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Turk Arch Pediatr
Turk Arch Pediatr
Turkish Archives of Pediatrics
2757-6256
Turkish Pediatrics Association

10.5152/TurkArchPediatr.2024.24149
tap-59-5-494
Original Article
Respiratory Syncytial Virus Infections in Pediatric Intensive Care: Association of Sociodemographic Data and Clinical Outcomes with Viral and Bacterial Co-infections
Koçoğlu Barlas Ülkem 1http://orcid.org/0000-0001-7445-5858

Akçay Nihal 2http://orcid.org/0000-0002-8273-2226

Telhan Leyla 3http://orcid.org/0000-0003-0037-7636

Kanğın Murat 3http://orcid.org/0000-0003-0042-0569

Umur Özge 4http://orcid.org/0000-0002-5541-2171

Çıtak Agop 4http://orcid.org/0000-0002-5108-3913

Ceren Tuğrul Hazal 5http://orcid.org/0000-0003-4990-0408

Erdoğan Seher 5http://orcid.org/0000-0002-3393-3363

Menentoğlu Mehmet Emin 6http://orcid.org/0000-0003-3839-4722

Şevketoğlu Esra 6http://orcid.org/0000-0002-8330-2877

Duyu Muhterem 7http://orcid.org/0000-0001-7892-2927

Boydağ Güvenç Kübra 8http://orcid.org/0000-0003-3881-6980

Yusuf Can Yaşar 8http://orcid.org/0000-0002-1767-1551

Türkoğlu Batuhan 2http://orcid.org/0009-0004-3031-5748

1 Department of Pediatrics, Pediatric Intensivist, Istanbul Medeniyet University Faculty of Medicine, Goztepe Prof Dr Suleyman Yalcın City Hospital, Pediatric Intensive Care Unit, İstanbul, Türkiye
2 Department of Pediatrics, University of Health Sciences Türkiye, Kanuni Sultan Suleyman Training and Research Hospital, Pediatric Intensive Care Unit, İstanbul, Türkiye
3 Pediatric Intensivist, Istanbul Medipol University, Bagcilar Mega Hospital, Pediatric Intensive Care Unit, İstanbul, Türkiye
4 Pediatric Intensivist, Acıbadem Mehmet Ali Aydınlar University, Atakent Hospital, Pediatric Intensive Care Unit, İstanbul, Türkiye
5 Department of Pediatrics, Fellow of Pediatric Intensive Care, University of Health Sciences Türkiye, Umraniye Training and Research Hospital, Pediatric Intensive Care Unit, İstanbul, Türkiye
6 Department of Pediatric Intensive Care, Pediatric Intensivist, University of Health Sciences Türkiye, Bakirkoy Dr Sadi Konuk Training and Research Hospital, İstanbul, Türkiye
7 Associated Professor of Pediatric Intensive Care, Goztepe Prof Dr Suleyman Yalcın City Hospital, Pediatric Intensive Care Unit, İstanbul, Türkiye
8 Department of Pediatrics, Pediatric Intensivist, University of Health Sciences Türkiye, Sancaktepe Sehit Prof Dr Ilhan Varank Training and Research Hospital, Pediatric Intensive Care Unit, İstanbul, Türkiye
Corresponding author:Ülkem Koçoğlu Barlas ક ulkemkocoglu@yahoo.com
Cite this article as: Koçoğlu Barlas Ü, Akçay N, Telhan L, et al. Respiratory syncytial virus infections in pediatric intensive care: Association of sociodemographic data and clinical outcomes with viral and bacterial co-infections. Turk Arch Pediatr. 2024;59(5):494-500 .

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https://creativecommons.org/licenses/by-nc/4.0/ Content of this journal is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

Objective:

The aim of the study was to evaluate respiratory syncytial virus (RSV) infections in cases followed in the pediatric intensive care unit (PICU).

