; P = .002), weekly weight gain (higher in NHFOV than in NCPAP group; mean difference, -0.9 g/d; 95% CI, -1.8 to 0 g/d; P = .04), and duration of study intervention (shorter in NHFOV than in NIPPV group; median [25th-75th percentile] difference, -1 [-3 to 0] days; P = .01).

CONCLUSIONS AND RELEVANCE

Results of this trial indicated that NHFOV, if used after extubation and until discharge, slightly reduced the duration of IMV in preterm neonates, and both NHFOV and NIPPV resulted in a lower risk of reintubation than NCPAP. All 3 respiratory support techniques were equally safe for this patient population.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03181958.

Nasal high-frequency oscillatory ventilation versus nasal continuous positive airway pressure as primary respiratory support strategies for respiratory distress syndrome in preterm infants: a systematic review and meta-analysis

Nasal high-frequency oscillatory ventilation (NHFOV) is a new respiratory support strategy despite lacking of enough evidence in preterm infants with respiratory distress syndrome (RDS). The aim of the present systematic review was to explore whether NHFOV reduced the intubation rate as compared with nasal continuous positive airway pressure (NCPAP) as the primary respiratory support strategies in preterm infants with RDS. Medline, the Cochrane library, the Cochrane Controlled Trials Register, EMBASE, Chinese National Knowledge Infrastructure (CNKI), and Wanfang data Information Site were searched from inception to Jan 1, 2021(Prospero2019 CRD42019129316, date and name of registration: Apr 23,2019, The clinical effectiveness of NHFOV vs NCPAP for preterm babies with respiratory distress syndrome). Pooled data from clinically randomized controlled trials (RCTs) comparing NHFOV with NCPAP as the primary respiratory supporting strategies in preterm infants with RDS were performed using the fixed-effects models whenever no heterogeneity was shown. The primary outcome was intubation rate. Four randomized controlled trials involving 570 participants were included. Comparing with NCPAP, NHFOV resulted in less intubation (relative risk (RR) 0.44; 95% confidence interval (CI) 0.29-0.67, P = 0.0002), and heterogeneity was not found among the trials in the fixed-effects model (P = 0.78, I² = 0%). Similar result also appeared in sensitivity analysis after excluding one study with significant difference (RR 0.44; 95% CI 0.25-0.78, P = 0.005) (P = 0.58, I² = 0%).Conclusion: NHFOV decreased the intubation rate as compared with NCPAP as primary respiratory supporting strategies in preterm infants suffering from RDS. Future research should assess whether NHFOV can reduce the incidence of bronchopulmonary dysplasia (BPD) and intubation rate in preterm infants with BPD. Fund by Natural Science Foundation of Chongqing (cstc2020jcyj-msxmX0197), and "guan'ai" preterm Study Program of Renze Foundation of Beijing(K022). What is Known: • Nasal high-frequency oscillatory ventilation (NHFOV) has been described to be another advanced version of nasal continuous positive airway pressure (NCPAP). However, its beneficial effects among different studies as the primary modes in the early life of preterm infants with respiratory distress syndrome (RDS) were inconsistent. What is New: • Comparing with NCPAP, NHFOV decreases the risk of intubation as a primary respiratory supporting strategy in early life for preterm infants suffering from RDS.

Enhanced INSURE (ENSURE): an updated and standardised reference for surfactant administration

