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Abstract Background Optimal flow settings during high-flow nasal cannula (HFNC) therapy are unknown. We investigated the optimal flow settings during HFNC therapy based on breathing pattern and tidal inspiratory flows in patients with acute hypoxemic respiratory failure (AHRF). Methods We conducted a prospective clinical study in adult hypoxemic patients treated by HFNC with a fraction of inspired oxygen (FIO2) ≥ 0.4. Patient’s peak tidal inspiratory flow (PTIF) was measured and HFNC flows were set to match individual PTIF and then increased by 10 L/min every 5–10 min up to 60 L/min. FIO2 was titrated to maintain pulse oximetry (SpO2) of 90–97%. SpO2/FIO2, respiratory rate (RR), ROX index [(SpO2/FIO2)/RR], and patient comfort were recorded after 5–10 min on each setting. We also conducted an in vitro study to explore the relationship between the HFNC flows and the tracheal FIO2, peak inspiratory and expiratory pressures. Results Forty-nine patients aged 58.0 (SD 14.1) years were enrolled. At enrollment, HFNC flow was set at 45 (38, 50) L/min, with an FIO2 at 0.62 (0.16) to obtain an SpO2/FIO2 of 160 (40). Mean PTIF was 34 (9) L/min. An increase in HFNC flows up to two times of the individual patient’s PTIF, incrementally improved oxygenation but the ROX index plateaued with HFNC flows of 1.34–1.67 times the individual PTIF. In the in vitro study, when the HFNC flow was set higher than PTIF, tracheal peak inspiratory and expiratory pressures increased as HFNC flow increased but the FIO2 did not change. Conclusion Mean PTIF values in most patients with AHRF were between 30 and 40 L/min. We observed improvement in oxygenation with HFNC flows set above patient PTIF. Thus, a pragmatic approach to set optimal flows in patients with AHRF would be to initiate HFNC flow at 40 L/min and titrate the flow based on improvement in ROX index and patient tolerance. Trial registration: ClinicalTrials.gov (NCT03738345). Registered on November 13th, 2018. https://clinicaltrials.gov/ct2/show/NCT03738345?term=NCT03738345&draw=2&rank=1

Abstract Objective Critically ill patients admitted in ICU because of COVID-19 infection display severe hypoxemic respiratory failure. The Surviving Sepsis Campaign recommends oxygenation through high-flow nasal cannula over non-invasive ventilation. The primary outcome of our study was to evaluate the effect of the addition of a surgical mask on a high-flow nasal cannula system on oxygenation parameters in hypoxemic COVID-19 patients admitted in ICU who do not require urgent intubation. The secondary outcomes were relevant changes in PaCO2 associated with clinical modifications and patient’s feelings. Design We prospectively assessed 21 patients admitted in our mixed Intensive Care Unit of the Cliniques Universitaires Saint Luc. Main results While FiO2 was unchanged, we demonstrate a significant increase of PaO2 (from 59 (± 6), to 79 mmHg (± 16), p

