Clinical outcome of preterm babies managed for respiratory distress syndrome using nasal continuous positive airway pressure and surfactant: An experience from Ile-Ife, South-Western Nigeria

EA Adejuyigbe; Osagie Joseph Ugowe; Chineme Henry Anyabolu; Toluwani Ebun Babalola

doi:10.4103/jcn.jcn_27_22

ORIGINAL ARTICLE

Year : 2022 | Volume : 11 | Issue : 2 | Page : 112-116

Clinical outcome of preterm babies managed for respiratory distress syndrome using nasal continuous positive airway pressure and surfactant: An experience from Ile-Ife, South-Western Nigeria

EA Adejuyigbe¹, Osagie Joseph Ugowe², Chineme Henry Anyabolu³, Toluwani Ebun Babalola²
¹ Department of Paediatrics, Neonatal Unit, Obafemi Awolowo University Teaching Hospitals Complex; Department of Paediatrics and Child Health, Obafemi Awolowo University, Ile-Ife, Nigeria
² Department of Paediatrics and Child Health, Obafemi Awolowo University, Ile-Ife, Nigeria
³ Department of Paediatrics, Paediatric Gastroenterology Unit, Obafemi Awolowo University Teaching Hospitals Complex; Department of Paediatrics and Child Health, Obafemi Awolowo University, Ile-Ife, Nigeria

Date of Submission	03-Mar-2022
Date of Decision	17-Mar-2022
Date of Acceptance	18-Mar-2022
Date of Web Publication	20-Apr-2022

Correspondence Address:
Osagie Joseph Ugowe
Department of Paediatrics and Child Health, Obafemi Awolowo University, Ile-Ife
Nigeria

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jcn.jcn_27_22

Abstract

Background: Respiratory distress syndrome (RDS) is a common cause of morbidity and mortality among preterm babies. It is caused by a deficiency of surfactant; hence, there is reduced lung compliance and increased work of breathing. The use of continuous positive airway pressure (CPAP) ventilation, a noninvasive form of ventilation, as well as the administration of exogenous surfactant, has proven to be very useful in the management of RDS. The use of less invasive techniques in ventilation and administration of surfactant have also been shown to reduce the risk of bronchopulmonary dysplasia and adverse effect of intubation. Objective: The objective is to determine mean oxygen saturation at 1 h, 6 h, and 12 h after commencement of CPAP, the mean values of FiO₂ and positive end-expiratory pressure before and after administration of surfactant, and the overall case-fatality rate and birth weight-specific mortality rates. Methods: Study design was a prospective observational study and subjects were inborn babies between 26 and 34 weeks gestation who were managed for RDS with CPAP alone or with additional surfactant. Results: All 104 recruited preterm babies were managed with CPAP. Fifty-six (53.8%) babies also had surfactant administered. The mean weight of the babies was 1.35 (±0.322) kg, and the mean gestational age was 30.95 (±2.24) weeks. Extremely low birth weight (ELBW), very low birth weight (VLBW), and LBW constituted 11.5%, 55.8%, and 32.7% of the study population, respectively. The mean SPO₂ before CPAP and 12 h after were 90.93 (±5.39) % and 96.5 (±3.30) %, respectively. The overall case-fatality rate was 18.2%, and birth-weight-specific mortality rates for ELBW, VLBW, and LBW were 58.3%, 15.5%, and 9.7%, respectively. Conclusion: From this study, it is clear that the prompt use of a cost-effective CPAP devices and the administration of surfactant are very effective in reducing morbidity and mortality among VLBW babies. While most local studies focused on the experience with the use of CPAP alone, this study goes further to demonstrate that the use of CPAP and surfactant is more effective in the management of RDS.

Keywords: Bubble-continuous positive airway pressure, minimally invasive surfactant administration, outcome, respiratory distress syndrome

How to cite this article:
Adejuyigbe E A, Ugowe OJ, Anyabolu CH, Babalola TE. Clinical outcome of preterm babies managed for respiratory distress syndrome using nasal continuous positive airway pressure and surfactant: An experience from Ile-Ife, South-Western Nigeria. J Clin Neonatol 2022;11:112-6

How to cite this URL:
Adejuyigbe E A, Ugowe OJ, Anyabolu CH, Babalola TE. Clinical outcome of preterm babies managed for respiratory distress syndrome using nasal continuous positive airway pressure and surfactant: An experience from Ile-Ife, South-Western Nigeria. J Clin Neonatol [serial online] 2022 [cited 2023 Mar 21];11:112-6. Available from: https://www.jcnonweb.com/text.asp?2022/11/2/112/343423

