The Effect of High-Flow Nasal Cannula Oxygen Therapy on Mortality and Intubation Rate in Acute Respiratory Failure: A Systematic Review and Meta-Analysis

High-flow nasal cannula oxygen therapy is equally effective to noninvasive ventilation for mild-moderate acute respiratory distress syndrome in patients with acute pancreatitis: A single-center, retrospective cohort study

BACKGROUND

The use of high-flow nasal cannula (HFNC) oxygen therapy is gaining popularity for the treatment of acute hypoxic respiratory failure. However, limited evidence exists regarding the effectiveness of HFNC for acute respiratory distress syndrome (ARDS) in patients with acute pancreatitis (AP).

METHODS

This retrospective analysis focused on AP patients with mild-moderate ARDS, who were treated with either HFNC or noninvasive ventilation (NIV) in the emergency medicine department, from January 2020 to December 2022. The primary endpoint was treatment failure, defined as either invasive ventilation or a switch to any other study treatment (NIV for patients in the NFNC group and vice versa).

RESULTS

A total of 146 patients with AP (68 in the HFNC group and 78 in the NIV group) were included in this study. The treatment failure rate in the HFNC group was 17.6% and 19.2% in the NIV group - a risk difference of -1.6% (95% CI, -11.3 to 14.0%; P = 0.806). The most common causes of failure in the HFNC group were aggravation of respiratory distress and hypoxemia. However, in the NIV group, the most common reasons for failure were treatment intolerance and exacerbation of respiratory distress. Treatment intolerance in the HFNC group was significantly lower than that in the NIV group (16.7% vs 60.0%, 95% CI -66.8 to -6.2; P = 0.023). Multivariate logistic regression analysis showed that body mass index (≥28), acute physiology and chronic health evaluation II score (≥15), partial arterial oxygen tension/fraction of inspired oxygen (≤200), and respiratory rate (≥32/min) at 1 hour were independent predictors of HFNC failure.

CONCLUSION

In AP patients with mild-moderate ARDS, the usage of HFNC did not lead to a higher rate of treatment failure when compared to NIV. HFNC is an ideal choice of respiratory support for patients with NIV intolerance, but clinical application should pay attention to the influencing factors of its treatment failure.

High-flow nasal cannula versus standard low-flow nasal cannula during deep sedation in patients undergoing radiofrequency atrial fibrillation catheter ablation: a single-centre randomised controlled trial

Background

To our knowledge, there are few trials studying the effect of high-flow nasal cannula (HFNC) during deep sedation. Our hypothesis is that high-flow nasal cannula (HFNC) will prevent hypoxemia and desaturation as compared to low-flow nasal cannula (LFNC) during prolonged deep sedation in patients with atrial fibrillation undergoing radiofrequency catheter ablation (RFCA).

Methods

A single-centre, randomised controlled trial with HFNC as the intervention and LFNC as the control group. A total of 94 adult patients per group undergoing elective radiofrequency atrial fibrillation catheter ablation under deep sedation. will be included. The primary outcome is the lowest oxygen saturation (SpO2). Secondary outcomes are as follows: the duration of lowest SpO2, cross over from oxygen therapy in both directions, incidence of SpO2 below 90% > 60 seconds, adverse sedation events, adverse effects of HFNC, mean CO2, peak CO2 and patients experience with oxygen therapy. The study will take place during the 2-day admission period for RFCA. Patients can fill out their questionnaires in the first week after treatment.

Discussion

HFNC is increasingly used as a technique for oxygen delivery in procedural sedation and analgesia. We hypothesise that HFNC is superior to the standard treatment LFNC in patients under deep sedation with respect to the incidence of desaturation. To our knowledge, there are no adequately powered clinical trial studies on the effects of HFNC in prolonged deep sedation.

Trial registration

ClinicalTrials.gov NCT04842253. Registered on 04 April 2021

Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is a prevalent and important cause of respiratory failure. Underlying causes include pulmonary and non-pulmonary aetiologies. ARDS is acute hypoxaemic respiratory failure associated with non-cardiogenic pulmonary oedema, reduced pulmonary compliance, and can lead to lung fibrosis. In addition to treating the underlying cause, often the mainstay of the management of ARDS is invasive mechanical ventilation. This can perpetuate lung injury—ventilator-associated lung injury (VALI). Despite recent advances in our understanding of this, ARDS-associated morbidity and mortality remains high. This chapter discusses the pathophysiology of ARDS and its management, including mechanical ventilation, adjunctive therapies, and some recently trialed pharmacotherapies.

Management of pneumonia in critically ill patients

Severe pneumonia is associated with high mortality (short and long term), as well as pulmonary and extrapulmonary complications. Appropriate diagnosis and early initiation of adequate antimicrobial treatment for severe pneumonia are crucial in improving survival among critically ill patients. Identifying the underlying causative pathogen is also critical for antimicrobial stewardship. However, establishing an etiological diagnosis is challenging in most patients, especially in those with chronic underlying disease; those who received previous antibiotic treatment; and those treated with mechanical ventilation. Furthermore, as antimicrobial therapy must be empiric, national and international guidelines recommend initial antimicrobial treatment according to the location's epidemiology; for patients admitted to the intensive care unit, specific recommendations on disease management are available. Adherence to pneumonia guidelines is associated with better outcomes in severe pneumonia. Yet, the continuing and necessary research on severe pneumonia is expansive, inviting different perspectives on host immunological responses, assessment of illness severity, microbial causes, risk factors for multidrug resistant pathogens, diagnostic tests, and therapeutic options.

[Weaning from invasive mechanical ventilation]

Weaning from invasive mechanical ventilation is challenging for the ICU team in terms of shortening time of ventilation via endotracheal tube in order to improve the patient's prognosis by early extubation. Thereby prolonged mechanical ventilation (> 14 days), which is associated with risk of tracheotomy and prolonged weaning, shall be avoided. This article will give an overview about weaning categories, causes for weaning failure and strategies to overcome this problem. In the last part we will cover concepts in the process of prolonged weaning including discharge management with invasive mechanical ventilation.

A Review of High Flow Nasal Cannula Oxygen Therapy in Human and Veterinary Medicine

Respiratory distress is a common ailment in small animal medicine. Oxygen supplementation is a mainstay of initial therapy. High Flow Nasal Cannula Oxygen Therapy (HFNCOT) has become increasingly popular as a treatment modality in human medicine, and more recently in canine patients. These devices deliver high flow rates of heated and humidified oxygen at an adjustable fraction of inspired oxygen (FiO₂). This article reviews current literature in human patients on HFNCOT as well as studies that have evaluated its use in veterinary patients. A discussion of the respiratory physiology that is associated with respiratory distress, in addition to an overview of currently available oxygen supplementation modalities is provided. The physiologic benefits of HFNCOT are explained, as are technical aspects associated with its use. Recommendations on initial settings, maintenance therapy, and weaning are also described.

High-flow nasal oxygen reduces endotracheal intubation: a randomized clinical trial

Background:

The benefits of high-flow nasal cannula (HFNC) as primary intervention in patients with acute hypoxemic respiratory failure (AHRF) are still a matter in debate. Our objective was to compare HFNC therapy versus conventional oxygen therapy (COT) in the prevention of endotracheal intubation in this group of patients.

Methods:

An open-label, controlled and single-centre clinical trial was conducted in patients with severe AHRF, defined by a PaO₂/FIO₂ ratio ⩽200, to compare HFNC with a control group (CG) treated by COT delivered through a face mask, with the need to perform intubation as the primary outcome. The secondary outcomes included tolerance of the HFNC device and to look for the predictive factors for intubation in these patients.

Results:

A total of 46 patients were included (22 in the COT group and 24 in the HFNC group) 48% of whom needed intubation: 63% in the COT group and 33% in the HFNC group, with significant differences both in intention to treat [χ² = 4.2; p = 0.04, relative risk (RR) = 0.5; confidence interval (CI) 95%: 0.3–1.0] and also in treatment analysis (χ² = 4.7; p = 0.03; RR = 0.5; IC 95%: 0.3–0.9) We obtained a number needed to treat (NNT) = 3 patients treated to avoid an intubation. Intubation occurred significantly later in the HFNC group. Estimated PaO₂/FIO₂, respiratory rate and dyspnea were significantly better in the HFNC group. Patients treated with HFNC who required intubation presented significant worsening after the first 8 h, as compared with non-intubated HFNC group patients. Mortality was 22% with no differences. The HFNC group patients were hospitalized for almost half of the time in the intensive care unit (ICU) and in the ward, with significantly less hospital length of stay. A total of 14 patients in the HFNC group (58%) complained of excessive heat and 17% of noise; 3 patients did not tolerate HFNC.

Conclusion:

Patients with severe acute hypoxemic respiratory failure who tolerate HFNC present a significantly lower need for endotracheal intubation compared with conventional oxygen therapy.

Clinical Trial Register

EUDRA CT number: 2012-001671-36

The reviews of this paper are available via the supplemental material section.

