High-Flow Nasal Cannula Liberation: Who, When, and How?

Controversies in airway management of COVID-19 patients: updated information and international expert consensus recommendations

In immunocompromised patients with acute respiratory failure, invasive mechanical ventilation remains associated with high mortality. Choosing the adequate oxygenation strategy is of the utmost importance in that setting. High-flow nasal oxygen has recently shown survival benefits in unselected patients with acute respiratory failure. The objective was to assess outcomes of immunocompromised patients with hypoxemic acute respiratory failure treated with high-flow nasal oxygen. We performed a post hoc analysis of a randomized controlled trial of noninvasive ventilation in critically ill immunocompromised patients with hypoxemic acute respiratory failure. Twenty-nine ICUs in France and Belgium. Critically ill immunocompromised patients with hypoxemic acute respiratory failure. A propensity score-based approach was used to assess the impact of high-flow nasal oxygen compared with standard oxygen on day 28 mortality. Among 374 patients included in the study, 353 met inclusion criteria. Underlying disease included mostly malignancies (n = 296; 84%). Acute respiratory failure etiologies were mostly pneumonia (n = 157; 44.4%) or opportunistic infection (n = 76; 21.5%). Noninvasive ventilation was administered to 180 patients (51%). Invasive mechanical ventilation was ultimately needed in 142 patients (40.2%). Day 28 mortality was 22.6% (80 deaths). Throughout the ICU stay, 127 patients (36%) received high-flow nasal oxygen whereas 226 patients received standard oxygen. Ninety patients in each group (high-flow nasal oxygen or standard oxygen) were matched according to the propensity score, including 91 of 180 (51%) who received noninvasive ventilation. High-flow nasal oxygen was neither associated with a lower intubation rate (hazard ratio, 0.42; 95% CI, 0.11-1.61; p = 0.2) nor day 28 mortality (hazard ratio, 0.80; 95% CI, 0.45-1.42; p = 0.45). In immunocompromised patients with hypoxemic acute respiratory failure, high-flow nasal oxygen when compared with standard oxygen did not reduce intubation or survival rates. However, these results could be due to low statistical power or unknown confounders associated with the subgroup analysis. A randomized trial is needed.

