Effect of a high-flow open nasal cannula system on obstructive sleep apnea in children

Comparison of high flow nasal cannula therapy to nasal oxygen as a treatment for obstructive sleep apnea in infants

INTRODUCTION

Obstructive sleep apnea (OSA) in infants is treated with low flow oxygen via nasal cannula (NC), CPAP (continous positive airway pressure), or surgery. Literature supports the use of high flow NC (HFNC) in children in the outpatient setting, however there is limited data on the use of HFNC in infants.

OBJECTIVE

The purpose of this study was to compare HFNC and low-flow oxygen as treatments for OSA in infants.

METHODS

A prospective pilot study was performed at two institutions. Infants with primarily OSA underwent a 3-4 h sleep study with HFNC titration at 6-14 lpm for OSA, followed by clinical polysomnography (PSG) for oxygen titration (1/8-1 lpm). Infants with primarily central apnea were excluded.

RESULTS

Nine infants were enrolled, with a mean age of 1.3 ± 1.7 months. Average apnea hypopnea index (AHI), average obstructive apnea hypopnea index (OAHI) and average central apnea index during the diagnostic PSG was 17.2 ± 7/h, 13.4 ± 5.4/h and 3.7 ± 4.8/h respectively. OSA improved in 44.4% of subjects with HFNC; the mean AHI and OAHI decreased from 15.6 ± 5.65/h and 12.8 ± 4.4/h on diagnostic PSG to 5.12 ± 2.5/h and 4.25 ± 2.5/h on titration PSG. OSA improved universally with low flow oxygen; the mean AHI decreased from 17.2 ± 7/h on diagnostic PSG to 4.44 ± 3.6/h on titration PSG.

CONCLUSION

HFNC reduced OSA in some infants, though low flow oxygen reduced OSA in all subjects. Respiratory instability (high loop gain) in infants may explain why infants responded to low flow oxygen. More studies are needed to determine if HFNC is beneficial in selected groups of infants with OSA.

Advances in Sleep-Disordered Breathing in Children

Pediatric sleep-disordered breathing disorders are a group of common conditions, from habitual snoring to obstructive sleep apnea (OSA) syndrome, affecting a significant proportion of children. The present article summarizes the current knowledge on diagnosis and treatment of pediatric OSA focusing on therapeutic and surgical advancements in the field in recent years. Advancements in OSA such as biomarkers, improving continuous pressure therapy adherence, novel pharmacotherapies, and advanced surgeries are discussed.

In-Line Aerosol Therapy via Nasal Cannula during Adult and Paediatric Normal, Obstructive, and Restrictive Breathing

High-flow nasal oxygen therapy is being increasingly adopted in intensive and home care settings. The concurrent delivery of aerosolised therapeutics allows for the targeted treatment of respiratory illnesses. This study examined in-line aerosol therapy via a nasal cannula to simulated adult and paediatric models with healthy, obstructive and restrictive lung types. The Aerogen Solo vibrating mesh nebuliser was used in combination with the InspiredTM O2FLO high-flow therapy system. Representative adult and paediatric head models were connected to a breathing simulator, which replicated several different states of lung health. The aerosol delivery was quantified at the tracheal level using UV-spectrophotometry. Testing was performed at a range of supplemental gas flow rates applicable to both models. Positive end-expiratory pressure was measured pre-, during and post-nebulisation. The increases in supplemental gas flow rates resulted in a decrease in aerosol delivery, irrespective of lung health. Large tidal volumes and extended inspiratory phases were associated with the greatest aerosol delivery. Gas flow to inspiratory flow ratios of 0.29-0.5 were found to be optimum for aerosol delivery. To enhance aerosol delivery to patients receiving high-flow nasal oxygen therapy, respiratory therapists should keep supplemental gas-flow rates below the inspiratory flow of the patient.

Medical Treatment of Obstructive Sleep Apnea in Children

Obstructive sleep apnea (OSA) is characterized by recurrent complete or partial obstruction of the upper airway. The prevalence is 1-4% in children aged between 2 and 8 years and rising due to the increase in obesity rates in children. Although persistent OSA following adenotonsillectomy is usually associated with obesity and underlying complex disorders, it can also affect otherwise healthy children. Medical treatment strategies are frequently required when adenotonsillectomy is not indicated in children with OSA or if OSA is persistent following adenotonsillectomy. Positive airway pressure treatment is a very effective modality for persistent OSA in childhood; however, adherence rates are low. The aim of this review article is to summarize medical treatment options for OSA in children.

Heated humidified high flow nasal cannula therapy in children with obstructive sleep apnea: A randomized cross-over trial

OBJECTIVE/BACKGROUND

Moderate-to-severe obstructive sleep apnea (OSA) is highly prevalent in children with obesity and/or underlying medical complexity. The first line of therapy, adenotonsillectomy (AT), does not cure OSA in more than 50% of these children. Consequently, continuous positive airway pressure (CPAP) is the main therapeutic option but adherence is often poor. A potential alternative which may be associated with greater adherence is heated high-flow nasal cannula (HFNC) therapy; however, its efficacy in children with OSA has not been systematically investigated. The study aimed to compare the efficacy of HFNC with CPAP to treat moderate-to-severe OSA with the primary outcome measuring the change from baseline in the mean obstructive apnea/hypopnea index (OAHI).

PARTICIPANTS/METHODS

This was a single-blinded randomized, two period crossover trial conducted from March 2019 to December 2021 at a Canadian pediatric quaternary care hospital. Children aged 2-18 years with obesity and medical complexity diagnosed with moderate-to-severe OSA via overnight polysomnography and recommended CPAP therapy were included in the study. Following diagnostic polysomnography, each participant completed two further sleep studies; a HFNC titration study and a CPAP titration study (9 received HFNC first, and 9 received CPAP first) in a random 1:1 allocation order.

RESULTS

Eighteen participants with a mean ± SD age of 11.9 ± 3.8 years and OAHI 23.1 ± 21.7 events/hour completed the study. The mean [95% CI] reductions in OAHI (-19.8[-29.2, -10.5] vs. -18.8 [-28.2, -9.4] events/hour, p = 0.9), nadir oxygen saturation (7.1[2.2, 11.9] vs. 8.4[3.5, 13.2], p = 0.8), oxygen desaturation index (-11.6[-21.0, -2.3] vs. -16.0[-25.3, -6.6], p = 0.5) and sleep efficiency (3.5[-4.8, 11.8] vs. 9.2[0.9, 15.5], p = 0.2) with HFNC and CPAP therapy were comparable between conditions.