The Role of Noninvasive Respiratory Management in Patients with Severe COVID-19 Pneumonia

Acute hypoxemic respiratory failure is the principal cause of hospitalization, invasive mechanical ventilation and death in severe COVID-19 infection. Nearly half of intubated patients with COVID-19 eventually die. High-Flow Nasal Oxygen (HFNO) and Noninvasive Ventilation (NIV) constitute valuable tools to avert endotracheal intubation in patients with severe COVID-19 pneumonia who do not respond to conventional oxygen treatment. Sparing Intensive Care Unit beds and reducing intubation-related complications may save lives in the pandemic era. The main drawback of HFNO and/or NIV is intubation delay. Cautious selection of patients with severe hypoxemia due to COVID-19 disease, close monitoring and appropriate employment and titration of HFNO and/or NIV can increase the rate of success and eliminate the risk of intubation delay. At the same time, all precautions to protect the healthcare personnel from viral transmission should be taken. In this review, we summarize the evidence supporting the application of HFNO and NIV in severe COVID-19 hypoxemic respiratory failure, analyse the risks associated with their use and provide a path for their proper implementation.

Effect of high-flow nasal cannula oxygen therapy in patients with chronic obstructive pulmonary disease: A meta-analysis

BACKGROUND

High-flow nasal cannula oxygen therapy reduces the arterial partial pressure of carbon dioxide and acute exacerbation but does not increase exercise capacity or decrease hospitalisation or mortality. The study aimed to test the hypothesis that in chronic obstructive pulmonary disease patients, the use of high-flow nasal cannula decreases arterial partial pressure of carbon dioxide and increases the partial pressure of oxygen and 6-min walking distance.

METHODS

PubMed, Embase and the Cochrane library were searched for eligible studies published from database inception to November 2020 (Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist). The primary outcomes were partial pressure of carbon dioxide and partial pressure of oxygen, and the secondary outcomes were transcutaneous partial pressure of carbon dioxide and 6-min walking distance.

RESULTS

Nine studies (680 patients) were included. high-flow nasal cannula did not decrease partial pressure of carbon dioxide compared with the control interventions (mean difference = -0.81, 95% confidence interval: -2.68 to 1.06, p = .395; I²  = 42.9%, p_{heterogeneity}  = .105). high-flow nasal cannula decreased partial pressure of carbon dioxide compared with long-term oxygen therapy (mean difference = -3.25, 95% confidence interval: -5.65 to -0.85, p = .008; I²  = 0%, p_{heterogeneity}   = .375); no difference was observed for the control modalities. high-flow nasal cannula resulted in better partial pressure of carbon dioxide compared with control interventions in hypoxemic patients (mean difference = -2.59, 95% confidence interval: -4.82 to -0.35, p = .023; I²  = 32.5%, p_{heterogeneity}  = .224), but not in other types of patients. high-flow nasal cannula did not increase partial pressure of oxygen compared with the control interventions (mean difference = 1.17, 95% confidence interval: -1.50 to 3.83, p = .390; I²  = 0%, p_{heterogeneity}  = .660). high-flow nasal cannula decreased transcutaneous carbon dioxide tension (transcutaneous partial pressure of carbon dioxide) compared with the control interventions (mean difference = 2.37, 95% confidence interval: 0.07-4.68, p = .044; I²  = 8.7%, p_{heterogeneity}   = .295). high-flow nasal cannula increased 6-min walking distance compared with the control interventions (mean difference = 18.22, 95% confidence interval: 0.86-,35.57, p = .040; I²  = 0%, p_{heterogeneity}  = .918). The sensitivity analyses showed that the results were robust.

CONCLUSIONS

High-flow nasal cannula did not significantly decrease partial pressure of carbon dioxide or increase partial pressure of oxygen in chronic obstructive pulmonary disease patients, which is different from the previous meta-analysis, but it decreases transcutaneous partial pressure of carbon dioxide and increased 6-min walking distance.

RELEVANCE TO CLINICAL PRACTICE

This meta-analysis shows that in patients with chronic obstructive pulmonary disease, high-flow nasal cannula improves both transcutaneous partial pressure of carbon dioxide and 6-min walking distance, suggesting the high-flow nasal cannula has benefits in the management of chronic obstructive pulmonary disease. Considering that the literature suggests no impact of high-flow nasal cannula on hospitalisation and mortality, the benefits of high-flow nasal cannula might be limited to the patients who survive the chronic obstructive pulmonary disease events. Still, the global impact of high-flow nasal cannula on the quality of life of patients with chronic obstructive pulmonary disease should be examined.

Effectiveness and Harms of High-Flow Nasal Oxygen for Acute Respiratory Failure: An Evidence Report for a Clinical Guideline From the American College of Physicians

BACKGROUND

Use of high-flow nasal oxygen (HFNO) for treatment of adults with acute respiratory failure (ARF) has increased.

PURPOSE

To assess HFNO versus noninvasive ventilation (NIV) or conventional oxygen therapy (COT) for ARF in hospitalized adults.

DATA SOURCES

English-language searches of MEDLINE, Embase, CINAHL, and Cochrane Library from January 2000 to July 2020; systematic review reference lists.

STUDY SELECTION

29 randomized controlled trials evaluated HFNO versus NIV (k = 11) or COT (k = 21).

DATA EXTRACTION

Data extraction by a single investigator was verified by a second, 2 investigators assessed risk of bias, and evidence certainty was determined by consensus.

DATA SYNTHESIS

Results are reported separately for HFNO versus NIV, for HFNO versus COT, and by initial or postextubation management. Compared with NIV, HFNO may reduce all-cause mortality, intubation, and hospital-acquired pneumonia and improve patient comfort in initial ARF management (low-certainty evidence) but not in postextubation management. Compared with COT, HFNO may reduce reintubation and improve patient comfort in postextubation ARF management (low-certainty evidence).

LIMITATIONS

Trials varied in populations enrolled, ARF causes, and treatment protocols. Trial design, sample size, duration of treatment and follow-up, and results reporting were often insufficient to adequately assess many outcomes. Protocols, clinician and health system training, cost, and resource use were poorly characterized.

CONCLUSION

Compared with NIV, HFNO as initial ARF management may improve several clinical outcomes. Compared with COT, HFNO as postextubation management may reduce reintubations and improve patient comfort; HFNO resulted in fewer harms than NIV or COT. Broad applicability, including required clinician and health system experience and resource use, is not well known.

PRIMARY FUNDING SOURCE

American College of Physicians. (PROSPERO: CRD42019146691).

Association of noninvasive respiratory support with mortality and intubation rates in acute respiratory failure: a systematic review and network meta-analysis

BACKGROUND

Noninvasive respiratory support devices may reduce the tracheal intubation rate compared with conventional oxygen therapy (COT). To date, few studies have compared high-flow nasal cannula (HFNC) use with noninvasive positive-pressure ventilation (NPPV). We conducted a network meta-analysis to compare the effectiveness of three respiratory support devices in patients with acute respiratory failure.

METHODS

The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and Ichushi databases were searched. Studies including adults aged ≥ 16 years with acute hypoxic respiratory failure and randomized-controlled trials that compared two different oxygenation devices (COT, NPPV, or HFNC) before tracheal intubation were included. A frequentist-based approach with a multivariate random-effects meta-analysis was used. The network meta-analysis was performed using the GRADE Working Group approach. The outcomes were short-term mortality and intubation rate.

RESULTS

Among 5507 records, 27 studies (4618 patients) were included. The main cause of acute hypoxic respiratory failure was pneumonia. Compared with COT, NPPV and HFNC use tended to reduce mortality (relative risk, 0.88 and 0.93, respectively; 95% confidence intervals, 0.76-1.01 and 0.80-1.08, respectively; both low certainty) and lower the risk of endotracheal intubation (0.81 and 0.78; 0.72-0.91 and 0.68-0.89, respectively; both low certainty); however, short-term mortality or intubation rates did not differ (0.94 and 1.04, respectively; 0.78-1.15 and 0.88-1.22, respectively; both low certainty) between NPPV and HFNC use.

CONCLUSION

NPPV and HFNC use are associated with a decreased risk of endotracheal intubation; however, there are no significant differences in short-term mortality.

TRIAL REGISTRATION

PROSPERO (registration number: CRD42020139105 , 01/21/2020).

