Ventilator-induced lung injury in preterm infants

The influence of chorioamnionitis on respiratory drive and spontaneous breathing of premature infants at birth: a narrative review

Most very premature infants breathe at birth but require respiratory support in order to stimulate and support their breathing. A significant proportion of premature infants are affected by chorioamnionitis, defined as an umbrella term for antenatal inflammation of the foetal membranes and umbilical vessels. Chorioamnionitis produces inflammatory mediators that potentially depress the respiratory drive generated in the brainstem. Such respiratory depression could maintain itself by delaying lung aeration, hampering respiratory support at birth and putting infants at risk of hypoxic injury. This inflammatory-mediated respiratory depression may contribute to an association between chorioamnionitis and increased requirement of neonatal resuscitation in premature infants at birth. This narrative review summarises mechanisms on how respiratory drive and spontaneous breathing could be influenced by chorioamnionitis and provides possible interventions to stimulate spontaneous breathing.  Conclusion: Chorioamnionitis could possibly depress respiratory drive and spontaneous breathing in premature infants at birth. Interventions to stimulate spontaneous breathing could therefore be valuable. What is Known: • A large proportion of premature infants are affected by chorioamnionitis, antenatal inflammation of the foetal membranes and umbilical vessels. What is New: • Premature infants affected by chorioamnionitis might be exposed to higher concentrations of respiratory drive inhibitors which could depress breathing at birth. • Premature infants affected by chorioamnionitis seem to be associated with a higher and more extensive requirement of resuscitation at birth.

A comprehensive study on machine learning models combining with oversampling for bronchopulmonary dysplasia-associated pulmonary hypertension in very preterm infants

BACKGROUND

Bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH) remains a devastating clinical complication seriously affecting the therapeutic outcome of preterm infants. Hence, early prevention and timely diagnosis prior to pathological change is the key to reducing morbidity and improving prognosis. Our primary objective is to utilize machine learning techniques to build predictive models that could accurately identify BPD infants at risk of developing PH.

METHODS

The data utilized in this study were collected from neonatology departments of four tertiary-level hospitals in China. To address the issue of imbalanced data, oversampling algorithms synthetic minority over-sampling technique (SMOTE) was applied to improve the model.

RESULTS

Seven hundred sixty one clinical records were collected in our study. Following data pre-processing and feature selection, 5 of the 46 features were used to build models, including duration of invasive respiratory support (day), the severity of BPD, ventilator-associated pneumonia, pulmonary hemorrhage, and early-onset PH. Four machine learning models were applied to predictive learning, and after comprehensive selection a model was ultimately selected. The model achieved 93.8% sensitivity, 85.0% accuracy, and 0.933 AUC. A score of the logistic regression formula greater than 0 was identified as a warning sign of BPD-PH.

CONCLUSIONS

We comprehensively compared different machine learning models and ultimately obtained a good prognosis model which was sufficient to support pediatric clinicians to make early diagnosis and formulate a better treatment plan for pediatric patients with BPD-PH.

Risk of dysphagia in a population of infants born pre-term: characteristic risk factors in a tertiary NICU

OBJECTIVE

To examine the prevalence and characteristics of dysphagia and suck-swallow-breath incoordination as phenotypes of oral feeding difficulties.

METHOD

A cross-sectional study with secondary data collected consecutively over 2 years from October 2020 to October 2022 to measure the prevalence of swallowing and oral feeding difficulty in preterm infants using Flexible endoscopic evaluation of swallowing examination at the tertiary Integrated Dysphagia Clinic.

RESULTS

The prevalence of swallowing disorders was 25 % and the prevalence of suck-swallow-breath incoordination was 62.5 %. The significant risk factor that may show a possible correlation with oral feeding difficulty was mature post-menstrual age (p = 0.006) and longer length of stay (p = 0.004). The dominant percentage of upper airway abnormality and disorder were retropalatal collapse (40 %), laryngomalacia (42.5 %), paradoxical vocal cord movement (12.5 %), and gastroesophageal reflux disease (60 %). The dominant characteristic of oral motor examination and flexible endoscopic evaluation of swallowing examination was inadequate non-nutritive sucking (45 %), inadequate postural tone (35 %), and inadequate nutritive sucking (65 %).

CONCLUSION

Dysphagia in preterm infants is mostly observed in those with mature post-menstrual age, longer length of stay, and the presence of gastroesophageal reflux disease with inadequate non-nutritive sucking and nutritive sucking abilities. Suck-swallow-breath incoordination is primarily observed in those with immature post-menstrual age, a higher prevalence of cardiopulmonary comorbidity, and a higher prevalence of upper airway pathologies (laryngomalacia, paradoxical vocal cord movement) with inadequate nutritive sucking ability.

Delivering Low Tidal Volume With Anesthesia and ICU Ventilators in a Neonatal Lung Model

BACKGROUND

Mechanical ventilation of the neonate requires ventilators than can deliver precise and accurate tidal volume (VT) and PEEP to avoid lung injury. Due to small neonatal VT and the disproportionate effect of endotracheal tube leak in these patients, accomplishing precise and accurate VT delivery is difficult. Whereas neonatal ICU ventilators are validated in this population, thorough studies testing the performance of anesthesia ventilators in delivering small VT in neonates are lacking.

METHODS

Three anesthesia ventilators, Dräger Apollo, GE Avance, and Getinge Flow-i; and 2 ICU ventilators, Medtronic PB980 and Nihon Kohden NKV-550, were tested under volume control mode at VT of 5, 20, 40, and 60 mL. Three combinations of lung compliance and airway resistance were tested using a Servo ASL 5000 lung simulator.

RESULTS

In a scenario without leak, the measured VT was greater than the set VT by > 10% in the Apollo (21.0% [18.8-26.0]); measured VT was less than the set VT by > 10% in the Flow-i (-19% [-20.8 to -18.7]). The Avance, PB980, and NKV-550 presented a volume error < 10% (-9.50% [-10.8 to -4.4], -5.8% [-11.8 to -3.5], and 5.4% [-4.5 to 18.9], respectively). Considering all combinations of set VT, leaks, and respiratory mechanics, none of the anesthesia ventilators were able to deliver a median measured VT within a 10% error. The bias between measured VT and set VT varied widely among ventilators (from 4.27 mL to -10.59 mL). Additionally, in the Apollo ventilator, PEEP was underdelivered with the largest leak value.

CONCLUSIONS

Our results suggest that in comparison with the 2 neonatal ICU ventilators tested, the anesthesia ventilators did not greatly differ in terms of VT delivery in the presence of a gas leak.

