High-flow Nasal Therapy Research Articles

Low-to-moderate dose corticosteroids treatment in hospitalized adults with COVID-19

ObjectivesUse of corticosteroids is common in the treatment of coronavirus disease 2019, but clinical effectiveness is controversial. We aimed to investigate the association of corticosteroids therapy with clinical outcomes of hospitalized COVID-19 patients. MethodsIn this single-centre, retrospective cohort study, adult patients with confirmed coronavirus disease 2019 and dead or discharged between 29 December 2019 and 15 February 2020 were studied; 1:1 propensity score matchings were performed between patients with or without corticosteroid treatment. A multivariable COX proportional hazards model was used to estimate the association between corticosteroid treatment and in-hospital mortality by taking corticosteroids as a time-varying covariate. ResultsAmong 646 patients, the in-hospital death rate was higher in 158 patients with corticosteroid administration (72/158, 45.6% vs. 56/488, 11.5%, p < 0.0001). After propensity score matching analysis, no significant differences were observed in in-hospital death between patients with and without corticosteroid treatment (47/124, 37.9% vs. 47/124, 37.9%, p 1.000). When patients received corticosteroids before they required nasal high-flow oxygen therapy or mechanical ventilation, the in-hospital death rate was lower than that in patients who were not administered corticosteroids (17/86, 19.8% vs. 26/86, 30.2%, log rank p 0.0102), whereas the time from admission to clinical improvement was longer (13 (IQR 10–17) days vs. 10 (IQR 8–13) days; p < 0.001). Using the Cox proportional hazards regression model accounting for time varying exposures in matched pairs, corticosteroid therapy was not associated with mortality difference (HR 0.98, 95% CI 0.93–1.03, p 0.4694). DiscussionCorticosteroids use in COVID-19 patients may not be associated with in-hospital mortality.

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

BackgroundIn 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.ObjectivesTo 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).MethodsTwelve 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.ResultsAt 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.ConclusionsIn 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.

Place des bronchodilatateurs inhalés et techniques d’administration sous assistance respiratoire

De nombreux médicaments bronchodilatateurs sont disponibles pour l’administration inhalée à l’aide de nébuliseurs ou d’aérosol doseurs. Les principales molécules évaluées dans le cadre de l’assistance ventilatoire sont le salbutamol et l’ipratropium qui ont une durée d’action courte. Les bronchodilatateurs sont fréquemment utilisés en réanimation principalement au cours du traitement des exacerbations aiguës des pathologies respiratoires obstructives chroniques, malgré l’absence d’un haut niveau de preuve concernant leur bénéfice sur des critères d’évaluation durs centrés sur les patients. Leur index thérapeutique est large c’est-à-dire qu’ils présentent une efficacité physiologique observée pour de faibles doses et une bonne tolérance, y compris pour des doses élevées. Néanmoins, certains effets indésirables principalement cardiovasculaires peuvent survenir malgré l’administration par voie pulmonaire. Leurs modalités d’administration sont différentes en fonction des modalités d’assistance ventilatoire, mais sont globalement simples que ce soit au cours de la ventilation non invasive, du haut débit nasal ou de la ventilation invasive, en raison de l’index thérapeutique large qui dispense de toute mesure d’optimisation. Au-delà de la surveillance clinique durant l’administration inhalée, la mise en place d’un filtre sur la branche expiratoire protégeant le ventilateur constitue un élément de sécurité important.

Measurement of airway pressure during high-flow nasal therapy in apnoeic oxygenation: a randomised controlled crossover trial.

