Preterm birth, defined as birth occurring at less than 37 completed weeks of gestation, is a significant global health concern associated with numerous complications, including Respiratory Distress Syndrome (RDS). RDS, formerly known as hyaline membrane disease (HMD), is a disease typical of preterm infants caused by insufficient pulmonary surfactant in the alveoli. This surfactant deficiency leads to increased alveolar surface tension, causing atelectasis, reduced lung compliance, and impaired gas exchange, ultimately resulting in hypoxemia and hypercapnia. The incidence and severity of RDS are inversely related to gestational age and birth weight, with 60-80% of infants born at less than 28 weeks of gestation and 15-30% of infants born between 32 and 36 weeks of gestation being affected.

The management of RDS aims to establish and maintain adequate functional residual capacity (FRC) and oxygenation. A key principle in the treatment of RDS is to maintain patent alveoli at low lung volumes by supporting alveolar patency at the end of expiration despite surfactant deficiency. Continuous Positive Airway Pressure (CPAP) is a non-invasive ventilatory support that delivers a constant level of positive pressure to the airways throughout the respiratory cycle. This positive pressure helps to prevent alveolar collapse, improves lung compliance, reduces the work of breathing, and enhances oxygenation.

CPAP can be delivered through various systems, including bubble CPAP (BCPAP), nasal CPAP (NCPAP), and ventilator-based CPAP. In resource-limited settings, indigenously assembled CPAP (i-CPAP) systems have emerged as a cost-effective alternative to commercially manufactured systems. These systems, often based on the principle of bubble CPAP, can be assembled locally using readily available materials, significantly reducing the cost of providing this essential respiratory support. The widespread use of such systems has the potential for saving lives in smaller hospitals where mechanical ventilation may not be readily available.

Given the potential benefits of i-CPAP in managing RDS in preterm neonates in resource-constrained environments, this study was conducted to evaluate the clinical profile and outcomes of preterm babies with RDS admitted to the NICU of a tertiary care hospital who were treated with i-CPAP. The primary aim was to understand the effectiveness and safety of i-CPAP in this specific population.

 Review of Literature

The effectiveness of CPAP in managing RDS in preterm infants has been well-documented in numerous studies. Jain et al. (2016) conducted a study in India on indigenous bubble CPAP in managing RDS in newborns and reported a survival rate of 66.7% in the CPAP-managed group, highlighting its potential in resource-limited settings. Their study also suggested that indigenous bubble CPAP is an effective, non-invasive ventilation method in resource-limited settings, reducing mortality and morbidity in newborns with RDS.

Suresh Narayan et al. (2016) also investigated the efficacy of indigenous bubble CPAP in treating respiratory distress of newborns and found that a significant proportion of babies requiring CPAP were managed successfully. Their study indicated that the outcome was better in babies with increasing gestational age.

Rekha et al. (2018) compared bubble CPAP (B-CPAP) with indigenous CPAP (I-CPAP) in preterm newborns with RDS and found comparable survival rates and a significantly lower rate of severe nasal septal damage in the I-CPAP group. This suggests that i-CPAP can be as effective as other CPAP modalities with potentially fewer complications.

Talwar et al. (2019) conducted a study on indigenous bubble CPAP, revealing its effectiveness in improving outcomes in neonates with respiratory distress, with favourable outcomes in 73% of cases. Their cohort predominantly consisted of male neonates with a significant portion having a birth weight of less than 2.5 kg.

Waifu et al. (2020) emphasized the significant role of bubble nasal CPAP (bNCPAP) in reducing neonatal mortality, particularly in resource-constrained settings, highlighting its physiological benefits, indications, contraindications, and potential complications. The review supported the use of low-cost bNCPAP as a vital intervention in the global fight against neonatal mortality due to respiratory distress syndrome.

These studies collectively underscore the importance and potential of CPAP, including indigenously assembled systems, in the management of RDS in preterm infants, particularly in settings with limited resources. The present study contributes to this body of literature by specifically examining the clinical profile and outcomes associated with i-CPAP use in a tertiary care hospital NICU.

This was a prospective study conducted in the Paediatric NICU of a Government General Hospital in Guntur, Andhra Pradesh, India, from January 2023 to July 2024.

Study Population

The study population comprised 100 preterm babies of less than 37 weeks of gestation who were admitted to the NICU with a diagnosis of RDS.