Materials and Methods:

The study was designed as a prospective cohort in 6 PICUs. There were 3 groups: only RSV (+), RSV (v+) who were positive for another viral agent(s) in addition to RSV, and RSV (b+) who were positive for a bacterial agent(s) in addition to RSV.

Results:

A total of 119 cases were included in the study, 67 (56.3%) of whom were male. The RSV (+) group had a lower pH compared to the other groups and a higher rate of acute bronchiolitis/bronchitis diagnoses compared to the RSV (v+) group. The RSV (v+) group had higher bicarbonate levels, higher creatinine levels, longer hospital stays, and higher Pediatric Risk of Mortality-3 scores (PRISM-3) compared to the RSV (+) group. Cases with RSV (b+) were younger and also had lower body weight compared to the other groups. Furthermore, the RSV (b+) group had higher C-reactive protein and Procalcitonin (PCT) levels and higher rates of High Flow Nasal Cannula-Oxygen Therapy (HFNC-OT) use. Multiple linear regression analysis revealed that PRISM-3 score, PCT levels, Pediatric Acute Respiratory Distress Syndrome diagnoses, inhaled steroid use, chronic illness status, and heart rate on admission were associated with the length of stay in the PICU.

Conclusion:

High flow nasal cannula-oxygen therapy continues to be the most frequently preferred respiratory support method in RSV infections. Viral infections accompanying RSV can increase the severity of the disease.

Keywords

Co-infections,
intensive care,
pediatric,
respiratory syncytial virus
This study received no funding.
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pmcWhat is already known on this topic?

Respiratory syncytial virus infections are very common in the pediatric age group.

The most common RSV infections are related to the respiratory system.

Children with underlying chronic diseases are particularly at risk for RSV infections.

What this study adds on this topic?

HFNC-OT continues to be the most frequently preferred respiratory support method in RSV infections.

The study revealed that the PRISM-3 score and PCT levels exhibited the most prominent effect on PICU length of stay.

The association of RSV with other viral agents can increase the severity of the disease.

The association of RSV with bacterial agents can lead to an increase in acute phase reactants.

Introduction

Respiratory syncytial virus (RSV) is a single-stranded RNA virus classified under the Orthopneumovirus genus within the Pneumoviridae family. It is recognized as the predominant causative agent of lower respiratory tract infections (LRTIs) in children under 2 years of age and is a significant cause of hospital admissions in developed nations.1,2 Globally, RSV is implicated in an estimated 600 000 deaths annually.3 Respiratory syncytial virus bronchiolitis is particularly noted for its substantial contribution to childhood morbidity and mortality.4 The clinical severity of RSV infection is exacerbated in the presence of underlying conditions such as prematurity, low birth weight, congenital heart disease, immunodeficiency, and Down syndrome.5 Approximately 22% of children with RSV infection necessitate intensive care management in a pediatric intensive care unit (PICU).6

The onset of the coronavirus disease 2019 (COVID-19) pandemic and the subsequent implementation of stringent infection control measures resulted in significant alterations in the incidence of RSV and other respiratory viral infections. Comparatively, RSV infection rates plummeted by 98% in Australia and 94% in Wales during this period.7,8 Similar reductions were observed in RSV-related hospital admissions in Italy and in RSV-related PICU admissions in Latin America.9,10 Conversely, post-pandemic, a substantial surge in RSV-related emergency department visits was reported in numerous countries, particularly Austria.11-13 Initially, this increase was attributed to diminished RSV-specific immunity; however, subsequent research redirected focus toward the differences between new and pre-existing genotypes and their varying pathogenic potentials.14

In March 2022, the Republic of Türkiye Ministry of Health declared the end of the pandemic and subsequently relaxed protective measures.15 The current study aims to evaluate RSV-positive (RSV (+)) cases managed in the PICU during 2023, assessing them in terms of demographic, clinical, laboratory, and therapeutic parameters. Furthermore, the study seeks to compare these RSV (+) cases with those exhibiting concomitant viral or bacterial co-infections and to identify factors influencing the duration of PICU admissions.

