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High-flow nasal cannula (HFNC) oxygen therapy has recently shown clinical benefits in hypoxaemic acute respiratory failure (ARF) patients, while the value of noninvasive ventilation (NIV) remains debated. The primary end-point was to compare alveolar recruitment using global end-expiratory electrical lung impedance (EELI) between HFNC and NIV. Secondary end-points compared regional EELI, lung volumes (global and regional tidal volume variation (VT)), respiratory parameters, haemodynamic tolerance, dyspnoea and patient comfort between HFNC and NIV, relative to face mask (FM). A prospective randomised crossover physiological study was conducted in patients with hypoxaemic ARF due to pneumonia. They received alternately HFNC, NIV and FM. 16 patients were included. Global EELI was 4083 with NIV and 2921 with HFNC (p=0.4). Compared to FM, NIV and HFNC significantly increased global EELI by 1810.5 (95% CI 857–2646) and 826 (95% CI 399.5–2361), respectively. Global and regional VT increased significantly with NIV compared to HFNC or FM, but not between HFNC and FM. NIV yielded a significantly higher pulse oxygen saturation/inspired oxygen fraction ratio compared to HFNC (p=0.03). No significant difference was observed between HFNC, NIV and FM for dyspnoea. Patient comfort score with FM was not significantly different than with HFNC (p=0.1), but was lower with NIV (p=0.001). This study suggests a potential benefit of HFNC and NIV on alveolar recruitment in patients with hypoxaemic ARF. In contrast with HFNC, NIV increased lung volumes, which may contribute to overdistension and its potentially deleterious effect in these patients., This study found a potential benefit of HFNC and NIV on alveolar recruitment in patients with hypoxaemic ARF, but NIV also increases lung volumes, which may give rise to overdistension, reinforcing the concept of patient self-inflicted lung injury https://bit.ly/3iRcZDJ

Thermo-humidified nasal high flow (NHF) oxygen therapy is increasingly used in the management of respiratory failure. This therapy has recently gained attention as an alternative non-invasive respiratory support in several clinical scenarios, including acute and chronic settings. NHF enhances the patient's comfort and tolerance when compared with standard oxygen by supplying a heated and humidified mixture of air and oxygen at flows up to 60L/min. It can be delivered through different devices. Although few studies have compared the clinical effects of different NHF systems, the purpose of this paper is to describe the major benefits of NHF and to provide a quick guide on how to implement this therapy in daily practice. We have also included a brief description of the most frequently used NHF systems.

Introduction: Application of oxygen at high flows via nasal cannula can be used in patients with hypoxemic respiratory failure and to prevent reintubation. It is well tolerated by the patients and has been associated with lower mortality. However, there is very little data on the use of oxygen at high flows connected to tracheal cannula (HFOTC). Case presentation: We present two patients in whom weaning from mechanical ventilation was difficult and we decided to use HFOTC for weaning. Weaning from mechanical ventilation with HFOTC was successful in both patients and they tolerated long term (4 and 2 days, respectively) ventilatory support with HFOTC without adverse effects. Conclusions: HFOTC might be used during weaning from mechanical ventilation, however, more data is needed to determine the optimal use of this treatment option.

High flow oxygen therapy (HFOT) and Continuous positive airway pressure (CPAP) could be considered the most important ventilatory therapies during the COVID-19 pandemic because of their frequency of use. There are many devices on the market which provide this type of ventilatory support, and these should be distinguished from one another by their efficacy, versatility, patient comfort, hygiene and cost. We evaluated the AquaVENT FD140i from Armstrong Medical, which delivers both HFOT and CPAP, concluding that it provides two potentially efficacious treatments to COVID-19 patients, while its long-life battery facilitates transfers for escalation and de-escalation of care. We compared the AquaVENT FD140i with the Fisher & Paykel MR850, which is a gold standard in the market. We also looked at the compatibility of their humidifier and disposables with Armstrong Medical devices. The results of this study suggest the compatibility of both systems, which has the potential to reduce consumable costs.

