Specific Viral Etiologies Are Associated With Outcomes in Pediatric Acute Respiratory Distress Syndrome

The Common Cold and Influenza in Children: To Treat or Not to Treat?

The common cold, which is mostly caused by respiratory viruses and clinically represented by the symptoms of acute respiratory viral infections (ARVI) with mainly upper respiratory tract involvement, is an important problem in pediatric practice. Due to the high prevalence, socio-economic burden, and lack of effective prevention measures (except for influenza and, partially, RSV infection), ARVI require strong medical attention. The purpose of this descriptive literature review was to analyze the current practical approaches to the treatment of ARVI to facilitate the choice of therapy in routine practice. This descriptive overview includes information on the causative agents of ARVI. Special attention is paid to the role of interferon gamma as a cytokine with antiviral and immunomodulatory effects on the pathogenesis of ARVI. Modern approaches to the treatment of ARVI, including antiviral, pathogenesis-directed and symptomatic therapy are presented. The emphasis is on the use of antibody-based drugs in the immunoprophylaxis and immunotherapy of ARVI. The data presented in this review allow us to conclude that a modern, balanced and evidence-based approach to the choice of ARVI treatment in children should be used in clinical practice. The published results of clinical trials and systematic reviews with meta-analyses of ARVI in children allow us to conclude that it is possible and expedient to use broad-spectrum antiviral drugs in complex therapy. This approach can provide an adequate response of the child’s immune system to the virus without limiting the clinical possibilities of using only symptomatic therapy.

Pathobiology, Severity, and Risk Stratification of Pediatric Acute Respiratory Distress Syndrome: From the Second Pediatric Acute Lung Injury Consensus Conference

OBJECTIVES

To review the literature for studies published in children on the pathobiology, severity, and risk stratification of pediatric acute respiratory distress syndrome (PARDS) with the intent of guiding current medical practice and identifying important areas for future research related to severity and risk stratification.

DATA SOURCES

Electronic searches of PubMed and Embase were conducted from 2013 to March 2022 by using a combination of medical subject heading terms and text words to capture the pathobiology, severity, and comorbidities of PARDS.

STUDY SELECTION

We included studies of critically ill patients with PARDS that related to the severity and risk stratification of PARDS using characteristics other than the oxygenation defect. Studies using animal models, adult only, and studies with 10 or fewer children were excluded from our review.

DATA EXTRACTION

Title/abstract review, full-text review, and data extraction using a standardized data collection form.

DATA SYNTHESIS

The Grading of Recommendations Assessment, Development, and Evaluation approach was used to identify and summarize relevant evidence and develop recommendations for clinical practice. There were 192 studies identified for full-text extraction to address the relevant Patient/Intervention/Comparator/Outcome questions. One clinical recommendation was generated related to the use of dead space fraction for risk stratification. In addition, six research statements were generated about the impact of age on acute respiratory distress syndrome pathobiology and outcomes, addressing PARDS heterogeneity using biomarkers to identify subphenotypes and endotypes, and use of standardized ventilator, physiologic, and nonpulmonary organ failure measurements for future research.

CONCLUSIONS

Based on an extensive literature review, we propose clinical management and research recommendations related to characterization and risk stratification of PARDS severity.

Epidemiology and Acute Respiratory Distress Syndrome Propensity of Viral Respiratory Infections in Pediatric Intensive Care Units Prior to the Coronavirus Disease 2019 Pandemic