Duration of mechanical ventilation and clinical outcomes in very low birth weight infants: A single center 10-years cohort study

BACKGROUND

Despite the important role of MV in reducing mortality in very preterm infants, its use is often associated with complications. The study was aimed to determine the duration of mechanical ventilation (MV), which significantly increased the risk of adverse outcomes in very low birth weight (VLBW) infants.

METHODS

Data obtained from a prospectively created computer database were used in a retrospective cohort study. The database included information about 1980 VLBW infants <32 weeks of gestation who were cared for at the tertiary care center between January 2010 and December 2020.

RESULTS

Out of 1980 VLBW infants, 1086 (55%) were ventilated sometime during the hospital stay. 678 (62.43%) of ventilated babies survived until discharge. With ROC analysis, it was identified that MV duration of 60.5 hours had 79.3% sensitivity and 64.6% specificity for the prediction of BPD with the AUC of 0.784 (95% CI 0.733-0.827; p < 0.0001). The duration of MV above 60.5 hours was a significant risk factor for bronchopulmonary dysplasia (aOR 6.005, 95% CI 3.626-9.946), death (aOR 3.610, 95% CI 2.470-5.276), bronchopulmonary dysplasia/death (aOR 4.561, 95% CI 3.328-6.252), sepsis (aOR 1.634, 95% CI 1.168-2.286), necrotizing enterocolitis (aOR 2.606, 95% CI 1.364-4.980), and periventricular leukomalacia (aOR 2.191, 95% CI 1.241-3.867).

CONCLUSIONS

Duration of MV longer than 60.5 hours is an independent risk factor for adverse outcomes in VLBW infants. It is essential to increase and optimize efforts to avoid MV or extubate very preterm infants as soon as possible, before reaching the established threshold duration of invasive respiratory support.

Effects of critical illness on the functional status of children with a history of prematurity

OBJECTIVE

To evaluate the effects of critical illness on the functional status of children aged zero to 4 years with or without a history of prematurity after discharge from the pediatric intensive care unit.

METHODS

This was a secondary cross-sectional study nested in an observational cohort of survivors from a pediatric intensive care unit. Functional assessment was performed using the Functional Status Scale within 48 hours after discharge from the pediatric intensive care unit.

RESULTS

A total of 126 patients participated in the study, 75 of whom were premature, and 51 of whom were born at term. Comparing the baseline and functional status at pediatric intensive care unit discharge, both groups showed significant differences (p < 0.001). Preterm patients exhibited greater functional decline at discharge from the pediatric intensive care unit (61%). Among patients born at term, there was a significant correlation between the Pediatric Index of Mortality, duration of sedation, duration of mechanical ventilation and length of hospital stay with the functional outcomes (p = 0.05).

CONCLUSION

Most patients showed a functional decline at discharge from the pediatric intensive care unit. Although preterm patients had a greater functional decline at discharge, sedation and mechanical ventilation duration influenced functional status among patients born at term.

Less Invasive Surfactant Administration: A Review of Current Evidence of Clinical Outcomes With Beractant

Evidence supporting clinical recommendations or approval for less invasive surfactant administration (LISA) has primarily examined heterogeneous or small-volume (e.g., 1.25-2.5 mL/kg) animal-derived surfactant regimens. To address the evidence gap for larger-volume (e.g., 4-5 mL/kg) animal-derived surfactants, the aim of this review was to evaluate and summarize LISA literature for widely used larger-volume beractant. Surfactant treatment and the LISA technique were initially summarized. The available literature on beractant with LISA was thoroughly assessed and reviewed, including a recent systematic analysis, studies from regions where access or preferences may influence reliance on larger-volume surfactants, and investigations of short- and long-term outcomes. The available literature indicated improved short-term outcomes, including less need for mechanical ventilation, death, or bronchopulmonary dysplasia, and no negative long-term developmental outcomes when beractant was administered via LISA compared with older, more invasive techniques. The rates of short-term outcomes were similar to those previously observed in examinations of LISA with small-volume surfactants, including in populations reflecting very preterm infants. As uptake of LISA is expected to increase, future research directions for larger-volume surfactants include cost-effectiveness evaluations and robust examinations of repeat dosing and surfactant reflux to further inform clinical practice. This review provides a detailed assessment of the literature describing surfactant and LISA, with a focus on studies of beractant. Collectively, the available evidence supports the use of beractant with LISA based both on short-term and long-term outcomes relative to more invasive techniques and comparability of outcomes with small-volume surfactants and may be valuable in guiding clinical decision-making.

Longitudinal changes in lung function in very prematurely born young people receiving high-frequency oscillation or conventional ventilation from birth

OBJECTIVE

To examine changes in lung function over time in extremely prematurely born adolescents.

WORKING HYPOTHESIS

Changes in lung function during adolescence would vary by ventilation mode immediately after birth.

STUDY DESIGN

Longitudinal follow-up study.

PATIENT SUBJECT SELECTION

Participants from the United Kingdom Oscillation Study who were randomized at birth to high-frequency oscillation (HFO) or conventional ventilation (CV) were assessed at 11-14 years (n = 319) and at 16-19 years (n = 159).

METHODOLOGY

Forced expiratory flow (FEF), forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and lung volumes including functional residual capacity (FRC) were reported as z-scores. The diffusion capacity of the lungs for carbon monoxide (DLCO) was measured. Lung function trajectories were compared by mode of ventilation using mixed models. Changes in z-scores were scaled to 5-year average follow-up.

RESULTS

There were significant changes in the mean FEF75, FEF50, FEF25, FEV1, FVC, and DLCO z-scores within the CV and HFO cohorts, but no significant differences in the changes between the two groups. The mean FRC z-score increased in both groups, with an average change of greater than one z-score. The mean FEV1/FVC z-score increased significantly in the CV group, but not in the HFO group (difference in slopes: p = 0.02). Across the population, deterioration in lung function was associated with male sex, white ethnicity, lower gestational age at birth, postnatal corticosteroids, oxygen dependency at 36 weeks postmenstrual age, and lower birth weight, but not ventilation mode.

CONCLUSIONS

There was little evidence that the mode of ventilation affected changes in lung function over time.

Early extubation is associated with shorter duration of mechanical ventilation and lower incidence of bronchopulmonary dysplasia

INTRODUCTION

Respiratory care of extremely preterm infants remains a challenge. The majority require invasive mechanical ventilation (MV), which is a contributing factor in developing bronchopulmonary dysplasia (BPD). It is important to keep MV to a minimum but there have been concerns that attempting extubation too early increases the risk for atelectasis, re-intubation, and further lung trauma. The aim of this study was to compare two different approaches to extubation.

