High flow nasal cannula oxygen therapy versus non-invasive ventilation for acute exacerbations of chronic obstructive pulmonary disease with acute-moderate hypercapnic respiratory failure: a randomized controlled non-inferiority trial.

BACKGROUND: Although cumulative studies have demonstrated a beneficial effect of high-flow nasal cannula oxygen (HFNC) in acute hypercapnic respiratory failure, randomized trials to compare HFNC with non-invasive ventilation (NIV) as initial treatment in acute exacerbations of chronic obstructive pulmonary disease (AECOPD) patients with acute-moderate hypercapnic respiratory failure are limited. The aim of this randomized, open label, non-inferiority trial was to compare treatment failure rates between HFNC and NIV in such patients. METHODS: Patients diagnosed with AECOPD with a baseline arterial blood gas pH between 7.25 and 7.35 and PaCO2 ≥ 50 mmHg admitted to two intensive care units (ICUs) at a large tertiary academic teaching hospital between March 2018 and December 2022 were randomly assigned to HFNC or NIV. The primary endpoint was the rate of treatment failure, defined as endotracheal intubation or a switch to the other study treatment modality. Secondary endpoints were rates of intubation or treatment change, blood gas values, vital signs at one, 12, and 48 h, 28-day mortality, as well as ICU and hospital lengths of stay. RESULTS: 225 total patients (113 in the HFNC group and 112 in the NIV group) were included in the intention-to-treat analysis. The failure rate of the HFNC group was 25.7%, while the NIV group was 14.3%. The failure rate risk difference between the two groups was 11.38% (95% CI 0.25-21.20, P = 0.033), which was higher than the non-inferiority cut-off of 9%. In the per-protocol analysis, treatment failure occurred in 28 of 110 patients (25.5%) in the HFNC group and 15 of 109 patients (13.8%) in the NIV group (risk difference, 11.69%; 95% CI 0.48-22.60). The intubation rate in the HFNC group was higher than in the NIV group (14.2% vs 5.4%, P = 0.026). The treatment switch rate, ICU and hospital length of stay or 28-day mortality in the HFNC group were not statistically different from the NIV group (all P > 0.05). CONCLUSION: HFNC was not shown to be non-inferior to NIV and resulted in a higher incidence of treatment failure than NIV when used as the initial respiratory support for AECOPD patients with acute-moderate hypercapnic respiratory failure. TRIAL REGISTRATION: chictr.org (ChiCTR1800014553). Registered 21 January 2018, http://www.chictr.org.cn.

Continuous positive airway pressure versus high-flow nasal cannula oxygen therapy for acute hypoxemic respiratory failure: A randomized controlled trial.

BACKGROUND AND OBJECTIVE: The relative effectiveness of initial non-invasive respiratory strategies for acute respiratory failure using continuous positive airway pressure (CPAP) or high-flow nasal cannula (HFNC) is unclear. METHODS: We conducted a multicenter, open-label, parallel-group randomized controlled trial to compare the efficacy of CPAP and HFNC on reducing the risk of meeting the prespecified criteria for intubation and improving clinical outcomes of acute hypoxemic respiratory failure. The primary endpoint was the time taken to meet the prespecified criteria for intubation within 28 days. RESULTS: Eighty-five patients were randomly assigned to the CPAP or HFNC group. Eleven (28.9%) in the CPAP group and twenty (42.6%) in the HFNC group met the criteria for intubation within 28 days. Compared with HFNC, CPAP reduced the risk of meeting the intubation criteria (hazard ratio [HR], 0.327; 95% CI, 0.148-0.724; p = 0.006). There were no significant between-group differences in the intubation rates, in-hospital and 28-day mortality rates, ventilator-free days, duration of the need for respiratory support, or duration of hospitalization for respiratory illness. Pulmonary oxygenation was significantly better in the CPAP group, with significantly lower pH and higher partial pressure of carbon dioxide, but there were no differences in the respiratory rate between groups. CPAP and HFNC were associated with few possibly causal adverse events. CONCLUSION: CPAP is more effective than HFNC at reducing the risk of meeting the intubation criteria in patients with acute hypoxemic respiratory failure.