Inclusion Criteria:

• Preterm babies with gestational age < 37 weeks.
• Presence of respiratory distress with a Silverman Anderson score of ≥3 within 6 hours of birth. The Silverman Anderson score assesses five clinical signs of respiratory distress: upper chest movement, lower chest movement, xiphoid retraction, nasal flaring, and expiratory grunt, with each sign scored from 0 to 2, resulting in a total score ranging from 0 (no distress) to 10 (severe distress).
• Chest X-ray suggestive of RDS. Radiographic findings typically include low lung volumes and microatelectasis, giving a ground-glass appearance with air bronchograms.

Exclusion Criteria:

• Babies with gestational age > 37 weeks.
• Newborns with respiratory distress due to other causes, such as birth asphyxia, meconium aspiration syndrome, sepsis, major congenital malformations, or inborn errors of metabolism.

Data Collection

Following informed written consent obtained from the parents of the enrolled babies prior to the commencement of the study, data was collected using a pre-structured proforma. The proforma included details on maternal antenatal history (including antenatal corticosteroid (ANC) administration), perinatal information (gestational age, mode of delivery, birth weight, Apgar scores), and the neonate's clinical condition at admission (Silverman Anderson score, initial investigations including complete blood picture (CBP), C-reactive protein (CRP), and chest X-ray).

During the period of i-CPAP therapy, the following parameters were monitored and recorded: duration of CPAP, pressure settings, inspired oxygen (FiO2), complications encountered (e.g., nasal injury, air leak), and outcomes (weaning to room air, need for escalation to mechanical ventilation, or death). Respiratory distress severity was graded by the Silverman Anderson score and monitored for clinical improvement.

Indigenous CPAP System

The i-CPAP system used in this study was assembled using locally available and cost-effective components. While the specific details of the assembly are not provided in the excerpts, indigenous CPAP systems often utilize a humidified oxygen source, tubing, a pressure-generating mechanism (often a water column, forming a bubble CPAP), and nasal prongs or a mask for interface with the neonate. The pressure delivered is typically adjusted by the depth of the expiratory limb of the circuit immersed in water.

Ethical Considerations

The study was conducted in accordance with the ethical principles outlined in the Declaration of Helsinki. Approval was obtained from the Institutional Ethics Committee of Guntur Medical College & Govt. General Hospital, Guntur. Confidentiality of patient information was strictly maintained throughout the study. Parents were informed about the purpose and procedures of the study, and their right to withdraw at any time without affecting the care provided to their baby was explained.

Statistical Analysis

Data entry was done using Microsoft Excel 2013, and statistical analysis was performed using SPSS V 16 software. Qualitative data were expressed as frequencies and percentages, while quantitative data were expressed as mean and standard deviation. Non-parametric tests, including the Chi-square test, were used for qualitative data, and unpaired t-tests were used for parametric data. Bar diagrams and pie charts were used for graphical representation of the data. A p-value of <0.05 was considered statistically significant

Distribution of the Study Population Based on Baseline Characteristics

Gestational Age: The distribution of the study population based on gestational age at birth is shown in Table 1. The majority of the neonates (53%) were born between 28 and 32 weeks of gestation, followed by 42% between 32 and 36 weeks, and 5% at less than 28 weeks.

Gender: The gender distribution revealed a slight male predominance, with 53% males and 47% females in the study population (Table 2).

Mode of Delivery: Normal vaginal delivery was the mode of delivery for 58% of the neonates, while 42% were delivered via Caesarean section (Table 3).

Birth Weight: The majority of the study population had a birth weight between 1.00 and 2.49 kg, with 34% weighing between 1.00 and 1.49 kg and 32% weighing between 1.5 and 1.99 kg. 29% weighed between 2.00 and 2.49 kg, and 5% weighed less than 1 kg (Table 4).

Silverman Anderson Score: At the time of enrolment, 32% of the neonates had a Silverman Anderson score between 3 and 5, indicating moderate respiratory distress, while 68% had a score greater than 5, indicating severe respiratory distress (Table 5).

