Features Of Respiratory Distress Syndrome Research Articles

Early Bubble Continuous Positive Airway Pressure Therapy for Premature Neonates with Respiratory Distress Syndrome

Objective: To determine the outcome of preterm neonates with the early introduction of bubble continuous positive airway pressure (CPAP). Methodology: This observational study was conducted in NICU of Shifa International Hospital, Islamabad from March 2017 to August 2017. Ninety preterm infants were enrolled with a gestational age of 28 to 37 weeks and with the clinical features of Respiratory Distress Syndrome (RDS). Infant variables that were recorded were birth weight, gestational age, and severity of RDS and Fio2 requirement. Bubble CPAP was started at 5cm of water and FiO2 adjusted to maintain SpO2 of 87 to 95%. The SPSS 26 version was used to analyze data. The Chi square test was used, with a P value of <0.05 considered significant. Results: The study included 90 neonates who were clinically diagnosed with RDS. To treat RDS, CPAP was started at the mean age of 5.27 hours of life with a standard deviation of 2.66 hours. 11 out of 90 (11.22%) babies had chest X-ray findings in favor of severe RDS; while X-rays of the remaining 79 (88.78%) showed mild to moderate RDS. Conclusion: CPAP is of valuable importance in low resource countries with a lack of ventilators and provides an adequate and conservative treatment method of mild to moderate RDS for preterm neonates. However, in cases of severe RDS, intubation and mechanical ventilation are often necessary.

A study on the comparison of minimally invasive surfactant therapy with insure technique of surfactant therapy in preterm babies with respiratory distress in a tertiary care hospital – A prospective cohort study

Background: Respiratory distress syndrome (RDS) is a common problem in preterm babies due to surfactant deficiency. Initially, babies were given surfactant therapy by intubation, surfactant administration, and extubation (INSURE) method. Minimally invasive surfactant therapy (MIST) is a novel method of surfactant administration without intubation to spontaneously breathing preterm babies with RDS without the removal of continuous positive airway pressure (CPAP). Aim: This study aims to compare the surfactant therapy in preterm babies with RDS through MIST and INSURE technique. Methods: This prospective, observational cohort study was conducted in the neonatology unit of Calcutta National Medical College and Hospital. A total of 212 preterm babies of <37 weeks of gestation with features of RDS, who require surfactant are taken and divided into two groups. Very sick babies with congenital anomalies are excluded from the study. In MIST group (n=102), 8 Fr feeding tube is used to deliver surfactant while the baby is on CPAP. In INSURE group (n=102), surfactant is given by intubation through endotracheal tube without CPAP and extubated. Results: Mean birth weight was 1.26 kg in MIST and 1.22 kg in INSURE. Mean gestational age was 31.33 weeks in MIST and 31.11 weeks in INSURE. It was observed that there is a significant difference in terms of duration of oxygen requirement, neonatal intensive care unit stay, and surfactant spillage during administration in MIST group compared to INSURE group. However, duration of mechanical ventilation, CPAP, number of doses of surfactant, sepsis, intraventricular hemorrhage, retinopathy of prematurity, pneumothorax, bronchopulmonary dysplasia, and mortality did not show significant difference in both the groups. Conclusion: MIST is safe, feasible, and more beneficial than INSURE technique.

Safety of Early Rescue Surfactant Replacement Therapy for Preterm Neonates with Respiratory Distress Syndrome at Neonatal Intensive Care Unit of a Tertiary Hospital

Introduction: Respiratory distress syndrome (RDS) is an acute disease of preterm neonates and is caused by the deficiency of pulmonary surfactant. Surfactant deficiency can lead to alveolar collapse, atelectasis, impaired gas exchange, severe hypoxia and acidosis. Surfactant replacement therapy (SRT) is an integral part of management of preterm neonates with respiratory distress syndrome. The objective of the study was to evaluate the safety of early rescue surfactant replacement therapy in RDS.
 Methods: This was a prospective observational study conducted in a 17 bedded teaching and referral NICU of Eastern Nepal over a period of seven months. All preterm neonates with clinical and radiological features of RDS were enrolled in the study. The safety of early rescue SRT was evaluated by measuring the outcomes: incidence of pulmonary haemorrhage, apnea, hypoxia and cardiac arrest. All data were entered into the worksheet of SPSS software version (19.0) and descriptive statistics including percentages and frequencies was analysed. The level of statistical significance adopted was p-value < 0.05. 
 Results: The survival rate of preterm babies with SRT was 64.7% (22 babies). The incidence / prevalence of pulmonary haemorrhage, apnea, hypoxia, and cardiac arrest during or immediately after SRT was 14.7%, 5.9%, 5.9% and 2.9% respectively. 
 Conclusions: This study suggests that SRT is an effective, safe and feasible intervention in level-3 neonatal units and has the potential to reduce neonatal mortality. The study also emphasises on the fact that SRT should be provided in settings where there is adequate manpower, professional skills and desired infrastructure to administer surfactant.

