Respiratory distress syndrome in preterm infants of less than 32 weeks: What difference does giving 100 or 200 mg/kg of exogenous surfactant make?

Impact of implementation of 2019 European respiratory distress syndrome guidelines on bronchopulmonary dysplasia in very preterm infants

BACKGROUND

To evaluate the impact of implementation of 2019 European respiratory distress syndrome (RDS) guidelines on the incidence of bronchopulmonary dysplasia (BPD).

METHOD

We retrospectively collected the clinical data of very preterm infants (VPIs) born before 32 gestational weeks from January 1st 2018 to December 31st 2021. VPIs were divided into group A and group B according to their birth date which was before or at/after January 1st 2020, when the 2019 European RDS guidelines were introduced. BPD is considered as primary outcome. We statistically analyzed all the data, and we compared the general characteristics, ventilation support, medication, nutrition and the outcomes between the two groups.

RESULTS

A total of 593 VPIs were enrolled, including 380 cases in group A and 213 cases in group B. There were no statistic differences regarding to gender ratio, gestational age, birth weight and delivery mode between the two groups. Compared with group A, group B showed higher rate of antenatal corticosteroid therapy (75.1% vs. 65.5%). The improvement of ventilation management in these latter patients included lower rate of invasive ventilation (40.4% vs. 50.0%), higher rate of volume guarantee (69.8% vs. 15.3%), higher positive end expiratory pressure (PEEP) [6 (5, 6) vs. 5 (5, 5) cmH2O] and higher rate of synchronized nasal intermittent positive pressure ventilation (sNIPPV) (36.2% vs. 5.6%). Compared with group A, group B received higher initial dose of pulmonary surfactant [200 (160, 200) vs. 170 (130, 200) mg/Kg], shorter antibiotic exposure time [13 (7, 23) vs. 17 (9, 33) days], more breast milk (86.4% vs. 70.3%) and earlier medication for hemodynamically significant patent ductus arteriosus (hsPDA) treatment [3 (3, 4) vs. 8 (4, 11) days] (p < 0.05). As the primary outcome, the incidence of BPD was significantly decreased (16.9% vs. 24.2%) (p < 0.05), along with lower extrauterine growth retardation (EUGR) rate (39.0% vs. 59.7%), while there were no statistic differences regarding to other secondary outcomes, including mortality, intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), retinopathy of preterm (ROP) and necrotizing enterocolitis (NEC). However, in the subgroups of infants less than 28 gestational weeks or infants less than 1,000 g, the incidence of BPD was not significantly decreased (p > 0.05).

CONCLUSIONS

After implementation of 2019 European RDS guidelines, the overall incidence of BPD was significantly decreased in VPIs. Continuous quality improvement is still needed in order to decrease the incidence of BPD in smaller infants who are less than 28 gestational weeks or less than 1,000 g.

Less Invasive Surfactant Administration for Preterm Infants - State of the Art

BACKGROUND

Less invasive surfactant administration (LISA) has become the preferred method of surfactant administration for spontaneously breathing babies on continuous positive airway pressure (CPAP).

SUMMARY

The development of LISA followed the need to combine CPAP and surfactant replacement as mainstay treatment options for respiratory distress syndrome, thereby avoided exposure to positive pressure ventilation.

KEY MESSAGES

This review summarises the current knowns and unknowns of LISA including the physiological concept, its relevance for short-term and long-term outcomes and the challenges for practical implementation of LISA as part of a less invasive respiratory care bundle. Further, we provide an update of the evidence on alternatives to LISA, for example, nebulised surfactant administration, pharyngeal deposition of surfactant and delivery via supraglottic airway.

Comparison of porcine versus bovine surfactant in preterm respiratory distress syndrome: Evidence from real-world data. A multicentre collaboration from Karnataka

BACKGROUND & OBJECTIVES

Porcine surfactant (200 mg/kg initial dose) seems to be superior to bovine surfactants (100 mg/kg) in respiratory distress syndrome (RDS). There is limited data on the choice of surfactant from the developing world. Logically, using higher doses of porcine surfactant comes with an additional cost burden. We decided to evaluate the clinical effects of different types of surfactants.

METHODS

A retrospective analysis was conducted from August 2019 to December 2022 in six tertiary centers. Neonates 24-34 weeks of gestation with RDS requiring either porcine (200 mg/kg) or bovine surfactant (100 mg/kg) were enrolled. The proportion of BPD, redosing, and other morbidities in either group were analyzed. The outcomes in preterm ≥28 and <28 weeks subgroups were analyzed.

RESULTS

Of 1149 eligible babies, 302 (26%) received surfactant after stabilization with CPAP. One hundred fifty-eight received porcine, and 144 received bovine surfactant. There was a higher BPD in porcine compared to the bovine group on univariate analysis [24 (15%) vs. 6 (4%); OR: 4; 95% CI: 1.6-10; p = 0.002]. On logistic regression, the gestational age and PDA requiring treatment were independent predictors of BPD, and the type of surfactant and centres did not influence BPD. Redosing [27 (17%) vs. 18 (12%), OR: 1.4; 95% CI: 0.7-2.7; p = 0.2] was not different between both surfactant types. Other morbidities like mortality, air leaks, invasive ventilation, and CPAP duration were also not different between the groups.

