The Relationship between High Flow Nasal Cannula Flow Rate and Effort of Breathing in Children

High flow, low results: The limits of high flow nasal cannula in the treatment of bronchiolitis

Bronchiolitis continues to be the most common cause of hospitalization in the first year of life. We continue to search for the remedy that will improve symptoms, shorten hospitalization and prevent worsening of disease. Although initially thought to be a promising therapy, large randomized controlled trials show us that high flow nasal cannula (HFNC) use is not that remedy. These trials show no major differences in duration of hospital stay, intensive care unit (ICU) admission rates, duration of stay in the ICU, duration of oxygen therapy, intubation rates, heart rate, respiratory rate or comfort scores. Additionally, practices regarding initiation, flow rates and weaning continue to vary from institution to institution and there are currently no agreed upon indications for its use. This reveals the need for evidence based guidelines on HFNC use in bronchiolitis.

Impact of initial high flow nasal cannula flow rates on clinical outcomes in children with bronchiolitis

PURPOSE

Our aim was to evaluate the impact of the initial high flow nasal cannula (HFNC) flow rate on clinical outcomes in children with bronchiolitis.

METHODS

This secondary analysis of retrospective data included children <2 years who required HFNC for bronchiolitis between 10/01/2018-04/20/2019, and following implementation of a revised institutional bronchiolitis pathway between 10/01/2021-04/30/2022. The new pathway recommended weight-based initiation of HFNC at 1.5-2 L/kg/min. We evaluated the effect of low (<1.0 L/kg/min), medium (1-1.5 L/kg/min) and high (>1.5 L/kg/min) HFNC flow rates on need for positive pressure ventilation (PPV), intensive care unit (ICU) transfer, HFNC treatment time, and hospital length of stay (LOS).

RESULTS

The majority of the 885 included children had low initial flow rates (low [n = 450, 50.8%], medium [n = 332, 37.5%] and high [n = 103, 11.7%]). There were no significant differences in PPV (high: 7.8% vs. medium: 9.3% vs. low: 8.2%, p = 0.8) or ICU transfers (high: 4.9% vs. medium: 6.0% vs. low: 3.8%, p = 0.3). The low flow group had a significantly longer median HFNC treatment time (High: 29 [18, 45] vs. medium: 29 [16, 50] vs. low: 39 [25, 63], p < .001) and hospital LOS (High: 41 [27, 59] vs. medium: 42 [29, 66] vs. low: 50 (39, 75), p < .001). Logistic and linear regression models did not demonstrate any associations between HFNC flow rates and PPV or hospital LOS.

CONCLUSIONS

Initial HFNC flow rates were not associated with significant changes in clinical outcomes in children in children with bronchiolitis.

The effects of flow settings during high-flow nasal cannula oxygen therapy for neonates and young children

BACKGROUND

During neonatal and paediatric high-flow nasal cannula therapy, optimising the flow setting is crucial for favourable physiological and clinical outcomes. However, considerable variability exists in clinical practice regarding initial flows and subsequent adjustments for these patients. Our review aimed to summarise the impact of various flows during high-flow nasal cannula treatment in neonates and children.

METHODS

Two investigators independently searched PubMed, Embase, Web of Science, Scopus and Cochrane for in vitro and in vivo studies published in English before 30 April 2023. Studies enrolling adults (≥18 years) or those using a single flow setting were excluded. Data extraction and risk of bias assessments were performed independently by two investigators. The study protocol was prospectively registered with PROSPERO (CRD42022345419).

RESULTS

38 406 studies were identified, with 44 included. In vitro studies explored flow settings' effects on airway pressures, humidity and carbon dioxide clearance; all were flow-dependent. Observational clinical studies consistently reported that higher flows led to increased pharyngeal pressure and potentially increased intrathoracic airway pressure (especially among neonates), improved oxygenation, and reduced respiratory rate and work of breathing up to a certain threshold. Three randomised controlled trials found no significant differences in treatment failure among different flow settings. Flow impacts exhibited significant heterogeneity among different patients.

CONCLUSION

Individualising flow settings in neonates and young children requires consideration of the patient's peak inspiratory flow, respiratory rate, heart rate, tolerance, work of breathing and lung aeration for optimal care.

ROX (Respiratory rate-OXygenation) index to predict early response to high-flow nasal cannula therapy in infants with viral bronchiolitis

INTRODUCTION

High-flow nasal cannula (HFNC) is commonly used as first step respiratory support in infants with moderate-to-severe acute viral bronchiolitis (AVB). This device, however, fails to effectively manage respiratory distress in about a third of patients, and data are limited on determinants of patient response. The respiratory rate-oxygenation (ROX) index is a relevant tool to predict the risk for HFNC failure in adult patients with lower respiratory tract infections. The primary objective of this study was to assess the relationship between ROX indexes collected before and 1 h after HFNC initiation, and HFNC failure occurring in the following 48 h in infants with AVB.

METHOD

This is an ancillary study to the multicenter randomized controlled trial TRAMONTANE 2, that included 286 infants of less than 6 months with moderate-to-severe AVB. Collection of physiological variables at baseline (H0), and 1 h after HFNC (H1), included heart rate (HR), respiratory rate (RR), fraction of inspired oxygen (FiO2 ), respiratory distress score (modified Wood's Clinical Asthma Score [mWCAS]), and pain and discomfort scale (EDIN). ROX and ROX-HR were calculated asSpO 2 FiO 2 RR $\frac{\left(\frac{{\mathrm{SpO}}_{2}}{{\mathrm{FiO}}_{2}}\right)}{\mathrm{RR}}$ and100 × ROX HR $100\times \frac{\mathrm{ROX}}{\mathrm{HR}}$ , respectively. Predefined HFNC failure criteria included increase in respiratory distress score or RR, increase in discomfort, and severe apnea episodes. The accuracies of ROX, ROX-HR indexes and clinical variable to predict HFNC failure were assessed using receiver operating curve analysis. We analyzed predictive factors of HFNC failure using multivariate logistic regressions.

RESULT

HFNC failure occurred in 111 of 286 (39%) infants, and for 56 (50% of the failure) of them within the first 6 h. The area under the curve of ROX indexes at H0 and H1 were, respectively, 0.56 (95% confidence interval [CI] 0.48-0.63, p = 0.14), 0.56 (95% CI 0.49-0.64, p = 0.09). ROX-HR performances were better but remained poorly discriminant. HFNC failure was associated with higher mWCAS score at H1 (p < 0.01) and lower decrease in EDIN scale during the first hour of HFNC delivery (p = 0.02). In the multivariate analyses, age and mWCAS score were were found to be independent factors associated with HFNC failure at H0. At H1, weight and mWCAS were associated factors.

CONCLUSION

In this study, neither ROX index, nor physiological variables usually collected in infants with AVB had early discriminatory capacity to predict HFNC failure.

When to Transfer: Predictors of Pediatric High Flow Nasal Cannula Failure at a Community Hospital

OBJECTIVES

To identify risk factors of high flow nasal cannula (HFNC) failure at a US pediatric hospital without a co-located ICU.

METHODS

Retrospective cohort study of patients aged 0 to 18 years who were started on HFNC in the emergency department or inpatient unit at a community hospital over a 16-month period. Children with chronic medical conditions were excluded. Outcome was HFNC failure, defined as HFNC need greater than floor limit, noninvasive positive pressure, or mechanical ventilation. In bivariate analysis, we compared demographic and clinical factors between those with and without failure. We included variables in a multivariable model on the basis of statistical significance. We used Poisson regression with robust error variance to calculate the adjusted relative risk (aRR) of failure for each variable.

