A multicenter randomized controlled trial of a 3-L/kg/min versus 2-L/kg/min high-flow nasal cannula flow rate in young infants with severe viral bronchiolitis (TRAMONTANE 2)

Single centre observational study evaluating the impact of introducing High Flow Nasal Cannula outside of Paediatric Critical Care Unit

AIM

To evaluate the impact of High Flow Nasal Cannula (HFNC) introduction outside of Paediatric Critical Care Units (PCCU), on PCCU admissions and intubation rates. Secondarily, to identify escalation predictors.

METHODS

Retrospective observational study with matched PCCU admissions and intubation rates, 2-years before (Group 1) and 2-years after (Group 2) HFNC introduction outside of PCCU. Within Group 2, we compared those admitted to PCCU (escalation) and those who did not (non-escalation). Observations, change in observations and time to starting HFNC were analysed.

RESULTS

Pre- and post-introduction comparison: Of 980 admissions in Group 1, 55 were admitted to PCCU, whereas of 1209 admission in Group 2, there were 85 admissions, P = 0.188. Group 1 had 25 intubations compared to 23 in Group 2, P = 0.309. Over twice as many children had some form of respiratory support in Group 2. Post-introduction: 104 children commenced HFNC, 72% for bronchiolitis. Median age was 4 months in the non-escalation group and 6.5 months in the escalation group, P = 0.663. Thirty-eight children escalated to PCCU: 33 required CPAP/BiPAP, 4 were intubated with 1 remaining on HFNC. Comparisons of age, gender, comorbidities, observations, change in observations and time to starting HFNC showed no significant escalation predictors.

CONCLUSIONS

This study identified no statistically significant predictors of escalation. There was an observed increase in PCCU admissions with decreased intubations. The resource implications of this therapy are significant and further studies should examine cost effectiveness of HFNC use outside of PCCU.

Effectiveness of high flow nasal Cannula (HFNC) therapy compared to standard oxygen therapy (SOT) and continuous positive airway pressure (CPAP) in bronchiolitis

High Flow Nasal Cannula therapy (HFNC) is a form of respiratory support for bronchiolitis. Recent evidence confirms HFNC reduces the risk of treatment escalation by nearly half (45%) compared to standard oxygen therapy (SOT), although most patients (75%) with mild-moderate respiratory distress manage well on SOT. The majority of children (60%) failing SOT respond well to HFNC making rescue use of HFNC a more cost-effective approach compared to its first-line use. HFNC is compared toCPAP in the setting of moderate to severe bronchiolitis. Patients on HFNC have a slightly elevated risk of treatment failure especially in severe bronchiolitis, but this does not translate to a significant difference in patient or healthcare centred outcomes. HFNC has improved tolerance, a lower complication rate and is more easily available in peripheral hospitals. It is therefore the preferred first line option followed by rescue CPAP. HFNC is clinically effective and safe to use in bronchiolitis of all severities.

Addressing high flow overuse in bronchiolitis - Successes and future directions

The use of high flow nasal cannula (HFNC) in the treatment of bronchiolitis has markedly increased in the last decade, yet randomized controlled trials have reported little clinical benefit with early, routine use. This article provides a concise overview of the current status of HFNC therapy, discusses successful de-implementation strategies to curtail HFNC overuse, and explores future bronchiolitis and HFNC quality improvement and research considerations.

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.

High-flow nasal cannula therapy for infants with bronchiolitis

BACKGROUND

Bronchiolitis is a common lower respiratory tract illness, usually of viral aetiology, affecting infants younger than 24 months of age and is the most common cause of hospitalisation of infants. It causes airway inflammation, mucus production and mucous plugging, resulting in airway obstruction. Effective pharmacotherapy is lacking and bronchiolitis is a major cause of morbidity and mortality. Conventional treatment consists of supportive therapy in the form of fluids, supplemental oxygen, and respiratory support. Traditionally, oxygen delivery is as a dry gas at 100% concentration via low-flow nasal prongs. However, the use of heated, humidified, high-flow nasal cannula (HFNC) therapy enables delivery of higher inspired gas flows of an air/oxygen blend, at 2 to 3 L/kg per minute up to 60 L/min in children. It can provide some level of continuous positive airway pressure (CPAP) to improve ventilation in a minimally invasive manner. This may reduce the need for invasive respiratory support, thus potentially lowering costs, with clinical advantages and fewer adverse effects.

OBJECTIVES

To assess the effects of HFNC therapy compared with conventional respiratory support in the treatment of infants with bronchiolitis.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, LILACS, and Web of Science (from June 2013 to December 2022). In addition, we consulted ongoing trial registers and experts in the field to identify ongoing studies, checked reference lists of relevant articles, and searched for conference abstracts. Date restrictions were imposed such that we only searched for studies published after the original version of this review.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) or quasi-RCTs that assessed the effects of HFNC (delivering oxygen or oxygen/room air blend at flow rates greater than 4 L/minute) compared to conventional treatment in infants (< 24 months) with a clinical diagnosis of bronchiolitis.

DATA COLLECTION AND ANALYSIS

Two review authors independently used a standard template to assess trials for inclusion and extract data on study characteristics, risk of bias elements, and outcomes. We contacted trial authors to request missing data. Outcome measures included the need for invasive respiratory support and time until discharge, clinical severity measures, oxygen saturation, duration of oxygen therapy, and adverse events.

MAIN RESULTS

In this update we included 15 new RCTs (2794 participants), bringing the total number of RCTs to 16 (2813 participants). Of the 16 studies, 11 compared high-flow to low-flow, and five compared high-flow to CPAP. These studies included infants less than 24 months of age as stated in our selection criteria. There were no significant differences in sex. We found that when comparing high-flow to low-flow oxygen therapy for infants with bronchiolitis there may be a reduction in the total length of hospital stay (mean difference (MD) -0.65 days, 95% confidence interval (CI) -1.23 to -0.06; P < 0.00001, I2 = 89%; 7 studies, 1951 participants; low-certainty evidence). There may also be a reduction in the duration of oxygen therapy (MD -0.59 days, 95% CI -1 to -0.18; P < 0.00001, I2 = 86%; 7 studies, 2132 participants; low-certainty evidence). We also found that there was probably an improvement in respiratory rate at one and 24 hours, and heart rate at one, four to six, and 24 hours in those receiving high-flow oxygen therapy when compared to pre-intervention baselines. There was also probably a reduced risk of treatment escalation in those receiving high-flow when compared to low-flow oxygen therapy (risk ratio (RR) 0.55, 95% CI 0.39 to 0.79; P = 0.001, I2 = 43%; 8 studies, 2215 participants; moderate-certainty evidence). We found no difference in the incidence of adverse events (RR 1.2, 95% CI 0.38 to 3.74; P = 0.76, I2 = 26%; 4 studies, 1789 participants; low-certainty evidence) between the two groups. The lack of comparable outcomes in studies comparing high-flow and CPAP, as well as the small numbers of participants, limited our ability to perform meta-analysis on this group.

