The effect of high flow nasal cannula therapy on the work of breathing in infants with bronchiolitis

High flow nasal cannula use outside of the ICU; factors associated with failure

OBJECTIVES

High flow nasal cannula (HFNC) use is increasing in pediatrics. Few studies exist examining the safety of HFNC use outside the intensive care unit (ICU). This study aimed to characterize patient qualities associated with failure of HFNC use outside the ICU.

STUDY DESIGN

A retrospective chart review of patients placed on HFNC outside the ICU from September 2011 to July 2013 was completed. Failure was defined as intubation or cardiopulmonary arrest. Two-sample tests and binary logistic regression determined significant factors associated with failed HFNC administration, both unadjusted and adjusted for hospital.

RESULTS

Two hundred thirty-one patients met inclusion criteria, with 192 receiving treatment for a primary respiratory diagnosis (83%). Fourteen (6%) progressed to HFNC failure; 12 transferred to the ICU and were intubated, two with congenital heart disease suffered cardiopulmonary arrest on the floor. Two-sample tests revealed failure patients were more likely to have a cardiac history (P = 0.026), history of intubation (P = 0.040), and require higher fraction of inspired oxygen (FiO₂ ) (median 100%; 25th-75th 60-100%; P = <0.001). Hospital adjusted logistic regression further demonstrated failure patients were more likely to be treated with higher FiO₂ (OR: 38.3; 95% CI: 4.0-366.3; P = 0.002), and less likely to have a diagnosis of bronchiolitis (OR: 0.3; 95% CI: 0.1-0.9; P = 0.048).

CONCLUSIONS

High FiO₂ requirements, history of intubation, and cardiac co-morbidity are associative predictors of HFNC failure. Bronchiolitis patients may be treated with HFNC outside of the ICU with lower odds of failure. Pediatr Pulmonol. 2017;52:806-812. © 2017 Wiley Periodicals, Inc.

Complex effects of high-flow nasal cannula therapy on hemodynamics in the pediatric patient after cardiac surgery

Background

The high-flow nasal cannula (HFNC) system has been widely used for children in various clinical settings. However, the physiological and clinical impact of HFNC therapy on the pediatric patient with respiratory distress after cardiac surgery has not been thoroughly investigated.

Main body of the abstract

It seems logical to use HFNC as a primary therapy for post-extubation respiratory failure after congenital heart surgery, in which low cardiac output syndrome and upper airway obstruction are commonly encountered; the HFNC therapy alleviates the work of breathing and large negative swings of intrathoracic pressure, which in turn helps to decrease the systemic ventricular afterload. When applying HFNC to patients after congenital heart surgery, however, consideration must be given to its diverse effects on hemodynamics because of the complex respiratory and cardiac pathophysiology in these patients. The positive pressure generated by HFNC can exert different effects on pulmonary vascular resistance depending on the lung condition, while its impact on cardiac output may also differ depending on the cardiac physiology. The hemodynamic effects of HFNC may become even more complex in a patient with a single ventricle. To better assess its physiologic effects in patients after cardiac surgery, future studies could utilize various modalities including esophageal balloon catheters, electrical impedance tomography, and near-infrared spectroscopy. At the same time, studies should focus on specific types of cardiac pathophysiology or surgery when evaluating the effects of HFNC, since it may exert various effects, depending on the cardiac physiology or preoperative pulmonary hemodynamics. Lastly, the optimal flow rate at which the benefit of HFNC is maximized through favorable cardiopulmonary interactions should be determined in future studies.

Short conclusion

Further studies are needed to better understand the effect of HFNC in different cardiac and respiratory physiologies, given their complexity in pediatric patients after cardiac surgery.

Comparison of CPAP and HFNC in Management of Bronchiolitis in Infants and Young Children