CONCLUSION

HFNC and CPAP therapy yield similar reductions in polysomnography quantified measures of OSA severity among children with obesity and medical complexities.

TRIAL REGISTRATION

NCT05354401 ClinicalTrials.gov.

What’s New in Pediatric Obstructive Sleep Apnea?

Obstructive sleep apnea (OSA) is common children. There is a demand for more family-focused evaluation and novel diagnostic approaches. Drug-induced sleep endoscopy is increasingly being used clinically in children with Down syndrome and other comorbidities. Several studies have examined the association between OSA and other comorbidities during childhood. Therapeutic options for OSA in children remain limited. Recent studies have examined the utility of hypoglossal nerve stimulation in children with Down syndrome. Positive airway pressure has been a mainstay of OSA treatment. Several recent studies have assessed factors associated with adherence. Infants are challenging to treat for OSA.

Persistent obstructive sleep apnoea in children: treatment options and management considerations

Unresolved obstructive sleep apnoea (OSA) after an adenotonsillectomy, henceforth referred to as persistent OSA, is increasingly recognised in children (2-18 years). Although associated with obesity, underlying medical complexity, and craniofacial disorders, persistent OSA also occurs in otherwise healthy children. Inadequate treatment of persistent OSA can lead to long-term adverse health outcomes beyond childhood. Positive airway pressure, used as a one-size-fits-all primary management strategy for persistent childhood OSA, is highly efficacious but has unacceptably low adherence rates. A pressing need exists for a broader, more effective management approach for persistent OSA in children. In this Personal View, we discuss the use and the need for evaluation of current and novel therapeutics, the role of shared decision-making models that consider patient preferences, and the importance of considering the social determinants of health in research and clinical practice. A multipronged, comprehensive approach to persistent OSA might achieve better clinical outcomes in childhood and promote health equity for all children.

Heated Humidified High-Flow Nasal Cannula in Children: State of the Art

High-flow nasal cannula (HFNC) therapy is a non-invasive ventilatory support that has gained interest over the last ten years as a valid alternative to nasal continuous positive airway pressure (nCPAP) in children with respiratory failure. Its safety, availability, tolerability, and easy management have resulted its increasing usage, even outside intensive care units. Despite its wide use in daily clinical practice, there is still a lack of guidelines to standardize the use of HFNC. The aim of this review is to summarize current knowledge about the mechanisms of action, safety, clinical effects, and tolerance of HFNC in children, and to propose a clinical practices algorithm for children with respiratory failure.

Positive airway pressure for the treatment of the childhood obstructive sleep apnea syndrome

In this review, we have summarized the benefits of treatment with positive airway pressure for the childhood obstructive sleep apnea syndrome and presented a socio-ecological framework to enhance our understanding of positive airway pressure adherence predictors and important targets of comprehensive positive airway pressure treatment models across different pediatric populations. Although positive airway pressure is clearly a beneficial treatment for pediatric obstructive sleep apnea syndrome, additional research is needed to evaluate how socio-ecological factors may interact to predict positive airway pressure adherence, with more attention to the impact of the broader healthcare setting and on treatment approaches and outcomes in special pediatric populations.

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.

Immediate Physiological Responses to Inspiratory Flow Limited Events in Mild Obstructive Sleep Apnea

Rationale: Inspiratory flow limitation (IFL), characterized by flattening of individual breaths on the airflow/time tracing, is a noninvasive indicator of elevated upper airway resistance. An IFL "event" in isolation has not been defined, nor has the ability to reproducibly identify event occurrence been tested. IFL events and their association with immediate physiological responses-as well as the impact of characteristics such as age, sex, sleep stage, sleepiness, and event duration on their association with such outcomes-have not been studied. Symptomatic patients with a normal to mildly abnormal apnea-hypopnea index who have predominant IFL on their polysomnography may benefit from treatment. Objectives: To test the reproducibility of identifying IFL events and their termination and to determine the frequency of the immediate physiological response to their occurrence, including desaturation, electroencephalography (EEG) arousal, and increased heart rate (HR). Methods: Fifty-eight patients with obstructive sleep apnea (OSA) underwent full diagnostic polysomnography. IFL events and their termination were identified manually using predefined rules from the unscored nasal cannula flow channel alone and were evaluated for responses such as EEG arousal, oxygen desaturation of ⩾3%, and HR increase. Results: Interscorer reliability was acceptable, with an average percent agreement for occurrence of 82% ± 3%. Of all IFL events, 24% (regardless of the definition) were not associated with an EEG arousal, an increase in HR, or O₂ desaturation. Of all IFL events scored, 25% caused O₂ desaturation, 40% were associated with an EEG arousal, and 55% were associated with an increase in HR; 67% caused either an EEG arousal and/or an increase in HR. Responses were observed to occur either in isolation or in combination. IFL events that terminated with at least two non-IFL breaths, one of which had a 200% increase in amplitude, were significantly associated with O₂ desaturation, EEG arousal, and increase in HR compared with events that ended in one non-IFL breath. IFL events that had a >50% reduction in flow amplitude compared with baseline were significantly associated with O₂ desaturation compared with events that had a 30% reduction or less. Conclusions: Most IFL events resulted in immediate physiological responses, and no single consequence reliably occurred after every event. We propose a framework that can incorporate the scoring of IFL events into assessing the diagnosis and severity of OSA and suggest that no single consequence be used to define IFL as a respiratory event. The relationship of IFL events to OSA outcomes remains to be tested.

Comparison of airway pressures and expired gas washout for nasal high flow versus CPAP in child airway replicas

Background

For children and adults, the standard treatment for obstructive sleep apnea is the delivery of continuous positive airway pressure (CPAP). Though effective, CPAP masks can be uncomfortable to patients, contributing to adherence concerns. Recently, nasal high flow (NHF) therapy has been investigated as an alternative, especially in CPAP-intolerant children. The present study aimed to compare and contrast the positive airway pressures and expired gas washout generated by NHF versus CPAP in child nasal airway replicas.