This study aimed to determine the epidemiology and acute respiratory distress syndrome (ARDS) propensity of common respiratory viruses in a tertiary pediatric intensive care unit (PICU) among hospitalized children who were tested for respiratory viruses by polymerase chain reaction (PCR) prior to the coronavirus disease 2019 (COVID-19) pandemic. Respiratory tract samples were collected from patients who were followed up in the Dokuz Eylul University Hospital pediatric intensive care unit between March 2015 and March 2020 and tested for viral pathogens. The results of 269 patients between 1 month and 18 years of age were evaluated retrospectively. In the 5 years preceding the COVID-19 pandemic, 269 patients with a lower respiratory infection were admitted to the PICU. A positive viral PCR result was detected in 160 patients (59.5%). Human rhinovirus was the most common virus (40%), followed by respiratory syncytial virus (26.3%), human bocavirus (10%), and seasonal coronaviruses (10%). Five (33.3%) of the fifteen children who developed ARDS were infected with influenza A/B, while four (26.7%) were infected with human metapneumovirus (hMPV).Although rhinovirus was the most common viral agent in critically ill children, the incidence of ARDS was higher in children aged over 1 year who had influenza or hMPV infection.

Analysis of predictors of mortality and clinical outcomes of different subphenotypes for moderate-to-severe pediatric acute respiratory distress syndrome: A prospective single-center study

BACKGROUND

This study aimed to observe the prognosis of patients with moderate-to-severe pediatric acute respiratory distress syndrome (PARDS) admitted to the Pediatric Intensive Care Unit (PICU) as a function of underlying conditions and available treatment strategies, and to investigate the risk factors for death and the outcomes of different clinical subphenotypes.

METHODS

Patients were divided into non-survivors and survivors according to the prognosis 28 days after the diagnosis. The risk factors for death and the predictive value of relevant factors for mortality were analyzed. Latent class analysis was used to identify different clinical subphenotypes.

RESULTS

A total of 213 patients with moderate-to-severe PARDS were enrolled, of which 98 (46.0%) died. Higher PELOD2 scores (OR = 1.082, 95% CI 1.004-1.166, p < 0.05), greater organ failure (OR = 1.617, 95% CI 1.130-2.313, p < 0.05), sepsis (OR = 4.234, 95% CI 1.773-10.111, p < 0.05), any comorbidity (OR = 3.437, 95% CI 1.489-7.936, p < 0.05), and higher infiltration area grade (IAG) (OR = 1.980, 95% CI 1.028-3.813, p < 0.05) were associated with higher mortality. The combination of these five indicators had the largest area under the curve (sensitivity 89.79%, specificity 94.78%). Patients were classified into higher-risk and lower-risk phenotype group according to the latent class analysis. Compared to the lower-risk phenotype, more patients with higher-risk phenotype suffered from sepsis (24.40% vs. 12.20%, p < 0.05), inherited metabolic diseases (45.80% vs. 25.60%, p < 0.05), positive respiratory pathogens (48.10% vs. 26.80%, p < 0.05), and higher IAG (p < 0.05); they also had significantly higher PIM3 and PELOD2 scores (p < 0.05), with an extremely high mortality rate (61.1% vs. 22.0%, p < 0.05).

CONCLUSIONS

Moderate-to-severe PARDS has high morbidity and mortality in PICU; a higher PELOD2 score, greater organ failure, sepsis, any comorbidity, and higher IAG were risk factors for death, and the combination of these five indicators had the greatest value in predicting prognosis. More patients with sepsis, positive respiratory pathogens, higher PIM3 and PELOD2 scores, and higher IAG were in higher-risk phenotype group, which had worse outcomes. Clear classification facilitates targeted treatment and prognosis determination.

Application of Multiplex Polymerase Chain Reaction for Pathogen Identification and Antibiotic Use in Children With Respiratory Infections in a PICU

OBJECTIVES

To compare the pathogen identification rate and use of antibiotics before and after the implementation of multiplex polymerase chain reaction testing in children with respiratory infections in a PICU.

DESIGN

Single-center, pre-post study.

SETTING

PICU of Osaka Women's and Children's Hospital, Osaka, Japan.

PATIENTS

Consecutive children with respiratory infections who were admitted to the PICU between December 2017 and November 2018 (premultiplex polymerase chain reaction period) and between March 2019 and February 2020 (postmultiplex polymerase chain reaction period).