Continuous positive airway pressure delivery during less invasive surfactant administration: a physiologic study.

We sought to investigate the pressure delivery during less invasive surfactant administration, as we hypothesize that it might be reduced. Physiologic in vitro study in a ventilation lab, using different pressure generators, levels, and leaks in a model of neonatal airways/lung mimicking mechanical characteristics of respiratory distress syndrome. Pressure was measured at the lung and verified in vivo measuring pharyngeal pressure in 19 neonates under same conditions. Data were analyzed using repeated measures-analysis of variance. Pressure delivery in vitro is significantly and variably reduced during minimally invasive surfactant administration: pressure loss is ≈99% and ≈10-97%, during mouth opening and closure, respectively. Pressure loss seems independent from the type of CPAP and interface. In vivo measurements showed similar pressure drops. Pressure transmission during minimally invasive surfactant administration is significantly reduced or totally absent. Pressure drop occurs despite the increased airway resistances and the airflow limitation due to the tracheal catheterization, but is independent from the type of pressure generator and interface.

Clinical features of respiratory distress syndrome in neonates of different gestational ages

To study clinical features of respiratory distress syndrome (RDS) in neonates of different gestational ages (GA). According to GA, 133 neonates with RDS were classified into GA <34 weeks group (n=66), GA 34-36 weeks group (late preterm neonates; n=31), and GA ≥37 weeks group (full-term neonates; n=36). The mothers' medical history during pregnancy and the condition of the neonates at birth were retrospectively analyzed, and the clinical data were compared between groups. Prenatal corticosteroids supplementation in the GA <34 weeks group was more common than that in the GA 34-36 weeks group (P<0.05). Compared with the GA ≥37 weeks group and the GA 34-36 weeks group, the GA <34 weeks group showed a significantly lower rate of primary diseases, a significantly later time of the development of dyspnea (P<0.05), and a higher rate of intraventricular hemorrhage (P<0.05). Serum albumin levels in the GA <34 weeks group were significantly lower than in the GA ≥37 weeks group (P<0.05). The GA ≥37 weeks group and the GA 34-36 weeks group showed a significantly higher reuse rate of pulmonary surfactant (P<0.05). Use of high-frequency oscillatory ventilation was more common in the GA ≥37 weeks group compared with the GA <34 weeks group (P<0.05). The clinical features of RDS are different across neonates of different GA, suggesting that the pathogenesis of RDS may be different in neonates of different GA.

Heterogeneity of respiratory distress syndrome: risk factors and morbidity associated with early and late gestation disease.

BackgroundAlthough respiratory distress syndrome (RDS) is considered a disease of prematurity, there is evidence to suggest heterogeneity between early and late gestation RDS. We examined the epidemiologic features of RDS occurring at early and late gestation.MethodsWe conducted a retrospective cohort study including live births in the United States in 2005–06, with information obtained from the National Center for Health Statistics. Early (<32 weeks) and late gestation RDS (≥39 weeks) were contrasted in terms of risk factors and associations with pregnancy complications, obstetric intervention and co-morbidity. Logistic regression was used to quantify the effects of risk factors, while other associations were quantified descriptively.ResultsThere were 27,971 RDS cases, yielding an incidence of 6.4 per 1000 live births. Early and late gestation RDS differed in terms of risk factors, with factors such as multi-fetal gestation more strongly associated with early (adjusted odds ratio [aOR] 11.6, 95 % confidence interval 11.0–12.2) compared with late gestation RDS (aOR 3.66, 95 % confidence interval 2.68–4.98). The morbidity correlates of early and late gestation RDS also differed substantially; neonatal seizures were less strongly associated with early (OR 5.90, 95 % confidence interval 3.67–9.47) compared with late gestation RDS (OR 33.1, 95 % confidence interval 27.2–40.2), while meconium aspiration syndrome was not significantly associated with early gestation RDS (OR 1.87, 95 % confidence interval 0.94–3.72) and very strongly associated with late gestation RDS (OR 39.8, 95 % confidence interval 34.7–45.6).ConclusionsDifferences in risk factors and morbidity correlates of early and late gestation RDS suggest that these entities represent two distinct diseases.