METHODS

Single-center, retrospective cohort study including infants born at 22 + 0-25 + 6 weeks during 2005-2009 and 2011-2015, before and after implementing guidelines recommending delayed extubation. Primary outcomes were BPD, duration of MV and length of hospital stay.

RESULTS

Eighty-eight infants in the early era and 102 infants in the late era were included. Infants in the first period were younger at first extubation attempt, and a higher number of infants were extubated within 24 h, 72 h, and one week after birth. The number of infants re-intubated and postnatal age at re-intubation did not differ between the groups. The incidence of severe BPD was 28% in the early period compared to 48% in the later (p < 0.01). Infants in the late period had longer duration of MV (17 vs 27 days, p < 0.01) but similar length of hospital stay (118 vs 123, p = 0.21).

CONCLUSION

After implementing guidelines recommending delayed extubation, the incidence of severe BPD was higher and the duration of MV was longer. This supports the strategy to attempt extubation early even in extremely preterm infants.

Factors associated with recurrent wheezing in the first year of life among premature newborns from Neonatal Intensive Care Units

Abstract Objectives: to determine the prevalence and factors associated with recurrent wheezing in the first year of life among premature newborns from Neonatal Intensive Care Units, in the city of Montes Claros, northern Minas Gerais. Methods: cross-sectional study, with data collection from medical records of a follow-up clinic, interviews with mothers and, eventually, search in hospital records. Bivariate analyzes were carried out between sociodemographic and clinical characteristics and recurrent wheezing. Variables associated up to the level of 20% were analyzed by binary logistic regression, and associations defined by the Odds Ratio and respective 95% confidence intervals. Only variables associated with a 5% significance level were maintained in the final model of logistic regression. Results: among 277 infants studied, about one fifth (21.3%) were extremely low birth weight preterm and more than half (60.7%) had birth weight below 1500 grams. The prevalence of recurrent wheezing was 14.4% (CI95% = 10.3-18.4). Mechanical ventilation (OR = 2.12; CI95% = 1.09-4.76; p = 0.030) and oxygen therapy time ≥ 15 days (OR = 2.49; CI95%= 1.12-5.00; p = 0.010) were the risk factors for the event. Conclusions: there is a high prevalence of recurrent wheezing in the evaluated group and the associated variables reiterate the risk of prolonged oxygen therapy and mechanical ventilation for premature newborns.

Aerosolized Surfactant for Preterm Infants with Respiratory Distress Syndrome

Currently, the administration of surfactant to preterm infants with respiratory distress syndrome (RDS) mainly relies on intratracheal instillation; however, there is increasing evidence of aerosolized surfactant being an effective non-invasive strategy. We present a historical narrative spanning sixty years of development of aerosolization systems. We also offer an overview of the pertinent mechanisms needed to create and manage the ideal aerosolization system, with a focus on delivery, distribution, deposition, and dispersion in the context of the human lung. More studies are needed to optimize treatment with aerosolized surfactants, including determination of ideal dosages, nebulizer types, non-invasive interfaces, and breath synchronization. However, the field is rapidly evolving, and widespread clinical use may be achieved in the near future.

Haemodynamics and cerebral oxygenation of neonatal piglets in the immediate ex utero period supported by mechanical ventilation or ex utero oxygenator

KEY POINTS

The margin of human viability has extended to the extremes of gestational age (<24 weeks) when the lungs are immature and ventilator-induced lung injury is common. Artificial placenta technology aims to extend gestation ex utero in order to allow the lungs additional time to develop prior to entering an air-breathing environment. We compared the haemodynamics and cerebral oxygenation of piglets in the immediate period post-oxygenator (OXY) transition against both paired in utero measures and uniquely against piglets transitioned onto mechanical ventilation (VENT). Post-transition, OXY piglets became hypotensive with reduced carotid blood flow in comparison with both paired in utero measures and VENT piglets. The addition of a pump to the oxygenator circuit may be required to ensure haemodynamic stability in the immediate post-transition period.

ABSTRACT

Gestational age at birth is a major predictor of wellbeing; the lower the gestational age, the greater the risk of mortality and morbidity. At the margins of human viability (<24 weeks gestation) immature lungs combined with the need for early ventilatory support means lung injury and respiratory morbidity is common. The abrupt haemodynamic changes consequent on birth may also contribute to preterm-associated brain injury, including intraventricular haemorrhage. Artificial placenta technology aims to support oxygenation, haemodynamic stability and ongoing fetal development ex utero until mature enough to safely transition to a true ex utero environment. We aimed to characterize the impact of birth transition onto either an oxygenator circuit or positive pressure ventilation on haemodynamic and cerebral oxygenation of the neonatal piglet. At 112 days gestation (term = 115 days), fetal pigs underwent instrumentation surgery and transitioned onto either an oxygenator (OXY, n = 5) or ventilatory support (VENT, n = 8). Blood pressure (BP), carotid blood flow and cerebral oxygenation in VENT piglets rose from in utero levels to be significantly higher than OXY piglets post-transition. OXY piglet BP, carotid blood flow and carotid oxygen delivery (DO₂ ) decreased from in utero levels post-transition; however, cerebral regional oxygen saturation (rSO₂ ) was maintained at fetal-like levels. OXY piglets became hypoxaemic and retained CO₂ . Whether OXY piglets are able to maintain cerebral rSO₂ under these conditions for a prolonged period is yet to be determined. Improvements to OXY piglet oxygenation may lie in maintaining piglet BP at in utero levels and enhancing oxygenator circuit flow.

Predicting outcomes of mechanically ventilated premature infants using respiratory severity score

BACKGROUND

Extremely low birth weight (ELBW) infants have significant morbidities and higher mortality. The major morbidities are bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH) and retinopathy of prematurity (ROP). Release of proinflammatory cytokines has been implicated in the development of systemic inflammation that contributes to BPD aND ROP. Also, cumulative oxygen exposure in the first 3 days of life and use of mechanical ventilation was associated with 3-fold increase in severe IVH. Therefore, early ventilation and oxygenation may contribute significantly to morbidities in ELBW infants. Respiratory severity score (RSS), a product of Mean airway pressure (MAP) and FiO2, is a steady-state noninvasive assessment tool useful in infants to monitor the severity of respiratory failure. We used RSS, in the first 3 days of life of ELBW infants, to predict neonatal morbidities and mortality.