The Impact of High-Flow Nasal Cannula Use on Patient Mortality and the Availability of Mechanical Ventilators in COVID-19

Rationale: How to provide advanced respiratory support for coronavirus disease (COVID-19) to maximize population-level survival while optimizing mechanical ventilator access is unknown.Objectives: To evaluate the use of high-flow nasal cannula for COVID-19 on population-level mortality and ventilator availability.Methods: We constructed dynamical (deterministic) simulation models of high-flow nasal cannula and mechanical ventilation use for COVID-19 in the United States. Model parameters were estimated through consensus based on published literature, local data, and experience. We had the following two outcomes: 1) cumulative number of deaths and 2) days without any available ventilators. We assessed the impact of various policies for the use of high-flow nasal cannula (with or without "early intubation") versus a scenario in which high-flow nasal cannula was unavailable.Results: The policy associated with the fewest deaths and the least time without available ventilators combined the use of high-flow nasal cannula for patients not urgently needing ventilators with the use of early mechanical ventilation for these patients when at least 10% of ventilator supply was not in use. At the national level, this strategy resulted in 10,000-40,000 fewer deaths than if high-flow nasal cannula were not available. In addition, with moderate national ventilator capacity (30,000-45,000 ventilators), this strategy led to up to 25 (11.8%) fewer days without available ventilators. For a 250-bed hospital with 100 mechanical ventilators, the availability of 13, 20, or 33 high-flow nasal cannulas prevented 81, 102, and 130 deaths, respectively.Conclusions: The use of high-flow nasal cannula coupled with early mechanical ventilation when supply is sufficient results in fewer deaths and greater ventilator availability.

High flow nasal cannula oxygen and non-invasive mechanical ventilation in management of COVID-19 patients with acute respiratory failure: a retrospective observational study

Background

High flow nasal cannula oxygen (HFNCO) is a relatively new technique used to deliver oxygen in respiratory failure patients. This retrospective study is aiming to assess the role and benefits of using HFNCO compared to non-invasive ventilation (NIV) in management of patients with acute hypoxemic respiratory failure associated with coronavirus disease 2019 (COVID-19).

Results

A retrospective analysis of the files of 63 patients with COVID-19 and acute hypoxemic respiratory failure admitted to the intensive care unit (ICU), 37 patients received HFNCO as initial therapy, and 26 patients were primarily treated with NIV. There was no significant difference between the 2 groups in terms of baseline characteristics, laboratory tests, arterial blood gases, PaO2/FiO2 values, and vital signs. Re-assessment after 24 h of starting treatment with either HFNCO or NIV showed significant improvement (P<0.01) in the respiratory rate, heart rate, and oxygenation parameters. The magnitude of improvement of the vital signs and oxygenation was not significantly different between patients using HFNCO or NIV. Success rate of HFNCO was 86.4%, endotracheal intubation with invasive mechanical ventilation was required in 10.81% of patients, and mortality rate was 2.7%. Success rate of NIV was 84.6%, endotracheal intubation rate was 11.53%, and mortality rate was 3.8%. No significant difference (P>0.05) between the 2 groups as regards the duration of treatment, rate of endotracheal intubation with invasive mechanical ventilation, and mortality rate.

Conclusion

High flow nasal cannula oxygen (HFNCO) is effective in the management of acute hypoxemic respiratory failure associated with COVID-19. Its efficacy is similar to NIV, with no difference in the duration of treatment, endotracheal intubation rate, or mortality rate.

High-flow nasal cannulae for respiratory support in adult intensive care patients

BACKGROUND

High-flow nasal cannulae (HFNC) deliver high flows of blended humidified air and oxygen via wide-bore nasal cannulae and may be useful in providing respiratory support for adults experiencing acute respiratory failure, or at risk of acute respiratory failure, in the intensive care unit (ICU). This is an update of an earlier version of the review.

OBJECTIVES

To assess the effectiveness of HFNC compared to standard oxygen therapy, or non-invasive ventilation (NIV) or non-invasive positive pressure ventilation (NIPPV), for respiratory support in adults in the ICU.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, Web of Science, and the Cochrane COVID-19 Register (17 April 2020), clinical trial registers (6 April 2020) and conducted forward and backward citation searches.

SELECTION CRITERIA

We included randomized controlled studies (RCTs) with a parallel-group or cross-over design comparing HFNC use versus other types of non-invasive respiratory support (standard oxygen therapy via nasal cannulae or mask; or NIV or NIPPV which included continuous positive airway pressure and bilevel positive airway pressure) in adults admitted to the ICU.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by Cochrane.

MAIN RESULTS

We included 31 studies (22 parallel-group and nine cross-over designs) with 5136 participants; this update included 20 new studies. Twenty-one studies compared HFNC with standard oxygen therapy, and 13 compared HFNC with NIV or NIPPV; three studies included both comparisons. We found 51 ongoing studies (estimated 12,807 participants), and 19 studies awaiting classification for which we could not ascertain study eligibility information. In 18 studies, treatment was initiated after extubation. In the remaining studies, participants were not previously mechanically ventilated. HFNC versus standard oxygen therapy HFNC may lead to less treatment failure as indicated by escalation to alternative types of oxygen therapy (risk ratio (RR) 0.62, 95% confidence interval (CI) 0.45 to 0.86; 15 studies, 3044 participants; low-certainty evidence). HFNC probably makes little or no difference in mortality when compared with standard oxygen therapy (RR 0.96, 95% CI 0.82 to 1.11; 11 studies, 2673 participants; moderate-certainty evidence). HFNC probably results in little or no difference to cases of pneumonia (RR 0.72, 95% CI 0.48 to 1.09; 4 studies, 1057 participants; moderate-certainty evidence), and we were uncertain of its effect on nasal mucosa or skin trauma (RR 3.66, 95% CI 0.43 to 31.48; 2 studies, 617 participants; very low-certainty evidence). We found low-certainty evidence that HFNC may make little or no difference to the length of ICU stay according to the type of respiratory support used (MD 0.12 days, 95% CI -0.03 to 0.27; 7 studies, 1014 participants). We are uncertain whether HFNC made any difference to the ratio of partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO2/FiO2) within 24 hours of treatment (MD 10.34 mmHg, 95% CI -17.31 to 38; 5 studies, 600 participants; very low-certainty evidence). We are uncertain whether HFNC made any difference to short-term comfort (MD 0.31, 95% CI -0.60 to 1.22; 4 studies, 662 participants, very low-certainty evidence), or to long-term comfort (MD 0.59, 95% CI -2.29 to 3.47; 2 studies, 445 participants, very low-certainty evidence). HFNC versus NIV or NIPPV We found no evidence of a difference between groups in treatment failure when HFNC were used post-extubation or without prior use of mechanical ventilation (RR 0.98, 95% CI 0.78 to 1.22; 5 studies, 1758 participants; low-certainty evidence), or in-hospital mortality (RR 0.92, 95% CI 0.64 to 1.31; 5 studies, 1758 participants; low-certainty evidence). We are very uncertain about the effect of using HFNC on incidence of pneumonia (RR 0.51, 95% CI 0.17 to 1.52; 3 studies, 1750 participants; very low-certainty evidence), and HFNC may result in little or no difference to barotrauma (RR 1.15, 95% CI 0.42 to 3.14; 1 study, 830 participants; low-certainty evidence). HFNC may make little or no difference to the length of ICU stay (MD -0.72 days, 95% CI -2.85 to 1.42; 2 studies, 246 participants; low-certainty evidence). The ratio of PaO2/FiO2 may be lower up to 24 hours with HFNC use (MD -58.10 mmHg, 95% CI -71.68 to -44.51; 3 studies, 1086 participants; low-certainty evidence). We are uncertain whether HFNC improved short-term comfort when measured using comfort scores (MD 1.33, 95% CI 0.74 to 1.92; 2 studies, 258 participants) and responses to questionnaires (RR 1.30, 95% CI 1.10 to 1.53; 1 study, 168 participants); evidence for short-term comfort was very low certainty. No studies reported on nasal mucosa or skin trauma.

AUTHORS' CONCLUSIONS

HFNC may lead to less treatment failure when compared to standard oxygen therapy, but probably makes little or no difference to treatment failure when compared to NIV or NIPPV. For most other review outcomes, we found no evidence of a difference in effect. However, the evidence was often of low or very low certainty. We found a large number of ongoing studies; including these in future updates could increase the certainty or may alter the direction of these effects.

High-flow nasal cannula oxygen versus conventional oxygen for hypercapnic chronic obstructive pulmonary disease: A meta-analysis of randomized controlled trials

INTRODUCTION

Low-concentration oxygen is an established way for the treatment of chronic obstructive pulmonary disease (COPD) with Type II respiratory failure. Hypercapnia can complicate both COPD exacerbations and stable COPD. Treating with noninvasive ventilation (NIV) can reduce carbon dioxide tension in arterial (PaCO₂ ) in hypercapnic COPD. As an open system, high-flow nasal cannula oxygen (HFNC) is easy to tolerate and use. More researches are needed to focus on how HFNC is used to treat COPD patients with hypercapnic respiratory failure.

METHODS

The Cochrane Library, Medline, EMBASE, and CINAHL database were retrieved from inception to October 2019. Eligible trials were clinical randomized controlled trials comparing the effects of HFNC and conventional oxygen on hypercapnic COPD patients. Two researchers assessed the quality of each study and extracted the data into RevMan 5.3 independently. The primary outcome was PaCO₂ and the secondary outcome was PaO₂ .

