"Comparison between high-flow nasal cannula (HFNC) therapy and noninvasive ventilation (NIV) in children with acute respiratory failure by bronchiolitis: a randomized controlled trial".

BACKGROUND: The objective of this study was to compare HFNC therapy to noninvasive ventilation (NIV/BiPAP) in children with bronchiolitis who developed respiratory failure. We hypothesized that HFNC therapy would not be inferior to NIV. METHODS: This was a noninferiority open-label randomized single-center clinical trial conducted at a tertiary Brazilian hospital. Children under 2 years of age with no chronic conditions admitted for bronchiolitis that progressed to mild to moderate respiratory distress (Wood-Downes-Férres score < 8) were randomized to either the HFNC group or NIV (BiPAP) group through sealed envelopes. Vital signs, FiO2, Wood-Downes-Férres score and HFNC/NIV parameters were recorded up to 96 h after therapy initiation. Children who developed respiratory failure despite receiving initial therapy were intubated. Crossover was not allowed. The primary outcome analyzed was invasive mechanical ventilation requirement. The secondary outcomes were sedation usage, invasive mechanical ventilation duration, the PICU LOS, the hospital LOS, and mortality rate. RESULTS: A total of 126 patients were allocated to the NIV group (132 randomized and 6 excluded), and 126 were allocated to the HFNC group (136 randomized and 10 excluded). The median age was 2.5 (1-6) months in the NIV group and 3 (2-7) months in the HFNC group (p = 0,07). RSV was the most common virus isolated in both groups (72% vs. 71.4%, NIV and HFNC, respectively). Thirty-seven patients were intubated in the NIV group and 29 were intubated in the HFNC group (29% vs. 23%, p = 0.25). According to the Farrington-Manning test, with a noninferiority margin of 15%, the difference was 6.3% in favor of HFNC therapy (95% confidence interval: -4.5 to 17.1%, p < 0.0001). There was no significant difference in the PICU LOS or sedation duration. Sedation requirement, hospital LOS and invasive mechanical ventilation duration were lower in the HFNC group. CONCLUSION: HFNC therapy is noninferior to NIV in infants admitted with mild to moderate respiratory distress caused by bronchiolitis that progresses to respiratory failure. TRIAL REGISTRATION NUMBERS: U1111-1262-1740; RBR-104z966s. Registered 03/01/2023 (retrospectively registered). ReBEC: https://ensaiosclinicos.gov.br/rg/RBR-104z966s .

Combined awake videolaryngo-bronchoscopy intubation with HFNC preoxygenation for predicted difficult airway in a patient with post-burn mentosternal scar contracture.

Airway management and safety remain a difficult challenge during reconstructive surgery in patients with extensive post-burn mentosternal scar contractures. Current guidelines do not recommend the use of direct laryngoscopy for predicted difficult airway because of the risk of intubation failure and airway emergencies: the consequences of wrong decisions can be fatal, and the patient is at serious risk. At present, video-laryngoscopy is the most commonly used technique for routine orotracheal intubation. Awake tracheal intubation with fibro-bronchoscopy also remains a valid option when possible, ensuring the patient's spontaneous breathing during the procedure. However, when videolaryngoscopy is used in combination with this method, the efficiency of these devices can be increased, and a better result can be achieved. We report a case of successful management of a predicted difficult airway with combined video laryngo-bronchoscopy in an awake patient with post-burn neck scar contractures.

Central Hypercapnia in a Neonate With Parechovirus Infection.

Human parechovirus infections in newborns often affect the central nervous system. It is common in children after infancy for it to be a cause of the common cold or be asymptomatic, but an infection in infancy often causes a central nervous system infection. Herein, we present the case of a nine-day-old infant who developed hypercapnia without any involvement of respiratory lesions. She showed no hypoxia or circulatory abnormalities. A high-flow nasal cannula relieved hypercapnia and consequent respiratory acidosis, suggesting that the hypercapnia was due to central ventilation failure with central nervous system infection despite no abnormalities on brain magnetic resonance imaging. Accurate diagnosis and intervention of ventilatory failure, which is a central nervous system dysfunction, is important in hypercapnia associated with parechovirus infection.

