Physiological effects of titrated oxygen via nasal high-flow cannulae in COPD exacerbations: A randomized controlled cross-over trial

[High-flow nasal oxygen therapy and hypercapnic acute respiratory failure]

Humidified high-flow nasal oxygen therapy (HFNO) has, in recent years, come to assume a key role in the management of hypoxemic acute respiratory failure (ARF). While non-invasive ventilation (NIV) currently represents the first-line ventilatory strategy in patients exhibiting hypercapnic ARF, the operating principles and physiological effects of HFNO could be interesting and useful in the initial management of hypercapnic ARF and/or after extubation, particularly in acute exacerbations of chronic obstructive pulmonary disease. Under these conditions, HFNO could be used either alone continuously or in combination with NIV during breaks in spontaneous breathing, depending on the severity and etiology of the underlying hypercapnic ARF.

Noninvasive respiratory support in the emergency department: Controversies and state-of-the-art recommendations

Acute respiratory failure is a common reason for emergency department visits and hospital admissions. Diverse underlying physiologic abnormalities lead to unique aspects about the most common causes of acute respiratory failure: acute decompensated heart failure, acute exacerbation of chronic obstructive pulmonary disease, and acute de novo hypoxemic respiratory failure. Noninvasive respiratory support strategies are increasingly used methods to support work of breathing and improve gas exchange abnormalities to improve outcomes relative to conventional oxygen therapy or invasive mechanical ventilation. Noninvasive respiratory support includes noninvasive positive pressure ventilation and nasal high flow, each with unique physiologic mechanisms. This paper will review the physiology of respiratory failure and noninvasive respiratory support modalities and offer data and guideline-driven recommendations in the context of key clinical controversies.

Respiratory support in the emergency department a systematic review and meta-analysis

BACKGROUND

An estimated 20% of emergency department (ED) patients require respiratory support (RS). Evidence suggests that nasal high flow (NHF) reduces RS need.

AIMS

This review compared NHF to conventional oxygen therapy (COT) or noninvasive ventilation (NIV) in adult ED patients.

METHOD

The systematic review (SR) and meta-analysis (MA) methods reflect the Cochrane Collaboration methodology. Six databases were searched for randomized controlled trials (RCTs) comparing NHF to COT or NIV use in the ED. Three summary estimates were reported: (1) need to escalate care, (2) mortality, and (3) adverse events (AEs).

RESULTS

This SR and MA included 18 RCTs (n = 1874 participants). Two of the five MA conclusions were statistically significant. Compared with COT, NHF reduced the risk of escalation by 45% (RR 0.55; 95% CI [0.33, 0.92], p = .02, NNT = 32); however, no statistically significant differences in risk of mortality (RR 1.02; 95% CI [0.68, 1.54]; p = .91) and AE (RR 0.98; 95% CI [0.61, 1.59]; p = .94) outcomes were found. Compared with NIV, NHF increased the risk of escalation by 60% (RR 1.60; 95% CI [1.10, 2.33]; p = .01); mortality risk was not statistically significant (RR 1.23, 95% CI [0.78, 1.95]; p = .37).

LINKING EVIDENCE TO ACTION

Evidence-based decision-making regarding RS in the ED is challenging. ED clinicians have at times had to rely on non-ED evidence to support their practice. Compared with COT, NHF was seen to be superior and reduced the risk of escalation. Conversely, for this same outcome, NIV was superior to NHF. However, substantial clinical heterogeneity was seen in the NIV delivered. Research considering NHF versus NIV is needed. COVID-19 has exposed the research gaps and slowed the progress of ED research.

High-flow nasal cannula may prolong the length of hospital stay in patients with hypercapnic acute COPD exacerbation

BACKGROUND

High-flow nasal cannula (HFNC) is increasingly used in patients with acute exacerbation of COPD (AECOPD). We aimed to confirm whether the baseline bicarbonate is an independent predictor of outcomes in patients with hypercapnic AECOPD receiving HFNC.

METHODS

This was a secondary analysis of a multicentre randomised trial that enrolled 330 patients with non-acidotic hypercapnic AECOPD supported by HFNC or conventional oxygen treatment (COT). We compared the length of stay (LOS) in hospital and the rate of non-invasive positive pressure ventilation (NPPV) use according to baseline bicarbonate levels using the log-rank test or Cox proportional hazard model.

RESULTS

In the high bicarbonate subgroup (n = 165, bicarbonate 35.0[33.3-37.9] mmol/L, partial pressure of arterial carbon dioxide [PaCO2] 56.8[52.0-62.8] mmHg), patients supported by HFNC had a remarkably prolonged LOS in hospital when compared to COT (HR 1.59[1.16-2.17], p = 0.004), whereas patients in the low bicarbonate subgroup (n = 165, bicarbonate 28.8[27.0-30.4] mmol/L, PaCO2 48.0[46.0-50.0] mmHg) had a comparable LOS in hospital regardless of respiratory support modalities. The rate of NPPV use in patients with high baseline bicarbonate level was significantly higher than that in patients with low baseline bicarbonate level (19.4 % vs. 3.0 %, p < 0.0001). Patients with high bicarbonate level in HFNC group had a lower rate of NPPV use compared to COT group (15.4 % vs. 23.0 %, p = 0.217).

CONCLUSIONS

Among patients with non-acidotic hypercapnic AECOPD with high baseline bicarbonate level, HFNC is significantly associated with a prolonged LOS in hospital, which may be due to the reduced escalation of NPPV treatment.

TRIAL REGISTRATION

clinicaltrials.gov (NCT03003559).

Effect of modified high-flow oxygen therapy on positive end-expiratory pressure and end-expiratory lung volume based on simulated lung platform

Objective

The aim of this study was to assess the effect of modified high-flow oxygen therapy on end-expiratory lung volume (EELV) and positive end-expiratory pressure (PEEP) in tracheotomized patients with normal pulmonary, acute hypoxic respiratory failure (AHRF) or chronic obstructive pulmonary disease (COPD).

Methods

A ventilator and an artificial lung model were used to simulate the normal or strong inspiratory effort state of normal lung, AHRF and COPD patients. The traditional high-flow respiratory humidification therapy device connected with a standard interface (group A), and the modified therapy device added two types of resistance valves (group B, inner diameter 7.7 mm, length 24.0 mm; group C, inner diameter 7.7 mm, length 34.0 mm) to the exhalation end of the standard interface. The changes of end-expiratory lung volume (ΔEELV) and PEEP with the increase of flow rate (10 L/min, 20 L/min, 30 L/min, 40 L/min, 50 L/min, 60 L/min) in the three groups was recorded.

Results

Under simulated conditions of normal lung, AHRF and COPD, as the flow rate increased by using the modified therapy device, the PEEP values in all groups showed an exponential increasing trend, and the ΔEELV also increased accordingly. In addition, under the same flow rate level, the PEEP values of the two modified high-flow oxygen therapies (Group B and Group C) were significantly higher than those of the standard high-flow oxygen therapy (Group A) (p < 0.05). In the normal lung model with normal or strong inspiratory effort, and in the AHRF or COPD model with strong inspiratory effort, when the flow rate was higher than 30 L/min, the PEEP levels of Group B were significantly lower than those of Group C (p < 0.05). In the AHRF model with normal inspiratory effort, when the flow rate was between 10 L/min and 60 L/min, the PEEP levels of Group B were significantly lower than those of Group C (p < 0.05). Moreover, in the COPD model with normal inspiratory effort, the PEEP levels of Group B were significantly lower than that of Group C only when the flow rate was 60 L/min (p < 0.05).

Conclusion

The addition of different types of resistance valves to the high-flow exhalation end may be a feasible solution to improve the clinical efficacy of tracheotomized high-flow oxygen therapy.

Effect of high-flow nasal cannula versus non-invasive ventilation in preventing re-intubation in high-risk chronic obstructive pulmonary disease patients: A randomised controlled trial

Background

Currently, a high-flow nasal cannula (HFNC) has been shown to improve extubation outcomes. However, there is a lack of evidence on the utilisation of HFNC in high-risk chronic obstructive pulmonary disease (COPD) patients. This study aimed to compare the effectiveness of HFNC versus non-invasive ventilation (NIV) in preventing re-intubation following planned extubation in high-risk COPD patients.