RESULTS

Four RCTs with 329 patients were included. The research results indicated that PaCO₂ in the HFNC group was similar to the conventional oxygen group. No significant difference were observed in PaCO₂ (MD -0.98, CI: -2.67 to 0.71, Z = 1.14, p = 0.25) and PaO₂ (MD -0.72, CI: -6.99 to 5.55, Z = 0.23, p = 0.82) between the HFNC group and conventional oxygen group.

CONCLUSIONS

Our meta-analysis showed no difference in PO₂ and PCO₂ between the HFNC and conventional oxygen. But we should treat this conclusion with caution because the number of studies and participants is small and, there is heterogeneity in the PaO₂ and PCO₂ measurements between stable and AECOPD.

Prolonged Weaning: S2k Guideline Published by the German Respiratory Society

Mechanical ventilation (MV) is an essential part of modern intensive care medicine. MV is performed in patients with severe respiratory failure caused by respiratory muscle insufficiency and/or lung parenchymal disease; that is, when other treatments such as medication, oxygen administration, secretion management, continuous positive airway pressure (CPAP), or nasal high-flow therapy have failed. MV is required for maintaining gas exchange and allows more time to curatively treat the underlying cause of respiratory failure. In the majority of ventilated patients, liberation or "weaning" from MV is routine, without the occurrence of any major problems. However, approximately 20% of patients require ongoing MV, despite amelioration of the conditions that precipitated the need for it in the first place. Approximately 40-50% of the time spent on MV is required to liberate the patient from the ventilator, a process called "weaning". In addition to acute respiratory failure, numerous factors can influence the duration and success rate of the weaning process; these include age, comorbidities, and conditions and complications acquired during the ICU stay. According to international consensus, "prolonged weaning" is defined as the weaning process in patients who have failed at least 3 weaning attempts, or require more than 7 days of weaning after the first spontaneous breathing trial (SBT). Given that prolonged weaning is a complex process, an interdisciplinary approach is essential for it to be successful. In specialised weaning centres, approximately 50% of patients with initial weaning failure can be liberated from MV after prolonged weaning. However, the heterogeneity of patients undergoing prolonged weaning precludes the direct comparison of individual centres. Patients with persistent weaning failure either die during the weaning process, or are discharged back to their home or to a long-term care facility with ongoing MV. Urged by the growing importance of prolonged weaning, this Sk2 Guideline was first published in 2014 as an initiative of the German Respiratory Society (DGP), in conjunction with other scientific societies involved in prolonged weaning. The emergence of new research, clinical study findings and registry data, as well as the accumulation of experience in daily practice, have made the revision of this guideline necessary. The following topics are dealt with in the present guideline: Definitions, epidemiology, weaning categories, underlying pathophysiology, prevention of prolonged weaning, treatment strategies in prolonged weaning, the weaning unit, discharge from hospital on MV, and recommendations for end-of-life decisions. Special emphasis was placed on the following themes: (1) A new classification of patient sub-groups in prolonged weaning. (2) Important aspects of pulmonary rehabilitation and neurorehabilitation in prolonged weaning. (3) Infrastructure and process organisation in the care of patients in prolonged weaning based on a continuous treatment concept. (4) Changes in therapeutic goals and communication with relatives. Aspects of paediatric weaning are addressed separately within individual chapters. The main aim of the revised guideline was to summarize both current evidence and expert-based knowledge on the topic of "prolonged weaning", and to use this information as a foundation for formulating recommendations related to "prolonged weaning", not only in acute medicine but also in the field of chronic intensive care medicine. The following professionals served as important addressees for this guideline: intensivists, pulmonary medicine specialists, anaesthesiologists, internists, cardiologists, surgeons, neurologists, paediatricians, geriatricians, palliative care clinicians, rehabilitation physicians, intensive/chronic care nurses, physiotherapists, respiratory therapists, speech therapists, medical service of health insurance, and associated ventilator manufacturers.

High-Flow Nasal Cannula Therapy for Exertional Dyspnea in Patients with Cancer: A Pilot Randomized Clinical Trial

BACKGROUND

Exertional dyspnea is common in patients with cancer and limits their function. The impact of high-flow nasal cannula on exertional dyspnea in nonhypoxemic patients is unclear. In this double-blind, parallel-group, randomized trial, we assessed the effect of flow rate (high vs. low) and gas (oxygen vs. air) on exertional dyspnea in nonhypoxemic patients with cancer.

PATIENTS AND METHODS

Patients with cancer with oxygen saturation >90% at rest and exertion completed incremental and constant work (80% maximal) cycle ergometry while breathing low-flow air at 2 L/minute. They were then randomized to receive high-flow oxygen, high-flow air, low-flow oxygen, or low-flow air while performing symptom-limited endurance cycle ergometry at 80% maximal. The primary outcome was modified 0-10 Borg dyspnea intensity scale at isotime. Secondary outcomes included dyspnea unpleasantness, exercise time, and adverse events.

RESULTS

Seventy-four patients were enrolled, and 44 completed the study (mean age 63; 41% female). Compared with low-flow air at baseline, dyspnea intensity was significantly lower at isotime with high-flow oxygen (mean change, -1.1; 95% confidence interval [CI], -2.1, -0.12) and low-flow oxygen (-1.83; 95% CI, -2.7, -0.9), but not high-flow air (-0.2; 95% CI, -0.97, 0.6) or low-flow air (-0.5; 95% CI, -1.3, 0.4). Compared with low-flow air, high-flow oxygen also resulted in significantly longer exercise time (difference + 2.5 minutes, p = .009), but not low-flow oxygen (+0.39 minutes, p = .65) or high-flow air (+0.63 minutes, p = .48). The interventions were well tolerated without significant adverse effects.

CONCLUSION

Our preliminary findings support that high-flow oxygen improved both exertional dyspnea and exercise duration in nonhypoxemic patients with cancer. (ClinicalTrials.gov ID: NCT02357134).

IMPLICATIONS FOR PRACTICE

In this four-arm, double-blind, randomized clinical trial examining the role of high-flow nasal cannula on exertional dyspnea in patients with cancer without hypoxemia, high-flow oxygen, but not high-flow air, resulted in significantly lower dyspnea scores and longer exercise time. High-flow oxygen delivered by high-flow nasal cannula devices may improve clinically relevant outcomes even in patients without hypoxemia.

High-flow nasal cannula therapy for acute respiratory failure in patients with chest trauma: A single-center retrospective study

PURPOSE

This retrospective study was performed to investigate the utility of high-flow nasal cannula (HFNC) therapy in patients with chest trauma and identify the risk factors associated with treatment failure.

MATERIALS AND METHODS

We identified 44 acute respiratory failure patients with chest trauma who received HFNC therapy between June 2016 and March 2019 at the Fourth Affiliated Hospital of Nantong University. According to their response to HFNC therapy, the patients were divided into success and failure groups. Their medical records were reviewed retrospectively to identify useful risk factors for HFNC treatment failure.

RESULTS

Of the 44 patients, 25 and 19 patients were assigned to the HFNC success and failure groups, respectively. Compared with the success group, the failure group had a significantly higher rate of multiple rib fractures/flail chest (P = 0.035), higher Thoracic Trauma Severity Score (TTSS) (P = 0.001) and significantly longer ICU stay (P = 0.006) and hospital stay (P = 0.001). The mortality rate of the failure group was higher than that of the success group, but there was no significant difference (P = 0.414). High TTSS was a significant risk factor for treatment failure. The AUC of TTSS was 0.793. The cut-off value for TTSS was 14 points (sensitivity: 0.68, specificity: 0.84).

CONCLUSIONS

HFNC therapy was safe and effective in patients with chest trauma, and more than 50% of the patients successfully recovered from acute respiratory failure without invasive ventilation. A high TTSS could be a significant risk factor for HFNC treatment failure and had a high predictive performance.

A Rationale for Use of High Flow Nasal Cannula for Select Patients With Suspected or Confirmed Severe Acute Respiratory Syndrome Coronavirus-2 Infection

Infection with the novel 2019 coronavirus (SARS-CoV-2) is associated with the development of a viral pneumonia with severe hypoxemia and respiratory failure. In many cases these patients will require mechanical ventilation; but in others the severity of disease is significantly less and may not need invasive support. High flow nasal cannula (HFNC) is a widely used modality of delivering high concentrations of oxygen and airflow to patients with hypoxemic respiratory failure, but its use in patients with SARS-CoV-2 is poorly described. Concerns with use of HFNC have arisen including aerosolization of viral particles to healthcare workers (HCW) to delaying intubation and potentially worsening of outcomes. However, use of HFNC in other coronavirus pandemics and previous experimental evidence suggest HFNC is low risk and may be effective in select patients infected with SARS-CoV-2. With the significant increase in resource utilization in care of patients with SARS-CoV-2, identification of those that may benefit from HFNC allowing allocation of ventilators to those more critically ill is of significant importance. In this manuscript, we review pertinent literature regarding the use of HFNC in the current SARS-CoV-2 pandemic and address many concerns regarding its use.