The starting temperature of high-flow nasal cannula and perceived comfort in critically ill patients: A pragmatic randomized controlled trial.

BACKGROUND: High-flow nasal cannula (HFNC) therapy is a non-invasive respiratory treatment characterized by high tolerability, which largely derives from the patient's comfort. AIMS: The primary aim of this study was to explore whether the patient's perceived comfort was the same regardless of different approaches used to reach the target humidification temperature. The secondary aim was to assess the patient's perceived nasal dryness and humidity. STUDY DESIGN: This single-centre, pragmatic, randomized trial was registered at clinicaltrials.gov (NCT05688189). Patients in the intensive care unit (ICU) in need of HFNC therapy were randomly assigned to one of three study arms: a two-step increase (31 to 34 to 37°C), a one-step increase in temperature (34-37°C) or no temperature increase (started and remained at 37°C). The patients were asked to rate their perceived comfort, as well as their perceived nasal dryness and humidity on a scale from 1 (lowest value) to 5 (highest value). RESULTS: We enrolled 21 patients, aged 34-85 years. The mean (±1 standard deviation) comfort level was 3.3 (1.3) for patients who received a one-step increase, 3.1 (1.3) for those who received no increase and 2.7 (1.7) for those who received a two-step increase (p = .714). There was also no difference in nasal dryness (p = .05) or humidity (p = .612) across the study arms. Greater comfort was fairly correlated with less nasal humidity (ρ = -0.34, 95% confidence interval -0.68 to 0.07) but not with nasal dryness (ρ = 0.01, p = .94). CONCLUSIONS: After 30 min of HFNC therapy at a target temperature of 37°C, overall comfort was rated similarly in the three study arms. Additional studies are needed to accumulate evidence corroborating the findings of this study. RELEVANCE TO CLINICAL PRACTICE: The temperature of the mixture of air and oxygen is a fundamental component of HFNC therapy. A pragmatic approach irrespective of the initial temperature setting seems to yield a similar comfort score in hospitalized patients with mild respiratory failure because of extrapulmonary causes.

Cadaveric Study on the Safety of High-Flow Nasal Oxygen in Laser Microlaryngeal Surgery.

INTRODUCTION: High-flow nasal oxygen (HFNO), or transnasal humidified rapid-insufflation ventilatory exchange (THRIVE), is a technique providing apneic oxygenation and a degree of ventilation during microlaryngeal surgery. Its use with laser has been questioned due to concern for airway fire. For fire to occur, a triad of ignition source, oxidizer, and fuel source must be present. By using HFNO and eliminating an endotracheal tube (fuel source), it is hypothesized that airway fire risk is minimal. We tested this theory with human cadavers using HFNO with increasing levels of FiO2 while performing microlaryngeal laser surgery. METHODS: HFNO was placed on two cadavers, and oxygen was administered at incrementally increasing fraction of inspired oxygen (FiO2) concentrations (30%-100%). Laryngeal microsurgery was conducted with CO2 and KTP lasers applied for 30 s. Oxygen readings were taken at several anatomic locations along the body assessing oxygen concentrations in correlation with increasing FiO2 administration. RESULTS: The use of CO2 and KTP laser on cadaveric vocal folds produced char but no spark or airway fire at any of the tested oxygen concentrations. Apart from the mouth, there was minimal increase in oxygen levels at the surrounding anatomic sites despite elevating FiO2 levels. CONCLUSION: HFNO may be safe to use during microlaryngeal laser surgery. By eliminating the endotracheal tube as a fuel source, risk of airway fire may be negligible. Our study safely applied CO2 and KTP lasers for an uninterrupted 30 s with HFNO at 70 L/min and 100% FiO2 producing no spark or fire. LEVEL OF EVIDENCE: NA Laryngoscope, 2024.

A Comprehensive Review on High-Flow Nasal Cannula Oxygen Therapy in Critical Care: Evidence-Based Insights and Future Directions.

