High-flow nasal cannula in children with asthma exacerbation: A review of current evidence

Institutional Variability in Respiratory Support Use for Pediatric Critical Asthma: A Multicenter Retrospective Study

Rationale: Over 20,000 children are hospitalized in the United States for asthma every year. Although initial treatment guidelines are well established, there is a lack of high-quality evidence regarding the optimal respiratory support devices for these patients.Objectives: The objective of this study was to evaluate institutional and temporal variability in the use of respiratory support modalities for pediatric critical asthma.Methods: We conducted a retrospective cohort study using data from the Virtual Pediatrics Systems database. Our study population included children older than 2 years old admitted to a VPS contributing pediatric intensive care unit from January 2012 to December 2021 with a primary diagnosis of asthma or status asthmaticus. We evaluated the percentage of encounters using a high-flow nasal cannula (HFNC), continuous positive airway pressure (CPAP), noninvasive bilevel positive pressure ventilation (NIV), and invasive mechanical ventilation (IMV) for all institutions, then divided institutions into quintiles based on the volume of patients. We created logistic regression models to determine the influence of institutional volume and year of admission on respiratory support modality use. We also conducted time-series analyses using Kendall's tau.Results: Our population included 77,115 patient encounters from 163 separate institutions. Institutional use of respiratory modalities had significant variation in HFNC (28.3%, interquartile range [IQR], 11.0-49.0%; P < 0.01), CPAP (1.4%; IQR, 0.3-4.3%; P < 0.01), NIV (8.6%; IQR, 3.5-16.1%; P < 0.01), and IMV (5.1%; IQR, 3.1-8.2%; P < 0.01). Increased institutional patient volume was associated with significantly increased use of NIV (odds ratio [OR], 1.33; 1.29-1.36; P < 0.01) and CPAP (OR, 1.20; 1.15-1.25; P < 0.01), and significantly decreased use of HFNC (OR, 0.80; 0.79-0.81; P < 0.01) and IMV (OR, 0.82; 0.79-0.86; P < 0.01). Time was also associated with a significant increase in the use of HFNC (11.0-52.3%; P < 0.01), CPAP (1.6-5.4%; P < 0.01), and NIV (3.7-21.2%; P < 0.01), whereas there was no significant change in IMV use (6.1-4.0%; P = 0.11).Conclusions: Higher-volume centers are using noninvasive positive pressure ventilation more frequently for pediatric critical asthma and lower frequencies of HFNC and IMV. Treatment with HFNC, CPAP, and NIV for this population is increasing in the last decade.

High-Flow Humidified Oxygen as an Early Intervention in Children With Acute Severe Asthma: Protocol for a Feasibility Randomized Controlled Trial

BACKGROUND

Acute severe asthma (ASA) is a leading cause of hospital attendance in children. Standard first-line therapy consists of high-dose inhaled bronchodilators plus oral corticosteroids. Treatment for children who fail to respond to first-line therapy is problematic: the use of intravenous agents is inconsistent, and side effects are frequent. High-flow humidified oxygen (HiFlo) is widely used in respiratory conditions and is increasingly being used in ASA, but with little evidence for its effectiveness. A well-designed, adequately powered randomized controlled trial (RCT) of HiFlo therapy in ASA is urgently needed, and feasibility data are required to plan such an RCT. In this study, we describe the protocol for a feasibility study designed to fill this knowledge gap.

OBJECTIVE

This study aims to establish whether a full RCT of early HiFlo therapy in children with ASA can be conducted successfully and safely, to establish whether recruitment using deferred consent is practicable, and to define appropriate outcome measures and sample sizes for a definitive RCT. The underlying hypothesis is that early HiFlo therapy in ASA will reduce the need for more invasive treatments, allow faster recovery and discharge from hospital, and in both these ways reduce distress to children and their families.

METHODS

We conducted a feasibility RCT with deferred consent to assess the use of early HiFlo therapy in children aged 2 to 11 years with acute severe wheeze not responding to burst therapy (ie, high-dose inhaled salbutamol with or without ipratropium). Children with a Preschool Respiratory Assessment Measure score ≥5 after burst therapy were randomized to commence HiFlo therapy or follow standard care. The candidate primary outcomes assessed were treatment failure requiring escalation and time to meet hospital discharge criteria. Patient and parent experiences were also assessed using questionnaires and telephone interviews.

RESULTS

The trial was opened to recruitment in February 2020 but was paused for 15 months owing to the COVID-19 pandemic. The trial was reopened at the lead site in July 2021 and opened at the other 3 sites from August to December 2022. Recruitment was completed in June 2023.

CONCLUSIONS

This feasibility RCT of early HiFlo therapy in children with ASA recruited to the target despite major disturbances owing to the COVID-19 pandemic. The data are currently being analyzed and will be published separately.

TRIAL REGISTRATION

International Standard Randomised Controlled Trial Number Registry ISRCTN78297040; https://www.isrctn.com/ISRCTN78297040.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/54081.

