Relationship of Viral Detection with Duration of Ventilation in Critically Ill Infants with Lower Respiratory Tract Infection

Systematic Literature Review of Respiratory Syncytial Virus Laboratory Testing Practices and Incidence in United States Infants and Children <5 Years of Age

Background

Respiratory syncytial virus (RSV) can cause serious illness in those aged <5 years in the United States, but uncertainty remains around which populations receive RSV testing. We conducted a systematic literature review of RSV testing patterns in studies published from 2000 to 2021.

Methods

Studies of RSV, medically attended RSV lower respiratory tract infections (LRTIs), and bronchiolitis were identified using standard methodology. Outcomes were clinical decisions to test for RSV, testing frequency, and testing incidence proportions in inpatient (IP), emergency department (ED), outpatient (OP), and urgent care settings.

Results

Eighty good-/fair-quality studies, which reported data from the period 1988–2020, were identified. Twenty-seven described the clinical decision to test, which varied across and within settings. Two studies reported RSV testing frequency for multiple settings, with higher testing proportions in IP (n = 2, range: 83%–85%, 1996–2009) compared with ED (n = 1, 25%, 2006–2009) and OP (n = 2, 15%–25%, 1996–2009). Higher RSV testing incidence proportions were observed among LRTI infant populations in the ED (n = 1, 74%, 2007–2008) and OP (n = 2, 54%–69%, 1995–2008). Incidence proportions in LRTI populations were not consistently higher in the IP setting (n = 13). Across studies and time, there was heterogeneity in RSV testing patterns, which may reflect varying detection methods, populations, locations, time periods, and healthcare settings.

Conclusions

Not all infants and children with LRTI are tested for RSV, highlighting underestimation of RSV burden across all settings.

Mortality Among US Infants and Children Under 5 Years of Age with Respiratory Syncytial Virus and Bronchiolitis: A Systematic Literature Review

Background

A systematic literature review was conducted to summarize the mortality (overall and by disease severity factors) of US infants and children aged <5 years with respiratory syncytial virus (RSV) or all-cause bronchiolitis (ACB).

Methods

Comprehensive, systematic literature searches were conducted; articles were screened using prespecified eligibility criteria. A standard risk of bias tool was used to evaluate studies. Mortality was extracted as the rate per 100 000 or the case fatality ratio (CFR; proportion of deaths among RSV/ACB cases).

Results

Among 42 included studies, 36 evaluated inpatient deaths; 10 used nationally representative populations updated through 2013, and only 2 included late-preterm/full-term otherwise healthy infants and children. The RSV/ACB definition varied across studies (multiple International Classification of Diseases [ICD] codes; laboratory confirmation); no study reported systematic testing for RSV. No studies reported RSV mortality rates, while 3 studies provided ACB mortality rates (0.57–9.4 per 100 000). CFRs ranged from 0% to 1.7% for RSV (n = 15) and from 0% to 0.17% for ACB (n = 6); higher CFRs were reported among premature, intensive care unit-admitted, and publicly insured infants and children.

Conclusions

RSV mortality reported among US infants and children is variable. Current, nationally representative estimates are needed for otherwise healthy, late-preterm to full-term infants and children.

Derivation and Validation of the Critical Bronchiolitis Score for the PICU

OBJECTIVES

To derive and internally validate a bronchiolitis-specific illness severity score (the Critical Bronchiolitis Score) that out-performs mortality-based illness severity scores (e.g., Pediatric Risk of Mortality) in measuring expected duration of respiratory support and PICU length of stay for critically ill children with bronchiolitis.

DESIGN

Retrospective database study using the Virtual Pediatric Systems (VPS, LLC; Los Angeles, CA) database.

SETTING

One-hundred twenty-eight North-American PICUs.

PATIENTS

Fourteen-thousand four-hundred seven children less than 2 years old admitted to a contributing PICU with primary diagnosis of bronchiolitis and use of ICU-level respiratory support (defined as high-flow nasal cannula, noninvasive ventilation, invasive mechanical ventilation, or negative pressure ventilation) at 12 hours after PICU admission.

INTERVENTIONS

Patient-level variables available at 12 hours from PICU admission, duration of ICU-level respiratory support, and PICU length of stay data were extracted for analysis. After randomly dividing the cohort into derivation and validation groups, patient-level variables that were significantly associated with the study outcomes were selected in a stepwise backward fashion for inclusion in the final score. Score performance in the validation cohort was assessed using root mean squared error and mean absolute error, and performance was compared with that of existing PICU illness severity scores.

MEASUREMENTS AND MAIN RESULTS

Twelve commonly available patient-level variables were included in the Critical Bronchiolitis Score. Outcomes calculated with the score were similar to actual outcomes in the validation cohort. The Critical Bronchiolitis Score demonstrated a statistically significantly stronger association with duration of ICU-level respiratory support and PICU length of stay than mortality-based scores as measured by root mean squared error and mean absolute error.

CONCLUSIONS

The Critical Bronchiolitis Score performed better than PICU mortality-based scores in measuring expected duration of ICU-level respiratory support and ICU length of stay. This score may have utility to enrich interventional trials and adjust for illness severity in observational studies in this very common PICU condition.