Background: Optimal flow settings during high-flow nasal cannula (HFNC) therapy are unknown. We investigated the optimal flow settings during HFNC therapy based on breathing pattern and tidal inspiratory flows in patients with acute hypoxemic respiratory failure (AHRF). Methods: We conducted a prospective clinical study in adult hypoxemic patients treated by HFNC with a fraction of inspired oxygen (FIO2) ≥ 0.4. Patient's peak tidal inspiratory flow (PTIF) was measured and HFNC flows were set to match individual PTIF and then increased by 10 L/min every 5–10 min up to 60 L/min. FIO2 was titrated to maintain pulse oximetry (SpO2) of 90–97%. SpO2/FIO2, respiratory rate (RR), ROX index [(SpO2/FIO2)/RR], and patient comfort were recorded after 5–10 min on each setting. We also conducted an in vitro study to explore the relationship between the HFNC flows and the tracheal FIO2, peak inspiratory and expiratory pressures. Results: Forty-nine patients aged 58.0 (SD 14.1) years were enrolled. At enrollment, HFNC flow was set at 45 (38, 50) L/min, with an FIO2 at 0.62 (0.16) to obtain an SpO2/FIO2 of 160 (40). Mean PTIF was 34 (9) L/min. An increase in HFNC flows up to two times of the individual patient's PTIF, incrementally improved oxygenation but the ROX index plateaued with HFNC flows of 1.34–1.67 times the individual PTIF. In the in vitro study, when the HFNC flow was set higher than PTIF, tracheal peak inspiratory and expiratory pressures increased as HFNC flow increased but the FIO2 did not change. Conclusion: Mean PTIF values in most patients with AHRF were between 30 and 40 L/min. We observed improvement in oxygenation with HFNC flows set above patient PTIF. Thus, a pragmatic approach to set optimal flows in patients with AHRF would be to initiate HFNC flow at 40 L/min and titrate the flow based on improvement in ROX index and patient tolerance. Trial registration: ClinicalTrials.gov (NCT03738345). Registered on November 13th, 2018. https://clinicaltrials.gov/ct2/show/NCT03738345?term=NCT03738345&draw=2&rank=1 [ABSTRACT FROM AUTHOR]

Abstract Background The outbreak of a novel coronavirus (2019-nCoV)-infected pneumonia (NCIP) is currently ongoing in China. Most of the critically ill patients received high-flow nasal cannula (HFNC) oxygen therapy. However, the experience of HFNC in this population is lacking. Methods We retrospectively screened 318 confirmed patients with NCIP in two hospitals of Chongqing, China, from January 1st to March 4th, 2020. Among them, 27 (8.4%) patients experienced severe acute respiratory failure including 17 patients (63%) treated with HFNC as first-line therapy, 9 patients (33%) treated with noninvasive ventilation (NIV) and one patient (4%) treated with invasive ventilation. HFNC failure was defined by the need of NIV or intubation as rescue therapy. Results Of the 17 HFNC patients, 7 (41%) experienced HFNC failure. The HFNC failure rate was 0% (0/6) in patients with PaO2/FiO2 > 200 mm Hg vs. 63% (7/11) in those with PaO2/FiO2 ≤ 200 mm Hg (p = 0.04). Compared with baseline data, the respiratory rate significantly decreased after 1–2 h of HFNC in successful group [median 26 (IQR: 25–29) vs. 23 (22–25), p = 0.03]. However, it did not in the unsuccessful group. After initiation of NIV as rescue therapy among the 7 patients with HFNC failure, PaO2/FiO2 significantly improved after 1–2 h of NIV [median 172 (150–208) mmHg vs. 114 (IQR: 79–130) under HFNC, p = 0.04]. However, two out of seven (29%) patients with NIV as rescue therapy ultimately received intubation. Among the 27 patients with severe acute respiratory failure, four patients were eventually intubated (15%). Conclusions Our study indicated that HFNC was the most common ventilation support for patients with NCIP. Patients with lower PaO2/FiO2 were more likely to experience HFNC failure.

Abstract Background Despite the extensive use of high-flow nasal cannula (HFNC) therapy in intensive care units (ICU) for acute respiratory failure (ARF), its daily clinical practice has not been assessed. We designed a regional survey in ICUs in North-west France to evaluate ICU physicians’ clinical practice with HFNC. Materials and methods We sent an observational survey to ICU physicians from 34 French ICUs over a 6-month period in 2016–2017. The survey included questions regarding the indications and expected efficiency of HFNC, practical aspects of use (initiation, weaning) and satisfaction. Comparisons between junior and senior ICU physicians were performed using a Fischer exact test. Results Among the 235 ICU physicians contacted, 137 responded (58.3%) all of whom regularly used HFNC. Hypoxemic ARF was considered a good indication for HFNC by all 137, but only 30% expected HFNC success (i.e., avoiding intubation in at least 60% of cases). Among hypoxemic indications, 30% of juniors considered acute pulmonary edema a good indication versus 74% of seniors (p