Background The ratio of partial pressure of arterial oxygen to inspired oxygen fraction (PaO2/FIO2) during invasive mechanical ventilation (MV) is used as criteria to grade the severity of respiratory failure in acute respiratory distress syndrome (ARDS). During the SARS-CoV2 pandemic, the use of PaO2/FIO2 ratio has been increasingly used in non-invasive respiratory support such as high-flow nasal cannula (HFNC) and non-invasive ventilation (NIV). The grading of hypoxemia in non-invasively ventilated patients is uncertain. The main hypothesis, investigated in this study, was that the PaO2/FIO2 ratio does not change when switching between MV, NIV and HFNC. Methods We investigated respiratory function in critically ill patients with COVID-19 included in a single-center prospective observational study of patients admitted to the intensive care unit (ICU) at Uppsala University Hospital in Sweden. In a steady state condition, the PaO2/FIO2 ratio was recorded before and after any change between two of the studied respiratory support techniques (i.e., HFNC, NIV and MV). Results A total of 148 patients were included in the present analysis. We find that any change in respiratory support from or to HFNC caused a significant change in PaO2/FIO2 ratio. Changes in respiratory support between NIV and MV did not show consistent change in PaO2/FIO2 ratio. In patients classified as mild to moderate ARDS during MV, the change from HFNC to MV showed a variable increase in PaO2/FIO2 ratio ranging between 52 and 140 mmHg (median of 127 mmHg). This made prediction of ARDS severity during MV from the apparent ARDS grade during HFNC impossible. Conclusions HFNC is associated with lower PaO2/FIO2 ratio than either NIV or MV in the same patient, while NIV and MV provided similar PaO2/FIO2 and thus ARDS grade by Berlin definition. The large variation of PaO2/FIO2 ratio indicates that great caution should be used when estimating ARDS grade as a measure of pulmonary damage during HFNC.

Background When patients with a tracheostomy tube reach a stage in their care at which decannulation appears to be possible, it is common practice to cap the tracheostomy tube for 24 hours...

PurposeInfants hospitalized for an acute respiratory illness often require the use of noninvasive respiratory support during the initial stage to improve their breathing. High flow oxygen therapy (HFOT) is becoming a more popular means of noninvasive respiratory support, often used to treat respiratory syncytial virus/bronchiolitis. These infants present with tachypnea and coughing, resulting in difficulties in coordinating sucking and swallowing. However, they are often allowed to feed orally despite having high respiratory rate, increased work of breathing and on HFOT, placing them at risk for aspiration. Feeding therapists who work with these infants have raised concerns that HFOT creates an additional risk factor for swallowing dysfunction, especially with infants who have compromised airways or other comorbidities. There is emerging literature concluding changes in pharyngeal pressures with HFOT, as well as aspiration in preterm neonates who are on nasal continuous positive airway pressure. However, there is no existing research exploring the effect of HFOT on swallowing in infants with acute respiratory illness. This discussion will present findings from literature on HFOT, oral feeding in the acutely ill infant population, and present clinical practice guidelines for safe feeding during critical care admission for acute respiratory illness.ConclusionGuidelines for safety of oral feeds for infants with acute respiratory illness on HFOT do not exist. However, providers and parents continue to want to provide oral feeds despite clinical signs of respiratory distress and coughing. To address this challenge, we initiated a process change to use clinical bedside evaluation and a “cross-systems approach” to provide recommendations for safer oral feeds while on HFOT as the infant is recovering from illness. Use of standardized feeding evaluation and protocol have improved consistency of practice within our department. However, further research is still necessary to develop clinical practice guidelines for safe oral feeding for infants on HFOT.

BACKGROUND: We sought to evaluate the performance in terms of absolute humidity (AH), relative humidity (RH), and temperature of different heated humidifiers (HH) and circuits that are commonly used to deliver high-flow oxygen therapy in conventional ranges (30–60 L/min) and unconventional ranges (70–100 L/min). METHODS: In this prospective, observational study, an electronic thermohygrometer was used to obtain the required measurements. A mechanical ventilator was used as a source for high-flow nasal cannula oxygen therapy. For active humidification, the following equipment was used: a HH with standard disposable water trap circuit, 3 servo-controlled HH, and 7 circuits with a heated wire. Data on environmental conditions (ie, temperature, RH, AH) were collected from the laboratory during each measurement; the temperature, RH, and AH resulting from the application of 8 flows (30–100 L/min) were also recorded. Variables were compared with analysis of variance for repeated measurements with Tukey post hoc tests. A value of P RESULTS: During the study, a statistically significant difference was found in the average AH for each flow for the different devices (P 50 L/min, the best performance for all flows in terms of AH was found with the Fisher & Paykel MR850 HH, regardless of the circuit used. CONCLUSIONS: During oxygen therapy with very high gas flows, HH devices behave differently and in many cases are inefficient in delivering adequate humidification, even at conventional flows. Caution is therefore recommended when selecting the device and flow settings for the implementation of high-flow nasal cannula oxygen therapy.