Use of nasal high flow oxygen during acute respiratory failure

Nasal high flow (NHF) has gained popularity among intensivists to manage patients with acute respiratory failure. An important literature has accompanied this evolution. In this review, an international panel of experts assessed potential benefits of NHF in different areas of acute respiratory failure management. Analyses of the physiological effects of NHF indicate flow-dependent improvement in various respiratory function parameters. These beneficial effects allow some patients with severe acute hypoxemic respiratory failure to avoid intubation and improve their outcome. They require close monitoring to not delay intubation. Such a delay may worsen outcome. The ROX index may help clinicians decide when to intubate. In immunocompromised patients, NHF reduces the need for intubation but does not impact mortality. Beneficial physiological effects of NHF have also been reported in patients with chronic respiratory failure, suggesting a possible indication in acute hypercapnic respiratory failure. When intubation is required, NHF can be used to pre-oxygenate patients either alone or in combination with non-invasive ventilation (NIV). Similarly, NHF reduces reintubation alone in low-risk patients and in combination with NIV in high-risk patients. NHF may be used in the emergency department in patients who would not be offered intubation and can be better tolerated than NIV.

COVID-19 Infection: Implications for Perioperative and Critical Care Physicians

Healthcare systems worldwide are responding to Coronavirus Disease 2019 (COVID-19), an emerging infectious syndrome caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus. Patients with COVID-19 can progress from asymptomatic or mild illness to hypoxemic respiratory failure or multisystem organ failure, necessitating intubation and intensive care management. Healthcare providers, and particularly anesthesiologists, are at the frontline of this epidemic, and they need to be aware of the best available evidence to guide therapeutic management of patients with COVID-19 and to keep themselves safe while doing so. Here, the authors review COVID-19 pathogenesis, presentation, diagnosis, and potential therapeutics, with a focus on management of COVID-19-associated respiratory failure. The authors draw on literature from other viral epidemics, treatment of acute respiratory distress syndrome, and recent publications on COVID-19, as well as guidelines from major health organizations. This review provides a comprehensive summary of the evidence currently available to guide management of critically ill patients with COVID-19.

Therapeutic effect of high-flow nasal cannula on severe COVID-19 patients in a makeshift intensive-care unit: A case report

INTRODUCTION

Several intensive-care units (ICUs) in Wuhan are nonstandard wards that were repurposed from general wards. Considering the shortage of medical resources and the need to prevent nosocomic infection, the respiratory-treatment strategy in these nonstandard ICUs is different from those in general wards and standard ICUs. High-flow nasal cannula (HFNC) plays an important role in nonstandard ICUs and is beneficial to the patients therein.

PATIENT CONCERNS

In this study, we analyzed four cases of HFNC-treated patients with severe coronavirus disease 2019 (COVID-19) in a makeshift ICU and summarized our experience.

DIAGNOSES

Four patients diagnosed with COVID-19 according to World Health Organization (WHO) interim guidance were admitted to the makeshift ICU.

INTERVENTIONS

All patients had oxygen treatment with HFNC, as well as regular treatment of antivirals and traditional Chinese medicine.

OUTCOMES

Two patients survived after treatment, while the other two died from acute respiratory distress syndrome (ARDS) and heart failure, respectively.

CONCLUSION

Patients with severe and critical COVID-19 often have poor prognoses after mechanical ventilation, exhibiting corresponding complications such as ventilator-associated pneumonia and deep-vein thrombosis, which significantly prolongs length of stay in the ICU. HFNC could prevent intubation in some patients, thereby avoiding the above complications; however, this needs confirmation in further clinical studies. This treatment reduced difficulty and workloads for healthcare professionals, had good tolerability for patients, might not significantly increase the risk of infection for healthcare professionals, and do not require additional preventive measures against nosocomic infection. HFNC treatment has its advantages in providing oxygen therapy in COVID-19, but healthcare professionals should still pay close attention to changes in patients' oxygenation rates and respiratory frequency.

High-flow nasal cannula oxygen therapy as an emerging option for respiratory failure: the present and the future

Conventional oxygen therapy (COT) and noninvasive ventilation (NIV) have been considered for decades as frontline treatment for acute or chronic respiratory failure. However, COT can be insufficient in severe hypoxaemia whereas NIV, although highly effective, is poorly tolerated by patients and its use requires a specific expertise. High-flow nasal cannula (HFNC) is an emerging technique, designed to provide oxygen at high flows with an optimal degree of heat and humidification, which is well tolerated and easy to use in all clinical settings. Physiologically, HFNC reduces the anatomical dead space and improves carbon dioxide wash-out, reduces the work of breathing, and generates a positive end-expiratory pressure and a constant fraction of inspired oxygen. Clinically, HFNC effectively reduces dyspnoea and improves oxygenation in respiratory failure from a variety of aetiologies, thus avoiding escalation to more invasive supports. In recent years it has been adopted to treat de novo hypoxaemic respiratory failure, exacerbation of chronic obstructive pulmonary disease (COPD), postintubation hypoxaemia and used for palliative respiratory care. While the use of HFNC in acute respiratory failure is now routine as an alternative to COT and sometimes NIV, new potential applications in patients with chronic respiratory diseases (e.g. domiciliary treatment of patients with stable COPD), are currently under evaluation and will become a topic of great interest in the coming years.

Preparing your intensive care unit for the COVID-19 pandemic: practical considerations and strategies

The coronavirus disease 2019 (COVID-19) has rapidly evolved into a worldwide pandemic. Preparing intensive care units (ICU) is an integral part of any pandemic response. In this review, we discuss the key principles and strategies for ICU preparedness. We also describe our initial outbreak measures and share some of the challenges faced. To achieve sustainable ICU services, we propose the need to 1) prepare and implement rapid identification and isolation protocols, and a surge in ICU bed capacity; (2) provide a sustainable workforce with a focus on infection control; (3) ensure adequate supplies to equip ICUs and protect healthcare workers; and (4) maintain quality clinical management, as well as effective communication.

Use of High-Flow Nasal Cannula for Immunocompromise and Acute Respiratory Failure: A Systematic Review and Meta-Analysis

BACKGROUND

Acute respiratory failure (ARF) is a common cause of emergency department (ED) and intensive care unit (ICU) admissions. High-flow nasal cannula oxygen therapy (HFNC) is widely used for patients with ARF.

OBJECTIVE

Our aim was to evaluate the latest evidence regarding the application of HFNC in immunocompromised patients with ARF.

METHODS

We searched PubMed, Embase, and Cochrane databases from inception to January 2019. The primary outcome was short-term mortality and the secondary outcomes were intubation rate and length of ICU stay.

RESULTS

Eight studies involving 2,179 immunocompromised subjects with ARF were included. No significant differences for short-term mortality were observed when comparing HFNC with conventional oxygen therapy (COT) (risk ratio [RR] 0.89; 95% confidence interval [CI] 0.73 to 1.09; p = 0.25, I² = 47%) and with noninvasive ventilation (NIV) (RR 0.66; 95% CI 0.37 to 1.18; p = 0.16, I² = 58%). Lower intubation rates were found when comparing HFNC with COT (RR 0.89; 95% CI 0.80 to 0.99; p = 0.03, I² = 0%) and no significant difference was found between HFNC and NIV (RR 0.74; 95% CI 0.46 to 1.19; p = 0.22, I² = 67%). The length of ICU stay was similar when comparing HFNC with COT (mean difference [MD] 0.59; 95% CI -1.68 to 2.85; p = 0.61, I² = 56%), but was significantly shorter when HFNC was compared with NIV (MD -2.13; 95% CI -3.98 to -0.29; p = 0.02, I² = 0%).

CONCLUSIONS

There was no significant difference in short-term mortality with use of HFNC when compared with COT or NIV for immunocompromised patients with ARF. A lower intubation rate than COT and a shorter length of ICU stay than NIV were observed in the HFNC group.

High-flow nasal cannula oxygen therapy in idiopathic pulmonary fibrosis patients with respiratory failure

Background

High-flow nasal cannula (HFNC) oxygen therapy is widely applied in idiopathic pulmonary fibrosis (IPF) patients with acute respiratory failure (ARF); however, its advantages over mechanical ventilation (MV) remain unclear. We aimed to compare the clinical outcomes of HFNC oxygen therapy and MV in IPF patients with respiratory failure.

Methods

A retrospective descriptive study of patients with IPF admitted between January 2015 and December 2017 who underwent HFNC oxygen therapy or MV during hospitalization was conducted. The primary outcome was the comparison of in-hospital mortality among HFNC only group, MV with prior HFNC group, and MV only group.

Results

A total of 61 patients with IPF and ARF were included in the current study. Forty-five patients received HFNC oxygen therapy without endotracheal intubation and 16 received MV. The overall hospital mortality rate was 59.0%, of which 53.3% was for HFNC oxygen therapy and 55.6% (5/9) for MV only group (P=1.000). Although no significant difference in the mortality rate was observed among three groups, that of MV with prior HFNC oxygen therapy (n=7) was 100% (P=0.064). Additionally, the HFNC oxygen therapy group showed shorter length of hospital and ICU stay than the MV group (P<0.001).