CONCLUSION

We could not find a difference in the outcomes of BPD and redosing using porcine surfactant at 200 mg/kg compared to bovine surfactant. Considering the cost burden in the developing world, efficacy needs to be evaluated in randomized clinical trials.

Reduced pulmonary oxygen diffusion at 36 weeks of postmenstrual age in small-for-gestational-age preterm infants of less than 32 weeks without bronchopulmonary dysplasia

BACKGROUND

Small-for-gestational-age (SGA) preterm infants are at increased risk of developing bronchopulmonary dysplasia (BPD). There is limited information on pulmonary oxygen diffusion of SGA preterm infants, particularly in those without BPD.

OBJECTIVE

To compare the pulmonary oxygen diffusion of SGA to that of appropriate-for-gestational-age (AGA) preterm infants without BPD.

STUDY DESIGN

Preterm infants with a gestational age (GA) between 24.0 and 31.6 weeks were studied. The oxygen saturation (SpO2 ), fraction to inspired oxygen (FiO2 ), and the SpO2 to FiO2 ratio (SFR) were compared between SGA and AGA infants. The association between SGA and SFR at 36 weeks was assessed using a multiple regression analysis. In the subgroup without BPD, SGA were match-paired for GA and gender with AGA infants.

RESULTS

We analyzed 1189 infants surviving at 36 weeks: 194 (16%) were SGA and 995 (84%) AGA. The incidence of BPD was significantly higher in SGA than AGA infants (32% vs. 13%; p = .000). Out of the 995 infants without BPD, 132 (13%) were SGA and 863 (87%) AGA. SGA was negatively associated with the SFR value at 36 weeks, independently from BPD. SGA infants without BPD had significantly higher (better) SFR at birth, but lower (worse) SpO2 and SFR and from 33 to 36 weeks than their matched AGA counterpart. At 36 weeks, median SpO2 and SFR values were 97.7 versus 98.4 (p = .006) and 465 versus 468 (p = .010) in match-paired SGA and AGA, respectively.

CONCLUSION

Among preterm infants of less than 32 weeks and without BPD, SGA infants had a reduced pulmonary oxygen diffusion at 36 weeks in comparison with AGA infants.

Who Needs a Second Dose of Exogenous Surfactant?

OBJECTIVE

To identify prenatal and postnatal risk factors associated with surfactant redosing.

STUDY DESIGN

Retrospective, single-regional center study including all infants born from 24 + 0 to 31 + 6 weeks of gestation in the Marche Region, Italy, and admitted to a single level III regional NICU from January 1, 2004, to February 28, 2021. Clinical factors associated with surfactant redosing were identified through logistic regression analysis.

RESULTS

Of 1615 consecutive admissions, 662 infants were treated with exogenous surfactant: 462 (70%) received a single dose and 200 (30%) received more than 1 dose (25.5% two doses and 4.5% three doses). Risk of redosing was higher for infants born to mothers with hypertension in pregnancy (OR 3.95, P < .001), for small for gestational age (SGA) infants (OR 3.93, P < .001) and when the first surfactant dose was 100 mg/kg instead of 200 mg/kg (OR 4.56/4.61, P < .001). Infants with greater GA, delayed first surfactant administration, and milder respiratory distress syndrome had reduced risk of redosing. Infants who required multiple surfactant doses had a higher rate of bronchopulmonary dysplasia and mortality, as well as longer duration of respiratory support than patients that received 1 dose.

CONCLUSIONS

Hypertension in pregnancy and SGA status were found to be statistically and clinically significant predictors of surfactant redosing. Understanding the pathophysiology of these conditions requires further investigation.

Exogenous surfactant reduces inflammation and redox imbalance in rats under prone or supine mechanical ventilation

Mechanical ventilation (MV) is a lifesaving therapy for patients with acute or chronic respiratory failure. Despite, it can also cause lung injury by inducing or worsening inflammatory responses and oxidative stress. Several clinical approaches have protective effects on the lungs, including the prone position and exogenous surfactant; however, few studies have evaluated the association between the two strategies, especially in individuals without previous lung injury. We tested the hypothesis that the effects of the homogenization in lung aeration caused by the prone position in association with the anti-inflammatory properties of exogenous surfactant pre-treatment could have a cumulative protective effect against ventilator-induced lung injury. Therefore, Wistar rats were divided into four experimental groups: Mechanical Ventilation in Supine Position (MVSP), Mechanical Ventilation in Prone position (MVPP), Mechanical Ventilation in Supine Position + surfactant (MVSPS), and Mechanical Ventilation in Prone Position + Surfactant (MVPPS). The intranasal instillation of a porcine surfactant (Curosurf®) was performed in the animals of MVSPS and MVPPS 1 h before the MV, all the rats were subjected to MV for 1 h. The prone position in association with surfactant decreased mRNA expression levels of pro-inflammatory cytokines in ventilated animals compared to the supine position; in addition, the NfκB was lower in MVPP, MVSPS and MVPPS when compared to MVSP. However, it had no effects on oxidative stress caused by MV. Pre-treatment with exogenous surfactant was more efficient in promoting lung protection than the prone position, as it also reduced oxidative damage in the lung parenchyma. Nevertheless, the surfactant did not cause additional improvements in most parameters that were also improved by the prone position. Our results indicate that the pre-treatment with exogenous surfactant, regardless of the position adopted in mechanical ventilation, preserves the original lung histoarchitecture, reduces redox imbalance, and reduces acute inflammatory responses caused by mechanical ventilation in healthy adult Wistar rats.

