Cause Of Neonatal Respiratory Distress Research Articles

Profile and Outcome of Neonatal Respiratory Distress: A Single-center Study

Abstract Background: Respiratory distress (RD) is one of the common indications of hospitalisation in the neonatal intensive care unit. Due to recent advances in clinical diagnosis and treatment, there is a need for data on the current profile and outcome of neonatal RD (NRD). Aims: To determine the clinical presentation, causes, risk factors, severity, and outcome of NRD. Patients and Methods: All neonates who presented with signs of RD were enrolled. Neonatal data such as birth weight, mode of delivery, gestational age, saturation on room air, mode of oxygen therapy, and onset and severity of RD were noted in predesigned pro forma. The severity of RD in term and pre-term neonates was assessed by Downe’s score and Silverman–Anderson’s score, respectively. Relevant investigations and treatment were started as per standard protocol. Results: The most common cause of NRD was RD syndrome (29%). Chest indrawing was the most prevalent sign of RD (90.0%). There was no significant association of gestational age with the severity of RD (P = 0.140), but the birth weight was significantly associated with the severity of RD (P = 0.002). Severe RD was associated with extreme prematurity, meconium-stained amniotic fluid and birth weight of <1.5 kg. The mortality rate was 12%, with meconium aspiration syndrome and RD syndrome being the common causes. Conclusions: Whatever the cause, RD can proceed to respiratory failure and death if it is not promptly diagnosed and treated. Therefore, any clinician providing care for neonates must be able to quickly identify the symptoms and degree of RD, distinguish between different aetiologies, and begin treatment plans to avoid future complications or mortality.

A Case Report on Congenital Nasal Pyriform Aperture Stenosis

Introduction: Congenital nasal pyriform aperture stenosis is a rare cause of neonatal respiratory distress.
 Observation: A female neonate was born by cesarean section at 39 SA for hydramnios, triple scarred uterus and macrosomia. He was macrosomic and had no facial dysmorphia, he presented at H1 of life with respiratory distress and noisy mouth breathing. He cyanosed with each feeding attempt. On facial CT, the choanae were patent with a median central incisor and piriformis orifice stenosis. Nasal breathing gradually normalized. The hospitalization lasted 8 days with a good evolution.
 Discussion: Congenital piriformis stenosis is a rare cause of congenital nasal obstruction. The association with median incisor syndrome is not exceptional. Diagnosis must be made early for proper management. Cyanosis and false airway can be life threatening. Associated abnormalities should be investigated by CT and MRI. Treatment is variable and may be surgical if the stenosis is severe. The prognosis is good in the absence of severe malformations or associated mental retardation.
 Conclusion: In case of neonatal respiratory distress, the Congenital pyriformis stenosis must be among the causes, a rapid diagnostic assessment and management are necessary.

Lung Ultrasound in the Early Diagnosis and Management of the Mild Form of Meconium Aspiration Syndrome: A Case Report

MAS is a common cause of neonatal respiratory distress in term and post-term neonates. Meconium staining of the amniotic fluid occurs in about 10-13% of normal pregnancies, and about 4% of these infants develop respiratory distress. In the past, MAS was diagnosed mainly on the basis of history, clinical symptoms, and chest radiography. Several authors have addressed the ultrasonographic assessment of the most common respiratory patterns in neonates. In particular, MAS is characterised by a heterogeneous alveolointerstitial syndrome, subpleural abnormalities with multiple lung consolidations, characterised by a hepatisation aspect. We present six cases of infants with a clinical history of meconium-stained fluid who presented with respiratory distress at birth. Lung ultrasound allowed the diagnosis of MAS in all the studied cases, despite the mild clinical picture. All children had the same ultrasound pattern with diffuse and coalescing B-lines, pleural line anomalies, air bronchograms, and subpleural consolidations with irregular shapes. These patterns were distributed in different areas of the lungs. These signs are specific enough to distinguish between MAS and other causes of neonatal respiratory distress, allowing the clinician to optimise therapeutic management.

Protocol for a multicenter, double-blind, randomized, placebo-controlled phase III trial of the inhaled β2-adrenergic receptor agonist salbutamol for transient tachypnea of the newborn (the REFSAL trial).