AUTHORS' CONCLUSIONS

High-flow nasal cannula therapy may have some benefits over low-flow oxygen for infants with bronchiolitis in terms of a greater improvement in respiratory and heart rates, as well as a modest reduction in the length of hospital stay and duration of oxygen therapy, with a reduced incidence of treatment escalation. There does not appear to be a difference in the number of adverse events. Further studies comparing high-flow nasal cannula therapy and CPAP are required to demonstrate the efficacy of one modality over the other. A standardised clinical definition of bronchiolitis, as well as the use of a validated clinical severity score, would allow for greater and more accurate comparison between studies.

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.

High-flow oxygen therapy in moderate to severe bronchiolitis: a randomised controlled trial

BACKGROUND AND OBJECTIVE

High-flow (HF) oxygen therapy is being used increasingly in infants with bronchiolitis, despite lack of convincing evidence of its superiority over low flow (LF). We aimed to compare the effect of HF to LF in moderate to severe bronchiolitis.

METHODS

Multicentre randomised controlled trial during four winter seasons (2016-2020) including 107 children under 2 years of age admitted with moderate to severe bronchiolitis, oxygen saturation of <92% and severely impaired vital signs. Crossovers were not allowed. HF was administered at flow rates of 2 L/kg for the first 10 kg, plus 0.5 L/kg for every kg >10 kg, LF with a maximum flow rate of 3 L/min. Primary outcome was improvement of vital signs and dyspnoea severity within 24 hours assessed by a composite score. Secondary outcomes were comfort, duration of oxygen therapy, supplemental feedings, hospitalisation duration and intensive care admission for invasive ventilation.

RESULTS

Significant improvement within 24 hours occurred in 73% of 55 patients randomised to HF and in 78% of 52 patients with LF (difference 6%, 95% CI -13% to 23%). Intention-to-treat analysis revealed no significant differences in any secondary outcome: duration of oxygen therapy, supplemental feedings, hospitalisation and need for invasive ventilation or intensive care admission, except for comfort (face, legs, activity, cry, consolability), which was one point (out of a scale of 0-10) higher in the LF group. No adverse effects occurred.

CONCLUSION

We found no measurable clinically relevant benefit in the use of HF compared with LF in hypoxic children with moderate to severe bronchiolitis.

TRIAL REGISTRATION NUMBER

NCT02913040.

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.

Respiratory effort during noninvasive positive pressure ventilation and continuous positive airway pressure in severe acute viral bronchiolitis

OBJECTIVES

To assess if noninvasive positive pressure ventilation (NIPPV) is associated with a greater reduction in respiratory effort as compared to continuous positive airway pressure (CPAP) during severe acute bronchiolitis, with both supports set either clinically or physiologically.

METHODS

Twenty infants (median [IQR] age 1.2 [0.9; 3.2] months) treated <24 h with noninvasive respiratory support (CPAP Clin, set at 7 cmH₂ O, or NIPPV Clin) for bronchiolitis were included in a prospective single-center crossover study. Esogastric pressures were measured first with the baseline support, then with the other support. For each support, recordings were performed with the clinical setting and a physiological setting (CPAP Phys and NIPPV Phys), aiming at normalising respiratory effort. Patients were then treated with the optimal support. The primary outcome was the greatest reduction in esophageal pressure-time product (PTP_ES /min). Other outcomes included improvement of the other components of the respiratory effort.

RESULTS

NIPPV Clin and Phys were associated with a lower PTP_ES /min (164 [105; 202] and 106 [78; 161] cmH₂ O s/min, respectively) than CPAP Clin (178 [145; 236] cmH₂ O s/min; p = 0.01 and 2 × 10^-4 , respectively). NIPPV Clin and Phys were also associated with a significant reduction of all other markers of respiratory effort as compared to CPAP Clin. PTP_ES /min with NIPPV (Clin or Phys) was not different from PTP_ES /min with CPAP Phys. There was no significant difference between physiological and clinical settings.

CONCLUSION

NIPPV is associated with a significant reduction in respiratory effort as compared to CPAP set at +7 cmH₂ O in infants with severe acute bronchiolitis. CPAP Phys performs as well as NIPPV Clin.

Effects of Chest Physiotherapy in Preterm Infants with Respiratory Distress Syndrome: A Systematic Review

Preterm birth carries a higher risk of respiratory problems. The objectives of the study are to summarize the evidence on the effect of chest physiotherapy in the treatment of respiratory difficulties in preterm infants, and to determine the most appropriate technique and whether they are safe. Searches were made in PubMed, WOS, Scopus, Cochrane Library, SciELO, LILACS, MEDLINE, ProQuest, PsycArticle and VHL until 30 April 2022. Eligibility criteria were study type, full text, language, and treatment type. No publication date restrictions were applied. The MINCIR Therapy and PEDro scales were used to measure the methodological quality, and the Cochrane risk of bias and Newcastle Ottawa quality assessment Scale to measure the risk of bias. We analysed 10 studies with 522 participants. The most common interventions were conventional chest physiotherapy and stimulation of the chest zone according to Vojta. Lung compression and increased expiratory flow were also used. Heterogeneities were observed regarding the duration of the interventions and the number of participants. The methodological quality of some articles was not adequate. All techniques were shown to be safe. Benefits were described after conventional chest physiotherapy, Vojta's reflex rolling, and lung compression interventions. Improvements after Vojta's reflex rolling are highlighted in the comparative studies.