STUDY DESIGN

In a single-center retrospective cohort study in an urban setting, convenience sampling of ELBW infants meeting the study criteria who were mechanically ventilated at birth for the first 3 days of life were included. Time-weighted average RSS was plotted on receiver-operating characteristic (ROC) curve in the first 3 days of life to predict outcomes. Sensitivity, specificity, positive predictive value, negative predictive value and likelihood ratios were calculated.

RESULTS

A total of 69 infants qualified for the study. RSS in the first 3 days significantly predicted the composite outcome of death, ROP, IVH or BPD with an area under the curve (AUC) of 0.82 (p < 0.001). Individually, RSS predicted death, severe ROP and IVH with an AUC of 0.86, 0.77 and 0.71 respectively; but did not predict severe BPD (AUC 0.61). RSS was more sensitive and specific than each of its component; FiO₂ and MAP. Weighted RSS in the first 3 days had high-negative predictive value of 98.1% for death between 7 days and 36 weeks, 94.6% for ROP and 91.7% for IVH.

CONCLUSIONS

This study is the first to show that RSS in the first 3 days of life is a good predictor of composite neonatal outcomes: severe IVH, BPD, ROP, or mortality. Early RSS had a high positive predictive value for the composite outcome of morbidities/mortality and a high specificity for mortality, ROP, and IVH individually.

Pulmonary pneumatoceles in neonates

Pulmonary pneumatoceles were relatively common in neonates in the pre-surfactant era. In the current era of surfactant, noninvasive and gentle invasive ventilation there is a paucity of data on clinical characteristics and outcomes of pneumatoceles in neonates. The lesion generally resolves spontaneously, but a few cases follow a complicated course with formation of extensive and expanding lesions. To better understand the pathophysiology, clinical significance, natural history, complications, treatment options and prognosis of pulmonary pneumatoceles in neonates, an extensive research was performed on the databases of medical literature. The information collected in this review is important for the clinicians in decision-making, especially in the most difficult cases.

Influence of time under mechanical ventilation on bronchopulmonary dysplasia severity in extremely preterm infants: a pilot study

Background

The relation between mechanical ventilation (MV) and bronchopulmonary dysplasia (BPD) - a common disease in extremely premature newborn (PTNB) - is well stabilished, but is unknown, however, how much time under MV influences the severity of the disease.

Aim

To define the duration under MV with greater chance to develop moderate to severe BPD in extremely PTNB and to compare clinical outcomes before and during hospitalization among patients with mild and moderate to severe BPD.

Methods

Fifty-three PTNB were separated into mild and moderate to severe BPD groups and their data were analyzed. Time under MV with a greater chance of developing moderate to severe BPD was estimated by the ROC curve. Perinatal and hospitalization outcomes were compared between groups. A logistic regression was performed to verify the influence of variables associated to moderate to severe BPD development, such as pulmonary hypertension (PH), gender, gestational age (GA) and weight at birth, as well the time under MV found with ROC curve. The result of ROC curve was validated using an independent sample (n = 16) by Chi-square test.

Results

Time under MV related to a greater chance of developing moderate to severe BPD was 36 days. Moderate to severe BPD group had more males (14 vs 5, p = 0,047), longer time under MV (43 vs 19 days, p < 0,001), more individuals with PH (12 vs 3, p = 0,016), worse retinopathy of prematurity (grade 3, 2 vs 11, p = 0,003), longer hospital length of stay (109 vs 81,5 days, p < 0,001), greater PMA (41 vs 38 weeks, p < 0,001) and weight (2620 vs 2031 g, p < 0,001) at discharge and the mild BPD group had more CPAP use prior to MV (12 vs 7, p = 0,043). Among all variables included in logistic regression, only PH and MV < 36 days were significant in the model, explaining 72% of variation in moderate to severe BPD development. In the validation sample, prevalence of preterm infants who needed MV for more than 36 days in the moderate to severe BPD group was 100% (n = 6) and 0% in mild BPD group (p = 0,0001).

Conclusion

Time under MV related to moderate to severe BPD development is 36 days, and worst outcomes are related to disease severity. PH and time under MV for more than 36 days are related to development of moderate to severe BPD.

Pretreatment with adalimumab reduces ventilator-induced lung injury in an experimental model

Objective

To determine whether adalimumab administration before mechanical ventilation reduces ventilator-induced lung injury (VILI).

Methods

Eighteen rats randomized into 3 groups underwent mechanical ventilation for 3 hours with a fraction of inspired oxygen = 0.40% including a low tidal volume group (n = 6), where tidal volume = 8mL/kg and positive end-expiratory pressure = 5cmH2O; a high tidal volume group (n = 6), where tidal volume = 35mL/kg and positive end-expiratory pressure = 0; and a pretreated + high tidal volume group (n = 6) where adalimumab (100ug/kg) was administered intraperitoneally 24 hours before mechanical ventilation + tidal volume = 35mL/kg and positive end-expiratory pressure = 0. ANOVA was used to compare histological damage (ATS 2010 Lung Injury Scoring System), pulmonary edema, lung compliance, arterial partial pressure of oxygen, and mean arterial pressure among the groups.

Results

After 3 hours of ventilation, the mean histological lung injury score was higher in the high tidal volume group than in the low tidal volume group (0.030 versus 0.0051, respectively, p = 0.003). The high tidal volume group showed diminished lung compliance at 3 hours (p = 0.04) and hypoxemia (p = 0,018 versus control). Pretreated HVt group had an improved histological score, mainly due to a significant reduction in leukocyte infiltration (p = 0.003).

Conclusion

Histological examination after 3 hours of injurious ventilation revealed ventilator-induced lung injury in the absence of measurable changes in lung mechanics or oxygenation; administering adalimumab before mechanical ventilation reduced lung edema and histological damage.

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.

Less invasive surfactant administration in preterm infants with respiratory distress syndrome-an updated meta-analysis

BACKGROUND

Less invasive surfactant administration (LISA) seems to have a good application prospect both in experimental models and patients with respiratory distress syndrome (RDS). Data regarding the effect of LISA procedure on RDS are conflicting.

METHODS

A search was conducted by two investigators involved in this research in PubMed, Embase, and Cochrane databases for studies in English and in Wanfang, VIP, and Cnki databases for Chinese studies (all last launched on December 18, 2018). Odds ratio and weighted mean difference were calculated using a random-effects or fixed-effects model, depending on the data type and heterogeneity of the included studies.

