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).

In pressure support ventilation, deep propofol sedation increased asynchronies, while light sedation did not. Propofol reduced the respiratory drive, while breathing timing was not significantly affected. Gas exchange and breathing pattern were also influenced by propofol infusion to an extent that varied with the depth of sedation and the mode of ventilation.

BackgroundHigh-flow nasal cannula (HFNC) has become a frequently used non-invasive form of respiratory support in acute settings, however evidence supporting its use has only recently emerged. These guidelines provide evidence-based recommendations for the use of HFNC alongside other noninvasive forms of respiratory support in adults with acute respiratory failure (ARF).Materials and methodologyThe European Respiratory Society Task Force panel included expert clinicians and methodologists in pulmonology and intensive care medicine. The Task Force used the GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) methods to summarise evidence and develop clinical recommendations for the use of HFNC alongside conventional oxygen therapy (COT) and non-invasive ventilation (NIV) for the management of adults in acute settings with ARF.ResultsThe Task Force developed 8 conditional recommendations, suggesting using: 1) HFNC over COT in hypoxemic ARF, 2) HFNC over NIV in hypoxemic ARF, 3)HFNC over COT during breaks from NIV, 4) either HFNC or COT in post-operative patients at low risk of pulmonary complications, 5) either HFNC or NIV in post-operative patients at high risk of pulmonary complications, 6) HFNC over COT in non-surgical patients at low risk of extubation failure, 7) NIV over HFNC for patients at high risk of extubation failure unless there are relative or absolute contraindications to NIV, 8) trialling NIV prior to use of HFNC in patients with chronic obstructive pulmonary disease (COPD) and hypercapnic ARF.ConclusionsHFNC is a valuable intervention in adults with ARF. These conditional recommendations can assist clinicians in choosing the most appropriate form of non-invasive respiratory support to provide to patients in different acute settings.

Objectives: Assessing gas exchange, diaphragm function, respiratory rate, and patient comfort during high-flow oxygen therapy and standard oxygen at the time of noninvasive ventilation discontinuation. Design: Randomized crossover physiologic study. Setting: Two ICUs. Patients: Thirty chronic obstructive pulmonary disease patients with hypercapnic acute respiratory failure receiving noninvasive ventilation greater than 24 hours. Interventions: All patients underwent five 30-minute trials, the first, third, and fifth trial in noninvasive ventilation, whereas the second and fourth were randomly conducted with either standard oxygen and high-flow oxygen therapy. Measurements and Main Results: Diaphragm displacement and thickening fraction were determined by sonographic evaluation at the end of each trial. Arterial blood gases, respiratory rate, and patient comfort were also assessed. Paco 2 (p = 0.153) and pH (p = 0.114) were not different among trials, while Pao 2 was greater in noninvasive ventilation than with both standard oxygen (p ≤ 0.005) and high-flow oxygen therapy (p ≤ 0.001). The diaphragm displacement was no different among trials (p = 0.875), while its thickening fraction was greater with standard oxygen, compared with high-flow oxygen therapy and all noninvasive ventilation trials (p < 0.001 for all comparisons), without differences between high-flow oxygen therapy and noninvasive ventilation. Respiratory rate also increased with standard oxygen, compared with both high-flow oxygen therapy (p < 0.001) and noninvasive ventilation (p < 0.01). High-flow oxygen therapy improved comfort, compared with standard oxygen (p = 0.004) and noninvasive ventilation (p < 0.001). Conclusions: At the time of noninvasive ventilation interruption, Paco 2 and diaphragm displacement remained unchanged regardless of the modality of oxygen administration. However, although standard oxygen resulted in a remarkable increase in diaphragm thickening fraction, high-flow oxygen therapy allowed maintaining it unchanged, while improving patient comfort.