Conclusions

Patients with IPF and ARF who received MV with prior HFNC oxygen therapy showed increased mortality rate than those who received HFNC only oxygen therapy or MV. Considering the complication rate of MV, need for lung transplantation, and the will to undergo end-of-life care, a proper transition from HFNC oxygen therapy to MV should be planned cautiously.

High-Flow Nasal Cannula Oxygen in Patients with Acute Respiratory Failure and Do-Not-Intubate or Do-Not-Resuscitate Orders: A Systematic Review

BACKGROUND AND OBJECTIVES

High-flow nasal cannula (HFNC) oxygen may provide tailored benefits in patients with preset treatment limitations. The objective of this study was to assess the effectiveness of HFNC oxygen in patients with do-not-intubate (DNI) and/or do-not-resuscitate (DNR) orders.

METHODS

We conducted a systematic review of interventional and observational studies. A search was performed using MEDLINE, EMBASE, CINAHL, Scopus, and Web of Science, from inception to October 15, 2018.

RESULTS

We included six studies evaluating 293 patients. All studies had a high risk of bias. The hospital mortality rates of patients with DNI and/or DNR orders receiving HFNC oxygen were variable and ranged from 40% to 87%. In two before and after studies, the initiation of HFNC oxygen was associated with improved oxygenation and reduced respiratory rates. One comparative study found no difference in dyspnea reduction or morphine doses between patients using HFNC oxygen versus conventional oxygen. No studies evaluated quality of life in survivors or quality of death in nonsurvivors. HFNC was generally well tolerated with few adverse events identified.

CONCLUSIONS

While HFNC oxygen remains a viable treatment option for hospitalized patients who have acute respiratory failure and a DNI and/or DNR order, there is a paucity of high-quality, comparative, effectiveness data to guide the usage of HFNC oxygen compared with other treatments, such as noninvasive ventilation, conventional oxygen, and palliative opioids.

Use High-Flow Nasal Cannula for Acute Respiratory Failure Patients in the Emergency Department: A Meta-Analysis Study

Objective

To evaluate the efficacy of high-flow nasal cannula (HFNC) therapy compared with conventional oxygen therapy (COT) or noninvasive ventilation (NIV) for the treatment of acute respiratory failure (ARF) in emergency departments (EDs).

Method

We comprehensively searched 3 databases (PubMed, EMBASE, and the Cochrane Library) for articles published from database inception to 12 July 2019. This study included only randomized controlled trials (RCTs) that were conducted in EDs and compared HFNC therapy with COT or NIV. The primary outcome was the intubation rate. The secondary outcomes were the mortality rate, intensive care unit (ICU) admission rate, ED discharge rate, need for escalation, length of ED stay, length of hospital stay, and patient dyspnea and comfort scores.

Result

Five RCTs (n = 775) were included. There was a decreasing trend regarding the application of HFNC therapy and the intubation rate, but the difference was not statistically significant (RR, 0.53; 95% CI, 0.26–1.09; p=0.08; I² = 0%). We found that compared with patients who underwent COT, those who underwent HFNC therapy had a reduced need for escalation (RR, 0.41; 95% CI, 0.22–0.78; p=0.006; I² = 0%), reduced dyspnea scores (MD −0.82, 95% CI −1.45 to −0.18), and improved comfort (SMD −0.76 SD, 95% CI −1.01 to −0.51). Compared with the COT group, the HFNC therapy group had a similar mortality rate (RR, 1.25; 95% CI, 0.79–1.99; p=0.34; I² = 0%), ICU admission rate (RR, 1.11; 95% CI, 0.58–2.12; p=0.76; I² = 0%), ED discharge rate (RR, 1.04; 95% CI, 0.63–1.72; p=0.87; I² = 0%), length of ED stay (MD 1.66, 95% CI −0.95 to 4.27), and hospital stay (MD 0.9, 95% CI −2.06 to 3.87).

Conclusion

Administering HFNC therapy in ARF patients in EDs might decrease the intubation rate compared with COT. In addition, it can decrease the need for escalation, decrease the patient's dyspnea level, and increase the patient's comfort level compared with COT.

Benefits of non-invasive ventilation in acute hypercapnic respiratory failure

Non-invasive ventilation (NIV) with bilevel positive airway pressure is a non-invasive technique, which refers to the provision of ventilatory support through the patient's upper airway using a mask or similar device. This technique is successful in correcting hypoventilation. It has become widely accepted as the standard treatment for patients with hypercapnic respiratory failure (HRF). Since the 1980s, NIV has been used in intensive care units and, after initial anecdotal reports and larger series, a number of randomized trials have been conducted. Data from these trials have shown that NIV is a valuable treatment for HRF. This review aims to explore the principal areas in which NIV can be useful, focusing particularly on patients with acute HRF (AHRF). We will update the evidence base with the goal of supporting clinical practice. We provide a practical description of the main indications for NIV in AHRF and identify the group of patients with hypercapnic failure who will benefit most from the application of NIV.

High-flow nasal cannula in adults with acute respiratory failure and after extubation: a systematic review and meta-analysis

Background

High-flow nasal cannula (HFNC) can be used as an initial support strategy for patients with acute respiratory failure (ARF) and after extubation. However, no clear evidence exists to support or oppose HFNC use in clinical practice. We summarized the effects of HFNC, compared to conventional oxygen therapy (COT) and noninvasive ventilation (NIV), on important outcomes including treatment failure and intubation/reintubation rates in adult patients with ARF and after extubation.

Methods

We searched 4 electronic databases (Pubmed, EMBASE, Scopus, and Web of Science) to identify randomized controlled trials (RCTs) comparing the effects of HFNC with either COT or NIV on rates of 1) treatment failure and 2) intubation/reintubation in adult critically ill patients.

Results

We identified 18 RCTs (n = 4251 patients) in pooled analyses. As a primary mode of support, HFNC treatment reduced the risk of treatment failure [Odds Ratio (OR) 0.65; 95% confidence interval (CI) 0.43–0.98; p = 0.04; I² = 32%] but had no effect on preventing intubation (OR, 0.74; 95%CI 0.45–1.21; p = 0.23; I² = 0%) compared to COT. When used after extubation, HFNC (vs. COT) treatment significantly decreased reintubation rate (OR 0.46; 95%CI 0.33–0.63; p < 0.00001; I² = 30%) and extubation failure (OR 0.43; 95%CI 0.25–0.73; p = 0.002; I² = 66%). Compared to NIV, HFNC significantly reduced intubation rate (OR 0.57; 95%CI 0.36–0.92; p = 0.02; I² = 0%) when used as initial support, but did no favorably impact clinical outcomes post extubation in few trials.

Conclusions

HFNC was superior to COT in reducing treatment failure when used as a primary support strategy and in reducing rates of extubation failure and reintubation when used after extubation. In few trials, HFNC reduced intubation rate compared to NIV when used as initial support but demonstrated no beneficial effects after extubation.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0908-7) contains supplementary material, which is available to authorized users.

Approaches and techniques to avoid development or progression of acute respiratory distress syndrome

PURPOSE OF REVIEW

Despite major improvement in ventilation strategies, hospital mortality and morbidity of the acute respiratory distress syndrome (ARDS) remain high. A lot of therapies have been shown to be ineffective for established ARDS. There is a growing interest in strategies aiming at avoiding development and progression of ARDS.

RECENT FINDINGS

Recent advances in this field have explored identification of patients at high-risk, nonspecific measures to limit the risks of inflammation, infection and fluid overload, prevention strategies of ventilator-induced lung injury and patient self-inflicted lung injury, and pharmacological treatments.

SUMMARY

There is potential for improvement in the management of patients admitted to intensive care unit to reduce ARDS incidence. Apart from nonspecific measures, prevention of ventilator-induced lung injury and patient self-inflicted lung injury are of major importance.

Industry-funded versus non-profit-funded critical care research: a meta-epidemiological overview

Purpose

To study the landscape of funding in intensive care research and assess whether the reported outcomes of industry-funded randomized controlled trials (RCTs) are more favorable.

Methods

We systematically assembled meta-analyses evaluating any type of intervention in the critical care setting and reporting the source of funding for each included RCT. Furthermore, when the intervention was a drug or biologic, we searched also the original RCT articles, when their funding information was unavailable in the meta-analysis. We then qualitatively summarized the sources of funding. For binary outcomes, separate summary odds ratios were calculated for trials with and without industry funding. We then calculated the ratio of odds ratios (RORs) and the summary ROR (sROR) across topics. ROR < 1 implies that the experimental intervention is relatively more favorable in trials with industry funding compared with trials without industry funding. For RCTs included in the ROR analysis, we also examined the conclusions of their abstract.

Results

Across 67 topics with 568 RCTs, 88 were funded by industry and another 73 had both industry and non-profit funding. Across 33 topics with binary outcomes, the sROR was 1.10 [95% CI (0.96–1.26), I² = 1%]. Conclusions were not significantly more commonly unfavorable for the experimental arm interventions in industry-funded trials (21.3%) compared with trials without industry funding (18.2%).