There is no firm consensus about the optimal technique for the administration of exogenous surfactant in preterm neonates, and different techniques may be equally effective. The intubation-surfactant-extubation (INSURE) procedure has not been fully described, and important details, such as duration and mode of ventilation, remain unclear, leading to significant clinical practice variations and influencing its suitability and feasibility. Since the first INSURE description, our knowledge in respiratory care has largely progressed, but the technique has not been updated according to current evidence-based practice. Thus, our aim is to formally describe a modern way to perform INSURE, based on the current knowledge and technology, to increase its feasibility and patients' safety. We offer ENSURE (Enhanced INSURE) as an updated and standardised technique for surfactant administration, clarifying crucial issues of the original method by applying current state-of-the-art concepts of respiratory care. We performed a cross-sectional observational study enrolling 57 preterm neonates describing ENSURE feasibility and safety.   Conclusion: ENSURE can be used as a reference technique in clinical practice, teaching and research. What is Known: • There is no consensus about the optimal method for surfactant administration. INSURE technique has been originally described many years ago without considering modern principles of neonatal respiratory care and the available state-of-the-art technology. What is New: • We here describe a modern way to perform INSURE, based on the current knowledge and technology. We called it ENSURE (Enhanced INSURE) and clarified crucial points of the original technique, in light of the current knowledge. We verified feasibility and safety of ENSURE in a cross-sectional observational study enrolling 57 preterm neonates.

Improved Less Invasive Surfactant Administration Success in Preterm Infants after Procedure Standardization

Less invasive surfactant administration (LISA) has been introduced at our tertiary Level IV perinatal center since 2016 with an unsatisfactory success rate, which we attributed to an inconsistent, non-standardized approach and ambiguous patient inclusion criteria. This study aimed to improve the LISA success rate to at least 75% within 12 months by implementing a highly standardized LISA approach combined with team training. The Plan Do Study Act method of quality improvement was used for this initiative. Baseline assessment included a review of patient medical records 12 months before the intervention regarding patient characteristics, method success rate, respiratory, and adverse outcomes. A multi-professional team developed a standardized LISA approach and a training program including an educational film, checklists, pocket cards, and team briefings. Twenty-one preterm infants received LISA before and 24 after the intervention. The mean LISA success rate improved from 62% before the intervention to 92% (p = 0.029) after the intervention. Implementing a highly standardized LISA approach and multi-professional team training significantly improved the methods’ success rate.

Techniques to evaluate surfactant activity for a personalized therapy of RDS neonates

According to both European and American Guidelines, preterm neonates have to be treated by nasal continuous air pressure (CPAP) early in the delivery room. The administration of surfactant should be reserved only for babies with respiratory distress syndrome (RDS) with increased oxygen requirement, according to different thresholds of FiO₂. However, these oxygenation thresholds do not fully take into consideration the lung physiopathology and mechanics or the lung surfactant biology of RDS neonates. Since surfactant replacement therapy (SRT) seems to be more effective if it is initiated within the first 3 hours after birth, the use of a reliable bench-to-bedside biological test able to predict as soon as possible the necessity of SRT will help optimise individualised therapies and personalise the actual collective strategy used to treat RDS neonates. With this in mind, in the present review several quantitative and qualitative biological tests to assess the surfactant status in RDS neonates are introduced as potential candidates for the early prediction of SRT requirement, summarising the state-of-the-art in the evaluation of surfactant activity.

Surfactant Administration Through Laryngeal or Supraglottic Airways

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

Premedication with ketamine or propofol for less invasive surfactant administration (LISA): observational study in the delivery room

Less invasive surfactant administration (LISA) has become increasingly popular in neonatal intensive care units (NICUs), but there are currently no guidelines for the premedication prior to this procedure. The aim of this observational study was to compare the efficacy and tolerance of intravenous administrations of ketamine and propofol before LISA in neonates born before 30 weeks of gestational age (GA). The primary outcome was requirement of intubation within 2 h of the procedure. One hundred and fourteen infants, with respective GA and birthweight of 27.6 (26.4, 28.7) weeks and 940 (805, 1140) g, were prospectively included from January 2016 to December 2019. Drug doses were 1 (0.5, 1) mg/kg for ketamine and 1 (1, 1.9) mg/kg for propofol, providing comparable comfort during LISA (p = 0.61). Rates of intubation within 2 h were 5/52 after ketamine, and 5/62 after propofol [aOR 0.54 (0.11-2.68)]. No difference was observed for rates of intubation at 24 h and 72 h following LISA, mortality, or severe morbidity.Conclusion: Pending results from prospective trials, these findings suggest that ketamine or propofol can be used for premedication before LISA, as they show comparable efficacy and tolerance.Trial registration: This study was recorded on the National Library of Medicine registry (https:// clinicaltrials.gov / Identifier: NCT03705468). What is Known? • Less invasive surfactant administration (LISA) is increasingly used in spontaneously breathing premature infants supported with continuous positive airway pressure, but few data are available to guide adequate premedication for this procedure. What is New? • This observational study of 114 neonates, all less than 30-week gestational age and requiring surfactant without endotracheal tube in the delivery room, suggested that ketamine or propofol can be used for premedication before LISA with comparable efficacy and tolerance.