Materials and Methods

Study Design

The study was conducted as a multicenter, prospective-cohort study of RSV (+) cases managed in the PICU from January 1, 2023, to December 31, 2023. Six PICUs were included in the study, and ethical approval was obtained from the Istanbul Medeniyet University, Goztepe Training and Research Hospital Ethics Committee (Decision No-Date: 2022/0749-21.12.2022). Throughout the study period, the principles of the Declaration of Helsinki were adhered to and written informed consent was obtained from participants or their parents prior to the study. The inclusion criteria of the study were as follows: age between 1 month and 18 years, admission to the PICU for acute respiratory failure (ARF), detection of RSV (+) in the respiratory pathogen panel (RPP) from a nasopharyngeal swab sample collected within the first 24 hours of PICU admission, and detection of either an additional viral agent or a bacterial agent in the RPP alongside RSV (+). On the other hand, the exclusion criteria included cases with insufficient data and cases with both viral and bacterial co-infections detected simultaneously in the RPP alongside RSV (+). The diagnosis of ARF was based on a combination of clinical and laboratory criteria.16

Respiratory Pathogen Panel

Nasopharyngeal swab samples were analyzed using the Bio-speedy® (Bioeksen, Türkiye) kit with a multiplex real-time polymerase chain reaction (PCR) method on the CFX96 Touch (BioRad Laboratories, Mannheim, Germany) device. This test is capable of detecting parainfluenza virus types 1, 2, 3, and 4, human rhinovirus/enterovirus (HRV/EV), RSV A/B, human bocavirus (HBoV), human parechovirus, human adenovirus (HAdV), human metapneumovirus (HMPV), influenza A/B, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), human coronavirus types 229E/OC43/NL63/HKU1, Mycoplasma pneumoniae, Bordetella pertussis (B. pertussis), Legionella pneumophila, Chlamydia pneumoniae, Haemophilus influenzae (H. influenzae), and Streptococcus pneumoniae (S. pneumoniae).

Data Collection

The demographic data of the cases, the month of PICU admission, the number of days of PICU and hospital stays, Pediatric Risk of Mortality-3 score (PRISM-3), diagnoses of acute and chronic diseases, presence of Pediatric Acute Respiratory Distress Syndrome (PARDS), presenting complaints, vital signs at admission, blood gas parameters, blood count parameters, biochemical markers, viral and bacterial co-infections, maximum respiratory support, treatments, and discharge-mortality status were recorded. Culture results during PICU follow-up were not examined. For the respiratory support methods, there was no protocol between participating centers. The cases were divided into 3 groups as follows: cases with only RSV (+), cases with RSV (+) and additional viral agent(s) (RSV (v+)), and cases with RSV (+) and bacterial agent(s) (RSV (b+)). Comparisons were made between these 3 groups.

Statistical Analysis

In this research, data analysis was conducted using the Statistical Package of Social Science (SPSS) version 20.0 (IBM Corp., Armonk, NY, USA) and the R software (version 4.3.3). The normality of numerical variables was assessed using the Shapiro-Wilk and Kolmogorov-Smirnov tests. Summary statistics for normally distributed numerical variables were presented using the mean ± SD, whereas for variables deviating from normality, the median with the interquartile range (IQR) was reported. Categorical variables were summarized using frequency and percentage values. Various statistical techniques were employed to detect potential group differences, utilizing Pearson’s chi-square test or Fisher’s exact test for categorical variables based on expected cell frequencies. The Kruskal-Wallis H test was utilized in the absence of a normal distribution. Pairwise comparisons were conducted using the pairwise Wilcoxon test for numerical data and the pairwise Pearson’s chi-square test or Fisher’s exact test for categorical data. P-values were adjusted using the Bonferroni correction. To identify factors influencing the length of stay in the PICU, a multiple linear regression analysis was employed using the stepwise method. The following assumptions of multiple linear regression were investigated: linearity, independence, homoscedasticity, normality, and no multicollinearity. All analyses were performed at a 95% confidence level, with a significance level of 0.05.