It is recognised that high-flow nasal therapy can prevent desaturation during airway management. Studies in spontaneously breathing patients show an almost linear relationship between flow rate and positive airway pressure in the nasopharynx. Positive airway pressure has been suggested as one of the possible mechanisms explaining how high-flow nasal therapy works. However, data on pressures generated by high-flow nasal therapy in apnoeic adults under general anaesthesia are absent. This randomised controlled crossover trial investigated airway pressures generated by different flow rates during high-flow nasal therapy in anaesthetised and paralysed apnoeic patients, comparing pressures with closed and open mouths. Following induction of anaesthesia and neuromuscular blockade, a continuous jaw thrust was used to enable airway patency. Airway pressure was measured in the right main bronchus, the middle of the trachea and the pharynx, using a fibreoptically-placed catheter connected to a pressure transducer. Each measurement was randomised with respect to closed or open mouth and different flow rates. Twenty patients undergoing elective surgery were included (mean (SD) age 38 (18)years, BMI 25.0 (3.3) kg.m-2 , nine women, ASA physical status 1 (35%), 2 (55%), 3 (10%). While closed mouths and increasing flow rates demonstrated non-linear increases in pressure, the pressure increase was negligible with an open mouth. Airway pressures remained below 10cmH2 O even with closed mouths and flow rates up to 80l.min-1 ; they were not influenced by catheter position. This study shows an increase in airway pressures with closed mouths that depends on flow rate. The generated pressure is negligible with an open mouth. These data question positive airway pressure as an important mechanism for maintenance of oxygenation during apnoea.

Noninvasive Ventilation and High-Flow Nasal Therapy Administration in Chronic Obstructive Pulmonary Disease Exacerbations

Noninvasive ventilation (NIV) is considered to be the standard of care for the management of acute hypercapnic respiratory failure in patients with chronic obstructive pulmonary disease exacerbation. It can be delivered safely in any dedicated setting, from emergency rooms to high dependency or intensive care units and wards. NIV helps improving dyspnea and gas exchange, reduces the need for endotracheal intubation, and morbidity and mortality rates. It is therefore recognized as the gold standard in this condition. High-flow nasal therapy helps improving ventilatory efficiency and reducing the work of breathing in patients with severe chronic obstructive pulmonary disease. Early studies indicate that some patients with acute hypercapnic respiratory failure can be managed with high-flow nasal therapy, but more information is needed before specific recommendations for this therapy can be made. Therefore, high-flow nasal therapy use should be individualized in each particular situation and institution, taking into account resources, and local and personal experience with all respiratory support therapies.

Meta-trial of awake prone positioning with nasal high flow therapy: Invitation to join a pandemic collaborative research effort

• Awake prone positioning may improve patient's oxygenation and reduce the need for intubation. However, controlled evidence is lacking. • A meta-trial , with harmonized inclusion and outcome criteria and a global interim analysis plan, may quickly generate high level evidence. • Researchers are invited to join the “Meta-trial of awake prone positioning with nasal high flow therapy” : Awake.Prone.Meta.Trial@gmail.com

Histogram analysis for bedside respiratory monitoring in not critically ill preterm neonates: a proposal for a new way to look at the monitoring data.

Despite robust evidence in favour of maintaining optimal oxygen saturation targets in the preterm infants, the titration of oxygen is largely dependent on manual observations and transcription. Similarly, notwithstanding the gaining popularity of non-invasive modalities like high-flow nasal therapy, the practices of weaning and escalating support are largely individualized and based on point of care observations. These are often erroneous and lack objectivity. Histogram analysis from patient monitors is an easy and objective way of quantifying vital parameters and their trends. We review the technology and evidence available behind this practice.Conclusions: Though there are no randomized controlled trials on this practice solely, we identify several quality improvement studies implementing this into practice with benefit. We also cite studies which have implemented histogram analysis in methodology, thus concluding that this is a useful clinical tool worth incorporating into clinical practice to reduce manual errors and bring more objectivity into decisions.What is Known:• The data from NeOProM (Neonatal Oxygenation Prospective Meta-analysis Collaboration study protocol) indicates that optimal saturation targets for preterm infants born < 28 weeks should be between 91 and 95%.• The most “failsafe” way of maintaining strict compliance to these limits is automated oxygen titration but this is not widely used or available and manual transcription and monitoring are susceptible to error and fatigue.What is New:• Histogram analysis from patient monitors can provide intelligent data on respiratory monitoring and can be incorporated into algorithm to decide on weaning or escalation of respiratory support.• With appropriate training, histogram monitoring by nursing staff can limit fatigue of manual recording of data.