RESULTS

The comparison of effectiveness on RDS: (1) with respect to mechanical ventilation (<72 hours) and mechanical ventilation (all time periods). Data showed significant differences between LISA/control groups. (2) With respect to days of mechanical ventilation, data showed no significant differences between LISA/control groups. (3) With respect to bronchopulmonary dysplasia, the analysis showed that there was significant difference between LISA group and control group. (4) Regarding days of supplementary oxygen therapy and hospital stay, no significant differences were found. The comparison of possible complications of RDS: (1) data for mortality, pneumothorax and pulmonary hemorrhage showed no differences in the two groups. (2) Data for retinopathy of preterm comparison showed significant difference between the two groups. (3) Regarding intraventricular hemorrhage/periventricular leukomalacia, significant differences were found between the two groups.

CONCLUSION

Based on the above evidences, LISA is an effective and safe treatment for preterm infants with RDS.

Acid Sphingomyelinase Inhibition Attenuates Cell Death in Mechanically Ventilated Newborn Rat Lung

RATIONALE

Premature infants subjected to mechanical ventilation (MV) are prone to lung injury that may result in bronchopulmonary dysplasia. MV causes epithelial cell death and halts alveolar development. The exact mechanism of MV-induced epithelial cell death is unknown.

OBJECTIVES

To determine the contribution of autophagy to MV-induced epithelial cell death in newborn rat lungs.

METHODS

Newborn rat lungs and fetal rat lung epithelial (FRLE) cells were exposed to MV and cyclic stretch, respectively, and were then analyzed by immunoblotting and mass spectrometry for autophagy, apoptosis, and bioactive sphingolipids.

MEASUREMENTS AND MAIN RESULTS

Both MV and stretch first induce autophagy (ATG 5-12 [autophagy related 5-12] and LC3B-II [microtubule-associated proteins 1A/1B light chain 3B-II] formation) followed by extrinsic apoptosis (cleaved CASP8/3 [caspase-8/3] and PARP [poly(ADP-ribose) polymerase] formation). Stretch-induced apoptosis was attenuated by inhibiting autophagy. Coimmunoprecipitation revealed that stretch promoted an interaction between LC3B and the FAS (first apoptosis signal) cell death receptor in FRLE cells. Ceramide levels, in particular C16 ceramide, were rapidly elevated in response to ventilation and stretch, and C16 ceramide treatment of FRLE cells induced autophagy and apoptosis in a temporal pattern similar to that seen with MV and stretch. SMPD1 (sphingomyelin phosphodiesterase 1) was activated by ventilation and stretch, and its inhibition prevented ceramide production, LC3B-II formation, LC3B/first apoptosis signal interaction, caspase-3 activation, and, ultimately, FLRE cell death. SMPD1 inhibition also attenuated ventilation-induced autophagy and apoptosis in newborn rats.

CONCLUSIONS

Ventilation-induced ceramides promote autophagy-mediated cell death, and identifies SMPD1 as a potential therapeutic target for the treatment of ventilation-induced lung injury in newborns.

The effect of Sustained Lung Inflation on Outcomes of Acute Respiratory Distress Syndrome in Preterm Infants Born in Shahid Sadoughi Hospital during 2018

Background:Respiratory distress syndrome is the chief reason of death in infants. Sustained lung inflation (SLI) may improve respiratory outcomes and reduce the demand for mechanical ventilation (MV). Given that only few studies have been done in this field so far, the current study aimed to evaluate the effect of SLI on outcomes of acute respiratory distress syndrome in preterm infants. Materials and methods:This randomized trial was conducted on preterm infants with respiratory distress syndrome in Shahid Sadoughi Hospital, Yazd, Iran, during 2018. Data were extracted from medical records. Infants born at 25-30 weeks of gestation were randomized into two groups with an equal number of subjects (n=30) in each one. In group 1 (cases), patients received SLI (25 cm H2O for 15 seconds) and nasal continuous positive airway pressure (nCPAP) (5 cm H2O) after oropharynx and nasal suction. In group 2 (controls), patients received only nCPAP (5 cm H2O). Both nCPAP and SLI and were delivered through a T-piece ventilator and neonatal mask. Results:In the current study, no serious differences were seen between case and control groups in terms of either quantitative parameters, including MV duration, Apgar score in the first minute, duration of oxygen therapy, gestational age, birth weight, nCPAP duration, and duration of hospitalization in NICU (P>0.05), or qualitative variables, including sex, pneumothorax rate, rate of intraventricular hemorrhage, need for mechanical ventilation during the first 72 hours of life, surfactant need, and mortality rate (p>0.05), except in cases of complications (p=0.019). Conclusions:According to the results of the current study, neither nCPAP alone, nor SLI and nCPAP had any effect on the duration, or need, or type of mechanical ventilation, while the incidence of complications in the nCPAP alone group (control group) was higher than that of combined nCPAP + SLI group (case group). It is suggested that future studies should be conducted on a larger sample size.

Comparison of NIV-NAVA and NCPAP in facilitating extubation for very preterm infants

BACKGROUND

Various types of noninvasive respiratory modalities that lead to successful extubation in preterm infants have been explored. We aimed to compare noninvasive neurally adjusted ventilatory assist (NIV-NAVA) and nasal continuous positive airway pressure (NCPAP) for the postextubation stabilization of preterm infants.

METHODS

This retrospective study was divided into two distinct periods, between July 2012 and June 2013 and between July 2013 and June 2014, because NIV-NAVA was applied beginning in July 2013. Preterm infants of less than 30 weeks GA who had been intubated with mechanical ventilation for longer than 24 h and were weaned to NCPAP or NIV-NAVA after extubation were enrolled. Ventilatory variables and extubation failure were compared after weaning to NCPAP or NIV-NAVA. Extubation failure was defined when infants were reintubated within 72 h of extubation.

RESULTS

There were 14 infants who were weaned to NCPAP during Period I, and 2 infants and 16 infants were weaned to NCPAP and NIV-NAVA, respectively, during Period II. At the time of extubation, there were no differences in the respiratory severity score (NIV-NAVA 1.65 vs. NCPAP 1.95), oxygen saturation index (1.70 vs. 2.09) and steroid use before extubation. Several ventilation parameters at extubation, such as the mean airway pressure, positive end-expiratory pressure, peak inspiratory pressure, and FiO2, were similar between the two groups. SpO2 and pCO2 preceding extubation were comparable. Extubation failure within 72 h after extubation was observed in 6.3% of the NIV-NAVA group and 37.5% of the NCPAP group (P = 0.041).