Methods

NHF therapy was investigated at a flow rate of 20 L/min and compared to CPAP at 5 cmH₂O and 10 cmH₂O for 10 nasal airway replicas, built from computed tomography scans of children aged 4–8 years. NHF was delivered with three different high flow nasal cannula models provided by the same manufacturer, and CPAP was delivered with a sealed nasal mask. Tidal breathing through each replica was imposed using a lung simulator, and airway pressure at the trachea was recorded over time. For expired gas washout measurements, carbon dioxide was injected at the lung simulator, and end-tidal carbon dioxide (EtCO₂) was measured at the trachea. Changes in EtCO₂ compared to baseline values (no intervention) were assessed.

Results

NHF therapy generated an average positive end-expiratory pressure (PEEP) of 5.17 ± 2.09 cmH₂O (mean ± SD, n = 10), similar to PEEP of 4.95 ± 0.03 cmH₂O generated by nominally 5 cmH₂O CPAP. Variation in tracheal pressure was higher between airway replicas for NHF compared to CPAP. EtCO₂ decreased from baseline during administration of NHF, whereas it increased during CPAP. No statistical difference in tracheal pressure nor EtCO₂ was found between the three high flow nasal cannulas.

Conclusion

In child airway replicas, NHF at 20 L/min generated average PEEP similar to CPAP at 5 cm H₂O. Variation in tracheal pressure was higher between airway replicas for NHF than for CPAP. The delivery of NHF yielded expired gas washout, whereas CPAP impeded expired gas washout due to the increased dead space of the sealed mask.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01880-z.

Physiological Responses and Perceived Comfort to High Flow Nasal Cannula Therapy in Awake Adults: Effects of Flow Magnitude and Temperature

Clinical use of heated, high flow nasal cannula (HFNC) for non-invasive respiratory support is increasing and may have a therapeutic role in stabilizing the upper airway in obstructive sleep apnea (OSA). However, physiological mechanisms by which HFNC therapy may improve upper-airway function and effects of different temperature modes are unclear. Accordingly, this study aimed to determine effects of incremental flows and temperature modes (heated and non-heated) of HFNC on upper airway muscle activity (genioglossus), pharyngeal airway pressure, breathing parameters and perceived comfort. Six participants (2 females, aged 35±14 years) were studied during wakefulness in supine position and received HFNC at variable flows (0-60 L/min) during heated (37ºC) and non-heated (21ºC) modes. Breathing parameters via calibrated Respitrace inductance bands (chest and abdomen), upper-airway pressures via airway transducers, and genioglossus muscle activity via intra-muscular bipolar fine wire electrodes were measured. Comfort levels during HFNC were quantified using a visual analogue scale. Increasing HFNC flows did not increase genioglossus muscle activation despite increased negative epiglottic pressure swings (p=0.009). HFNC provided ~7cmH₂O positive airway pressure at 60 L/min in non-heated and heated modes. In addition, increasing the magnitude of HFNC flow reduced breathing frequency (p=0.045), increased expiratory time (p=0.040), increased peak inspiratory flow (p=0.002), and increased discomfort (p=0.004). Greater discomfort occurred at higher flows in non-heated versus heated mode (p=0.034). These findings provide novel insight into key physiological changes that occur with HFNC for respiratory support and indicate the primary mechanism for improved upper-airway stability is positive airway pressure, not increased pharyngeal muscle activity.

High flow versus conventional nasal cannula for oxygenation and ventilation maintenance during surgery with intravenous deep sedation by propofol: a randomized controlled study

Background

The dead space washout and provision of some level of positive airway pressure by nasal high-flow (NHF) cannula could improve the efficiency of ventilation, oxygenation and maintenance of the upper airway in patients undergoing deep sedation. This study aimed to compare the incidences of events represented oxygenation and ventilation, i.e. desaturation and upper airway obstruction, and arterial blood gas (ABG) levels between using NHF cannula and conventional nasal cannula (NC2) during deep sedation of adult surgical patients.

Methods

In this prospective randomized single-blinded study, the patients who were 20–80 years old, ASA physical status of 1 to 3, scheduled for surgery under intravenous sedation (IVS) were included. The patients were randomly divided into two groups, i.e., NC2 or NHF groups. Propofol infusion was given to maintain deep sedation. The desaturation (SpO₂ < 92%) and upper airway obstruction events (presence of snoring with paradoxical breathing) after application of NC2 or NHF were observed and collected. Other outcomes included interventions during IVS, such as jaw lifting or airway instrument insertion, mouth dryness, and post- ABG analyses were also collected and compared.

Results

Thirty-six patients undergoing endovascular surgery were randomized into NC2 or NHF groups (18 in each group). No patients dropped out of the study. There were no significant differences in age, sex, ASA physical status, pre-sedation and pre-application of NC2 and NHF ABG analyses (PaO₂, SaO₂, pH, PaCO₂, and PaO₂/FiO₂). NHF group had significantly lower in the incidence of desaturation [5 (27.78%) vs 13 (72.22%), p = 0.008], upper airway obstruction [4 (22.22%) vs 13 (72.22%), p = 0.003], and airway maneuver [6 (33.33%) vs 13 (72.22%), p = 0.019] than NC2 group. There were no differences in the ABG analyses after oxygen supplementation and no significant differences in mouth dryness between groups.

Conclusion

The use of NHF cannula in patients undergoing endovascular surgery under deep sedation reduced desaturation events and required fewer airway interventions than NC2 with no difference in arterial blood gas analyses and mouth dryness.

Effects of nasal high flow on sympathovagal balance, sleep, and sleep-related breathing in patients with precapillary pulmonary hypertension

BACKGROUND

In precapillary pulmonary hypertension (PH), nasal high flow therapy (NHF) may favorably alter sympathovagal balance (SVB) and sleep-related breathing through washout of anatomical dead space and alleviation of obstructive sleep apnea (OSA) due to generation of positive airway pressure.

OBJECTIVES

To investigate the effects of NHF on SVB, sleep, and OSA in patients with PH, and compare them with those of positive airway pressure therapy (PAP).

