Saline Nebulization in Bronchiolitis: Clinical Outcomes in Infants

Interna tional Jo urna l o f Pedia trics a nd Neo na to logy 2025 ; 7 (1 ): 06 -10
ISSN Print: 2664-8350
ISSN Online: 2664-8369
Impact Factor: RJIF 5.26
IJPN 2025; 7(1): 06-10
www.pediatricsjournal.net
Received: 12-04-2025
Accepted: 16-05-2025
Exploring the role of saline nebulization in
bronchiolitis: Clinical recovery, MRDAI scores, and
hospital outcomes
Dr. Mahmuda Khanom
Consultant, Department of
Pediatrics, Hope Maternal and
Child Hospital, Cox’s Bazar,
Bangladesh
Mahmuda Khanom, Probir Kumar Sarkar, KM Ishtiaque Sayeed, Md.
Mahbub Al Amin, Fahmida Ferdous, Ayesha Siddika Tonny and
Farhana Bhuiyan
Dr. Probir Kumar Sarkar
Professor, Department of
Pediatric Respiratory
Medicine, Bangladesh Shishu
Hospital and Institute, Dhaka,
Bangladesh
DOI: https://doi.org/10.33545/26648350.2025.v7.i2a.139
KM Ishtiaque Sayeed
Health Specialist, UNICEF
Bangladesh
Md. Mahbub Al Amin
Assistant Register,
Department of Pediatric
Cardiology, National Institute
of Cardiovascular Disease
(NICVD), Shere E Bangla
Nagar, Dhaka, Bangladesh
Dr. Fahmida Ferdous
Medical Officer, Department of
Pediatrics, Dhaka North City
Corporation Covid-19
Dedicated Hospital, Dhaka,
Bangladesh
Dr. Ayesha Siddika Tonny
Medical Officer, Kurmitola 500
Bed General Hospital, Dhaka,
Bangladesh
Dr. Farhana Bhuiyan
Senior Medical Officer,
Ministry of Labour &
Employment, Dhaka,
Bangladesh
Corresponding Author:
Dr. Mahmuda Khanom
Consultant, Department of
Pediatrics, Hope Maternal and
Child Hospital, Cox’s Bazar,
Bangladesh
Abstract
Background: Respiratory Syncytial Virus (RSV) bronchiolitis is a significant cause of lower
respiratory tract infections in infants, particularly those under two months. Supportive care is the
cornerstone of management. Nebulized normal saline (0.9% sodium chloride) is often used in clinical
practice, sometimes as a control in studies, but its specific impact on this age group warrants detailed
documentation.
Objective: This study aimed to characterize the clinical course, respiratory distress changes, and
hospital outcomes in infants under two months of age with RSV-positive bronchiolitis who received
nebulized normal saline as part of their care.
Methods: This analysis focuses on the control group (Normal Saline-NS) of a randomized controlled
trial, which included 45 infants aged ≤60 days with RSV-positive bronchiolitis. Participants in this
group received nebulized 0.9% normal saline (3ml) every 8 hours. Outcomes assessed included
Modified Respiratory Distress Assessment Instrument (MRDAI) scores, oxygen saturation (SpO₂),
duration of oxygen therapy, and length of hospital stay. Descriptive statistics were used to present the
findings.
Results: The mean age of participants in the NS group was 39.21±1.50 days; 71.11% were male.
MRDAI scores showed a reduction from a baseline of 6.82±1.30 to 2.31±0.13 by Day 4, with a mean
difference of 4.49±1.09. SpO₂ at admission was 91.68±1.70%, and 92.16±0.14% after 24 hours. The
average duration of oxygen therapy was 11.54±1.46 hours. Rapid recovery (within 72 hours) occurred
in 48.8% of cases. The mean hospital stay was 79.64±3.69 hours.
Conclusion: In infants ≤2 months with RSV-positive bronchiolitis, nebulized normal saline
administered as part of supportive care was associated with a gradual improvement in respiratory
distress and clinical recovery. These findings provide a detailed account of outcomes in this patient
group receiving standard supportive management including normal saline nebulization.
Keywords: RSV, bronchiolitis, normal saline, infants, respiratory distress, MRDAI, oxygen therapy,
supportive care
Introduction
Acute bronchiolitis is one of the leading causes of lower respiratory tract infections (LRTIs)
in infants, particularly those under two years of age. Respiratory syncytial virus (RSV) is the
most commonly identified etiologic agent, accounting for up to 70% of bronchiolitis cases
during seasonal epidemics [1]. The condition is characterized by inflammation of the
bronchioles, resulting in airway obstruction, wheezing, hypoxia, and respiratory distress [2].