Continuous positive airway pressure (CPAP) has been used in infants with bronchiolitis for decades. Recently, high flow nasal cannula (HFNC) therapy was introduced We conducted a retrospective study of treatment with CPAP vs. HFNC between 2013 and 2015, comparing the development in respiratory rate, fraction of inspired oxygen (FiO2) and heart rate, treatment failure, duration of treatment, and length of hospital stay. A sample size of 49 children were included. Median age was 1.9 months. Median baseline pCO₂ was 7.4 kPa in both groups, respiratory rate per minute was 57 vs. 58 (CPAP vs. HFNC). Respiratory rate decreased faster in the CPAP group (p < 0.05). FiO2 decreased in the CPAP group and increased in the HFNC group during the first 12 h, whereafter it decreased in both groups. (p < 0.01). Heart rate development was similar in both groups. Twelve children (55%) changed systems from HFNC to CPAP due to disease progression. There was no difference in length of treatment, hospital stay, or transmission to intensive care unit between the groups. CPAP was more effective than HFNC in decreasing respiratory rate (RR) and FiO2. No differences were observed in length of treatment or complications. Further studies should be conducted to compare the efficacy of the two treatments of bronchiolitis, preferably through prospective randomized trials.

Hyponatremia and Hypotonic Intravenous Fluids Are Associated With Unfavorable Outcomes of Bronchiolitis Admissions

OBJECTIVES

Hyponatremia has been associated with unfavorable outcomes when present at admission in children with bronchiolitis. Delayed hyponatremia may be a modifiable risk factor for severe disease that is influenced by intravenous fluid (IVF) tonicity. We hypothesized that both hyponatremia and prescription of severely hypotonic IVF are associated with unfavorable outcomes, and that prescription of severely hypotonic IVF is associated with subsequent hyponatremia.

METHODS

Data were retrospectively extracted for 1557 pediatric inpatients with bronchiolitis. Any day on which a subject was prescribed IVF with sodium <70 mEq/L was termed "IVF <70." All other days on which IVF was prescribed were termed "IVF ≥70." Any blood sodium ≤135 mEq/L defined hyponatremia for that day. All other days with sodium available were labeled normonatremia. Variables were compared with Spearman correlation, Wilcoxon rank test, or χ². Significant results had P < .05.

RESULTS

Blood sodium levels correlated negatively with hospital length of stay (r = -0.477, P < .0001). On each of the first 4 days of hospitalization, significantly increased hospital length of stay was observed in patients with hyponatremia (n = 134 [25.7% of subjects with available sodium data]) versus patients with normonatremia (n = 387 [74.3%]), and in patients prescribed IVF <70 (n = 348 [46.3% of subjects prescribed IVF]) versus patients prescribed IVF ≥70 (n = 403 [53.7%]). Patients prescribed IVF <70 had increased rates of hyponatremia on the subsequent day versus patients prescribed IVF ≥70 (50.0% vs 26.9%, P < .001).

CONCLUSIONS

In children hospitalized with bronchiolitis, hyponatremia may be a modifiable risk factor for severe disease that may be mitigated by avoiding use of severely hypotonic IVF.

Clinical Outcomes of Bronchiolitis After Implementation of a General Ward High Flow Nasal Cannula Guideline

OBJECTIVE

The goal of this study was to assess the association of the introduction of a ward's high-flow nasal cannula (HFNC) guideline with clinical outcomes of infants with bronchiolitis.

METHODS

We conducted a retrospective, pre-post intervention study with an interrupted time series analysis of infants admitted with bronchiolitis between 2010 and 2014 at an urban, tertiary care children's hospital. Patients admitted in the 24 months before and after initiation of a guideline for HFNC use on the general wards were compared. The primary outcome was length of hospital stay. Secondary outcomes were PICU transfer rate and length of stay, intubation rate, and 30-day readmission, adjusted for season.

RESULTS

A total of 1937 patients met inclusion criteria; 936 were admitted before and 1001 admitted after the introduction of HFNC use on the general wards. Comparing the 2 groups, the hospital-wide rate of HFNC use in bronchiolitis treatment increased after HFNC became available on the wards (23.9% vs 35.2%; P < .001). The ward's HFNC guideline was not associated with a change in preintervention trajectory of total hospital length of stay (P = .48), PICU length of stay (P = .06), or rate of PICU transfer (P = .97). There was also no difference in intubation rate or 30-day readmission between the 2 groups.

CONCLUSIONS

Initiating a guideline for HFNC use on the general pediatric wards was associated with an increase in the use of the intervention with no significant change in total hospital length of stay, PICU length of stay and transfer rate, intubation rate, or 30-day readmission for patients with bronchiolitis.