Transient tachypnea of the newborn (TTN), which results from inadequate absorption of fetal lung fluid, is the most common cause of neonatal respiratory distress. Stimulation of β-adrenergic receptors enhances alveolar fluid absorption. Therefore, the β2-adrenergic receptor agonist salbutamol has been proposed as a treatment for TTN. This study aims to evaluate the efficacy and safety of salbutamol as supportive pharmacotherapy together with non-invasive nasal continuous positive airway pressure (NIV/nCPAP) for the prevention of persistent pulmonary hypertension of the newborn (PPHN) in infants with TTN. This multicenter, double-blind, phase III trial will include infants with a gestational age between 32 and 42 weeks who are affected by respiratory disorders and treated in eight neonatal intensive care units in Poland. A total of 608 infants within 24 h after birth will be enrolled and randomly assigned (1:1) to receive nebulized salbutamol with NIV or placebo (nebulized 0.9% NaCl) with NIV. The primary outcome is the percentage of infants with TTN who develop PPHN. The secondary outcomes are the severity of respiratory distress (assessed with the modified TTN Silverman score), frequency of need for intubation, duration of NIV and hospitalization, acid-base balance (blood pH, partial pressure of O2 and CO2, and base excess), and blood serum ionogram for Na+, K+, and Ca2+. The Respiratory Failure with Salbutamol (REFSAL) study will be the first clinical trial to evaluate the efficacy and safety of salbutamol in the prevention of persistent pulmonary hypertension in newborns with tachypnea, and will improve short term outcomes. If successful, the study will demonstrate the feasibility of early intervention with NIV/nCPAP together with nebulized salbutamol in the management of TTN. The study protocol was approved by the Bioethics Committee of the Medical University of Warsaw, Warsaw, Poland on November 16, 2020 (decision number KB/190/2020). All procedures will follow the principles of the Declaration of Helsinki. The results of the study will be submitted for knowledge translation in peer-reviewed journals and presented at national and international pediatric society conferences. It is registered at ClinicalTrials.gov NCT05527704, EudraCT 2020-003913-36; Protocol version 5.0 from 04/01/2022.

Prevalence and Outcome of Management of Respiratory Distress Syndrome: A Systematic Review

The main goal of this review is about Respiratory distress syndrome, which starts within hours of delivery, is really a major cause of neonatal respiratory distress; it remains a leading cause of morbidity and mortality in preterm infants. The following search databases were used PubMed, the Web of Science, Science Direct, EBSCO, and the Cochrane Library. Utilizing Rayyan QCRI, studies papers were screened by title and abstract before being subjected to a full-text evaluation. This review invest

Congenital Nasal Pyriform Aperture Stenosis: Same CT Dimensions, Varied Scenarios.

Congenital nasal pyriform aperture stenosis (CNPAS) is a rare cause of neonatal respiratory distress. We report a case series of four infants with similar radiological dimensions but while two needed surgery, two could be managed conservatively. The clinical presentation of the child and the response to conservative treatment, rather than the radiological dimensions were the main predictors for surgical intervention.

Tools for assessing lung fluid in neonates with respiratory distress

BackgroundTransient tachypnea of the newborn (TTN), as a common cause of neonatal respiratory distress, needs to be distinguished from respiratory distress syndrome (RDS). Various modalities such as lung ultrasonography, cytokine analysis, and electrical cardiometry for the evaluation of lung fluid can be helpful for the exact diagnosis, however, clinical diagnosis has been applied mainly. This study aimed to evaluate the usefulness of the various tools for the diagnosis of TTN and RDS in neonates.MethodsThis study evaluated 22 late-preterm and term infants admitted to the neonatal intensive care unit of Gangnam Severance Hospital because of respiratory distress. Total 9 neonates were diagnosed with TTN and 13 had RDS. In addition to chest radiography, the LUS score was calculated by a neonatologist using the portable ultrasound device. Cytokines in the bronchoalveolar lavage fluid supernatant were measured. Thoracic fluid content was measured using an electrical cardiometry device.ResultsWe enrolled 22 patients with median gestational age, 37.1 weeks, and birth weight 3100 g. There is no difference in patient characteristics between RDS and TTN group. Lung ultrasound score was significantly higher in RDS than TTN (11 vs 6, p = 0.001). Score 0 is shown in all infants with TTN. Score 1 is shown as significantly more in RDS than TTN. Between the TTN and RDS groups, there were significant differences in the changes of thoracic fluid content (2 vs − 1.5, p < 0.001), IL-1β levels (2.5 vs 11.3, p = 0.02), and TNF-α levels (20.1 vs 11.2, p = 0.04).ConclusionWe found lung ultrasound and electrical cardiometry to be reliable diagnostic tools for assessing infants with respiratory distress among late-preterm and term infants. Further studies with a large number of patients are needed to confirm their clinical usefulness.