Patients and Methods

In this prospective, randomised, controlled trial, 230 mechanically ventilated COPD patients at high risk for re-intubation who fulfilled the criteria for planned extubation were enrolled. Post-extubation blood gases and vital signs at 1, 24, and 48 hours were recorded. The primary outcome was the re-intubation rate within 72 hours. Secondary outcomes included post-extubation respiratory failure, respiratory infection, intensive care unit and hospital length of stay, and mortality rate at 60 days.

Results

230 patients after planned extubation were randomly allocated to receive either HFNC (n = 120) or NIV (n = 110). Re-intubation within 72 hours was significantly lower in the high-flow group: 8 patients (6.6%) versus 23 patients (20.9%) in the NIV group {absolute difference, 14.3% [95% confidence interval (CI), 10.9-16.3]; P = 0.001}. The frequency of post-extubation respiratory failure was less in patients assigned to HFNC than in those allocated NIV (25% vs. 35.4%) [absolute difference, 10.4% (95% CI, 2.4-14.3); P = 0.001]. There was no significant difference between the two groups regarding reasons for respiratory failure after extubation. It was observed that the 60-day mortality rate was lower in patients who received HFNC than in those assigned to NIV (5% vs. 13.6%) [absolute difference, 8.6 (95% CI, 4.3 to 9.10); P = 0.001].

Conclusion

The use of HFNC after extubation appears to be superior to NIV in reducing the risk of re-intubation within 72 hours and 60-day mortality in high-risk COPD patients.

International Survey of High-Flow Nasal Therapy Use for Respiratory Failure in Adult Patients

(1) Background: High-flow nasal therapy (HFNT) has shown several benefits in addressing respiratory failure. However, the quality of evidence and the guidance for safe practice are lacking. This survey aimed to understand HFNT practice and the needs of the clinical community to support safe practice. (2) Method: A survey questionnaire was developed and distributed to relevant healthcare professionals through national networks in the UK, USA and Canada; responses were collected between October 2020 and April 2021. (3) Results: In the UK and Canada, HFNT was used in 95% of hospitals, with the highest use being in the emergency department. HNFT was widely used outside of a critical care setting. HFNT was mostly used to treat acute type 1 respiratory failure (98%), followed by acute type 2 respiratory failure and chronic respiratory failure. Guideline development was felt to be important (96%) and urgent (81%). Auditing of practice was lacking in 71% of hospitals. In the USA, HFNT was broadly similar to UK and Canadian practice. (4) Conclusions: The survey results reveal several key points: (a) HFNT is used in clinical conditions with limited evidence; (b) there is a lack of auditing; (c) it is used in wards that may not have the appropriate skill mix; and (d) there is a lack of guidance for HFNT use.

High-Flow Nasal Cannula versus Noninvasive Ventilation in AECOPD Patients with Respiratory Acidosis: A Retrospective Propensity Score-Matched Study

Background

Limited data are available about the clinical outcomes of AECOPD patients with respiratory acidosis treated with HFNC versus NIV.

Methods

We conducted a retrospective study to compare the efficacy of HFNC with NIV as initial ventilation support strategy in AECOPD patients with respiratory acidosis. Propensity score matching (PSM) was implemented to increase between-group comparability. Kaplan-Meier analysis was utilized to evaluate differences between the HFNC success, HFNC failure, and NIV groups. Univariate analysis was performed to identify the features that differed significantly between the HFNC success and HFNC failure groups.

Results

After screening 2219 hospitalization records, 44 patients from the HFNC group and 44 from the NIV group were successfully matched after PSM. The 30-day mortality (4.5% versus 6.8%, p = 0.645) and 90-day mortality (4.5% versus 11.4%, p = 0.237) did not differ between the HFNC and NIV groups. Length of ICU stay (median: 11 versus 18 days, p = 0.001), length of hospital stay (median: 14 versus 20 days, p = 0.001), and hospital cost (median: 4392 versus 8403 $USD, p = 0.001) were significantly lower in the HFNC group compared with NIV group. The treatment failure rate was much higher in the HFNC group than in the NIV group (38.6% versus 11.4%, p = 0.003). However, patients who experienced HFNC failure and switched to NIV showed similar clinical outcomes to those who first received NIV. Univariate analysis showed that log NT-proBNP was an important factor for HFNC failure (p = 0.007).

Conclusions

Compared with NIV, HFNC followed by NIV as rescue therapy may be a viable initial ventilation support strategy for AECOPD patients with respiratory acidosis. NT-proBNP may be an important factor for HFNC failure in these patients. Further well-designed randomized controlled trials are needed for more accurate and reliable results.

Cost-Effectiveness of Humidified High-Flow Therapy (HHFT) for COPD Patients on Long-Term Oxygen Therapy

Purpose

Chronic obstructive pulmonary disease (COPD) is the third leading cause of mortality, and is associated with significant respiratory impairment, decreased quality of life, and high health care costs. Recent evidence indicates significant clinical benefit results from adding humidified high-flow therapy (HHFT) to standard long-term oxygen therapy (LTOT) as a home-based therapy in persons with severe COPD. The objective was to evaluate the cost-effectiveness of adding HHFT to standard treatment of COPD patients using LTOT with US healthcare cost estimates.

Patients and Methods

A Markov state-transition model was developed using data from a prospective clinical trial of adding HHFT to standard therapy for persons with severe COPD using LTOT. The analysis was conducted from the US health care system perspective using a 5-year time horizon and 3% discount rate. QALYs and downstream healthcare costs were modeled. One-way and probabilistic sensitivity analyses were used to examine the impact of input parameters on the incremental net monetary benefit (NMB).

Results

Incremental QALYs accrued were 0.058 (2.047 vs 1.989 QALYs for HHFT and standard therapy groups respectively). Incremental total costs were -$3939 ($47,516 vs $51,455 for HHFT and standard therapy groups respectively). Thus, HHFT was the dominant treatment in the analysis, resulting on both better health and lower total costs. Varying utility and cost inputs individually never resulted in NMB approaching 0. Probabilistic analyses indicate that HHFT is cost-effective in 84% of simulations.

Conclusion

Our results indicate that the reductions in acute exacerbations of COPD (AECOPDs) that result from adding HHFT for persons with COPD on LTOT will produce both health benefit (QALYs) and cost savings. Cost savings occur because the HHFT device costs are more than offset by reductions in costly COPD exacerbations. Health care systems and payors can benefit from wider implementation of HHFT with existing treatments.

The use of high-flow nasal cannula in patients with chronic obstructive pulmonary disease under exacerbation and stable phases: A systematic review and meta-analysis

BACKGROUND

High-flow nasal cannula (HFNC) has been increasingly utilized in patients with chronic obstructive pulmonary disease (COPD); however, the effects on reducing the need for intubation or reintubation remain unclear.

OBJECTIVES

We aimed to investigate whether HFNC therapy was superior to conventional oxygen therapy (COT) or noninvasive ventilation (NIV) in patients with COPD.

METHODS

A literature search was performed in electronic databases until October 1st, 2022. The primary outcome was the need for intubation/reintubation. All analyses were performed using R (version 4.0.3) and STATA SE (version 15.1).

RESULTS

When HFNC therapy was compared with NIV in patients with COPD under initial respiratory support and postextubation, no significant differences were found in the risk of intubation (RR 0.84, 95% CI 0.36 to 1.98) and reintubation (RR 1.35, 95% CI 0.73 to 2.50). Compared to NIV, HFNC therapy did not decrease the partial pressure of carbon dioxide or increase the partial pressure of oxygen to the fraction of inspired oxygen. However, HFNC therapy was associated with a lower incidence of skin breakdown (RR 0.52, 95% CI 0.39 to 0.69) and a higher comfort score (SMD 0.90, 95% CI 0.60 to 1.20) than NIV. When HFNC therapy was compared with COT during initial respiratory treatment for COPD exacerbation, a lower risk of treatment failure was found (RR 0.58, 95% CI 0.37 to 0.89). When HFNC therapy was compared with long-term oxygen therapy, quality of life (measured by SGRQ-C) was significantly improved (SMD -0.42, 95% CI -0.69 to -0.14).