Use of budesonide associated with a pulmonary surfactant to prevent bronchopulmonary dysplasia in premature newborns - A systematic review

OBJECTIVE

Among the mechanisms proposed for the development of bronchopulmonary dysplasia is the increase in the pulmonary inflammatory process and oxidative stress. Thus, the control of this process may result in improvements in bronchopulmonary dysplasia-related outcomes. This study aims to analyze the current scientific evidence regarding the use of budesonide, a potent anti-inflammatory drug, associated with a pulmonary surfactant to prevent bronchopulmonary dysplasia.

METHODS

A systematic review of the literature was performed on the Embase and MEDLINE platforms, and studies that compared budesonide with pulmonary surfactant versus pulmonary surfactant for treating respiratory distress syndrome were included. The primary outcome was a reduction in bronchopulmonary dysplasia or death.

RESULTS

Four randomized clinical trials and two observational studies were included in this systematic review. Three of the randomized clinical trials found a reduction in bronchopulmonary dysplasia or death in the use of budesonide with the surfactant, all the other studies (1 clinical trial and 2 observational studies) found no statistical differences between the groups for the primary outcomes. The three main studies showed a reduction in the primary outcome; however, all studies showed great heterogeneity regarding the type of surfactant (poractant or beractant) and the method of administration.

CONCLUSION

Robust clinical studies, in a heterogeneous population, using porcine surfactant associated with budesonide, with administration by a minimally invasive technique are necessary for there to be a recommendation based on scientific evidence for its widespread use.

European Consensus Guidelines on the Management of Respiratory Distress Syndrome: 2022 Update

Respiratory distress syndrome (RDS) care pathways evolve slowly as new evidence emerges. We report the sixth version of "European Guidelines for the Management of RDS" by a panel of experienced European neonatologists and an expert perinatal obstetrician based on available literature up to end of 2022. Optimising outcome for babies with RDS includes prediction of risk of preterm delivery, appropriate maternal transfer to a perinatal centre, and appropriate and timely use of antenatal steroids. Evidence-based lung-protective management includes initiation of non-invasive respiratory support from birth, judicious use of oxygen, early surfactant administration, caffeine therapy, and avoidance of intubation and mechanical ventilation where possible. Methods of ongoing non-invasive respiratory support have been further refined and may help reduce chronic lung disease. As technology for delivering mechanical ventilation improves, the risk of causing lung injury should decrease, although minimising time spent on mechanical ventilation by targeted use of postnatal corticosteroids remains essential. The general care of infants with RDS is also reviewed, including emphasis on appropriate cardiovascular support and judicious use of antibiotics as being important determinants of best outcome. We would like to dedicate this guideline to the memory of Professor Henry Halliday who died on November 12, 2022.These updated guidelines contain evidence from recent Cochrane reviews and medical literature since 2019. Strength of evidence supporting recommendations has been evaluated using the GRADE system. There are changes to some of the previous recommendations as well as some changes to the strength of evidence supporting recommendations that have not changed. This guideline has been endorsed by the European Society for Paediatric Research (ESPR) and the Union of European Neonatal and Perinatal Societies (UENPS).

Surfactant Replacement Therapy: What’s the New Future?

Surfactant replacement therapy (SRT) can be lifesaving for preterm babies with respiratory distress because of surfactant deficiency. Attempts have been made over the last two decades to make surfactant administration as smooth and as nontraumatic as possible. Lesser invasive techniques, such as less invasive surfactant administration, minimally invasive surfactant therapy, intrapartum pharyngeal surfactant therapy, and the laryngeal mask airway, are preferred over invasive techniques like intubate surfactant extubation to reduce trauma and peridosing adverse effects. However, at present, aerosolized surfactant (AS) via nebulization remains the only truly noninvasive method of SRT. Many animal and human studies have shown promising results with the use of AS with similar clinical effects to an instilled surfactant with greater safety potential. But still AS has not been adapted to routine neonatal care. There is still scope for studies to further strengthen the role of AS. Also, SRT is a constantly changing field with new innovations revolutionizing and replacing old techniques.