METHODS

Twelve patients with PH (Nice class I or IV) and confirmed OSA underwent full polysomnography, and noninvasive monitoring of SVB parameters (spectral analysis of heart rate, diastolic blood pressure variability). Study nights were randomly split into four 2-h segments with no treatment, PAP, NHF 20 L/min, or NHF 50 L/min. In-depth SVB analysis was conducted on 10-min epochs during daytime and stable N2 sleep at nighttime.

RESULTS

At daytime and compared with no treatment, NHF20 and NHF50 were associated with a flow-dependent increase in peripheral oxygen saturation but a shift in SVB towards increased sympathetic drive. At nighttime, NHF20 was associated with increased parasympathetic drive and improvements in sleep efficiency, but did not alter OSA severity. NHF50 was poorly tolerated. PAP therapy improved OSA but had heterogenous effects on SVB and neutral effects on sleep outcomes. Hemodynamic effects were neutral for all interventions.

CONCLUSIONS

In sleeping PH patients with OSA NHF20 but not NHF50 leads to decreased sympathetic drive likely due to washout of anatomical dead space. NHF was not effective in lowering the apnea-hypopnoea index and NHF50 was poorly tolerated.

Paediatrics: how to manage obstructive sleep apnoea syndrome

Obstructive sleep apnoea syndrome (OSAS) is defined as the intermittent reduction or cessation of airflow due to partial or complete obstruction of the upper airway during sleep. Paediatric OSAS has specific contributing factors, presenting symptoms and management strategies in various age groups. Untreated OSAS can lead to detrimental effects on neurocognitive development and cardiovascular and metabolic functions of a growing child. In the past decade, practice guidelines have been developed to guide the evaluation and management of OSAS. This article provides a narrative review on the current diagnostic and treatment options for paediatric OSAS. Alternative diagnostic tools other than the standard polysomnography are discussed. Adenotonsillectomy is considered the first-line therapy yet it is not suitable for treatment of all OSAS cases. Nocturnal non-invasive positive airway pressure ventilation is effective and could be the priority treatment for patients with complex comorbidities, residual OSAS post-adenotonsillectomy or obesity. However, intolerance and non-adherence are major challenges of positive airway pressure therapy especially in young children. There is increasing evidence for watchful waiting and other gentler alternative treatment options in mild OSAS. The role of anti-inflammatory drugs as the primary or adjunctive treatment is discussed. Other treatment options, including weight reduction, orthodontic procedures and myofunctional therapy, are indicated for selected patients. Nevertheless, the successful management of paediatric OSAS often requires a multidisciplinary team approach.

Postextubation respiratory events in patients admitted to the intensive care unit: a prospective pilot study using overnight respiratory polygraphy

Background

Before the main trial in which respiratory polygraphy will be used to evaluate postextubation sleep apnea in critically ill patients, we performed a prospective pilot study to ensure that any issues with the conduct of the trial would be identified.

Methods

In the present study, 13 adult patients who had received mechanical ventilation for ≥24 hours were prospectively recruited. Among the patients, 10 successfully completed respiratory polygraphy on the first or second night after extubation. Data regarding the types and doses of corticosteroids, analgesics, sedatives, and muscle relaxants as well as the methods of oxygen delivery were recorded.

Results

During the night of respiratory polygraphy, all 10 patients received supplemental oxygen (low-flow oxygen, n=5; high-flow oxygen, n=5), and seven patients received intravenous corticosteroids. Three of the 10 patients had a respiratory event index (REI) ≥5/hr. All respiratory events were obstructive episodes. None of the patients receiving high-flow oxygen therapy had an REI ≥5/hr. Two of the seven patients who received corticosteroids and one of the other three patients who did not receive this medication had an REI ≥5/hr. Although low- or high-flow oxygen therapy was provided, all patients had episodes of oxygen saturation (SpO₂) <90%. Two of the three patients with an REI ≥5/hr underwent in-laboratory polysomnography. The patients’ Apnea-Hypopnea Index and REI obtained via polysomnography and respiratory polygraphy, respectively, were similar.

Conclusions

In a future trial to evaluate postextubation sleep apnea in critically ill patients, pre-stratification based on the use of corticosteroids and high-flow oxygen therapy should be considered.

High flow nasal cannula treatment for obstructive sleep apnea in infants and young children

BACKGROUND

Continuous positive airway pressure (CPAP) is the nonsurgical treatment of choice for children with obstructive sleep apnea (OSA). However, CPAP limitations include difficulty with adherence and midface hypoplasia risk. We, therefore, sought to assess the effect of warm humidified air delivered via open nasal cannula (HFNC) on OSA in children in the sleep laboratory and at home.

METHODS

A retrospective review was performed among children recommended treatment of OSA with HFNC. Reasons for HFNC recommendation included poor surgical candidacy, residual OSA following surgery, and CPAP intolerance. Children underwent both diagnostic and HFNC titration sleep studies and were prescribed HFNC for home use. Standard sleep architecture, arousals, and apnea-hypopnea indices (AHI) were assessed with the evaluation of reported adherence and complications over 12 months of treatment.

RESULTS

Twenty-two children (average 12.8 months, 95% confidence interval [95% CI: 7.0, 18.6]) with OSA (obstructive AHI [OAHI] range: 4.8-89.2 events/h) underwent HFNC titration with significant reduction in OAHI (28.9 events/h [17.6, 40.2] vs 2.6 [1.1, 4.0]; P < .001) (mean [95% CI]). Nineteen patients received home HFNC treatment. By 12 months, four patients were lost to follow-up and OSA resolved in three patients (16%). Of 12 remaining patients, 7 (58%) continued therapy while 5 (42%) discontinued due to intolerance. The most common treatment complication was cannula dislodgement. Additional complications included skin irritation, dry mucus membranes, restlessness, oxygen desaturation, and increased central apneas.

CONCLUSION

HFNC offers a treatment alternative to CPAP in infants and young children with OSA and was well tolerated at home in our study.

Use of heated humidified high flow nasal cannula for obstructive sleep apnea in infants

OBJECTIVE

Heated humidified high flow nasal cannula (HHHFNC) has gained popularity in the treatment of children with respiratory distress and bronchiolitis in the past decade. Its efficacy as a mode of non-invasive respiratory support has been demonstrated in both adults and children. However, reports on its use in the treatment of obstructive sleep apnea (OSA) in infants are limited. We aimed to evaluate the efficacy of HHHFNC therapy as treatment in infants with OSA.