Oxygen concentration titration guided by oxygen reserve index during pediatric laryngeal surgery with high-flow nasal cannula oxygen: a randomized controlled trial.

PURPOSE: The objective of this study was to evaluate whether adjusting the oxygen concentration guided by the Oxygen Reserve Index (ORI) during pediatric laryngeal surgery with High Flow Nasal Cannula Oxygen (HFNO) could achieve postoperative PaO2 close to physiological levels while ensuring adequate oxygenation in surgery. METHODS: Sixty pediatric patients undergoing laryngeal surgery or examination were randomly assigned to two groups. The ORI group received oxygen concentration adjustments every 5 min to maintain a target ORI value of 0.21, whereas the control group did not undergo any adjustments. Postoperative PaO2, time weighted average fraction of inspired oxygen (FiO2), and mean Peripheral Oxygen Saturation (SpO2) were compared between groups. Finally, some analyses were conducted to examine the relationship of ORI with PaO2. RESULTS: In general, the postoperative PaO2 was 164.9 ± 48.8 mmHg in ORI group and 323.0 ± 87.7 mmHg in control group (P < 0.01). The time weighted average FiO2 in the ORI group was 85.9 [81.8-92.7] %. There was no significant difference in mean SpO2 between the two groups (ORI vs. control: 98.4 [97.7-99.2] vs. 98.8 [97.7-99.5]; P = 0.36). According to the analyses, the optimal cut value for ORI was determined to be 0.195 when PaO2 was 150 mmHg. CONCLUSIONS: In pediatric laryngeal surgery with HFNO, reducing oxygen concentration guided by ORI helped achieve postoperative PaO2 levels closer to physiological norms without compromising intra-operative oxygenation.

Effects of high flow nasal cannula following minimally invasive esophagectomy in ICU patients: A prospective pre-post study.

BACKGROUND/PURPOSE: Patients with esophageal cancer who undergo minimally invasive esophagectomy are at risk of postoperative pulmonary complications. High-flow nasal cannula oxygen therapy delivers humidified, warmed positive airway pressure but has not been applied routinely after surgery. Here, we aimed to compare high-flow nasal cannula and conventional oxygen therapy in patients with esophageal cancer during intensive care unit hospitalization 48 h postoperatively. METHODS: In this prospective pre- and post-intervention study, patients with esophageal cancer who underwent elective minimally invasive esophagectomy (MIE) and were extubated in the operation room and admitted to the intensive care unit postoperatively were assigned to receive either high-flow nasal cannula (HFNCO) or standard oxygen (SO) therapy. Participants in the SO group were recruited before January 2020, and those in the HFNCO group were enrolled after January 2020. The primary outcome was the difference in postoperative pulmonary complication incidence. Secondary outcomes were the occurrence of desaturation within 48 h, PaO2/FiO2 within 48 h, anastomotic leakage, length of intensive care unit and hospital stay, and mortality. RESULTS: The standard oxygen and high-flow nasal cannula oxygen groups comprised 33 and 36 patients, respectively. Baseline characteristics were comparable between groups. In the HFNCO group, postoperative pulmonary complication incidence was significantly reduced (22.2% vs 45.5%) and PaO2/FiO2 was significantly increased. No other between-group differences were observed. CONCLUSION: HFNCO therapy significantly reduced postoperative pulmonary complication incidence after elective MIE in patients with esophageal cancer without increasing the risk of anastomotic leakage.

Use of high-flow nasal cannula oxygen and risk factors for high-flow nasal cannula oxygen failure in critically-ill patients with COVID-19.