Abstract Background Asthma is the most common obstructive airway disease in children and adults. Nasal high flow (NHF) is a recent device that is now used as a primary support for respiratory distress. Several studies have reported use of NHF as a respiratory support in status asthmaticus; however, there are no data to recommend such practice. We therefore conducted this preliminary study to evaluate NHF therapy for children with status asthmaticus admitted to our PICU in order to prepare a multicentre randomized controlled study. Results Between November 2009 and January 2014, 73 patients with status asthmaticus were admitted to the PICU, of whom 39 (53%) were treated with NHF and among these 10 (26%) presented severe acidosis at admission (pH

Background: The outbreak of a novel coronavirus (2019-nCoV)-infected pneumonia (NCIP) is currently ongoing in China. Most of the critically ill patients received high-flow nasal cannula (HFNC) oxygen therapy. However, the experience of HFNC in this population is lacking. Methods: We retrospectively screened 318 confirmed patients with NCIP in two hospitals of Chongqing, China, from January 1st to March 4th, 2020. Among them, 27 (8.4%) patients experienced severe acute respiratory failure including 17 patients (63%) treated with HFNC as first-line therapy, 9 patients (33%) treated with noninvasive ventilation (NIV) and one patient (4%) treated with invasive ventilation. HFNC failure was defined by the need of NIV or intubation as rescue therapy. Results: Of the 17 HFNC patients, 7 (41%) experienced HFNC failure. The HFNC failure rate was 0% (0/6) in patients with PaO2/FiO2 > 200 mm Hg vs. 63% (7/11) in those with PaO2/FiO2 ≤ 200 mm Hg (p = 0.04). Compared with baseline data, the respiratory rate significantly decreased after 1–2 h of HFNC in successful group [median 26 (IQR: 25–29) vs. 23 (22–25), p = 0.03]. However, it did not in the unsuccessful group. After initiation of NIV as rescue therapy among the 7 patients with HFNC failure, PaO2/FiO2 significantly improved after 1–2 h of NIV [median 172 (150–208) mmHg vs. 114 (IQR: 79–130) under HFNC, p = 0.04]. However, two out of seven (29%) patients with NIV as rescue therapy ultimately received intubation. Among the 27 patients with severe acute respiratory failure, four patients were eventually intubated (15%). Conclusions: Our study indicated that HFNC was the most common ventilation support for patients with NCIP. Patients with lower PaO2/FiO2 were more likely to experience HFNC failure. [ABSTRACT FROM AUTHOR]

Background: Asthma is the most common obstructive airway disease in children and adults. Nasal high flow (NHF) is a recent device that is now used as a primary support for respiratory distress. Several studies have reported use of NHF as a respiratory support in status asthmaticus; however, there are no data to recommend such practice. We therefore conducted this preliminary study to evaluate NHF therapy for children with status asthmaticus admitted to our PICU in order to prepare a multicentre randomized controlled study. Results: Between November 2009 and January 2014, 73 patients with status asthmaticus were admitted to the PICU, of whom 39 (53%) were treated with NHF and among these 10 (26%) presented severe acidosis at admission (pH < 7.30). Thirty-four less severe children (41%) were treated with standard oxygen. For one child (2.6%) NHF failed and was then switched to non-invasive ventilation. NHF was discontinued in another patient because of the occurrence of pneumothorax after 31 h with NHF; the patient was then switched to standard oxygen therapy. Mean ± SD heart rate (165 ± 21 vs. 141 ± 25/min, p < 0.01) and respiratory rate (40 ± 13 vs. 31 ± 8/min, p < 0.01) decreased significantly, and blood gas improved in the first 24 h. In the subgroup of patients with acidosis, median [IQR] pH increased significantly between hour 0 and 2 (7.25 [7.21-7.26] vs. 7.30 [7.27-7.33], p = 0.009) and median [IQR] pCO decreased significantly (7.27 kPa [6.84-7.91 vs. 5.85 kPa [5.56-6.11], p = 0.007). No patient was intubated. Conclusion: This retrospective study showed the feasibility and safety of NHF in children with severe asthma. Blood gas and clinical parameters were significantly improved during the first 24 h. NHF failed in only two patients, and none required invasive ventilation. [ABSTRACT FROM AUTHOR]

