Journal List > Allergy Asthma Respir Dis > v.4(6) > 1059221

Jeong, Hwang, Kwon, Shin, Kwon, Han, Seo, and Choung: Prediction of the severity and length of hospital stay in infants with acute bronchiolitis using the severity score



This study aimed to evaluate the clinical factors that could influence the length of hospital stay (LHS) of infants with acute bronchiolitis using the bronchiolitis severity score (BSS).


The medical records of 105 infants aged 0–12 months with acute bronchiolitis who were admitted to a tertiary hospital between December 2014 and May 2015 were reviewed. The BSS was composed 5 factors, namely general condition, wheezing, chest retraction, respiration rate, and peripheral oxygen saturation, which were evaluated at admission. In addition, the age of the infants, LHS, body weight, birth history, familial history, laboratory test result, chest X-ray, and treatment modalities were reviewed. Subjects were classified into 3 groups according to their BSS, and logistic regression analysis was used to identify the association of the BSS with longer LHS.


Among subjects, 62 were studied. Their mean LHS and age were 5.5±2.0 days and 3.9±2.7 months, respectively. Twelve infants were classified as mild (20.3%), 43 as moderate (68.8%), and 7 as severe (10.9%). Venous blood gas pH value and white blood cell count were the best predictors of disease severity. The LHS was associated with the BSS, age, body weight and pCO2 by venous blood gas analysis (P<0.05).


The LHS was associated with the BSS, age, body weight, and pCO2 by venous blood gas analysis at admission. The BSS could be a useful tool to predict disease severity and decide treatment strategies for infants with acute bronchiolitis who have no known risk factors.

Figures and Tables

Fig. 1

Percentage of oxygen therapy and use of systemic corticosteroid in each groups by bronchial severity score (BSS). BSS: mild, 0–5; moderate, 6–10; severe, >10.

Table 1

Bronchiolitis severity score (BSS)8

Clinical index Score
0 1 2 3
General appearance Quite, sleeping Crying when touched, but easy to console Moderately irritable, difficult to console Extremely irritable, lethargic, poor feeing
Wheezing No crepitation, no wheezing Diffuse crepitation or terminal expiratory wheezing Entire expiratory wheezing Diffuse inspiratory wheezing with or without expiratory wheezing
Chest retraction None Mild, intercostal retraction Moderate, sternal retraction Severe (severe retraction with nasal flaring)
Respiratory rate (per min) < 40 40–55 56–65 > 65
SpO2 (%) > 96 93–95 90–92 < 90

SpO2, peripheral oxygen saturation.

BSS: mild, 0–5; moderate, 6–10; severe, >10.

Table 2

Demographic characteristics of the subjects (n=62)

Characteristic Value
Age (mo) 3.9±2.7
Boys 43 (69.4)
Body weight at birth (kg) 3.3±0.4
Body weight at admission (kg) 7.1±1.9
Height (cm) 63.9±7.3
Use of systemic corticosteroid treatment 33 (53.2)
Duration of steroid treatment (day) 5.0±2.0
Oxygen therapy 27 (43.6)
Duration of oxygen therapy (day) 3.7±2.2

Values are presented as mean±standard deviation or number (%).

Table 3

Demographic characteristics of 3 groups by bronchiolitis severity score (BSS)

Characteristic Group
Mild (n = 12) Moderate (n = 43) Severe (n = 7)
Age (mo) 4.6 ± 3.1 3.8 ± 2.6 3.5 ± 2.1
Boys 7 (58.3) 30 (69.8) 5 (71.4)
Body weight at birth (kg) 3.1 ± 0.4 3.3 ± 0.4 3.5 ± 0.2
Body weight at admission (kg) 7.4 ± 1.9 7.1 ± 1.9 7.2 ± 1.7
Height (cm) 64.0 ± 6.7 63.8 ± 7.4 64.3 ± 7.0
Use of systemic corticosteroid treatment 1 (8.3) 26 (60.5) 6 (85.7)
Oxygen therapy 1 (8.3) 20 (46.5) 6 (85.7)

Values are presented as mean±standard deviation or number (%).

BSS: mild, 0–5; moderate, 6–10; severe, >10.

Table 4

Comparison of clinical characteristics between mild, moderate, and severe group

Characteristic BSS group P-value
Mild and moderate (n = 55) Severe (n = 7)
Hospital length of stay (day) 5.3 ± 1.9 7.1 ± 2.2 0.02*
Age (mo) 4.0 ± 2.7 3.5 ± 2.3 0.66
Body weight at birth (kg) 3.2 ± 0.4 3.5 ± 0.2 0.15
Body weight at admission (kg) 7.1 ± 1.9 7.2 ± 1.9 0.91
Height (cm) 63.8 ± 7.4 64.3 ± 7.5 0.88
VBGA pH 7.35 ± 0.03 7.32 ± 0.05 0.01*
VBGA pCO2 (mmHg) 44.4 ± 7.4 47.2 ± 10.4 0.36
WBC (/µL) 9,395.8 ± 3,335.3 13,992.9 ± 7,249.2 0.01*
CRP (mg/dL) 0.6 ± 1.0 0.6 ± 0.6 0.98

Values are presented as mean±standard deviation.

BSS, bronchiolitis severity score; VBGA, venous blood gas analysis; pCO2, partial pressure of carbon dioxide; WBC, white blood cell count; CRP, C-reactive protein.

BSS: mild and moderate, ≤10; severe, >10.


Table 5

Comparison of clinical characteristics between groups sorted by hospital length of stay

Characteristic Hospital length of stay (day) P-value
<7 (n=47) ≥7 (n=15)
BSS 7.1 ± 2.2 9.0 ± 2.2 0.01*
Age (mo) 4.4 ± 2.6 2.5 ± 2.4 0.02*
Bodyweight at birth (kg) 3.2 ± 0.4 3.4 ± 0.4 0.12
Bodyweight at admission (kg) 7.4 ± 1.7 6.3 ± 2.1 0.04*
Height (cm) 64.9 ± 7.2 60.9 ± 7.1 0.07
VBGA pH 7.35 ± 0.04 7.33 ± 0.02 0.06
VBGA pCO2 (mmHg) 43.0 ± 5.6 49.8 ± 11.0 < 0.01*
WBC (/µL) 10,254.7 ± 4,430.0 8,850.0 ± 2,953.0 0.26
CRP (mg/dL) 0.6 ± 1.0 0.5 ± 0.8 0.62

Values are presented as mean±standard deviation.

BSS, bronchiolitis severity score; VBGA, venous blood gas analysis; pCO2, partial pressure of carbon dioxide; WBC, white blood cell count; CRP, C-reactive protein.

BSS: mild and moderate, ≤10; severe, >10.



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