Advances in Management of Respiratory Failure in Children

Providing the right respiratory support is an essential skill, vital for anyone treating sick children. Recent advances in respiratory support include developments in both non-invasive and invasive ventilatory strategies. In non-invasive ventilation, newer modalities are being developed, in an attempt to decrease the need for invasive ventilation. This include newer techniques like Heated humidified high-flow nasal cannula (HHHFNC) and improvements in existing modes. The success of Continuous positive airway pressure (CPAP) and other non-invasive modes depend to a large extent on choosing and maintaining a suitable interface. When it comes to invasive ventilation, recent advances are focussing on increasing automation, improving patient comfort and minimising lung injury. Concepts like mechanical power are attempts at understanding the mechanisms of unintended injuries resulting from respiratory support and newer monitoring methods like transpulmonary pressure, thoracic impedance tomography are attempts at measuring potential markers of lung injury. Using the vast arrays of available ventilatory options judiciously, considering their advantages and drawbacks in every individual case will be the prime responsibility of clinicians in the future. Simultaneously, efforts have been made to identify potential drugs that can favourably modify the pathophysiology of acute respiratory distress syndrome (ARDS). Unfortunately, though eagerly awaited, most pharmaceutical agents tried in pediatric ARDS have not shown definite benefit. Pulmonary local drug and gene therapy using liquid ventilation strategies may revolutionize our future understanding and management of lung diseases.

High-Flow Oxygen and Other Noninvasive Respiratory Support Therapies in Bronchiolitis: Systematic Review and Network Meta-Analyses

OBJECTIVES

We present a systematic review on the effectiveness of noninvasive respiratory support techniques in bronchiolitis.

DATA SOURCES

Systematic review with pairwise meta-analyses of all studies and network meta-analyses of the clinical trials.

STUDY SELECTION

Patients below 24 months old with bronchiolitis who require noninvasive respiratory support were included in randomized controlled trials (RCTs), non-RCT, and cohort studies in which high-flow nasal cannula (HFNC) was compared with conventional low-flow oxygen therapy (LFOT) and/or noninvasive ventilation (NIV).

DATA EXTRACTION

Emergency wards and hospitalized patients with bronchiolitis.

DATA SYNTHESIS

A total of 3,367 patients were analyzed in 14 RCTs and 8,385 patients in 14 non-RCTs studies. Only in nonexperimental studies, HFNC is associated with a lower risk of invasive mechanical ventilation (MV) than NIV (odds ratio, 0.49; 95% CI, 0.42-0.58), with no differences in experimental studies. There were no differences between HFNC and NIV in other outcomes. HFNC is more effective than LFOT in reducing oxygen days and treatment failure. In the network meta-analyses of clinical trials, NIV was the most effective intervention to avoid invasive MV (surface under the cumulative ranking curve [SUCRA], 57.03%) and to reduce days under oxygen therapy (SUCRA, 79.42%), although crossover effect estimates between interventions showed no significant differences. The included studies show methodological heterogeneity, but it is only statistically significant for the reduction of days of oxygen therapy and length of hospital stay.

CONCLUSIONS

Experimental evidence does not suggest that high-flow oxygen therapy has advantages over LFOT as initial treatment nor over NIV as a rescue treatment.

Clinical practice guidelines: management of severe bronchiolitis in infants under 12 months old admitted to a pediatric critical care unit

PURPOSE

We present guidelines for the management of infants under 12 months of age with severe bronchiolitis with the aim of creating a series of pragmatic recommendations for a patient subgroup that is poorly individualized in national and international guidelines.

METHODS

Twenty-five French-speaking experts, all members of the Groupe Francophone de Réanimation et Urgence Pédiatriques (French-speaking group of paediatric intensive and emergency care; GFRUP) (Algeria, Belgium, Canada, France, Switzerland), collaborated from 2021 to 2022 through teleconferences and face-to-face meetings. The guidelines cover five areas: (1) criteria for admission to a pediatric critical care unit, (2) environment and monitoring, (3) feeding and hydration, (4) ventilatory support and (5) adjuvant therapies. The questions were written in the Patient-Intervention-Comparison-Outcome (PICO) format. An extensive Anglophone and Francophone literature search indexed in the MEDLINE database via PubMed, Web of Science, Cochrane and Embase was performed using pre-established keywords. The texts were analyzed and classified according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. When this method did not apply, an expert opinion was given. Each of these recommendations was voted on by all the experts according to the Delphi methodology.

RESULTS

This group proposes 40 recommendations. The GRADE methodology could be applied for 17 of them (3 strong, 14 conditional) and an expert opinion was given for the remaining 23. All received strong approval during the first round of voting.

CONCLUSION

These guidelines cover the different aspects in the management of severe bronchiolitis in infants admitted to pediatric critical care units. Compared to the different ways to manage patients with severe bronchiolitis described in the literature, our original work proposes an overall less invasive approach in terms of monitoring and treatment.

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.

Commentary on High-Flow Nasal Cannula and Continuous Positive Airway Pressure Practices After the First-Line Support for Assistance in Breathing in Children Trials

Continuous positive airway pressure (CPAP) and heated humidified high-flow nasal cannula (HFNC) are commonly used to treat children admitted to the PICU who require more respiratory support than simple oxygen therapy. Much has been published on these two treatment modalities over the past decade, both in Pediatric Critical Care Medicine (PCCM ) and elsewhere. The majority of these studies are observational analyses of clinical, administrative, or quality improvement datasets and, therefore, are only able to establish associations between exposure to treatment and outcomes, not causation. None of the initial randomized clinical trials comparing HFNC and CPAP were definitive due to their relatively small sample sizes with insufficient power for meaningful clinical outcomes (e.g., escalation to bilevel noninvasive ventilation or intubation, duration of PICU-level respiratory support, mortality) and often yielded ambiguous findings or conflicting results. The recent publication of the First-Line Support for Assistance in Breathing in Children (FIRST-ABC) trials represented a major step toward understanding the role of CPAP and HFNC use in critically ill children. These large, pragmatic, randomized clinical trials examined the efficacy of CPAP and HFNC either for "step up" (i.e., escalation in respiratory support) during acute respiratory deterioration or for "step down" (i.e., postextubation need for respiratory support) management. This narrative review examines the body of evidence on HFNC published in PCCM , contextualizes the findings of randomized clinical trials of CPAP and HFNC up to and including the FIRST-ABC trials, provides guidance to PICU clinicians on how to implement the literature in current practice, and discusses remaining knowledge gaps and future research priorities.

Efficacy and Safety of Two Different Flow Rates of Nasal High-Flow Therapy in Preterm Neonates ≥28 Weeks of Gestation: A Randomized Controlled Trial

OBJECTIVE

The study aimed to compare the efficacy and safety of two different nasal high-flow rates for primary respiratory support in preterm neonates STUDY DESIGN:  In this single-center, double-blinded randomized controlled trial, preterm neonates ≥28 weeks of gestation with respiratory distress from birth were randomized to treatment with either increased nasal flow therapy (8-10 L/min) or standard nasal flow therapy (5-7 L/min). The primary outcome of nasal high-flow therapy failure was a composite outcome defined as the need for higher respiratory support (continuous positive airway pressure [CPAP] or mechanical ventilation) or surfactant therapy.