A four-year retrospective review of very low birth weight babies seen at the University of Abuja Teaching Hospital, Abuja, Nigeria

To review the outcome of very low birthweight infants admitted into the Special Care Baby Unit (SCBU) of University of Abuja Teaching Hospital (UATH), Gwagwalada, Abuja, Nigeria. A retrospective review of medical records of very low birthweight (VLBW) babies seen at the SCBU of UATH over a 4-year period from April 2006 to March 2010, was undertaken. Data were obtained from patients' folders and analyzed. Overall survival was 60.8%. Survival of infants with birth weight below 1000 grams was 26.8% compared to 66.4% for those between 1000 and 1499 grams. The main determinants of survival were birth weight (p< 0.0001) and gestational age (p = 0.0106). Other predictors of outcome were development of features of respiratory distress syndrome within hours of delivery, recurrent apnoea, drainage of liquor of more than 18 hours before delivery, hyperkalaemia, lack of antenatal care and being born-before-arrival (outborn). Survival rate is low compared to values from other communities in developing countries but better than values from many centres in Nigeria. Timely and effective management of apnoea, respiratory distress syndrome and prevention of extremely low birthweight (ELBW) deliveries through adequate antenatal care are required to improve on the current survival rate.

Characteristics of Respiratory Distress Syndrome in Infants of Different Gestational Ages

The purpose of this study was to compare the risk factors, clinical characteristics, and complications of respiratory distress syndrome (RDS) in infants delivered very preterm, late preterm, and term in order to help optimize the management of RDS in neonates. A retrospective study was conducted on neonates admitted to the NICU between January 2006 and December 2010. The enrolled infants with RDS were categorized as very preterm (<32(0/7)weeks gestation), moderately preterm (32(0/7)-33(6/7) weeks), late preterm (34(0/7)-36(6/7) weeks), and term (37(0/7)-42(0/7) weeks). The rates, potential risk factors, clinical characteristics, and complications of RDS of these four groups were comparatively analyzed. There was an increasing trend in incidence of RDS among the NICU admissions annually. Caesarean section without labor was significantly associated with RDS in term and late preterm infants (P<0.001). Rates of requirements for ventilator and pulmonary surfactant were similar in very preterm and term infants but significantly lower in late preterm infants (P<0.001). The oxygenation index value was not substantially lower in late preterm and term infants compared to very preterm infants, and the arterial oxygenation efficiency was improved slowly (P<0.001). Incidence of pneumonia and occurrence of pneumothorax were significantly higher in term infants (P<0.001). Term infants with RDS showed an association of RDS with caesarean section without labor and lung infection. These infants also showed slower improvement of oxygenation after surfactant administration and mechanical ventilation, and they experienced a high rate of pneumothorax complication, which was also noticed in late preterm neonates.

The role of surfactant in respiratory distress syndrome.

The key feature of respiratory distress syndrome (RDS) is the insufficient production of surfactant in the lungs of preterm infants. As a result, researchers have looked into the possibility of surfactant replacement therapy as a means of preventing and treating RDS. We sought to identify the role of surfactant in the prevention and management of RDS, comparing the various types, doses, and modes of administration, and the recent development. A PubMed search was carried out up to March 2012 using phrases: surfactant, respiratory distress syndrome, protein-containing surfactant, protein-free surfactant, natural surfactant, animal-derived surfactant, synthetic surfactant, lucinactant, surfaxin, surfactant protein-B, surfactant protein-C.Natural, or animal-derived, surfactant is currently the surfactant of choice in comparison to protein-free synthetic surfactant. However, it is hoped that the development of protein-containing synthetic surfactant, such as lucinactant, will rival the efficacy of natural surfactants, but without the risks of their possible side effects. Administration techniques have also been developed with nasal continuous positive airway pressure (nCPAP) and selective surfactant administration now recommended; multiple surfactant doses have also reported better outcomes. An aerosolised form of surfactant is being trialled in the hope that surfactant can be administered in a non-invasive way. Overall, the advancement, concerning the structure of surfactant and its mode of administration, offers an encouraging future in the management of RDS.