CONCLUSION

HFNC therapy might be used as an alternative to NIV for COPD exacerbation with mild-moderate hypercapnia under close monitoring and is a potential domiciliary treatment for stable COPD.

Comparison of high-flow nasal cannula and conventional oxygen therapy for high-risk patients during bronchoscopy examination: protocol for a randomized controlled trial

INTRODUCTION

High-flow nasal cannula (HFNC) has been proven to improve oxygenation and avoid intubation in hypoxemic patients. It has also been utilized during endoscopy examination to reduce the incidence of hypoxia. However, little is known about the effects of HFNC versus conventional oxygen therapy (COT) on oxygenation during bronchoscopy examination via nasal route; particularly, no study has compared the use of HFNC with that of COT at similar F_IO₂ for patients who have high-risk factors of desaturation during bronchoscopy examination.

METHODS AND ANALYSIS

This randomized controlled trial will be implemented in four academic centers in China. Patients who have high-risk factors including hypoxemia, hypercapnia, morbid obesity, and narrow airway will be enrolled to use HFNC or COT during bronchoscopy examination. In the HFNC group, the initial gas flow will be set at 50 L/min with a fraction of inspired oxygen (F_IO₂) at 0.45, if the patient tolerates, the flow can be increased to 60L/min at most, while in the COT group, oxygen flow will be set at 6 L/min via a conventional nasal cannula. After 5 min pre-oxygenation, the bronchoscope will be inserted via the nasal route. Vital signs, oxygenation (SpO₂), and transcutaneous CO₂ (PtCO₂) will be continuously monitored. The primary outcome is the incidence of hypoxemia, defined as SpO₂ < 90% for 10 s during bronchoscopy examination, and secondary outcomes include the need for treatment escalation and adverse events.

DISCUSSION

Hypoxia is a common complication of bronchoscopy, our study attempted to demonstrate that HFNC may reduce the probability of hypoxia during bronchoscopy in high-risk patients. The results will be disseminated through peer-reviewed journals and national and international conferences.

TRIAL REGISTRATION

http://www.chictr.org.cn/ : ChiCTR2100055038. Registered on 31 December 2021.

High-flow nasal cannula therapy with sequential noninvasive ventilation versus noninvasive ventilation alone as the initial ventilatory strategy in acute COPD exacerbations: study protocol for a randomized controlled trial

BACKGROUND

Noninvasive ventilation (NIV) is the recommended mode of ventilation used in acute respiratory failure secondary to an acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Recent data has shown that high-flow nasal cannula (HFNC) treatment can be an alternative for patients with hypercapnic respiratory failure. The purpose of this study is to evaluate HFNC with sequential NIV versus NIV alone as the initial ventilatory strategy in AECOPD.

METHODS

This investigator-initiated, unblinded, single center, randomized controlled trial will be conducted in the emergency department, emergency intensive care unit, or respiratory intensive care unit of a tertiary-care urban teaching hospital. A total of 66 patients will be enrolled and randomized into the intervention group (HFNC with sequential NIV) or the control group (NIV group). The primary endpoint will be the mean difference in PaCO₂ from baseline to 24 h after randomization. Secondary endpoints include the mean difference in PaCO₂ from baseline to 6, 12, and 18 h, as well as the dyspnea score, overall discomfort score, rate of treatment failure, respiratory rate, rate of endotracheal intubation, length of hospital stay, and mortality.

DISCUSSION

Taking the advantages of both HFNC and NIV on AECOPD patients into account, we designed this clinical trial to investigate the combination of these ventilatory strategies. This trial will help us understand how HFNC with sequential NIV compares to NIV alone in treating AECOPD patients.

TRIAL REGISTRATION

ChiCTR2100054809.

Comparison of Conventional Oxygen Therapy With High-Flow Nasal Oxygenation in the Management of Hypercapnic Respiratory Failure

Introduction: The effectiveness of high-flow nasal oxygenation (HFNO) in patients with hypercapnic respiratory failure (RF) remains controversial. The current study compared the effectiveness of HFNO in patients with hypercapnic RF with conventional oxygen therapy (COT).

Objectives: The primary objective was to compare changes in the partial pressure of carbon dioxide (PaCO2) between those receiving COT and HFNO. The secondary objectives were to compare changes in the partial pressure of oxygen (PaO2), oxygen saturation (SpO2), respiratory rate (RR), serum bicarbonate level, base excess, lactate level, and incidence of the need for non-invasive ventilation (NIV) and mechanical ventilation (MV).

Methods: We recruited 30 patients with mild to moderate hypercapnic RF in the HFNO group, and data of 30 patients from historical controls, who matched the inclusion criteria, were obtained from medical records for comparison (COT group). The study was terminated after two hours, and patients were managed per the existing protocol after that. Arterial blood gas (ABG) analysis was repeated at the baseline, first, second, and third hours.

Results: In the COT group, the mean RR at the baseline, first, second, and third hours was 24.5 ± 2.61, 24.9 ± 3.03, 26.03 ± 3.4, and 22.90 ± 1.86, whereas, in the HFNO group, it was 25.93 ± 3.91, 23.00 ± 3.54, 22.50 ± 3.38, and 21.90 ± 3.57, respectively. The mean PaCO2 in the COT vs. HFNO groups was 54.45 ± 5.83 vs. 62.22 ± 9.15, 57.74 ± 6.05 vs. 58.65 ± 10.43, 60.79 ± 7.48 vs. 60.41 ± 11.24, and 55.23 ± 6.63 vs. 56.95 ± 10.31. The mean SpO2 in the COT group at these points of time was 94.50 ± 1.46, 95.4 ± 1.28, 96.10 ± 1.84, and 97.53 ± 2.05, whereas, in the HFNO group, it was 95.40 ± 2.55, 98.63 ± 1.43, 99.00 ± 1.66, and 99.50 ± 1.31, respectively. The patients who needed NIV after the study period were 50% and 36.67% in the COT and HFNO groups, respectively.

Conclusions: There was no change in PaCO2 levels with HFNO, but there was a significant improvement in SpO2 and PaO2 levels and a decreased RR. Following the termination of the study protocol, more patients in the COT group needed NIV than those in the HFNO group.

Prediction of high-flow nasal cannula outcomes at the early phase using the modified respiratory rate oxygenation index

BACKGROUND

This study was designed to explore the early predictive value of the respiratory rate oxygenation (ROX) index modified by PaO₂ (mROX) in high-flow nasal cannula (HFNC) therapy in patients with acute hypoxemia respiratory failure (AHRF).

METHOD

Seventy-five patients with AHRF treated with HFNC were retrospectively reviewed. Respiratory parameters at baseline and 2 h after HFNC initiation were analyzed. The predictive value of the ROX (ratio of pulse oximetry/FIO₂ to respiratory rate) and mROX (ratio of arterial oxygen /FIO₂ to respiratory rate) indices with two variations by adding heart rate to each index (ROX-HR and mROX-HR) was evaluated.

RESULTS

HFNC therapy failed in 24 patients, who had significantly higher intensive care unit (ICU) mortality and longer ICU stay. Both the ROX and mROX indices at 2 h after HFNC initiation can predict the risk of intubation after HFNC. Two hours after HFNC initiation, the mROX index had a higher area under the receiver operating characteristic curve (AUROC) for predicting HFNC success than the ROX index. Besides, baseline mROX index of greater than 7.1 showed a specificity of 100% for HFNC success.

CONCLUSION

The mROX index may be a suitable predictor of HFNC therapy outcomes at the early phase in patients with AHRF.

High-flow nasal cannula versus conventional oxygen therapy in acute COPD exacerbation with mild hypercapnia: a multicenter randomized controlled trial

Background

High-flow nasal cannula (HFNC) can improve ventilatory function in patients with acute COPD exacerbation. However, its effect on clinical outcomes remains uncertain.