Introduction

Respiratory distress syndrome (RDS) is the most common disorder of premature infants, and it contributes largely to the morbidity and mortality of this “fragile” group of babies.^[1] Prematurity contributes as much as 25% of neonatal mortality.^[2] More infants die due to RDS in low-resource countries compared to developed nations. These deaths may even occur in larger premature infants.^[1] RDS is due to deficiency in surfactant seen in premature babies^[3] This deficiency causes an increase in surface tension which tends to make the alveoli collapse on expiration. Subsequently, there is decreased lung volume and compliance.^[3],[4] Clinical state may worsen due to poor oxygenation in the first 48 h.^[4] The gold standard in its treatment is the use of positive pressure ventilation through continuous positive airway pressure (CPAP) or mechanical ventilation and administration of exogenous surfactant.^[5] Classic radiological findings of “ground glass appearance and air bronchograms” are rarely seen due to the early institution of management.^[5]

However, over the years, the management of RDS in preterm babies in low-resource settings has largely been with the use of 100% oxygen which can lead to retinopathy of prematurity and bronchopulmonary dysplasia.^[1],[6] Furthermore, due to the unavailability of facilities, mortality rates have been relatively high, especially among the very low birth weight (VLBW) and extremely low birth weight (ELBW) babies.^[1],[6] Recently, attempts at mitigating these challenges have been with the use of improvised “bubble” CPAP devices.^[6],[7] However, a recent survey showed that the use of CPAP, whether patented or improvised, was mostly in tertiary hospitals and patented machines were available only in one-third of the 57 health facilities that participated in the survey.^[8] Similar challenges existed in our newborn unit in Ile-Ife, but with the acquisition of nasal CPAP and surfactant, the unit developed a protocol for the management of babies with RDS. All preterm babies with features of RDS are commenced on nasal CPAP, and the administration of surfactant is then considered based on the clinical assessment of increased oxygen requirement.

This study is unique because it reports the effectiveness of nasal CPAP and surfactant among premature babies that fall mostly in the ELBW and VLBW categories. The study was therefore undertaken to examine the clinical outcome of 104 preterm neonates delivered at the Ife Hospital Unit of the Obafemi Awolowo University Teaching Hospitals Complex (OAUTHC) and managed for RDS. All babies recruited were born at gestational age of 26–34 weeks, where the risk of developing RDS is high. The specific objectives were to determine: (i) mean oxygen saturation at 1 h, 6 h, and at 12 h after commencing CPAP, (ii) the mean values of FiO₂ and positive end-expiratory pressure (PEEP) before and after administration of surfactant, (iii) the overall case fatality rate and birth weight-specific mortality rates.

Methods

This prospective observational study was carried out at the Neonatal ward, Ife Hospital Unit of the OAUTHC, Ile-Ife, Osun State-Nigeria from January 2019 to May 2020. All consecutive preterm babies delivered at the OAUTHC were recruited at birth, and all babies with gestational age above 34 weeks who were delivered during the study were excluded. Nasal CPAP is instituted as an initial respiratory support for spontaneously breathing preterm babies suspected to have RDS as part of the routine unit protocol. The CPAP manufactured by Diamedica (UK), built as a modified oxygen concentrator that supplies blended humidified oxygen (maximum oxygen flow: 8 L/min, maximum airflow: 8 L/min) as well as continuous positive pressure ventilation.^{[9],[10],[11]}

Immediately after resuscitation at birth, babies are moved into the neonatal unit where CPAP is commenced at FiO₂ of 0.5 with a PEEP of 5 cm H₂O. Babies without spontaneous respiratory effort at birth are commenced on bag and mask ventilation (with the option of endotracheal tube insertion). On resumption of spontaneous ventilation, such babies are commenced promptly on CPAP. If any baby requires a FiO₂ more than 0.5 to maintain oxygen saturation above 90%, the baby is then administered surfactant immediately and continued on CPAP. The less invasive surfactant administration or minimally invasive surfactant therapy technique using a size-6 or 8 feeding tube is improvised as a tracheal catheter and surfactant is administered under direct laryngoscopy. The SPO₂ is recorded at 1 h, 6 h, and 12 h after commencing CPAP. The FiO₂ is stepped down daily with a saturation of 90%–95% as the goal. Temperature is usually maintained between 36.5°C and 37.5°C. Babies are weaned off CPAP when optimal saturation is maintained at the least FiO₂.