METHODS

A retrospective analysis of OSA infants who had undergone polysomnographic titration between 2015 and 2017 was undertaken. Data about the age, gender, AHI, co-morbid conditions and flow used for each patient were retrieved.

RESULTS

Ten infants were included in this study (median age 34 weeks; IQR 27-38 weeks). The median optimal HHHFNC flow rate was 8.0 L/min (IQR 6.7-8.0 L/min). HHHFNC significantly reduced median obstructive apnea-hypopnea index (OAHI) from 9.1 (IQR 5.1-19.3) to 0.9 (IQR 0-1.6; P = 0.005) events/h; median obstructive apnea index (OAI) from 5.8 (IQR 1.1-13.4) to 0 (IQR 0-0.9; P = 0.021) events/h; median obstructive hypopnea index (OHI) from 4.1 (IQR 0.9-6.8) to 0.1 (0-0.9; P = 0.017) events/h; and median oxygen saturation (SpO2) nadir increased from 88% (IQR 83-94%) to 94% (IQR 93-96%; P = 0.040).

CONCLUSION

HHHFNC significantly reduced respiratory events and improved oxygenation in infants with OSA.

Novel use of high-flow nasal cannula therapy in the management of pyriform aperture stenosis: case report

BACKGROUND

Pyriform aperture stenosis is a rare form of congenital nasal obstruction; it poses a management dilemma for otolaryngologists and physicians alike. It can result in poor weight gain and potentially life-threatening airflow obstruction. The challenge lies in the difficulty to predict which patients will require invasive operative management versus conservative therapy alone.

CASE REPORT

This case demonstrates the successful use of high-flow nasal cannula therapy in a young child with pyriform aperture stenosis.

High-flow nasal cannula ventilation therapy for obstructive sleep apnea in ischemic stroke patients requiring nasogastric tube feeding: a preliminary study

Obstructive sleep apnea (OSA) is associated with increasing risk of recurrent stroke and mortality. Nasogastric tubes used by dysphagic stroke patients may interfere with nasal continuous positive airway pressure (CPAP) due to air leakage. This study was evaluated the effects and short-term tolerability of high-flow nasal cannula (HFNC) therapy for OSA in stroke patients with nasogastric intubation. The HFNC titration study was performed in post-acute ischemic stroke patients with nasogastric intubation and OSA. Then, participants were treated with HFNC therapy in the ward for one week. Eleven participants (eight males) who were all elderly with a median age of 72 (IQR 67-82) years and a body mass index of 23.5 (IQR 22.0-26.6) completed the titration study. The HFNC therapy at a flow rate up to 50~60 L/min significantly decreased the apnea-hypopnea index from 52.0 events/h (IQR 29.9-61.9) to 26.5 events/h (IQR 3.3-34.6) and the total arousal index from 34.6 (IQR 18.6-42.3) to 15.0 (IQR 10.3-25.4). The oxygen desaturation index was also significantly decreased from 53.0 events/h (IQR 37.0-72.8) to 16.2 events/h (IQR 0.8-20.1), accompanied by a significant improvement in the minimum SpO2 level. Finally, only three participants tolerated flow rates of 50~60 L/minute in one-week treatment period. Conclusively, HFNC therapy at therapeutic flow rate is effective at reducing the OSA severity in post-acute ischemic stroke patients with nasogastric intubation. Owing to the suboptimal acceptance, HFNC might be a temporary treatment option, and CPAP therapy is suggested after the nasogastric tube is removed.

[Medical treatment of obstructive sleep-disordered breathing in children and adolescents]

Obstructive sleep disordered breathing (OSDB), in children and adolescents, need to be treated quite soon to avoid complications. A paediatrician, a sleep specialist, an orthodontist, an ENT and a myofunctional therapist will examine together the children with OSDB and determine the best personalised surgical and medical treatments for each of them. Only medical treatments are reviewed in this article. An international consensus recommended adenotonsillectomy as the first line therapy in young with OSDB. Usually adenotonsillectomy is combined with several important adjunctive medical treatments. Overweight and obesity frequent in adolescents, worsen OSDB and increase persistent OSDB after adenotonsillectomy. Weight loss is obtained by dietary restriction, physical activity, psychological support and sleep hygiene rules. Anti-inflammatory drugs (corticosteroids and leukotriene receptor antagonists) have shown their efficacy in children with moderate OSDB. Orthodontic treatments, rapid maxillary expansion or oral appliance, are used in selected patients according to their maxillo-facial disturbances in adjunction to adenotonsillectomy. Nasal CPAP is rarely useful except in severe OSDB specially in persistent OSDB after adenotonsillectomy. Finally, active or passive, myofunctional therapy is, according to some authors, an indispensable adjunct treatment to avoid persistent OSDB after adenotonsillectomy. These personalized medical treatments of OSDB are either administered jointly with adenotonsillectomy or in a hierarchal order.

Oxygen for the treatment of obstructive sleep apnoea hypopnoea syndrome

Oxygen, in the form of diatomic oxygen (O₂), comprises 20.8% of the Earth's atmosphere and is essential to most life forms on the planet. In 1777, Lavoisier was the first to name oxygen and recognise that it was a chemical element involved in combustion.

Nocturnal oxygen therapy cannot currently be recommended as a sole treatment for obstructive sleep apnoeahttp://bit.ly/2kuAsPU

[Adolescent obstructive sleep apnoea syndrome: Characteristics and treatment]

Although the prevalence of the obstructive sleep apnoea syndrome (OSAS) is high in adolescents, studies pertaining to adolescent OSAS are less numerous than childhood studies. Cases of adolescent OSAS may consist of residual OSAS after adenotonsillectomy, but most often are de novo cases. Major pathophysiological factors are weight excess or even high-grade obesity, and the association of upper airway narrowing and tonsillar hypertrophy (pharyngeal, palatal or even lingual). ENT and systematic orthodontic assessments are the main points. In case of predisposing factors such as dental, occlusal or dento-facial abnormalities, a specific orthodontic treatment can be discussed. First line treatment is surgical adenotonsillectomy; surgical reduction of the lingual tonsils is seldom required. CPAP treatment may be indicated in the case of severe comorbidities (craniofacial malformations, neuromuscular diseases…) or in obese adolescents with severe residual OSAS. Treatment of adolescent OSAS has to be comprehensive and multidisciplinary, taking into account the specific treatments of obesity and abnormal sleep/wake rhythms.