Management of acute respiratory diseases in the pediatric population: the role of oral corticosteroids

Respiratory diseases account for about 25% of all pediatric consultations, and 10% of these are for asthma. The other main pediatric respiratory diseases, in terms of incidence, are bronchiolitis, acute bronchitis and respiratory infections. Oral corticosteroids, in particular prednisolone, are often used to treat acute respiratory diseases given their anti-inflammatory effects. However, the efficacy of treatment with oral corticosteroids differs among the various types of pediatric respiratory diseases. Notably, also the adverse effects of corticosteroid treatment can differ depending on dosage, duration of treatment and type of corticosteroid administered — a case in point being growth retardation in long-course treatment. A large body of data has accumulated on this topic. In this article, we have reviewed the data and guidelines related to the role of oral corticosteroids in the treatment and management of pediatric bronchiolitis, wheezing, asthma and croup in the attempt to provide guidance for physicians. Also included is a section on the management of acute respiratory failure in children.

Recent Advances in Pediatric Ventilatory Assistance

In this review on respiratory assistance, we aim to discuss the following recent advances: the optimization and customization of mechanical ventilation, the use of high-frequency oscillatory ventilation, and the role of noninvasive ventilation. The prevention of ventilator-induced lung injury and diaphragmatic dysfunction is now a key aspect in the management of mechanical ventilation, since these complications may lead to higher mortality and prolonged length of stay in intensive care units. Different physiological measurements, such as esophageal pressure, electrical activity of the diaphragm, and volumetric capnography, may be useful objective tools to help guide ventilator assistance. Companies that design medical devices including ventilators and respiratory monitoring platforms play a key role in knowledge application. The creation of a ventilation consortium that includes companies, clinicians, researchers, and stakeholders could be a solution to promote much-needed device development and knowledge implementation.

The Clinical Impact of Heated Humidified High-Flow Nasal Cannula on Pediatric Respiratory Distress

OBJECTIVES

To assess the impact on a single PICU of introducing high-flow nasal cannula as a management tool for respiratory distress.

DESIGN

Retrospective cohort study, including an interrupted time series analysis with a propensity score adjustment and a matched-pair analysis.

SETTING

A single university-affiliated children's hospital PICU.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Differences in clinical outcomes when comparing the pre-high-flow nasal cannula era (2004-2008) and the high-flow nasal cannula era (2010-2014), excluding 2009 as a washout period, and clinical impacts of high-flow nasal cannula as an exposure of interest. A total of 1,766 children met the inclusion criteria (pre-high-flow nasal cannula era: 699 patients; high-flow nasal cannula era: 1,067 patients). High-flow nasal cannula was used in 455 patients (42.6%) in the high-flow nasal cannula era. The interrupted time series analysis failed to show a statistically significant difference in PICU length of stay, but the duration of invasive ventilation was shortened by an average of 2.3 days in the high-flow nasal cannula era group (95% CI, 0.2-4.4; p = 0.030). The PICU intubation rate in the high-flow nasal cannula era was 0.72 times that of the pre-high-flow nasal cannula era (95% CI, 0.63-0.84; p < 0.001). A total of 373 pairs were formed for the matched-pair analysis. The odds for being intubated in the PICU for those patients using high-flow nasal cannula was 0.06 (95% CI, 0.02-0.16; p < 0.001) when compared with those who did not use high-flow nasal cannula. The PICU length of stay increased by 2.9 days in those patients in which high-flow nasal cannula was used (95% CI, 1.3-4.4; p < 0.001).

CONCLUSIONS

The introduction of high-flow nasal cannula as a therapy for respiratory distress in the PICU was associated with a significant decrease in the PICU intubation rate with no associated change in mortality.

High flow nasal cannula (HFNC) versus nasal continuous positive airway pressure (nCPAP) for the initial respiratory management of acute viral bronchiolitis in young infants: a multicenter randomized controlled trial (TRAMONTANE study)

PURPOSE

Nasal continuous positive airway pressure (nCPAP) is currently the gold standard for respiratory support for moderate to severe acute viral bronchiolitis (AVB). Although oxygen delivery via high flow nasal cannula (HFNC) is increasingly used, evidence of its efficacy and safety is lacking in infants.

METHODS

A randomized controlled trial was performed in five pediatric intensive care units (PICUs) to compare 7 cmH₂O nCPAP with 2 L/kg/min oxygen therapy administered with HFNC in infants up to 6 months old with moderate to severe AVB. The primary endpoint was the percentage of failure within 24 h of randomization using prespecified criteria. To satisfy noninferiority, the failure rate of HFNC had to lie within 15% of the failure rate of nCPAP. Secondary outcomes included success rate after crossover, intubation rate, length of stay, and serious adverse events.