Background Heated Humidified High Flow Nasal Cannula Oxygen Therapy (HHFNC) is increasingly used on the paediatric wards and High Dependency Units (HDU) for different types of pathologies and different age groups. We aimed to describe current practice related to the use of HHFNC on the paediatric wards and HDUs, weaning practices and preferred outcome measures for future research. Methods We carried out a cross-sectional online survey of UK paediatric consultants or their delegates working on the paediatric wards. Descriptive analysis of their geographical, and organizational characteristics, their specialties, and their level of experience was investigated. Reasons for HHFNC initiation, weaning criteria, patients’ characteristics and their primary pathologies were also analysed. Results Participation of 218 paediatricians from 81 hospitals (Median: 2.7, Range: 1–11) was registered. HHFNC was provided in most of the surveyed hospitals (93%, 75/81). A High Dependency Unit (HDU) was available in 47 hospitals (58%); less than a third of those have a dedicated paediatrician. Decisions around HHFNC were made solely by paediatricians in (75%) of the cases, mostly at hospitals with no HDU compared to those with dedicated HDUs (70.3% VS 36.6, 95%CI:22.6–50.4%, P Conclusion This survey showed support for developing paediatric-specific national guidance on the use of HHFNC on the wards. Our list of defined research priorities may help guide further collaborative research efforts in this field.

High-flow nasal oxygen systems are rapidly being adopted as an initial noninvasive treatment for acute respiratory failure. However, the term “high-flow nasal cannula” is nonspecific and leads to imprecise communication between physicians, respiratory therapists, and nurses with the potential for patient harm. In this viewpoint and a brief review of the technology, we argue for a change in nomenclature in order to reduce the chance for future clinical, administrative, and research misunderstanding surrounding high-flow nasal oxygen systems.

Major operations on the head and neck that involve microvascular reconstruction and a tracheostomy are prolonged procedures with considerable postoperative risk. Postoperative pulmonary complications are common because of mechanical ventilation, immobility, and inadequate humidification. High-flow heated oxygen therapy (HFOT) may overcome some of these issues, but we know of no published studies to support its use. The aim of this single-site randomised controlled trial therefore was to explore its feasibility and safety in these patients. Twenty patients were randomised to have HFOT (10 patients) or standard oxygen therapy (10 patients). HFOT was used from cessation of mechanical ventilation until decannulation of the tracheostomy. The primary outcome was feasibility. The secondary outcome measures explored the incidence of postoperative pulmonary complications, achievement of milestones of weaning from the tracheostomy, and hospital length of stay. A total of 21 patients were consecutively recruited and all provided informed consent. One who did not require a tracheostomy was later excluded. All patients initially had the intervention as planned, and one was electively changed to the control group because of discomfort caused by the high-flow oxygen. There were no adverse events or safety concerns in either group. Secondary outcomes showed a reduction in the incidence of pulmonary complications in the HFOT group. The use of HFOT is safe and feasible in patients who have microvascular reconstruction of the head and neck and a tracheostomy.

A clinical decision report using: Beigel JH, Tomashek KM, Dodd LE, et al. Remdesivir for the Treatment of Covid-19 — Final Report. N Engl J Med. 2020;383:1813-1826. https://doi.org/10.1056/NEJMoa2007764 for a patient with severe COVID-19.

Introduction Pulmonary complications occur in up to 38% of patients undergoing oesophagectomy and are associated with significant risk of mortality. Nasal high-flow oxygen (NHFO) has previously been shown to reduce respiratory complications following major abdominal surgery, however, its use in oesophagectomy has not previously been assessed. We report our results using NHFO routinely as part of our enhanced recovery protocol (ERP) in consecutive patients undergoing oesophagectomy for cancer at a single tertiary referral centre. Methods We recently incorporated routine postoperative NHFO following oesophagectomy as part of our ERP at Royal Stoke University Hospital. We conducted a prospective study of patients undergoing surgery between November 2019 and September 2020. The primary outcome measure was complications related to delivery of NHFO. Secondary endpoints included rates of pulmonary complications and mortality within 30 days of surgery. Results Fifty patients underwent oesophagectomy during the study period. The median age was 66 years (range 43-78 years) and male to female ratio was 4:1.Majority (49/50) of patients underwent 2-stage oesophagectomy while one underwent 3-stage oesophagectomy. All patients received postoperative NHFO. There were no complications related to NHFO. The 30-day overall pulmonary complication rate was 30%.Of these, 28% developed pneumonia,4% pulmonary embolism,and 2% pleural effusions requiring drainage. There were no deaths within 30 days of surgery. Conclusion Routine postoperative NHFO in consecutive patients undergoing oesophagectomy is safe and feasible with lower pulmonary complication rates than previously reported, leading to better overall outcomes. The value of NHFO in oesophagectomy requires further evaluation in a randomized clinical trial.