Methods

This randomized controlled trial was conducted from July 2017 to December 2020 in 16 tertiary hospitals in China. Patients with acute COPD exacerbation with mild hypercapnia (pH ≥ 7.35 and arterial partial pressure of carbon dioxide > 45 mmHg) were randomly assigned to either HFNC or conventional oxygen therapy. The primary outcome was the proportion of patients who met the criteria for intubation during hospitalization. Secondary outcomes included treatment failure (intolerance and need for non-invasive or invasive ventilation), length of hospital stay, hospital cost, mortality, and readmission at day 90.

Results

Among 337 randomized patients (median age, 70.0 years; 280 men [83.1%]; median pH 7.399; arterial partial pressure of carbon dioxide 51 mmHg), 330 completed the trial. 4/158 patients on HFNC and 1/172 patient on conventional oxygen therapy met the criteria for intubation (P = 0.198). Patients progressed to NPPV in both groups were comparable (15 [9.5%] in the HFNC group vs. 22 [12.8%] in the conventional oxygen therapy group; P = 0.343). Compared with conventional oxygen therapy, HFNC yielded a significantly longer median length of hospital stay (9.0 [interquartile range, 7.0–13.0] vs. 8.0 [interquartile range, 7.0–11.0] days) and a higher median hospital cost (approximately $2298 [interquartile range, $1613–$3782] vs. $2005 [interquartile range, $1439–$2968]). There were no significant differences in other secondary outcomes between groups.

Conclusions

In this multi-center randomized controlled study, HFNC compared to conventional oxygen therapy did not reduce need for intubation among acute COPD exacerbation patients with mild hypercapnia. The future studies should focus on patients with acute COPD exacerbation with respiratory acidosis (pH < 7.35). However, because the primary outcome rate was well below expected, the study was underpowered to show a meaningful difference between the two treatment groups.

Trial registration: NCT03003559. Registered on December 28, 2016.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-03973-7.

Noninvasive Oxygenation in Patients with Acute Respiratory Failure: Current Perspectives

Purpose of Review

High-flow nasal oxygen and noninvasive ventilation are two alternative strategies to standard oxygen in the management of acute respiratory failure.

Discussion

Although high-flow nasal oxygen has gained major popularity in ICUs due to its simplicity of application, good comfort for patients, efficiency in improving oxygenation and promising results in patients with acute hypoxemic respiratory failure, further large clinical trials are needed to confirm its superiority over standard oxygen. Non-invasive ventilation may have deleterious effects, especially in patients exerting strong inspiratory efforts, and no current recommendations support its use in this setting. Protective non-invasive ventilation using higher levels of positive-end expiratory pressure, more prolonged sessions and other interfaces such as the helmet may have beneficial physiological effects leading to it being proposed as alternative to high-flow nasal oxygen in acute hypoxemic respiratory failure. By contrast, non-invasive ventilation is the first-line strategy of oxygenation in patients with acute exacerbation of chronic lung disease, while high-flow nasal oxygen could be an alternative to non-invasive ventilation after partial reversal of respiratory acidosis. Questions remain about the target populations and non-invasive oxygen strategy representing the best alternative to standard oxygen in acute hypoxemic respiratory failure. As concerns acute on-chronic-respiratory failure, the place of high-flow nasal oxygen remains to be evaluated.

Current Practice of High Flow through Nasal Cannula in Exacerbated COPD Patients

Acute Exacerbation of Chronic Obstructive Pulmonary Disease is a form of severe Acute Respiratory Failure (ARF) requiring Conventional Oxygen Therapy (COT) in the case of absence of acidosis or the application of Non-Invasive Ventilation (NIV) in case of respiratory acidosis. In the last decade, High Flow through Nasal Cannula (HFNC) has been increasingly used, mainly in patients with hypoxemic ARF. However, some studies were also published in AECOPD patients, and some evidence emerged. In this review, after describing the mechanism underlying potential clinical benefits, we analyzed the possible clinical application of HFNC to AECOPD patients. In the case of respiratory acidosis, the gold-standard treatment remains NIV, supported by strong evidence in favor. However, HFNC may be considered as an alternative to NIV if the latter fails for intolerance. HFNC should also be considered and preferred to COT at NIV breaks and weaning. Finally, HFNC should also be preferred to COT as first-line oxygen treatment in AECOPD patients without respiratory acidosis.

[Translated article] Spanish COPD Guidelines (GesEPOC) 2021 Update. Diagnosis and Treatment of COPD Exacerbation Syndrome

This article details the GesEPOC 2021 recommendations on the diagnosis and treatment of COPD exacerbation syndrome (CES). The guidelines propose a definition-based syndromic approach, a new classification of severity, and the recognition of different treatable traits (TT), representing a new step toward personalized medicine. The evidence is evaluated using GRADE methodology, with the incorporation of 6 new PICO questions. The diagnostic process comprises four stages: 1) establish a diagnosis of CES, 2) assess the severity of the episode, 3) identify the trigger, and 4) address TTs. This diagnostic process differentiates an outpatient approach, that recommends the inclusion of a basic battery of tests, from a more comprehensive hospital approach, that includes the study of different biomarkers and imaging tests. Bronchodilator treatment for immediate relief of symptoms is considered essential for all patients, while the use of antibiotics, systemic corticosteroids, oxygen therapy, and assisted ventilation and the treatment of comorbidities will vary depending on severity and possible TTs. The use of antibiotics will be indicated particularly if sputum color changes, when ventilatory assistance is required, in cases involving pneumonia, and in patients with elevated C-reactive protein (≥ 20 mg/L). Systemic corticosteroids are recommended in CES that requires admission and are suggested in moderate CES. These drugs are more effective in patients with blood eosinophil counts ≥ 300 cells/mm3. Acute-phase non-invasive mechanical ventilation is specified primarily for patients with CES who develop respiratory acidosis despite initial treatment.

Expanding the utility of the ROX index among patients with acute hypoxemic respiratory failure

BACKGROUND

Delaying intubation in patients who fail high-flow nasal cannula (HFNC) may result in increased mortality. The ROX index has been validated to predict HFNC failure among pneumonia patients with acute hypoxemic respiratory failure (AHRF), but little information is available for non-pneumonia causes. In this study, we validate the ROX index among AHRF patients due to both pneumonia or non-pneumonia causes, focusing on early prediction.

METHODS

This was a retrospective observational study in eight Singapore intensive care units from 1 January 2015 to 30 September 2017. All patients >18 years who were treated with HFNC for AHRF were eligible and recruited. Clinical parameters and arterial blood gas values at HFNC initiation and one hour were recorded. HFNC failure was defined as requiring intubation post-HFNC initiation.

RESULTS

HFNC was used in 483 patients with 185 (38.3%) failing HFNC. Among pneumonia patients, the ROX index was most discriminatory in pneumonia patients one hour after HFNC initiation [AUC 0.71 (95% CI 0.64-0.79)], with a threshold value of <6.06 at one hour predicting HFNC failure (sensitivity 51%, specificity 80%, positive predictive value 61%, negative predictive value 73%). The discriminatory power remained moderate among pneumonia patients upon HFNC initiation [AUC 0.65 (95% CI 0.57-0.72)], non-pneumonia patients at HFNC initiation [AUC 0.62 (95% CI 0.55-0.69)] and one hour later [AUC 0.63 (95% CI 0.56-0.70)].

CONCLUSION

The ROX index demonstrated moderate discriminatory power among patients with either pneumonia or non-pneumonia-related AHRF at HFNC initiation and one hour later.