High-flow nasal cannula (HFNC) therapy has emerged as a significant advancement in respiratory support, offering a non-invasive alternative to traditional oxygen delivery methods in critical care settings. This review comprehensively evaluates HFNC therapy, focusing on its definition, historical evolution, and current clinical applications. HFNC therapy delivers humidified and heated oxygen at high flow rates through a nasal cannula, enhancing oxygenation and patient comfort. The review highlights the physiological mechanisms underlying HFNC and its efficacy in managing acute respiratory failure, chronic obstructive pulmonary disease exacerbations, and postoperative respiratory support. Key findings from clinical trials and meta-analyses are discussed, emphasizing HFNC's advantages over conventional methods, such as reduced intubation rates and shorter ICU stays. The review also addresses safety considerations, including potential risks and complications associated with HFNC therapy. Furthermore, it explores future directions for research and technological advancements aimed at optimizing HFNC use in diverse patient populations. This review aims to provide evidence-based insights to inform clinical practice and guide future investigations in respiratory therapy.

Oxygen Delivery Devices in Postoperative Patients: Proper Selection of Patients Matters!

How to cite this article: Bhattacharya D, Esquinas AM, Mandal M. Oxygen Delivery Devices in Postoperative Patients: Proper Selection of Patients Matters! Indian J Crit Care Med 2024;28(8):802.

Effect on post-operative pulmonary complications frequency of high flow nasal oxygen versus standard oxygen therapy in patients undergoing esophagectomy for cancer: study protocol for a randomized controlled trial-OSSIGENA study.

Background: Postoperative pulmonary complications (PPCs) remain a challenge after esophagectomy. Despite improvement in surgical and anesthesiological management, PPCs are reported in as many as 40% of patients. The main aim of this study is to investigate whether early application of high-flow nasal cannula (HFNC) after extubation will provide benefit in terms of reduced PPC frequency compared to standard oxygen therapy. Methods: Patients aged 18-85 years undergoing esophagectomy for cancer treatment with radical intent, excluding those with American Society of Anesthesiologists (ASA) score >3 and severe systemic comorbidity (cardiac, pulmonary, renal or hepatic disease) will be randomized at the end of surgery to receive HFNC or standard oxygen therapy (Venturi mask or nasal goggles) after early extubation (within 12 hours after the end of surgery) for 48 hours. The main postoperative goals are to obtain SpO2 ≥94% and adequate pain control. Oxygen therapy after 48 hours will be stopped unless the physician deems it necessary. In case of respiratory clinical worsening, patients will be supported with the most appropriate tool (noninvasive ventilation or invasive mechanical ventilation). Pulmonary [pneumonia, pleural effusion, pneumothorax, atelectasis, acute respiratory distress syndrome (ARDS), tracheo-bronchial injury, air leak, reintubation, and/or respiratory failure] complications will be recorded as main outcome. Secondary outcomes, including cardiovascular, surgical, renal and infective complications will also be recorded. The primary analysis will be carried out on 320 patients (160 per group) and performed on an intention-to-treat (ITT) basis, including all participants randomized into the treatment groups, regardless of protocol adherence. The primary outcome, the PPC rate, will be compared between the two treatment groups using a chi-square test for categorical data, or Fisher's exact test will be used if the assumptions for the chi-square test are not met. Discussion: Recent evidence demonstrated that early application of HFNC improved the respiratory rate oxygenation index (ROX index) after esophagectomy but did not reduce PPCs. This randomized controlled multicenter trial aims to assess the potential effect of the application of HFNC versus standard oxygen over PPCs in patients undergoing esophagectomy. Trial Registration: This study is registered at clinicaltrial.gov NCT05718284, dated 30 January 2023.

Predictors of high-flow nasal cannula failure in COVID-19 patients in a northern Peruvian hospital.