Comparison of inhaled salbutamol and intravenous furosemide in the treatment of transient tachypnea of the newborn regarding their safety and efficacy

Background Postnatal respiratory complications among term infants are common. The most commonly reported cause of neonatal respiratory distress is transient tachypnea of the newborn (TTN), with an estimated incidence of 0.5–2.8% of all newborns.Aim To evaluate and compare the efficacy and safety of inhaled salbutamol and intravenous (i.v.) furosemide in the treatment of TTN and to monitor of their possible adverse effects in neonates.Patients and methods This was a randomized controlled clinical trial on 100 neonates who were admitted immediately or shortly after birth owing to persistence of tachypnea to neonatal intensive care unit of pediatric hospitals, Cairo University, over a 1-year period. Our study included 100 neonates (25 in the salbutamol group, 25 in the furosemide group, and 50 in the control group) with TTN born between 35 and 39 weeks of gestational age. They were randomized in a blinded manner to receive one nebulized dose of salbutamol 0.15 mg/kg in 0.9% saline solution or i.v. furosemide 1 mg/kg once in addition to oxygen and i.v. fluids or received oxygen and i.v. fluids alone.Results The efficacy of inhaled salbutamol and furosemide was assessed by determining the respiratory rate, heart rate, TTN clinical score, and the level of respiratory support before receiving medication and 30 min, 1, and 4 h after drug therapy. The duration and level of respiratory support and the period of hospitalization were shorter in the salbutamol group. There was a significant decrease in the respiratory rate and TTN score in the salbutamol group 4 h after nebulized salbutamol.Conclusion Comparing the three groups after respiratory support, TTN score was significantly improved in the salbutamol group. The total duration of oxygen treatment in hours and total neonatal intensive care unit stay in days were significantly shorter in the salbutamol group than in furosemide and control groups. Regarding the safety of salbutamol, our study did not show a significant difference in adverse effects. Inhaled salbutamol treatment was effective in TTN without adverse events. Further studies at larger or repeated doses of furosemide may be needed.

Congenital retro-costo-xiphoid diaphragmatic hernia

Congenital diaphragmatic hernia is a common cause of neonatal respiratory distress. The right or left diaphragmatic cupola hernia is most often involved. Rarely, a retro -costo-xiphoidian or Larrey or Morgagni hernia is diagnosed as part of respiratory distress. We present a case of congenital retro -costo-xiphoid diaphragmatic hernia in a midline situation, involving the sternal portion and extending to the diaphragmatic domes on each side. The discovery was made antenatal by obstetric ultrasound from 21 weeks. At birth, there was minor respiratory distress. The management consisted of a reduction and placement of a polypropylene plate in the natal post by abdominal approach.

A study of profile of meconium aspiration syndrome in relation with birth weight and gestational age of newborns and their immediate outcome

Background: Meconium aspiration syndrome (MAS) is one of the common causes of neonatal respiratory distress. Overall frequency of meconium stained amniotic fluid (MSAF) ranges between 5 to 25%.Methods: Observational study was conducted on 96 newborns over a period of one year in the department of pediatrics, Himalayan Institute of Medical Sciences, Dehradun, Uttarakhand. All newborns, inborns and outborns with MSAF admitted in NICU of our hospital were taken. Results: Out of 876 babies those had MSAF, 96 babies developed MAS with 10.95% incidence. Common maternal risk factors noted with MAS was maternal diabetes mellitus in 11 (15.71%) cases. Babies born via LSCS developed MAS in 51 (53.12%) and in babies delivered vaginally 45 (46.87%). MAS occurred mainly in term with mean gestational age of 38 weeks with SD of 1.85 weeks. The mean birth weight of newborns with MAS was 2794 g with 524 g SD. Most common complication was birth asphyxia in 36 (37.5%). Mortality occurred in 11 (11.4%). Mean gestational age and birth weight of mortality in MAS was 38 weeks with 2.5 weeks SD and 2800 g with 723 g SD respectively. Statistically significant association noted between mortality due to MAS and birth weight as p value&lt;0.05, but no significant association noted between mortality and gestational age.Conclusions: MAS is a common cause of respiratory distress in newborns born through MSAF. With judicious use of available modes of ventilation and adjunctive therapies, infants with even the most severe MAS can usually be supported through the disease, with an acceptable burden of short-and long-term morbidity.

Respiratory Distress in the Newborn with Primary Ciliary Dyskinesia.