Objective: To investigate the efficacy of high flow nasal cannula (HFNC) in children with acute respiratory failure. Methods: A prospective study was conducted. A total of 153 patients aged from 1 to 14 years with acute respiratory failure were enrolled, who were admitted to pediatric intensive care unit (PICU) of Shanghai Children's Hospital from January 2018 to December 2019. HFNC success was defined as no need for invasive mechanical ventilation and successfully withdrawn from HFNC, while HFNC failure was defined as need for invasive mechanical ventilation. HFNC at a flow rate of 2 L/(kg·min) (maximum ≤ 60 L/min) with inhaled oxygen concentration (FiO2) between 0.30 and 1.00 was applied to maintain percutaneous oxygen saturation (SpO2) of 0.94-0.97. Parameters including arterial partial pressure of oxygen (PaO2), partial pressure of carbon dioxide in artery (PaCO2), SpO2 and PaO2/FiO2 were collected before and during the application of HFNC at 1 h, 6 h, 12 h, 24 h and 48 h, as well as over 48 h after HFNC withdrawn. Comparison between the groups was performed by student t test, Mann-Whitney U test or chi-square test. The sensitivity and specificity of the above parameters in predicting HFNC success were evaluated by receiver operating characteristic (ROC) curve. Results: A total of 153 children (70 males and 83 females) were enrolled. Among them, 131 (85.6%) cases were successfully weaned off from HFNC and 22 (14.4%) failed. The duration of HFNC was 57 (38, 95) hours in the successful group, and the PaO2/FiO2 before HFNC application and after HFNC was withdrawn were 187 (170, 212) mmHg (1 mmHg=0.133 kPa) and 280 (262, 292) mmHg, respectively. The duration of HFNC in the failure group was 19 (9, 49) hours, and the PaO2/FiO2 before HFNC application and after HFNC withdrawn were 176 (171, 189) mmHg and 159 (156, 161) mmHg, respectively. The values of PaO2/FiO2 were significantly higher in the successful group than those in the failed group at using HFNC initially 1 h (196 (182, 211) vs. 174 (160, 178) mmHg, Z =-5.105, P<0.01), 6 h (213 (203, 220) vs. 168 (157, 170) mmHg, Z =-6.772, P<0.01), 12 h (226 (180, 261) vs. 165 (161, 170) mmHg, Z =-4.308, P<0.01), 24 h (229 (195, 259) vs. 165 (161, 170) mmHg, Z=-4.609, P<0.01) and 48 h (249 (216, 273) vs. 163 (158, 169) mmHg, Z =-4.628, P<0.01) after the HFNC application, and over 48 h after HFNC was withdrawn (277 (268, 283) vs. 157 (154, 158) mmHg, Z=-3.512, P<0.01). Moreover, the PaO2 levels were significantly higher in the successful group than those in the failed group using HFNC initially at 1 h (73.7 (71.0, 76.7) vs. 70.0 (66.2, 71.2) mmHg, Z=-4.587, P<0.01) and 6 h (79.0 (75.0, 82.0) vs. 71.0 (62.0, 72.0) mmHg, Z=-5.954, P<0.01) after HFNC application. Also, the SpO2 levels showed the same differences at 1 h (0.96 (0.95, 0.96) vs. 0.94 (0.92, 0.94), Z =-4.812, P<0.01) and 6 h (0.96 (0.95, 0.97) vs. 0.94(0.91, 0.95), Z=-5.024, P<0.01) after HFNC application. Forty eight hours after HFNC was withdrawn, the PaO2 (88.0 (81.7, 95.0) vs. 63.7 (63.3, 66.0) mmHg, Z =-3.032, P<0.01) and SpO2 (0.96 (0.94, 0.98) vs. 0.91 (0.90, 0.92), Z=-3.957, P<0.01) were also significantly higher in the successful group. Regarding the HFNC complications, there was one case with atelectasis and one with pneumothorax in the failure group. HFNC was used as sequential oxygen therapy after extubation in 79 children, successful in all. ROC curve showed that the area under curve of PaO2/FiO2 in predicting HFNC success was 0.990, and the optimal cut-off value was 232 mmHg with the 95%CI of 0.970-1.000 (P<0.01). Conclusions: HFNC could be used as a respiratory support strategy for children with mild to moderate respiratory failure and as a sequential oxygen therapy after extubation. The PaO2/FiO2 when HFNC withdrow is the optimal index to evaluate the success of HFNC application.

Objective To determine the efficacy of sequential therapy with high-flow nasal cannula oxygen in patients with acute respiratory failure. Methods Acute respiratory failure patients admitted to department of Crititcal Care Medicine of Affiliated Hospital of Nantong University who received mechanical ventilation from January 2016 to December 2017 were enrolled in this study. After extubation, 44 patients were randomly divided into control group while 45 others in high flow oxygen group. The control group was given conventional oxygen therapy (nasal catheter or mask), and high flow group was treated with high-flow nasal cannula oxygen. Respiratory rate, PaO2/FiO2, SaO2 and PaCO2 of patients at 1h, 8h and 24h after extubation between two groups were recorded. We also recorded the comfort level and tolerance of oxygen therapy, the proportion of noninvasive ventilation and re-intubation between two groups. Results The respiratory rate ( per minute) was significantly lower in the high-flow oxygen group [1 h: (20.6±3.2) times/min vs (24.5±3.7) times/min; 8 h: (21.5±3.6) times/min vs (20.6±3.2) times/min; 24 h: (20.9±3.4) times/min vs (24.9±4.2) times/min, all P 0.05). Conclusion In patients with acute respiratory failure after extubation, treatment with high-flow oxygen can improveoxygenationwith better comfort and tolerance. Also it can reduce the use of noninvasive mechanical ventilation in patients. The findings support the use of high-flow nasal oxygen therapy as sequential therapy after extubation in patients with acute respiratory failure. Key words: High-flow nasal cannula oxygen therapy; Acute respiratory failure; Sequential therapy