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.

Respiratory distress syndrome in preterm neonates in the era of precision medicine: A modern critical care-based approach

Respiratory distress syndrome (RDS) was recognized to be caused by primary surfactant deficiency almost 70 years ago and continuous positive airway pressure was introduced approximately 50 years ago. Since then, there have been many developments in neonatology; we know many things but others are still controversial. The more we know, the more questions arise. However, this review aims to indicate what is more needed to understand and how should be the modern approach to RDS in the era of precision medicine. The review is divided between new concepts and new tools. We will explain the interaction between steroids, CPAP and surfactant, as well as the surfactant catabolism and the diagnosis of NARDS; lung ultrasound and new tools to optimize CPAP will also be covered. How these concepts are integrated in the author's personal experience is also illustrated.

Surfactant lung delivery with LISA and InSurE in adult rabbits with respiratory distress

BACKGROUND

In preterm infants, InSurE (Intubation-Surfactant-Extubation) and LISA (less invasive surfactant administration) techniques allow for exogenous surfactant administration while reducing lung injury associated with mechanical ventilation. We compared the acute pulmonary response and lung deposition of surfactant by LISA and InSurE in surfactant-depleted adult rabbits.

METHODS

Twenty-six spontaneously breathing surfactant-depleted adult rabbits (6-7 weeks old) with moderate RDS and managed with nasal continuous positive airway pressure were randomized to 3 groups: (1) 200 mg/kg of surfactant by InSurE; (2) 200 mg/kg of surfactant by LISA; (3) no surfactant treatment (Control). Gas exchange and lung mechanics were monitored for 180 min. After that, surfactant lung deposition and distribution were evaluated monitoring disaturated-phosphatidylcholine (DSPC) and surfactant protein C (SP-C), respectively.

RESULTS

No signs of recovery were found in the untreated animals. After InSurE, oxygenation improved more rapidly compared to LISA. However, at 180' LISA and InSurE showed comparable outcomes in terms of gas exchange, ventilation parameters, and lung mechanics. Neither DSPC in the alveolar pool nor SP-C signal distributions in a frontal lung section were significantly different between InSurE and LISA groups.

CONCLUSIONS

In an acute setting, LISA demonstrated efficacy and surfactant lung delivery similar to that of InSurE in surfactant-depleted adult rabbits.

IMPACT

Although LISA technique is gaining popularity, there are still several questions to address. This is the first study comparing LISA and InSurE in terms of gas exchange, ventilation parameters, and lung mechanics as well as surfactant deposition and distribution. In our animal study, three hours post-treatment, LISA method seems to be as effective as InSurE and showed similar surfactant lung delivery. Our findings provide some clarifications on a fair comparison between LISA and InSurE techniques, particularly in terms of surfactant delivery. They should reassure some of the concerns raised by the clinical community on LISA adoption in neonatal units.

Premedication practices for less invasive surfactant administration - results from a nationwide cohort study

BACKGROUND AND AIMS

There are no established premedication schemes for less invasive surfactant administration (LISA) in neonatal RDS. The aim was to describe "real-world" practices and to assess the safety of premedication and its impact on the technical ease of the LISA procedure.

METHODS

Data from the prospective LISA cohort study conducted in 31 tertiary neonatal units were evaluated for premedication practices. Infants who received analgesics and/or sedatives before LISA and those receiving non-pharmacological sedation with sublingual 30% glucose were compared versus nonpremedicated neonates, acting as a reference. Safety of premedication was assessed with the rate of adverse events during LISA, changes in oxygenation status, the need for rescue intubation, and mechanical ventilation in the first 24 h of life. Ease of conducting LISA was an efficacy endpoint.