Data collected include APGAR scores at 1 and 5 min, birth weight, gestational age, and mean SPO₂ at 1 h, 6 h, and 12 h. The mean gestational age was determined using Modified Ballard score and LMP. Weight was subclassified into ELBW, VLBW, and low birth weight (LBW). The median admission and CPAP duration in days were also determined. T-test was used to compare the mean weights and gestational age of babies who received CPAP alone and babies who received both CPAP and surfactant as well as the SPO₂ and FiO₂ of both the groups. Mortality rates of the babies in the different weight categories were compared using Chi-Square or likelihood ratio, and P < 0.05 was considered statistically significant.

Results

A total of 1180 babies were admitted to the neonatal unit of our hospital between January 2019 and May 2020. The total number of preterm babies admitted during this period was 206 (17.4%). One hundred and two babies were excluded because they were above 34 weeks of gestation. One hundred and four babies were therefore recruited into the study with a F:M ratio of 1.2:1. Eighty-six (82.7%) of the babies were delivered by cesarean section, while 18 (17.3%) were vaginal deliveries. The gestational age ranged from 26 to 34 weeks with a mean standard deviation (SD) gestational age of 30.95 (±2.24) weeks. The birth weight of the babies studied ranged from 0.7 kg to 2.18 kg with a mean (SD) of 1.35 (±0.322) kg. Twelve babies (11.5%) were in the ELBW category, while 58 (55.8%) and 34 (32.7%) babies were in the VLBW and LBW categories.

All 104 babies had CPAP administered at birth as they all showed signs of RDS. A total of 56 (53.8%) of the babies had surfactant administered in addition to the use of CPAP, while 48 (46.2%) had CPAP alone. The mean (SD) oxygen saturation of the babies before the commencement of CPAP was 90.93 (±5.39) %. Comparatively, the mean oxygen saturation value after CPAP was commenced was 95.7 (±2.26), 96.4 (±2.23) %, and 96.5 (±3.30) % at 1 h, 6 h, and 12 h, respectively. The median interquartile range duration of CPAP use (CPAP days) was 5.0 (2.0–7.0) days, while the median duration of admission was 18.0 (10.0–30.0) days.

[Table 1] shows that the mean (SD) gestational age for the babies whose RDS was managed with surfactant and CPAP was 30.0 (±1.82) weeks compared with the mean (SD) gestational age for babies managed with CPAP alone which was 32.12 (±2.11) weeks. This difference was statistically significant [Table 1]. The mean (SD) birth weight of the babies managed with CPAP and surfactant was 1.28 (±0.30) kg, while it was 1.43 (±0.33) kg for babies managed with CPAP alone. [Table 1] also shows that the difference in the mean duration of CPAP therapy for babies managed with CPAP alone and babies managed with both CPAP and surfactant was not statistically significant (t = 1.891; P = 0.065).

Table 1: Comparison of the mean birth weight, gestational age, and mean duration of continuous positive airway pressure therapy for babies managed with continuous positive airway pressure alone/continuous positive airway pressure with surfactant therapy

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The mean values of vital parameters used in assessing the improvement in clinical condition while on CPAP are shown in [Table 2]. The mean SPO₂ values before and 12 h after surfactant administration were 89.35 (±5.52) % and 96.10 (±4.08) % respectively (8.015; P < 0.001). There were reductions in mean FiO₂ and PEEP to 0.31 (±0.21) and 2.97 (±2.41) cm H₂O respectively after surfactant administration with P < 0.05.

Table 2: Mean oxygen saturation, fraction of inspired oxygen, and positive end-expiratory pressure before and after surfactant administration

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Six (5.8%) and 12 (11.5%) of the 104 recruited babies had suspected intraventricular hemorrhage and necrotizing enterocolitis, respectively. Nineteen babies died, giving an overall case fatality rate of 18.3% [Table 3]. Six (31.5%) of the cases of mortality had suspected intraventricular hemorrhage and two (10.5%) had necrotizing enterocolitis diagnosed before death. Of the 19 preterm babies that died, 7 (36.8%) were ELBW while 9 (47.4%) and 3 (15.8%) were VLBW and LBW babies, respectively. [Table 3] shows the weight-specific mortality rates. The ELBW category had the highest mortality rate of 58.3% while babies weighing 1–1.49 kg had a 15.5% mortality rate (χ² = 15.22; P = 0.0005). Fourteen (73.7%) of the babies who died had surfactant administered. The mean (SD) APGAR scores of the babies that died were 5.2 (±2.26) compared to a mean of 6.5 (±1.22) recorded among babies that were alive and discharged (t = −5.99; P = 0.95).