Results

The study started with 127 cases but continued with 119 cases: 52 (43.7%) were females and 67 (56.3%) were males. The demographic characteristics of all cases, acute disease diagnoses and chronic disease status, presenting symptoms on admission, vital parameters on admission, blood gas and laboratory parameters on admission, maximum respiratory supports, medical treatments during PICU stay, and discharge-mortality status of the cases are presented in Table 1. Among cases with underlying chronic diseases, the top 3 conditions were neurological disorders (17, 35.4%), prematurity (11, 22.9%), and congenital heart diseases (8, 16.6%).

In Figure 1, the distribution of PICU admissions of cases diagnosed with RSV by month is illustrated. According to the findings, the highest rates of PICU admissions occurred in November (31.1%) and December (30.3%).

Within the scope of the study, cases were categorized into 3 groups (Table 2). The RSV (+) group had a significantly lower pH compared to the RSV (b+) group and the RSV (v+) group (P = .019, p = 0.049, respectively). Cases with RSV (+) had a significantly higher rate of acute bronchiolitis/bronchitis (58.2%) compared to those with RSV (v+) (P = .002). The RSV (v+) group had significantly higher bicarbonate levels (P = .005), higher creatinine levels (P = .007), longer hospital stays (P = .001), and higher PRISM-3 scores (P = .003) compared to the RSV (+) group.

Cases with RSV (b+) were significantly younger compared to those in the RSV (+) group (P = .017), and the RSV (v+) group (P = .001). Those with RSV (b+) also had significantly lower body weight compared to the RSV (+) group (P = .020), and the RSV (v+) group (P = .024). Additionally, the RSV (b+) group had a significantly higher RR compared to the RSV (v+) group (P = .020). Furthermore, the RSV (b+) group had significantly higher PCT levels compared to the RSV (+) group and the RSV (v+) group (P = 0.028, P = .042, respectively). The RSV (b+) group had significantly higher CRP (P = .017). Cases with RSV (b+) had a significantly lower rate of chronic illness compared to those with RSV (v+) (P = .029).

Regarding respiratory support, the RSV (+) group required lower rates of COT compared to the RSV (v+) group (P = .028), while the RSV (b+) group had higher rates of HFNC use compared to the RSV (+) group (P = .041).

The univariate analysis revealed several variables significantly associated with the length of stay in the PICU (Table 3). Notably, age, weight, height, some of the acute illness diagnoses (acute renal failure and respiratory arrest), chronic illness, PRISM-3 score, RR, HR, pH, and IMV use were all significantly associated with the outcome, with P-values less than .05. To investigate the interaction effect of variables, the multiple linear regression method was used (Table 4). In the multiple regression analysis, the coefficient for PRISM-3 was 1.116, indicating that each unit increase in the PRISM-3 score was associated with an increase of 1.116 days in the length of stay in the PICU. The coefficient for PCT (mg/L) was −0.148, suggesting that each unit increase in PCT corresponds to a decrease of 0.148 days in the length of stay in the PICU, reflecting an inverse relationship. The presence of PARDS was associated with an increase of 11.654 days in the length of stay. The use of inhaled steroids was associated with a reduction of 6.543 days in the length of stay. Chronic illness had a coefficient of 4.019, meaning that the presence of a chronic illness was associated with an increase of 4.019 days in the length of stay. Finally, the coefficient for HR was 0.120, signifying that each additional beat per minute was related to a 0.120-day increase in the length of stay, reflecting a positive association.