Objective To compare the clinical effects of high flow nasal cannula (HFNC) and non-rebreathing oxygen face mask(NRB) in post-extubation patients. Methods 88 critically ill patients with machinery ventilations were divided into HFNC group and NRB group randomly. Blood gas analysis and hemodynamic parameters were assessed 1 hour prior to extubation and 6 hours after extubation. The primary clinical outcomes measured were ventilation-free days, re-intubation patient numbers, length of stay in ICU(Intensive Care Unite) , total duration of hospitalization and mortality. The scant of breath degree and comfortableness of patient were recorded according to the Visual analogue scale. The measurement data were described by mean±standard deviation (±s) and analyzed with t test, enumeration data were described by number of cases and composition ratio and analyzed with χ2test, P<0.05 was considered to have statistical difference. Results There was no significant difference in clinical features between the two groups, The oxygenation index of HFNC group is significantly higher than that of NRB group after extubation [(251.4±43.9) vs.(201.7±60.7), P=0.037)]. There were more ventilator-free days in the HFNC group than NRB group [(4.2± 2.1) vs.(3.4±2.8), P=0.037)] and fewer patients required re-intubation(P=0.028). The rate of ventilator associated pneumonia is also lower than NRB group(P=0.024). The patients’ scant of breath feeling were obviously allevated comparing with the NRB group [(2.9±1.1) vs.(3.7±1.8), P=0.042)]. The oxygenation index of NRB group significantly decreased after extubation[(242.9±68.4vs.201.7±60.7 P=0.048)]. The two groups demonstrated similar hemodynamic patterns before and after extubation. And there were no statistically significant clinical differences in PaCO2, length of ICU stay, total duration of hospitalization or mortality. Conclusions Compared with NRB, HFNC is a more safe and effective clinical tool in the prevention and treatment of critical adult patients with extubation failure. Key words: High flow nasal cannula (HFNC); Non-rebreathing oxygen face mask (NRB); Post-extubation respiratory failure; Mechanical ventilation; Extubation; Curative effect

BackgroundCritically ill patients with obesity may have an increased risk of difficult intubation and subsequent severe hypoxemia. We hypothesized that pre-oxygenation with noninvasive ventilation before intubation as compared with high-flow nasal cannula oxygen may decrease the risk of severe hypoxemia in patients with obesity.MethodsPost hoc subgroup analysis of critically ill patients with obesity (body mass index ≥ 30 kg·m−2) from a multicenter randomized controlled trial comparing preoxygenation with noninvasive ventilation and high-flow nasal oxygen before intubation of patients with acute hypoxemic respiratory failure (PaO2/FiO2 < 300 mm Hg). The primary outcome was the occurrence of severe hypoxemia (pulse oximetry < 80%) during the intubation procedure.ResultsAmong the 313 patients included in the original trial, 91 (29%) had obesity with a mean body mass index of 35 ± 5 kg·m−2. Patients with obesity were more likely to experience an episode of severe hypoxemia during intubation procedure than patients without obesity: 34% (31/91) vs. 22% (49/222); difference, 12%; 95% CI 1 to 23%; P = 0.03. Among patients with obesity, 40 received preoxygenation with noninvasive ventilation and 51 with high-flow nasal oxygen. Severe hypoxemia occurred in 15 patients (37%) with noninvasive ventilation and 16 patients (31%) with high-flow nasal oxygen (difference, 6%; 95% CI − 13 to 25%; P = 0.54). The lowest pulse oximetry values during intubation procedure were 87% [interquartile range, 77–93] with noninvasive ventilation and 86% [78–92] with high-flow nasal oxygen (P = 0.98). After multivariable analysis, factors independently associated with severe hypoxemia in patients with obesity were intubation difficulty scale > 5 points and respiratory primary failure as reason for admission.ConclusionsPatients with obesity and acute hypoxemic respiratory failure had an increased risk of severe hypoxemia during intubation procedure as compared to patients without obesity. However, preoxygenation with noninvasive ventilation may not reduce this risk compared with high-flow nasal oxygen.Trial registration Clinical trial number: NCT02668458 (http://www.clinicaltrials.gov)