Table 3: Birth weight-specific mortality rates

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Discussion

This study has shown that early management with CPAP and exogenous surfactant improves the outcome of VLBW infants.^[12] About 67.3% of the preterm babies recruited in this study were very low and ELBW. These categories of preterm babies constitute a high-risk group, and previous studies around Nigeria have demonstrated higher mortality rates, especially in the absence of assisted ventilation and surfactant replacement.^[13] The birth weight-specific mortality rates for ELBW and VLBW babies in the present study were 58.3% and 15.5%, respectively. These figures were lower than mortality rates of 83.8% and 39.3% found by Owa et al. in Ilesa,^[13] 70.6% and 31.7% reported by Oluwafemi and Abiodun^[14] in Akure, both in south-western Nigeria, and a mortality rate of 80% and 41%, respectively, found by Chidiebere et al. in Enugu.^[15] Our findings were comparable to that of Ntuli et al.,^[16] in South Africa where birth weight specific mortality was 48.0% for ELBW and 16.3% for VLBW and babies with RDS were managed with CPAP, surfactant, and mechanical ventilation.

The use of CPAP is more beneficial to the preterm babies with RDS than 100% oxygen, which is still widely used in Nigeria due to the unavailability of facilities. The PEEP provided by the CPAP machine prevents the alveoli from collapsing at expiration.^[17] The nasal CPAP used in this study is an oxygen-concentrator CPAP which is cost-effective because it is powered by electricity, and oxygen cylinders are not needed for oxygen supply.^[11] Surfactant was administered only to babies that needed increased oxygen (FiO₂ >0.5) to maintain a normal oxygen saturation.^[18] This was found to be more cost-effective than prophylactic administration of surfactant and suits a low-income country like ours where resources are scarce and cost of treatment is relatively high. In addition, other studies have shown that prophylactic surfactant is not superior to selective therapy in terms of neonatal outcome.^[12],[19]

The technique of surfactant administration employed for this study was the less invasive or minimally invasive technique. Using this method, a catheter is needed to administer the surfactant under direct laryngoscopy while the oxygen saturation is being monitored. The risk of apnea is reduced because CPAP can still be administered while the procedure is ongoing. Furthermore, the risk of trauma to the airway with the use of endotracheal tubes can be minimized using a less invasive method.^[18] An added benefit is that there is less concern about getting appropriate-size endotracheal tubes, especially for the ELBW babies.^[18]

In our study, the mean birth weight and gestational age of the preterm babies that had surfactant and CPAP were 1.28 kg and 30 weeks, respectively, compared with mean values of 1.42 kg and 32 weeks for babies managed with CPAP alone. This was very similar to the findings of Arora et al.^[20] where the mean weight and GA were 1.32 kg and 30 weeks for babies that had CPAP and surfactant and 1.46 kg and 31 weeks, respectively, for babies on only nasal CPAP. This shows that the lower weight and gestational age groups of preterm babies require surfactant replacement compared to babies with higher gestational ages and weights. Unlike the Arora et al.'s^[20] study where mechanical ventilators were used after administering surfactant, we do not possess mechanical ventilators in our unit. This limits the level of respiratory support that can be rendered to preterm babies with RDS and depressed respiratory patterns.

The relevant parameters that clearly demonstrated the effectiveness of CPAP and surfactant from this study were the increase in mean oxygen saturation at 1 h, 6 h, and 12 h after commencement of CPAP, the significantly lower mean FiO₂ and PEEP of babies that had surfactant administered compared to babies that were managed with CPAP alone. The increase in mean SPO₂ was also reported by the Ezenwa et al.^[6] and Audu et al.^[7] studies, even though improvised bubble CPAPs were used. The improvised bubble CPAP, though useful in a resource-poor setting, is associated with increased risk of bronchopulmonary dysplasia, as 100% oxygen is often used.^[21] From our findings, the mean duration of CPAP use was 5 days, shorter than the prolonged periods of oxygen use, which was the previous practice in our unit before the CPAP machines were acquired. Lower PEEP and FiO2 were recorded after commencement of surfactant in our study, with similar findings by Bao et al.^[22]

Conclusion

Although the use of CPAP alone can reduce mortality among VLBW infants, this study has shown that less invasive administration of exogenous surfactant can provide better outcomes, especially in the VLBW babies. However, the cost of acquiring these resources remains a limitation that exists in many of our centers across the country. Efforts must be geared towards this direction so that clinicians can intervene and reduce neonatal morbidity and mortality. The major limitation of this study was the unavailability of mechanical ventilators which may have improved the chances of survival of the ELBW babies.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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