Discussion

Similar to the literature, a male predominance (56.3%) was observed in the study.17 This is attributed in some publications to anatomical differences between the sexes and in others to hormonal changes.18,19 The most common clinical presentations in all cases were acute bronchiolitis/bronchitis and bronchopneumonia/pneumonia (48.8% and 47.9%, respectively). The literature reports that RSV infections commonly present as acute bronchiolitis and less frequently as pneumonia.20 RSV infections are known to be more frequent and severe in children with underlying chronic conditions. A retrospective study in Canada found that 29.8% of 181 pediatric cases had at least one underlying chronic condition, while a study in Switzerland involving children under 3 years of age reported this in 23% of cases.21,22 In our study, this rate was higher (40.3%), though the types of comorbid conditions were similar (neurological disorders (35.4%), prematurity (22.9%), and congenital heart diseases (16.6%)).23

The monthly distribution of RSV-related intensive care admissions varies depending on the geographical location of the countries. In Istanbul, where this study was conducted, summers are typically hot and dry, while winters are rainy and mild. The most frequent admissions occurred in November and December (31.1% and 30.3%, respectively), with no admissions during the summer months (Figure 1). A study in the United States found that the majority of admissions occurred between November and March, while a similar study in Greece reported that the RSV epidemic started in December, peaked in February, and ended in April.24,25 Outbreaks in winter months in temperate climates have been linked to the association of cold weather with RSV activity.26,27

The incidence of PARDS in our study was 8.4%. This is higher compared to a recent study investigating HRV/EV cases.28 In a comparative study of 2 viruses within the same family, the incidence of PARDS in the RSV group was similar to that in the HMP group (20% and 23%, respectively).29 This can be explained by the theory of viral infection-related PARDS, which arises from congenital or acquired immune system disorders and mutations in certain genes.30,31 In the study, HFNC-OT was the most frequently used respiratory support method, applied in 55.5% of cases. The increasing use of high flow nasal cannula-oxygen therapy (HFNC-OT) in recent years has been documented in studies from different countries.32,33 Although its use is recommended, particularly in inpatient pediatric wards, it is not yet widespread in our country. Previous studies have reported the need for IMV in 2% of children with RSV bronchiolitis. However, due to the specific patient population and the high rate of chronic diseases in our study, the IMV usage rate was found to be higher (24.4%).34

Viral and bacterial respiratory pathogens independently increase the secretion in the respiratory tract, thereby raising the likelihood of co-infection.35 In the study, cases in the RSV (v+) group had longer hospital stays, higher PRISM-3 scores, and higher initial creatinine levels compared to the RSV (+) group. The elevated initial creatinine levels are likely a physiological effect associated with the older age of this group.36 The PRISM-3 score was used to assess disease severity, and the higher scores in this group suggest that co-existing viral infections can increase the severity of the disease. This finding contrasts with some studies in the literature. Cebey-Lopez et al. did not find an increase in disease severity in children with dual RSV-Rhinovirus infection.37 Tang et al. reported that viral co-infection did not increase disease severity but could be associated with higher PCT levels.38 Although the relationship between viruses and bacteria is not fully clear, some studies suggest that bacterial co-infection is associated with more severe disease and poorer prognosis.39 Our RSV (b+) cases had lower weights, higher respiratory rates at admission, and higher CRP and PCT levels. Haemophilus influenzae and S. pneumoniae were the most frequently detected agents in nasopharyngeal aspirate samples from these cases. Especially in early childhood, RSV infection is most frequently seen with S. pneumoniae, requiring longer IMV support.40,41

In our study, we found that the length of PICU stay was associated with PRISM-3 score, presence of PARDS, presence of chronic disease, and HR at admission with a positive correlation and PCT levels and inhaled steroid use with a negative correlation. Given that the PRISM-3 score is related to disease severity, it is understandable that these patients required longer intensive care follow-up. However, the inverse relationship between PCT level and length of PICU stay was difficult to interpret. It is possible that the higher use of antibiotics in the RSV (b+) group, where PCT levels were elevated, may have reduced the need for intensive care by making treatment feasible in regular pediatric wards.