RESULTS

From November 2014 to March 2015, 142 infants were included and equally distributed into groups. The risk difference of -19% (95% CI -35 to -3%) did not allow the conclusion of HFNC noninferiority (p = 0.707). Superiority analysis suggested a relative risk of success 1.63 (95% CI 1.02-2.63) higher with nCPAP. The success rate with the alternative respiratory support, intubation rate, durations of noninvasive and invasive ventilation, skin lesions, and length of PICU stay were comparable between groups. No patient had air leak syndrome or died.

CONCLUSION

In young infants with moderate to severe AVB, initial management with HFNC did not have a failure rate similar to that of nCPAP. This clinical trial was recorded in the National Library of Medicine registry (NCT 02457013).

Non-invasive respiratory support for infants with bronchiolitis: a national survey of practice

Background

Bronchiolitis is a common respiratory illness of early childhood. For most children it is a mild self-limiting disease but a small number of children develop respiratory failure. Nasal continuous positive airway pressure (nCPAP) has traditionally been used to provide non-invasive respiratory support in these children, but there is little clinical trial evidence to support its use. More recently, high-flow nasal cannula therapy (HFNC) has emerged as a novel respiratory support modality. Our study aims to describe current national practice and clinician preferences relating to use of non-invasive respiratory support (nCPAP and HFNC) in the management of infants (<12 months old) with acute bronchiolitis.

Methods

We performed a cross-sectional web-based survey of hospitals with inpatient paediatric facilities in England and Wales. Responses were elicited from one senior doctor and one senior nurse at each hospital. We analysed the proportion of hospitals using HFNC and nCPAP; clinical thresholds for their initiation; and clinician preferences regarding first-line support modality and future research.

Results

The survey was distributed to 117 of 171 eligible hospitals; 97 hospitals provided responses (response rate: 83%). The majority of hospitals were able to provide nCPAP (89/97, 91.7%) or HFNC (71/97, 73.2%); both were available at 65 hospitals (67%). nCPAP was more likely to be delivered in a ward setting in a general hospital, and in a high dependency setting in a tertiary centre. There were differences in the oxygenation and acidosis thresholds, and clinical triggers such as recurrent apnoeas or work of breathing that influenced clinical decisions, regarding when to start nCPAP or HFNC. More individual respondents with access to both modalities (74/106, 69.8%) would choose HFNC over nCPAP as their first-line treatment option in a deteriorating child with bronchiolitis.

Conclusions

Despite lack of randomised trial evidence, nCPAP and HFNC are commonly used in British hospitals to support infants with acute bronchiolitis. HFNC appears to be currently the preferred first-line modality for non-invasive respiratory support due to perceived ease of use.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-017-0785-0) contains supplementary material, which is available to authorized users.

High-flow oxygen therapy is more cost-effective for bronchiolitis than standard treatment-A decision-tree analysis

We evaluated the cost-effectiveness of high-flow nasal cannula (HFNC) to provide additional oxygen for infants with bronchiolitis, compared to standard low-flow therapy. The cost-effectiveness was evaluated by decision analyses, using decision tree modeling, and was based on real costs from our recently published retrospective case-control study. The data on the effectiveness of HFNC treatment were collected from earlier published retrospective studies, using admission rates to pediatric intensive care units (PICU). The analyses in the study showed that the expected treatment costs of each episode of infant bronchiolitis varied between €1,312-2,644 ($1,786-3,600) in the HFNC group and €1,598-3,764 ($2,175-5,125) in the standard treatment group. The PICU admission rates and consequential costs were lower for HFNC than for standard treatment. HFNC treatment proved more cost-effective than standard treatment in all the baseline analyses and was also more cost-effective in the sensitivity analyses, except for in the worst-case scenario analysis. In conclusion, our modeling demonstrated that HFNC was strongly cost-effective for infant bronchiolitis, compared to standard treatment because it was both more effective and less expensive. Thus, if children hospitalized for bronchiolitis need oxygen, it should be delivered as HFNC treatment. Pediatr Pulmonol. 2016;51:1393-1402. © 2016 Wiley Periodicals, Inc.