Role of Ultrasound-Guided Evaluation of Dyspnea in the Coronavirus Disease 2019 Pandemic

Role of Ultrasound-Guided Evaluation of Dyspnea in the Coronavirus Disease 2019 Pandemic

Efficacy of high-flow nasal prong therapy in trauma patients with rib fractures and high-risk features for respiratory deterioration: a randomized controlled trial

BackgroundPatients with rib fractures require analgesia, oxygen supplementation and physiotherapy. This combination has been shown to reduce morbidity and mortality due to rib fractures. There has been movement towards the...

Management of diagnostic procedures and treatment of sleep related breathing disorders in the context of the coronavirus pandemic

Bei der Erbringung schlafmedizinischer Leistungen im Zusammenhang mit der Corona-Pandemie sind besondere Aspekte zu berücksichtigen. Trotz aller vorbeugender Maßnahmen muss aufgrund der hohen Dunkelziffer mit SARS-CoV2-Kontakten im Schlaflabor gerechnet und entsprechende Vorkehrungen getroffen werden. Die Fortführung bzw. Wiederaufnahme schlafmedizinischer Leistungen unter den gebotenen Hygienemaßnahmen ist dennoch dringend anzustreben zur Vermeidung medizinischer und psychosozialer Komplikationen. Es gibt keine gesicherten Hinweise für eine Verschlechterung der COVID-19 durch eine CPAP-Therapie. Grundsätzlich kann die Anwendung einer Überdrucktherapie über verschiedene Maskensysteme mit der Bildung einer infektiösen Aerosolwolke einhergehen. Bei bestätigter Infektion mit SARS-CoV-2 sollte im ambulanten Umfeld eine vorbestehende Maskentherapie unter Einhaltung der Vorgaben des RKI zur häuslichen Isolierung fortgeführt werden, da eine Therapiebeendigung mit einer zusätzlichen kardiopulmonalen Belastung durch die unbehandelte schlafbezogene Atmungsstörung einhergeht. Mit geeigneter persönlicher Schutzausrüstung (Augenschutz, FFP2/FFP3-Maske, Kittel) kann eine PAP-Therapie nach jetzigem Kenntnisstand vom Personal ohne erhöhtes Infektionsrisiko durchgeführt werden.Dieses gemeinsame Positionspapier der Deutschen Gesellschaft für Pneumologie und Beatmungsmedizin (DGP) und der Deutschen Gesellschaft für Schlafmedizin (DGSM) beinhaltet konkrete Empfehlungen zur Durchführung schlafmedizinischer Diagnostik und Therapie im Umfeld der Corona-Pandemie.

Nasal high flow therapy introduction lowers reintubation risk in a Peruvian paediatric intensive care unit.

We examined the impact of introducing high-flow nasal oxygen therapy (HFNT) on children under five with post-extubation respiratory failure in a paediatric intensive care unit (PICU) in Peru. This quasi-experimental study compared clinical outcomes before and after initial HFNT deployment in the PICU at Instituto Nacional de Salud del Niño in Lima in June 2016. We compared three groups: 29 received post-extubation HFNT and 17 received continuous positive airway pressure (CPAP) from 2016-17 and 12 historical controls received CPAP from 2012-16. The primary outcome was the need for mechanical ventilation. Adjusted hazard ratios (aHR) and 95% confidence intervals (95% CI) were calculated via survival analysis. High-flow nasal oxygen therapy and CPAP did not alter the need for mechanical ventilation after extubation (aHR 0.47, 95% CI 0.15-1.48 and 0.96, 95% CI 0.35-2.62, respectively) but did reduce the risk of reintubation (aHR 0.18, 95% CI 0.06-0.57 and 0.14, 95% CI 0.03-0.72, respectively). PICU length of stay was 11, 18 and 37days for CPAP, HFNT and historical CPAP and mortality was 12%, 7% and 27%, respectively. There was no effect on the duration of sedative infusions. High-flow nasal oxygen therapy provided effective support for some children, but larger studies in resource-constrained settings are needed.