High-flow nasal cannula for children not compliant with continuous positive airway pressure

OBJECTIVES

Continuous positive airway pressure (CPAP) is an effective treatment of severe obstructive sleep apnea (OSA) but poor compliance is a major limitation. High-flow nasal cannula (HFNC) has been used as an alternative but data about efficacy and objective long-term compliance are scarce; this study aims to address this lack of data.

PATIENTS/METHODS

All consecutive patients, aged 0-18 years, treated with CPAP for a severe OSA defined as an apnea-hypopnea index (AHI) > 10 events/h, and not compliant with home CPAP therapy, defined by a CPAP use of <2 h/night, after at least four weeks from CPAP initiation were considered eligible for the study. HFNC was started during an outpatient visit. Study outcomes were the objective compliance (number of hours use/night) after one month and the improvement of OSA on a respiratory polygraphy (RP) with HFNC.

RESULTS

Eight patients (two boys, mean age 8.9 ± 6.2 years, mean AHI 33 ± 22 events/h) were included in the study: Down syndrome (N = 6), Pierre Robin syndrome (N = 1), Pfeiffer syndrome (N = 1). After one month, five (62%) patients slept with HFNC more than 4 h/night (mean compliance 7 h 10 min ± 0 h 36 min/night). HFNC corrected OSA in the five compliant patients (mean AHI 2 ± 2 events/h with HFNC). HFNC was not accepted by the three oldest patients with Down syndrome.

CONCLUSION

A good compliance as well as a correction of OSA may be obtained with HFNC in selected children with OSA not compliant to CPAP. HFNC may be used as a rescue therapy for children not compliant with CPAP.

A New Promising Treatment Strategy for Carbon Monoxide Poisoning: High Flow Nasal Cannula Oxygen Therapy

Background

High-flow nasal cannula (HFNC) is an alternative to conventional normobaric oxygen therapy (NBO) for hypoxemic patients. Since nothing is known about its effect on carbon monoxide (CO) poisoning, we hypothesized that HFNC might be a useful device in the treatment of CO poisoning victims.

Material/Methods

We retrospectively reviewed the medical records of patients who were admitted consecutively to the emergency department with CO intoxication. Patients were divided into 2 groups: patients treated with HFNC and patients treated with conventional face mask (CFM). Demographic data, pretreatment, and control (after 1 hour) arterial blood gas analyses values of the patients were evaluated.

Results

Sixty-eight patients (mean age 35.8±18.7 years) were included in this study. NBO was given via HFNC to 38 patients (55.9%), and via CFM to 30 patients (44.1%). The demographic characteristics and pretreatment values of carboxy-hemoglobin (COHb) were similar in the 2 groups. The mean COHb value of the HFNC group at the first hour was found significantly lower than the CFM group: 9.5±4.7 and 12.0±5.1, respectively (P=0.041). Improvement of COHb level was significantly higher in the HFNC group compared to the CFM group: 12.5±4.5 versus 6.7±3.7, respectively (P=0.001).

Conclusions

HFNC was superior than CFM in alleviating COHb levels in the victims of CO poisoning. We believe that using HFNC will increase patient comfort by shortening the duration of treatment in emergency department settings, especially in patients who have mild clinical findings of CO poisoning.

Reductions in dead space ventilation with nasal high flow depend on physiological dead space volume: metabolic hood measurements during sleep in patients with COPD and controls

Nasal high flow (NHF) reduces minute ventilation and ventilatory loads during sleep but the mechanisms are not clear. We hypothesised NHF reduces ventilation in proportion to physiological but not anatomical dead space.11 subjects (five controls and six chronic obstructive pulmonary disease (COPD) patients) underwent polysomnography with transcutaneous carbon dioxide (CO₂) monitoring under a metabolic hood. During stable non-rapid eye movement stage 2 sleep, subjects received NHF (20 L·min^-1) intermittently for periods of 5-10 min. We measured CO₂ production and calculated dead space ventilation.Controls and COPD patients responded similarly to NHF. NHF reduced minute ventilation (from 5.6±0.4 to 4.8±0.4 L·min^-1; p<0.05) and tidal volume (from 0.34±0.03 to 0.3±0.03 L; p<0.05) without a change in energy expenditure, transcutaneous CO₂ or alveolar ventilation. There was a significant decrease in dead space ventilation (from 2.5±0.4 to 1.6±0.4 L·min^-1; p<0.05), but not in respiratory rate. The reduction in dead space ventilation correlated with baseline physiological dead space fraction (r²=0.36; p<0.05), but not with respiratory rate or anatomical dead space volume.During sleep, NHF decreases minute ventilation due to an overall reduction in dead space ventilation in proportion to the extent of baseline physiological dead space fraction.

An Official American Thoracic Society Workshop Report: Noninvasive Identification of Inspiratory Flow Limitation in Sleep Studies

This report summarizes the proceedings of the American Thoracic Society Workshop on the Noninvasive Identification of Inspiratory Flow Limitation in Sleep Studies held on May 16, 2015, in Denver, Colorado. The goal of the workshop was to discuss methods for standardizing the scoring of flow limitation from nasal cannula pressure tracings. The workshop began with presentations on the physiology underlying flow limitation, existing methods of scoring flow limitation, the effects of signal acquisition and filtering on flow shapes, and a review of the literature examining the adverse outcomes related to flow limitation. After these presentations, the results from online scoring exercises, which were crowdsourced to workshop participants in advance of the workshop, were reviewed and discussed. Break-out sessions were then held to discuss potential algorithms for scoring flow limitation. Based on these discussions, subsequent online scoring exercises, and webinars after the workshop, a consensus-based set of recommendations for a scoring algorithm for flow limitation was developed. Key conclusions from the workshop were: (1) a standardized and automated approach to scoring flow limitation is needed to provide a metric of nonepisodic elevated upper airway resistance, which can then be related to clinical outcomes in large cohorts and patient groups; (2) at this time, the most feasible method for standardization is by proposing a consensus-based framework, which includes scoring rules, developed by experts (3) hardware and software settings of acquisition devices, including filter settings, affect the shape of the flow curve, and should be clearly specified; and (4) a priority for future research is the generation of an open-source, expert-derived training set to encourage and support validation of automated flow limitation scoring algorithms.