Nasal high-flow therapy reduces work of breathing compared with oxygen during sleep in COPD and smoking controls: a prospective observational study

Patients with chronic obstructive pulmonary disease (COPD) endure excessive resistive and elastic loads leading to chronic respiratory failure. Oxygen supplementation corrects hypoxemia but is not expected to reduce mechanical loads. Nasal high-flow (NHF) therapy supports breathing by reducing dead space, but it is unclear how it affects mechanical loads of patients with COPD. The objective of this study was to compare the effects of low-flow oxygen and NHF therapy on ventilation and work of breathing (WOB) in patients with COPD and controls during sleep. Patients with COPD (n = 12) and controls (n = 6) were recruited and submitted to polysomnography to measure sleep parameters and ventilation in response to administration of oxygen and NHF. A subset of six patients also had an esophageal catheter inserted for the purpose of measuring WOB. Patients with COPD had similar minute ventilation (V̇e) but lower tidal volumes than matched controls. With oxygen, [Formula: see text]was increased and V̇e was reduced in both controls and patients with COPD, but there was an increase in transcutaneous CO₂ levels. NHF produced a greater reduction in V̇e and was associated with a reduction in CO₂ levels. Although NHF halved WOB, oxygen produced only a minor reduction in this parameter. We conclude that oxygen produced little change in WOB, which was associated with CO₂ elevations. On the other hand, NHF produced a large reduction in V̇e and WOB with a concomitant decrease in CO₂ levels. Our data indicate that NHF improves alveolar ventilation during sleep compared with oxygen and room air in patients with COPD and therefore can decrease their cost of breathing.

NEW & NOTEWORTHY

Nasal high-flow (NHF) therapy can support ventilation in patients with chronic obstructive pulmonary disease during sleep by decreasing the work of breathing and improving CO₂ levels. On the other hand, oxygen supplementation corrects hypoxemia, but it produces only a minimal reduction in work of breathing and is associated with increased CO₂ levels. Therefore, NHF can be a useful method to assist ventilation in patients with increased respiratory mechanical loads.

Using a high-flow nasal cannula provided superior results to low-flow oxygen delivery in moderate to severe bronchiolitis

AIM

An observational study was carried out on infants with moderate to severe bronchiolitis to compare the clinical outcomes following treatment with a high-flow nasal cannula (HFNC) or standard low-flow oxygen.

METHODS

We enrolled subjects below 12 months of age who were affected by their first bronchiolitis episode. Non-formal randomisation, based on HFNC availability, was used to assign subjects to either the HFNC or standard oxygen groups. Respiratory rate, respiratory effort and the ability to feed were compared between the two groups at enrolment and at regular time points. The oxygen requirements and the length of hospital stay were also analysed.

RESULTS

Overall, 36 of the 40 enrolled infants completed the study: 18 treated with HFNC (mean age 3.2 months, range 1.2-5.4 months) and 18 with low-flow oxygen delivery (mean age 3.6 months, range 1.3-5.0 months). Improvements in the respiratory rate, respiratory effort and ability to feed were significantly faster in the HFNC group than the low-flow oxygen group. The HNFC group needed oxygen supplementation for two days less than the other group and hospital stays were three days shorter.

CONCLUSION

HFNC provided superior clinical outcomes for infants under 12 months with moderate-to-severe bronchiolitis compared to low-flow oxygen.

High flow nasal cannula in children: a literature review

High flow nasal cannula (HFNC) is a relatively new non-invasive ventilation therapy that seems to be well tolerated in children. Recently a marked increase in the use of HFNC has been seen both in paediatric and adult care settings. The aim of this study was to review the current knowledge of HFNC regarding mechanisms of action, safety, clinical effects and tolerance in children beyond the newborn period.We performed a systematic search of the databases PubMed, Medline, EMBASE and Cochrane up to 12th of May 2016. Twenty-six clinical studies including children on HFNC beyond the newborn period with various respiratory diseases hospitalised in an emergency department, paediatric intensive care unit or general ward were included. Five of these studies were interventional studies and 21 were observational studies. Thirteen studies included only children with bronchiolitis, while the other studies included children with various respiratory conditions. Studies including infants hospitalised in a neonatal ward, or adults over 18 years of age, as well as expert reviews, were not systematically evaluated, but discussed if appropriate.The available studies suggest that HFNC is a relatively safe, well-tolerated and feasible method for delivering oxygen to children with few adverse events having been reported. Different mechanisms including washout of nasopharyngeal dead space, increased pulmonary compliance and some degree of distending airway pressure may be responsible for the effect. A positive clinical effect on various respiratory parameters has been observed and studies suggest that HFNC may reduce the work of breathing. Studies including children beyond the newborn period have found that HFNC may reduce the need of continuous positive airway pressure (CPAP) and invasive ventilation, but these studies are observational and have a low level of evidence. There are no international guidelines regarding flow rates and the optimal maximal flow for HFNC is not known, but few studies have used a flow rate higher than 10 L/min for infants.Until more evidence from randomized studies is available, HFNC may be used as a supplementary form of respiratory support in children, but with a critical approach regarding effect and safety, particularly when operated outside of a paediatric intensive care unit.