BACKGROUND: High-flow nasal oxygen therapy (HFNC) may be an attractive first-line ventilatory support in COVID-19 patients. However, HNFC use for the management of COVID-19 patients and risk factors for HFNC failure remain to be determined. METHODS: In this retrospective study, we included all consecutive COVID-19 patients admitted to our intensive care unit (ICU) in the first (Mars-May 2020) and second (August 2020- February 202) French pandemic waves. Patients with limitations for intubation were excluded. HFNC failure was defined as the need for intubation after ICU admission. The impact of HFNC use was analyzed in the whole cohort and after constructing a propensity score. Risk factors for HNFC failure were identified through a landmark time-dependent cause-specific Cox model. The ability of the 6-h ROX index to detect HFNC failure was assessed by generating receiver operating characteristic (ROC) curve. RESULTS: 200 patients were included: HFNC was used in 114(57%) patients, non-invasive ventilation in 25(12%) patients and 145(72%) patients were intubated with a median delay of 0 (0-2) days after ICU admission. Overall, 78(68%) patients had HFNC failure. Patients with HFNC failure had a higher ICU mortality rate (34 vs. 11%, p = 0.02) than those without. At landmark time of 48 and 72 h, SAPS-2 score, extent of CT-Scan abnormalities > 75% and HFNC duration (cause specific hazard ratio (CSH) = 0.11, 95% CI (0.04-0.28), per + 1 day, p < 0.001 at 48 h and CSH = 0.06, 95% CI (0.02-0.23), per + 1 day, p < 0.001 at 72 h) were associated with HFNC failure. The 6-h ROX index was lower in patients with HFNC failure but could not reliably predicted HFNC failure with an area under ROC curve of 0.65 (95% CI(0.52-0.78), p = 0.02). In the matched cohort, HFNC use was associated with a lower risk of intubation (CSH = 0.32, 95% CI (0.19-0.57), p < 0.001). CONCLUSIONS: In critically-ill COVID-19 patients, while HFNC use as first-line ventilatory support was associated with a lower risk of intubation, more than half of patients had HFNC failure. Risk factors for HFNC failure were SAPS-2 score and extent of CT-Scan abnormalities > 75%. The risk of HFNC failure could not be predicted by the 6-h ROX index but decreased after a 48-h HFNC duration.

Association between respiratory rate oxygenation index and need for positive pressure ventilation in children on high flow nasal cannula for bronchiolitis.

Our objective was to evaluate the association of respiratory rate oxygenation index (ROX) with the need for positive pressure ventilation in children < 2 years of age with bronchiolitis on high flow nasal cannula (HFNC) therapy. We performed a single-center prospective observational study of a convenience sample of children < 2 years of age with bronchiolitis who had HFNC initiated in the pediatric emergency department between November and March, 2018-2020. ROX was calculated as pulse oximetry/FiO2/respiratory rate at HFNC initiation. Demographics, need for positive pressure ventilation (PPV), disposition, and hospital length of stay were collected. Logistic regression model was used to determine the odds ratio for PPV need relative to the highest ROX quartile. Of the 373 patients included, 49 (13.1%) required PPV. ROX was lower in patients who required PPV compared with those who did not (5.86 [4.71-7.42] vs. 6.74 [5.46-8.25]; p = 0.01). Logistic regression revealed that those patients whose ROX was in the lowest quartile (< 5.39) were three times more likely to require PPV compared to those in the highest quartile (> 8.21). These results held true after adjusting for confounders (odds ratio 3.1; 95% CI [1.3 to 7.5]; p = 0.02). The model's AUROC (0.701) indicated acceptable discrimination between cases and controls. CONCLUSION: Low ROX index was associated with the need for PPV in children with bronchiolitis on HFNC. The risk stratification provided and ROX threshold for risk stratification require confirmation in other populations with a larger sample size. WHAT IS KNOWN: • Demographic and clinical factors associated with high flow nasal cannula (HFNC) therapy in children with bronchiolitis has been studied. WHAT IS NEW: • This is the first study to  report the utility of association of Respiratory Rate Oxygenation (ROX) index for need for positive pressure ventilation (PPV) in children < 2 years of age with bronchiolitis on HFNC therapy. • ROX was lower in children who required PPV and children whose ROX was in the lowest quartile (< 5.39) were three times more likely to require PPV compared to those in the highest quartile (> 8.21).

Effect of high-flow nasal cannula oxygen therapy on exercise tolerance in patients with idiopathic pulmonary fibrosis: A randomized crossover trial.

