Background
High flow nasal cannula (HFNC) systems utilize higher gas flow rates than standard nasal cannulae. The use of HFNC as a respiratory support modality is increasing in the infant, pediatric, ...and adult populations as an alternative to non-invasive positive pressure ventilation.
Objectives
This critical review aims to: (1) appraise available evidence with regard to the utility of HFNC in neonatal, pediatric, and adult patients; (2) review the physiology of HFNC; (3) describe available HFNC systems (online supplement); and (4) review ongoing and planned trials studying the utility of HFNC in various clinical settings.
Results
Clinical neonatal studies are limited to premature infants. Only a few pediatric studies have examined the use of HFNC, with most focusing on this modality for viral bronchiolitis. In critically ill adults, most studies have focused on acute respiratory parameters and short-term physiologic outcomes with limited investigations focusing on clinical outcomes such as duration of therapy and need for escalation of ventilatory support. Current evidence demonstrates that HFNC generates positive airway pressure in most circumstances; however, the predominant mechanism of action in relieving respiratory distress is not well established.
Conclusion
Current evidence suggests that HFNC is well tolerated and may be feasible in a subset of patients who require ventilatory support with non-invasive ventilation. However, HFNC has not been demonstrated to be equivalent or superior to non-invasive positive pressure ventilation, and further studies are needed to identify clinical indications for HFNC in patients with moderate to severe respiratory distress.
Dense ceramics of the pyrochlore (Bi1.5Zn0.5)(Ti1.5Nb0.5)O7 can be prepared at 1100 °C and exhibit a high permittivity (εr = 200) and low dielectric loss (tan δ < 1 × 10−4) at 1 MHz and room ...temperature. In this study, the effect of MgO addition on the phase evolution, sintering behaviour, microstructures and dielectric properties of (Bi1.5Zn0.5)(Ti1.5Nb0.5)O7 (BZTN) ceramics are investigated. The ceramics were sintered in air at temperatures ranging from 850° to 1000 °C. BZTN ceramics with small amount of MgO addition can significantly increase the density and improve the dielectric properties. It is found that MgO doped BZTN ceramics can be sintered at 900 °C to obtain a density higher than 94 % of the theoretical density. Scanning electron microscope (SEM) observations show that the BZTN grain sizes increase with increasing amounts of MgO. No secondary phases in the MgO doped BZTN ceramics were observed using X-ray diffraction (XRD) analysis. A high dielectric constant of 220, a low dielectric loss of 0.02 % and a stable temperature coefficient of capacitance (ΔC/C ∼ ±12 % in the temperature range from −55 to 125 °C) were obtained for 0.5 mol.% MgO-doped BZTN ceramics sintered at 900 °C for 2 h.
This study used flexible polymer materials in large-area roll printing to control the curvature feature size of the microstructure mold array of polydimethylsiloxane (PDMS) through system-developed ...equipment and gas-assisted molding processing. It designed and developed special roll printing equipment for curvature-adjustable flexible polymer mold for a series of tests regarding material mechanical properties. Mold, wear characteristics, and mechanical property parameters were obtained for experimental simulation, where the optimal parameters of microstructure mold forming with gas-assisted control were simulated. The simulation results were consistent with those in actual roll printing. The preliminary optical testing and applications were carried out, and verified that the innovative continuous roll printing process can obtain good large-area array forming structures.
Objective:
Sparse and conflicting evidence exists regarding mortality risk from pediatric acute respiratory distress syndrome (ARDS). We aimed to determine the pooled mortality in pediatric ARDS and ...to describe its trend over time.
Data Sources and Study Selection:
MEDLINE, EMBASE, and Web of Science were searched from 1960 to August 2015. Keywords or medical subject headings (MESH) terms used included “respiratory distress syndrome, adult,” “acute lung injury,” “acute respiratory insufficiency,” “acute hypoxemic respiratory failure,” “pediatrics,” and “child.” Study inclusion criteria were (1) pediatric patients aged 0 days to 18 years, (2) sufficient baseline data described in the pediatric ARDS group, and (3) mortality data. Randomized controlled trials (RCTs) and prospective observational studies were eligible.