Máscara laríngea ProSealTM como via de administração de surfactante no tratamento da síndrome do desconforto respiratório em recém-nascido pré-termo

The administration of surfactant via tracheal cannula with mechanical ventilation is the conventional treatment for infant respiratory distress syndrome. Hemodynamic and respiratory changes due to tracheal intubation and the need for premedication justify the search for less invasive alternatives of surfactant administration. The objective of this study was to describe the use of the ProSealTM laryngeal mask airway as an option for the treatment of respiratory distress syndrome in a premature infant born at 31 weeks of gestation, at 1335 g, with respiratory difficulty after the first hour of life and exhibiting the clinical and radiologic features of respiratory distress syndrome. The surfactant was administered with the use of the ProSealTM laryngeal mask airway at 3.5 hours of life. It was well tolerated, with no need for tracheal intubation. Normal gasometry and radiologic improvement were observed after three and six hours of administration. Oxygen administration was suspended after eight days, with no comorbidities at discharge. The laryngeal mask airway seems to be a painless and less invasive alternative to treat respiratory distress syndrome and may reduce the need for tracheal intubation and mechanical ventilation. The efficacy and advantages of this route of treatment should be confirmed in a study of an adequate sample.

Expression of Airway Epithelial Sodium Channel in the Preterm Infant Is Related to Respiratory Distress Syndrome but Unaffected by Repeat Antenatal β-Methasone

Background: The airway epithelial sodium channel (ENaC) is rate limiting for postnatal alveolar fluid clearance. Increased lung water content is a feature of respiratory distress syndrome (RDS), which is reduced by antenatal corticosteroid treatment in preterm infants. Objectives: Since corticosteroids also induce ENaC gene expression, we studied whether a repeat dose of antenatal β-methasone affects postnatal expression of airway ENaC. Methods: 17 pregnant women with imminent preterm birth were randomized to receive a single repeat dose of β-methasone (12 mg) or placebo (repeat β-methasone: 8 infants, gestational age (GA) 30.8 ± 2.2 weeks; placebo: 14 infants, GA 30.4 ± 2.7 weeks). Expression of α-, β- and γENaC subunits in nasal epithelium 1–5 and 20–29 h postnatally was analyzed with reverse transcription-PCR. Results: There were no differences between the study groups in RDS incidence or ENaC subunit expression (all p > 0.38). Regression coefficients for association of αENaC expression at 1–5 h with GA in infants with and without RDS differed significantly (p = 0.023). At 20–29 h, αENaC expression was lower in infants with RDS (p = 0.048). Conclusions: A single repeat dose of antenatal β-methasone did not increase ENaC expression, which may in part explain the absence of reduction in RDS incidence.

High Concentrations of Plasminogen Activator Inhibitor-1 in Lungs of Preterm Infants With Respiratory Distress Syndrome

Among preterm infants, respiratory distress syndrome (RDS) is characterized by the presence of intraalveolar fibrin deposition. Fibrin monomers inhibit surfactant function effectively. However, little is known about potential disturbances of intraalveolar fibrinolysis in RDS. We studied levels of major plasminogen activator inhibitor-1 (PAI-1), tissue-type plasminogen activator (tPA), and urokinase-type plasminogen activator (uPA) in lungs of preterm infants with RDS. The antigen levels of PAI-1, tPA, and uPA were measured in 262 samples of tracheal aspirate fluid collected from 37 intubated preterm infants during the first 2 postnatal weeks. To examine the expression of PAI-1, tPA, and uPA in lung tissue, immunohistochemical analyses were performed on autopsy specimens from 7 preterm infants with RDS and 6 newborn infants without pulmonary pathologic conditions. For infants with an immature surfactant profile, as indicated by lecithin/sphingomyelin ratios in tracheal aspirate fluid of < 10, PAI-1 levels and ratios of PAI-1 to uPA and tPA were significantly higher during postnatal days 1 to 2, compared with infants with lecithin/sphingomyelin ratios of > or = 10. Moreover, infants who subsequently developed bronchopulmonary dysplasia (BPD) (n = 15) had higher PAI-1 levels on days 3 to 4 and days 7 to 8 than did those who survived without BPD. For preterm infants with RDS, immunohistochemical analyses demonstrated increased expression of PAI-1, tPA, and uPA predominantly in alveolar epithelium. High concentrations of PAI-1 and an increased ratio of PAI-1 to uPA, with a concurrently less-increased ratio of PAI-1 to tPA, are associated with the severity of RDS among preterm infants during the first postnatal days. Pulmonary inhibition of fibrinolysis is a pathophysiologic feature of RDS and may play a role in the development of BPD.