OBJECTIVES: To determine predictors of high-flow nasal cannula (HFNC) failure in COVID-19 patients in a hospital in northern Peru. METHODOLOGY: A retrospective cohort study was conducted during the months of March and May 2021. Data collection was based on a follow-up of 156 hospitalized patients with a diagnosis of COVID-19 who were users of HFNC. Epidemiological factors and clinical outcomes of treatment were analyzed from medical records. Epidemiological, analytical, and HFNC use-related characteristics were described using measures of absolute and relative frequencies, measures of central tendency, and dispersion. A multivariate Poisson regression analysis with robust variance and a 95% confidence interval was performed. RESULTS: We found that age, SpO2/FiO2, work of breathing (WOB scale) at admission, degree of involvement, type of infiltrate on CT scan, lymphocytes, c-reactive protein, and D-dimer were significantly associated with failure of HFNC (p < 0.05). In addition, the WOB scale, PaO2/FiO2, SaO2/FiO2, and ROX index were variables that presented statistical significance (p < 0.0001). In the multivariate analysis model, a risk of failure of HFNC was determined with age > = 60 years [RRa 1.39 (1.05-1.85)] and PaO2/FiO2 score less than 100 [Rra 1.65 (0.99-2.76)]. CONCLUSIONS: Predictors to failure of HFNC are age older than 60 years and minimally significantly lower PaO2/FiO2 than 100.

Evaluating Pressure Variability and Influencing Factors during High-Flow Nasal Cannula Therapy in Premature Infants.

BACKGROUND: Heated humidified high-flow nasal cannulas (HHHFNCs) are increasingly used as an alternative strategy for weaning from nasal continuous positive airway pressure (NCPAP) in premature infants. However, the optimal pressure provided by HHHFNCs is unknown. This retrospective study investigated the pressure changes and associated factors during HHHFNC therapy in preterm infants. METHODS: Clinically stable preterm neonates born with a birth weight of 2500 g or less and receiving HHHFNC therapy for weaning from NCPAP were enrolled. The flow of the HHHNFCs was adjusted to achieve an initial pressure equivalent to the positive expiratory pressure (PEEP) of NCPAP. Subsequent pressure changes in the HHHFNCs were measured by a GiO digital pressure gauge. RESULTS: Nine premature infants were enrolled. Their gestational age (mean ± SD) was 28.33 ± 2.61 weeks, and the birth weight was 1102.00 ± 327.53 g. Overall, 437 pressure measurements were conducted. The median pressure of the HHHFNCs was 5 cmH2O. The generated pressure had a significant association with the body weight, postmenstrual age (PMA) and flow rate. A multiple regression model revealed that the measured pressure (cmH2O) = -5.769 + 1.021 × flow rate (L/min) - 0.797 × body weight (kg) + 0.035 × PMA (days) (r2 = 0.37, p < 0.001). CONCLUSIONS: The pressure provided by HHHFNCs is influenced by body weight, PMA, and flow rate. It is feasible to set the delivered pressure of HHHFNCs to match the applied PEEP of NCPAP initially, facilitating the weaning of preterm infants from NCPAP to HHHFNCs.

Dos and don'ts to optimize transnasal aerosol drug delivery in clinical practice.

INTRODUCTION: Transnasal aerosol drug delivery has become widely accepted for treating acutely ill infants, children, and adults. More recently aerosol administration to wider populations receiving high and low-flow nasal oxygen has become common practice. AREAS COVERED: Skepticism of insufficient aerosol delivery to the lungs has been tempered by multiple in vitro explorations of variables to optimize delivery efficiency. Additionally, clinical studies demonstrated comparable clinical responses to orally inhaled aerosols. This paper provides essential clinical guidance on how to improve transnasal aerosol delivery based on device-, settings-, and drug-related optimization to serve as a resource for educational initiatives and quality enhancement endeavors at healthcare institutions. EXPERT OPINION: Transnasal aerosol delivery is proliferating worldwide, but indiscriminate use of excessive-high flows, poor selection and placement of aerosol devices and circuits can greatly reduce aerosol delivery and efficacy, potentially compromising treatment to acute and critically ill patients. Attention to these details can improve inhaled dose by an order of magnitude, making the difference between effective treatment and the progression to more invasive ventilatory support, with greater inherent risk and cost. These revelations have prompted specific recommendations for optimal delivery, driving advancements in aerosol generators, formulations, and future device designs to administer aerosols and maximize treatment effectiveness.