RESULTS

Of 195 children, 51% had HFNC failure. In adjusted analysis, failure was higher in all age groups <12 months as compared with older children. For example, children aged 3 to 5 months had a higher risk of failure compared with patients 12 months or older (aRR 1.85, confidence interval [CI] 1.34-2.54). Patients with an asthma exacerbation had a higher risk of failure (aRR 1.39, CI 1.03-1.88). Patients whose respiratory rate or heart rate did not improve also had a higher risk of failure (aRR 1.73, CI 1.24-2.41; aRR 1.47, CI 1.14-1.90).

CONCLUSIONS

Patients who were younger, had asthma, and did not have improved respiratory rate or heart rate after HFNC were more likely to experience HFNC failure.

Extubation to High-Flow Nasal Cannula in Infants Following Cardiac Surgery: A Retrospective Cohort Study

High-flow nasal cannula (HFNC) therapy is commonly used in the pediatric intensive care unit (PICU) for postextubation respiratory support. This hypothesis-generating retrospective cohort study aimed to compare postextubation PICU length of stay in infants extubated to HFNC and low flow oxygen (LF) in PICU following cardiac surgery. Of 136 infants (newborn to 1 year) who were intubated and mechanically ventilated in PICU following cardiac surgery, 72 (53%) were extubated to HFNC and 64 (47%) to LF. Compared with patients extubated to LF, those extubated to HFNC had significantly longer durations of cardiopulmonary bypass (152 vs. 109 minutes; p  = 0.002), aortic cross-clamp (90 vs. 63 minutes; p  = 0.003), and invasive mechanical ventilation (3.2 vs. 1.6 days; p  < 0.001), although demographic and preoperative clinical variables were similar. No significant difference was observed in postextubation PICU length of stay between HFNC and LF groups in unadjusted analysis (3.3 vs. 2.6 days, respectively; p  = 0.19) and after controlling for potential confounding variables (F [1,125] = 0.17, p  = 0.68, R 2  = 0.16). Escalation of therapy was similar between HFNC and LF groups (8.3 vs. 14.1%; p  = 0.41). HFNC was effective as rescue therapy for six patients in the LF group requiring escalation of therapy. Need for reintubation was similar between HFNC and LF groups (8.3 vs. 4.7%; p  = 0.5). Although extubation to HFNC was associated with a trend toward longer postextubation PICU length of stay and was successfully used as rescue therapy for several infants extubated to LF, our results must be interpreted with caution given the limitations of our study.

Randomized Trial of Weight-Based Versus Fixed Limit High-Flow Nasal Cannula in Bronchiolitis

BACKGROUND

High flow nasal cannula (HFNC) is increasingly used to treat bronchiolitis. Although lower HFNC rates (≤8 L per minute) are commonly employed, higher weight-based flows more effectively alleviate dyspnea. The impact of higher flows on the need for care escalation is unclear.

METHODS

A randomized clinical trial was performed in a community hospital inpatient pediatric unit. Patients with bronchiolitis on HFNC were randomized to an existing "standard" HFNC protocol (max flow of 8 L per minute), or to a novel weight-based protocol (max flow of 2 L/kg per minute). Weaning of HFNC for the patients in the standard arm was left to provider discretion but was prescribed in the weight-based arm. The primary outcome was interhospital transfer to a PICU. The study was powered to detect a 35% difference in transfer rate.

RESULTS

51 patients were randomized to the weight-based or standard HFNC arms. The interhospital PICU transfer rate did not differ significantly between the standard (41.7%) and weight-based arms (51.9%) P = .47. Hospital length of stay was significantly shorter in the weight-based arm with protocolized weaning (45 h [interquartile range 42.1-63.3] versus 77.6 h [interquartile range 47.3-113.4]); P = .01. There were no significant adverse events in either group.

CONCLUSIONS

Weight-based provision of HFNC did not significantly impact the number of patients with bronchiolitis requiring interhospital transfer from a community hospital to a PICU, though we were underpowered for this outcome. Patients who received weight-based flow with protocolized weaning had a shorter length of stay, which may reflect a clinical impact of weight-based flow or the efficacy of the aggressive weaning pathway.

Operational Definitions Related to Pediatric Ventilator Liberation

BACKGROUND

Common, operational definitions are crucial to assess interventions and outcomes related to pediatric mechanical ventilation. These definitions can reduce unnecessary variability among research and quality improvement efforts, to ensure findings are generalizable, and can be pooled to establish best practices.

RESEARCH QUESTION

Can we establish operational definitions for key elements related to pediatric ventilator liberation using a combination of detailed literature review and consensus-based approaches?

STUDY DESIGN AND METHODS

A panel of 26 international experts in pediatric ventilator liberation, two methodologists, and two librarians conducted systematic reviews on eight topic areas related to pediatric ventilator liberation. Through a series of virtual meetings, we established draft definitions that were voted upon using an anonymous web-based process. Definitions were revised by incorporating extracted data gathered during the systematic review and discussed in another consensus meeting. A second round of voting was conducted to confirm the final definitions.

RESULTS

In eight topic areas identified by the experts, 16 preliminary definitions were established. Based on initial discussion and the first round of voting, modifications were suggested for 11 of the 16 definitions. There was significant variability in how these items were defined in the literature reviewed. The final round of voting achieved ≥ 80% agreement for all 16 definitions in the following areas: what constitutes respiratory support (invasive mechanical ventilation and noninvasive respiratory support), liberation and failed attempts to liberate from invasive mechanical ventilation, liberation from respiratory support, duration of noninvasive respiratory support, total duration of invasive mechanical ventilation, spontaneous breathing trials, extubation readiness testing, 28 ventilator-free days, and planned vs rescue use of post-extubation noninvasive respiratory support.

INTERPRETATION

We propose that these consensus-based definitions for elements of pediatric ventilator liberation, informed by evidence, be used for future quality improvement initiatives and research studies to improve generalizability and facilitate comparison.

Is implementation of a hospital pathway for high-flow nasal cannula initiation and weaning associated with reduced high-flow duration in bronchiolitis?

BACKGROUND

High-flow nasal cannula (HFNC) therapy is widely used for children with bronchiolitis, but its optimal role remains uncertain. Our institution created and later revised a clinical pathway guiding HFNC initiation and weaning.

METHODS

A retrospective review of 1690 bronchiolitis encounters was conducted. Trends in the duration of HFNC and hours spent weaning HFNC as proportions of the monthly hospital length of stay (LOS) for bronchiolitis, hospital LOS, and escalation of care were compared using interrupted time series (ITS) models across three study periods: Baseline (HFNC managed at provider discretion), Intervention 1 (pathway with initiation at 0.5 L/kg/min and escalation up to 2 L/kg/min), and Intervention 2 (revised pathway, initiation at the maximum rate of 2 L/kg/min). Both pathway iterations provided titration and weaning guidance. Maximum respiratory scores were used to adjust for case severity.

RESULTS

After adjustment for severity and time, both HFNC duration and HFNC weaning time (as a proportion of monthly LOS) decreased at the start of Intervention 1, but subsequently increased. During Intervention 2, both these measures trended downward, returning to baseline. Total LOS did not change in the baseline or intervention periods. Escalation of care did not differ from baseline to the end of Intervention 2.

CONCLUSION

Initiating HFNC at higher flow rates with weaning guidance for children hospitalized with bronchiolitis was associated with a reduction in HFNC duration without differences in LOS or escalation of care. These findings suggest that standardization through clinical pathways can limit HFNC duration in bronchiolitis.