See DOI: 10.1111/resp.13050

Introduction: The clinical outcome of acute respiratory failure (ARF) treated with high flow nasal cannula (HFNC) may be favorable, but sometimes ARF deteriorates and requires invasive mechanical ventilation (IMV). However, little is known about the factors affecting this difference. Objective: The aim of this study is to investigate the predicting factors for HFNC failure in patients with ARF treated with HFNC. Methods: A cohort of consecutive patients with ARF treated with HFNC was studied. HFNC failure was defined as requiring IMV or death following HFNC. Results: 212 patients were enrolled, of whom 136 (64.2%) required IMV or died (HFNC failure). In univariate analysis, the significant factors associated with HFNC outcome were PaCO2, PaO2, PaO2/FiO2 (P/F) ratio, platelet count, serum C-reactive protein level, APACHE II score, P/F ratio difference (difference of P/F ratio before and after HFNC), and lung infiltration extent (P Conclusions: We demonstrated that APACHE II score over 16.5 and degree of oxygenation improvement (P/F ratio difference below 41.72) were independent predicting factors for HFNC failure. This suggests their role as evaluate criteria in setting indication for early IMV in patients with ARF being treated with HFNC. A larger, prospective study is required to confirm these findings.

BackgroundFew data exist on high flow nasal cannula (HFNC) use in patients with acute respiratory failure (ARF) admitted to general wards.Rationale and objectivesTo retrospectively evaluate feasibility and safety of HFNC in general wards under the intensivist-supervision and after specific training.MethodsPatients with ARF (dyspnea, respiratory rate-RR > 25/min, 150 < PaO2/FiO2 < 300 mmHg during oxygen therapy) admitted to nine wards of an academic hospital were included. Gas-exchange, RR, and comfort were assessed before HFNC and after 2 and 24 h of application.Results150 patients (81 male, age 74 [60–80] years, SOFA 4 [2–4]), 123 with de-novo ARF underwent HFNC with flow 60 L/min [50–60], FiO2 50% [36–50] and temperature 34 °C [31–37]. HFNC was applied a total of 1399 days, with a median duration of 7 [3–11] days. No major adverse events or deaths were reported. HFNC did not affect gas exchange but reduced RR (25–22/min at 2–24 h, p < 0.001), and improved Dyspnea Borg Scale (3–1, p < 0.001) and comfort (3–4, p < 0.001) after 24 h. HFNC failed in 20 patients (19.2%): 3 (2.9%) for intolerance, 14 (13.4%) escalated to NIV/CPAP in the ward, 3 (2.9%) transferred to ICU. Among these, one continued HFNC, while the other 2 were intubated and they both died. Predictors of HFNC failure were higher Charlson’s Comorbidity Index (OR 1.29 [1.07–1.55]; p = 0.004), higher APACHE II Score (OR 1.59 [1.09–4.17]; p = 0.003), and cardiac failure as cause of ARF (OR 5.26 [1.36–20.46]; p = 0.02).ConclusionIn patients with mild-moderate ARF admitted to general wards, the use of HFNC after an initial training and daily supervision by intensivists was feasible and seemed safe. HFNC was effective in improving comfort, dyspnea, and respiratory rate without effects on gas exchanges.Trial registration This is a single-centre, noninterventional, retrospective analysis of clinical data.

398EMF Mode of Respiratory Support and Mortality in Patients With Acute Hypoxemic Respiratory Failure from COVID-19

Background Acute respiratory failure (ARF) in immunocompromised patients is associated with increased incidence of mortality when endotracheal intubation is used. Early use of high flow nasal cannula (HFNC) or non-invasive ventilation (NIV) may prevent intubation. This prospective randomized controlled study was designed to evaluate the use of HFNC versus NIV in prevention of intubation in immunocompromised patients suffering from ARF. Methods After ethical committee’s approval and written informed consent, 76 patients were enrolled in the study, 38 in each group. Patients were randomized into High Flow Nasal Cannula (HFNC) group as they connected to HFNC to keep SpO2 92% or more alternating with simple face mask 10–15 L/min, or non-invasive ventilation (NIV) group as they connected to ICU ventilator pressure support 8 cmH2O and PEEP 5 cmH2O or more to keep SpO2 92% or more alternating with simple face mask 10–15 L/min. Tolerance to HFNC or NIV, need for intubation, ICU stay, hospital stay and 28-day mortality rate were documented and compared between the two groups. Results Seventy six patients were enrolled, 38 in each group, VAS tolerance was statistically significant higher in HFNC than NIV group 7(6–7) vs 6(5–7), respectively, p value < 0.001. Incidence of intubation was statistically significant lower in HFNC than NIV (31.6% vs 55.3%), respectively, (p value 0.037), however both groups had similar 28-day mortality rate, (p value 0.195). Conclusion Use of high flow nasal cannula in immunocompromised patients suffering from ARF has less incidence of endotracheal intubation but same 28-day mortality rate when compared to non-invasive ventilation.