CONCLUSIONS

The data in the present showed promising implications for using NIV-NAVA over NCPAP to facilitate extubation.

Long-term outcomes of preterm infants treated with less invasive surfactant technique (LISA)

OBJECTIVE

The aim of this study is to compare the clinical outcomes at 24 months postmenstrual age of two populations receiving beractant replacement therapy using less invasive surfactant administration (LISA) versus intubation, administration of surfactant, and early extubation (INSURE). Hospital admission requirements, psychomotor development, and respiratory and neurological outcomes were studied.

STUDY DESIGN

This was a single-center, retrospective, and descriptive study with a sample of 60 patients (30 for each group) on nasal continuous positive airway pressure during the first 3 days of life, requiring surfactant administration.

RESULTS

We found no significant differences between both groups on psychomotor development and respiratory and neurological outcomes.

CONCLUSION

Compared to INSURE technique, the administration of surfactant by LISA is feasible and safe and reduces invasive mechanical ventilation exposure with no differences in the follow-up neurodevelopmental and respiratory outcomes at 24 postmenstrual age.

Preterm birth: Born too soon for the developing airway epithelium?

Birth prior to term interrupts the normal development of the respiratory system and consequently results in poor respiratory outcomes that persist throughout childhood. The mechanisms underpinning these poor respiratory outcomes are not well understood, but intrinsic abnormalities within the airway epithelium may be a contributing factor. Current evidence suggests that the airway epithelium is both structurally and functionally abnormal after preterm birth, with reports of epithelial thickening and goblet cell hyperplasia in addition to increased inflammation and apoptosis in the neonatal intensive care unit. However, studies focusing on the airway epithelium are limited and many questions remain unanswered; including whether abnormalities are a direct result of interrupted development, a consequence of exposure to inflammatory stimuli in the perinatal period or a combination of the two. In addition, the difficulty of accessing airway tissue has resulted in the majority of evidence being collected in the pre-surfactant era which may not reflect contemporary preterm birth. This review examines the consequences of preterm birth on the airway epithelium and explores the clinical relevance of currently available models whilst highlighting the need to develop a clinically relevant in vitro model to help further our understanding of the airway epithelium in preterm birth.

Plasma proteomics reveals gestational age-specific responses to mechanical ventilation and identifies the mechanistic pathways that initiate preterm lung injury

The preterm lung is particularly vulnerable to ventilator-induced lung injury (VILI) as a result of mechanical ventilation. However the developmental and pathological cellular mechanisms influencing the changing patterns of VILI have not been comprehensively delineated, preventing the advancement of targeted lung protective therapies. This study aimed to use SWATH-MS to comprehensively map the plasma proteome alterations associated with the initiation of VILI following 60 minutes of standardized mechanical ventilation from birth in three distinctly different developmental lung states; the extremely preterm, preterm and term lung using the ventilated lamb model. Across these gestations, 34 proteins were differentially altered in matched plasma samples taken at birth and 60 minutes. Multivariate analysis of the plasma proteomes confirmed a gestation-specific response to mechanical ventilation with 79% of differentially-expressed proteins altered in a single gestation group only. Six cellular and molecular functions and two physiological functions were uniquely enriched in either the extremely preterm or preterm group. Correlation analysis supported gestation-specific protein-function associations within each group. In identifying the gestation-specific proteome and functional responses to ventilation we provide the founding evidence required for the potential development of individualized respiratory support approaches tailored to both the developmental and pathological state of the lung.

Assessment of the neuropsychomotor development in the first year of life of premature infants with and without bronchopulmonary dysplasia

Objective

To compare the neuropsychomotor development in the first year of life of premature infants with and without bronchopulmonary dysplasia.

Methods

A cross-sectional retrospective study was conducted between January 1, 2014, and December 30, 2015, with premature infants weighing < 1,500g at birth and diagnosed with bronchopulmonary dysplasia at the corrected ages of 6 and 9 months, assessed using the DENVER II Developmental Screening Test. Quantitative variables were described as the means, medians and standard deviations. Variables with normal distribution were tested using Student's t test; otherwise, the Mann-Whitney test was used, considering significance at p-value < 0.05. Qualitative variables were expressed as frequencies and percentages. Logistic regression was used with odds ratio analysis to evaluate the effects of other variables as risk factors for changes in neuropsychomotor development.

Results

Infants with bronchopulmonary dysplasia showed greater developmental delay compared with those without bronchopulmonary dysplasia (p-value = 0.001). The factors associated with a higher incidence of changes in neuropsychomotor development, in addition to bronchopulmonary dysplasia, were antenatal steroid, gender, birth weight, 5-minute Apgar score, Score for Neonatal Acute Physiology-Perinatal Extension, duration of oxygen therapy, duration of mechanical ventilation and length of hospital stay. Other variables may also have influenced the result, such as drug use by mothers of infants with bronchopulmonary dysplasia.

Conclusion

Bronchopulmonary dysplasia associated with other pre- and postnatal factors may be considered a risk factor for delayed neuropsychomotor development in the first year of life in premature infants born weighing less than 1,500g.

[Clinical effect of bubble nasal continuous positive airway pressure versus conventional nasal continuous positive airway pressure in respiratory support for preterm infants with neonatal respiratory distress syndrome]

OBJECTIVE

To study the clinical effect and safety of bubble nasal continuous positive airway pressure (BNCPAP) versus conventional nasal continuous positive airway pressure (nCPAP) in respiratory support for preterm infants with neonatal respiratory distress syndrome (NRDS).

METHODS

A retrospective analysis was performed for the clinical data of 130 preterm infants with NRDS. Among them, 69 underwent BNCPAP and 61 underwent nCPAP. The two groups were compared in terms of mortality rate, duration of respiratory support, use of pulmonary surfactant (PS), and treatment failure rate, and the incidence rates of bronchopulmonary dysplasia (BPD) and retinopathy of prematurity (ROP), as well as the changes in blood gas pH, partial pressure of oxygen, and partial pressure of carbon dioxide. The safety was evaluated for both groups.