INTERVENTIONS

Conventional rapid antigen tests and bacterial culture tests were performed throughout the study period. Multiplex polymerase chain reaction testing using the FilmArray respiratory panel (BioFire Diagnostics, Salt Lake City, UT) was conducted to detect 17 viruses and three bacterial pathogens. During the postmultiplex polymerase chain reaction period, we did not recommend prescribing antibiotics for stable children, depending on the virus species and laboratory test results.

MEASUREMENTS AND MAIN RESULTS

Ninety-six and 85 children were enrolled during the pre- and postmultiplex polymerase chain reaction periods, respectively. Rapid antigen tests identified pathogens in 22% of the children (n = 21) during the premultiplex polymerase chain reaction period, whereas rapid antigen tests and/or multiplex polymerase chain reaction testing identified pathogens in 67% of the children (n = 57) during the postmultiplex polymerase chain reaction period (p < 0.001). The most commonly identified pathogen using multiplex polymerase chain reaction testing was human rhino/enterovirus. Bacterial pathogens were identified in 50% of the children (n = 48) and 60% of the children (n = 51) during the pre- and postmultiplex polymerase chain reaction periods (p = 0.18). There were no differences in antibiotic use (84% vs 75%; p = 0.14), broad-spectrum antibiotic use (33% vs 34%; p = 0.91), or the duration of antibiotic use within 14 days of admission (6.0 vs 7.0 d; p = 0.45) between the pre- and postmultiplex polymerase chain reaction periods.

CONCLUSIONS

Although the pathogen identification rate, especially for viral pathogens, increased using multiplex polymerase chain reaction testing, antibiotic use did not reduce in children with respiratory infections in the PICU. Definitive identification of bacterial pathogens and implementation of evidence-based antimicrobial stewardship programs employing multiplex polymerase chain reaction testing are warranted.

High-Frequency Jet Ventilation in Infants With Congenital Heart Disease

BACKGROUND

High-frequency jet ventilation (HFJV) is primarily used in neonates but may also have a role in the treatment of infants with congenital heart disease and severe respiratory failure. We hypothesized that HFJV would result in improved gas exchange in these infants.

METHODS

We retrospectively reviewed the records of all pediatric patients with complex congenital heart disease treated HFJV in our pediatric cardiac ICU between 2014 and 2018. Patients in whom HFJV was started while on extracorporeal membrane oxygenation (ECMO) were excluded. We extracted data on demographics, pulmonary mechanics, gas exchange, the subsequent need for ECMO, use of inhaled nitric oxide, and outcomes.

RESULTS

We included 27 subjects (median [interquartile range {IQR}] weight 4.4 [3.3-5.4] kg; median [IQR] age 2.5 [0.3-5.4] months), 22 (82%) of whom had cyanotic heart disease. Thirteen subjects (48%) survived and 6 (22%) required ECMO. HFJV was started after a median (IQR) of 8.4 (2.1-26.3) d of conventional mechanical ventilation. The subjects spent a median (IQR) of 1.2 (0.5-2.8) d on HFJV. The median (IQR) pre-HFJV blood gas results (n = 25) were pH 7.22 (7.17-7.31), [Formula: see text] 69 (51-77) mm Hg, and [Formula: see text] 51 (41-76) mm Hg. Median (IQR) initial HFJV settings were peak inspiratory pressure of 45 (36-50) cm H₂O, breathing frequency of 360 (360-380) breaths/min, and inspiratory time of 0.02 (0.02-0.03) s. Compared with conventional mechanical ventilation, at 4-6 h after HFJV initiation, there were significant improvements in the median pH (7.22 vs 7.34; P = .001) and [Formula: see text] (69 vs 50 mm Hg; P = .001), respectively, but no difference in median [Formula: see text] (51 vs 53 mm Hg; P = .97).

CONCLUSIONS

HFJV was associated with a decrease in [Formula: see text] and an increase in pH in infants with congenital heart disease who remained on HFJV 4 to 6 h after initiation.