RESULTS

A total of 212 neonates were enrolled. Nasal high-flow failure rate in the increased flow group was similar to the standard flow group (22 vs. 29%, relative risk = 0.81 [95% confidence interval: 0.57-1.15]). However, nasal flow rate escalation was significantly more common in the standard flow group (64 vs. 43%, p = 0.004). None of the infants in the increased flow group developed air leak syndromes.

CONCLUSION

Higher nasal flow rate (8-10 L/min) when compared with lower nasal flow rate of 5 to 7 L/min did not reduce the need for higher respiratory support (CPAP/mechanical ventilation) or surfactant therapy in moderately and late preterm neonates. However, initial flow rates of 5 L/min were not optimal for most preterm infants receiving primary nasal flow therapy.

KEY POINTS

· Use of high nasal flows (8-10 L/min) did not reduce the need for higher respiratory support in moderately and late preterm infants.. · Nasal flow rate of 5 L/min was not optimal for most preterms with respiratory distress from birth.. · Careful patient selection and optimized flow settings could enhance nasal flow success in neonates..

Bronchiolitis

Viral bronchiolitis is the most common cause of admission to hospital for infants in high-income countries. Respiratory syncytial virus accounts for 60-80% of bronchiolitis presentations. Bronchiolitis is diagnosed clinically without the need for viral testing. Management recommendations, based predominantly on high-quality evidence, advise clinicians to support hydration and oxygenation only. Evidence suggests no benefit with use of glucocorticoids or bronchodilators, with further evidence required to support use of hypertonic saline in bronchiolitis. Evidence is scarce in the intensive care unit. Evidence suggests use of high-flow therapy in bronchiolitis is limited to rescue therapy after failure of standard subnasal oxygen only in infants who are hypoxic and does not decrease rates of intensive care unit admission or intubation. Despite systematic reviews and international clinical practice guidelines promoting supportive rather than interventional therapy, universal de-implementation of interventional care in bronchiolitis has not occurred and remains a major challenge.

High-Flow Nasal Cannula Oxygen Therapy: Physiological Mechanisms and Clinical Applications in Children

High-flow nasal cannula (HFNC) oxygen therapy has rapidly become a popular modality of respiratory support in pediatric care. This is undoubtedly due to its ease of use and safety, which allows it to be used in a wide variety of settings, ranging from pediatric intensive care to patients' homes. HFNC devices make it possible to regulate gas flow and temperature, as well as allowing some nebulized drugs to be administered, features very useful in children, in which the balance between therapeutic effectiveness and adherence to treatment is pivotal. Although the physiological effects of HFNC are still under investigation, their mechanisms of action include delivery of fixed concentration of oxygen, generation of positive end-expiratory pressure, reduction of the work of breathing and clearance of the nasopharyngeal dead space, while providing optimal gas conditioning. Nevertheless, current evidence supports the use of HFNC mainly in moderate-to-severe bronchiolitis, whereas for asthma exacerbations and breath sleeping disorders there is a lack of randomized controlled trials comparing HFNC to continuous positive airway pressure (CPAP) and non-invasive ventilation (NIV), which are essentials for the identification of response and non-response predictors. In this regard, the development of clinical guidelines for HFNC, including flow settings, indications, and contraindications is urgently needed.

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.

Changes in Ventilation Practices for Bronchiolitis in the Hospital Ward and Need for ICU Transfer over the Last Decade

There is limited evidence of the potential benefits of the use of high-flow nasal cannula (HFNC) for the management of bronchiolitis in the ward. Our aim is to describe the ventilation trends for bronchiolitis in our hospital along with the introduction of an HFNC ward protocol and to determine the need for respiratory support escalation and transfer to an intensive care unit (ICU). A retrospective analytical observational study of children < 12 months old requiring admission for a first RSV bronchiolitis episode in a single centre from January 2009 to December 2018. The sample was divided into four groups according to the type of respiratory support that would ensure the clinical stability of the infants on admission. A total of 502 infants were recruited. The total number and percentage of patients admitted in the ward grew progressively over time. Simultaneously, there was an increase in HFNC and, paradoxically, an increase in ICU transfers. The risk of failure was higher for those who required HFNC or CPAP for clinical stabilisation in the first 12 h after admission. Moreover, the risk of failure was also higher in children with standard oxygen therapy promptly escalated to HFNC, especially if they had atelectasis/viral pneumonia, coinfections or a history of prematurity. Despite the limitations of a retrospective analysis, our study reflects usual clinical practice and no correlation was found between the usage of HFNC and a shorter length of hospital stay or less time spent on oxygen therapy.

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).

Hospital Charges Associated With Critical Bronchiolitis From 2009 to 2019

OBJECTIVES

To evaluate the contribution of PICU care to increasing hospital charges for patients with bronchiolitis over a 10-year study period.

DESIGN

In this retrospective multicenter study, changes in annual hospital charges (adjusted for inflation) were analyzed using linear regression for subjects admitted to the PICU with invasive mechanical ventilation (PICU + IMV) and without IMV (PICU - IMV), and for children not requiring PICU care.

SETTING

Free-standing children's hospitals contributing to the Pediatric Health Information System (PHIS) database.

SUBJECTS

Children less than 2 years with bronchiolitis discharged from a PHIS hospital between July 2009 and June 2019. Subjects were categorized as high risk if they were born prematurely or had a chronic complex condition.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

PICU patients were 26.5% of the 283,006 included subjects but accrued 66% of the total $14.83 billion in charges. Annual charges increased from $1.01 billion in 2009-2010 to $2.07 billion in 2018-2019, and PICU patients accounted for 83% of this increase. PICU + IMV patients were 22% of all PICU patients and accrued 64% of all PICU charges, but PICU - IMV patients without a high-risk condition had the highest relative increase in annual charges, increasing from $76.7 million in 2009-2010 to $377.9 million in 2018-2019 (374% increase, ptrend < 0.001).

CONCLUSIONS

In a multicenter cohort study of children hospitalized with bronchiolitis, PICU patients, especially low-risk children without the need for IMV, were the highest driver of increased hospital charges over a 10-year study period.

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.