High Flow Nasal Cannula Therapy in the Emergency Department: Main Benefits in Adults, Pediatric Population and against COVID-19: A Narrative Review

This review aims to summarize the literature’s main results about high flow nasal cannula therapy (HFNC) HFNC benefits in the Emergency Department (ED) in adults and pediatrics, including new Coronavirus Disease (COVID-19). HFNC has recently been established as the usual treatment in the ED to provide oxygen support. Its use has been generalized due to its advantages over traditional oxygen therapy devices, including decreased nasopharyngeal resistance, washing out of the nasopharyngeal dead space, generation of positive pressure, increasing alveolar recruitment, easy adaptation due to the humidification of the airways, increased fraction of inspired oxygen and improved mucociliary clearance. A wide range of pathologies has been studied to evaluate the potential benefits of HFNC; some examples are heart failure, pneumonia, chronic pulmonary obstructive disease, asthma, and bronchiolitis. The regular use of this oxygen treatment is not established yet due to the literature’s controversial results. However, several authors suggest that it could be useful in several pathologies that generate acute respiratory failure. Consequently, the COVID-19 irruption has generated the question of HFNC as a safety and effective treatment. Our results suggested that HFNC seems to be a useful tool in the ED, especially in patients affected by acute hypoxemic respiratory failure, acute heart failure, pneumonia, bronchiolitis, asthma and acute respiratory distress syndrome in patients affected by COVID-19. Its benefits in hypercapnic respiratory failure are more discussed, being only observed benefits in patients with mild-moderate disease. These results are based in clinical as well as cost-effectiveness outcomes. Future studies with largest populations are required to confirm these results as well as establish a practical guideline to use this device.

2021 Guideline for the Management of COPD Exacerbations: Emergency Medicine Association of Turkey (EMAT) / Turkish Thoracic Society (TTS) Clinical Practice Guideline Task Force

Chronic obstructive pulmonary disease (COPD) is an important public health problem that manifests with exacerbations and causes serious mortality and morbidity in both developed and developing countries. COPD exacerbations usually present to emergency departments, where these patients are diagnosed and treated. Therefore, the Emergency Medicine Association of Turkey and the Turkish Thoracic Society jointly wanted to implement a guideline that evaluates the management of COPD exacerbations according to the current literature and provides evidence-based recommendations. In the management of COPD exacerbations, we aim to support the decision-making process of clinicians dealing with these patients in the emergency setting.

High-flow nasal cannula therapy: A multicentred survey of the practices among physicians and respiratory therapists in Singapore

BACKGROUND

Use of high-flow nasal cannula (HFNC) has become a regular intervention in the intensive care units especially in patients coming in with hypoxaemic respiratory failure. Clinical practices may differ from published literature.

OBJECTIVES

The objective of this study was to determine the clinical practices of physicians and respiratory therapists (RTs) on the use of HFNC.

METHODS

A retrospective observational study looking at medical records on HFNC usage from January 2015 to September 2017 was performed and was followed by a series of questions related to HFNC practices. The survey involved physicians and RTs in intensive care units from multiple centres in Singapore from January to April 2018. Indications and thresholds for HFNC usage with titration and weaning practices were compared with the retrospective observational study data.

RESULTS

One hundred twenty-three recipients (69.9%) responded to the survey and reported postextubation (87.8%), pneumonia in nonimmunocompromised (65.9%), and pneumonia in immunocompromised (61.8%) patients as the top three indications for HFNC. Of all, 39.8% of respondents wanted to use HFNC for palliative intent. Similar practices were observed in the retrospective study with the large cohort of 63% patients (483 of the total 768 patients) where HFNC was used for acute hypoxaemic respiratory failure and 274 (35.7%) patients to facilitate extubation. The survey suggested that respondents would initiate HFNC at a lower fraction of inspired oxygen (FiO₂), higher partial pressure of oxygen to FiO₂ ratio, and higher oxygen saturation to FiO₂ ratio for nonpneumonia patients than patients with pneumonia. RTs were less likely to start HFNC for patients suffering from pneumonia and interstitial lung disease than physicians. RTs also preferred adjustment of FiO₂ to improve oxygen saturations and noninvasive ventilation for rescue.

CONCLUSIONS

Among the different intensive care units surveyed, the indications and thresholds for the initiation of HFNC differed in the clinical practices of physicians and RTs.

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).

Appropriate Use of High-Flow Nasal Oxygen in Hospitalized Patients for Initial or Postextubation Management of Acute Respiratory Failure: A Clinical Guideline From the American College of Physicians

DESCRIPTION

The American College of Physicians (ACP) developed this guideline to provide clinical recommendations on the appropriate use of high-flow nasal oxygen (HFNO) in hospitalized patients for initial or postextubation management of acute respiratory failure. It is based on the best available evidence on the benefits and harms of HFNO, taken in the context of costs and patient values and preferences.

METHODS

The ACP Clinical Guidelines Committee based these recommendations on a systematic review on the efficacy and safety of HFNO. The patient-centered health outcomes evaluated included all-cause mortality, hospital length of stay, 30-day hospital readmissions, hospital-acquired pneumonia, days of intubation or reintubation, intensive care unit (ICU) admission and ICU transfers, patient comfort, dyspnea, delirium, barotrauma, compromised nutrition, gastric dysfunction, functional independence at discharge, discharge disposition, and skin breakdown. This guideline was developed using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) method.

TARGET AUDIENCE AND PATIENT POPULATION

The target audience is all clinicians, and the target patient population is adult patients with acute respiratory failure treated in a hospital setting (including emergency departments, hospital wards, intermediate or step-down units, and ICUs).

RECOMMENDATION 1A

ACP suggests that clinicians use high-flow nasal oxygen rather than noninvasive ventilation in hospitalized adults for the management of acute hypoxemic respiratory failure (conditional recommendation; low-certainty evidence).

RECOMMENDATION 1B

ACP suggests that clinicians use high-flow nasal oxygen rather than conventional oxygen therapy for hospitalized adults with postextubation acute hypoxemic respiratory failure (conditional recommendation; low-certainty evidence).

High flow nasal oxygen for acute type two respiratory failure: a systematic review

Background: Acute type two respiratory failure (AT2RF) is characterized by high carbon dioxide levels (PaCO 2 >6kPa). Non-invasive ventilation (NIV), the current standard of care, has a high failure rate. High flow nasal therapy (HFNT) has potential additional benefits such as CO 2 clearance, the ability to communicate and comfort. The primary aim of this systematic review is to determine whether HFNT in AT2RF improves 1) PaCO 2, 2) clinical and patient-centred outcomes and 3) to assess potential harms. Methods: We searched EMBASE, MEDLINE and CENTRAL  (January 1999-January 2021). Randomised controlled trials (RCTs) and cohort studies comparing HFNT with low flow nasal oxygen (LFO) or NIV were included. Two authors independently assessed studies for eligibility, data extraction and risk of bias. We used Cochrane risk of bias tool for RCTs and Ottawa-Newcastle scale for cohort studies. Results: From 727 publications reviewed, four RCTs and one cohort study (n=425) were included. In three trials of HFNT vs NIV, comparing PaCO 2 (kPa) at last follow-up time point, there was a significant reduction at four hours (1 RCT; HFNT median 6.7, IQR 5.6 - 7.7 vs NIV median 7.6, IQR 6.3 - 9.3) and no significant difference at  24-hours or five days. Comparing HFNT with LFO, there was no significant difference at 30-minutes. There was no difference in intubation or mortality. Conclusions: This review identified a small number of studies with low to very low certainty of evidence. A reduction of PaCO 2 at an early time point of four hours post-intervention was demonstrated in one small RCT. Significant limitations of the included studies were lack of adequately powered outcomes and clinically relevant time-points and small sample size. Accordingly, systematic review cannot recommend the use of HFNT as the initial management strategy for AT2RF and trials adequately powered to detect clinical and patient-relevant outcomes are urgently warranted.