Influenza Virus Associated Pediatric Acute Respiratory Distress Syndrome: Clinical Characteristics and Outcomes

BACKGROUND AND OBJECTIVE

The aim of this multicenter retrospective study was to determine the clinical characteristics, treatment approaches and the course of pediatric acute respiratory distress syndrome (PARDS) which developed associated with the influenza virus in the 2019-20 season.

METHODS

Patients included 1 month to 18 years who were diagnosed with PARDS associated with the influenza virus in the 2019-20 season.

RESULTS

Sixty-seven patients were included in the study. The mean age of the patients was 64.16 ± 6.53 months, with 60% of the group <5 years. Influenza A was determined in 54 (80.5%) patients and Influenza B in 13 (19.5%). The majority of patients (73.1%) had a comorbidity. Fifty-eight (86.6%) patients were applied with invasive mechanical ventilation, Pediatric Acute Lung Injury Consensus Conference classification was mild in 5 (8.6%), moderate in 22 (37.9%) and severe in 31 (52.5%) patients. Ventilation was applied in the prone position to 40.3% of the patients, and in nonconventional modes to 24.1%. A total of 22 (33%) patients died, of which 4 had been previously healthy. Of the surviving 45 patients, 38 were discharged without support and 7 patients with a new morbidity.

CONCLUSION

Both Influenza A and Influenza B cause severe PARDS with similar characteristics and at high rates. Influenza-related PARDS cause 33% mortality and 15.5% morbidity among the study group. Healthy children, especially those aged younger than 5 years, are also at risk.

High-Frequency Jet Ventilation in Pediatric Acute Respiratory Failure

BACKGROUND

High-frequency jet ventilation (HFJV) is primarily used in premature neonates; however, its use in pediatric patients with acute respiratory failure has been reported. The objective of this study was to evaluate HFJV use in the pediatric critical care setting. We hypothesized that HFJV would be associated with improvements in oxygenation and ventilation.

METHODS

Medical records of all patients who received HFJV in the pediatric ICU of a quaternary care center between 2014 and 2018 were retrospectively reviewed. Premature infants who had not been discharged home were excluded, as were those in whom HFJV was started while on extracorporeal membrane oxygenation. Data on demographics, pulmonary mechanics, gas exchange, and outcomes were extracted and analyzed using chi-square testing for categorical variables, nonparametric testing for continuous variables, and a linear effects model to evaluate gas exchange over time.

RESULTS

A total of 35 subjects (median age = 2.9 months, median weight = 5.2 kg) were included. Prior to HFJV initiation, median (interquartile range) oxygenation index (OI) was 11.3 (7.2-16.9), [Formula: see text] = 133 (91.3-190.0), pH = 7.18 (7.11-7.27), [Formula: see text] = 64 (52-87) mm Hg, and [Formula: see text] = 74 (64-125) mm Hg. For subjects still on HFJV (n = 25), there was no significant change in OI, [Formula: see text], or [Formula: see text] at 4-6 h after initiation, whereas pH increased (P = .001) and [Formula: see text] decreased (P = .001). For those remaining on HFJV for > 72 h (n = 12), the linear effects model revealed no differences over 72 h for OI, [Formula: see text], [Formula: see text], or mean airway pressure, but there was a decrease in [Formula: see text] while pH and [Formula: see text] increased. There were 9 (26%) subjects who did not survive, and nonsurvivors had higher Pediatric Index of Mortality 2 scores (P = .01), were more likely to be immunocompromised (P = .01), were less likely to have a documented infection (P = .02), and had lower airway resistance (P = .02).

CONCLUSIONS

HFJV was associated with improved ventilation among subjects able to remain on HFJV but had no significant effect on oxygenation.

Cytokine Panels and Pediatric Acute Respiratory Distress Syndrome: A Translational Investigation

OBJECTIVES

To identify and compare serum and lower respiratory tract fluid biomarkers of lung injury using well-characterized mouse models of lung injury. To explore the relationship between these preclinical biomarkers and clinical outcomes in a discovery cohort of pediatric patients with acute respiratory failure from pneumonia.

DESIGN

Prospective, observational cohort study.