Conclusion

Industry-funded RCTs are the minority in intensive care. We found no evidence that industry-funded trials in intensive care yield more favorable results or are less likely to reach unfavorable conclusions.

Electronic supplementary material

The online version of this article (10.1007/s00134-018-5325-3) contains supplementary material, which is available to authorized users.

A Systematic Review of the High-flow Nasal Cannula for Adult Patients

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2018. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2018. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

High flow nasal oxygen therapy utilization: 7-year experience at a community teaching hospital

OBJECTIVE

To examine the use of high flow nasal cannula oxygen therapy (HFNC) between 2008 and 2014 in patients 18 years or older at a community teaching hospital.

METHODS

Yearly utilization rates of HFNC, noninvasive ventilation (NIV) and invasive mechanical ventilation (IMV) were calculated among admissions with a set of cardiopulmonary diagnoses (heart failure, COPD, asthma or pneumonia).

RESULTS

Among the 41,711 admissions with at least one of the above cardiopulmonary condition, HFNC was utilized in 1,128 or 27.0/1000; NIV was used in an average of 169/1000 and IMV in 231/1000. HFNC was accompanied by IMV or NIV 71.3% of the time. From 2008 to 2014 HFNC utilization increased an average of 17.5% annually; NIV increased by 10.2% annually while IMV's utilization increased by 1.6% annually. The highest rate of change in HFNC use was among admissions with pneumonia and those with COPD.

CONCLUSION

HFNC utilization increased steadily over a 7-year period at our hospital. Frequently, HFNC therapy was used in combination with other ventilatory modes to support patients' respiration. Similar with other technologies in healthcare, the uptake of HFNC has preceded the evidence from robust clinical trials.

High-flow nasal cannula oxygen therapy versus conventional oxygen therapy in patients with acute respiratory failure: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Acute respiratory failure (ARF) is a common and life-threatening medical emergency in patients admitted to the hospital. Currently, there is a lack of large-scale evidence on the use of high-flow nasal cannulas (HFNC) in patients with ARF. In this systematic review and meta-analysis, we evaluated whether there were differences between HFNC therapy and conventional oxygen therapy (COT) for treating patients with ARF.

METHODS

The EMBASE, Medline, and Wanfang databases and the Cochrane Library were searched. Two investigators independently collected the data and assessed the quality of each study. Randomized controlled trials that compared HFNC therapy with COT in patients with ARF were included. RevMan 5.3 was used to conduct the meta-analysis.

RESULTS

Four studies that involved 703 patients with ARF were included, with 371 patients in the HFNC group and 332 patients in the COT group. In the overall estimates, there were no significant differences between the HFNC and COT groups in the rates of escalation of respiratory support (RR, 0.68; 95% CI, 0.37, 1.27; z = 1.20, P = 0.23), intubation (RR, 0.74; 95% CI, 0.55, 1.00; z = 1.95, P = 0.05), mortality (RR, 0.82; 95% CI, 0.36, 1.88; z = 0.47, P = 0.64), or ICU transfer (RR, 1.09; 95% CI, 0.57, 2.09; z = 0.26, P = 0.79) during ARF treatment. However, the subgroup analysis showed that HFNC therapy may decrease the rate of escalation of respiratory support (RR, 0.71; 95% CI, 0.53, 0.97; z = 2.15, P = 0.03) and the intubation rate (RR, 0.71; 95% CI, 0.53, 0.97; z = 2.15, P = 0.03) when ARF patients were treated with HFNC therapy for ≥24 h compared with COT.

CONCLUSIONS

HFNC therapy was similar to COT in ARF patients. The subgroup analysis showed that HFNC therapy may decrease the rate of escalation of respiratory support and the intubation rate when ARF patients were treated with HFNC for ≥24 h compared with COT. Further high-quality, large-scale studies are needed to confirm our results.

Cost-effectiveness analysis of the use of high-flow oxygen through nasal cannula in intensive care units in NHS England

OBJECTIVE

To estimate the cost-effectiveness of Nasal High Flow (NHF) in the intensive care unit (ICU) compared with standard oxygen or non-invasive ventilation (NIV) from a UK NHS perspective.

METHODS

Three cost-effectiveness models were developed to reflect scenarios of NHF use: first-line therapy (pre-intubation model); post-extubation in low-risk, and high-risk patients. All models used randomized control trial data on the incidence of intubation/re-intubation, events leading to intubation/re-intubation, mortality and complications. NHS reference costs were primarily used. Sensitivity analyses were conducted.

RESULTS

When used as first-line therapy, Optiflow™ NHF gives an estimated cost-saving of £469 per patient compared with standard oxygen and £611 versus NIV. NHF cost-savings for high severity sub-group were £727 versus standard oxygen, and £1,011 versus NIV. For low-risk post-intubation patients, NHF generates estimated cost-saving of £156 versus standard oxygen. NHF decreases the number of re-intubations required in these scenarios. Results were robust in most sensitivity analyses. For high-risk post-intubation patients, NHF cost-savings were £104 versus NIV. NHF results in a non-significant increase in re-intubations required. However, reduction in respiratory failure offsets this.

CONCLUSIONS

For patients in ICU who are at risk of intubation or re-intubation, NHF cannula is likely to be cost-saving.

High-flow oxygen via nasal cannulae in patients with acute hypoxemic respiratory failure: a systematic review and meta-analysis

BACKGROUND

We performed a systematic review and meta-analysis to evaluate the efficacy and safety of high-flow oxygen via nasal cannulae (HFNC) compared to non-invasive ventilation (NIV) and/or standard oxygen in patients with acute, hypoxemic respiratory failure.

METHODS

We reviewed randomized controlled trials from CENTRAL, EMBASE, MEDLINE, Scopus and the International Clinical Trials Registry Platform (inception to February 2016), conference proceedings, and relevant article reference lists. Two reviewers independently screened and extracted trial-level data from trials investigating HFNC in patients with acute, hypoxemic respiratory failure. Internal validity was assessed in duplicate using the Cochrane Risk of Bias tool. The strength of evidence was assessed in duplicate using the Grading of Recommendations Assessment, Development and Evaluation framework. Our primary outcome was mortality. Secondary outcomes included dyspnea, PaO2:FiO2 ratio, PaCO2, and pH. Safety outcomes included respiratory arrest, intubation, delirium, and skin breakdown.

RESULTS

From 2023 screened citations, we identified seven trials (1771 patients) meeting inclusion criteria. All trials were at high risk of bias due to lack of blinding. There was no evidence for a mortality difference in patients receiving HFNC vs. NIV and/or standard oxygen (RR 1.01, 95% CI 0.69 to 1.48, I 2 = 63%, five trials, 1629 patients). In subgroup analyses of HFNC compared to NIV or standard oxygen individually, mortality differences were not observed. Measures of patient tolerability were heterogeneous. The PaO2:FiO2 ratio at 6-12 h was significantly lower in patients receiving oxygen via HFNC compared to NIV or standard oxygen for hypoxemic respiratory failure (MD - 53.34, 95% CI - 71.95 to - 34.72, I 2 = 61%, 1143 patients). There were no differences in pH, PaCO2, or rates of intubation or cardio-respiratory arrest. Delirium and skin breakdown were infrequently reported in included trials.

CONCLUSIONS

In patients with acute hypoxemic respiratory failure HFNC was not associated with a difference in mortality compared to NIV or standard oxygen. Secondary outcomes including dyspnea, tolerance, and safety were not systematically reported. Residual heterogeneity and variable reporting of secondary outcomes limit the conclusions that can be made in this review. Prospective trials designed to evaluate the efficacy and safety of HFNC in patients with acute hypoxemic respiratory failure are required.

High-flow nasal cannula oxygen therapy is superior to conventional oxygen therapy but not to noninvasive mechanical ventilation on intubation rate: a systematic review and meta-analysis

Background

High-flow nasal cannula oxygen (HFNC) is a relatively new therapy used in adults with respiratory failure. Whether it is superior to conventional oxygen therapy (COT) or to noninvasive mechanical ventilation (NIV) remains unclear. The aim of the present study was to investigate whether HFNC was superior to either COT or NIV in adult acute respiratory failure patients.

Methods

A review of the literature was conducted from the electronic databases from inception up to 20 October 2016. Only randomized clinical trials comparing HFNC with COT or HFNC with NIV were included. The intubation rate was the primary outcome; secondary outcomes included the mechanical ventilation rate, the rate of escalation of respiratory support and mortality.