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Introduction: The efficacy of high-flow oxygen versus conventional oxygen therapy for asthma control remains controversial. We conduct a systematic review and meta-analysis to explore the influence of high-flow oxygen versus conventional oxygen therapy on asthma control. Methods: We have searched PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through May 2021 for randomized controlled trials (RCTs) assessing the efficacy of high-flow oxygen versus conventional oxygen therapy for asthma control. This meta-analysis is performed using the random-effect model.Results: Four RCTs are included in the meta-analysis. Overall, compared with conventional oxygen therapy for asthma, high-flow oxygen is associated with significantly lower dyspnea score (SMD=-0.63; 95% CI=-1.08 to -0.17; P=0.008), but reveals no remarkable influence on PaCO2 (SMD=0.28; 95% CI=-0.22 to 0.77; P=0.28), PaO2 (SMD=0.44; 95% CI=-1.34 to 2.22; P=0.63), intubation (OR=1.09; 95% CI=0.15 to 8.21; P=0.93) or hospital length of stay (SMD=-0.07; 95% CI=-0.41 to 0.27; P=0.67). Conclusions: High-flow oxygen may benefit to reduce dyspnea score than conventional oxygen therapy for asthma.

Background: Tracheal resection and reconstruction are the most effective treatment tracheal stenosis, but the difficulties are surgery and maintaining ventilation performed on the patient's same airway. High‐flow oxygen has begun to be applied prolonging the apnoea time in the tracheal anastomosis period for tracheal resection and reconstruction. This study aims to evaluate the effectiveness of apnoeic conditions with high‐flow oxygen as the sole method of gas exchange during anastomosis construction. Methods: A prospective study was performed on 16 patients with tracheal stenosis, with ages ranging from 19 to 70, underwent tracheal resection and reconstruction from April 2019 to August 2020 in 108 Military Central Hospital. During the anastomosis phase using high flow oxygen of 35-40 L/min delivered across the open tracheal with an endotracheal tube (ETT) at the glottis in apnoeic conditions. Results: The mean (SD) apnoea time was 20.91 (2.53) mins. Mean (SD) time anastomosis was 22.9 (2.41) mins. The saturation of oxygen was stable during all procedures at 98-100%. Arterial blood gas analysis showed mean (SD) was hypercapnia and acidosis acute respiratory after 10 mins of apnoea and 20 mins apnoea respectively. However, after 15 mins of ventilation, the parameters are ultimately returned to normal. All 16 patients were extubated early and safely at the end of the operation. There were no complications, such as bleeding, hemothorax, pneumothorax, or barotrauma.Conclusion: High-flow oxygen across the open tracheal under apnoeic conditions can provide a satisfactory gas exchange to allow tubeless anesthesia for tracheal resection and reconstruction.

Introduction: High-flow nasal cannula (HFNC) is a safe and effective treatment in bronchiolitis in paediatric wards. The optimal flow on starting HFNC is still unknown. The main aim of this study was to determine if there were differences in clinical outcome of patients according the initial flow. Methods: A prospective, observational and analytical study was conducted between 2014 and 2016 on infants admitted with bronchiolitis and who required HFNC. Two cohorts were established according to the initial flow: cohort 1: flow 15 L/min (HFNC-15), and cohort 2: flow 10 L/min (HFNC-10). Treatment failure was defined as the presentation of apnoea or the absence of clinical improvement in the first 12–24 h. Multivariate probabilistic models were built to identify predictive variables of treatment failure. Results: A total of 57 patients were included. The median age was 4 months (IQR 2–13), and 54% received treatment with HFNC-10 and 46% with HFNC-15. In HFNC-15 cohort, respiratory rate (RR) decreased in the first hour, and in the HFNC-10 cohort in the first 6 h (P = .03). In HFNC-10 cohort, treatment failure rate was 71%, compared to 15% of HFNC-15 (P