Effect of flow rate on the end-expiratory lung volume in infants with bronchiolitis using high-flow nasal cannula evaluated through electrical impedance tomography

OBJECTIVES

To evaluate the effects of four flow rates on the functional residual capacity (FRC) and pulmonary ventilation distribution while using a high-flow nasal cannula (HFNC).

WORKING HYPOTHESIS

Our hypothesis is that flow rates below 1.5 L·kg^-1 ·min^-1 lead to FRC loss and respiratory distress.

STUDY DESIGN

A single-center, prospective clinical study.

PATIENT SELECTION

Infants diagnosed with acute viral bronchiolitis were given HFNC.

METHODOLOGY

Through a prospective clinical study, the effects of four different flow rates, 2.0, 1.5, 1.0, and 0.5 L·kg^-1 ·min^-1 , on FRC and the pulmonary ventilation pattern were evaluated using electrical impedance tomography. The impedance variation (delta Z), end-expiratory lung volume (EELZ), respiratory rate, heart rate, respiratory distress score, and saturation/fraction of inspired oxygen ratio (SpO₂ /F_I O₂ ), were also evaluated at each flow rate.

RESULTS

Among the 11 infants included, There was a decrease in respiratory distress score at a flow rate of 1.5 L·kg^-1 ·min^-1 (*p = 0.021), and at a flow rate of 2.0 L·kg^-1 ·min^-1 (**p = 0.003) compared to 0.5 L·kg^-1 ·min^-1 . There was also a small but significant increase in SpO₂ /FiO₂ at flow rates of 1.5 (*p = 0.023), and 2.0 L·kg^-1 ·min^-1 (**p = 0.008) compared to 0.5 L·kg^-1 ·min^-1 . There were no other significant changes in the clinical parameters. In the global EELZ measurements, there was a significant increase under a flow rate of 2.0 L·kg^-1 ·min^-1 as compared to 0.5 L·kg^-1 ·min^-1 (p = 0.03). In delta Z values, there were no significant variations between the different flow rates.

CONCLUSION

The ∆EELZ increases at the highest flow rates were accompanied by decreased distress scores and improved oxygenation.

Randomized Trial to Compare Nasoduodenal Tube and Nasogastric Tube Feeding in Infants with Bronchiolitis on High-Flow Nasal Cannula

Objectives In this article, we aimed to determine if there is a difference in length of respiratory support between nasoduodenal (NDT) and nasogastric tube (NGT) feedings in patients with bronchiolitis on high-flow nasal cannula (HFNC).

Methods A single-center nonblinded parallel randomized control trial at a tertiary care hospital was designed. Pediatric patients ≤ 12 months old with bronchiolitis, on HFNC, requiring nutrition via a feeding tube were eligible. Patients were randomized to NGT or NDT and stratified into low- and high-risk groups. Length of respiratory support was the primary outcome. Secondary outcomes included length of stay, number of emesis events, maximum level of respiratory support, number of X-rays to confirm tube placement, number of attempts to place the tube by staff, adverse events during placement, instances of pediatric intensive care unit admission, and emergency room visits and hospital readmissions within 7 and 30 days after discharge.

Results Forty patients were randomized, 20 in each arm. There were no significant differences in baseline characteristics. We found no significant difference in length of respiratory support between the two groups (NGT 0.84 incidence rate ratio [0.58, 1.2], p = 0.34). None of the secondary outcomes showed significant differences. Each arm reported one adverse event: nasal trauma in the NGT group and pneumothorax in the NDT group.

Conclusion For infants with bronchiolitis on HFNC that need enteric tube feedings, we find no difference in duration of respiratory support or other clinically relevant outcomes for those with NGT or NDT. These results should be interpreted in the context of a limited sample size and an indirect primary outcome of length of respiratory support that may be influenced by other factors besides aspiration events.

Mechanical Ventilation and Respiratory Support in the Pediatric Intensive Care Unit

Children admitted to the pediatric intensive care unit often require respiratory support for the treatment of respiratory distress and failure. Respiratory support comprises both noninvasive modalities (ie, heated humidified high-flow nasal cannula, continuous positive airway pressure, bilevel positive airway pressure, negative pressure ventilation) and invasive mechanical ventilation. In this article, we review the various essential elements and considerations involved in the planning and application of respiratory support in the treatment of the critically ill children.

High Flow Nasal Cannula in the Pediatric Intensive Care Unit

INTRODUCTION

The use of high flow nasal cannula (HFNC) has become widely used in pediatric intensive care units (PICUs) throughout the world. The rapid adoption has outpaced the number of studies evaluating the safety and efficacy in a variety of pediatric diseases/conditions.

AREAS COVERED

This scoping review begins with the definition and mechanisms of action of HFNC and then follows with a review of the literature focused on studies performed on critically ill children cared for in the PICU. The Pubmed database was searched with a pediatric filter from the time period 2000 to 2021.

EXPERT OPINION

The rapid adoption of HFNC in PICUs has largely been driven by changes in institutional practices and small observational studies. There is a lack of adequately powered studies evaluating patient-centered outcomes, such as intubation rates, mortality, PICU and hospital length of stay. Given the wide variability in flow rates and clinical indications, more research is needed to better define effective flow rates for different disease states as well as markers of treatment success and failure. One particular entity that is poorly studied is the use of HFNC in those at risk for developing pediatric acute respiratory distress syndrome (PARDS).

Impact of initial flow rate of high-flow nasal cannula on clinical outcomes in infants with bronchiolitis

AIM

Bronchiolitis is a common condition in the paediatric population. Severe cases often receive respiratory support with high-flow nasal cannula (HFNC). Significant variation in the application of HFNC exists throughout Australia and internationally. This study aimed to determine if the flow rate used initially and when ceasing HFNC at the end of the illness alters clinical outcomes.

METHODS

A retrospective analysis was conducted of 251 children less than 12 months of age when admitted to the Women's and Children's Hospital Adelaide with bronchiolitis requiring HFNC therapy between the period of April 2016 to April 2019. The primary outcome was to determine if commencing HFNC therapy at different rates (1 L/kg/min, 1.5 L/kg/min and 2 L/kg/min) affected length of stay or treatment failure (escalation in physiological parameters or respiratory support).

RESULTS

Treatment failure occurred in 33%, 13% and 26% of those starting at 1 L/kg/min, 1.5 L/kg/min and 2 L/kg/min, respectively. Commencing HFNC therapy at 1 L/kg/min increased length of stay by an average of 30 h (P < 0.001) and the likelihood of treatment failure (P < 0.002) compared with starting at 1.5 L/kg/min. There was no statistical difference in outcomes between starting at 1.5 L/kg/min and 2 L/kg/min. There was no significant difference in the length of stay from the starting of weaning HFNC to time of discharge.

CONCLUSIONS

The commencing flow rates of initial HFNC therapy impact individual patient's outcomes, including length of stay and rates of treatment failure. Clinicians should consider commencing HFNC at 1.5 L/kg/min or 2 L/kg/min in infants that have failed low-flow oxygen therapy.

A New Trick for an Old Dog: L-Epinephrine Delivered Continuously in the Vapor Phase

Inhaled L-epinephrine is a known treatment of severe croup and postextubation upper airway obstruction. L-epinephrine can be delivered continuously in the vapor phase, but the indications, safety, and efficacy of this novel practice have yet to be evaluated. Theoretical risks are tachycardia, hypertension, and dysrhythmias. The study objective was to describe patient characteristics and vital sign changes related to continuous vaporized L-epinephrine use in critically ill children with the hypothesis that it can be practically and safely administered to children with subglottic edema and lower airway obstruction.