Effect of high-flow nasal therapy during early pulmonary rehabilitation in patients with severe AECOPD: a randomized controlled study

BackgroundChronic obstructive pulmonary disease (COPD) is airway inflammation characterized and low daily physical activity. Most pulmonary rehabilitation (PR) programs are often provided to stable patients, but fewer training programs are specific for hospitalized patients with acute exacerbation (AE). Patients with AECOPD experience increased dyspnea sensations and systemic inflammation during exercise training. High-flow nasal therapy (HFNT) reduces the minute volume, lowers the respiratory rate, and decreases the work of breathing. However, it is not clear whether HFNT is efficient during exercise training. In this study, we investigated the effects of HFNT during exercise training in an early PR program among hospitalized patients with severe AECOPD.MethodsWe enrolled COPD patients hospitalized due to AE. They were randomized into two groups according to their status into HFNT PR and non-HFNT PR groups. This study collected basic data, and also assessed a pulmonary function test, 6-min walking test, blood inflammatory biomarkers, and arterial gas analysis at the baseline, and at 4 and 12 weeks of the intervention. Data were analyzed using SPSS statistical software.ResultWe recruited 44 AECOPD patients who completed the 12-week PR program. The HFNT PR program produced significant improvements in exercise tolerance as assessed by the 6-min walking distance (6MWD), reduced dyspnea sensations in the modified Medical Research Council (mMRC), and decreased systemic inflammation as evidenced by the a lower C-reactive protein (CRP) level. A reduction in the length of hospitalization was achieved with PR in the 1-year follow-up in the two groups. The HFNT PR group showed better trends of reduced air trapping in the delta inspiration capacity (IC) and an increased quality of life according to the COPD assessment test (CAT) than did the non-HFNT PR group.ConclusionsHFNT during exercise training in early PR increases exercise tolerance and reduces systemic inflammation in hospitalized patients with severe AECOPD.

Nonintubated uniportal thoracoscopic segmentectomy for lung cancer

Uniportal thoracoscopic segmentectomy under intubated general anesthesia with one-lung ventilation has recently been introduced for the management of lung cancer patients with small tumors or compromised cardiopulmonary function. However, uniportal thoracoscopic segmentectomy without endotracheal intubation had rarely been performed. Therefore, in this study, we aimed to evaluate the feasibility and safety of this novel technique. From January 2014 to November 2018, 32 lung cancer patients were treated using nonintubated uniportal thoracoscopic segmentectomy under a combination of target-controlled infusion of propofol, nasal high-flow oxygen therapy, intrathoracic intercostal nerve blockade, and vagal nerve blockade. Sixty-two other lung cancer patients who underwent initial planning nonintubated multiportal thoracoscopic segmentectomy during the same period were included as the control group. Preoperative dye localization was required in 18 (56.3%) patients of uniportal group. No patients required conversion to tracheal intubation or thoracotomy. Two patients were converted from the one-port to the two-port approach due to severe adhesions in the pleural cavity. The mean durations of anesthetic induction and surgery were 12.7min and 101.1min, respectively. Postoperative complications were noted in two patients (2/32, 6.3%) of uniportal group: one had subcutaneous emphysema and the other had prolonged air leaks over 3 days. The median durations of postoperative chest drainage and hospital stay were 1 and 3 days in uniportal group, respectively. Nonintubated uniportal thoracoscopic segmentectomy is technically feasible and safe for selected patients. It can be an attractive alternative to intubated thoracoscopic segmentectomy for patients with early lung cancer.