Primary ciliary dyskinesia (PCD) is inherited in a predominantly autosomal recessive manner with over 45 currently identified causative genes. It is a clinically heterogeneous disorder that results in a chronic wet cough and drainage from the paranasal sinuses, chronic otitis media with hearing impairment as well as male infertility. Approximately 50% of patients have situs inversus totalis. Prior to the development of chronic oto-sino-pulmonary symptoms, neonatal respiratory distress occurs in more than 80% of patients as a result of impaired mucociliary clearance and mucus impaction causing atelectasis and lobar collapse. Diagnosis is often delayed due to overlapping symptoms with other causes of neonatal respiratory distress. A work up for PCD should be initiated in the newborn with compatible clinical features, especially those with respiratory distress, consistent radiographic findings or persistent oxygen requirement and/or organ laterality defects

A rare cause of respiratory distress in a newborn: Pneumomediastinum

Pneumomediastinum is an uncommon cause of neonatal respiratory distress and occurs in approximately 2.5 per 1000 live births. Although, the most common cause of pneumomediastinum is an underlying lung disease, it can be seen in newborns who undergo resuscitation during delivery without a predisposing factor. Initial diagnosis by chest X-ray can be difficult in some cases. The “spinnaker-sail sign” is an uncommon radiological appearance of pneumomediastinum. Careful conservative management can result with spontaneous resolution without long-term sequelae. In this case report, we present a neonate who developed pneumomediastinum.

Accuracy and Reliability of Lung Ultrasound to Diagnose Transient Tachypnoea of the Newborn: Evidence from a Meta-analysis and Systematic Review.

Transient tachypnoea of the newborn (TTN) is one of the most common causes of neonatal respiratory distress (RD) during the newborn period. Chest radiography (CXR) is commonly used to rule out the diagnosis, but TTN is often misdiagnosed as neonatal respiratory distress syndrome (NRDS) on the basis of CXR alone. Increasing evidence suggests that lung ultrasound (LUS) may be a reliable diagnostic tool for transient tachypnoea of the newborn. However, studies of the diagnostic efficiency of LUS are still lacking. This study was aimed to evaluate the accuracy and reliability of LUS for diagnosing TTN by conducting a systematic review and meta-analysis. We searched for articles in the Embase, PubMed, and Cochrane Library databases from inception until May 31, 2020. The selected studies were diagnostic accuracy studies that reported the utility of LUS in the diagnosis of TTN. Two researchers independently extracted data and assessed quality using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. Then, we created a bivariate model of mixed effects to calculate the sensitivity and specificity of LUS in diagnosing TTN. A summary receiver operator characteristic (SROC) curve was constructed to summarize the performance characteristics of LUS. Six studies involving 617 newborns were included in the review. LUS had a pooled sensitivity of 0.98 (confidence interval [CI]: 0.92-1.00) and a specificity of 0.99 (CI: 0.91-1.00). The area under the curve for LUS was 1.00 (0.98-1.0). Meta-regression revealed that LUS had a significant diagnostic accuracy for TTN. The performance of ultrasound for the detection of TTN was excellent. Considering the various advantages of LUS compared with chest radiographs in diagnosing TTN, this study supports the routine use of LUS for the detection of TTN. · Lung ultrasound is a highly accurate diagnostic tool, which may be a viable and superior alternative to CXR, in diagnosing TTN.. · Lung ultrasound can help differentiate TTN from other etiologies of respiratory distress in neonates.. · There are still some controversies on the ultrasound diagnostic criteria of TTN..

The effects of inhaled β-adrenergic agonists in transient tachypnea of the newborn

Objective The objective of this study was to evaluate the efficacy of inhaled salbutamol for the treatment of transient tachypnea of the newborn (TTN). Background The most commonly reported cause of neonatal respiratory distress is TTN, with estimated incidence of 0.5–2.8% of all newborn. Patient and methods This is a randomized controlled trial study considering patient with even registration number as cases. Inhaled salbutamol or normal saline solution was administered to 60 infants diagnosed as having TTN. The response was evaluated by determining respiratory rate, heart rate, TTN clinical score, and level of respiratory support, before and at 30 min and 1 and 4 h after drugs therapy. The standard dose of salbutamol was 0.15 mg/kg added to 2 ml normal saline. The second group received dose of 2 ml nebulized (0.9%) normal saline only. Results The studied neonates were between 36 and 39 weeks of gestation. There were 30 (50%) males and 30 (50%) females. Comparing the two groups after 4 h of inhaled therapy, highly significant lower respiratory rate, oxygen, TTN score, respiratory support, and duration of hospitalization were detected in salbutamol group rather than saline group. Regarding arterial blood gas findings after 4 h of inhaled therapy, pH and partial pressure of arterial oxygen were significantly higher in salbutamol group than saline group. No significant difference was detected between the two groups regarding heart rate and serum potassium. Conclusion A single dose of inhaled salbutamol resulted in better clinical aspect and better laboratory outcome measures in cases of TTN.