RESULTS

Of 500 enrolled newborns, 102 (20.4%) received premedication for LISA; 88 infants were given analgesics/sedatives and 14 sublingual glucose. Pharmacological sedation was most often performed with ketamine (51/88; 57.9%), midazolam (16/88; 18.2%) and propofol (8/88; 1.6%). Compared to non-premedication, the use of analgesics/sedatives was associated with a significant increase in the rate of apnea (9.1 vs 2.6%; p = 0.009) and a significantly higher decrease in SpO₂/FiO₂ (-55 ± 62 vs -32 ± 50; p < 0.001). However, the rates of rescue intubation and the need for early mechanical ventilation were not significantly different. Sedation with glucose did not affect the frequency of adverse events. LISA procedures had a similar level of ease regardless of the premedication used and were rated as easy or very easy in 69% of non-premedicated infants, 65.9% of the analgesics/sedatives group and 78.5% of the glucose group (p = ns).

CONCLUSION

Analgesics/sedatives prior to LISA increased the rate of apnea and decreased blood oxygenation but did not lead to tracheal intubation and early mechanical ventilation. Trials addressing the impact on LISA-related stress are necessary to determine the ultimate usefulness of premedication.

Systematic review found that using thin catheters to deliver surfactant to preterm neonates was associated with reduced bronchopulmonary dysplasia and mechanical ventilation

AIM

Surfactant delivery is a cornerstone for managing respiratory distress in preterm neonates, but data on the best surfactant delivery methods have been conflicting.

METHODS

A systematic literature review using the PubMed, Embase, Cochrane Library and Web of Science databases identified papers published up to November 5, 2019. Additional studies were identified from trial registries, conference proceedings and the reference lists of the selected papers.

RESULTS

We identified 15 studies covering 4926 preterm infants. The randomised controlled trials (RCTs) and observational studies both showed significant reductions in early intubation rates with use of thin catheters. The relative risk (RR) was 0.63 and the 95% confidence interval (95% CI) was 0.55-0.72 (P < .01), with an odds ratio (OR) of 0.40 and 95% CI of 0.35-0.45 (P < .0001). The collective results from the RCTs revealed a significant decrease in bronchopulmonary dysplasia (BPD) rates in the thin catheter group (RR, 0.47; 95% CI 0.33-0.66; P < .01). These findings were consistent with the observational studies (OR 0.47; 95% CI 0.43-0.52; P < .01).

CONCLUSION

Using thin catheters to deliver surfactant in comparison with intubate-surfactant-extubate (INSURE) to newborn preterm infants with respiratory distress was associated with a reduced incidence of BPD and less need for mechanical ventilation.

Surfactant Injury in the Early Phase of Severe Meconium Aspiration Syndrome

No in vivo data are available regarding the effect of meconium on human surfactant in the early stages of severe meconium aspiration syndrome (MAS). In the present study, we sought to characterize the changes in surfactant composition, function, and structure during the early phase of meconium injury. We designed a translational prospective cohort study of nonbronchoscopic BAL of neonates with severe MAS (n = 14) or no lung disease (n = 18). Surfactant lipids were analyzed by liquid chromatography-high-resolution mass spectrometry. Secretory phospholipase A₂ subtypes IB, V, and X and SP-A (surfactant protein A) were assayed by ELISA. SP-B and SP-C were analyzed by Western blotting under both nonreducing and reducing conditions. Surfactant function was assessed by adsorption test and captive bubble surfactometry, and lung aeration was evaluated by semiquantitative lung ultrasound. Surfactant nanostructure was studied using cryo-EM and atomic force microscopy. Several changes in phospholipid subclasses were detected during MAS. Lysophosphatidylcholine species released by phospholipase A₂ hydrolysis were increased. SP-B and SP-C were significantly increased together with some shorter immature forms of SP-B. Surfactant function was impaired and correlated with poor lung aeration. Surfactant nanostructure was significantly damaged in terms of vesicle size, tridimensional complexity, and compactness. Various alterations of surfactant phospholipids and proteins were detected in the early phase of severe meconium aspiration and were due to hydrolysis and inflammation and a defensive response. This impairs both surfactant structure and function, finally resulting in reduced lung aeration. These findings support the development of new surfactant protection and antiinflammatory strategies for severe MAS.