Analysis of risk factors for the failure of respiratory support with high-flow nasal cannula oxygen therapy in children with acute respiratory dysfunction: A case-control study

BACKGROUND

Evidence-based clinical practice guidelines regarding high-flow nasal cannula (HFNC) use for respiratory support in critically ill children are lacking. Therefore, we aimed to determine the risk factors for early HFNC failure to reduce the failure rate and prevent adverse consequences of HFNC failure in children with acute respiratory dysfunction.

METHODS

Demographic and laboratory data were compared among patients, admitted to the pediatric intensive care unit between January 2017 and December 2018, who were included in a retrospective cohort study. Univariate and multivariate analyses were performed to determine risk factors for eventual entry into the predictive model for early HFNC failure and to perform an external validation study in a prospective observational cohort study from January to February 2019. Further, the association of clinical indices and trends pre- and post-treatment with HFNC treatment success or failure in these patients was dynamically observed.

RESULTS

In total, 348 pediatric patients were included, of these 282 (81.0%) were included in the retrospective cohort study; HFNC success was observed in 182 patients (64.5%), HFNC 0-24 h failure in 74 patients (26.2%), and HFNC 24-48 h failure in 26 patients (9.2%). HFNC 24 h failure was significantly associated with the pediatric risk of mortality (PRISM) III score [odds ratio, 1.391; 95% confidence interval (CI): 1.249-1.550], arterial partial pressure of carbon dioxide-to-arterial partial pressure of oxygen (PaCO₂/PaO₂) ratio (odds ratio, 38.397; 95% CI: 6.410-230.013), and respiratory rate-oxygenation (ROX) index (odds ratio, 0.751; 95% CI: 0.616-0.915). The discriminating cutoff point for the new scoring system based on the three risk factors for HFNC 24 h failure was ≥ 2.0 points, with an area under the receiver operating characteristic curve of 0.794 (95% CI, 0.729-0.859, P < 0.001), sensitivity of 68%, and specificity of 79%; similar values were noted on applying the model to the prospective observational cohort comprising 66 patients (AUC = 0.717, 95% CI, 0.675-0.758, sensitivity 83%, specificity 44%, P = 0.009). In this prospective cohort, 11 patients with HFNC failure had an upward trend in PaCO₂/PaO₂ ratio and downward trends in respiratory failure index (P/F ratio) and ROX index; however, opposite directions of change were observed in 55 patients with HFNC success. Furthermore, the fractional changes (FCs) in PaCO₂/PaO₂ ratio, P/F ratio, percutaneous oxygen saturation-to-fraction of inspired oxygen (S/F) ratio, and ROX index at 2 h post-HFNC therapy onset were statistically significant between the two groups (all, P < 0.05).

CONCLUSION

In the pediatric patients with acute respiratory insufficiency, pre-treatment PRISM III score, PaCO₂/PaO₂ ratio, and ROX index were risk factors for HFNC 24 h failure, and the direction and magnitude of changes in the PaCO₂/PaO₂ ratio, P/F ratio, and ROX index before and 2 h after HFNC treatment were warning indicators for HFNC 24 h failure. Further close monitoring should be considered for patients with these conditions.

Clinical review of High Flow Nasal Cannula and Continuous Positive Airway Pressure in pediatric acute respiratory distress

Acute Respiratory Distress Syndrome (ARDS) causes much morbidity and mortality in children. In mild to moderate ARDS, non-invasive ventilation (NIV) is the treatment of choice. Recently, there are 2 kinds of NIV used Continuous Positive Airway Pressure (CPAP) or High Flow Nasal Cannula (HFNC). Both of them can be used in various respiratory distress and have different physiological mechanisms. The effectiveness to improve the clinical parameter, morbidity, and mortality are similar between CPAP and HFNC. However, HFNC application is more tolerated in acute respiratory distress in children, with less nasal injury, lower heart rate inflicted, and better comfort index score.

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CPAP & HFNC widely used in pediatric acute respiratory distress.

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Both modalities have a different characteristics, beneficial in certain condition.

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The usage of each modalities depends on the causes of the respiratory distress.

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

Asthma is the commonest obstructive airway disease and the leading cause of morbidity in children. In the pediatric population, acute exacerbations of asthma are a frequent cause of presentations and hospital admissions. An acute asthma exacerbation is potentially life-threatening; it is predominantly treated using conventional oxygen therapy with bronchodilators and systemic corticosteroids. The treatment of those who do not respond to conventional therapy is escalated to noninvasive positive pressure ventilation (NIPPV) before invasive ventilation. Although NIPPV has demonstrated benefits and safety, it still has limitations such as treatment intolerance caused mainly by discomfort and complications. High-flow oxygen therapy administered through a nasal cannula (HFNC) provides respiratory support with adequate airway humidity and has demonstrated safety and benefits in clinical practice. In the present review, we discuss HFNC and variations in HFNC use, focusing on its feasibility and current evidence of using it on children with asthma exacerbations.

Predicting Flow Rate Escalation for Pediatric Patients on High Flow Nasal Cannula Using Machine Learning

Background: High flow nasal cannula (HFNC) is commonly used as non-invasive respiratory support in critically ill children. There are limited data to inform consensus on optimal device parameters, determinants of successful patient response, and indications for escalation of support. Clinical scores, such as the respiratory rate-oxygenation (ROX) index, have been described as a means to predict HFNC non-response, but are limited to evaluating for escalations to invasive mechanical ventilation (MV). In the presence of apparent HFNC non-response, a clinician may choose to increase the HFNC flow rate to hypothetically prevent further respiratory deterioration, transition to an alternative non-invasive interface, or intubation for MV. To date, no models have been assessed to predict subsequent escalations of HFNC flow rates after HFNC initiation. Objective: To evaluate the abilities of tree-based machine learning algorithms to predict HFNC flow rate escalations. Methods: We performed a retrospective, cohort study assessing children admitted for acute respiratory failure under 24 months of age placed on HFNC in the Johns Hopkins Children's Center pediatric intensive care unit from January 2019 through January 2020. We excluded encounters with gaps in recorded clinical data, encounters in which MV treatment occurred prior to HFNC, and cases electively intubated in the operating room. The primary study outcome was discriminatory capacity of generated machine learning algorithms to predict HFNC flow rate escalations as compared to each other and ROX indices using area under the receiver operating characteristic (AUROC) analyses. In an exploratory fashion, model feature importance rankings were assessed by comparing Shapley values. Results: Our gradient boosting model with a time window of 8 h and lead time of 1 h before HFNC flow rate escalation achieved an AUROC with a 95% confidence interval of 0.810 ± 0.003. In comparison, the ROX index achieved an AUROC of 0.525 ± 0.000. Conclusion: In this single-center, retrospective cohort study assessing children under 24 months of age receiving HFNC for acute respiratory failure, tree-based machine learning models outperformed the ROX index in predicting subsequent flow rate escalations. Further validation studies are needed to ensure generalizability for bedside application.