Clinical practices related to high-flow nasal cannulas in pediatric critical care in Brazil compared to other countries: a Brazilian survey

Objetivo

Descrever as práticas clínicas atuais relacionadas à utilização de cânula nasal de alto fluxo por intensivistas pediátricos brasileiros e compará-las com as de outros países.

Métodos

Para o estudo principal, foi administrado um questionário a intensivistas pediátricos em países das Américas do Norte e do Sul, Ásia, Europa e Austrália/Nova Zelândia. Comparou-se a coorte brasileira com coortes dos Estados Unidos, Canadá, Reino Unido e Índia.

Resultados

Responderam ao questionário 501 médicos, dos quais 127 eram do Brasil. Apenas 63,8% dos participantes brasileiros tinham disponibilidade de cânula nasal de alto fluxo, em contraste com 100% dos participantes no Reino Unido, no Canadá e nos Estados Unidos. Coube ao médico responsável a decisão de iniciar a utilização de uma cânula nasal de alto fluxo segundo responderam 61,2% dos brasileiros, 95,5% dos localizados no Reino Unido, 96,6% dos participantes dos Estados Unidos, 96,8% dos médicos canadenses e 84,7% dos participantes da Índia; 62% dos participantes do Brasil, 96,3% do Reino Unido, 96,6% dos Estados Unidos, 96,8% do Canadá e 84,7% da Índia relataram que o médico responsável era quem definia o desmame ou modificava as regulagens da cânula nasal de alto fluxo. Quando ocorreu falha da cânula nasal de alto fluxo por desconforto respiratório ou insuficiência respiratória, 82% dos participantes do Brasil considerariam uma tentativa com ventilação não invasiva antes da intubação endotraqueal, em comparação com 93% do Reino Unido, 88% dos Estados Unidos, 91,5% do Canadá e 76,8% da Índia. Mais intensivistas brasileiros (6,5%) do que do Reino Unido, Estados Unidos e Índia (1,6% para todos) afirmaram utilizar sedativos com frequência concomitantemente à cânula nasal de alto fluxo.

Conclusão

A disponibilidade de cânulas nasais de alto fluxo no Brasil ainda não é difundida. Há algumas divergências nas práticas clínicas entre intensivistas brasileiros e seus colegas estrangeiros, principalmente nos processos e nas tomadas de decisão relacionados a iniciar e desmamar o tratamento com cânula nasal de alto fluxo.

Implementation of a Weight-Based High-Flow Nasal Cannula Protocol for Children With Bronchiolitis

OBJECTIVES

To determine if the implementation of a weight-based high-flow nasal cannula (HFNC) protocol for infants with bronchiolitis was associated with improved outcomes, including decreased ICU use.

METHODS

We implemented a weight-based HFNC protocol across a tertiary care children's hospital and 2 community hospitals that admit pediatric patients on HFNC. We included all patients who were <2 years old and had a discharge diagnosis of bronchiolitis or viral pneumonia during the preimplementation (November 2013 to April 2018) and postimplementation (November 2018 to April 2020) respiratory seasons. Data were analyzed by using an interrupted time series approach. The primary outcome measure was the proportion of patients treated in the ICU. Patients with a complex chronic condition were excluded.

RESULTS

Implementation of the weight-based HFNC protocol was associated with an immediate absolute decrease in ICU use of 4.0%. We also observed a 6.2% per year decrease in the slope of ICU admissions pre- versus postintervention. This was associated with an immediate reduction in median cost per bronchiolitis encounter of $661, a 2.3% immediate absolute reduction in the proportion of patients who received noninvasive ventilation, and a 3.4% immediate absolute reduction in the proportion of patients who received HFNC.

CONCLUSIONS

A multicenter, weight-based HFNC protocol was associated with decreased ICU use and noninvasive ventilation use. In hospitals where HFNC is used in non-ICU units, weight-based approaches may lead to improved resource use.

High-flow nasal cannula failure: can clinical outcomes determine early interruption?

OBJECTIVE

To evaluate the evolution of clinical outcomes in children with bronchiolitis who used a high-flow nasal cannula, and to determine after long of non-clinical improvement the therapy should be discontinued, and treatment should be escalated to other forms of ventilatory support.

METHODS

An observational retrospective study of infants with bronchiolitis who used a high-flow nasal cannula. Patients were divided into two study groups according to success or failure of high-flow nasal cannula therapy, namely the Success Group and the Failure Group. The main demographics and clinical variables were assessed 30 minutes and 6 hours after initiating therapy until removal of the high-flow nasal cannula.

RESULTS

A total of 83 children were studied and 18 children (21.7%) failed therapy. Among subjects with successful therapy, a significant decrease in respiratory rate (p<0.001), and a significant increase in peripheral oxygen saturation (p<0.001) were observed within 30 minutes. The Success Group was significantly different from the Failure Group after 6 hours, for both respiratory rate (p<0.01) and peripheral oxygen saturation (p<0.01).

CONCLUSION

The absence of clinical sign improvement within 30 minutes and for up to a maximum of 6 hours can be considered as failure of the high-flow nasal cannula therapy. If this time elapses with no improvements, escalating to another type of ventilatory support should be considered.

A pediatric high-flow nasal cannula protocol standardizes initial flow and expedites weaning

OBJECTIVE

Respiratory illnesses compose the most common diagnoses of patients admitted to pediatric intensive care units. In pediatrics, high-flow nasal cannula (HFNC) therapy is an intermediate level of respiratory support with variability in practice. We conducted a pre-post intervention study of patients placed on HFNC therapy before and after the implementation of an HFNC protocol.

METHODS

This was a quality improvement/pre-post intervention study of pediatric patients who received HFNC therapy in our teaching, tertiary care children's hospital between January 2015 and April 2019. Patients were evaluated before and after the implementation of a protocol that promoted initiation of higher flow and rapid weaning. Our primary outcomes were initial flow and rate of weaning pre- and post-protocol; our secondary outcomes were HFNC failure rate (defined as escalation to noninvasive ventilation or mechanical ventilation) and length of hospital stay. Propensity matching was used to account for differences in age and weight pre- and post-protocol.

RESULTS

In total, 584 patients were included, 292 pre-protocol, and 292 post-protocol. The median age was 20 months, and the indication for HFNC therapy was bronchiolitis in 29% of patients. Post-protocol patients compared to pre-protocol patients had significantly a higher initial flow (median 14.5 L/min vs. 10 L/min, p < .001) and a higher weaning rate of flow (median 4.1 L/min/h vs. 2.4 L/min/h, p < .001). Post-protocol patients also had a lower HFNC failure rate (10% vs. 17%, p = .015) and a shorter length of stay (5.97 days vs. 6.80 days, p = .006).

CONCLUSION

Among pediatric patients, the implementation of an HFNC protocol increases initial flow, allows for more rapid weaning, and may decrease the incidence of escalation to noninvasive ventilation or mechanical ventilation.

Assessment of Peak Inspiratory Flow in Young Infants with Acute Viral Bronchiolitis: Physiological Basis for Initial Flow Setting in Patients Supported with High-Flow Nasal Cannula

OBJECTIVE

To assess the inspiratory demand in young infants with acute viral bronchiolitis to provide a physiological basis for initial flow setting for patients supported with high flow nasal cannula.

STUDY DESIGN

Prospective study in 44 infants up to 6 months old with acute viral bronchiolitis, admitted to a pediatric intensive care unit from November 2017 to March 2019. Airflow measurements were performed using spirometry. The primary endpoint was the inspiratory demand as measured by peak tidal inspiratory flow (PTIF). The secondary endpoints were the relationships determined between PTIF, patient weight, and disease severity.