An etiological study of respiratory distress in neonates in a tertiary care medical college hospital

Introduction: Respiratory distress is the most common cause of NICU admissions in newborns. Early diagnosis of cause of respiratory distress is important in the management of neonatal distress for better outcome. The high incidence of maternal risk factors and newborn receiving poor antenatal care continues to test the abilities of the neonatologist. Inspite of re¬cent advance in clinching diagnosis and management there are very less clinical studies on the neonatal respiratory distress in our country. Therefore, there is a need to know the etiological factors of the babies with respiratory distress. Materials and methods: A descriptive study of 150 neonates admitted to NICU of Sri Siddhartha Medical College and Hospital with clinical features suggestive of respiratory distress. All the newborn babies who developed respiratory distress within 72 hours of life were included in the study and those who developed respiratory distress after 72 hours of life was excluded from the study. Results: The commonest cause of neonatal respiratory distress in the present study was Respiratory distress syndrome (34%), followed by Transient tachypnoea of the newborn (30%), and Meconium aspiration syndrome (22.66%). LSCS was most common mode of delivery. Conclusion: The most common causes of respiratory distress were RDS, TTNB, MAS, and birth asphyxia. Proper antenatal care and early diagnosis of the antenatal complication and avoiding preterm deliveries will aid in the better outcome of the newborns. Early detection and appropriate management are essential to ensure better outcome in all infants presenting with respiratory distress.

Association of asymptomatic structural cardiac defects in neonates with transient tachypnea at birth: A case-control study

Background: Transient tachypnea of the newborn (TTNB) has been documented as the most common cause of neonatal respiratory distress, accounting for more than 40 percent of cases. Materials and Methods: This study was a prospective study on 75 patients (neonates who were born with TTNB) who underwent two-dimensional (2D) echocardiography (Echo) after tachypnea subsided. The controls (neonates who did not manifest tachypnea) were matched for birth weight, period of gestation, mode of delivery, and sex. Appropriate Chi-square tests were done for categorical variables, while Student's t-test was done for continuous variables. Results: Incidence of asymptomatic structural cardiac lesions detected by 2D Echo was significantly higher in neonates in the study group (n = 38; 50.66%) as compared to the control group (n = 7; 9.33%). This difference was statistically significant P < 0.0000002 (odds ratio 9.4586; 95% confidence interval 3.84–23.27). The most common cardiac lesion in both groups was atrial septal defect. Conclusion: The incidence of asymptomatic structural cardiac defects was found to be approximately five times higher in neonates manifesting TTNB (50.66% vs. 9.33%). Based on the findings of this study, screening for structural cardiac lesions by 2D echo is recommended in all neonates who manifest with TTNB.

Neonatal Respiratory Distress in Misan: Causes, Risk Factors, and Outcomes

Background: Respiratory distress is considered one of the most frequent causes of admission in the neonatal unit. Additionally, it is the leading cause of neonatal morbidity and mortality. This study aimed to determine the incidence of neonatal respiratory distress and its causes, risk factors, and outcomes to have a baseline data about the magnitude of respiratory distress with a further step toward the development of the neonatal field.Methods: This cross-sectional study was conducted in the neonatal care unit of Misan Hospital for Child and Maternity in Misan, Iraq, during one year. All the neonates who developed respiratory distress were included in this study according to the World Health Organization criteria.Results: The total number of neonatal admission during the study period was 870 cases among whom 738 (84.8%) subjects developed respiratory distress. The fatality rate was 21%, and the majority of deaths were found in respiratory distress syndrome (RDS) (67.1%). The RDS, transient tachypnea, and birth asphyxia were the major causes of neonatal respiratory distress. Statistically, prematurity, type of delivery, and number of babies at the delivery time were significantly associated with respiratory distress development.Conclusion: The incidence rate of neonatal respiratory distress was apparently high in Misan forming the most common cause of neonatal admission associated with a high mortality rate. Efforts toward preventing the causes and risk factors for neonatal respiratory distress, as well as, improving the efficacy of neonatal care unit are the significant challenges to improve the neonatal care and outcome.