Clinico-virological Profile, Intensive Care Needs, and Outcome of Infants with Acute Viral Bronchiolitis: A Prospective Observational Study

OBJECTIVES

The objective of the study was to describe the clinico-virological profile, treatment details, intensive care needs, and outcome of infants with acute viral bronchiolitis (AVB).

METHODOLOGY

In this prospective observational study, 173 infants with AVB admitted to the pediatric emergency room and pediatric intensive care unit (PICU) of a tertiary care teaching hospital in North India during November 2019 to February 2020 were enrolled. The data collection included clinical features, viruses detected [respiratory syncytial virus (RSV), rhinovirus, influenza A virus, parainfluenza virus (PIV) 2 and 3, and human metapneumovirus (hMPV)], complications, intensive care needs, treatment, and outcomes. Multivariate analysis was performed to determine independent predictors for PICU admission.

RESULTS

Most common symptoms were rapid breathing (98.8%), cough (98.3%), and fever (74%). On examination, tachypnea (98.8%), chest retractions (93.6%), respiratory failure (84.4%), wheezing (49.7%), and crepitations (23.1%) were observed. RSV and rhinovirus were the predominant isolates. Complications were noted in 25% of cases as encephalopathy (17.3%), transaminitis (14.3%), shock (13.9%), acute kidney injury (AKI) (7.5%), myocarditis (6.4%), multiple organ dysfunction syndrome (MODS) (5.8%), and acute respiratory distress syndrome (ARDS) (4.6%). More than one-third of cases required PICU admission. The treatment details included nasal cannula oxygen (11%), continuous positive airway pressure (51.4%), high-flow nasal cannula (14.5%), mechanical ventilation (23.1%), nebulization (74%), antibiotics (35.9%), and vasoactive drugs (13.9%). The mortality was 8.1%. Underlying comorbidity, chest retractions, respiratory failure at admission, presence of shock, and need for mechanical ventilation were independent predictors of PICU admission. Isolation of virus or coinfection was not associated with disease severity, intensive care needs, and outcomes.

CONCLUSION

Among infants with AVB, RSV and rhinovirus were predominant. One-third infants with AVB needed PICU admission. The presence of comorbidity, chest retractions, respiratory failure, shock, and need for mechanical ventilation independently predicted PICU admission.

HOW TO CITE THIS ARTICLE

Angurana SK, Takia L, Sarkar S, Jangra I, Bora I, Ratho RK, et al. Clinico-virological Profile, Intensive Care Needs, and Outcome of Infants with Acute Viral Bronchiolitis: A Prospective Observational Study. Indian J Crit Care Med 2021;25(11):1301-1307.

Velocity-based target flow rate for high-flow nasal cannula oxygen therapy

BACKGROUND

The aim of this study was to assess retrospectively whether the average inspiratory flow velocity-based initial flow rate in high-flow nasal cannula (HFNC) therapy could be well tolerated and safely used for infants and children hospitalized with moderate to severe respiratory failure.

METHODS

Thirty-three patients without underlying diseases (22 males; 67%), hospitalized to receive HFNC therapy for infection-related respiratory failure, were analyzed. The median age was 2 months (interquartile range, 1 month to 1 year). Patients with dyspnea and carbon dioxide partial pressure (pCO₂ ) >50 mmHg or venous blood pH <7.320, combined with pulse oximetry arterial oxygen saturation <92%, were included. We set target flow rates calculated from the average inspiratory flow velocity, starting at the actual initial flow rates, and these were subsequently adjusted if necessary.

RESULTS

One patient could not tolerate the cannula. Of the remaining 32 patients, 81% (n = 26) had an actual initial flow rate within 1 L of the target flow rate; these patients were evaluated for changes in the fraction of inspired oxygen (FITarget flow rate tableO₂ ), pH, and pCO₂ values after 24 h. Three patients required a higher fraction of inspired oxygen, one showed a persistent pH < 7.320, and seven exhibited pCO₂ >50 mmHg. No patient required non-invasive positive-pressure ventilation, and one required intubation. Pneumothorax was not reported in any patient.

CONCLUSIONS

The average inspiratory flow velocity-based initial flow rate was well-tolerated without sedation, and there were no severe complications. Starting at this flow rate would improve the use of HFNC therapy in the pediatric ward, possibly reducing the need for more invasive modes of ventilation.

Efficacy and safety of high flow nasal oxygen for children with bronchiolitis: systematic review and meta-analysis

BACKGROUND

To assess the published evidence to establish the efficacy and safety of high flow oxygen cannula (HFNC) as respiratory support for children up to 24 months of age with bronchiolitis within acute hospital settings.

METHODS

We searched eight databases up to March 2021. Studies including children up to 24 months of age with a diagnosis of bronchiolitis recruited to an randomised controlled trial were considered in the full meta-analysis. At least one arm of the study must include HFNC as respiratory support and report at least one of the outcomes of interest. Studies were identified and extracted by two reviewers. Data were analysed using Review Manager V.5.4.

RESULTS

From 2943 article titles, 308 full articles were screened for inclusion. 23 studies met the inclusion criteria, 15 were included in the metanalyses. Four studies reported on treatment failure rates when comparing HFNC to standard oxygen therapy (SOT). Data suggests HFNC is superior to SOT (OR 0.45, 95% CI 0.36 to 0.57). Four studies reported on treatment failure rates when comparing HFNC to continuous positive airways pressure (CPAP). No significant difference was found between CPAP and HFNC (OR 1.64, 95% CI 0.96 to 2.79; p=0.07). Four studies report on adverse outcomes when comparing HFNC to SOT. No significant difference was found between HFNC & SOT (OR 1.47, 95% CI 0.54 to 3.99).

CONCLUSION

HFNC is superior to SOT in terms of treatment failure and there is no significant difference between HFNC and CPAP in terms of treatment failure. The results suggest HFNC is safe to use in acute hospital settings.

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.

Variability in care for children with severe acute asthma in Latin America

BACKGROUND

Care variability for children with severe acute asthma has been well documented in high-income countries, yet data from low- and middle-income regions are lacking. We sought to characterize the magnitude of practice variability in the care of Latin American children to identify opportunities for standardization of care.