RESULTS

Median (Q₂₅-Q₇₅) age and weight of the patients were 37 (20-67) days and 4.3 (3.5-5.0) kg, respectively. Mean PTIF was 7.45 (95% CI 6.51-8.39, min-max: 2.40-16.00) L/minute. PTIF indexed to weight was 1.68 (95% CI 1.51-1.85, min-max: 0.67-3.00) L/kg/minute. PTIF was <2.5 L/kg/minute in 89% (95% CI 75-96) of infants. PTIF was correlated with weight (ρ= 0 .55, P < .001) but not with markers of disease severity, including modified Woods clinical asthma score, Silverman-Andersen score, respiratory rate, fraction of inspired oxygen, and PCO₂.

CONCLUSIONS

High flow nasal cannula therapy is used commonly to support infants with acute viral bronchiolitis. The efficiency of the device is optimal if the flow setting matches the patient's inspiratory demand. According to our results, a flow rate of <2.5 L/kg/minute would be appropriate in most situations.

Quality Initiative to Reduce High-Flow Nasal Cannula Duration and Length of Stay in Bronchiolitis

OBJECTIVES

High-flow nasal cannula (HFNC) use in bronchiolitis may prolong length of stay (LOS) if weaned more slowly than medically indicated. We aimed to reduce HFNC length of treatment (LOT) and inpatient LOS by 12 hours in 0- to 18-month-old patients with bronchiolitis on the pediatric hospital medicine service.

METHODS

After identifying key drivers of slow weaning, we recruited a multidisciplinary "Wean Team" to provide education and influence provider weaning practices. We then implemented a respiratory therapist-driven weaning protocol with supportive sociotechnical interventions (huddles, standardized orders, simplification of protocol) to reduce LOT and LOS and promote sustainability.

RESULTS

In total, 283 patients were included: 105 during the baseline period and 178 during the intervention period. LOT and LOS control charts revealed special cause variation at the start of the intervention period; mean LOT decreased from 48.2 to 31.2 hours and mean LOS decreased from 84.3 to 60.9 hours. LOT and LOS were less variable in the intervention period compared with the baseline period. There was no increase in PICU transfers or 72-hour return or readmission rates.

CONCLUSIONS

We reduced HFNC LOT by 17 hours and LOS by 23 hours for patients with bronchiolitis via multidisciplinary collaboration, education, and a respiratory therapist-driven weaning protocol with supportive interventions. Future steps will focus on more judicious application of HFNC in bronchiolitis.

Diagnosis, grading and management of toxicities from immunotherapies in children, adolescents and young adults with cancer

Cancer immunotherapies are associated with remarkable therapeutic response rates but also with unique and severe toxicities, which potentially result in rapid deterioration in health. The number of clinical applications for novel immune effector-cell therapies, including chimeric antigen receptor (CAR)-expressing cells, and other immunotherapies, such as immune-checkpoint inhibitors, is increasing. In this Consensus Statement, members of the Pediatric Acute Lung Injury and Sepsis Investigators (PALISI) Network Hematopoietic Cell Transplantation-Cancer Immunotherapy (HCT-CI) Subgroup, Paediatric Diseases Working Party (PDWP) of the European Society of Blood and Marrow Transplantation (EBMT), Supportive Care Committee of the Pediatric Transplantation and Cellular Therapy Consortium (PTCTC) and MD Anderson Cancer Center CAR T Cell Therapy-Associated Toxicity (CARTOX) Program collaborated to provide updated comprehensive recommendations for the care of children, adolescents and young adults receiving cancer immunotherapies. With these recommendations, we address emerging toxicity mitigation strategies, we advocate for the characterization of baseline organ function according to age and discipline-specific criteria, we recommend early critical care assessment when indicated, with consideration of reversibility of underlying pathology (instead of organ failure scores) to guide critical care interventions, and we call for researchers, regulatory agencies and sponsors to support and facilitate early inclusion of young patients with cancer in well-designed clinical trials.

Predicting Failure of Non-Invasive Ventilation With RAM Cannula in Bronchiolitis

INTRODUCTION

In infants hospitalized for bronchiolitis on non-invasive ventilation (NIV) via the RAM cannula nasal interface, variables predicting subsequent intubation, or NIV non-response, are understudied. We sought to identify predictors of NIV non-response.

METHODS

We performed a retrospective cohort study in infants admitted for respiratory failure from bronchiolitis placed on NIV in a quaternary children's hospital. We excluded children with concurrent sepsis, critical congenital heart disease, or with preexisting tracheostomy. The primary outcome was NIV non-response defined as intubation after a trial of NIV. Secondary outcomes were vital sign values before and after NIV initiation, duration of NIV and intubation, and mortality. Primary analyses included Chi-square, Wilcoxon rank-sum, student's t test, paired analyses, and adjusted and unadjusted logistic regression assessing heart rate (HR) and respiratory rate (RR) before and after NIV initiation.

RESULTS

Of 138 infants studied, 34% were non-responders. There were no differences in baseline characteristics of responders and non-responders. HR decreased after NIV initiation in responders (156 [143-156] to149 [141-158], p < 0.01) compared to non-responders (158 [149-166] to 158 [145-171], p = 0.73). RR decreased in responders (50 [43-58] vs 47 [41-54]) and non-responders (52 [48-58] vs 51 [40-55], both p < 0.01). Concurrent bacterial pneumonia (OR 6.06, 95% CI: 2.54-14.51) and persistently elevated HR (OR: 1.04, 95% CI: 1.01-1.07) were associated with NIV non-response.

CONCLUSION

In children with acute bronchiolitis who fail to respond to NIV and require subsequent intubation, we noted associations with persistently elevated HR after NIV initiation and concurrent bacterial pneumonia.

Impact of flow and temperature on non-dyspnoeic dogs' tolerance undergoing high-flow oxygen therapy

OBJECTIVES

To prospectively describe the impact of gas flow rate and temperature on dog's tolerance of high-flow nasal oxygen therapy during recovery from anaesthesia, hypothesizing that higher flow rates and temperatures will decrease tolerance.

MATERIALS AND METHODS

Twelve non-dyspnoeic client-owned dogs recovering from general anaesthesia were included in this study. After extubation, a nasal cannula was positioned and high-flow nasal oxygen therapy was initiated. Two flow rates (two or four time the theoretical minute ventilation: HF2 and HF4), each of them combined with two temperatures (31 and 37°C: T31 and T37), were randomly applied (four conditions per dog). For each condition, cardiovascular and respiratory parameters (heart rate, respiratory rate, systolic arterial blood pressure and pulse oximeter oxygen saturation), sedation score and tolerance score were recorded at initiation (T₀ ) and after 10 minutes of accommodation (T₁₀ ).

RESULTS

Sedation scores were not significantly different between the four conditions. Cardiovascular and respiratory parameters were not significantly different between any condition at both T₀ and T₁₀ . Tolerance scores were good and not significantly different between any flow rate or temperature (HF2-T31: 4 (2-4), HF4-T31: 4 (2-4), HF2-T37: 4 (2-4), HF4-T37: 4 (1-4)).

CLINICAL SIGNIFICANCE

The gas flow rates and temperatures studied have no impact on tolerance during the recovery period of non-dyspnoeic dogs, and high-flow nasal cannula is well tolerated. Further studies are required to confirm these results in dyspnoeic dogs.

High-Flow Nasal Cannula Use Outside of the ICU Setting

OBJECTIVES

To describe the practice of high-flow nasal cannula (HFNC) use in the pediatric ward setting across North America.