The overall mortality rate was 7.6%, with rates of 5.1% in the RSV (+) group, 15% in the RSV (v+) group, and 10% in the RSV (b+) group. In the study by Kang et al. including 92 cases, a 30-day mortality rate of 7.6%, with 5.4% of deaths attributed to severe RSV infection, was reported.42 While our rates are similar, we could not attribute all deaths to RSV as we did not include culture results during intensive care follow-up.

Our study had several limitations. First of all, the RPP did not differentiate between RSV subtypes and evaluated RSV infections as RSV A/B. Secondly, culture results from the intensive care follow-up were not considered. Additionally, the definition of viral and bacterial co-infection did not include additional inflammatory markers, radiological findings, or culture results; the presence of viral and bacterial agents was accepted as co-infection.

Conclusion

In conclusion, this study found that HFNC-OT remains the most frequently used respiratory support method in the intensive care management of RSV infections. The presence of viral co-infections alongside RSV can increase disease severity, leading to longer hospital stays. In contrast, bacterial co-infections elevate acute phase reactant levels more significantly. It is important to pay attention to metabolic parameters during blood gas analysis in RSV-infected patients. While patients with high PRISM-3 scores require longer intensive care stays, those with high PCT levels may not need prolonged intensive care. Further studies with larger sample sizes are needed to support our findings.

Figure 1. Distributions of cases by month.

Table 1. General Characteristics of the Cases in Terms of Demographics, Clinical, Laboratory, and Treatment Methods

Variables		n = 119	
Age (month), median (IQR)		5 (17)	
Weight (kg), median (IQR)		7 (5)	
Height (cm), median (IQR)		65 (22.3)	
Gender, n (%)	Female	52 (43.7)	
Male	67 (56.3)	
PICU stay (day), median (IQR)		6 (7)	
Hospital stay (day), median (IQR)		10 (9)	
PRISM-3, median (IQR)		7 (6)	
Acute illness, n (%)	Acute bronchiolitis/bronchitis	58 (48.8)	
Bronchopneumonia/pneumonia	57 (47.9)	
Acute bronchitis + pneumonia	2 (1.7)	
Acute renal failure	1 (0.8)	
Respiratory arrest	1 (0.8)	
Chronic illness, n (%)		48 (40.3)	
PARDS, n (%)		10 (8.4)	
Presenting symptoms, n (%)	Respiratory distress	114 (95.8)	
Cough	98 (82.4)	
Weakness	67 (56.3)	
Fever	47 (39.5)	
Vomiting	13 (10.9)	
Change in consciousness	13 (10.9)	
Convulsion	11 (9.2)	
Vital parameters	RR (beats/min), median (IQR)	50 (19)	
HR (beats/min), mean ± SD	152.8 ± 21.8	
Blood gas parameters	pH, median (IQR)	7.3 (0.2)	
pCO2 (mmHg), median (IQR)	45 (13.9)	
HCO3 (mmol/L), median (IQR)	22 (4)	
Lactate (mmol/L), median (IQR)	1.7 (1.6)	
Laboratory parameters	White blood cell × 103 /μL, mean ± SD	10.7 ± 4.6	
Lymphocyte × 103 /μL, median (IQR)	3.1 (2.7)	
Creatinine (mg/dL), median (IQR)	0.2 (0.2)	
CRP (mg/L), median (IQR)	10 (28.4)	
PCT (mg/L), median (IQR)	0.2 (0.7)	
Respiratory supports, n (%)	COT	46 (38.7)	
HFNC	66 (55.5)	
NIV	20 (16.8)	
IMV	29 (24.4)	
Treatments, n (%)	Antibiotics	100 (84)	
Steroids	74 (62.2)	
Inhaled beta agonist	86 (72.3)	
Inhaled anticholinergics	72 (60.5)	
Inhaled steroids	96 (80.7)	
Magnesium sulfate	24 (20.2)	
Mortality, n (%)	Exitus	9 (7.6)	
Discharge	110 (92.4)	
COT, continuous oxygen therapy; CRP, C-reactive protein ; HCO3, bicarbonate; HFNC, high-flow nasal cannula; HR, heart rate; IMV, invasive mechanical ventilation; NIV, non-invasive ventilation; PARDS, pediatric acute respiratory distress syndrome; pCO2, partial pressure of carbon dioxide pressure; PCT, procalcitonin; PICU, pediatric intensive care unit; PRISM-3, pediatric risk of mortality score-3; RR, respiratory rate; SpO2, peripheral oxygen saturation.

