Inhaled versus systemic corticosteroids for the treatment of chronic lung disease in ventilated very low birth weight preterm infants

Efficacy and safety of pulmonary application of corticosteroids in preterm infants with respiratory distress syndrome: a systematic review and meta-analysis

BACKGROUND

Systemic corticosteroids as the frontline treatment of respiratory distress syndrome (RDS) in preterm infants are associated with adverse effects on growth and neurodevelopmental outcome, but the pulmonary administration of steroids may help prevent the development of bronchopulmonary dysplasia (BPD) without these side effects.

OBJECTIVES

To evaluate the efficacy and safety of pulmonary application of corticosteroids in preterm infants with RDS.

METHODS

MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, the WHO's International Clinical Trials Registry and grey literature were searched with no restriction on date and language of publication from inception to May 2016. Using a random-effect model, we pooled data from randomised controlled trials (RCTs) comparing inhaled or endotracheal corticosteroids with the standard of care, placebo or no other intervention in preterm infants with RDS.

RESULTS

We identified 873 potential citations and included 12 unique RCTs. Pulmonary corticosteroid therapy was associated with a significant reduction in the composite outcome of BPD or death (relative risk (RR) 0.85, 95% CI 0.76 to 0.96). Pulmonary application of corticosteroids significantly reduced the incidence of patent ductus arteriosus (PDA) (RR 0.82, 95% CI 0.74 to 0.92) and pneumonia (RR 0.57, 95% CI 0.35 to 0.92). There was no evidence of a significant difference regarding the risk of neurodevelopmental impairment or other side effects.

CONCLUSIONS

Pulmonary administration of corticosteroids reduces the incidence of BPD or death, pneumonia, PDA without causing any major side effects in preterm infants with RDS.

Early administration of inhaled corticosteroids for preventing chronic lung disease in very low birth weight preterm neonates

BACKGROUND

Chronic lung disease (CLD) remains a common complication among preterm infants. There is increasing evidence that inflammation plays an important role in the pathogenesis of CLD. Due to their strong anti-inflammatory properties, corticosteroids are an attractive intervention strategy. However, there are growing concerns regarding short- and long-term effects of systemic corticosteroids. Theoretically, administration of inhaled corticosteroids may allow for beneficial effects on the pulmonary system with a lower risk of undesirable systemic side effects.

OBJECTIVES

To determine the impact of inhaled corticosteroids administered to preterm infants with birth weight up to 1500 grams (VLBW) beginning in the first two weeks after birth for the prevention of CLD as reflected by the requirement for supplemental oxygen at 36 weeks' postmenstrual age (PMA).

SEARCH METHODS

Randomised and quasi-randomised trials were identified by searching the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 12) in the Cochrane Library (searched 5 January 2016), MEDLINE (1966 to 5 January 2016), Embase (1980 to 5 January 2016), CINAHL (1982 to 5 January 2016), reference lists of published trials and abstracts published in Pediatric Research or electronically on the Pediatric Academic Societies web-site (1990 to May 2016).

SELECTION CRITERIA

We included in this review randomised controlled trials of inhaled corticosteroid therapy initiated within the first two weeks of life in VLBW preterm infants.

DATA COLLECTION AND ANALYSIS

We evaluated data regarding clinical outcomes, including: CLD at 28 days or 36 weeks' PMA; mortality; combined outcome of death or CLD at 28 days of age and at 36 weeks' PMA; the need for systemic corticosteroids; failure to extubate within 14 days; and adverse effects of corticosteroids. All data were analysed using Review Manager (RevMan) 5. Meta-analyses were performed using relative risk (RR) and risk difference (RD), along with their 95% confidence intervals (CI). If RD was significant, the number needed to treat for an additional beneficial outcome (NNTB) was calculated. We used the GRADE approach to assess the quality of evidence.