Thoracic ultrasound accuracy for the investigation of initial neonatal respiratory distress

Thoracic ultrasound (TUS) is increasingly studied in neonatal respiratory distress but chest x-ray (CXR) remains the first-line exam. We aimed to evaluate its diagnostic performance for the investigation of unselected causes of neonatal respiratory distress in daily practice. We conducted a descriptive, prospective, and single-center diagnostic accuracy study in a tertiary hospital, including term and preterm newborns who needed a CXR because of respiratory conditions occurring at birth or during the first 24h of life. TUS was compared to the reference diagnosis, which was the association between the CXR results, the clinical initial context, and the patient's outcome. Fifty-two newborns were included and 104 hemi-thorax ultrasounds were analyzed. Sensitivity, specificity, positive and negative predictive values (PPV, NPV), diagnosis accuracy, as well as the positive and negative likelihood ratio of TUSs were 100% for respiratory distress syndrome (RDS), transient tachypnea of newborn (TTN), pneumomediastinum, meconium aspiration syndrome, and absence of pulmonary disease. TUS also showed 100% sensitivity and NPV for pneumothorax, but specificity was 97% and PPV was 50%. Kappa concordance between TUS and either CXR alone or the radiological/clinical gold standard was 0.79 and 0.95, respectively. ConclusionTUS at the newborn's bedside is efficient for investigating the main neonatal respiratory diseases, especially for the confirmation of RDS or TTN and for the exclusion of differential diagnosis or complications.

Congenital nasal pyriform aperture stenosis: Analysis of twenty cases at a single institution

ObjectivesCongenital nasal pyriform aperture stenosis (CNPAS) is a rare cause of neonatal respiratory distress that is difficult to treat. The primary objective of this study was to identify factors that predict the need for initial and revision surgery for CNAPS. The secondary objective is to identify risk factors in maternal history associated with the development of CNPAS. MethodsInfants with CNPAS between 2010 and 2017 were identified by ICD- 9 and 10 codes. Demographics, maternal history, anatomic features on imaging and medical and/or surgical management were reviewed. Frequencies, means and standard deviations were calculated. A p-value <.05 was considered significant. ResultsTwenty infants were included. All underwent flexible nasal endoscopy with inability to pass the scope in either nostril in 65% of infants. Nineteen had a CT scan and 13 had a MRI with midline defects in 76.3% and 53.8%, respectively. Solitary central mega-incisor was present in 65%. Half underwent surgical intervention at a mean age of 74.8 days, with 90% requiring revision surgery. There was no difference in pyriform aperture distance in the surgical and non-surgical patient subgroups (5.4 mm and 5.2 mm, p = .6 respectively). No specific variables were predictive of need for initial or revision surgery. Maternal diabetes mellitus (MDM) was found in 55% of mothers of infants with CNPAS. ConclusionPyriform aperture distance was not a predictor of surgical intervention. MRI should be considered in all infants with CNPAS as the rate of intracranial complications is high. MDM may be a risk factor for CNPAS.

The role of miR-431-5p in regulating pulmonary surfactant expression in vitro

BackgroundPulmonary surfactant is the complex mixture of lipid and protein that covers the alveolar surface. Pulmonary surfactant deficiency is one of the main causes of neonatal respiratory distress. Recent studies showed that miRNA plays an important role in lung development, but research into miR-431 regulation of pulmonary surfactant are sparse. In this study, we explored the regulatory role of miR-431-5p in the expression of pulmonary surfactant and identified its potential target gene, Smad4.MethodsThe bioinformatics tool TargetScan was used to predict the targets of miR-431. The expression of miR-431-5p was achieved via transfection of miR-431-5p mimics, an miR-431-5p inhibitor and corresponding negative control. The level of miR-431-5p was determined using quantitative real-time PCR. The CCK8 assay was conducted to confirm cell growth 12 h after transfection with miR-431-5p mimics, inhibitor or NC. Smad4 and surfactant-associated proteins in A549 were analyzed using western blot and quantitative real-time PCR.ResultsSmad4 was validated as a target of miR-431 in A549 cells. Overexpression of miR-431 accelerated A549 proliferation and inhibited A549 apoptosis. The mRNA and protein levels for the surfactant proteins (SP-A, SP-B, SP-C and SP-D) were found to be differentially expressed in A549 cells over- or under-expressing miR-431-5p.ConclusionOur results show that miR-431-5p is critical for pulmonary surfactant expression and that its regulation is closely related to the TGF-β/Smad4 pathway. These results will help us to study the pathophysiological mechanism of lung developmental diseases.