SARS-CoV-2 in Spanish Intensive Care Units: Early experience with 15-day survival in Vitoria

PurposeCommunity transmission of SARS-CoV-2 was detected in Spain in February 2020, with 216% intensive care unit (ICU) capacity expanded in Vitoria by March 18th, 2020. MethodsWe identified patients from the two public hospitals in Vitoria who were admitted to ICU with confirmed infection by SARS-CoV-2. Data reported here were available in April 6th, 2020. Mortality was assessed in those who completed 15-days of ICU stay. ResultsWe identified 48 patients (27 males) with confirmed SARS-CoV-2. Median [interquartile range (IQR)] age of patients was 63 [51–75] years. Symptoms began a median of 7 [5–12] days before ICU admission. The most common comorbidities identified were obesity (48%), arterial hypertension (44%) and chronic lung disease (37%). All patients were admitted by hypoxemic respiratory failure and none received non-invasive mechanical ventilation. Forty-five (94%) underwent intubation, 3 (6%) high flow nasal therapy (HFNT), 1 (2%) extracorporeal membrane oxygenation (ECMO) and 22 (46%) required prone position. After 15 days, 14/45 (31%) intubated patients died (13% within one week), 10/45 (22%) were extubated, and 21/45 (47%) underwent mechanical ventilation. Six patients had documented super-infection. Procalcitonin plasma above 0.5μg/L was associated with 16% vs. 19% (p=0.78) risk of death after 7 days. ConclusionThis early experience with SARS-CoV-2 in Spain suggests that a strategy of right oxygenation avoiding non-invasive mechanical ventilation was life-saving. Seven-day mortality in SARS-CoV-2 requiring intubation was lower than 15%, with 80% of patients still requiring mechanical ventilation. After 15 days of ICU admission, half of patients remained intubated, whereas one third died.

Analysis of early predictive factors for invalidity of high flow nasal catheter oxygen therapy

Objective High-flow nasal cannula (HFNC) is a new method to treat adult respiratory distress. This study aims to explore the early predictors of the inefficiency of HFNC in patients with respiratory distress. Methods A total of 162 patients with respiratory distress were treated with HFNC oxygen therapy in the Department of Respiratory and Critical Care Medicine, Emergency and Critical Care Medicine. The age, sex, weight, history, diagnosis, vital signs, blood oxygen saturation/inhaled oxygen concentration (SpO2/FiO2, SF) ratio, and modified respiratory distress score (mRDAI) , duration of HFNC oxygen therapy, replacement of advanced oxygen therapy support time, adverse reactions and other data were extracted from the medical electronic medical records. Results A total of 154 valid samples were included, with a median age of 55 (inter-quartile range 47-72), including 59 patients (38.3%) with acute bronchiolitis, 64 patients (41.6%) with bacterial pneumonia, 31 patients (20.1%) with atypical or viral pneumonia; 129 patients (83.8%) with effective HFNC oxygen therapy and 25 patients (16.2%) with ineffective HFNC oxygen therapy. SF ratio in ineffective HFNC oxygen therapy patients at admission was lower, pH value was lower, partial pressure of carbon dioxide was higher (P values were 0.008, 0.012, 0.001). RR, mRDAI score and SF ratio in the first hour of effective HFNC oxygen therapy patients improved significantly (t values were 1.732, 9.783, 37.591, P<0.05 or 0.01). SF ratio in the first hour of HFNC was lower than 195 (area under curve 0.842, 95%CI 0.743-0.942, P<0.01). It was the critical value for the ineffectiveness of oxygen therapy. Conclusions When patients with respiratory distress are supported by HFNC oxygen therapy, the lower initial fingertip oxygen saturation, higher blood gas arterial partial pressure of carbon dioxide and lower SF ratio are the early predictors of failure of HFNC oxygen therapy. Key words: Respiratory distress; High flow oxygen therapy; Blood oxygen saturation/inhaled oxygen concentration ratio; Predictors

Transnasal high flow oxygen therapy combined with noninvasive positive pressure ventilation Chronic obstructive pulmonary disease with respiratory failure patient outcomes

