Two-Year Outcomes After Minimally Invasive Surfactant Therapy in Preterm Infants: Follow-Up of the OPTIMIST-A Randomized Clinical Trial

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-invasive versus invasive respiratory support in preterm infants

Respiratory insufficiency is almost ubiquitous in infants born preterm, with its incidence increasing with lower gestational age. A wide range of respiratory support management strategies are available for these infants, separable into non-invasive and invasive forms of respiratory support. Here we review the history and evolution of respiratory care for the preterm infant and then examine evidence that has emerged to support a non-invasive approach to respiratory management where able. Continuous positive airway pressure (CPAP) is the non-invasive respiratory support mode currently with the most evidence for benefit. CPAP can be delivered safely and effectively and can commence in the delivery room. Particularly in early life, time spent on non-invasive respiratory support, avoiding intubation and mechanical ventilation, affords benefit for the preterm infant by virtue of a lessening of lung injury and hence a reduction in incidence of bronchopulmonary dysplasia. In recent years, enthusiasm for application of non-invasive support has been further bolstered by new techniques for administration of exogenous surfactant. Methods of less invasive surfactant delivery, in particular with a thin catheter, have allowed neonatologists to administer surfactant without resort to endotracheal intubation. The benefits of this approach appear to be sustained, even in those infants subsequently requiring mechanical ventilation. This cements the notion that any reduction in exposure to mechanical ventilation leads to alleviation of injury to the vulnerable preterm lung, with a long-lasting effect. Despite the clear advantages of non-invasive respiratory support, there will continue to be a role for intubation and mechanical ventilation in some preterm infants, particularly for those born <25 weeks' gestation. It is currently unclear what role early non-invasive support has in this special population, with more studies required.

Coffee to Make LISA-a-go

In August of 1963, Patrick Bouvier Kennedy, the fourth child of Jackie Onassis Kennedy and John F. Kennedy, died less than 48 hours after his birth from respiratory distress syndrome (RDS) of the newborn. His tragic death inspired research into the physiology of RDS, one product of which was the development of surfactant replacement therapies which have saved millions of neonates from a similar fate. Shortly after the demonstration of its efficacy in 1980, exogenous surfactant replacement therapy became the mainstay intervention for RDS.1 Exogenous surfactant was originally administered via an endotracheal tube in mechanically ventilated neonates, a practice which may lead to ventilator-induced injury to the immature lung.

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.

Statistical Significance Versus Clinical Relevance: A Head-to-Head Comparison of the Fragility Index and Relative Risk Index

Background In biostatistics, assessing the fragility of research findings is crucial for understanding their clinical significance. This study focuses on the fragility index, unit fragility index, and relative risk index as measures to evaluate statistical fragility. The fragility indices assess the susceptibility of p-values to change significance with minor alterations in outcomes within a 2x2 contingency table. In contrast, the relative risk index quantifies the deviation of observed findings from therapeutic equivalence, the point at which the relative risk equals 1. While the fragility indices have intuitive appeal and have been widely applied, their behavior across a wide range of contingency tables has not been rigorously evaluated. Methods Using a Python software program, a simulation approach was employed to generate random 2x2 contingency tables. All tables under consideration exhibited p-values < 0.05 according to Fisher's exact test. Subsequently, the fragility indices and the relative risk index were calculated. To account for sample size variations, the indices were divided by the sample size to give fragility and risk quotients. A correlation matrix assessed the collinearity between each metric and the p-value. Results The analysis included 2,000 contingency tables with cell counts ranging from 20 to 480. Notably, the formulas for calculating the fragility indices encountered limitations when cell counts approached zero or duplicate cell counts hindered standardized application. The correlation coefficients with p-values were as follows: unit fragility index (-0.806), fragility index (-0.802), fragility quotient (-0.715), unit fragility quotient (-0.695), relative risk index (-0.403), and risk quotient (-0.261). Conclusion The fragility indices and fragility quotients demonstrated a strong correlation with p-values below 0.05, while the relative risk index and relative risk quotient exhibited a weak association with p-values below this threshold. This implies that the fragility indices offer limited additional information beyond the p-value alone. In contrast, the relative risk index and risk quotient exhibit independence from the p-value, indicating that they may provide important additional information about statistical fragility by evaluating the divergence of observed results from therapeutic equivalence, irrespective of the p-value-based statistical significance.