MAIN RESULTS

According to GRADE the quality of the studies was moderate. Three additional trials are included in this update. The present review includes data analyses based on 10 qualifying trials that enrolled 1644 neonates. There was no significant difference in the incidence of CLD at 36 weeks' PMA in the inhaled steroid versus the placebo group (5 trials, 429 neonates) among all randomised (typical RR 0.97, 95% CI 0.62 to 1.52; typical RD -0.00, 95% CI -0.07 to 0.06). There was no heterogeneity for this outcome (typical RR I² = 11%; typical RD I² = 0%). There was a significant reduction in the incidence of CLD at 36 weeks' PMA among survivors (6 trials, 1088 neonates) (typical RR 0.76, 95% CI 0.63 to 0.93; typical RD -0.07, 95% CI -0.13 to -0.02; NNTB 14, 95% CI 8 to 50). There was a significant reduction in the combined outcome of death or CLD at 36 weeks' PMA among all randomised neonates (6 trials, 1285 neonates) (typical RR 0.86, 95% CI 0.75 to 0.99; typical RD -0.06, 95% CI -0.11 to -0.00) (P = 0.04); NNTB 17, 95% CI 9 to infinity). There was no significant heterogeneity for any of these analyses (I² = 0%). A lower rate of reintubation was noted in the inhaled steroid group compared with the control group in one study. There were no statistically significant differences in short-term complications between groups and no differences in adverse events at long-term follow-up reported. Long-term follow-up of infants enrolled in the study by Bassler 2015 is ongoing.

AUTHORS' CONCLUSIONS

Based on this updated review, there is increasing evidence from the trials reviewed that early administration of inhaled steroids to VLBW neonates is effective in reducing the incidence of death or CLD at 36 weeks' PMA among either all randomised infants or among survivors. Even though there is statistical significance, the clinical relevance is of question as the upper CI limit for the outcome of death or CLD at 36 weeks' PMA is infinity. The long-term follow-up results of the Bassler 2015 study may affect the conclusions of this review. Further studies are needed to identify the risk/benefit ratio of different delivery techniques and dosing schedules for the administration of these medications. Studies need to address both the short- and long-term benefits and adverse effects of inhaled steroids with particular attention to neurodevelopmental outcome.

Optimal delivery of aerosols to infants during mechanical ventilation

PURPOSE

The objective of this study was to determine optimal aerosol delivery conditions for a full-term (3.6 kg) infant receiving invasive mechanical ventilation by evaluating the effects of aerosol particle size, a new wye connector, and timing of aerosol delivery.

METHODS

In vitro experiments used a vibrating mesh nebulizer and evaluated drug deposition fraction and emitted dose through ventilation circuits containing either a commercial (CM) or new streamlined (SL) wye connector and 3-mm endotracheal tube (ETT) for aerosols with mass median aerodynamic diameters of 880 nm, 1.78 μm, and 4.9 μm. The aerosol was released into the circuit either over the full inhalation cycle (T1 delivery) or over the first half of inhalation (T2 delivery). Validated computational fluid dynamics (CFD) simulations and whole-lung model predictions were used to assess lung deposition and exhaled dose during cyclic ventilation.

RESULTS

In vitro experiments at a steady-state tracheal flow rate of 5 L/min resulted in 80-90% transmission of the 880-nm and 1.78-μm aerosols from the ETT. Based on CFD simulations with cyclic ventilation, the SL wye design reduced depositional losses in the wye by a factor of approximately 2-4 and improved lung delivery efficiencies by a factor of approximately 2 compared with the CM device. Delivery of the aerosol over the first half of the inspiratory cycle (T2) reduced exhaled dose from the ventilation circuit by a factor of 4 compared with T1 delivery. Optimal lung deposition was achieved with the SL wye connector and T2 delivery, resulting in 45% and 60% lung deposition for optimal polydisperse (∼1.78 μm) and monodisperse (∼2.5 μm) particle sizes, respectively.

CONCLUSIONS

Optimization of selected factors and use of a new SL wye connector can substantially increase the lung delivery efficiency of medical aerosols to infants from current values of <1-10% to a range of 45-60%.