METHODS

A survey was distributed through the Pediatric Research in Inpatient Settings Network, which represents 114 hospital sites. Questions included indication for HFNC use, flow and oxygen parameters, guideline availability, and use of outcomes measures.

RESULTS

There was a response rate of 68% to the survey from sites representing all regions from the United States. Thirty-seven sites (48%) used HFNC in the pediatric ward setting. All 37 sites used HFNC for patients with bronchiolitis. All children's hospital sites providing HFNC on the wards had an on-site ICU, compared with only 60% of non-children's hospital sites (P = .003). Seventy-six percent of sites used local protocols, including parameters for patient assessment, initiation, weaning, and feeding practices.

CONCLUSIONS

HFNC is used outside the ICU in nearly 50% of responding hospitals, with variation related to flow rate, feeding, and protocol use. HFNC is used for management of acute respiratory distress due to bronchiolitis, asthma, and pneumonia. Study findings suggest that HFNC is often used by pediatric hospitalists, but its use across North American hospitals remains variable and based on local consensus.

Nasogastric tube, a warning sign for high-flow nasal cannula failure in infants with bronchiolitis

High-flow nasal cannula (HFNC) therapy is routinely used in the treatment of infants with bronchiolitis. This study sought to identify markers associated with failure of HFNC therapy that serve as warnings for early staging of other ventilatory support products. A retrospective study of infants with a diagnosis of bronchiolitis, receiving HFNC and admitted to the pediatric intensive care unit from January 2016 to June 2017, was conducted. The subjects were divided into two study groups according to the success or failure of HFNC therapy. Risk factors were assessed using the following variables: age, time between hospital admission and start of HFNC, equipment model, and the need for a nasogastric tube. Eighty-one infants were studied, and 18 (21.7%) of them exhibited therapy failure. The results of the logistic models showed that the chances of failure for patients requiring a nasogastric tube during HFNC use were more likely than those for patients with oral nutrition (OR = 8.17; 95% CI 2.30–28.99; p = 0.001). The HFNC failure was not associated with the device used (OR = 1.56; 95% CI 0.54–4.52; p = 0.41), time between hospital admission and HFNC installation (OR = 1.01; 95% CI 0.98–1.03; p = 0.73), or age (OR = 0.98; 95% CI 0.82–1.17; p = 0.82). Among late outcomes evaluated, the patients with therapy failure had longer total durations of O₂ use (p < 0.001) and longer hospital stays (p < 0.001). The need to use a nasogastric tube during HFNC use was associated with HFNC therapy failure and can be considered as a marker of severity in children with bronchiolitis.

A narrative review on trans-nasal pulmonary aerosol delivery

The use of trans-nasal pulmonary aerosol delivery via high-flow nasal cannula (HFNC) has expanded in recent years. However, various factors influencing aerosol delivery in this setting have not been precisely defined, and no consensus has emerged regarding the optimal techniques for aerosol delivery with HFNC. Based on a comprehensive literature search, we reviewed studies that assessed trans-nasal pulmonary aerosol delivery with HFNC by in vitro experiments, and in vivo, by radiolabeled, pharmacokinetic and pharmacodynamic studies. In these investigations, the type of nebulizer employed and its placement, carrier gas, the relationship between gas flow and patient’s inspiratory flow, aerosol delivery strategies (intermittent unit dose vs continuous administration by infusion pump), and open vs closed mouth breathing influenced aerosol delivery. The objective of this review was to provide rational recommendations for optimizing aerosol delivery with HFNC in various clinical settings.

Intensive Care Unit Utilization After Adoption of a Ward-Based High-Flow Nasal Cannula Protocol

BACKGROUND

Hospitals are increasingly adopting ward-based high-flow nasal cannula (HFNC) protocols that allow HFNC treatment of bronchiolitis outside of the intensive care unit (ICU). Our objective was to determine whether adoption of a ward-based HFNC protocol reduces ICU utilization.

METHODS

We examined a retrospective cohort of infants aged 3 to 24 months hospitalized with bronchiolitis at hospitals in the Pediatric Health Information System database. The study exposure was adoption of a ward-based HFNC protocol, measured by direct contact with pediatric hospital medicine leaders at each hospital. All analyses utilized an interrupted time series approach. The primary analysis compared outcomes three respiratory seasons before and three respiratory seasons after HFNC adoption, among adopting hospitals. Supplementary analysis 1 mirrored the primary analysis with the exception that the first season after adoption was censored. In supplementary analysis 2, effects among nonadopting hospitals were subtracted from effects measured among adopting hospitals.

RESULTS

Of 44 contacted hospitals, 41 replied (93% response rate), of which 18 were categorized as non-adopting hospitals and 12 were categorized as adopting hospitals. Included ward-based HFNC protocols were adopted between the 2010-2011 and 2015-2016 respiratory seasons. The primary analysis included 26,253 bronchiolitis encounters and measured immediate increases in the proportion of patients admitted to the ICU (absolute difference, 3.1%; 95% CI, 2.8%-3.4%) and ICU length of stay (absolute difference, 9.1 days per 100 patients; 95% CI, 5.1-13.2). Both supplementary analyses yielded similar findings.

CONCLUSION

Early protocols for ward-based HFNC were paradoxically associated with increased ICU utilization.

Monitoring of Respiratory Muscle Function in Critically Ill Children

OBJECTIVES

This review discusses the different techniques used at the bedside to assess respiratory muscle function in critically ill children and their clinical applications.

DATA SOURCES

A scoping review of the medical literature on respiratory muscle function assessment in critically ill children was conducted using the PubMed search engine.

STUDY SELECTION

We included all scientific, peer-reviewed studies about respiratory muscle function assessment in critically ill children, as well as some key adult studies.

DATA EXTRACTION

Data extracted included findings or comments about techniques used to assess respiratory muscle function.

DATA SYNTHESIS

Various promising physiologic techniques are available to assess respiratory muscle function at the bedside of critically ill children throughout the disease process. During the acute phase, this assessment allows a better understanding of the pathophysiological mechanisms of the disease and an optimization of the ventilatory support to increase its effectiveness and limit its potential complications. During the weaning process, these physiologic techniques may help predict extubation success and therefore optimize ventilator weaning.

CONCLUSIONS

Physiologic techniques are useful to precisely assess respiratory muscle function and to individualize and optimize the management of mechanical ventilation in children. Among all the available techniques, the measurements of esophageal pressure and electrical activity of the diaphragm appear particularly helpful in the era of individualized ventilatory management.

High-Flow Nasal Cannula versus Continuous Positive Airway Pressure in Critical Bronchiolitis: A Randomized Controlled Pilot

We conducted a randomized controlled pilot study in infants with critical bronchiolitis ( n  = 63) comparing high-flow nasal cannula (HFNC, n  = 35) to continuous positive airway pressure (CPAP, n  = 28). The primary outcome was treatment failure, defined as the need for bilevel positive pressure ventilation or endotracheal intubation. Treatment failure occurred in 10 patients (35.7%) in the CPAP group and 13 patients (37.1%) in the HFNC group ( p  = 0.88). Pediatric intensive care unit length of stay was similar between the CPAP and HFNC groups (5 [4-7] days and 5 [4-8] days, p  = 0.46, respectively). In this pilot study, treatment with HFNC resulted in a rate of treatment failure similar to CPAP.