SETTING

A basic science laboratory and the PICU of a tertiary-care children's hospital.

PATIENTS

PICU patients intubated for respiratory failure from a suspected respiratory infection.

INTERVENTIONS

Prospective enrollment and collection of lower respiratory tract fluid samples.

MEASUREMENTS AND MAIN RESULTS

C57BL6/J mice were intranasally inoculated with escalating doses of influenza A virus or toll-like receptor agonists to simulate varying degrees of lung injury. Serum and bronchoalveolar lavage fluid were measured for the presence of cytokines using commercially available multiplex cytokine assays. Elevated levels of C-C motif chemokine ligand 7 at the peak of inflammation in both bronchoalveolar lavage fluid and serum correlated with lethality, with the bronchoalveolar lavage fluid ratio of C-C motif chemokine ligand 7:C-C motif chemokine ligand 22 providing the best prediction in the mouse models. These preclinical biomarkers were examined in the plasma and lower respiratory tract fluid of a discovery cohort of pediatric patients with acute respiratory failure from pneumonia. The primary clinical outcome measure was ventilator-free days, with secondary outcomes of pediatric acute respiratory distress syndrome severity and mortality. Elevation in peak lower respiratory tract fluid C-C motif chemokine ligand 7:C-C motif chemokine ligand 22 ratios demonstrated a significant negative correlation with ventilator-free days (r = -0.805; p < 0.02).

CONCLUSIONS

This study provides evidence that lung immune profiling via lower respiratory tract fluid cytokine analysis is feasible and may provide insight into clinical outcomes. Further validation of markers, including the C-C motif chemokine ligand 7:C-C motif chemokine ligand 22 ratio in this limited study, in a larger cohort of patients is necessary.

Testing for Common Respiratory Viruses in Children Admitted to Pediatric Intensive Care: Epidemiology and Outcomes

OBJECTIVES

Viral infections are common in children, but there is a lack of data on severe viral infections in critically ill children. We investigated testing for viral infections in children requiring PICU admission and describe the epidemiology and outcomes.

DESIGN

Multicenter retrospective study. Results of viral testing for nine respiratory viruses using polymerase chain reaction were collected.

PARTICIPANTS

Children less than 16 years old nonelectively admitted to PICU over a 6-year period.

SETTING

Two tertiary PICUs in Queensland, Australia.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Primary outcome was PICU length of stay. Secondary outcomes included need for and duration of intubation and mortality in PICU. Univariate and multivariate regression analyses were performed, adjusting for age, indigenous status, comorbidities, and severity of illness.

RESULTS

Of 6,426 nonelective admissions, 2,956 (46%) were polymerase chain reaction tested for a virus of which 1,353 (46%) were virus positive. Respiratory syncytial virus was the most common pathogen identified (n = 518, 33%), followed by rhinovirus/enterovirus and adenovirus. Across all patients who underwent polymerase chain reaction testing, identification of a respiratory virus was not significantly associated with longer overall length of stay (multivariate odds ratio, 1.08; 95% CI, 0.99-1.17; p = 0.068) or longer intubation (p = 0.181), whereas the adjusted odds for intubation and mortality were significantly lower (p < 0.01). Subgroup analyses restricted to patients with acute respiratory infections (n = 1,241), bronchiolitis (n = 761), pneumonia (n = 311), confirmed bacterial infection (n = 345), and malignancy (n = 95) showed that patients positive for a virus on testing had significantly longer PICU length of stay (multivariate p < 0.05). In children with pneumonia, identification of a respiratory virus was associated with significantly increased duration of ventilation (p = 0.003). No association between positive test results for multiple viruses and outcomes was observed.

CONCLUSION

Viral infections are common in critically ill children. Viral infections were associated with lower intubation and mortality rates compared with all children testing negative for viral infections. In several subgroups studied, identification of viral pathogens was associated with longer PICU length of stay while mortality was comparable. Prospective studies are required to determine the benefit of routine testing for respiratory viruses at the time of PICU admission.