METHODS

A cross-sectional study performed through a retrospective analysis of contemporaneously collected data of children with severe acute asthma admitted to a center contributing to the LARed Network registry between May 2017 and May 2019. Centers were grouped by geographic location: Atlantic (AT), South Pacific (SP), and North Central (NC).

RESULTS

Among 434 children, most received care in hospitals in the AT group (54% [235/434]), followed by the NC (23% [101/434]) and SP (23% [98/434]) groups. The majority of children in the AT (92% [215/235]) and SP (91% [89/98]) groups received nebulized salbutamol/albuterol, while metered-dose inhalers were preferred in the NC group (72% [73/101]). There was a wide variation in the use of antibiotics: AT (57% [135/235]), SP (48% [47/98]), and NC (14% [14/101]). The same was true for ipratropium bromide: AT (67% [157/235]), SP (90% [88/98]), and NC (17% [17/101]), and aminophylline: AT (57% [135/235]), NC (5% [5/101]), and SP (0% [0/98]). High-flow nasal cannula was the preferred respiratory support modality in the AT (60% [141/235]) and NC (40% [40/101]) groups, while bilevel positive airway pressure (BiPAP) use was more common in the SP group (80% [78/98]).

CONCLUSION

We identified significant variability in care for severe acute asthma. Our findings will help to inform the design of future studies, quality improvement initiatives, and development of practice guidelines within Latin America.

Update on the Role of High-Flow Nasal Cannula in Infants with Bronchiolitis

Bronchiolitis (BR), a lower respiratory tract infection mainly caused by respiratory syncytial virus (RSV), can be very severe. Presently, adequate nutritional support and oxygen therapy remain the only interventions recommended to treat patients with BR. For years, mild BR cases were treated with noninvasive standard oxygen therapy (SOT), i.e., with cold and poorly or totally non-humidified oxygen delivered by an ambient headbox or low-flow nasal cannula. Children with severe disease were intubated and treated with invasive mechanical ventilation (IMV). To improve SOT and overcome the disadvantages of IMV, new measures of noninvasive and more efficient oxygen administration have been studied. Bi-level positive air way pressure (BiPAP), continuous positive airway pressure (CPAP), and high-flow nasal cannula (HFNC) are among them. For its simplicity, good tolerability and safety, and the good results reported in clinical studies, HFNC has become increasingly popular and is now widely used. However, consistent guidelines for initiation and discontinuation of HFNC are lacking. In this narrative review, the role of HFNC to treat infants with BR is discussed. An analysis of the literature showed that, despite its widespread use, the role of HFNC in preventing respiratory failure in children with BR is not precisely defined. It is not established whether it can offer greater benefits compared to SOT and when and in which infants it can replace CPAP or BiPAP. The analysis of the results clearly indicates the need for multicenter studies and official guidelines. In the meantime, HFNC can be considered a safe and effective method to treat children with mild to moderate BR who do not respond to SOT.

Real-life study of the role of high-flow nasal cannula for bronchiolitis in children younger than 3 months hospitalised in general pediatric departments

We aimed to describe the real-life role of high-flow nasal cannula (HFNC) for bronchiolitis in infants under 3 months of age admitted to three general pediatric departments during the 2017-2018 epidemic period. We retrospectively assessed the clinical severity (Wang score) for every 24-h period of treatment (H0-H24 and H24-H48) according to the initiated medical care (HFNC, oxygen via nasal cannula, or supportive treatments only), the child's discomfort (EDIN score), and transfer to the pediatric intensive care unit (PICU). A total of 138 infants were included: 47±53 days old, 4661±851.9 g, 70 boys (50.7%), 58 with hypoxemia (42%), Wang score of 6.67±2.58, 110 (79.7%) staying for 48 consecutive hours in the same ward. During the H0-H24 period, only patients treated with HFNC had a statistically significant decrease in the severity score (n=21/110; -2 points, P=0.002) and an improvement in the discomfort score (n=15/63; -3.8 points, P<0.0001). There was no difference between groups during the H24-H48 period. The rate of admission to the PICU was 2.9% for patients treated for at least 24 h with HFNC (n=34/138, 44% with oxygen) versus 16.3% for the others (P=0.033). Early use of HFNC improves both clinical status and discomfort in infants younger than 3 months admitted for moderately severe bronchiolitis, whatever their oxygen status.

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.

Has the introduction of high-flow nasal cannula modified the clinical characteristics and outcomes of infants with bronchiolitis admitted to pediatric intensive care units? A retrospective study

BACKGROUND

This study aimed to assess how the emergence of high-flow nasal cannula (HFNC) has modified the demographic and clinical characteristics as well as outcomes of infants with bronchiolitis admitted to a pediatric intensive care unit (PICU).

METHODS

This was a single-center retrospective study including infants aged 1 day to 6 months with bronchiolitis requiring HFNC, noninvasive ventilation (NIV), or invasive ventilation on admission.

RESULTS

A total of 252 infants (mean age 53±36 days) were included in the study. The use of HFNC increased from 18 (21.4%) during 2013-2014 to 53 infants (55.2%) during 2015-2016. The length of stay in the PICU decreased over time from 4.7±2.9 to 3.5±2.7 days (P<0.01) but the hospital length of stay remained similar (P=0.17). On admission, patients supported by HFNC as the first-line therapy were older. The PICU length of stay was similar according to the type of respiratory support (P=0.16), but the hospital length of stay was longer for patients supported by HFNC (P=0.01).

CONCLUSION

The distribution of respiratory support has significantly changed over time for patients with bronchiolitis and HFNC is increasingly used. The demographic and clinical characteristics of the have not changed over time. However, the PICU length of stay decreased significantly.

Nasal high flow higher than 60 L/min in patients with acute hypoxemic respiratory failure: a physiological study

Background

Nasal high flow delivered at flow rates higher than 60 L/min in patients with acute hypoxemic respiratory failure might be associated with improved physiological effects. However, poor comfort might limit feasibility of its clinical use.

Methods

We performed a prospective randomized cross-over physiological study on 12 ICU patients with acute hypoxemic respiratory failure. Patients underwent three steps at the following gas flow: 0.5 L/kg PBW/min, 1 L/kg PBW/min, and 1.5 L/kg PBW/min in random order for 20 min. Temperature and FiO₂ remained unchanged. Toward the end of each phase, we collected arterial blood gases, lung volumes, and regional distribution of ventilation assessed by electrical impedance tomography (EIT), and comfort.