Despite the high global disease burden, especially in low-and middle-income countries, the
optimal therapeutic approach remains controversial due to a lack of universally effective
pharmacological interventions [3].
Supportive care remains the cornerstone of bronchiolitis management. This typically
includes oxygen supplementation, hydration, and nasal suctioning [4]. Among the supportive
measures, nebulized normal saline (0.9% NaCl) has been increasingly utilized in hospital
settings, especially in resource-constrained environments, as a cost-effective and readily
available option [5].
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The rationale for using nebulized saline lies in its potential
to moisturize the airway, facilitate mucociliary clearance,
and relieve nasal congestion—thereby improving clinical
symptoms such as cough, wheezing, and dyspnea [6].
Although hypertonic saline has received more attention in
the literature for its potential to reduce hospital stay and
severity scores [7], the utility and outcomes of isotonic saline
(normal saline) continue to be explored, particularly in
young infants.
Nebulized normal saline is presumed to act by thinning
mucus secretions and improving airway hydration, thus
reducing airway resistance [8]. Clinical observations have
shown symptomatic improvement in infants administered
with normal saline nebulization, particularly when
bronchodilators are not effective or are contraindicated [9]. In
some trials, infants treated with nebulized normal saline
have shown reductions in respiratory distress scores and
hospital length of stay, although results remain mixed across
different age groups and settings [10].
The Modified Respiratory Distress Assessment Instrument
(MRDAI) is a validated clinical tool frequently employed to
assess the severity of bronchiolitis. It captures respiratory
rate, wheezing, and retractions—parameters that are
particularly responsive to therapies aimed at improving
airway patency and oxygenation [11]. Tracking changes in
MRDAI scores over time can offer insights into the clinical
trajectory and treatment responsiveness in affected infants.
Although several studies have compared normal saline with
other agents like hypertonic saline or bronchodilators, very
few have focused solely on analyzing the efficacy and
outcomes associated with normal saline nebulization [12].
Moreover, radiological and physiological parameters such
as oxygen saturation levels, duration of oxygen therapy, and
total length of hospital stay serve as important indicators of
treatment success. The documentation and analysis of these
parameters can help understand how nebulized normal
saline impacts short-term clinical recovery [13]. It is also
essential to investigate patterns of symptom resolution, such
as feeding ability, apnea, cyanosis, and respiratory rate, to
provide a comprehensive understanding of patient
outcomes.
This study aims to evaluate the clinical recovery,
progression of MRDAI scores, and key hospital outcomes in
RSV-positive infants who received nebulized 0.9% normal
saline as part of their supportive care. By focusing solely on
the normal saline group, the study intends to contribute to
the existing literature by offering granular insights into the
effects of isotonic saline therapy in managing acute
bronchiolitis. Such findings may prove especially relevant
for resource-limited settings where access to more
expensive or specialized treatments may be restricted.
conducted at Dhaka Shishu (Children) Hospital, Dhaka,
between June 2018 and July 2020.
Study Population
The group consisted of 45 infants, aged 0 to 2 months, who
were admitted with a clinical diagnosis of acute
bronchiolitis and had confirmed RSV infection (via
nasopharyngeal swab PCR).
Inclusion Criteria
 Age 0 months to 2 months.
 Both sexes.
 First episode of respiratory distress with wheezing,
preceded by signs of a viral upper respiratory infection
(cough, nasal blockage).
 Confirmed RSV-positive status.
 MRDAI score >3.
 No clinical or laboratory evidence of concomitant
bacterial infection.
Exclusion Criteria
 Age >2 months.
 Previous episodes of wheezing or respiratory distress.
 Diagnosed chronic cardiopulmonary conditions.
 History of neonatal mechanical ventilation.
 Presentation with critical illness or incipient respiratory
failure.
Study Procedure
Infants in this group received nebulization with 3 mL of
0.9% normal saline. The nebulization was administered
every 8 hours daily via a jet nebulizer until the time of
discharge. All patients received standard supportive hospital
care, including oxygen therapy to maintain SpO₂ ≥92%,
intravenous fluids if needed, nutritional support, appropriate
positioning, and oropharyngeal/nasal suctioning as required.