Table 2. Comparison of Demographic and Clinical Characteristics Between Groups

Variables		RSV (+) (n = 79)	RSV (+) & Viral Co-Infection (n = 20)	RSV (+) & Bacterial Co-Infection (n = 20)	P	
Age (month), median (IQR)		5 (18)	15 (39.5)	2 (5)	.002*a	
Weight (kg), median (IQR)		7 (6)	8 (6)	5 (4)	.026*a	
Height (cm), median (IQR)		65 (22)	74 (31)	60 (12)	.090a	
Gender, n (%)	Female	29 (36.7)	11 (55)	12 (60)	.092b	
	Male	50 (63.3)	9 (45)	8 (40)	
PICU stay (day), median (IQR)		5 (6)	8.5 (13.3)	7 (6.7)	.251a	
Hospital stay (day), median (IQR)		8 (7)	20.5 (25.3)	12 (10.2)	.002*a	
PRISM-3, median (IQR)		6 (6.7)	13 (9.5)	5.5 (7.5)	.009*a	
Acute Illness n (%)	Acute bronchiolitis/bronchitis	46 (58.2)	4 (20)	8 (40)	.001*c	
Bronchopneumonia/pneumonia	33 (41.8)	14 (70)	10 (50)	
Acute bronchitis + pneumonia	0 (0)	1 (5)	1 (5)	
Acute renal failure	0 (0)	1 (5)	0 (0)	
Respiratory arrest	0 (0)	0 (0)	1 (5)	
Chronic illness, n (%)		31 (39.2)	13 (65)	4 (20)	.014*b	
PARDS, n (%)		7 (8.9)	2 (10)	1 (5)	.999c	
Vital parameters, median (IQR)	RR (beats/min)	50 (15)	43.5 (20.7)	57.5 (16.3)	.047*a	
HR (beats/min)	155 (24.5)	152.5 (16.2)	164.5 (28)	.102a	
Blood gas parameters, median (IQR)	pH	7.3 (0.4)	7.4 (0.1)	7.4 (0.1)	.011*a	
pCO2 (mmHg)	45 (13)	44.6 (10.4)	48.1 (15.2)	.804a	
HCO3 (mmol/L)	21 (3)	23.2 (3.2)	22.5 (3.2)	.010*a	
Laktat (mmol/L)	1.7 (1.6)	1.5 (1.1)	1.9 (1.1)	.981a	
Laboratory parameters, median (IQR)	White blood cell ×103 /μL	9.6 (5.5)	12 (9.4)	11.7 (7)	.081a	
Lymphocyte ×103 /μL	3.2 (2.7)	2.6 (3)	2.9 (2.5)	.806a	
Creatinine (mg/dL)	0.2 (0.2)	0.3 (0.1)	0.2 (0)	.006*a	
CRP (mg/L)	9 (32.5)	2.6 (12.9)	22.3 (36)	.040*a	
PCT (mg/L)	0.2 (0.6)	0.1 (0.5)	0.5 (7.6)	.042*a	
Respiratory support, n (%)	COT	25 (31.6)	13 (65)	8 (40)	.024*b	
HFNC	39 (49.4)	11 (55)	16 (80)	.048*b	
NIV d	12 (15.6)	4 (40)	4 (26.7)	.145c	
IMV	16 (20.3)	5 (25)	8 (40)	.187c	
Treatments, n (%)	Antibiotics	64 (81)	17 (85)	19 (95)	.389c	
Steroids	44 (55.7)	16 (80)	14 (70)	.099b	
Inhaled beta-2 agonist	54 (68.4)	16 (80)	16 (80)	.407b	
Inhaled anticholinergics	45 (57)	15 (75)	12 (60)	.337b	
Inhaled steroids	64 (81)	17 (85)	15 (75)	.780c	
Magnesium sulfate	15 (19)	2 (10)	7 (35)	.156c	
					