RESULTS

There were no significant differences between the BNCPAP group and the nCPAP group in sex distribution, gestational age, birth weight, Apgar score at 1 and 5 minutes after birth, delivery mode, and the severity of NRDS (P>0.05). No infants in the BNCPAP group died, and one infant in the nCPAP group died; there was no significant difference in the mortality rate between the two groups (P>0.05). There were also no significant differences between the two groups in the duration of noninvasive ventilation, treatment failure rate, the incidence rates of BPD and ROP, and the percentage of infants with a need for use or reuse of PS (P>0.05). After 8-12 hours of ventilation, there were no significant differences between the two groups in the changes in blood gas pH and oxygenation index (P>0.05), while the BNCPAP group had a significantly greater reduction in partial pressure of carbon dioxide than the nCPAP group (P<0.05). There were no significant differences between the two groups in the incidence rates of pneumothorax, nasal septal injury, and nasal mucosal injury (P>0.05).

CONCLUSIONS

BNCPAP and nCPAP have similar clinical effect and safety in respiratory support for preterm infants with NRDS.

Predicting Extubation Outcomes-A Model Incorporating Heart Rate Characteristics Index

OBJECTIVE

To test the hypothesis that in neonates on mechanical ventilation, heart rate characteristics index (HRCi) can be combined with a clinical model for predicting extubation outcomes in neonates.

STUDY DESIGN

HRCi and clinical data for all intended intubation-extubation events (episodes) were retrospectively analyzed between June 2014 and January 2015. Each episode started 6 hours pre-extubation or at the time of primary intubation if ventilation duration was shorter than 6 hours (baseline). The episodes ended at 72 hours postextubation for successful extubations or at reintubation for failed extubations. Mean of 6 hourly epoch HRCi-scores (baseline) or fold-changes (postextubation) were analyzed. Results are expressed as medians (IQR) for continuous data and proportions for categorical data. Multivariable logistic regression mixed model was used for statistical analysis.

RESULTS

Sixty-six infants contributed to 96 episodes (18 failed extubations, 78 successful extubations) in the study. Failed extubations had significantly longer duration of ventilation (65.3 hours, 19.94-158.2 vs 38.4, 16.5-71.3) and more culture positive sepsis (33.3% vs 3.8%) than successful extubations. Baseline HRCi scores (1.68, 1.29-2.45 vs 0.95, 0.54-1.86) and postextubation epoch-1 fold changes (1.25, 0.94-1.55 vs 0.94, 0.82-1.11) were higher in failed extubations compared with successful extubations. Multivariable linear mixed-effects regression was used to create prediction models for success of extubation, using relevant variables.

CONCLUSIONS

The baseline and postextubation HRCi were significantly higher in neonates with extubation failure compared with those who succeeded. Models using HRCi and clinical variables to predict extubation success may add to the confidence of clinicians considering extubation.

Efficacy of minimally invasive surfactant therapy in moderate and late preterm infants: A multicentre randomized control trial

BACKGROUND

Minimally invasive surfactant therapy (MIST) is a new strategy to avoid mechanical ventilation (MV) in respiratory distress syndrome. The primary aim of this study was to test MIST as a means of avoiding MV exposure and pneumothorax occurrence in moderate and late preterm infants (32 to 36 weeks' gestational age).

METHODS

This was a randomized controlled trial including three Canadian centres. Patients were randomized to standard management or to the intervention if they required nasal continuous positive airway pressure of 6 cm H2O and 35% FiO2 in the first 24 hours of life. Patients from the intervention group received MIST immediately after inclusion. The primary outcome was either need for MV or development of a pneumothorax requiring a chest tube. To ensure that clinicians were not biased toward delaying intubation in the intervention group, clinical failure criteria were also used as a primary outcome. The primary outcome was analyzed using bivariate and multivariate logistic regressions.

RESULTS

Among 45 randomized patients, 24 were assigned to MIST and 21 to standard management. Eight infants (33%) from the intervention group met the primary outcome criteria versus 19 (90%) in the control group (absolute risk reduction 0.57, 95% confidence interval 0.54 to 0.60). One patient in each group reached the primary outcome because of pneumothorax occurrence. The other patients were exposed to MV. None of the patients reached the clinical failure criteria.

CONCLUSION

MIST for respiratory distress syndrome management in moderate and late preterm infants was associated with a significant reduction of MV exposure and pneumothorax occurrence.

Limiting ventilator-associated lung injury in a preterm porcine neonatal model

PURPOSE

Preterm infants are prone to respiratory distress syndrome (RDS), with severe cases requiring mechanical ventilation for support. However, there are no clear guidelines regarding the optimal ventilation strategy. We hypothesized that airway pressure release ventilation (APRV) would mitigate lung injury in a preterm porcine neonatal model.

METHODS

Preterm piglets were delivered on gestational day 98 (85% of 115day term), instrumented, and randomized to volume guarantee (VG; n=10) with low tidal volumes (5.5cm³kg^-1) and PEEP 4cmH₂O or APRV (n=10) with initial ventilator settings: P_High 18cmH₂O, P_Low 0cmH₂O, T_High 1.30s, T_Low 0.15s. Ventilator setting changes were made in response to clinical parameters in both groups. Animals were monitored continuously for 24hours.

RESULTS

The mortality rates between the two groups were not significantly different (p>0.05). The VG group had relatively increased oxygen requirements (F_iO₂ 50%±9%) compared with the APRV group (F_iO₂ 28%±5%; p>0.05) and a decrease in PaO₂/FiO₂ ratio (VG 162±33mmHg; APRV 251±45mmHg; p<0.05). The compliance of the VG group (0.51±0.07L·cmH₂O^-1) was significantly less than the APRV group (0.90±0.06L·cmH₂O^-1; p<0.05).

CONCLUSION

This study demonstrates that APRV improves oxygenation and compliance as compared with VG. This preliminary work suggests further study into the clinical uses of APRV in the neonate is warranted.

LEVEL OF EVIDENCE

Not Applicable (Basic Science Animal Study).

[Effect of early caffeine treatment on the need for respirator therapy in preterm infants with respiratory distress syndrome]

OBJECTIVE

To study the efficacy of early caffeine treatment in preterm infants with respiratory distress syndrome (RDS).

METHODS

A prospective controlled clinical trial was performed. A total of 59 preterm infants with RDS were enrolled and divided into a caffeine group (30 infants) and a control group (29 infants). Caffeine was administered in the caffeine group and control group at the same dosage at 12-24 hours after birth and before extubation respectively. The respirator parameters and the incidence rates of ventilator-associated pneumonia (VAP) and apnea were compared between the two groups.

RESULTS

Compared with the control group, the caffeine group had significantly lower peak inspiratory pressure, peak fraction of inspired oxygen, and incidence rate of VAP (p<0.05), as well as significantly shorter intubation time, NCPAP time, and total duration of oxygen supply (p<0.05). In addition, the caffeine group had a significantly longer time to first onset of apnea after extubation (p<0.05) and significantly fewer times of onset of apnea 1-2 days after extubation (p<0.01), as compared with the control group.