Data Collection
A pre-tested, semi-structured questionnaire was used to
collect demographic information and detailed clinical
history. A thorough physical examination was conducted
upon admission. The Modified Respiratory Distress
Assessment Instrument (MRDAI) was used to assess
clinical severity at admission, at 12 hours after the first
nebulization, and daily thereafter until discharge. Oxygen
saturation (SpO₂) was measured using a pulse oximeter.
Standard laboratory investigations (Hb%, total and
differential leukocyte count) and a chest X-ray (PA view)
were performed at admission. Key outcomes recorded
included the duration of oxygen therapy and the total length
of hospital stay.
Objective
To describe and evaluate the clinical progression, changes in
severity scores (MRDAI), oxygen requirements, and
hospital outcomes in infants up to two months of age with
RSV-positive acute bronchiolitis who received treatment
with nebulized 0.9% normal saline.
Outcome Measures
 Primary Outcomes: Evolution of MRDAI score, rate
of clinical recovery (categorized as rapid or gradual),
duration of oxygen therapy needed, and total length of
hospital stay.
 Secondary Outcomes: Changes observed in respiratory
rate, heart rate (tachycardia), use of accessory
respiratory muscles, presence of cyanosis, auscultatory
findings (such as wheezing or ronchi), and SpO₂ levels.
Methods
Study Design
This analysis focuses on the control group (receiving normal
saline) from a prospective, randomized clinical trial
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Table 1: Demographic Characteristics (NS Group, n = 45)
Statistical Analysis
Data were compiled and analyzed using SPSS version 20.0.
Descriptive statistics (mean±standard deviation for
continuous variables; frequencies and percentages for
categorical variables) were employed to summarize the data.
The chi-square (χ²) test was used for comparing categorical
variables, and an unpaired t-test for continuous variables
where appropriate. A p-value of less than 0.05 was taken to
indicate statistical significance.
Characteristic
Age (in days)±SD
Gender-Male (%)
Gender-Female (%)
Value
39.21±1.50
32 (71.11%)
13 (28.89%)
Clinical Presentations at Admission
The clinical features observed at the time of hospital
admission are summarized in Figure 1. All infants presented
with core symptoms of bronchiolitis, including difficulty in
breathing, cough, wheeze, tachypnoea, chest indrawing,
rhonchi, nasal blockage, and feeding difficulty. Fever and
tachycardia were also commonly observed (93.3%). Less
frequent findings included nasal flaring (22.2%), cyanosis
(26.6%), and apnea (6.6%).
Results
Demographic Characteristics
The demographic profile of the NS group is presented in
Table 1. The mean age of infants was 39.21±1.50 days.
Among the 45 participants, 32 (71.11%) were male, and 13
(28.89%) were female, indicating a predominance of male
infants in the study group.
Fig 1: Clinical Presentations at Admission (NS Group, n = 45)
Radiological Findings on Admission
Radiological evaluation via chest X-ray revealed that the
most common findings were hyperinflation (93.3%) and
hyper-translucency (88.8%), as shown in Table 3.
Atelectasis was identified in 6 infants (13.3%).
baseline (6.82±1.30) to Day 4 (2.31±0.13), indicating
progressive clinical improvement.
Table 2: Radiological Findings on Admission (NS Group, n = 45)
Time Point Mean MRDAI Score±SD
Radiological Finding
Hyperinflation
Hyper translucency
Atelectasis
Frequency (n)
42
40
6
Table 3: MRDAI Score Trend and Mean Differences from
Baseline (NS Group, n = 45)
Baseline
12 Hours
Day 1
Day 2
Day 3
Day 4
Percentage (%)
93.3
88.8
13.3
Treatment Outcomes Based on MRDAI Score
Progression
The Modified Respiratory Distress Assessment Instrument
(MRDAI) scores were used to assess the severity of
respiratory distress at baseline and across subsequent time
points. As shown in Table 4, a steady and statistically
meaningful reduction in MRDAI scores was observed from
6.82±1.30
5.98±0.23
4.87±0.23
3.60±0.21
2.52±0.21
2.31±0.13
Mean Difference from
Baseline±SD
—
0.84±0.30
1.96±0.29
3.22±0.29
4.30±1.21
4.49±1.09
Key Clinical Recovery Indicators
Key clinical recovery indicators, as presented in Table 5,
provide further insight into treatment outcomes. The mean
duration of oxygen therapy was 11.54±1.46 hours. The
mean peripheral oxygen saturation (SpO₂) at admission was
91.68±1.70%, which slightly improved to 92.16±0.14%
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after 24 hours. Regarding recovery dynamics, 48.8% of
infants experienced rapid recovery (within 72 hours), while
51.2% required more than 72 hours. The average length of
hospital stay was 79.64±3.69 hours.
including hyperinflation and hyper-translucency were
common among the NS group, which is consistent with
typical imaging results in bronchiolitis. These findings
further validate the clinical diagnosis and demonstrate that
the study population was representative of standard RSV
bronchiolitis cases [20].