High flow nasal oxygen for acute type two respiratory failure: a systematic review

Background: Acute type two respiratory failure (AT2RF) is characterized by high carbon dioxide levels (PaCO 2 >6kPa). Non-invasive ventilation (NIV), the current standard of care, has a high failure rate. High flow nasal therapy (HFNT) has potential additional benefits such as CO 2 clearance, the ability to communicate and comfort. The primary aim of this systematic review is to determine whether HFNT in AT2RF improves 1) PaCO 2, 2) clinical and patient-centred outcomes and 3) to assess potential harms. Methods: We searched EMBASE, MEDLINE and CENTRAL  (January 1999-January 2021). Randomised controlled trials (RCTs) and cohort studies comparing HFNT with low flow nasal oxygen (LFO) or NIV were included. Two authors independently assessed studies for eligibility, data extraction and risk of bias. We used Cochrane risk of bias tool for RCTs and Ottawa-Newcastle scale for cohort studies. Results: From 727 publications reviewed, four RCTs and one cohort study (n=425) were included. In three trials of HFNT vs NIV, comparing PaCO 2 (kPa) at last follow-up time point, there was a significant reduction at four hours (1 RCT; HFNT median 6.7, IQR 5.6 - 7.7 vs NIV median 7.6, IQR 6.3 - 9.3) and no significant difference at  24-hours or five days. Comparing HFNT with LFO, there was no significant difference at 30-minutes. There was no difference in intubation or mortality. Conclusions: This review identified a small number of studies with low to very low certainty of evidence. A reduction of PaCO 2 at an early time point of four hours post-intervention was demonstrated in one small RCT. Significant limitations of the included studies were lack of adequately powered outcomes and clinically relevant time-points and small sample size. Accordingly, systematic review cannot recommend the use of HFNT as the initial management strategy for AT2RF and trials adequately powered to detect clinical and patient-relevant outcomes are urgently warranted.

Spanish COPD Guidelines (GesEPOC) 2021 Update Diagnosis and Treatment af COPD Exacerbation Syndrome

This article details the GesEPOC 2021 recommendations on the diagnosis and treatment of COPD exacerbation syndrome (CES). The guidelines propose a definition-based syndromic approach, a new classification of severity, and the recognition of different treatable traits (TT), representing a new step toward personalized medicine. The evidence is evaluated using GRADE methodology, with the incorporation of 6 new PICO questions. The diagnostic process comprises four stages: 1) establish a diagnosis of CES, 2) assess the severity of the episode, 3) identify the trigger, and 4) address TTs. This diagnostic process differentiates an outpatient approach, that recommends the inclusion of a basic battery of tests, from a more comprehensive hospital approach, that includes the study of different biomarkers and imaging tests. Bronchodilator treatment for immediate relief of symptoms is considered essential for all patients, while the use of antibiotics, systemic corticosteroids, oxygen therapy, and assisted ventilation and the treatment of comorbidities will vary depending on severity and possible TTs. The use of antibiotics will be indicated particularly if sputum color changes, when ventilatory assistance is required, in cases involving pneumonia, and in patients with elevated C-reactive protein (≥ 20 mg/L). Systemic corticosteroids are recommended in CES that requires admission and are suggested in moderate CES. These drugs are more effective in patients with blood eosinophil counts ≥ 300 cells/mm³. Acute-phase non-invasive mechanical ventilation is specified primarily for patients with CES who develop respiratory acidosis despite initial treatment.

Visually guided inspiration breath-hold facilitated with nasal high flow therapy in locally advanced lung cancer

BACKGROUND AND PURPOSE

Reducing breathing motion in radiotherapy (RT) is an attractive strategy to reduce margins and better spare normal tissues. The objective of this prospective study (NCT03729661) was to investigate the feasibility of irradiation of non-small cell lung cancer (NSCLC) with visually guided moderate deep inspiration breath-hold (IBH) using nasal high-flow therapy (NHFT).

MATERIAL AND METHODS

Locally advanced NSCLC patients undergoing photon RT were given NHFT with heated humidified air (flow: 40 L/min with 80% oxygen) through a nasal cannula. IBH was monitored by optical surface tracking (OST) with visual feedback. At a training session, patients had to hold their breath as long as possible, without and with NHFT. For the daily cone beam CT (CBCT) and RT treatment in IBH, patients were instructed to keep their BH as long as it felt comfortable. OST was used to analyze stability and reproducibility of the BH, and CBCT to analyze daily tumor position. Subjective tolerance was measured with a questionnaire at 3 time points.

RESULTS

Of 10 included patients, 9 were treated with RT. Seven (78%) completed the treatment with NHFT as planned. At the training session, the mean BH length without NHFT was 39 s (range 15-86 s), and with NHFT 78 s (range 29-223 s) (p = .005). NHFT prolonged the BH duration by a mean factor of 2.1 (range 1.1-3.9s). The mean overall stability and reproducibility were within 1 mm. Subjective tolerance was very good with the majority of patients having no or minor discomfort caused by the devices. The mean inter-fraction tumor position variability was 1.8 mm (-1.1-8.1 mm;SD 2.4 mm).

CONCLUSION

NHFT for RT treatment of NSCLC in BH is feasible, well tolerated and significantly increases the breath-hold duration. Visually guided BH with OST is stable and reproducible. We therefore consider this an attractive patient-friendly approach to treat lung cancer patients with RT in BH.

Acute Responses to Oxygen Delivery via High Flow Nasal Cannula in Patients with Severe Chronic Obstructive Pulmonary Disease-HFNC and Severe COPD

Differences in oxygen delivery methods to treat hypoxemia have the potential to worsen CO₂ retention in chronic obstructive lung disease (COPD). Oxygen administration using high flow nasal cannula (HFNC) has multiple physiological benefits in treating respiratory failure including reductions in PaCO₂ in a flow-dependent manner. We hypothesized that patients with COPD would develop worsening hypercapnia if oxygen fraction was increased without increasing flow rate. We evaluated the acute response to HFNC in subjects with severe COPD when flow remained constant and inspired oxygen was increased. In total, 11 subjects with severe COPD (FEV1 < 50%) on supplemental oxygen with baseline normocapnia (PaCO₂ < 45 mm Hg; n = 5) and hypercapnia (PaCO₂ ≥ 45 mm Hg; n = 6) were studied. Arterial blood gas responses were studied at three timepoints: Baseline, HFNC at a flow rate of 30 L/min at resting oxygen supplementation for 1 h, and FiO₂ 30% above baseline with the same flow rate for the next hour. The primary endpoint was the change in PaCO₂ from baseline. No significant changes in PaCO₂ were noted in response to HFNC applied at baseline FiO₂ in the normocapnic and hypercapnic group. At HFNC with FiO₂ 30% above baseline, the normocapnic group did not show a change in PaCO₂ (baseline: 38.9 ± 1.8 mm Hg; HFNC at higher FiO₂: 38.8 ± 3.1 mm Hg; p = 0.93), but the hypercapnic group demonstrated significant increase in PaCO₂ (baseline: 58.2 ± 9.3 mm Hg; HFNC at higher FiO₂: 63.3 ± 10.9 mm Hg; p = 0.025). We observed worsening hypercapnia in severe COPD patients and baseline hypercapnia who received increased oxygen fraction when flow remained constant. These data show the need for careful titration of oxygen therapy in COPD patients, particularly those with baseline hypercapnia when flow rate is unchanged.

The impact of changing patient interfaces on delivering aerosol with titrated oxygen in the high flow system

INTRODUCTION

Despite the widespread oxygen-culture as more is better in prehospital and hospital settings, the use of titrated oxygen-flow within a high-flow system can be beneficial especially when combined with aerosol-delivery and also save the patient from unnecessary-hyperoxia.

METHODS

Forty-five COPD patients were included in this study where they allocated in three-groups (nasal-delivery, oral-delivery, and oronasal-delivery groups). All patients were received their inhaled-salbutamol dose using Aerogen Solo nebuliser by one of the three interfaces, eg, nasal-cannula, mouthpiece, and facemask in two conditions; with oxygen-flow and without any oxygen-flow. Pulmonary and systemic salbutamol deposition was estimated by collecting two urine-samples from the patient; 30 min post-inhalation and cumulatively 24 hr post-inhalation. The quantity of salbutamol in these collected samples was measured by high-performance liquid chromatography. Lung function measurement was performed pre-bronchodilator inhalation and 30 min post-bronchodilator to estimate the change in pulmonary functions post-inhalation regarding all tested interfaces.