BACKGROUND AND OBJECTIVE: Exercise capacity in idiopathic pulmonary fibrosis (IPF) is limited by exercise-induced hypoxaemia. This study aimed to examine the effect of high-flow nasal cannula oxygen therapy (HFNC) on exercise tolerance in patients with IPF. METHODS: We conducted a single-centre, open-label, randomized crossover trial to compare HFNC and Venturi mask (VM) therapy in terms of exercise tolerance. Patients underwent constant-load symptom-limited exercise testing at 80% peak work rate with HFNC or a VM in a randomized order. The settings were 60 L/min and a 50% fraction of inspired oxygen (FiO2 ) for HFNC and 12 L/min and 50% FiO2 for VM. The primary outcome was endurance time, and the secondary outcomes were heart rate (HR), percutaneous oxygen saturation (SpO2 ), dyspnoea and leg fatigue, as determined by the modified Borg Scale at the isotime and endpoint, and the level of comfort while using the devices. RESULTS: Twenty-four participants (75.0% men; age, median [interquartile range]: 77.5 [68.8-83.0] years) were enrolled. Compared with VM, HFNC significantly improved the endurance time (647.5 s [454.0-1014.8] vs. 577.5 s [338.0-861.5]), minimum SpO2 (96.0% [95.0-98.0] vs. 94.0% [92.8-96.0]) and leg fatigue at the isotime (3.0 [1.6-4.0] vs. 5.0 [3.0-6.3]) and endpoint (4.0 [2.8-5.0] vs. 5.0 [3.8-6.3]). Differences in maximum HR, dyspnoea at the isotime and endpoint and comfort were non-significant between HFNC and VM therapy. CONCLUSION: HFNC increased exercise tolerance in patients with stable IPF experiencing exercise-induced hypoxaemia.

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%, pheterogeneity  = .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%, pheterogeneity   = .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%, pheterogeneity  = .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%, pheterogeneity  = .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%, pheterogeneity   = .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%, pheterogeneity  = .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.

[High-flow nasal cannula oxygen therapy in prostate-targeted needle biopsy in high-risk patients with obstructive sleep apnea syndrome].

OBJECTIVE: To compare the effect of high-flow nasal cannula oxygen therapy (HFNC) from that of conventional nasal cannula oxygen therapy (CNC) on oxygenation during prostate-targeted needle biopsy under total intravenous anesthesia in high-risk patients with obstructive sleep apnea syndrome (OSAS). METHODS: We randomly assigned 64 high-risk OSAS patients to two groups of an equal number to receive HFNC and CNC, respectively, under total intravenous anesthesia. We recorded the incidence rates of SpO2<95% and the lowest SpO2 during surgery, the mean arterial pressure (MAP), heart rate (HR) and oxygen saturation (SpO2) upon entering the operation room (T0), at the beginning (T1) and the end of surgery (T2) and at 30 minutes postoperatively (T3), as well as arterial partial pressure of oxygen (PaO2) and arterial partial pressure of carbon dioxide (PaCO2) at T0 and T2, and the incidence rates of airway intervention and adverse events, followed by comparison of the parameters between the two groups. RESULTS: Both the lowest SpO2 and PaO2 were significantly increased in the HFNC group compared with those in the CNC group (P < 0.05) while no statistically significant difference was observed in PaCO2 between the two groups (P > 0.05). The intraoperative incidence rates of hypoxia, airway intervention, choking and body movement were remarkably lower in the HFNC than in the CNC group (P < 0.05), but there were no statistically significant differences in the operation time, anesthesia duration and propofol dosage between the two groups (P > 0.05). CONCLUSION: HFNC may provide more adequate oxygenation, improve airway management, and reduce the incidence of hypoxemia in high-risk OSAS patients during prostate biopsy under total intravenous anesthesia.

Effectiveness of high flow nasal cannula oxygen therapy in patients of acute pulmonary thromboembolism with acute hypoxemic respiratory failure.