Background:High-flow nasal cannula therapy has been shown to be useful in the treatment of patients with acute respiratory failure caused by severe acute respiratory syndrome-coronavirus disease-2. The ROX index can help predict the success of high-flow nasal cannula in coronavirus disease-19-related acute respiratory failure. However, the timing of ROX- index assessment is still unclear to protect the patients from complications due to early or delayed intubation.Aims:To evaluate the relation between ROX index patterns within the first 48 hours of the therapy and high-flow nasal cannula success rates. The secondary aim was to determine other possible predictors of high-flow nasal cannula failure.Study design:A cross-sectional study.Methods:Patients admitted to the intensive care unit between April 2020 and January 2022 with coronavirus disease-19-related acute respiratory failure and treated with high-flow nasal cannula were included in the study. Patients’ demographics, clinical characteristics and laboratory findings at intensive care unit admission; ROX indices at initiation, 2nd, 8th, 12th, 24th and 48th hours of high-flow nasal cannula; and outcomes were recorded.Results:In the study period, 69th patients were managed with high-flow nasal cannula for at least 2 hours. While 24 patients (34.7%) were successfully weaned from high-flow nasal cannula, 45 (65.3%) patients failed. Overall mortality at day 28 was 44.9%. ROX indices were lower in the high-flow nasal cannula failure group through the 12th, 24th, and 48th hours of the therapy, no significant change was observed (P = 0.33). While an overall increase in ROX index patterns were detected in patients weaned from high-flow nasal cannula (P = 0.002). Pairwise analyses revealed that ROX indexes remain stable during the first 8th hours in both groups, then improved to 12th hours of the therapy in successfully high-flow nasal cannula-weaned patients.Conclusion:Dynamic assessments of the ROX indexes could be more suggestive rather than a point assessment to identify patients who would benefit from the high-flow nasal cannula or deteriorate in coronavirus disease-19 related acute respiratory failure.

Effect of non-invasive oxygenation strategies in immunocompromised patients with severe acute respiratory failure: a post-hoc analysis of a randomised trial

Non-invasive respiratory support strategies in COVID-19

Noninvasive ventilation (NIV) is the recommended ventilatory support for acute cardiogenic pulmonary edema (CPE) associated with acute respiratory failure or hypercapnia. High-flow nasal cannula (HFNC) has emerged as an alternative to NIV in acute hypoxemic respiratory failure. We aimed to assess the efficacy of HFNC on early changes in [Formula: see text] and respiratory parameters in patients in the emergency department with acute hypercapnic CPE and to compare it to NIV. We conducted a prospective observational study in consecutive emergency department patients with acute hypercapnic CPE. Subjects received either HFNC or NIV, according to the attending emergency physician's expertise in HFNC. The primary outcome was change in [Formula: see text] after treatment for 1 h. Secondary outcomes were change in pH, breathing frequency, signs of work of breathing, and comparisons to NIV. Twenty-seven subjects with a discharge diagnosis of hypercapnic CPE were analyzed. Subjects had a median age of 87 y (interquartile range [IQR] 78-93); 37% were male. Twelve (44%) received HFNC, and 15 (56%) received NIV. Median of changes in [Formula: see text] from baseline to after 1 h of treatment were 7 mm Hg (IQR 4-11, P = .002) for HFNC and 3 mm Hg (IQR 1-8, P = .02) for NIV, with no between-group difference. pH, breathing frequency and signs of work of breathing also improved after both HFNC and NIV. This preliminary study suggests that HFNC treatment for 1 h improves [Formula: see text] and respiratory parameters in subjects with hypercapnic acute CPE in a manner that is comparable to NIV. Further studies are needed to assess HFNC as a possible alternative to NIV in early management of acute hypercapnic respiratory failure of cardiogenic origin. (ClinicalTrials.gov registration NCT03883555.).