Clinical Characteristics and Risk Factors of Mechanical Ventilation Among COVID-19 Patients on High-Flow Nasal Oxygen (HFNO).

INTRODUCTION: COVID-19 is a viral infection affecting the respiratory system, primarily. It has spread globally ever since it first appeared in China in 2019. The use of high-flow nasal oxygen (HFNO) for the treatment of COVID-19 has not been well established. OBJECTIVES: The primary objectives of this study are to observe the success of HFNO in preventing escalation to mechanical ventilation (MV) and to measure the prevalence of HFNO in King Abdulaziz Medical City (KAMC). The secondary objective is to describe patients who received HFNO clinically. METHODS: This is a retrospective cohort study of all polymerase chain reaction (PCR)-confirmed COVID-19 patients who require oxygen therapy in KAMC, Jeddah between March 1st, 2020, and December 31st, 2020. Any patients requiring MV on admission were excluded. RESULTS: 259 patients fit the inclusion criteria, and 25.5% of those included received HFNO. The number of non-survivors is 47 (18.1%). Mortality for HFNO, MV, and intensive care unit (ICU) are 30 (45.5%), 31 (60.8%), and 24 (32%), respectively. Their demographic was as follows; 160 were males, with a mean age of 60.93±15.01. Regarding the types of oxygen, low-flow nasal oxygen (LFNO) was administered to 243 out of the 259 patients, 66 received HFNO, 42 received MV, and 49 received other modes of ventilation. Additionally, 43.9% received HFNO escalated to MV. Patients who did not receive HFNO or MV were 178 (68.7%) in total. CONCLUSION: The use of HFNO in COVID-19 patients could show better outcomes than MV in addition to preventing the use of MV. Larger studies are required to determine the efficacy of HFNO in COVID-19 patients.

Sedation for GI Endoscopy in the Morbidly Obese: Challenges and Possible Solutions.

With the increasing prevalence of obesity and morbid obesity, this subgroup's contribution to patients presenting for elective procedures requiring sedation is significant. Gastrointestinal (GI) procedures clearly form the largest group of such procedures. These procedures may be intended to treat obesity such as the insertion of an intragastric balloon or one or more unrelated procedures such as a screening colonoscopy and (or) diagnostic/therapeutic endoscopy. Regardless of the procedure, these patients pose significant challenges in terms of choice of sedatives, dosing, airway management, ventilation, and oxygenation. An understanding of dissimilarity in the handling of different groups of medications used by an anesthesia provider and alterations in airway anatomy is critical for providing safe sedation. Administration of sedative medications and conduct of anesthesia requires dose modifications and airway adjuncts. In this review, we discuss the above issues in detail, with a particular focus on GI endoscopy.

High Flow Nasal Cannula Versus Conventional Oxygen Therapy and Incidence of Post-Extubation Airway Obstruction in PICU: An Open-Label Randomized Controlled Trial (HiFloCOT-PICU Trial).

OBJECTIVES: To study the impact of high flow nasal cannula (HFNC) vs. conventional oxygen therapy (COT) (by simple nasal cannula) as respiratory support after extubation on the rates of post-extubation airway obstruction (PEAO) among mechanically ventilated critically ill children. METHODS: This open-label randomized controlled trial was conducted in pediatric intensive care unit (PICU) of a tertiary care teaching hospital in North India over a period of 7 mo (11 August 2021 to 10 March 2022). Children aged 3 mo to 12 y who required invasive mechanical ventilation for > 72 h and had passed spontaneous breathing trial (ready for extubation) were enrolled and randomized by computer generated block randomization to receive HFNC or COT after extubation. Primary outcome was rate of PEAO (assessed by modified Westley croup score, mWCS) within 48 h of extubation; and secondary outcomes were rate and number of adrenaline nebulization, treatment failure (requiring escalation of respiratory support), extubation failure, adverse events, and length of PICU stay in two groups. RESULTS: During the study period, 116 children were enrolled (58 each in HFNC and COT groups). There was no difference in rate of PEAO (55% vs. 51.7%, respectively), need of adrenaline nebulization, extubation failure, adverse events, and duration of PICU stay in two groups. However, the HFNC group had significantly lower rates of treatment failure (27.6% vs. 48.3%, p = 0.02). CONCLUSIONS: The rate of PEAO was similar in HFNC and COT groups. However, HFNC group had significantly lower rate of treatment failure requiring escalation of respiratory support.