Data Extraction and Synthesis:
Data on study characteristics, patient demographics, measures of oxygenation, and mortality were extracted using a standard data extraction form. Independent authors conducted the search, applied the selection criteria, and extracted the data. Methodological quality of studies was assessed. Meta-analysis using a random-effects model was performed to obtain pooled estimates of mortality. Meta-regression was performed to analyze variables contributing to change in mortality over time. Eight RCTs and 21 observational studies (n = 2274 patients) were included. Pooled mortality rate was 24% (95% confidence interval CI: 19-31). There was a decrease in mortality rates over 3 epochs (≤2000, 2001-2009, and ≥2010: 40% 95% CI: 24-59, 35% 95% CI: 21-51, and 18% 95% CI: 12-26, respectively, P < .001). Observational studies reported a higher mortality rate than RCTs (27% 95% CI: 24-29 versus 16% 95% CI: 12-20, P < .001). Earlier year of publication was an independent factor associated with mortality.
Conclusion:
Overall mortality rate in pediatric ARDS is approximately 24%. Studies conducted and published later were associated with better survival.
There is a scarcity of data regarding coronavirus disease 2019 (COVID-19) infection in children from southeast and south Asia. This study aims to identify risk factors for severe COVID-19 disease ...among children in the region. This is an observational study of children with COVID-19 infection in hospitals contributing data to the Pediatric Acute and Critical Care COVID-19 Registry of Asia. Laboratory-confirmed COVID-19 cases were included in this registry. The primary outcome was severity of COVID-19 infection as defined by the World Health Organization (WHO) (mild, moderate, severe, or critical). Epidemiology, clinical and laboratory features, and outcomes of children with COVID-19 are described. Univariate and multivariable logistic regression models were used to identify risk factors for severe/critical disease. A total of 260 COVID-19 cases from eight hospitals across seven countries (China, Japan, Singapore, Malaysia, Indonesia, India, and Pakistan) were included. The common clinical manifestations were similar across countries: fever (64%), cough (39%), and coryza (23%). Approximately 40% of children were asymptomatic, and overall mortality was 2.3%, with all deaths reported from India and Pakistan. Using the multivariable model, the infant age group, presence of comorbidities, and cough on presentation were associated with severe/critical COVID-19. This epidemiological study of pediatric COVID-19 infection demonstrated similar clinical presentations of COVID-19 in children across Asia. Risk factors for severe disease in children were age younger than 12 months, presence of comorbidities, and cough at presentation. Further studies are needed to determine whether differences in mortality are the result of genetic factors, cultural practices, or environmental exposures.
In 2015, the Pediatric Acute Lung Injury Consensus Conference (PALICC) provided the first pediatric-specific definitions for acute respiratory distress syndrome (pediatric acute respiratory distress ...syndrome PARDS). These definitions have since been operationalized in cohort and interventional PARDS studies. As substantial data have accrued since 2015, we have an opportunity to assess the construct validity and utility of the initial PALICC definitions. Therefore, the Second PALICC (PALICC-2) brought together multiple PARDS experts and aimed to identify and summarize relevant evidence related to the definition and epidemiology of PARDS and create modifications to the definition of PARDS.
MEDLINE (Ovid), Embase (Elsevier), and CINAHL Complete (EBSCOhost).
We included studies of subjects with PARDS, or at risk for PARDS, excluding studies pertaining primarily to adults except as specified for identifying age-specific cutoffs.
Title/abstract review, full-text review, and data extraction using a standardized data collection form.
The Grading of Recommendations Assessment, Development, and Evaluation approach was used to identify and summarize evidence and develop recommendations. A total of 97 studies were identified for full-text extraction addressing distinct aspects of the PARDS definition, including age, timing, imaging, oxygenation, modes of respiratory support, and specific coexisting conditions. Data were assessed in a Patient/Intervention/Comparator/Outcome format when possible, and formally summarized for effect size, risk, benefit, feasibility of implementation, and equity. A total of 17 consensus-based definition statements were made that update the definition of PARDS, as well as the related diagnoses of "Possible PARDS" and "At-Risk for PARDS." These statements are presented alongside a summary of the relevant epidemiology.
We present updated, data-informed consensus statements on the definition for PARDS and the related diagnoses of "Possible PARDS" and "At-Risk for PARDS."
The use of point of care ultrasound (POCUS) at the bedside has increased dramatically within emergency medicine and in critical care. Applications of POCUS have spread to include diaphragmatic ...assessments in both adults and children. Diaphragm POCUS can be used to assess for diaphragm dysfunction (DD) and atrophy or to guide ventilator titration and weaning. Quantitative, semi‐quantitative and qualitative measurements of diaphragm thickness, diaphragm excursion, and diaphragm thickening fraction provide objective data related to DD and atrophy. The potential for quick, noninvasive, and repeatable bedside diaphragm assessments has led to a growing amount of literature on diaphragm POCUS. To date, there are no reviews of the current state of diaphragm POCUS in pediatric critical care. The aims of this narrative review are to summarize the current literature regarding techniques, reference values, applications, and future innovations of diaphragm POCUS in critically ill children. A summary of current practice and future directions will be discussed.