BACKGROUND: During high-flow oxygen therapy, heated humidified gas is delivered at high flow. Although the warmth and humidity of this gas facilitates mucociliary function in the lower airway, warm and humid conditions also promote bacterial growth. Bacterial contamination of high-flow oxygen therapy circuits has not been well investigated. We examined the incidence of bacterial contamination in high-flow oxygen therapy circuits. METHODS: This was a prospective observational study in a university hospital 10-bed general ICU. After final high-flow oxygen therapy discontinuation, samples were obtained from the interface and the chamber ends of the circuit. Initially, a half circumference of each inner surface was swabbed, after which the whole circuit was left in the ICU at room temperature for 6 h. The samples were then, in the same way, taken from the previously unswabbed arcs of the end inner surfaces. All the samples were sent to a biology laboratory and cultured. RESULTS: In all, 118 samples were collected from 31 circuits. The median duration of high-flow oxygen therapy was 48 h (interquartile range, 26–96 h). Of 31 circuits, contamination occurred in 5 circuits (16.1% [95% CI 5.5–33.7%]). CONCLUSIONS: Bacterial contamination of inner surfaces of the circuit after high-flow oxygen therapy was relatively high.

Due to the limited number of critical care providers in the United States, even well-staffed hospitals are at risk of exhausting both physical and human resources during the outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). One potential response to this problem is redeployment of non-critical care providers to increase the supply of available clinicians. To support efforts to increase capacity as part of surge preparation for the coronavirus disease (COVID-19) outbreak, we created an online educational resource for nonintensivist providers to learn basic critical care content. Among those materials, we created a series of one-page learning guides for the management of common problems encountered in the intensive care unit (ICU). These guides were meant to be used as just-in-time tools to guide problem-solving during the provision of ICU care. This article presents five guides related to the evaluation and management of patients with hypoxemic respiratory failure and the basics of invasive mechanical ventilation.

Introduction High-flow nasal oxygen (HFNO) is increasingly used as part of ward-based treatment, especially for oncology patients with respiratory failure that is either directly due to the underlying malignancy or secondary to anti-cancer drugs or radiotherapy-induced pneumonitis. Patient selection is paramount to its success, as unsuitable selection can result in delays in appropriate palliation, leading to unrealistic expectations for relatives. Methods We performed a retrospective audit of 40 patients across both Gloucester Royal and Cheltenham General Hospitals, who received HFNO on the respiratory wards over July-December 2019. Results The average age for patients receiving HFNO was 74 years with mortality rates being the highest at 80% in the 80–89 years age group. Interestingly, 81% of patients with HFNO as their ceiling of treatment died and only 10% of patients deemed for full escalation of treatment died. The majority of referrals were from medical specialities, closely followed by oncology. The oncology patients did show the highest mortality rates. The majority of patients referred for NHFO were those deemed not to be appropriate for escalation to ITU. Conclusion Our experience demonstrates that the mortality of oncology patients on HFNO is high. Although starting HFNO in these patient groups might be appropriate if we can demonstrate evidence of reversible pathology, care needs to be taken in managing the expectations of patients and their families, and where relevant, appropriate palliative input sought.

A 44-year-old COVID-19 positive patient was transferred to our hospital with worsening acute hypoxemic respiratory failure. She was admitted to ICU and was started on high flow oxygen. Her CXR showed worsening bilateral infiltrates. In order to prevent her progression from severe to critical disease, we adopted a multiple modality treatment approach, utilizing clinical judgment and most recent publications. She was treated with antibiotics, convalescent plasma, steroids, hydroxychloroquine and self-proning. After 43 hours, her CXR showed rapid clearing of infiltrates and we could discharge her on day three of hospitalization. Previously reported case series on convalescent plasma showed the number of days taken for significant improvement in chest x-ray varied from 4 to 7 days. The rapidity of improvement in this patient is remarkable and could be due to the multiple modality treatment approach.

Objectives In a conventional hospital ward, we used high-flow nasal oxygen (HFNO) to treat elderly COVID-19 patients noneligible for intensive care unit transfer. Methods This study was conducted in the Institut Hospitalo-Universitaire Mediterranee Infection, Assistance Publique-Hopitaux de Marseille (AP-HM), France. We used high-flow nasal oxygen (HFNO) in our conventional infectious disease ward from 15 September 2020 for elderly patients noneligible for intensive care unit transfer. Results Of the 44 patients (median age 83 years (57–94), mean: 80.25), 61.4% (27/44) were men. The median Charlson score was 7 (1–15). The median of the NEWS-2 score upon admission was 8 (3–11) and was 10 at the time of initiation of HFNO. The median PaO2/FiO2 ratio was 103 (71–151) prior to HNFO initiation. Among the 44 patients, 16 patients (36.4%) had been weaned from HFNO, and 28 patients had died (63.6%). Conclusions In this preliminary report, we observed that HFNO saved the lives of one-third of elderly COVID-19 patients who would have systematically died.