Pediatric Pulmonology year in review 2015: Part 1

Our journal covers a broad range of research and scholarly topics related to children's respiratory disorders. For updated perspectives on the rapidly expanding knowledge in our field, we will summarize the past year's publications in our major topic areas, as well as selected publications in these areas from the core clinical journal literature outside our own pages. The current review covers articles on neonatal lung disease, pulmonary physiology, and respiratory infection. Pediatr Pulmonol. 2016;51:733-739. © 2016 Wiley Periodicals, Inc.

Respiratory support for children in the emergency department

Respiratory support in paediatric emergency settings ranges from oxygen delivery with subnasal oxygen to invasive mechanical ventilation. Recent data suggest that oxygen can cause reperfusion injuries and should be delivered with caution within well-defined clinical target ranges. Most mild to moderate respiratory distress conditions with an oxygen requirement may benefit from early use of continuous positive airway pressure. High-flow nasal cannula therapy (HFNC) is an emerging alternative way to support the inspiratory effort combined with oxygen delivery and positive expiratory pressures without the need of complicated equipment or good compliance from the child. Besides a positive pressure support effect, HFNC therapy reduces the physiological dead space with improved CO2 clearance. A decrease in heart and respiratory rate within the first few hours after initiation of HFNC therapy is likely to identify responders of the treatment. The use of non-invasive ventilation such as continuous positive airway pressure or the use of bi-level positive airway pressure ventilation in emergency departments has increased, and it has been recognised that continuous positive airway pressure support for older children with asthma is particularly efficient.

CPAP and High-Flow Nasal Cannula Oxygen in Bronchiolitis

Severe respiratory failure develops in some infants with bronchiolitis because of a complex pathophysiologic process involving increased airways resistance, alveolar atelectasis, muscle fatigue, and hypoxemia due to mismatch between ventilation and perfusion. Nasal CPAP and high-flow nasal cannula (HFNC) oxygen may improve the work of breathing and oxygenation. Although the mechanisms behind these noninvasive modalities of respiratory support are not well understood, they may help infants by way of distending pressure and delivery of high concentrations of warmed and humidified oxygen. Observational studies of varying quality have suggested that CPAP and HFNC may confer direct physiologic benefits to infants with bronchiolitis and that their use has reduced the need for intubation. No trials to our knowledge, however, have compared CPAP with HFNC in bronchiolitis. Two randomized trials compared CPAP with oxygen delivered by low-flow nasal cannula or face mask and found some improvements in blood gas results and some physiologic parameters, but these trials were unable to demonstrate a reduction in the need for intubation. Two trials evaluated HFNC in bronchiolitis (one comparing it with headbox oxygen, the other with nebulized hypertonic saline), with the results not seeming to suggest important clinical or physiologic benefits. In this article, we review the pathophysiology of respiratory failure in bronchiolitis, discuss these trials in detail, and consider how future research studies may be designed to best evaluate CPAP and HFNC in bronchiolitis.

Early high flow nasal cannula therapy in bronchiolitis, a prospective randomised control trial (protocol): A Paediatric Acute Respiratory Intervention Study (PARIS)

Background

Bronchiolitis imposes the largest health care burden on non-elective paediatric hospital admissions worldwide, with up to 15 % of cases requiring admission to intensive care. A number of previous studies have failed to show benefit of pharmaceutical treatment in respect to length of stay, reduction in PICU admission rates or intubation frequency. The early use of non-invasive respiratory support devices in less intensive scenarios to facilitate earlier respiratory support may have an impact on outcome by avoiding progression of the disease process. High Flow Nasal Cannula (HFNC) therapy has emerged as a new method to provide humidified air flow to deliver a non-invasive form of positive pressure support with titratable oxygen fraction. There is a lack of high-grade evidence on use of HFNC therapy in bronchiolitis.