High-Flow Nasal Cannula and in-line aerosolised bronchodilator delivery during severe exacerbation of asthma in adults: A feasibility Observational Study.

BACKGROUND: Asthma is a common chronic respiratory disease affecting 1-29% of the population in different countries. Exacerbations represent a change in symptoms and lung function from the patient's usual condition that requires emergency department (ED) admission. Recently, the use of a High-Flow Nasal Cannula (HFNC) plus an in-line vibrating mesh nebulizer (VMN) for aerosol drug delivery has been advocated in clinical practice. Thus, this pilot observational study aims to investigate the feasibility of HFNC treatment with VMN for in-line bronchodilator delivery in patients with severe asthma. METHODS: This study was conducted from May 2022 to May 2023. Subjects ≥ 18 years old with a previous diagnosis of asthma who were admitted to the ED during severe exacerbation were included. The primary endpoint was the change in peak expiratory flow ratio (PEFR) after 2-h of treatment with bronchodilator delivered by HFNC with in-line VMN. Additional outcomes were changes in forced expiratory volume in 1 second (FEV1) and clinical variables before treatment. RESULTS: 30 patients mean age of 43 (SD ± 16) years, mostly female (67%) were studied. A significant change in PEFR (147 ± 31 L/m vs. 220 ± 38 L/m; p < 0.001) was observed after treatment with HFNC and in-line VMN with significant improvement in clinical variables. And no subjects required invasive mechanical ventilation (IMV) during the study. CONCLUSIONS: HFNC treatment with in-line VMN for bronchodilator delivery appears feasible and safe for patients with severe asthma exacerbation. These preliminary promising results should be confirmed with appropriately large-designed studies.

Nutrition intake, muscle thickness, and recovery outcomes for critically ill patients requiring non-invasive forms of respiratory support: A prospective observational study.

BACKGROUND: Use of high-flow nasal cannula (HFNC) and non-invasive ventilation (NIV) in the intensive care unit (ICU) is increasing, yet reporting of nutrition intake, muscle thickness, or recovery outcomes in this population is limited. OBJECTIVE: The objective of this study was to quantify muscle thickness, nutrition intake, and functional recovery outcomes for patients receiving HFNC/NIV within the ICU. METHODS: A single-centre, prospective, observational study in adult ICU patients recruited within 48 hrs of commencing HFNC/NIV. Change in quadriceps muscle layer thickness using ultrasound (primary outcome) and 24 hr nutrition intake from study inclusion to day 7 (D7), functional capacity (Barthel Index), and quality of life (EuroQol five-dimension five-level utility index) at D90 were assessed. Data are n (%), mean ± standard deviation or median [interquartile range], are compared using paired sample t-test, and a P value of <0.05 was considered significant. RESULTS: Primary outcome data were available for n = 28/42: 64 ± 13 y, 61% male, body mass index: 29.1 ± 9.0 kg/m2, and Acute Physiology and Chronic Health Evaluation II score: 17 ± 5. Quadriceps muscle layer thickness reduced from 2.41 ± 0.87 to 2.12 ± 0.73 cm; mean difference: -0.29 cm (95% confidence interval: -0.44, -0.13). Nutrition intake increased from study inclusion to D7: 1735 ± 1283 to 5448 ± 2858 kJ and 17.4 ± 16.6 to 60.9 ± 36.8g protein. Barthel Index was 87 ± 20 at baseline and 91 ± 15 at D90 (out of 100). Quality of life was impaired at D90: 0.64 ± 0.23 (health = 1.0). CONCLUSION: Critically ill patients receiving HFNC/NIV experienced muscle loss and impaired quality of life.