In summary, this study affirms that nebulized 0.9% normal
saline, as part of a supportive care regimen, is associated
with gradual clinical recovery in RSV-positive infants.
While it may not actively hasten resolution, it is a safe,
accessible, and potentially mildly beneficial adjunct to
oxygen and hydration in managing moderate bronchiolitis.
The outcomes presented here serve as a valuable reference
for baseline management and comparison with more active
interventions in future trials.
Table 4: Key Clinical Recovery Indicators (NS Group, n = 45)
Outcome Parameter
Duration of O₂ Therapy (hours)
SpO₂ at Admission (%)
SpO₂ after 24 Hours (%)
Rapid Recovery (<72 hours)
Gradual Recovery (>72 hours)
Length of Hospital Stay (hours)
Value (Mean ± SD/n (%))
11.54±1.46
91.68±1.70
92.16±0.14
22 (48.8%)
23 (51.2%)
79.64±3.69
Discussion
This study evaluated the clinical progression and outcomes
in RSV-positive infants up to two months of age who were
treated with nebulized 0.9% normal saline (NS) as part of
supportive care. The observed gradual decline in the
MRDAI scores over time highlights a progressive clinical
improvement, consistent with the natural course of
bronchiolitis when managed conservatively [14]. With a
baseline MRDAI score of 6.82, the infants demonstrated
moderate respiratory distress upon admission, and
subsequent reductions in scores over four days reflect
alleviation of respiratory effort and symptom burden.
Normal saline nebulization, while not universally
recommended as an active pharmacologic intervention,
plays a role in maintaining airway hydration. It can facilitate
mucociliary clearance and reduce airway obstruction by
thinning secretions [15]. Studies have shown that while
hypertonic saline may provide more pronounced effects due
to its osmotic action, nebulized 0.9% saline still supports the
humidification of airways, a benefit particularly relevant in
infants with bronchiolitis where nasal congestion and mucus
plugging are common [16].
The observed oxygen therapy duration (mean 11.54±1.46
hours) and hospital stay (mean 79.64±3.69 hours) align with
findings from prior research on standard care for
bronchiolitis in infants [17]. This suggests that, although NS
nebulization may not significantly accelerate recovery
compared to more active interventions, it does not
contribute to adverse outcomes either. These findings
reinforce its utility in low-resource or conservative clinical
settings where more advanced treatments may be
unavailable or unnecessary.
Notably, approximately 48.8% of the infants recovered
within 72 hours, while 51.2% required a longer
hospitalization. This split emphasizes the heterogeneity in
disease progression among young infants, possibly
influenced by individual immune responses, viral load, or
co-morbidities, although such variables were not directly
examined in this study. Nevertheless, the improvement trend
confirms that normal saline nebulization, along with other
supportive measures like oxygen and hydration, contributes
to stabilization and gradual improvement in uncomplicated
cases of bronchiolitis [18]. Importantly, no significant adverse
events such as deterioration of oxygen saturation or
increased respiratory distress were noted, supporting the
safety profile of NS in this vulnerable age group. A previous
randomized study also observed no harm associated with NS
nebulization in infants with bronchiolitis, concluding that it
may be used safely when hypertonic saline or
bronchodilators are not preferred [19]. Radiological findings
Conclusion
In this cohort of infants up to 2 months of age with RSVpositive acute bronchiolitis, treatment with nebulized 0.9%
normal saline as part of standard supportive care was
associated with a gradual reduction in clinical severity
scores and a mean hospital stay of approximately 3.3 days.
Clinical recovery within 72 hours was observed in nearly
half of the patients. These findings document the typical
clinical course and outcomes for this vulnerable population
receiving such management and serve as an important
reference for clinical practice and future research.
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How to Cite This Article
Khanom M, Sarkar PK, Sayeed KMI, Amin MMA, Ferdous F, Tonny
AS et al. Exploring the role of saline nebulization in bronchiolitis:
Clinical recovery, MRDAI scores, and hospital outcomes.
International Journal of Pediatrics and Neonatology. 2025;7(1):06-10.
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