Mechanisms of nasal high flow therapy in newborns

In newborns, it is unclear how nasal high flow (NHF) generates positive airway pressure. In addition, the reported benefits of NHF such as reduction in work of breathing may be independent of airway pressure. The authors hypothesized that during NHF the area of leak and the flow determine airway pressure and that NHF can reduce the required minute ventilation to maintain gas exchange. In response to NHF, pressure was measured in the upper airways of 9 newborns and ventilation was measured in another group of 17 newborns. In a bench model, airway pressures were measured during NHF with different prong sizes, nare sizes, and flows. The airway pressures during 8 L/min NHF were greater when a larger cannula versus a smaller cannula was used (P < 0.05). NHF reduced minute ventilation in 16 of 17 neonates, with a mean decrease of 24% from a baseline of 0.66 L/min (SD 0.21) (P < 0.001), and was unrelated to changes in airway pressure; arterial oxygen saturation by pulse oximetry (SpO2) and tissue CO₂ were unchanged. In the bench model, the airway pressure remained <2 cmH₂O when <50% of the “nare” was occluded by the prongs. As the leak area decreased, because of a smaller nare or a larger cannula, the airway pressure increased exponentially and was dependent on flow. In newborns NHF using room air substantially reduced minute ventilation without affecting gas exchange irrespective of a decrease or an increase of respiratory rate. NHF generates low positive airway pressure that exponentially increases with flow and occlusion of the nares.

NEW & NOTEWORTHY In healthy newborns, nasal high flow (NHF) with room air reduced minute ventilation by one-fourth without affecting gas exchange but, in contrast to adults, produced variable response in respiratory rate during sleep. During NHF, pressure in the upper airways did not exceed 2 cmH₂O at 8 L/min (3.4 L·min⁻¹·kg⁻¹) and was unaffected by opening of the mouth. NHF can generate higher pressure with larger prongs that decrease the leak around the cannula or by increasing the flow rate.

In vitro comparison of unit dose vs infusion pump administration of albuterol via high-flow nasal cannula in toddlers

OBJECTIVES

Transnasal pulmonary aerosol delivery using high-flow nasal cannula (HFNC) devices has become a popular route of aerosol administration in toddlers. Clinically, albuterol is administered using an infusion pump or unit doses. However, little evidence is available to compare the two administration strategies.

METHODS

A toddler manikin (15 kg) with appropriate anatomic airway was connected with collecting filter to a simulator of distressed breathing. HFNC device with mesh nebulizer placed at the inlet of a humidifier at 37°C, with the gas flow set at 25 and 3.75 L/min. Five milligrams of albuterol was delivered in all experiments. With infusion pump administration, albuterol concentrations of 5 and 1 mg/mL were delivered at 4 and 20 mL/hr for 15 minutes. With unit dose administration, 1 mL (5 mg/mL) and 2 mL (2.5 mg/mL) of albuterol were nebulized. Additional tests with mouth open and nebulizers via mask were using 5 mg/1 mL for mesh nebulizer and 5 mg/3 mL for jet nebulizer (n = 3). The drug was eluted from the filter and assayed with UV spectrophotometry (276 nm).

RESULTS

The inhaled dose was higher with unit dose than infusion pump administration with gas flows of 25 L/min (2.66 ± 0.38 vs 1.16 ± 0.28%; P = .004) and 3.75 L/min (10.51 ± 1.29 vs 8.58 ± 0.68%; P = .025). During unit dose administration, compared with closed-mouth breathing, open-mouth breathing generated a higher inhaled dose at 3.75 L/min and lower inhaled dose at 25 L/min. Compared to the nebulizers via mask with both open and closed-mouth breathing, nebulization via HFNC at 3.75 L/min generated greater inhaled dose, while HFNC at 25 L/min generated lower inhaled dose.

CONCLUSIONS

During transnasal aerosol delivery, the inhaled dose was higher with medication administrated using unit dose than using an infusion pump.

[Factors associated to high-flow nasal cannula treatment failure in pediatric patients with respiratory failure in two pediatric intensive care units at high altitude]

INTRODUCTION

Acute respiratory failure is the leading cause of hospitalization in pediatrics. High-flow nasal cannulas (HFNCs) offer a new alternative, but the evidence and indications are still debated. The performance of HFNCs at high altitude has not been described to date.

OBJECTIVE

To describe the use of HFNCs in pediatric patients admitted with respiratory failure and explore the factors associated with treatment failure.

METHODOLOGY

A prospective cohort study was carried out in patients between 1 month and 18 years of age managed with HFNCs. The demographic and treatment response data were recorded at baseline and after 1, 6 and 24hours. The number of failures was determined, as well as the length of stay, complications and mortality. Patients with treatment failure were compared with the rest.

RESULTS

A total of 539 patients were enrolled. Infants (70.9%) of male sex (58.4%) and airway diseases such as asthma and bronchiolitis (61.2%) were more frequent. There were 53 failures (9.8%), with 21 occurring in the first 24hours. The median length of stay was 4 days (IQR 4); there were 5 deaths (0.9%) and 13 adverse events (epistaxis) (2.2%). Improvement was observed in vital signs and severity over time, with differences in the group that failed, but without interactions. The final logistic model established an independent relationship of failure between the hospital (OR 2.78, 95%CI 1.48-5.21) and the initial respiratory rate (OR 1.56, 95%CI 1.21-2.01).

CONCLUSIONS

HFNCs afford good clinical response, with few complications and a low failure rate. The differences found between institutions suggest a subjective relationship in the decision of therapy failure.

A Phase II randomized controlled trial for lung and diaphragm protective ventilation (Real-time Effort Driven VENTilator management)

Lung Protective Mechanical Ventilation (MV) of critically ill adults and children is lifesaving but it may decrease diaphragm contraction and promote Ventilator Induced Diaphragm Dysfunction (VIDD). An ideal MV strategy would balance lung and diaphragm protection. Building off a Phase I pilot study, we are conducting a Phase II controlled clinical trial that seeks to understand the evolution of VIDD in critically ill children and test whether a novel computer-based approach (Real-time Effort Driven ventilator management (REDvent)) can balance lung and diaphragm protective ventilation to reduce time on MV. REDvent systematically adjusts PEEP, FiO₂, inspiratory pressure, tidal volume and rate, and uses real-time measures from esophageal manometry to target normal levels of patient effort of breathing. This trial targets 276 children with pulmonary parenchymal disease. Patients are randomized to REDvent vs. usual care for the acute phase of MV (intubation to first Spontaneous Breathing Trial (SBT)). Patients in either group who fail their first SBT will be randomized to REDvent vs usual care for weaning phase management (interval from first SBT to passing SBT). The primary clinical outcome is length of weaning, with several mechanistic outcomes. Upon completion, this study will provide important information on the pathogenesis and timing of VIDD during MV in children and whether this computerized protocol targeting lung and diaphragm protection can lead to improvement in intermediate clinical outcomes. This will form the basis for a larger, Phase III multi-center study, powered for key clinical outcomes such as 28-day ventilator free days. Clinical Trials Registration: NCT03266016.

Comparison of heated humidified high-flow nasal cannula flow rates (1-L·kg·min-1 vs 2-L·kg·min -1 ) in the management of acute bronchiolitis

OBJECTIVE

We aimed to compare the heated humidified high-flow nasal cannula (HHHFNC) flow rate of 1-L·kg·min^-1 (1 L) with 2-L·kg·min ^-1 (2 L) in patients with severe bronchiolitis presenting to the pediatric emergency department.

STUDY DESIGN

We performed a study in which all patients were allocated to receive these two flow rates. The primary outcome was admitted as treatment failure, which was defined as a clinical escalation in respiratory status. Secondary outcomes covered a decrease of respiratory rate (RR), heart rate (HR), the clinical respiratory score (CRS), rise of peripheral capillary oxygen saturation (SpO₂ ), and rates of weaning, intubation, and intensive care unit (ICU) admission.