The Use of High-Flow Nasal Cannula in the Emergency Department and a Comparison of Its Efficacy With Noninvasive Ventilation.

BACKGROUND:  High-flow nasal cannula (HFNC) oxygenation has emerged as a convenient and handy oxygenation mode over the past few years, especially during the COVID-19 pandemic. HFNC is designed to provide humidified oxygen at high flow rates to subjects in a much more patient-compliant method. Noninvasive ventilation (NIV) has been a powerful tool in treating dyspneic patients of different etiologies, yielding positive outcomes over many decades. HFNC has the potential to serve as an alternative to NIV for acutely breathless patients, offering better patient compliance. METHODS:  A prospective observational study was conducted with a population size of 100 patients. The patients were randomly assigned to HFNC and NIV groups and further compared based on the clinical criteria, arterial oxygen pressure (PaO2)/fraction of inspired oxygen (FiO2) ratios, and modified Borg score. Simple proportions, mean, standard deviation, and chi-square tests were used. The chi-square test was applied to determine the association between the two attributes. RESULTS:  Both HFNC and NIV subset populations have shown substantial improvement in their clinical criteria in terms of respiratory rate, heart rate, oxygen saturation, PaO2/FiO2 ratios, and modified Borg score over two and six hours with statistically significant improvement in oxygen saturations among HFNC subset in comparison to NIV subset (at two hours, p = 0.004; at six hours, p = 0.022). Secondary outcomes like the need for intubation (14% in HFNC, 22% in NIV) and mortality (4% in HFNC, 6% in NIV group) were noted, which were statistically insignificant in comparing their efficacy. CONCLUSION:  The study concluded that HFNC resulted in better clinical parameters than NIV, but the difference was statistically insignificant except for oxygen saturation. Similarly, HFNC resulted in a decreased need for intubation and less mortality compared to NIV.

High flow nasal cannula oxygen therapy versus non-invasive ventilation for acute exacerbations of chronic obstructive pulmonary disease with acute-moderate hypercapnic respiratory failure: a randomized controlled non-inferiority trial.

BACKGROUND: Although cumulative studies have demonstrated a beneficial effect of high-flow nasal cannula oxygen (HFNC) in acute hypercapnic respiratory failure, randomized trials to compare HFNC with non-invasive ventilation (NIV) as initial treatment in acute exacerbations of chronic obstructive pulmonary disease (AECOPD) patients with acute-moderate hypercapnic respiratory failure are limited. The aim of this randomized, open label, non-inferiority trial was to compare treatment failure rates between HFNC and NIV in such patients. METHODS: Patients diagnosed with AECOPD with a baseline arterial blood gas pH between 7.25 and 7.35 and PaCO2 ≥ 50 mmHg admitted to two intensive care units (ICUs) at a large tertiary academic teaching hospital between March 2018 and December 2022 were randomly assigned to HFNC or NIV. The primary endpoint was the rate of treatment failure, defined as endotracheal intubation or a switch to the other study treatment modality. Secondary endpoints were rates of intubation or treatment change, blood gas values, vital signs at one, 12, and 48 h, 28-day mortality, as well as ICU and hospital lengths of stay. RESULTS: 225 total patients (113 in the HFNC group and 112 in the NIV group) were included in the intention-to-treat analysis. The failure rate of the HFNC group was 25.7%, while the NIV group was 14.3%. The failure rate risk difference between the two groups was 11.38% (95% CI 0.25-21.20, P = 0.033), which was higher than the non-inferiority cut-off of 9%. In the per-protocol analysis, treatment failure occurred in 28 of 110 patients (25.5%) in the HFNC group and 15 of 109 patients (13.8%) in the NIV group (risk difference, 11.69%; 95% CI 0.48-22.60). The intubation rate in the HFNC group was higher than in the NIV group (14.2% vs 5.4%, P = 0.026). The treatment switch rate, ICU and hospital length of stay or 28-day mortality in the HFNC group were not statistically different from the NIV group (all P > 0.05). CONCLUSION: HFNC was not shown to be non-inferior to NIV and resulted in a higher incidence of treatment failure than NIV when used as the initial respiratory support for AECOPD patients with acute-moderate hypercapnic respiratory failure. TRIAL REGISTRATION: chictr.org (ChiCTR1800014553). Registered 21 January 2018, http://www.chictr.org.cn.