Objective To investigate the effect of Nasal high-flow oxygen therapy combined with noninvasive positive pressure ventilation on COPD patients with respiratory failure and the effects on the levels of PaO2, PaCO2 and SaO2. Methods A total of 126 patients with COPD complicated with respiratory failure who were admitted from January 2017 to June 2019, including 69 males and 57 females, aged(58.94±5.89)years and ranging in age from 45 to 76 years, were randomly divided into NPPV group and HFNC group by random number table method, with 63 cases in each group.Patients in the NPPV group were given NPPV, while HFNC group was given HFNC on the basis of NPPV group.The clinical treatment effect and complications of the two groups were compared 48 h after treatment, and the changes in blood oxygen partial pressure, blood carbon dioxide partial pressure, blood oxygen saturation level, heart rate, respiratory rate and sputum viscosity of the two groups before and after treatment were compared. Results After treatment, the effective rate of HFNC group[95.2%(60/63)]was higher than that of NPPV group[82.6%(52/63)]. HFNC group had higher blood oxygen partial pressure[(87.87±9.45)mmHg, 1 mmHg=0.133 kPa]and blood oxygen saturation[(89.29±8.99)%]than NPPV group[(78.43±8.69)mmHg and(82.21±8.20)%], and lower blood carbon dioxide partial pressure[(47.95±4.85)mmHg]than NPPV group[(56.72±5.19)mmHg]. HFNC group had lower heart rate[(85.45±4.38)times/minute]and respiratory rate[(18.39±2.03)times/minute]than NPPV group[(92.87±4.72)times/minute, [22.49±2.52)times/minute]than NPPV group, with statistically significant differences(P<0.05). Conclusion HFNC combined with NPPV in the treatment of COPD patients with respiratory failure has a good clinical treatment effect, which can improve the levels of PaO2, PaCO2 and SaO2 and reduce the viscosity of sputum, which is worthy of clinical application. Key words: Nasal high-flow oxygen therapy; Noninvasive positive pressure ventilation; COPD combined with respiratory failure; PaO2; PaCO2; Oxygen saturation

High Flow Nasal Therapy Use in Patients with Acute Exacerbation of COPD and Bronchiectasis: A Feasibility Study

The efficacy and feasibility of high flow nasal therapy (HFNT) use in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and bronchiectasis is unknown. We performed a single-center, single-arm prospective observational study in patients with AECOPD, documented bronchiectasis, pH ≥ 7.35, respiratory rate (RR) ≥ 26 breaths/minute despite receiving maximal medical treatment and oxygen via face mask up to 10 L/m. Patients received HFNT (Airvo 2, Fisher & Paykel) at a gas flow of 50 L/min and FIO2 adjusted to maintain SpO2 ≥92%. Dyspnea, rated by Borg scale, RR, arterial blood gases and mucus production (ranging from 1 to 3) were collected before and 1 h after starting HFNT and then every 24 h for 3 days. Tolerance was measured using a visual analogic scale (VAS). Fifteen patients were enrolled. After 24 h, patients showed a significant improvement in dyspnea score [Borg scale from 6.7 ± 1.4 to 4.1 ± 1.3 (p<.001)]; RR decreased from 29.6 ± 2.7 breaths/min to 23.2 ± 2.9 breaths/min (p<.001); pCO2 significantly decreased after 24 h [58.4 ± 13 vs. 51.7 ± 8.2 (p=.003)] while quantity of mucus production increased [(1.1 ± 0,6 vs. 2.4 ± 0.7, p<.001)]. No patient received invasive or noninvasive mechanical ventilation. Overall VAS score for HFNT tolerance was 6.5. HFNT was effective in improving dyspnea score, decreasing RR, improving gas exchange, and increasing mucus production in patients with AECOPD and coexisting bronchiectasis. Moreover, no safety concerns on its use were detected. Nevertheless, due to the single-arm design, the effect of HFNT could not be isolated from standard pharmacological treatment due to the study design.

Mechanisms of nasal high flow therapy in newborns.