High-frequency oscillatory ventilation (HFOV) is a type of invasive mechanical ventilation that employs supra-physiologic respiratory rates and low tidal volumes (V
) that approximate the anatomic ...deadspace. During HFOV, mean airway pressure is set and gas is then displaced towards and away from the patient through a piston. Carbon dioxide (CO
) is cleared based on the power (amplitude) setting and frequency, with lower frequencies resulting in higher V
and CO
clearance. Airway pressure amplitude is significantly attenuated throughout the respiratory system and mechanical strain and stress on the alveoli are theoretically minimized. HFOV has been purported as a form of lung protective ventilation that minimizes volutrauma, atelectrauma, and biotrauma. Following two large randomized controlled trials showing no benefit and harm, respectively, HFOV has largely been abandoned in adults with ARDS. A multi-center clinical trial in children is ongoing. This article aims to review the physiologic rationale for the use of HFOV in patients with acute respiratory failure, summarize relevant bench and animal models, and discuss the potential use of HFOV as a primary and rescue mode in adults and children with severe respiratory failure.
We aimed to assess the prognostic importance of perinephric fat features in images of patients with non-metastatic renal cell carcinoma (RCC) undergoing surgery.
We enrolled RCC patients who ...underwent surgical treatment between 2011 and 2019. Two characteristics, including perinephric fat thickness and perinephric fat stranding, were evaluated using preoperative computed tomography or magnetic resonance images. The association between perinephric fat characteristics and disease progression was examined by Kaplan-Meier survival analysis and Cox regression model.
In a multivariate Cox proportional hazards model adjusting for tumor stage, intratumoral necrosis, and neutrophil-to-lymphocyte ratio, we found that patients in the thin perinephric fat group (<1 cm) had a poorer progression-free survival (PFS) compared to the thick perinephric fat group (≥1 cm) (HR 2.8; 95% CI 1.175–6.674, p = 0.02). Additionally, the fat stranding group had a poorer PFS than the non-stranding group (HR 3.852; 95% CI 1.082–13.704, p = 0.037). The non-stranding with thick perinephric fat group exhibits the highest cumulative PFS while the stranding with thin perinephric fat group has the lowest cumulative PFS. In receiver operating characteristic curve analysis, combing these two perinephric fat characteristics with tumor stage can achieve a better discriminatory power than tumor stage alone.
Our study indicates that the evaluation of image-based perinephric fat features is a simple, straightforward, reproducible tool for predicting RCC prognosis and may assist in preoperative risk stratification.
The Pediatric Acute Lung Injury Consensus Conference developed a pediatric specific definition for acute respiratory distress syndrome (PARDS). In this definition, severity of lung disease is ...stratified into mild, moderate, and severe groups. We aim to describe the epidemiology of patients with PARDS across Asia and evaluate whether the Pediatric Acute Lung Injury Consensus Conference risk stratification accurately predicts outcome in PARDS.
A multicenter, retrospective, descriptive cohort study.
Ten multidisciplinary PICUs in Asia.
All mechanically ventilated children meeting the Pediatric Acute Lung Injury Consensus Conference criteria for PARDS between 2009 and 2015.
None.
Data on epidemiology, ventilation, adjunct therapies, and clinical outcomes were collected. Patients were followed for 100 days post diagnosis of PARDS. A total of 373 patients were included. There were 89 (23.9%), 149 (39.9%), and 135 (36.2%) patients with mild, moderate, and severe PARDS, respectively. The most common risk factor for PARDS was pneumonia/lower respiratory tract infection (309 82.8%). Higher category of severity of PARDS was associated with lower ventilator-free days (22 17-25, 16 0-23, 6 0-19; p < 0.001 for mild, moderate, and severe, respectively) and PICU free days (19 11-24, 15 0-22, 5 0-20; p < 0.001 for mild, moderate, and severe, respectively). Overall PICU mortality for PARDS was 113 of 373 (30.3%), and 100-day mortality was 126 of 317 (39.7%). After adjusting for site, presence of comorbidities and severity of illness in the multivariate Cox proportional hazard regression model, patients with moderate (hazard ratio, 1.88 95% CI, 1.03-3.45; p = 0.039) and severe PARDS (hazard ratio, 3.18 95% CI, 1.68, 6.02; p < 0.001) had higher risk of mortality compared with those with mild PARDS.
Mortality from PARDS is high in Asia. The Pediatric Acute Lung Injury Consensus Conference definition of PARDS is a useful tool for risk stratification.
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