Background: Acute Pulmonary thromboembolism (PTE) is associated with acute hypoxemic respiratory failure (AHRF), which is a leading cause of death in these patients. High-Flow Nasal Cannula (HFNC) oxygen therapy is a cornerstone of the treatment of respiratory failure. The aim of the present study is to explore the efficacy of HFNC in the treatment of patients of acute PTE with acute hypoxemic respiratory failure in India. Methods: This is a retrospective study of patients admitted to a tertiary care center with acute PTE with AHRF during the period from January 2018 to January 2020. After reviewing medical files, patients of acute PTE with AHRF treated with HFNC were included in the study. We analyzed the improvement in oxygenation parameters and respiratory rate, as well as outcome in these patients. Results: During the above specified period, 12 patients suffering from PTE with AHRF were treated with HFNC. After 1 h of the initiation of HFNC along with anticoagulation, the respiratory parameters of patients significantly improved. HFNC was applied for a period of 6-10 days. None of the patients required intubation for AHRF, and all patients were discharged from the hospital on oral anticoagulants. Conclusion: HFNC oxygen therapy in patients with acute PTE with AHRF showed rapid improvement of oxygenation and respiratory rate. HFNC oxygen therapy is an efficacious treatment for patients with AHRF secondary to acute PTE without any significant hemodynamic effect. It acts as a superior modality of oxygen therapy avoiding noninvasive and invasive ventilatory support.

[Comparison of high-flow nasal cannula oxygen therapy and non-rebreather face mask in the treatment of mild carbon monoxide poisoning].

Objective: To compare the efficacy of high-flow nasal cannula oxygen therapy (HFNC) and non-rebreather face mask (NRFM) in the treatment of mild acute carbon monoxide poisoning (ACOP) in reducing carboxyhemoglobin (COHb) , and to explore the feasibility of HFNC in the treatment of ACOP. Methods: Patients with mild ACOP with COHb >10% who were admitted to the emergency department of Northern Jiangsu People's Hospital from January 2015 to December 2020 were analyzed, and those with altered consciousness, mechanical ventilation and those requiring hyperbaric oxygen therapy were excluded. The patients were divided into HFNC group and NRFM group according to the oxygen therapy used in the emergency department. The COHb decline value and COHb half-life in the two groups were observed. Results: Seventy-one patients were enrolled, including 39 in the NRFM group and 32 in the HFNC group. The baseline COHb in the HFNC group was 24.8%±8.3%, and that in the NRFM group was 22.5%±7.1%, with no significant difference between the two groups (t=1.27, P=0.094) . At 60 min, 90 min and 120 min of treatment, COHb in both groups decreased, but the COHb in HFNC group was lower than that in NRFM group at the same time point (P<0.05) . After 1 h of treatment, the COHb decrease in the HFNC group (16.9%±4.5%) was significantly higher than that in the NRFM group (10.1%±7.8%) (t=4.32, P=0.013) . The mean half-life of COHb in the HFNC group (39.3 min) was significantly lower than that in the NRFM group (61.4 min) (t=4.69, P=0.034) . Conclusion: HFNC treatment of mild ACOP can rapidly reduce blood COHb level, it is a potential oxygen therapy method for clinical treatment of ACOP.

Modified high-flow nasal cannula oxygen therapy versus conventional oxygen therapy in patients undergoing bronchoscopy: a randomized clinical trial.

BACKGROUND: Hypoxemia frequently occurs during bronchoscopy. High-flow nasal cannula (HFNC) oxygen therapy may be a feasible alternative to prevent the deterioration of gas exchange during bronchoscopy. With the convenience of clinical use in mind, we modified an HFNC using a single cannula. This clinical trial was designed to test the hypothesis that a modified HFNC would decrease the proportion of patients with a single moment of peripheral arterial oxygen saturation (SpO2) < 90% during bronchoscopy. METHODS: In this single-center, prospective randomized controlled trial, hospitalized patients in the respiratory department in need of diagnostic bronchoscopy were randomly assigned to a modified HFNC oxygen therapy group or a conventional oxygen therapy (COT) group. The primary outcome was the proportion of patients with a single moment of SpO2 < 90% during bronchoscopy. RESULTS: Eight hundred and twelve patients were randomized to the modified HFNC (n = 406) or COT (n = 406) group. Twenty-four patients were unable to cooperate or comply with bronchoscopy. Thus, 788 patients were included in the analysis. The proportion of patients with a single moment of SpO2 < 90% during bronchoscopy in the modified HFNC group was significantly lower than that in the COT group (12.5% vs. 28.8%, p < 0.001). There were no significant differences in the fraction of inspired oxygen between the two groups. The lowest SpO2 during bronchoscopy and 5 min after bronchoscopy in the modified HFNC group was significantly higher than that in the COT group. Multivariate analysis showed that a baseline forced vital capacity (FVC) < 2.7 L (OR, 0.276; 95% CI, 0.083-0.919, p = 0.036) and a volume of fluid instilled > 60 ml (OR, 1.034; 95% CI, 1.002-1.067, p = 0.036) were independent risk factors for hypoxemia during bronchoscopy in the modified HFNC group. CONCLUSIONS: A modified HFNC could decrease the proportion of patients with a single moment of SpO2 < 90% during bronchoscopy. A lower baseline FVC and large-volume bronchoalveolar lavage may predict desaturation during bronchoscopy when using a modified HFNC. Trial registration ClinicalTrials. Gov: NCT02606188. Registered 17 November 2015.