Methods/Design

Prospective multi-centre randomised trial comparing standard treatment (standard subnasal oxygen) and High Flow Nasal Cannula therapy in infants with bronchiolitis admitted to 17 hospitals emergency departments and wards in Australia and New Zealand, including 12 non-tertiary regional/metropolitan and 5 tertiary centres. The primary outcome is treatment failure; defined as meeting three out of four pre-specified failure criteria requiring escalation of treatment or higher level of care; i) heart rate remains unchanged or increased compared to admission/enrolment observations, ii) respiratory rate remains unchanged or increased compared to admission/enrolment observations, iii) oxygen requirement in HFNC therapy arm exceeds FiO₂ ≥ 40 % to maintain SpO₂ ≥ 92 % (or ≥94 %) or oxygen requirement in standard subnasal oxygen therapy arm exceeds >2L/min to maintain SpO₂ ≥ 92 % (or ≥94 %), and iv) hospital internal Early Warning Tool calls for medical review and escalation of care. Secondary outcomes include transfer to tertiary institution, admission to intensive care, length of stay, length of oxygen treatment, need for non-invasive/invasive ventilation, intubation, adverse events, and cost.

Discussion

This large multicenter randomised trial will allow the definitive assessment of the efficacy of HFNC therapy as compared to standard subnasal oxygen in the treatment of bronchiolitis.

Trial registration

The trial is registered with the Australian and New Zealand Clinical Trials Registry ACTRN12613000388718 (registered on 10 April 2013).

High-flow nasal cannulae are associated with increased diaphragm activation compared with nasal continuous positive airway pressure in preterm infants

AIM

High-flow nasal cannulae (HFNC) are increasingly used for respiratory management of preterm infants. However, their ability to provide support compared to nasal continuous positive airway pressure (CPAP) has been questioned. We compared the effect of HFNC versus nasal CPAP on diaphragm electrical activity (EAdi) in preterm infants.

METHODS

Preterm infants ≤1500 g were randomised in a crossover design to receive 2 hours of either Infant Flow(®) CPAP (IF-CPAP) at 5-6 cmH2 O or HFNC with the flow rate adjusted to achieve an equivalent pharyngeal pressure. A feeding catheter with miniaturised sensors was inserted for continuous EAdi measurement.

RESULTS

The study comprised ten infants. Physiologic parameters and oxygen requirements were not different between the two modes. However, seven infants demonstrated a higher EAdi peak and six showed a higher EAdi tonic on HFNC, even though the mean group data showed no difference between HFNC and IF-CPAP. Neural inspiratory time was significantly longer with HFNC than IF-CPAP (0.55 ± 0.11 versus 0.48 ± 0.06 seconds, p = 0.018).

CONCLUSION

In this cohort of preterm infants, the majority exhibited greater diaphragm activation, as assessed by neural breathing patterns, when supported with HFNC than IF-CPAP, suggesting that nasal CPAP may provide more effective respiratory support.

High-flow nasal cannula: recommendations for daily practice in pediatrics

High-flow nasal cannula (HFNC) is a relatively new device for respiratory support. In pediatrics, HFNC use continues to increase as the system is easily set up and is well tolerated by patients. The use of nasal cannula adapted to the infant’s nares size to deliver heated and humidified gas at high flow rates has been associated with improvements in washout of nasopharyngeal dead space, lung mucociliary clearance, and oxygen delivery compared with other oxygen delivery systems. HFNC may also create positive pharyngeal pressure to reduce the work of breathing, which positions the device midway between classical oxygen delivery systems, like the high-concentration face mask and continuous positive airway pressure (CPAP) generators. Currently, most of the studies in the pediatric literature suggest the benefits of HFNC therapy only for moderately severe acute viral bronchiolitis. But, the experience with this device in neonatology and adult intensive care may broaden the pediatric indications to include weaning from invasive ventilation and acute asthma. As for any form of respiratory support, HFNC initiation in patients requires close monitoring, whether it be for pre- or inter-hospital transport or in the emergency department or the pediatric intensive care unit.