Duration and Complications of i-CPAP Therapy The duration of i-CPAP therapy varied among the neonates (Table 6). The majority (76%) received CPAP for less than 7 days, 14% for 7 to 14 days, and 10% for more than 14 days.Complications associated with i-CPAP therapy were relatively low (Table 7). Nasal injury was observed in 4% of the study population, while no cases of pneumothorax were reported. The majority (96%) of neonates experienced no complications during i-CPAP therapy.

Outcomes of i-CPAP TherapThe outcomes of the study population following i-CPAP therapy are presented in Table 8. Overall, 42% of the neonates were successfully weaned to room air with oxygen supplementation, 21% continued on BCPAP (likely as a step-down therapy or due to persistent mild respiratory support needs), and 37% required escalation to mechanical ventilation.

Gestational Age and Outcome Table 9 shows the distribution of outcomes based on gestational age. None of the neonates born at less than 28 weeks were weaned successfully; all required either continued CPAP or ventilation. In the 28-32 weeks gestational age group, 26% were weaned, 72.4% experienced CPAP failure, and 1.6% were not accounted for in these categories. In the 32-36 weeks group, a higher proportion (74%) were weaned, and a lower proportion (19%) experienced CPAP failure (Chi-square test= 30.88, p=0.0001*, statistically significant).

Mode of Delivery and Outcome The relationship between the mode of delivery and outcome is shown in Table 10. Among neonates delivered via normal vaginal delivery, 69% were weaned, and 26% experienced CPAP failure. In contrast, among those delivered via Caesarean section, only 31% were weaned, and 74% experienced CPAP failure (Chi-square test= 18.25, p=0.0001*, statistically significant).

Silverman Anderson Score and Outcome Table 11 explores the association between the initial Silverman Anderson score and outcome. Among neonates with a score of 3-5, 86% were extubated (weaned), and 16% experienced CPAP failure. For those with a score >5, only 14% were extubated, while 84% experienced CPAP failure (Chi-square test= 4.01, p=0.03*, statistically significant).

Birth Weight and Outcome Table 12 details the neonatal outcomes based on birth weight and CPAP. Neonates with a birth weight of <1 kg had no successful extubation. For those weighing 1-1.49 kg, 11.9% were extubated, and 50% experienced CPAP failure. In the 1.5-1.99 kg group, 31% were extubated, and 32.8% experienced CPAP failure. The highest extubation success (57.1%) was observed in neonates weighing 2-2.5 kg, with only 8.6% experiencing CPAP failure (Chi-square test= 13.14, p=0.001*, statistically significant).

Surfactant Administration and Outcome The impact of surfactant administration on outcomes is presented in Table 13. Among neonates who received surfactant, 55% were extubated, and 48% experienced CPAP failure. For those who did not receive surfactant, 45% were extubated, and 52% experienced CPAP failure (Chi-square test= 0.40, p=0.52, Not statistically significant).

Septic Screen and Outcome Table 14 shows the outcomes based on the results of the septic screen. Among neonates with a positive septic screen, 31% were extubated, and 45% experienced CPAP failure. For those with a negative septic screen, 69% were extubated, and 55% experienced CPAP failure (Chi-square test= 1.95, p=0.16, Not statistically significant).

This prospective study evaluated the clinical profile and outcome of preterm babies with RDS treated with indigenously assembled CPAP in a tertiary care NICU. The findings highlight several important aspects of i-CPAP use in this population. The study population predominantly consisted of neonates born between 28 and 32 weeks of gestation, which is consistent with the known incidence of RDS being higher in more premature infants. The slight male predominance observed is also in line with some reference studies in neonatal research. The distribution of birth weights indicated that a significant proportion of the neonates fell into the very low birth weight (VLBW) and low birth weight (LBW) categories, which are known risk factors for RDS and poorer outcomes.

The majority of neonates in this study received i-CPAP for less than 7 days, suggesting that early intervention with CPAP can be effective in stabilizing many infants with RDS. The low complication rate associated with i-CPAP, with nasal injury being the most common but infrequent complication, underscores the relative safety of this mode of respiratory support when administered with appropriate monitoring and care.

The overall outcomes revealed that a significant proportion (42%) of neonates were successfully weaned to room air with oxygen supplementation following i-CPAP therapy, indicating its effectiveness in managing RDS in a substantial number of cases. However, a considerable proportion (37%) required escalation to mechanical ventilation, highlighting the severity of RDS in some infants and the limitations of CPAP in such cases. The 21% who continued on BCPAP likely represent those with milder RDS or those requiring a gradual weaning process.