Minimally invasive surfactant therapy versus InSurE in preterm neonates of 28 to 34 weeks with respiratory distress syndrome on non-invasive positive pressure ventilation-a randomized controlled trial

Preterm neonates with respiratory distress syndrome (RDS) are commonly treated with surfactant by intubate surfactant extubate (InSurE) technique. Mode of surfactant administration has evolved towards less invasive technique in the last few years. We randomised 58 preterm infants of 28-34 weeks of gestation with RDS within 6 h of birth to receive surfactant by InSurE or minimally invasive surfactant therapy (MIST). Non-invasive positive pressure ventilation (NIPPV) was used as primary respiratory support. The main objective was to compare the need of invasive mechanical ventilation (IMV) in first 72 h of life and secondarily hemodynamically significant patent ductus arteriosus (hsPDA), intraventricular haemorrhage (IVH) (> grade 2), bronchopulmonary dysplasia (BPD) and composite outcome of BPD/mortality. We did not find any difference in need of IMV in first 72 h between MIST and InSurE (relative risk with MIST, 0.62; 95% confidence interval, 0.22 to 1.32). No difference was observed in terms of hs PDA, IVH (> grade 2), BPD and composite outcome of BPD/mortality.Conclusion: There is no difference between MIST and InSurE in preterm neonates with RDS with NIPPV as a primary mode of respiratory support. Larger multicentre studies are needed to further explore differences in treatment failure and other secondary outcomes.Trial registration: www.ctri.nic.in id CTRI/2019/03/017992, registration date March 8, 2019. What is Known • InSurE is commonly used for many years for treatment of RDS in preterm neonates. • MIST has been introduced as a newer tool. What is New • MIST with feeding tube is comparable with InSurE in preterm infants with RDS in developing countries. •NIPPV can be used as primary respiratory support for MIST.

Effect of a new respiratory care bundle on bronchopulmonary dysplasia in preterm neonates

The development of devices that can fix the tidal volume in high-frequency oscillatory ventilation (HFOV) has allowed for a significant improvement in the management of HFOV. At our institution, this had led to the earlier use of HFOV and promoted a change in the treatment strategy involving the use of higher frequencies (above 15 Hz) and lower high-frequency tidal volumes (VThf). The purpose of this observational study was to assess how survival without bronchopulmonary dysplasia grades 2 and 3 (SF-BPD) is influenced by these modifications in the respiratory strategy applied to preterm infants (gestational age < 32 weeks at birth) who required mechanical ventilation (MV) in the first 3 days of life. We compared a baseline period (2012-2013) against a period in which this strategy had been fully implemented (2016-2017). A total of 182 patients were exposed to MV in the first 3 days of life being a higher proportion on HFOV at day 3 in the second period 79.5% (n 35) in 2016-2017 vs 55.4% (n 31) in 2012-2013. After adjusting for perinatal risk factors, the second period is associated with an increased rate of SF-BPD (OR 2.28; CI 95% 1.072-4.878); this effect is more evident in neonates born at a gestational age of less than 29 weeks (OR 4.87; 95% CI 1.9-12.48).Conclusions : The early use of HFOV combined with the use of higher frequencies and very low VT was associated with an increase in the study population's SF-BPD. What is Known: • High-frequency ventilation with volume guarantee improve ventilation stability and has been shown to reduce lung damage in animal models. What is New: • The strategy of an earlier use of high-frequency oscillatory ventilation combined with the use of higher frequencies and lower tidal volume is associated to an increase in survival without bronchopulmonary dysplasia in our population of preterm infants.