Clinical review of high-flow nasal oxygen therapy in human and veterinary patients

Oxygen therapy is the first-line treatment for hypoxemic acute respiratory failure. In veterinary medicine this has traditionally been provided via mask, low-flow nasal oxygen cannulas, oxygen cages and invasive positive pressure ventilation. Traditional non-invasive modalities are limited by the maximum flow rate and fraction of inspired oxygen (FiO₂) that can be delivered, variability in oxygen delivery and patient compliance. The invasive techniques are able to provide higher FiO₂ in a more predictable manner but are limited by sedation/anesthesia requirements, potential complications and cost. High-flow nasal oxygen therapy (HFNOT) represents an alternative to conventional oxygen therapy. This modality delivers heated and humidified medical gas at adjustable flow rates, up to 60 L/min, and FiO₂, up to 100%, via nasal cannulas. It has been proposed that HFNOT improves pulmonary mechanics and reduces respiratory fatigue via reduction of anatomical dead space, provision of low-level positive end-expiratory pressure (PEEP), provision of constant FiO₂ at rates corresponding to patient requirements and through improved patient tolerance. Investigations into the use of HFNOT in veterinary patients have increased in frequency since its clinical use was first reported in dogs with acute respiratory failure in 2016. Current indications in dogs include acute respiratory failure associated with pulmonary parenchymal disease, upper airway obstruction and carbon monoxide intoxication. The use of HFNOT has also been advocated in certain conditions in cats and foals. HFNOT is also being used with increasing frequency in the treatment of a widening range of conditions in humans. Although there remains conflict regarding its use and efficacy in some patient groups, overall these reports indicate that HFNOT decreases breathing frequency and work of breathing and reduces the need for escalation of respiratory support. In addition, they provide insight into potential future veterinary applications. Complications of HFNOT have been rarely reported in humans and animals. These are usually self-limiting and typically result in lower morbidity and mortality than those associated with invasive ventilation techniques.

Noninvasive positive-pressure ventilation for children with acute asthma: a meta-analysis of randomized controlled trials

Background

Noninvasive positive-pressure ventilation (NPPV) can be effective in children with acute asthma. However, clinical evidence remains limited. The objective of the meta-analysis was to systematically assess NPPV's effectiveness and safety in treating children with acute asthma.

Methods

Relevant randomized controlled trials were obtained from electronic resources, including PubMed, Embase, Cochrane's Library, Wanfang, and CNKI databases. The influence of potential heterogeneity was taken into account before using a random-effect model to pool the results.

Results

A total of 10 RCTs involving 558 children with acute asthma were included in the meta-analysis. Compared to conventional treatment alone, additional use of NPPV significantly improved early blood gas parameters such as the oxygen saturation (mean difference [MD]: 4.28%, 95% confidence interval [CI]: 1.51 to 7.04, p = 0.002; I² = 80%), partial pressure of oxygen (MD: 10.61 mmHg, 95% CI: 6.06 to 15.16, p < 0.001; I² = 89%), and partial pressure of carbon dioxide (MD: -6.29 mmHg, 95% CI: -9.81 to -2.77, p < 0.001; I² = 85%) in the arterial blood. Moreover, NPPV was also associated with early reduced respiratory rate (MD: -12.90, 95% CI: -22.21 to -3.60, p = 0.007; I²= 71%), improved symptom score (SMD: -1.85, 95% CI: -3.65 to -0.07, p = 0.04; I² = 92%), and shortened hospital stay (MD: -1.82 days, 95% CI: -2.32 to -1.31, p < 0.001; I²= 0%). No severe adverse events related to NPPV were reported.

Conclusions

NPPV in children with acute asthma is associated with improved gas exchange, decreased respiratory rates, a lower symptom score, and a shorter hospital stay. These results suggest that NPPV may be as effective and safe as conventional treatment for pediatric patients with acute asthma.

Factors associated with failure of using high flow nasal cannula in children

INTRODUCTION

High flow nasal cannula (HFNC) has significantly success in treating acute respiratory distress while HFNC failure dramatically increases mortality and morbidity.

OBJECTIVE

To describe factors associated with failure of HFNC use in children.

METHODS

We performed a retrospective observational study using demographic and laboratory findings. We compared clinical and laboratory variables in both successful and failed HFNC groups. The correlations between factors and HFNC failure were constructed by binary logistic regression analysis.

RESULTS

Between August 2016 and May 2018, 250 children receiving HFNC (median age 16 months; range 1-228 months, male 50.8%) were enrolled. Pneumonia was the most common cause of respiratory distress, and the median length of stay (LOS) in hospital was 11 days. HFNC failure was found 16.4% while HFNC complication was 4.8% including epistaxis, pressure sore, and gastric distension. Based on multivariable logistic regression analysis, factors associated with HFNC failure were children with congenital heart disease comorbidity (p = 0.005), HFNC use with maximum FiO₂  > 0.6 (p = 0.021), lobar infiltration on chest X-ray (p = 0.012), the reduction of heart rate, and respiratory rate <20% after 1 h of HFNC use (p = 0.001 and p = 0.001, respectively).

CONCLUSION

HFNC is feasible to use for children with respiratory distress; however, patients with congenital heart disease, using HFNC with FiO₂  > 0.6, lobar infiltration on chest X-ray should be closely monitored. Heart rate and respiratory rate are important parameters in addition to clinical assessment for evaluating HFNC failure in children.

Management of Acute Asthma in Children

Asthma is the most common disease of childhood globally and acute asthma is the most significant risk factor for asthma-related death and chronic complications. This article will aim to synthesize the most up-to-date research and translate it into a more practical guide to managing acute asthma on a more daily basis. The use of clinical severity score is reviewed alongside the use of history and clinical findings in making objective assessments of patients presenting with acute asthma. Practical evidence-based pathways and a stepwise approach are provided for management of acute asthma in the home, outpatient, emergency, and intensive care settings. In doing so, popular myths are dispelled and practices in relation to management of acute asthma and use of asthma related medications are clarified. Having a standardized approach to management of acute asthma will bring us one step closer to reducing exacerbations and achieving the goal of having zero tolerance towards exacerbations.