In newborns, it is unclear how nasal high flow (NHF) generates positive airway pressure. In addition, the reported benefits of NHF such as reduction in work of breathing may be independent of airway pressure. The authors hypothesized that during NHF the area of leak and the flow determine airway pressure and that NHF can reduce the required minute ventilation to maintain gas exchange. In response to NHF, pressure was measured in the upper airways of 9 newborns and ventilation was measured in another group of 17 newborns. In a bench model, airway pressures were measured during NHF with different prong sizes, nare sizes, and flows. The airway pressures during 8 L/min NHF were greater when a larger cannula versus a smaller cannula was used (P < 0.05). NHF reduced minute ventilation in 16 of 17 neonates, with a mean decrease of 24% from a baseline of 0.66 L/min (SD 0.21) (P < 0.001), and was unrelated to changes in airway pressure; arterial oxygen saturation by pulse oximetry () and tissue CO2 were unchanged. In the bench model, the airway pressure remained <2 cmH2O when <50% of the “nare” was occluded by the prongs. As the leak area decreased, because of a smaller nare or a larger cannula, the airway pressure increased exponentially and was dependent on flow. In newborns NHF using room air substantially reduced minute ventilation without affecting gas exchange irrespective of a decrease or an increase of respiratory rate. NHF generates low positive airway pressure that exponentially increases with flow and occlusion of the nares.NEW & NOTEWORTHY In healthy newborns, nasal high flow (NHF) with room air reduced minute ventilation by one-fourth without affecting gas exchange but, in contrast to adults, produced variable response in respiratory rate during sleep. During NHF, pressure in the upper airways did not exceed 2 cmH2O at 8 L/min (3.4 L·min−1·kg−1) and was unaffected by opening of the mouth. NHF can generate higher pressure with larger prongs that decrease the leak around the cannula or by increasing the flow rate.

Enteral hydration in high-flow therapy for infants with bronchiolitis: Secondary analysis of a randomised trial.

Nasal high-flow oxygen therapy is increasingly used in infants for supportive respiratory therapy in bronchiolitis. It is unclear whether enteral hydration is safe in children receiving high-flow. We performed a planned secondary analysis of a multi-centre, randomised controlled trial of infants aged <12 months with bronchiolitis and an oxygen requirement. Children were assigned to treatment with either high-flow or standard-oxygen therapy with optional rescue high-flow. We assessed adverse events based on how children on high-flow were hydrated: intravenously (IV), via bolus or continuous nasogastric tube (NGT) or orally. A total of 505 patients on high-flow via primary study assignment (n = 408), primary treatment (n = 10) or as rescue therapy (n = 87) were assessed. While on high flow, 15 of 505 (3.0%) received only IV fluids, 360 (71.3%) received only enteral fluids and 93 (18.4%) received both IV and enteral fluids. The route was unknown in 37 (7.3%). Of the 453 high-flow infants hydrated enterally patients could receive one or more methods of hydration; 80 (15.8%) received NGT bolus, 217 (43.0%) NGT continuous, 118 (23.4%) both bolus and continuous, 32 (6.3%) received only oral hydration and 171 (33.9%) a mix of NGT and oral hydration. None of the patients receiving oral or NGT hydration on high-flow sustained pulmonary aspiration (0%; 95% confidence interval N/A); one patient had a pneumothorax (0.2%; 95% confidence interval 0.0-0.7%). The vast majority of children with hypoxic respiratory failure in bronchiolitis can be safely hydrated enterally during the period when they receive high-flow.

Application of high-flow nasal humidified oxygen therapy in patients with hypercapnic respiratory failure

Hypercapnia respiratory failure is one of the common types of respiratory failure in clinical practice. Traditional oxygen therapy can improve oxygenation, but may inevitable cause some complications. In recent years, high-flow nasal humidified oxygen (HFNC) therapy has been widely used in clinical setting as a new effective method. It uses high speed of oxygen flow to reduce the anatomical dead space of the mouth, nose and pharynx, reduce CO2 re-inspiration, produce positive pressure at the end of exhalation, increase expiratory lung volume and become the ideal choice of patients with high carbonate type of respiratory failure. This paper reviews the application of HFNC therapy in hypercapnic respiratory failure in recent years. Key words: High-flow nasal humidified oxygen therapy; Respiratory failure; Hypercapnia