Foxa2 is required for transition to air breathing at birth.

Toward the end of gestation in mammals, the fetal lung undergoes a process of differentiation that is required for transition to air breathing at birth. Respiratory epithelial cells synthesize the surfactant proteins and lipids that together form the pulmonary surfactant complex necessary for lung function. Failure of this process causes respiratory distress syndrome, a leading cause of perinatal death and morbidity in newborn infants. Here we demonstrate that expression of the forkhead gene Foxa2 in respiratory epithelial cells of the peripheral lung controls pulmonary maturation at birth. Newborn mice lacking Foxa2 expression in the lung develop severe pulmonary disease on the first day of life, with all of the morphological, molecular, and biochemical features of respiratory distress syndrome in preterm infants, including atelectasis, hyaline membranes, and the lack of pulmonary surfactant lipids and proteins. RNA microarray analysis at embryonic day 18.5 demonstrated that Foxa2-regulated expression of a group of genes mediating surfactant protein and lipid synthesis, host defense, and antioxidant production. Foxa2 regulates a complex pulmonary program of epithelial cell maturation required for transition to air breathing at birth.

Pulmonary clearance of 99mTc-DTPA in experimental surfactant dysfunction treated with surfactant instillation.

Breakdown of the alveolo-capillary barrier is a characteristic feature of respiratory distress syndrome. Restoration of alveolo-capillary barrier function may be an important aspect of surfactant replacement therapy. We examined the effect of surfactant instillation on alveolo-capillary barrier function in an experimental model of surfactant dysfunction by measuring pulmonary clearance of 99mTc-DTPA. Nineteen rabbits were tracheotomized and mechanically ventilated. Surfactant dysfunction was induced by administration of a synthetic detergent in aerosol form. Detergent was given to 13 rabbits; seven rabbits were then treated with instillation of natural surfactant, whereas six rabbits received saline. Six rabbits were used as untreated controls. An aerosol of 99mTc-DTPA was administered to all animals and the pulmonary clearance was measured with a gamma camera. 99mTc-DTPA cleared from the lungs with a half-life of 71 +/- 22 min in the control animals, 21.4 +/- 7.4 min in the surfactant-treated animals and 5.8 +/- 1.5 min in the saline-treated animals. The difference in half-life between groups was highly significant (P < 0.001). There was no change in arterial oxygenation or compliance in controls or in animals treated with saline. In animals treated with surfactant, a small transient reduction in arterial oxygen tension and a more long-standing reduction in compliance were observed. Surfactant treatment thus significantly attenuated the effect of detergent treatment but did not restore alveolo-capillary transfer of 99mTc-DTPA to normal.

Chest radiographic course after exogenous surfactant therapy in baboons with respiratory distress syndrome

Exogenous surfactant materials have been used under a variety of treatment protocols in cases of neonatal respiratory distress syndrome (RDS). To evaluate the differences in radiologic changes that follow either an early or late therapy with exogenous bovine surfactant, we reviewed 189 serially obtained chest radiographs from 48 premature baboons with RDS studied under different treatment regimen. Twenty-six animals were controls (100 chest films), and 22 received 100 mg/kg bovine surfactant instilled via the trachea in three study protocols (89 chest films). Surfactant was given within 10 min of birth in one group and at 2 h of age in the other. In 25/26 controls, radiologic evidence of severe RDS was seen by 2 h of age; these changes persisted in 15 animals at 24 h. By contrast, a rapid clearing of radiologic features of RDS was seen following surfactant instillation in all 22 (100%) animals within 4 h, but one (4.5%) of these 22 deteriorated at 9 h of age. Pulmonary interstitial emphysema (PIE) was seen in 9/26 (34.6%) and pneumothorax in 5/26 (19.2%) control animals, while 1/22 (4.5%) surfactant-treated animals developed PIE, and none had pneumothorax. The presence of a shunt via the patent ductus arteriosus did not affect radiographic findings in 20 animals studied by contrast injection. Therapy for patent ductus arteriosus (PDA) also had no substantial influence on the radiographic findings, or with regard to the pulmonary course. Radiographic clearing of RDS occurred approximately 18 to 20 h prior to the improvement in pulmonary compliance.(ABSTRACT TRUNCATED AT 250 WORDS)