RESULTS

COPD patients showed the highest salbutamol percentage excreted 30 min post-inhalation of 5.7% (1.4) with mouthpiece interface when combined with oxygen at P < .002. While with the same condition using oxygen, valved-facemask showed the highest salbutamol percentage excreted in 24 hr post inhalation samples but the difference is only significantly compared with nasal cannula (P < .006). Moreover, without oxygen delivery, mouthpiece and valved facemask showed approximately the same salbutamol percentage excreted in 30 min post-inhalation samples, higher than that delivered by nasal cannula (P < .001). Of note, salbutamol delivery is significantly increased with oxygen flow for all interfaces (P < .05) except with nasal cannula.

CONCLUSIONS

The nasal cannula is a more comfortable and tolerable interface despite the lower fraction of the delivered drug compared with other tested interfaces. The use of oxygen-flow with aerosol delivery within a high flow system positively affects the delivered drug fraction and the pulmonary deposition of the drug.

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.

High-flow nasal cannula for acute exacerbation of chronic obstructive pulmonary disease: A systematic review and meta-analysis

BACKGROUND

The evidence for the safety of high-flow nasal cannula (HFNC) in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) patients is conflicting.

OBJECTIVES

To evaluate the intubation and mortality risks of HFNC compared to non-invasive ventilation (NIV) and conventional oxygen therapy (COT) for AECOPD patients.

METHODS

A search of electronic databases was performed. Studies that used HFNC to treat AECOPD patients were identified.

RESULTS

Seven RCTs and one observational study were included. There were no differences in intubation risk (risk ratio (RR) 0.94, 95% confidence interval (CI) 0.49 to 1.78, p = 0.84, very low certainty) and mortality risk (RR 0.91, 95% CI 0.46 to 1.79, p = 0.77, very low certainty) for HFNC compared with NIV. No data were available for intubation or mortality risk for HFNC compared with COT.

CONCLUSION

For AECOPD patients, low-quality evidence indicates that HFNC does not increase intubation and mortality risks compared to NIV.

High flow nasal therapy versus noninvasive ventilation as initial ventilatory strategy in COPD exacerbation: a multicenter non-inferiority randomized trial

Background

The efficacy and safety of high flow nasal therapy (HFNT) in patients with acute hypercapnic exacerbation of chronic obstructive pulmonary disease (AECOPD) are unclear. Our aim was to evaluate the short-term effect of HFNT versus NIV in patients with mild-to-moderate AECOPD, with the hypothesis that HFNT is non-inferior to NIV on CO₂ clearance after 2 h of treatment.

Methods

We performed a multicenter, non-inferiority randomized trial comparing HFNT and noninvasive ventilation (NIV) in nine centers in Italy. Patients were eligible if presented with mild-to-moderate AECOPD (arterial pH 7.25–7.35, PaCO₂ ≥ 55 mmHg before ventilator support). Primary endpoint was the mean difference of PaCO₂ from baseline to 2 h (non-inferiority margin 10 mmHg) in the per-protocol analysis. Main secondary endpoints were non-inferiority of HFNT to NIV in reducing PaCO₂ at 6 h in the per-protocol and intention-to-treat analysis and rate of treatment changes.

Results

Seventy-nine patients were analyzed (80 patients randomized). Mean differences for PaCO₂ reduction from baseline to 2 h were − 6.8 mmHg (± 8.7) in the HFNT and − 9.5 mmHg (± 8.5) in the NIV group (p = 0.404). By 6 h, 32% of patients (13 out of 40) in the HFNT group switched to NIV and one to invasive ventilation. HFNT was statistically non-inferior to NIV since the 95% confidence interval (CI) upper boundary of absolute difference in mean PaCO₂ reduction did not reach the non-inferiority margin of 10 mmHg (absolute difference 2.7 mmHg; 1-sided 95% CI 6.1; p = 0.0003). Both treatments had a significant effect on PaCO₂ reductions over time, and trends were similar between groups. Similar results were found in both per-protocol at 6 h and intention-to-treat analysis.

Conclusions

HFNT was statistically non-inferior to NIV as initial ventilatory support in decreasing PaCO₂ after 2 h of treatment in patients with mild-to-moderate AECOPD, considering a non-inferiority margin of 10 mmHg. However, 32% of patients receiving HFNT required NIV by 6 h. Further trials with superiority design should evaluate efficacy toward stronger patient-related outcomes and safety of HFNT in AECOPD.

Trial registration: The study was prospectively registered on December 12, 2017, in ClinicalTrials.gov (NCT03370666).

High-Flow Nasal Cannula for Chronic Obstructive Pulmonary Disease with Acute Compensated Hypercapnic Respiratory Failure: A Randomized, Controlled Trial

Introduction

Currently, there is a lack of evidence on the utilization of high-flow nasal cannula (HFNC) in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) accompanied by hypercapnic respiratory failure. We aimed to explore the efficacy and safety of HFNC compared with conventional oxygen therapy (COT) in such patients.

Methods

This was a prospective, randomized, controlled trial. Patients with AECOPD with a baseline arterial blood gas pH ≥7.35, PaO₂ <60 mmHg, and PaCO₂ >45 mmHg were enrolled. The primary endpoint was treatment failure, which needs mechanical ventilation.

Results

A total of 320 patients were randomized to either the HFNC group (n = 160) or the COT group (n = 160). Sixteen (10.0%) patients in the HFNC group had treatment failure during hospitalization, which was significantly lower than the COT group figure of 31 (19.4%) patients (p = 0.026). Twenty-four hours after recruitment, the PaCO₂ of the HFNC group was lower than that of the COT group (54.1 ± 9.79 mmHg vs 56.9 ± 10.1 mmHg, p = 0.030). PaCO₂ higher than 59 mmHg after HFNC for 24 h was identified as an independent risk factor for treatment failure [OR 1.078, 95% CI 1.006–1.154, p = 0.032].

Conclusion

In AECOPD patients with acute compensated hypercapnic respiratory failure, HFNC improved the prognosis compared with COT. Therefore, HFNC might be considered for first-line oxygen therapy in select patients.

Trial Registration Number

ClinicalTrials.Gov: NCT02439333.

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.

Efficiency of High-Flow Nasal Cannula on Pulmonary Rehabilitation in COPD Patients: A Meta-Analysis

Introduction

The clinical benefit of high-flow nasal cannula (HFNC) on factors related to pulmonary rehabilitation in chronic obstructive pulmonary disease (COPD) patients remains unclear. This meta-analysis aimed at synthesizing the available evidence on the efficacy of HFNC on exercise capacity, lung function, and other factors related to pulmonary rehabilitation in COPD patients.

Methods

Electronic databases (MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Web of Science) were searched for randomized trials comparing with conventional oxygen therapy (COT) or noninvasive ventilation (NIV). Primary outcomes were respiratory rate, FEV1, tidal volume, oxygen partial pressure, total score of St. George's respiratory questionnaire, 6-minute walk test, and exercise endurance time.

Results

Ten trials met the criteria for inclusion. Combined data from six studies showed that HFNC showed a lower respiratory rate in COPD patients [mean difference -1.27 (95% CI: -1.65–(-0.89)]. Combined data from three studies showed a lower forced expiratory volume in one second (FEV1) in the group of HFNC. No difference in tidal volume was showed between the HFNC and control groups in COPD patients. No significant oxygen improvement between the HFNC groups and control groups. The total score of St. George's respiratory questionnaire was improved by the subgroup analysis of HFNC versus COT but no NIV. Two multicenter RCTs showed the six-minute walk test, and statistical results showed that the length of the six-minute walk capacity was increased after usage of HFNC compared to the control group [mean difference -8.65 (95% CI: -9.12–(-8.19)]. No increase of exercise capacity after usage of HFNC (mean difference -12.65).

Conclusion

In the first meta-analysis of the area, the current evidence did not show so much positive effect on tidal volume or oxygen improvement in COPD patients. Length of the six-minute walk capacity was increased after using HFNC, while other pulmonary rehabilitation parameters, namely, the score of St. George's respiratory questionnaire and exercise capacity show no increase in the group of HFNC. The variance in the quality of the evidence included in this meta-analysis highlights the need for this evidence to be followed up with further high-quality and more randomized trials.