Objective: Critically ill patients admitted in ICU because of COVID-19 infection display severe hypoxemic respiratory failure. The Surviving Sepsis Campaign recommends oxygenation through high-flow nasal cannula over non-invasive ventilation. The primary outcome of our study was to evaluate the effect of the addition of a surgical mask on a high-flow nasal cannula system on oxygenation parameters in hypoxemic COVID-19 patients admitted in ICU who do not require urgent intubation. The secondary outcomes were relevant changes in PaCO2 associated with clinical modifications and patient's feelings. Design: We prospectively assessed 21 patients admitted in our mixed Intensive Care Unit of the Cliniques Universitaires Saint Luc. Main results: While FiO2 was unchanged, we demonstrate a significant increase of PaO2 (from 59 (± 6), to 79 mmHg (± 16), p < 0.001), PaO2/FiO2 from 83 (± 22), to 111 (± 38), p < 0.001) and SaO2 (from 91% (± 1.5), to 94% (± 1.6), p < 0.001), while the patients were under the surgical mask. The SpO2 returned to pre-treatment values when the surgical mask was removed confirming the effect of the device rather than a spontaneous positive evolution. Conclusion: A surgical mask placed on patient's face already treated by a High-flow nasal cannula device improves COVID-19 patient's oxygenation admitted in Intensive Care Unit for severe hypoxemic respiratory failure without any clinically relevant side. [ABSTRACT FROM AUTHOR]

Background: Despite the extensive use of high-flow nasal cannula (HFNC) therapy in intensive care units (ICU) for acute respiratory failure (ARF), its daily clinical practice has not been assessed. We designed a regional survey in ICUs in North-west France to evaluate ICU physicians' clinical practice with HFNC. Materials and methods: We sent an observational survey to ICU physicians from 34 French ICUs over a 6-month period in 2016–2017. The survey included questions regarding the indications and expected efficiency of HFNC, practical aspects of use (initiation, weaning) and satisfaction. Comparisons between junior and senior ICU physicians were performed using a Fischer exact test. Results: Among the 235 ICU physicians contacted, 137 responded (58.3%) all of whom regularly used HFNC. Hypoxemic ARF was considered a good indication for HFNC by all 137, but only 30% expected HFNC success (i.e., avoiding intubation in at least 60% of cases). Among hypoxemic indications, 30% of juniors considered acute pulmonary edema a good indication versus 74% of seniors (p < 0.0001). Hypercapnic ARF was considered a good indication by 33% with only 2% expecting HFNC success. A need for conventional oxygen therapy ≥ 6 L/min justified HFNC therapy for 40% and ≥ 9 L/min for 39% of responders. 58% of ICU physicians started HFNC therapy with a FiO2 ≥ 50% and 28% with a gas flow ≥ 50 L/min. Practices for HFNC weaning were heterogeneous: 48% considered a FiO2 ≤ 30%; whereas, 30% considered a FiO2 ≤ 30% with a high flow ≤ 20 L/min. Criteria for HFNC failure (i.e., need for intubation) were ventilatory pauses or arrest (97%), persistent hypoxemia (95%), respiratory acidosis (81%), worsening of breathing (95%, 100% of seniors and 86% of juniors, p = 0.003), bronchial congestion (75%) and circulatory failure (61%, 72% of seniors and 44% of juniors, p = 0.007). Conclusion: HFNC is used by ICU physicians in many situations of ARF, despite their relatively low expectations of success, especially in cases of hypercapnia. Clinical practices appear somewhat heterogeneous. Despite the physiological benefit of HFNC, further prospective observational studies are still required on HFNC outcomes and daily practices. [ABSTRACT FROM AUTHOR]