High-Flow, Heated, Humidified Air Via Nasal Cannula Treats CPAP-Intolerant Children With Obstructive Sleep Apnea

STUDY OBJECTIVES

Continuous positive airway pressure (CPAP) is effective but challenging for children with obstructive sleep apnea (OSA). High-flow air via open nasal cannula (HFNC) as treatment in children remains controversial. We report the efficacy of HFNC in children with OSA and CPAP intolerance, a titration protocol, and a discussion of potential mechanisms.

METHODS

Patients aged 1 to 18 years with OSA (defined by obstructive apnea-hypopnea index [OAHI] greater than 1 event/h) and CPAP intolerance were enrolled. Routine polysomnography data obtained during 1 night wearing HFNC was compared with diagnostic data by Wilcoxon rank-sum test.

RESULTS

Ten school-age subjects (representing all patients attempting HFNC at our institution to date) with varied medical conditions, moderate to severe OSA, and CPAP intolerance wore HFNC from 10 to 50 L/min of room air with oxygen supplementation if needed (room air alone for 6 of the 10). HFNC reduced median OAHI from 11.1 events/h (interquartile range 8.7-18.8 events/h) to 2.1 events/h (1.7-2.2 events/h; P = .002); increased oxyhemoglobin saturation (SpO₂) mean from 91.3% (89.6% to 93.5%) to 94.9% (92.4% to 96.0%; P < .002); increased SpO₂ nadir from 76.0% (67.3% to 82.3%) to 79.5% (77.2% to 86.0%; P = .032); decreased SpO₂ desaturation index from 19.2 events/h (12.7-25.8 events/h) to 6.4 events/h (4.7-10.7 events/h; P = .013); and reduced heart rate from 88 bpm (86-91 bpm) to 74 bpm (67-81 bpm; P = .004). Stratified analysis of the 6 subjects with only room air via HFNC, the OAHI, obstructive hypopnea index, and mean SpO₂ still demonstrated improvements (P = .031).

CONCLUSIONS

High-flow nasal cannula reduces respiratory events, improves oxygenation, reduces heart rate, and may be effective for CPAP intolerant children with moderate to severe OSA. Our data suggest HFNC warrants further study and consideration by payers as OSA therapy.

High-flow nasal cannula therapy beyond the perinatal period

PURPOSE OF REVIEW

High-flow nasal cannula (HFNC) is emerging as a means of oxygen delivery and respiratory support for a range of conditions outside the perinatal period. We aim to review the mechanisms of action and advantages of HFNC and to summarize current findings regarding clinical benefit in specific pediatric disease processes and in patients with significant respiratory distress.

RECENT FINDINGS

Currently published studies outside the neonatal population demonstrate both safety and efficacy of this mode of respiratory support. Retrospective and prospective observational trials have shown improvements in oxygenation and respiratory distress, as well as reductions in the need for intubation in select patient populations. Randomized controlled trials are ongoing.

SUMMARY

HFNC is emerging as a means of oxygen delivery and respiratory support across a wide range of pediatric conditions. Available data suggest that it is well tolerated by children and can have a favorable effect on clinical outcomes. Future research will better define optimal patient populations and best practices for use.

Non-surgical management of obstructive sleep apnoea: a review

BACKGROUND

Obstructive sleep apnoea is common in children and, if untreated, can lead to multiple medical sequelae. The Childhood Adenotonsillectomy Trial demonstrated benefit from early surgical intervention, but rapid access to such treatment is not always available.

AIMS

To examine the recent literature on non-surgical aspects of the management of paediatric obstructive sleep apnoea (OSA).

METHODS

The English language literature was searched for articles on the conservative management of OSA.

RESULTS

In mild cases of OSA, intra-nasal steroids and other anti-inflammatory medications may give relief in mild cases of OSA, but the long-term safety of these treatments has not been established. Weight loss in obese children has been shown to be effective in selected patients but is limited in practice. Non-invasive ventilation may be effective but compliance can be a major obstacle. Oral appliances are effective by stenting the pharyngeal airway, but research in this area is limited.

CONCLUSIONS

There are number of potential, if not proven, alternative management strategies for children with OSA, which could be considered in the absence of early surgical intervention.

Applications of Nasal High-Flow Oxygen Therapy in Critically ill Adult Patients

The use of nasal high-flow oxygen therapy (NHFOT) has become increasingly common in hospitals across Europe, Asia, and North America. These high utility devices provide an efficient and comfortable access points for providing supplemental oxygen to patients with variety of respiratory disorders. They are relatively easy to set up, and clinicians and patients alike give very positive feedback about their ease of use and comfort for patients in the hospital setting. However, it remains uncertain whether NHFOT improves patient survival or even reduces respiratory complications. Outcome data in adult populations are few and frequently underpowered to guide physicians for their widespread use in hospital setting. In this article, we present a review of the current technology and available studies pertinent to NHFOT.

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.

Nasal highflow improves ventilation in patients with COPD

Background

Nasal highflow (NHF) provides a warmed and humidified air stream up to 60 L/min. Recent data demonstrated a positive effect in patients with acute hypoxemic respiratory failure, especially when caused by pneumonia. Preliminary data show a decrease in hypercapnia in patients with COPD. Therefore, NHF should be evaluated as a new ventilatory support device. This study was conducted to assess the impact of different flow rates on ventilatory parameters in patients with COPD.

Materials and methods

This interventional clinical study was performed with patients suffering from severe COPD. The aim was to characterize flow-dependent changes in mean airway pressure, breathing volumes, breathing frequency, and decrease in partial pressure of CO₂ (pCO₂). Mean airway pressure was measured in the nasopharyngeal space (19 patients). To evaluate breathing volumes, we used a polysomnographic device (18 patients). All patients received 20 L/min, 30 L/min, 40 L/min, and 50 L/min and – to illustrate the effects – nasal continuous positive airway pressure and nasal bilevel positive airway pressure. Capillary blood gas analyses were performed in 54 patients with hypercapnic COPD before and two hours after the use of NHF. We compared the extent of decrease in pCO₂ when using 20 L/min and 30 L/min. Additionally, comfort and dyspnea during the use of NHF were surveyed.