RESULTS

One hundred and sixty-eight cases (88 received the 1-L flow rate and 80, the 2-L flow rate) were included in the analyses. Treatment failure was 11.4% (10 of 88) in the 1-L group, and 10% (8 of 80) in the 2-L group (P = .775). Significant variation in the intubation rate or the ICU admission rate was not determined. At the 2nd hour, the rate of weaning (53.4% vs 35%; P = .017), the falling down of the CRS (-2.1 vs -1.5; P < .001), RR (-15.2 vs -11.8; P < .001), and HR (- 24.8 vs - 21.2; P < .001), and the increase of SpO ₂ (4.8 vs 3.6; P < .001) were significantly more evident in the 1-L group.

CONCLUSION

HHHFNC with the 1-L·kg·min^-1 flow rate, which provides a more frequent earlier effect, reached therapy success as high as the 2-L·kg·min ^-1 flow rate in patients with severe acute bronchiolitis.

Decrease the flow setting to improve trans-nasal pulmonary aerosol delivery via "high-flow nasal cannula" to infants and toddlers

OBJECTIVES

Trans-nasal pulmonary aerosol delivery for infants and toddlers has recently gained popularity, however, the reported lung deposition is low. We aimed to investigate the influential factors to improve the delivery.

METHODS

Anatomic airway manikins simulating infant (5 kg) and toddler (15 kg) with collecting filter connected the trachea and breath simulator, were set to represent quiet and distressed breathing. Nasal cannula flow was set at 0.125, 0.25, 0.5, 1, and 2 L/kg/min. A mesh nebulizer (Aerogen) was placed at the inlet of humidifier (Fisher & Paykel) and proximal to patient. Albuterol (5 mg in 1 mL) was nebulized for each condition (n = 3). Drug was eluted from the filter and assayed with UV spectrophotometry (276 nm).

RESULTS

Inhaled dose was higher with nebulizer placed at the inlet of humidifier than proximal to patient in all settings, except the infant model at low gas flow settings (0.125 and 0.25 L/kg/min). When nebulizer was placed at the inlet of humidifier, inhaled dose was higher when gas flow was below patient's inspiratory flow than when gas flow exceeded patient's inspiratory flow (8.77 ± 3.84 vs 2.16 ± 1.29%, P < 0.001); aerosol deposition increased as gas flow decreased, with greatest deposition at gas flow of 0.25 L/kg/min (11.29 ± 2.15%). A multiple linear regression identified gas flow as the primary predictor of aerosol delivery.

CONCLUSIONS

Trans-nasal pulmonary aerosol delivery was significantly improved when gas flow was below patient's inspiratory flow, aerosol deposition increased with decreased nasal cannula flow, with greatest deposition at 0.25 L/kg/min.

Patterns of Use of Heated Humidified High-Flow Nasal Cannula Therapy in PICUs in the United Kingdom and Republic of Ireland

OBJECTIVES

To 1) describe patterns of use of high-flow nasal cannula therapy, 2) examine differences between patients started on high-flow nasal cannula and those started on noninvasive ventilation, and 3) explore whether patients who failed high-flow nasal cannula therapy were different from those who did not.

DESIGN

Retrospective analysis of data collected prospectively by the Paediatric Intensive Care Audit Network.

SETTING

All PICUs in the United Kingdom and Republic of Ireland (n = 34).

PATIENTS

Admissions to study PICUs (2015-2016) receiving any form of respiratory support at any time during PICU stay.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Eligible admissions were classified into nine groups based on the combination of the first-line and second-line respiratory support modes. Uni- and multivariate analyses were performed to test the association between PICU and patient characteristics and two outcomes: 1) use of high-flow nasal cannula versus noninvasive ventilation as first-line mode and 2) high-flow nasal cannula failure, requiring escalation to noninvasive ventilation and/or invasive ventilation. We analyzed data from 26,423 admissions; high-flow nasal cannula was used in 5,951 (22.5%) at some point during the PICU stay. High-flow nasal cannula was used for first-line support in 2,080 (7.9%) and postextubation support in 978 admissions (4.5% of patients extubated after first-line invasive ventilation). High-flow nasal cannula failure occurred in 559 of 2,080 admissions (26.9%) when used for first-line support. Uni- and multivariate analyses showed that PICU characteristics as well as patient age, primary diagnostic group, and admission type had a significant influence on the choice of first-line mode (high-flow nasal cannula or noninvasive ventilation). Younger age, unplanned admission, and higher admission severity of illness were independent predictors of high-flow nasal cannula failure.

CONCLUSIONS

The use of high-flow nasal cannula is common in PICUs in the United Kingdom and Republic of Ireland. Variation in the choice of first-line respiratory support mode (high-flow nasal cannula or noninvasive ventilation) between PICUs reflects the need for clinical trial evidence to guide future practice.

Critical Care in the Pediatric Emergency Department

In caring for critically ill children, recognition and management often begins in the pediatric emergency department. A seamless transition in care is needed to ensure appropriate care to the sickest of children. This review covers the management of critically ill children in the pediatric emergency department beyond the initial stabilization for conditions such as acute respiratory failure and pediatric acute respiratory distress syndrome, traumatic brain injury, status epilepticus, congenital heart disease, and metabolic emergencies.

High flow nasal cannula in the emergency department: indications, safety and effectiveness

INTRODUCTION

Heated humidified high flow nasal cannula therapy (HHHFNCT) is emerging as a popular non-invasive mode of respiratory support in adults and children. In recent years, its use has extended beyond the intensive care unit to other clinical areas. This review aims to explore the mechanism of action, indications, safety, and effectiveness of HHHFNCT use in the Emergency Department (ED).

AREAS COVERED

The mechanism of action of HHHFNCT, as well as its use in adult and pediatric ED will be discussed in this review.

EXPERT COMMENTARY

While there exists increasing enthusiasm in the use of HHHFNCT in the ED, constant monitoring of the patients and an experienced assessment of their response to treatment are critical and may require additional manpower deployment, which may be challenging, in the busy ED environment. Our experience with the use of HHHFNCT in children is still growing. Continual research in this area remains crucial in helping us better understand the patient types and conditions managed in ED that would most benefit from this device.

Using high-flow nasal cannulas for infants with bronchiolitis admitted to paediatric wards is safe and feasible

AIM

Using a high-flow nasal cannula (HFNC) for infant bronchiolitis is increasingly common, but insufficiently studied. In this retrospective study, we examined the outcomes of HFNC and compared infants who did and did not respond to this oxygen delivery method.

METHODS

This 2012-2015 study of six Finnish hospitals focused on 88 infants under 12 months who received HFNC: 53 on paediatric wards and 35 in paediatric intensive care units (PICUs). We reviewed patient files for underlying factors, clinical parameters and HFNC treatment. The treatment failed if the patient was transferred to another respiratory support.

RESULTS

We found HFNC treatment was successful in 76 (86%) infants, including all 53 on the paediatric wards and 23/35 PICU patients. The responders' heart rates were significantly lower, and their oxygen saturation was significantly higher at 60 minutes after HFNC treatment started and then stayed relatively constant. Their respiratory rate was only significantly lower after 360 minutes. In non-responders, the respiratory rate initially decreased but was higher at 180 and 360 minutes after the start of HFNC.

CONCLUSION

We found preliminary evidence that oxygen support needs and heart rate were useful early predictors of HFNC therapy success in infants hospitalised with bronchiolitis, but respiratory rate was not.