The study found a statistically significant correlation between gestational age and outcome, with more mature preterm infants (32-36 weeks) having a higher success rate with i-CPAP compared to those born earlier (<32 weeks). This is consistent with existing literature suggesting better outcomes with CPAP in infants with increasing gestational age and maturing lung function. Similarly, neonates delivered via normal vaginal delivery had a significantly higher rate of successful weaning compared to those delivered by Caesarean section. This could be attributed to the physiological benefits of labour and vaginal delivery in preparing the lungs for extrauterine life.

The initial severity of respiratory distress, as indicated by the Silverman Anderson score, also significantly impacted the outcome. Neonates with moderate RDS (score 3-5) had a much higher rate of successful weaning compared to those with severe RDS (score >5), emphasizing the importance of early CPAP initiation before the establishment of severe lung injury. Birth weight also showed a significant association with outcome, with higher birth weight categories associated with greater success in weaning from i-CPAP.

Interestingly, surfactant administration and the presence of a positive septic screen did not show statistically significant associations with the outcome of i-CPAP therapy in this study. This could be due to various factors, including the timing and criteria for surfactant administration and the overlap between RDS and early-onset sepsis in preterm infants. Further investigation with larger sample sizes and more detailed stratification might be needed to clarify these relationships.

The findings of this study are consistent with the broader literature supporting the role of CPAP as a crucial intervention in the management of RDS in preterm infants, especially in resource-limited settings where cost-effectiveness and accessibility of equipment are important considerations. The relatively low complication rate and significant success in weaning highlight the potential of indigenously assembled CPAP systems to provide effective respiratory support.

Summary

This study evaluated the clinical profile and outcome of preterm babies with RDS treated with i-CPAP in a tertiary care NICU. The key findings include:

• The majority of the study population were preterm infants born between 28 and 32 weeks of gestation with low birth weights.
• i-CPAP was used for a duration of less than 7 days in most cases.
• Complication rates were low, with nasal injury being the most common.
• A significant proportion of neonates were successfully weaned to room air with oxygen supplementation.
• Gestational age, mode of delivery, and initial severity of respiratory distress (Silverman Anderson score) were significantly associated with the outcome of i-CPAP therapy.
• Birth weight also significantly influenced the outcome.
• Surfactant administration and septic screen results did not show a statistically significant association with i-CPAP outcome in this cohort.

Recommendations

Based on the findings of this study, the following recommendations can be made:

1. Early CPAP Support: Early initiation of i-CPAP in preterm infants with RDS, particularly those with moderate respiratory distress, is crucial for better outcomes.
2. Prevention of Nasal Injury: Vigilant monitoring and appropriate selection of nasal prongs or interfaces, along with the use of moisturisers and hydrocolloid dressings, are essential to prevent nasal injury during CPAP therapy.
3. Targeted Respiratory Support Strategies: Respiratory support strategies should be tailored based on gestational age, birth weight, and the severity of RDS. Infants with lower gestational ages and birth weights, and those with severe initial respiratory distress, may require closer monitoring and a lower threshold for escalation to mechanical ventilation.
4. Further Research: Further studies with larger sample sizes are needed to explore the role of surfactant administration and sepsis in the outcomes of i-CPAP therapy in preterm infants with RDS. Comparative studies between indigenous and commercially available CPAP systems would also be valuable in optimizing respiratory support in resource-limited settings.
5. Continuous Monitoring and Evaluation: Continuous monitoring of clinical parameters and outcomes of i-CPAP use is essential to ensure its effectiveness and safety in routine clinical practice.

Risk factors other than smoking, notably Biomass fuel This study reaffirms the critical role of indigenously assembled CPAP therapy in managing respiratory distress syndrome in preterm neonates, particularly those born with low birth weights. The findings are consistent with reference studies, demonstrating that i-CPAP is a safe and effective non-invasive respiratory support modality in a tertiary care setting. The significant associations observed between gestational age, mode of delivery, initial disease severity, birth weight, and the outcome of i-CPAP highlight the importance of considering these factors in the clinical management of preterm infants with RDS. The study contributes valuable insights into the use of i-CPAP in a resource-limited environment and underscores its potential to improve neonatal outcomes.

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