Non-invasive respiratory support (NIRS) in adult, pediatric, and neonatal patients with acute respiratory failure (ARF) comprises two treatment modalities, non-invasive mechanical ventilation (NIMV) and high-flow nasal cannula (HFNC) therapy. However, experts from different specialties disagree on the benefit of these techniques in different clinical settings. The objective of this consensus was to develop a series of good clinical practice recommendations for the application of non-invasive support in patients with ARF, endorsed by all scientific societies involved in the management of adult and pediatric/neonatal patients with ARF. To this end, the different societies involved were contacted, and they in turn appointed a group of 26 professionals with sufficient experience in the use of these techniques. Three face-to-face meetings were held to agree on recommendations (up to a total of 71) based on a literature review and the latest evidence associated with 3 categories: indications, monitoring and follow-up of NIRS. Finally, the experts from each scientific society involved voted telematically on each of the recommendations. To classify the degree of agreement, an analogue classification system was chosen that was easy and intuitive to use and that clearly stated whether the each NIRS intervention should be applied, could be applied, or should not be applied. (C) 2020 SEPAR. Published by Elsevier Espana, S.L.U. All rights reserved.

Objective: The most common reason for intensive care unit admission is acute respiratory failure and after extubation mainly three methods are used to bring the PaO2 level to a sufficient level: conventional oxygen therapy (COT), high flow oxygen therapy (HFO), and non-invasive ventilation (NIV). The aim of this study was to determine if NIV or HFO is beneficial in decreasing weaning failure in high-risk patient population (HRP) and compare these noninvasive methods. Methods: This prospective, observational cohort study was conducted between March 2019 and March 2020 in a tertiary state hospital in Turkey. Our study included 3 main groups as COT, HFO, and NIV. Results: During the study period, 71 patients were enrolled in this study and 24 patients were in the COT group, 22 HFO group, and 25 in the NIV group. The mean duration of mechanical ventilation assistance (MVA) before extubation was 5.8 days and the mean PaO2 was highest in the HFO group 6 hours after extubation with a statistically significant difference (p

Background: The global active prevalence of migraines is approximately 14.7%. Oxygen therapy may reduce the use of non-steroidal anti-inflammatory drugs (NSAIDs) which often have various negative side effects. The purpose of this systematic review is to analyze the literature on the efficacy of high flow oxygen for the management of headache disorders, compared to placebo treatment. Methods: Studies were identified by PubMed, Web of Science and Scopus database from 1980 to the 30 October 2020. The search included the following terms: “oxygen therapy” and “headache” and “migraine”. Studies were included if high flow oxygen was used in the treatment of headache disorders. All selected studies were qualitatively analyzed. Results: Our literature search identified 71 studies, of which 65 were discarded and 6 were included in the meta-analysis. The random effect model did not show a pooled significant resolution of headache disorders (OR 2.08 (95% CI 0.92–4.70), p < 0.0001) in the oxygen therapy group compared to the placebo group. Conclusion: In our systematic review of six studies, there were no significant differences between high flow oxygen and placebo treatment groups.

Combining inhaled drug delivery with high flow nasal cannula (HFNC) therapy is greatly used in hospital settings to allow the administration of scheduled doses of inhaled drugs without the discontinuation of gas flow in critically ill patients. Factors that determine the amount of aerosol delivery within a high flow system are flow rate of gas, gas density, type of aerosol generator, and its position and interface type. The increase in both flow rate and density of the delivered gas negatively affects the aerosol output from these systems. Additionally, vibrating mesh nebulizers are considered the best aerosol generators to be used within the high flow system when compared with both jet nebulizers and pressurized metered-dose inhalers (pMDIs). The loss of aerosol within HFNC systems was found to be significantly high which might be returned to the humidification and heating of medical gas delivered. Narrow therapeutic indexed and high-cost drugs are greatly affected by such limitations. Further clinical studies are needed to evaluate this modality of aerosol delivery in various disease conditions.