Results

Eleven studies that enrolled 3459 patients (HFNC, n = 1681) were included. There were eight studies comparing HFNC with COT, two comparing HFNC with NIV, and one comparing all three. HFNC was associated with a significant reduction in intubation rate (OR 0.52, 95% CI 0.34 to 0.79, P = 0.002), mechanical ventilation rate (OR 0.56, 95% CI 0.33 to 0.97, P = 0.04) and the rate of escalation of respiratory support (OR 0.45, 95% CI 0.31 to 0.67, P < 0.0001) when compared to COT. There was no difference in mortality between HFNC and COT utilization (OR 1.01, 95% CI 0.67 to 1.53, P = 0.96). When HFNC was compared to NIV, there was no difference in the intubation rate (OR 0.96; 95% CI 0.66 to 1.39, P = 0.84), the rate of escalation of respiratory support (OR 1.00, 95% CI 0.77 to 1.28, P = 0.97) or mortality (OR 0.85, 95% CI 0.43 to 1.68, P = 0.65).

Conclusions

Compared to COT, HFNC reduced the rate of intubation, mechanical ventilation and the escalation of respiratory support. When compared to NIV, HFNC showed no better outcomes. Large-scale randomized controlled trials are necessary to prove our findings.

Trial registration

PROSPERO International prospective register of systematic reviews on May 25, 2016 registration no. CRD42016039581.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1760-8) contains supplementary material, which is available to authorized users.

High-flow nasal cannulae for respiratory support in adult intensive care patients

BACKGROUND

High-flow nasal cannulae (HFNC) deliver high flows of blended humidified air and oxygen via wide-bore nasal cannulae and may be useful in providing respiratory support for adult patients experiencing acute respiratory failure in the intensive care unit (ICU).

OBJECTIVES

We evaluated studies that included participants 16 years of age and older who were admitted to the ICU and required treatment with HFNC. We assessed the safety and efficacy of HFNC compared with comparator interventions in terms of treatment failure, mortality, adverse events, duration of respiratory support, hospital and ICU length of stay, respiratory effects, patient-reported outcomes, and costs of treatment.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 3), MEDLINE, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, Web of Science, proceedings from four conferences, and clinical trials registries; and we handsearched reference lists of relevant studies. We conducted searches from January 2000 to March 2016 and reran the searches in December 2016. We added four new studies of potential interest to a list of 'Studies awaiting classification' and will incorporate them into formal review findings during the review update.

SELECTION CRITERIA

We included randomized controlled studies with a parallel or cross-over design comparing HFNC use in adult ICU patients versus other forms of non-invasive respiratory support (low-flow oxygen via nasal cannulae or mask, continuous positive airway pressure (CPAP), and bilevel positive airway pressure (BiPAP)).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion, extracted data, and assessed risk of bias.

MAIN RESULTS

We included 11 studies with 1972 participants. Participants in six studies had respiratory failure, and in five studies required oxygen therapy after extubation. Ten studies compared HFNC versus low-flow oxygen devices; one of these also compared HFNC versus CPAP, and another compared HFNC versus BiPAP alone. Most studies reported randomization and allocation concealment inadequately and provided inconsistent details of outcome assessor blinding. We did not combine data for CPAP and BiPAP comparisons with data for low-flow oxygen devices; study data were insufficient for separate analysis of CPAP and BiPAP for most outcomes. For the primary outcomes of treatment failure (1066 participants; six studies) and mortality (755 participants; three studies), investigators found no differences between HFNC and low-flow oxygen therapies (risk ratio (RR), Mantel-Haenszel (MH), random-effects 0.79, 95% confidence interval (CI) 0.49 to 1.27; and RR, MH, random-effects 0.63, 95% CI 0.38 to 1.06, respectively). We used the GRADE approach to downgrade the certainty of this evidence to low because of study risks of bias and different participant indications. Reported adverse events included nosocomial pneumonia, oxygen desaturation, visits to general practitioner for respiratory complications, pneumothorax, acute pseudo-obstruction, cardiac dysrhythmia, septic shock, and cardiorespiratory arrest. However, single studies reported adverse events, and we could not combine these findings; one study reported fewer episodes of oxygen desaturation with HFNC but no differences in all other reported adverse events. We downgraded the certainty of evidence for adverse events to low because of limited data. Researchers noted no differences in ICU length of stay (mean difference (MD), inverse variance (IV), random-effects 0.15, 95% CI -0.03 to 0.34; four studies; 770 participants), and we downgraded quality to low because of study risks of bias and different participant indications. We found no differences in oxygenation variables: partial pressure of arterial oxygen (PaO₂)/fraction of inspired oxygen (FiO₂) (MD, IV, random-effects 7.31, 95% CI -23.69 to 41.31; four studies; 510 participants); PaO₂ (MD, IV, random-effects 2.79, 95% CI -5.47 to 11.05; three studies; 355 participants); and oxygen saturation (SpO₂) up to 24 hours (MD, IV, random-effects 0.72, 95% CI -0.73 to 2.17; four studies; 512 participants). Data from two studies showed that oxygen saturation measured after 24 hours was improved among those treated with HFNC (MD, IV, random-effects 1.28, 95% CI 0.02 to 2.55; 445 participants), but this difference was small and was not clinically significant. Along with concern about risks of bias and differences in participant indications, review authors noted a high level of unexplained statistical heterogeneity in oxygenation effect estimates, and we downgraded the quality of evidence to very low. Meta-analysis of three comparable studies showed no differences in carbon dioxide clearance among those treated with HFNC (MD, IV, random-effects -0.75, 95% CI -2.04 to 0.55; three studies; 590 participants). Two studies reported no differences in atelectasis; we did not combine these findings. Data from six studies (867 participants) comparing HFNC versus low-flow oxygen showed no differences in respiratory rates up to 24 hours according to type of oxygen delivery device (MD, IV, random-effects -1.51, 95% CI -3.36 to 0.35), and no difference after 24 hours (MD, IV, random-effects -2.71, 95% CI -7.12 to 1.70; two studies; 445 participants). Improvement in respiratory rates when HFNC was compared with CPAP or BiPAP was not clinically important (MD, IV, random-effects -0.89, 95% CI -1.74 to -0.05; two studies; 834 participants). Results showed no differences in patient-reported measures of comfort according to oxygen delivery devices in the short term (MD, IV, random-effects 0.14, 95% CI -0.65 to 0.93; three studies; 462 participants) and in the long term (MD, IV, random-effects -0.36, 95% CI -3.70 to 2.98; two studies; 445 participants); we downgraded the certainty of this evidence to low. Six studies measured dyspnoea on incomparable scales, yielding inconsistent study data. No study in this review provided data on positive end-expiratory pressure measured at the pharyngeal level, work of breathing, or cost comparisons of treatment.

AUTHORS' CONCLUSIONS

We were unable to demonstrate whether HFNC was a more effective or safe oxygen delivery device compared with other oxygenation devices in adult ICU patients. Meta-analysis could be performed for few studies for each outcome, and data for comparisons with CPAP or BiPAP were very limited. In addition, we identified some risks of bias among included studies, differences in patient groups, and high levels of statistical heterogeneity for some outcomes, leading to uncertainty regarding the results of our analysis. Consequently, evidence is insufficient to show whether HFNC provides safe and efficacious respiratory support for adult ICU patients.

Effect of High-Flow Nasal Cannula Oxygen Therapy Versus Conventional Oxygen Therapy and Noninvasive Ventilation on Reintubation Rate in Adult Patients After Extubation: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

PURPOSE

We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the effect of high-flow nasal cannula (HFNC) on reintubation in adult patients.

PROCEDURES

Ovid Medline, Embase, and Cochrane Database of Systematic Reviews were searched up to November 1, 2016, for RCTs comparing HFNC versus conventional oxygen therapy (COT) or noninvasive ventilation (NIV) in adult patients after extubation. The primary outcome was reintubation rate, and the secondary outcomes included complications, tolerance and comfort, time to reintubation, length of stay, and mortality. Dichotomous outcomes were presented as risk ratio (RR) with 95% confidence intervals (CIs) and continuous outcomes as weighted mean difference and 95% CIs. The random effects model was used for data pooling.

FINDINGS

Seven RCTs involving 2781 patients were included in the analysis. The HFNC had a similar reintubation rate compared to either COT (RR, 0.58; 95% CI, 0.21-1.60; P = .29; 5 RCTs, n = 1347) or NIV (RR, 1.11; 95% CI, 0.88-1.40; P = .37; 2 RCTs, n = 1434). In subgroup of critically ill patients, the HFNC group had a significantly lower reintubation rate compared to the COT group (RR, 0.35; 95% CI, 0.19-0.64; P = .0007; 2 RCTs, n = 632; interaction P = .07 compared to postoperative subgroup). Qualitative analysis suggested that HFNC might be associated with less complications and improved patient's tolerance and comfort. The HFNC might not delay reintubation. Trial sequential analysis on the primary outcome showed that required information size was not reached.

CONCLUSION

The evidence suggests that COT may still be the first-line therapy in postoperative patients without acute respiratory failure. However, in critically ill patients, HFNC may be a potential alternative respiratory support to COT and NIV, with the latter often associating with patient intolerance and requiring a monitored setting. Because required information size was not reached, further high-quality studies are required to confirm these results.

High-flow nasal cannula support therapy: new insights and improving performance

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2017. Other selected articles can be found online at http://ccforum.com/series/annualupdate2017 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901 .