Aerosol Delivery Efficiency With High-Flow Nasal Cannula Therapy in Neonatal, Pediatric, and Adult Nasal Upper-Airway and Lung Models.

BACKGROUND: High-flow nasal cannula (HFNC) systems employ different methods to provide aerosol to patients. This study compared delivery efficiency, particle size, and regional deposition of aerosolized bronchodilators during HFNC in neonatal, pediatric, and adult upper-airway and lung models between a proximal aerosol adapter and distal aerosol circuit chamber. METHODS: A filter was connected to the upper airway to a spontaneously breathing lung model. Albuterol was nebulized using the aerosol adapter and circuit at different clinical flow settings. The aerosol mass deposited in the upper airway and lung was quantified. Particle size was measured with a laser diffractometer. Regional deposition was assessed with a gamma camera at each nebulizer location and patient model with minimum flow settings. RESULTS: Inhaled lung doses ranged from 0.2-0.8% for neonates, 0.2-2.2% for the small child, and 0.5-5.2% for the adult models. Neonatal inhaled lung doses were not different between the aerosol circuit and adapter, but the aerosol circuit showed marginally greater lung doses in the pediatric and adult patient models. Impacted aerosols and condensation in the non-heated HFNC and aerosol delivery components contributed to the dispersion of coarse liquid droplets, high deposition (11-44%), and occlusion of the supine neonatal upper airway. In contrast, the upright pediatric and adult upper-airway models had minimal deposition (0.3-7.0%) and high fugitive losses (∼24%) from liquid droplets leaking out of the nose. The high impactive losses in the aerosol adapter (56%) were better contained than in the aerosol circuit, resulting in less cannula sputter (5% vs 22%), fewer fugitive losses (18% vs 24%), and smaller inhaled aerosols (5 µm vs 13 µm). CONCLUSIONS: The inhaled lung dose was low (1-5%) during HFNC. Approaches that streamline aerosol delivery are needed to provide safe and effective therapy to patients receiving aerosolized medications with this HFNC system.

[High-flow nasal oxygen versus conventional oxygen therapy during cesarean section under neuraxial anesthesia in pregnant women with heart disease: a randomized controlled trial].

OBJECTIVE: To evaluate the beneficial effects of high-flow nasal cannula (HFNC) oxygen therapy during cesarean section in pregnant women with heart disease. METHODS: We conducted a single-center, single-blinded randomized trial of HFNC oxygen therapy in pregnant women with heart disease undergoing cesarean section under neuraxial anesthesia.The participants were randomly assigned to receive either HFNC oxygen therapy with inspiratory flow of 30 L/min with 40% FIO2(n=27) or conventional oxygen therapy (COT) with oxygen flow rate of 5 L/min via a nasal cannula (n=31).The primary outcome was maternal desaturation (SpO2 < 94% lasting more than 3 min or PaO2/FIO2≤300 mmHg). RESULTS: Maternal desaturation was observed in 7.4%(2/27) of the women in HFNC group and in 32.3%(10/31) in the COT group.None of the cases required tracheal intubation during the perioperative period.The HFNC group had a significantly higher incidence of postoperative leukocytosis (P < 0.05) but without pyrexia or other inflammation-related symptoms.There were no significant differences between the two groups in the secondary maternal outcomes (need for respiratory support, maternal ICU admission, postoperative respiratory complications, and cardiovascular complications) or neonatal outcomes (P>0.05). CONCLUSION: In pregnant women with heart disease, HFNC therapy can significantly reduce the rate of maternal desaturation during the perioperative period of cesarean section without adverse effects on short-term maternal or fetal outcomes.