High-flow nasal cannula oxygen therapy: Alternative respiratory therapy for severe post-transplant hypoxemia in children with hepatopulmonary syndrome.

Severe post-transplant hypoxemia, which is defined as <50 mm Hg of the partial pressure of oxygen in arterial blood/fraction of inspired oxygen (P/F) ratio, is a major post-operative complication with high mortality rates in patients with hepatopulmonary syndrome (HPS). Non-invasive positive pressure ventilation therapy and mechanical ventilation are options for respiratory support of patients with severe post-transplant hypoxemia. However, these therapies are associated with several problems, such as compliance, ventilator-associated pneumonia, and lung injury. We here firstly described two children with HPS who developed severe post-transplant hypoxemia (lowest post-operative P/F ratio, 49.7 and 34.0 mm Hg, respectively) that was successfully managed with high-flow nasal cannula (HFNC) oxygen therapy and vasodilation drugs without adverse complications or necessity of reintubation. We consider that HFNC oxygen therapy could become a safe alternative respiratory therapy or be added to the other such as inhaled nitric oxide (iNO), methylene blue (MB), inhaled epoprostenol, embolization of abnormal pulmonary vessels, and combination of iNO and MB for severe post-transplant hypoxemia in children with HPS.

Application of high-flow nasal cannula in hypoxemic patients with COVID-19: a retrospective cohort study.

BACKGROUND: It had been shown that High-flow nasal cannula (HFNC) is an effective initial support strategy for patients with acute respiratory failure. However, the efficacy of HFNC for patients with COVID-19 has not been established. This study was performed to assess the efficacy of HFNC for patients with COVID-19 and describe early predictors of HFNC treatment success in order to develop a prediction tool that accurately identifies the need for upgrade respiratory support therapy. METHODS: We retrospectively reviewed the medical records of patients with COVID-19 treated by HFNC in respiratory wards of 2 hospitals in Wuhan between 1 January and 1 March 2020. Overall clinical outcomes, the success rate of HFNC strategy and related respiratory variables were evaluated. RESULTS: A total of 105 patients were analyzed. Of these, 65 patients (61.9%) showed improved oxygenation and were successfully withdrawn from HFNC. The PaO2/FiO2 ratio, SpO2/FiO2 ratio and ROX index (SpO2/FiO2*RR) at 6h, 12h and 24h of HFNC initiation were closely related to the prognosis. The ROX index after 6h of HFNC initiation (AUROC, 0.798) had good predictive capacity for outcomes of HFNC. In the multivariate logistic regression analysis, young age, gender of female, and lower SOFA score all have predictive value, while a ROX index greater than 5.55 at 6 h after initiation was significantly associated with HFNC success (OR, 17.821; 95% CI, 3.741-84.903 p<0.001). CONCLUSIONS: Our study indicated that HFNC was an effective way of respiratory support in the treatment of COVID-19 patients. The ROX index after 6h after initiating HFNC had good predictive capacity for HFNC outcomes.