CONCLUSIONS

Early caffeine treatment can reduce the need for assisted ventilation in preterm infants with RDS, help with early extubation and ventilator weaning, reduce the oxygen time in the late stage, reduce the incidence of VAP, and prevent the development of apnea after extubation.

Artificial placenta: Recent advances and potential clinical applications

Lung immaturity remains a major cause of morbidity and mortality in extremely premature infants. Positive-pressure mechanical ventilation, the method of choice for respiratory support in premature infants, frequently promotes by itself lung injury and a negative impact in the circulatory function. Extracorporeal lung support has been proposed for more than 50 years as a potential alternative to mechanical ventilation in the treatment of severe respiratory failure of extremely premature infants. Recent advances in this field included the development of miniaturized centrifugal pumps and polymethylpentene oxygenators, as well as the successful use of pump-assisted veno-venous extracorporeal gas exchange systems in experimental artificial placenta models. This review, which includes studies published from 1958 to 2015, presents an update on the artificial placenta concept and its potential clinical applications. Special focus will be devoted to the milestones achieved so far and to the limitations that must be overcome before its clinical application. Notwithstanding, the artificial placenta stands as a promising alternative to mechanical ventilation in extremely premature infants. Pediatr Pulmonol. 2016;51:643-649. © 2016 Wiley Periodicals, Inc.

[Efficacy of different preparations of budesonide combined with pulmonary surfactant in the treatment of neonatal respiratory distress syndrome: a comparative analysis]

OBJECTIVE

To study the efficacy of different preparations of budesonide combined with pulmonary surfactant (PS) in improving blood gas levels and preventing bronchopulmonary dysplasia (BPD) in preterm infants with neonatal respiratory distress syndrome (NRDS).

METHODS

A total of 184 preterm infants who developed NRDS within 4 hours after birth were randomly administered with PS + continuous inhalation of budesonide aerosol (continuous aerosol group), PS+budesonide solution (solution group), PS + single inhalation of budesonide aerosol (single aerosol group), and PS alone, with 46 neonates in each group. The changes in arterial blood gas levels, rate of invasive mechanical ventilation after treatment, time of assisted ventilation, rate of repeated use of PS, and the incidence of BPD were compared between the four groups.

RESULTS

On the 2nd to 4th day after treatment, pH, PCO2, and oxygenation index (FiO2/PaO2) showed significant differences among the four groups, and the continuous aerosol group showed the most improvements of all indicators, followed by the solution group, single aerosol group, and PS alone group. The continuous aerosol group had a significantly shorter time of assisted ventilation than the other three groups (P<0.05). The solution group had a significantly shorter time of assisted ventilation than the single aerosol and PS alone groups (P<0.05). The rate of invasive mechanical ventilation after treatment, rate of repeated use of PS, and incidence of BPD showed significant differences among the four groups (P<0.05), and the continuous aerosol group had the lowest rates, followed by the solution group.

CONCLUSIONS

A combination of PS and continuous inhalation of budesonide aerosol has a better efficacy in the treatment of NRDS than a combination of PS and budesonide solution. The difference in reducing the incidence of BDP between the two administration methods awaits further investigation with a larger sample size.

Neonatal ventilatory support and respiratory diseases in children up to six years of age: the 2004 Pelotas (Brazil) Birth Cohort study

The study's objective was to evaluate the association between neonatal ventilatory support and the subsequent occurrence of respiratory diseases in children up to six years of age. This was a population-based birth cohort study. The main exposure was ventilatory support at birth, defined as the use of nasal continuous positive airway pressure (NCPAP) and/or mechanical ventilation (MV) for more than three hours from the time of hospitalization at birth until the first 28 days of life. Outcomes were: chest wheezing in the twelve months prior to the follow-up interview, medical diagnosis of asthma any time in the child´s life, and occurrence of pneumonia up to six years of age. Crude and adjusted analyses for potential confounding variables were performed using Poisson regression. 3,624 children were analyzed. NCPAP plus MV or MV alone was associated with higher frequency of medical diagnosis of asthma, even after adjusting for maternal and child characteristics (PR = 2.24; 95%CI: 1.27-3.99). The results highlight medium-term respiratory complications associated with neonatal ventilatory support.

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.

Understanding the Impact of Infection, Inflammation, and Their Persistence in the Pathogenesis of Bronchopulmonary Dysplasia

The concerted interaction of genetic and environmental factors acts on the preterm human immature lung with inflammation being the common denominator leading to the multifactorial origin of the most common chronic lung disease in infants – ­bronchopulmonary dysplasia (BPD). Adverse perinatal exposure to infection/inflammation with added insults like invasive mecha nical ventilation, exposure to hyperoxia, and sepsis causes persistent immune dysregulation. In this review article, we have attempted to analyze and consolidate current knowledge about the role played by persistent prenatal and postnatal inflammation in the pathogenesis of BPD. While some parameters of the early inflammatory response (neutrophils, cytokines, etc.) may not be detectable after days to weeks of exposure to noxious stimuli, they have already initiated the signaling pathways of the inflammatory process/immune cascade and have affected permanent defects structurally and functionally in the BPD lungs. Hence, translational research aimed at prevention/amelioration of BPD needs to focus on dampening the inflammatory response at an early stage to prevent the cascade of events leading to lung injury with impaired healing resulting in the pathologic pulmonary phenotype of alveolar simplification and dysregulated vascularization characteristic of BPD.

Unraveling the Links Between the Initiation of Ventilation and Brain Injury in Preterm Infants

The initiation of ventilation in the delivery room is one of the most important but least controlled interventions a preterm infant will face. Tidal volumes (V T) used in the neonatal intensive care unit are carefully measured and adjusted. However, the V Ts that an infant receives during resuscitation are usually unmonitored and highly variable. Inappropriate V Ts delivered to preterm infants during respiratory support substantially increase the risk of injury and inflammation to the lungs and brain. These may cause cerebral blood flow instability and initiate a cerebral inflammatory cascade. The two pathways increase the risk of brain injury and potential life-long adverse neurodevelopmental outcomes. The employment of new technologies, including respiratory function monitors, can improve and guide the optimal delivery of V Ts and reduce confounders, such as leak. Better respiratory support in the delivery room has the potential to improve both respiratory and neurological outcomes in this vulnerable population.