Results

In five patients, the etiology was pulmonary; infective disease characterized seven patients; median PaO₂/FiO₂ at enrollment was 213 [IQR 136–232]. The range of flow rate during NHF 1.5 was 75–120 L/min. PaO₂/FiO₂ increased with flow, albeit non significantly (p = 0.064), PaCO₂ and arterial pH remained stable (p = 0.108 and p = 0.105). Respiratory rate decreased at higher flow rates (p = 0.014). Inhomogeneity of ventilation decreased significantly at higher flows (p = 0.004) and lung volume at end-expiration significantly increased (p = 0.007), but mostly in the non-dependent regions. Comfort was significantly poorer during the step performed at the highest flow (p < 0.001).

Conclusions

NHF delivered at rates higher than 60 L/min in critically ill patients with acute hypoxemic respiratory failure is associated with reduced respiratory rate, increased lung homogeneity, and additional positive pressure effect, but also with worse comfort.

Acute Viral Bronchiolitis: A Narrative Review

Acute viral bronchiolitis (AVB) is the leading cause of hospital admissions among infants in developed and developing countries and associated with increased morbidity and cost of treatment. This review was performed to guide the clinicians managing AVB in light of evidence accumulated in the last decade. We searched published English literature in last decade regarding etiology, diagnosis, treatment, and prevention of AVB using PubMed and Cochrane Database of Systematic Reviews. Respiratory syncytial virus is the most common causative agent. The diagnosis is mainly clinical with limited role of diagnostic investigations and chest radiographs are not routinely indicated. The management of AVB remains a challenge, as the role of various interventions is not clear. Supportive care in from of provision of heated and humidified oxygen and maintaining hydration are main interventions. The use of pulse oximetry helps to guide the administration of oxygen. Trials and systematic reviews evaluated various interventions like nebulized adrenaline, bronchodilators and hypertonic saline, corticosteroids, different modes of noninvasive ventilation (high-flow nasal cannula [HFNC], continuous positive airway pressure [CPAP], and noninvasive positive pressure ventilation [NPPV]), surfactant, heliox, chest physiotherapy, and antiviral drugs. The interventions which showed some benefits in infants and children with AVB are adrenaline and hypertonic saline nebulization, HFNC, CPAP, NIV, and surfactant. The routine administration of antibiotics, bronchodilators, corticosteroids, steam inhalation, chest physiotherapy, heliox, and antiviral drugs are not recommended.

A randomised trial of high-flow nasal cannula in infants with moderate bronchiolitis

BACKGROUND

The objective was to determine whether high-flow nasal cannula (HFNC), a promising respiratory support in infant bronchiolitis, could reduce the proportion of treatment failure requiring escalation of care.

METHODS

In this randomised controlled trial, we assigned infants aged <6 months who had moderate bronchiolitis to receive either HFNC at 3 L·kg^-1·min^-1 or standard oxygen therapy. Crossover was not allowed. The primary outcome was the proportion of patients in treatment failure requiring escalation of care (mostly noninvasive ventilation) within 7 days following randomisation. Secondary outcomes included rates of transfer to the paediatric intensive care unit (PICU), oxygen, number of artificial nutritional support-free days and adverse events.

RESULTS

The analyses included 268 patients among the 2621 infants assessed for inclusion during two consecutive seasons in 17 French paediatric emergency departments. The percentage of infants in treatment failure was 14% (19 out of 133) in the study group, compared to 20% (27 out of 135) in the control group (OR 0.66, 95% CI 0.35-1.26; p=0.21). HFNC did not reduce the risk of admission to PICU (21 (15%) out of 133 in the study group versus 26 (19%) out of 135 in the control group) (OR 0.78, 95% CI 0.41-1.41; p=0.45). The main reason for treatment failure was the worsening of modified Wood clinical asthma score (m-WCAS). Short-term assessment of respiratory status showed a significant difference for m-WCAS and respiratory rate in favour of HFNC. Three pneumothoraces were reported in the study group.

CONCLUSIONS

In patients with moderate bronchiolitis, there was no evidence of lower rate of escalating respiratory support among those receiving HFNC therapy.

Apnoeic oxygenation in paediatric anaesthesia: a narrative review

Apnoeic oxygenation refers to oxygenation in the absence of any patient or ventilator effort to move the lungs. This phenomenon was first described in humans in the mid-20th century but has seen renewed interest in the last decade following the demonstration of apnoeic oxygenation with low-flow, and subsequently high-flow, nasal oxygen. This narrative review summarises our understanding of apnoeic oxygenation in the paediatric population. We examine the evidence supporting oxygenation via tracheal tube, modified laryngoscopes and nasal cannulae. The evidence for prolongation of safe apnoea time at induction of anaesthesia is also appraised. We explore the capacity for carbon dioxide clearance, flow rate selection with high-flow nasal oxygen and complications associated with the technique. It remains uncertain whether apnoeic oxygenation in paediatric patients results in a meaningful clinical benefit compared with standard care for outcomes such as the number of tracheal intubation attempts or the incidence of hypoxaemia. In particular, the role of apnoeic oxygenation in paediatric difficult airway management is unclear as this has not been the targeted focus of any published research to date.

High flow nasal cannula as respiratory support in treating infant bronchiolitis: a systematic review

Bronchiolitis is a common respiratory illness in early childhood, often leading to hospitalization and associated healthcare costs. Low flow 100% oxygen through nasal prongs is the standard therapy for infants with bronchiolitis and hypoxemia. Nasal continuous positive airway pressure (nCPAP) or invasive ventilation is used in case of progressive respiratory failure. High flow heated and humidified oxygen therapy with delivery of an air-oxygen mixture up to 2 L/min/kg body weight via nasal prongs (referred to as high flow nasal cannula or HFNC) is a newer method for respiratory support. Initial data from retrospective studies were promising but should be interpreted with caution. A limited number of prospective randomized controlled trials (RCT) have now compared HFNC with either standard oxygen therapy (SOT) or nCPAP. In this review, we critically summarize the data from these RCTs with the aim to provide advice on how to position HFNC in clinical practice.Conclusion: HFNC is a safe mode of respiratory support that can be positioned between SOT and nCPAP as rescue therapy for children not adequately supported by SOT. It does not seem to shorten the duration of oxygen need nor the duration of hospital admission.What is Known:• HFNC is being used increasingly in the context of infant bronchiolitis. However, evidence on efficacy and safety are limited. Different published studies involve different disease severities and different pediatric settings.What is New:• In this review, we summarize data only from prospective RCTs with the aim to provide guidance on how to use HFNC.

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.