Respiratory morbidity at follow-up of small-for-gestational-age infants born very prematurely

BACKGROUND

The aim of this study was to determine whether small-for-gestational-age (SGA) infants born very prematurely had increased respiratory morbidity in the neonatal period and at follow-up.

METHODS

Data were examined from infants recruited into the United Kingdom Oscillation Study (UKOS). Of the 797 infants who were born at <29 wk of gestational age, 174 infants were SGA. Overall, 92% were exposed to antenatal corticosteroids and 97% received surfactant; follow-up data at 22-28 mo were available for 367 infants.

RESULTS

After adjustment for gestational age and sex, SGA infants had higher rates of supplementary oxygen dependency at 36 wk postmenstrual age (odds ratio (OR): 3.23; 95% confidence interval: 2.03, 5.13), pulmonary hemorrhage (OR: 3.07; 95% CI: 1.82, 5.18), death (OR: 3.32; 95% CI: 2.13, 5.17), and postnatal corticosteroid requirement (OR: 2.09; 95% CI: 1.35, 3.23). After adjustment for infant and respiratory morbidity risk factors, a lower mean birth weight z-score was associated with a higher prevalence of respiratory admissions (OR: 1.40; 95% CI: 1.03, 1.88 for 1 SD change in z-score), cough (OR: 1.28; 95% CI: 1.00, 1.65), and use of chest medicines (OR: 1.32; 95% CI: 1.01, 1.73).

CONCLUSION

SGA infants who were born very prematurely, despite routine use of antenatal corticosteroids and postnatal surfactant, had increased respiratory morbidity at follow-up, which was not due to poor neonatal outcome.

Differential effects of cholesterol and budesonide on biophysical properties of clinical surfactant

INTRODUCTION

Corticosteroids have been widely used in clinical medicine as a first-line therapy to modify the inflammatory response in many pulmonary and systemic diseases. Inhaled and intratracheally administered corticosteroids have a particular interest in that their use allows the clinician to circumvent systemic steroid side effects. However, it is vital that corticosteroids delivered via the lungs not interfere with surface activity of the pulmonary surfactant lining layer.

RESULTS

We found differential effects of cholesterol and budesonide on the biophysical properties of a cholesterol-free clinical surfactant preparation, Curosurf. At a low concentration up to 1%, both steroids play a similar role of fluidizing the surfactant film. However, when steroid concentration is increased to 10%, cholesterol induces a unique phase transition that abolishes the surface activity of the Curosurf film. By contrast, 10% budesonide simply fluidizes the film, thus having only limited effects on surface activity.

DISCUSSION

Together with those of a previous study using a cholesterol-containing surfactant, our findings suggest that cholesterol-free surfactant preparations may be more advantageous than cholesterol-containing preparations as a carrier of budesonide because a larger amount of the drug may be delivered to the lungs without significantly compromising the surface activity of pulmonary surfactant.

METHODS

Langmuir balance was used to study the effect of cholesterol and budesonide added at different concentrations on surface activity of Curosurf. Atomic force microscopy (AFM) was used to reveal their effects on the interfacial molecular organization and lateral structure of Curosurf films.

Postnatal corticosteroids for prevention and treatment of chronic lung disease in the preterm newborn

Despite significant progress in the treatment of preterm neonates, bronchopulmonary dysplasia (BPD) continues to be a major cause of neonatal morbidity. Affected infants suffered from long-term pulmonary and nonpulmonary sequel. The pulmonary sequels include reactive airway disease and asthma during childhood and adolescence. Nonpulmonary sequels include poor coordination and muscle tone, difficulty in walking, vision and hearing problems, delayed cognitive development, and poor academic achievement. As inflammation seems to be a primary mediator of injury in pathogenesis of BPD, role of steroids as antiinflammatory agent has been extensively studied and proven to be efficacious in management. However, evidence is insufficient to make a recommendation regarding other glucocorticoid doses and preparations. Numerous studies have been performed to investigate the effects of steroid. The purpose of this paper is to evaluate these studies in order to elucidate the beneficial and harmful effects of steroid on the prevention and treatment of BPD.