Results

NHF resulted in a minor flow dependent increase in mean airway pressure. Tidal volume increased, and breathing rate decreased. The calculated minute volume decreased under NHF breathing. In spite of this fact, hypercapnia decreased with increasing flow (20 L/min vs 30 L/min). Additionally, an improvement in dyspnea was observed. The rapid shallow breathing index shows a decrease when using NHF.

Conclusion

NHF leads to a flow-dependent reduction in pCO₂. This is most likely achieved by a washout of the respiratory tract and a functional reduction in dead space. In summary, NHF enhances effectiveness of breathing in patients with COPD, reduces pCO₂, the work of breathing, and rapid shallow breathing index as an indicator of respiratory work load.

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.

Polysomnographic Markers in Children With Cystic Fibrosis Lung Disease

BACKGROUND AND OBJECTIVES

Children with cystic fibrosis (CF) often report poor sleep, increased daytime sleepiness, and fatigue. The purpose of this study was to identify respiratory patterns over the spectrum of disease severity in children with CF. The overall hypothesis for the current study is that children with CF compared with snoring control subjects demonstrate gas exchange abnormalities and increased respiratory loads during sleep that are not reported or recognized by conventional polysomnography (PSG).

METHODS

Analysis of breathing patterns and gas exchange on PSG was performed in children with CF and healthy controls matched by age and BMI. For all CF and control subjects, the indication for PSG was evaluation for obstructive sleep apnea based on a history of snoring.

RESULTS

Children with CF, compared with age- and BMI-matched snoring controls, demonstrated lower oxyhemoglobin saturation (95% ± 1.6% vs 98% ± 0.6%, P = .005), higher respiratory rate (19.5 ± 4.9 vs 16.5 ± 1.2 breaths per minute, P = .03), and a higher proportion of inspiratory flow limitation (44.1% ± 24.7% vs 12.1% ± 13.5%, P = .007) during non-rapid eye movement sleep. The respiratory disturbance index did not differ between CF and snoring control groups (1.5 ± 2.7 vs 0.6 ± 0.6 events per hour, P = .11).

CONCLUSIONS

Children with CF exhibited abnormalities in gas exchange and increased respiratory load during sleep compared with normal age- and BMI-matched snoring controls. Because these abnormalities were independent of weight and lung function, sleep state may serve as an opportunity for early detection of breathing abnormalities and possibly CF lung disease progression.

Sleep Disordered Breathing in Children

Sleep-disordered breathing (SDB) refers to a group of disorders characterized by abnormalities of respiration or ventilation during sleep. It encompasses obstructive sleep apnea (OSA), central sleep apnea (CSA) syndromes, sleep-related hypoventilation and sleep-related hypoxemia disorders. This review will concentrate on the disorder most prevalent in pediatrics, i.e., OSA, highlighting the most recent developments in our understanding of the etiology, pathophysiology and treatment options of this condition. OSA morbidities primarily involve the neurocognitive, cardiovascular and metabolic systems. However, there can be significant phenotypic variation in terms of end organ morbidity for the same OSA severity. This is likely due to the interplay between genetic and environmental factors; recent developments in the fields of genomics and proteomics have the potential to shed light on these complex pathological cascades. As we enter the era of personalized medicine, phenotyping patients to enable clinicians to tailor bespoke clinical management plans will be of crucial importance.

High-Flow Nasal Cannula Therapy for Obstructive Sleep Apnea in Children

INTRODUCTION

Over the last decade, high-flow nasal cannula (HFNC) therapy has become an increasingly important and popular mode of noninvasive respiratory support. HFNC facilitates delivery of humidified and heated oxygen at a high flow rate and generates positive airway pressure.

METHODS

We present five cases of children with OSA without adenotonsillar hypertrophy who were treated with HFNC.

RESULTS

We demonstrated a statistically significant improvement in apnea-hypopnea index and nadir oxygen saturation in this small cohort.

CONCLUSION

We present our successful experience of treating severe OSA with HFNC in the home setting. Further randomized controlled trials are needed to determine whether HFNC could be considered as an established alternative for CPAP in OSA in children.

Heated humidified high-flow nasal cannula therapy in children

Heated humidified high-flow nasal cannula therapy (HHHFNC) was originally described as a mode of respiratory support in premature neonates and is now increasingly used in the management of acute respiratory failure in older infants and children. Heating and humidification of gas mixtures allow comfortable delivery of flow rates that match or exceed the patient's inspiratory flow rate. Emerging evidence from observational studies suggests that the use of HHHFNC therapy may be associated with reduced work of breathing, improved ventilation efficiency and a decreased need for intubation in children with respiratory insufficiency. There are several proposed mechanisms of action, and the potential for provision of unpredictable positive distending pressure has caused concern. Randomised controlled trial evidence comparing clinical outcomes with those achieved using other forms of respiratory support is, however, awaited. We review the proposed mechanisms of actions, indications, advantages and complications of HHHFNC therapy in children and describe our approach to its use in the paediatric ward environment.

High-flow nasal cannula oxygen therapy in adults

High-flow nasal cannula (HFNC) oxygen therapy comprises an air/oxygen blender, an active humidifier, a single heated circuit, and a nasal cannula. It delivers adequately heated and humidified medical gas at up to 60 L/min of flow and is considered to have a number of physiological effects: reduction of anatomical dead space, PEEP effect, constant fraction of inspired oxygen, and good humidification. While there have been no big randomized clinical trials, it has been gaining attention as an innovative respiratory support for critically ill patients. Most of the available data has been published in the neonatal field. Evidence with critically ill adults are poor; however, physicians apply it to a variety of patients with diverse underlying diseases: hypoxemic respiratory failure, acute exacerbation of chronic obstructive pulmonary disease, post-extubation, pre-intubation oxygenation, sleep apnea, acute heart failure, patients with do-not-intubate order, and so on. Many published reports suggest that HFNC decreases breathing frequency and work of breathing and reduces needs of escalation of respiratory support in patients with diverse underlying diseases. Some important issues remain to be resolved, such as its indication, timing of starting and stopping HFNC, and escalating treatment. Despite these issues, HFNC oxygen therapy is an innovative and effective modality for the early treatment of adults with respiratory failure with diverse underlying diseases.

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.