Tolerability and Safety of High-Flow Nasal Therapy in Patients Hospitalized with an Exacerbation of COPD

BACKGROUND

The effect of high-flow nasal therapy (HFNT) in individuals with an exacerbation of chronic obstructive pulmonary disease (COPD) and hypercapnia is not well studied. We assessed patient tolerance and impact of air-gas therapy delivered by humidified HFNT (20-35 L/min) on gas exchange in hypercapnic COPD patients during hospitalization for COPD exacerbation. We hypothesized that HFNT use would be safe and well tolerated in individuals hospitalized for COPD exacerbation regardless of the degree of hypercapnia.

METHODS

Patients hospitalized for a COPD exacerbation were included if they were hypercapnic (arterial partial pressure of carbon dioxide [PaCO2] > 45 mmHg), ≥ 10 pack-year history, and agreed to treatment with HFNT, along with daily arterial blood gas (ABG) samples and bedside spirometry. They were placed on a HFNT system following admission for at least 3 days with an air-gas blend to maintain a flow rate between 20-35 L/min and fraction of inspired oxygen (FiO2) titrated to keep oxygen saturation (SaO2) values > 90%. Patient tolerance of HFNT and evidence of clinical deterioration as defined by worsening hypoxia or hypercapnia was the primary endpoint.

RESULTS

Ten consecutive patients participated in the study. The patients had frequent prior exacerbations, were hypercapnic, dyspneic, and gas trapped. Participants received an air-gas flow rate (median [interquartile range (IQR)] 25 (IQR 20-30) L/min and FiO2 of 30 (IQR 30-30) %. There was no increase in PaCO2- levels (p = 0.26) or dyspnea (Borg scale, p= 0.52) while using HFNT. No patient discontinued HFNT, had further decompensation, required non-invasive ventilation or intubation during the study period.

CONCLUSION

In a pilot study, patients experiencing a severe COPD exacerbation were able to tolerate continuous HFNT safely regardless of degree of hypercapnia.

Treatment of severe stable COPD: the multidimensional approach of treatable traits

Now that additional treatment options for severe chronic obstructive pulmonary disease (COPD) have emerged in recent years, patients with severe COPD should not be left in the rather hopeless situation of “there is nothing to improve” any more. Inertia or fatalism is a disservice to our patients. Ranging from advanced care planning to quite intense and demanding therapies such as multidisciplinary pulmonary rehabilitation, (endoscopic) lung volume reduction, chronic noninvasive ventilation and lung transplantation, caregivers should try to provide a personalised treatment for every severe COPD patient. In this review, we aim to describe the multidimensional approach to these patients at our centre along the lines of treatable traits leading to specific additional treatment modalities on top of standard care.

Severe COPD is not hopeless; in light of treatment options such as pulmonary rehabilitation, bronchoscopic lung volume reduction, chronic noninvasive ventilation and lung transplantation, every patient deserves a personalised assessment of treatable traitshttps://bit.ly/2TO7jxB

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.

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

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

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.

High-flow nasal cannula oxygen therapy in acute respiratory failure at Emergency Departments: A systematic review

OBJECTIVES

The use of high-flow oxygen therapy (HFOT) through nasal cannula for the management of acute respiratory failure at the emergency department (ED) has been only sparsely studied. We conducted a systematic review of randomized-controlled and quasi-experimental studies comparing the early use of HFOT versus conventional oxygen therapy (COT) in patients with acute respiratory failure admitted to EDs.

METHODS

A systematic research of literature was carried out for all published control trials comparing HFOT with COT in adult patients admitted in EDs. Eligible data were extracted from Medline, Embase, Pascal, Web of Science and the Cochrane database. The primary outcome was the need for mechanical ventilation, i.e. intubation or non-invasive ventilation as rescue therapy. Secondary outcomes included respiratory rate, dyspnea level, ED length of stay, intubation and mortality.

RESULTS

Out of 1829 studies screened, five studies including 673 patients were retained in the analysis (350 patients treated with HFOT and 323 treated with COT). The need for mechanical ventilation was similar in both treatments (RR = 0.75; 95% CI 0.41 to 1.35; P = 0.31; I² = 16%). Respiratory rate was lower with HFOT (Mean difference (MD) = -3.14 breaths/min; 95% CI = -4.9 to -1.4; P < 0.001; I² = 39%), whereas sensation of dyspnea did not differ. (MD = -1.04; 95% CI = -2.29 to -0.22; P = 0.08; I² = 67%). ED length of stay and mortality were similar between groups.

CONCLUSION

The early use of HFOT in patients admitted to an ED for acute respiratory failure did not reduce the need for mechanical ventilation as compared to COT. However, HFOT decreased respiratory rate.

REGISTRATION

PROSPERO ID CRD42019125696.

High Flow Through Nasal Cannula in Stable and Exacerbated Chronic Obstructive Pulmonary Disease Patients

BACKGROUND

High-Flow through Nasal Cannula (HFNC) is a system delivering heated humidified air-oxygen mixture at a flow up to 60 L/min. Despite increasing evidence in hypoxemic acute respiratory failure, a few is currently known in chronic obstructive pulmonary disease (COPD) patients.

OBJECTIVE

To describe the rationale and physiologic advantages of HFNC in COPD patients, and to systematically review the literature on the use of HFNC in stable and exacerbated COPD patients, separately.

METHODS

A search strategy was launched on MEDLINE. Two authors separately screened all potential references. All (randomized, non-randomized and quasi-randomized) trials dealing with the use of HFNC in both stable and exacerbated COPD patients in MEDLINE have been included in the review.

RESULTS

Twenty-six studies have been included. HFNC: 1) provides heated and humidified airoxygen admixture; 2) washes out the anatomical dead space of the upper airway; 3) generates a small positive end-expiratory pressure; 4) guarantees a more stable inspired oxygen fraction, as compared to conventional oxygen therapy (COT); and 5) is more comfortable as compared to both COT and non-invasive ventilation (NIV). In stable COPD patients, HFNC improves gas exchange, the quality of life and dyspnea with a reduced cost of muscle energy expenditure, compared to COT. In exacerbated COPD patients, HFNC may be an alternative to NIV (in case of intolerance) and to COT at extubation or NIV withdrawal.

CONCLUSION

Though evidence of superiority still lacks and further studies are necessary, HFNC might play a role in the treatment of both stable and exacerbated COPD patients.

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

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

Clinical Evidence of Nasal High-Flow Therapy in Chronic Obstructive Pulmonary Disease Patients

Nasal high-flow therapy (NHFT) is an upcoming treatment for chronic obstructive pulmonary disease (COPD) patients. It supplies heated, humidified, and, desirably, oxygen-enriched air through a nasal cannula at flow rates up to 60 L/min. Several studies examined the effect of NHFT in COPD patients, but a clear overview is lacking. The present review aimed to give an overview of the clinical evidence of NHFT in 3 aspects of COPD care: long-term use in stable COPD patients, use for treatment of COPD exacerbations, and use during exercise therapy in COPD. For each topic, a specific literature search was performed up to December 9, 2019. Studies show promising results, with most evidence for its long-term use in hypoxemic COPD patients that frequently exacerbate, and very limited evidence for its use during COPD exacerbations or as a worthwhile adjunct to exercise training. More evidence is therefore needed to know how to incorporate NHFT in standard clinical practice.

Nasal High Flow Use in COPD Patients with Hypercapnic Respiratory Failure: Treatment Algorithm & Review of the Literature

Nasal high flow (NHF) therapy has recently gained attention as a new respiratory support system and is increasingly being utilized in every day clinical practice. Recent studies suggest that it may also be effective in patients with hypercapnia and suggest NHF as a possible alternative for patients who cannot tolerate standard noninvasive ventilation. The present review discusses the mechanisms of action that make NHF potentially suitable for chronic obstructive pulmonary disease (COPD) patients and evaluates the current evidence of NHF use for treatment of stable hypercapnic COPD patients as well as acute hypercapnic exacerbation of COPD. An algorithm is also proposed for the clinical application of NHF in patients with acute hypercapnic exacerbation of COPD, based on current literature.