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

BACKGROUND: Acute respiratory failure (ARF) is a common cause of emergency department (ED) and intensive care unit (ICU) admissions. High-flow nasal cannula oxygen therapy (HFNC) is widely used for patients with ARF. OBJECTIVE: Our aim was to evaluate the latest evidence regarding the application of HFNC in immunocompromised patients with ARF. METHODS: We searched PubMed, Embase, and Cochrane databases from inception to January 2019. The primary outcome was short-term mortality and the secondary outcomes were intubation rate and length of ICU stay. RESULTS: Eight studies involving 2,179 immunocompromised subjects with ARF were included. No significant differences for short-term mortality were observed when comparing HFNC with conventional oxygen therapy (COT) (risk ratio [RR] 0.89; 95% confidence interval [CI] 0.73 to 1.09; p = 0.25, I2 = 47%) and with noninvasive ventilation (NIV) (RR 0.66; 95% CI 0.37 to 1.18; p = 0.16, I2 = 58%). Lower intubation rates were found when comparing HFNC with COT (RR 0.89; 95% CI 0.80 to 0.99; p = 0.03, I2 = 0%) and no significant difference was found between HFNC and NIV (RR 0.74; 95% CI 0.46 to 1.19; p = 0.22, I2 = 67%). The length of ICU stay was similar when comparing HFNC with COT (mean difference [MD] 0.59; 95% CI -1.68 to 2.85; p = 0.61, I2 = 56%), but was significantly shorter when HFNC was compared with NIV (MD -2.13; 95% CI -3.98 to -0.29; p = 0.02, I2 = 0%). CONCLUSIONS: There was no significant difference in short-term mortality with use of HFNC when compared with COT or NIV for immunocompromised patients with ARF. A lower intubation rate than COT and a shorter length of ICU stay than NIV were observed in the HFNC group.

[Application value of non-invasive ventilation combined with high flow nasal cannula oxygen therapy in sequential treatment of patients with chronic obstructive pulmonary disease after mechanical ventilation].

Objective: To investigate the value of non-invasive ventilation (NIV) combined with high flow nasal cannula oxygen therapy (HFNCO) in sequential treatment of patients with chronic obstructive pulmonary disease after mechanical ventilation. Methods: Chronic obstructive pulmonary disease with acute exacerbation (AECOPD) patients with invasive mechanical ventilation (MV) and successful withdrawal admitted into Huxi Affiliated Hospital of Jining Medical College from January 2018 to December 2019 were enrolled for perspective study. The patients were divided into treatment group (n=40) and control group (n=33) by random number table method. The treatment group was given NIV and HFNCO, the control group was given NIV treatment alone. Bedside ultrasound was used to measure the patients' diaphragmatic motion, and the differences between the two groups of patients before treatment, 24, 48 and 72 h after treatment were compared in diaphragmatic excursions during quiet breathing (DEq), diaphragmatic excursions during deep breathing(DEd), diaphragmatic shallow fast breathing index (D-RSBI), arterial oxygen partial pressure (PaO(2)), arterial partial pressure of carbon dioxide (PaCO(2)), re-tracheal intubation rate, mortality rate for 28 days and average duration of NPPV treatment within 3 days. Results: There were no statistically significant differences in DEq, DEd, D-RSBI, PaO(2) and PaCO(2) between the two groups before treatment (all P>0.05). After 24 h treatment, DEd decreased in both groups, D-RSBI increased in both groups, However, D-RSBI [(1.33±0.56) vs (1.62±0.59) times·min(-1)·mm(-1)] in the treatment group was significantly lower than the control group, P=0.034. After 72 h treatment, DEd [(41.4±8.1) vs (37.8±6.0) mm] was significantly higher than the control group, D-RSBI [(1.02±0.27) vs (1.22±0.43) times·min(-1)·mm(-1)] was significantly lower than the control group (all P<0.05). The average duration of NIV treatment time [(7.5±1.2) vs (9.3±2.6) h] in the treatment group was significantly shorter than that in the control group (P<0.01). There were no statistically significant differences in PaO(2), PCO(2), re-tracheal intubation rate and the mortality rate of 28 days. Conclusion: NIV combined with HFNCO sequential therapy can effectively relieve diaphragm fatigue and promote recovery of respiratory muscle strength, and it's better than NIV alone.

Role of Noninvasive Oxygen Therapy Strategies in COVID-19 Patients: Where are We Going?