Mortality, n (%)	Exitus	4 (5.1)	3 (15)	2 (10)	.247c	
Discharge	75 (94.9)	17 (85)	18 (90)	
COT, continuous oxygen therapy; CRP, C-reactive protein; HCO3, bicarbonate; HFNC, high-flow nasal cannula; HR, heart rate; IMV, invasive mechanical ventilation; NIV, non-invasive ventilation; PARDS, pediatric acute respiratory distress syndrome; pCO2, partial pressure of carbon dioxide pressure; PCT, procalcitonin; PICU, pediatric intensive care unit; PRISM-3, pediatric risk of mortality score-3; RR, respiratory rate; SpO2, peripheral oxygen saturation.

*Statistical significance at P < .0. aThe Kruskal–Wallis. bPearson’s chi-square. cFisher’s exact test. dFor the patients that have NIV, there are 77 cases of RSV (+), 10 cases of RSV (v+), and 15 cases of RSV (b+).

Table 3. Factors Affecting Length of Stay in Pediatric Intensive Care Unit (Univariate Linear Regression Analysis)

	Coefficients	Std. Error	P	
Age (month)	0.34	0.06	.000	
Weight (kg)	1.56	0.25	.000	
Height (cm)	0.48	0.11	.000	
Acute renal failure	76.43	13.63	.000	
Respiratory arrest	208.43	13.63	.000	
Chronic illness	12.62	4.38	.005	
PRISM-3	1.35	0.27	.000	
RR (beats/min)	−0.42	0.16	.009	
HR (beats/min)	−0.30	0.10	.003	
Ph	30.33	14.24	.035	
IMV	20.25	4.83	.000	
HR, heart rate; IMV, invasive mechanical ventilation; PRISM-3, pediatric risk of mortality score-3; RR, respiratory rate.

Table 4. Factors Affecting Length of Stay in Pediatric Intensive Care Unit (Multiple Regression Analysis)

	Coefficients	Std. Error	P	
PRISM-3	1.116	0.132	<.001	
PCT (mg/L)	−0.148	0.024	<.001	
PARDS	11.654	2.662	<.001	
Inhaled steroids	−6.543	1.957	.002	
Chronic illness	4.019	1.611	.016	
HR (beats/min)	0.120	0.054	.032	
HR, heart rate; PARDS, pediatric acute respiratory distress syndrome; PCT, procalcitonin; PRISM-3, pediatric risk of mortality score-3.

Ethics Committee Approval: This study was approved by the Ethics Committee of Istanbul Medeniyet University, Goztepe Training and Research Hospital (approval no: 2022/0749, date: December21, 2022).

Informed Consent: Written informed consent was obtained from the cases who agreed to take part in the study.

Peer-review: Externally peer-reviewed.

Author Contributions: Concept – Ü.K.B., N.A.; Design – L.T., M.K.; Supervision – M.D., B.T.; Resources – M.E.M., E.Ş.; Materials – Ö.U., A.Ç.; Data Collection and/or Processing – H.C.T., S.E.; Analysis and/or Interpretation – K.B.G., Y.Y.C.; Literature Search – L.T., N.A.; Writing – Ü.K.B., M.E.M.; Critical Review – E.Ş., H.C.T.

Declaration of Interests: The authors declare that there is no conflict of interest.
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