How to cite this article: Dixit SB. Role of Noninvasive Oxygen Therapy Strategies in COVID-19 Patients: Where are We Going? Indian J Crit Care Med 2020;24(10):897-898.

Noninvasive Oxygen Strategies to Manage Confirmed COVID-19 Patients in Indian Intensive Care Units: A Survey.

BACKGROUND: About 5% of hospitalized coronavirus disease 2019 (COVID-19) patients will need intensive care unit (ICU) admission for hypoxemic respiratory failure requiring oxygen support. The choice between early mechanical ventilation and noninvasive oxygen therapies, such as, high-flow nasal oxygen (HFNO) and/or noninvasive positive-pressure ventilation (NPPV) has to balance the contradictory priorities of protecting healthcare workers by minimizing aerosol-generation and optimizing resource management. This survey over two timeframes aimed to explore the controversial issue of location and noninvasive oxygen therapy in non-intubated ICU patients using a clinical vignette. MATERIALS AND METHODS: An online survey was designed, piloted, and distributed electronically to Indian intensivists/anesthetists, from private hospitals, government hospitals, and medical college hospitals (the latter two referred to as first-responder hospitals), who are directly responsible for admitting/managing patients in ICU. RESULTS: Of the 204 responses (125/481 in phase 1 and 79/320 in phase 2), 183 responses were included. Respondents from first-responder hospitals were more willing to manage non-intubated hypoxemic patients in neutral pressure rooms, while respondents from private hospitals preferred negative-pressure rooms (p < 0.001). In both the phases, private hospital doctors were less comfortable to use any form of noninvasive oxygen therapies in neutral-pressure rooms compared to first-responder hospitals (low-flow oxygen therapy: 72 vs 50%, p < 0.01; HFNO: 47 vs 24%, p < 0.01 and NPPV: 38 vs 28%, p = 0.20). INTERPRETATION: Variations existed in practices among first-responder and private intensivists/anesthetists. The resource optimal private hospital intensivists/anesthetists were less comfortable using noninvasive oxygen therapies in managing COVID-19 patients. This may reflect differential resource availability necessitating resolution at national, state, and local levels. HOW TO CITE THIS ARTICLE: Subramaniam A, Haji JY, Kumar P, Ramanathan K, Rajamani A. Noninvasive Oxygen Strategies to Manage Confirmed COVID-19 Patients in Indian Intensive Care Units: A Survey. Indian J Crit Care Med 2020;24(10):926-931.

High-flow nasal cannula oxygen therapy decreases postextubation neuroventilatory drive and work of breathing in patients with chronic obstructive pulmonary disease.

BACKGROUND: The physiological effects of high-flow nasal cannula O2 therapy (HFNC) have been evaluated mainly in patients with hypoxemic respiratory failure. In this study, we compared the effects of HFNC and conventional low-flow O2 therapy on the neuroventilatory drive and work of breathing postextubation in patients with a background of chronic obstructive pulmonary disease (COPD) who had received mechanical ventilation for hypercapnic respiratory failure. METHODS: This was a single center, unblinded, cross-over study on 14 postextubation COPD patients who were recovering from an episode of acute hypercapnic respiratory failure of various etiologies. After extubation, each patient received two 1-h periods of HFNC (HFNC1 and HFNC2) alternated with 1 h of conventional low-flow O2 therapy via a face mask. The inspiratory fraction of oxygen was titrated to achieve an arterial O2 saturation target of 88-92%. Gas exchange, breathing pattern, neuroventilatory drive (electrical diaphragmatic activity (EAdi)) and work of breathing (inspiratory trans-diaphragmatic pressure-time product per minute (PTPDI/min)) were recorded. RESULTS: EAdi peak increased from a mean (±SD) of 15.4 ± 6.4 to 23.6 ± 10.5 µV switching from HFNC1 to conventional O2, and then returned to 15.2 ± 6.4 µV during HFNC2 (conventional O2: p < 0.05 versus HFNC1 and HFNC2). Similarly, the PTPDI/min increased from 135 ± 60 to 211 ± 70 cmH2O/s/min, and then decreased again during HFNC2 to 132 ± 56 (conventional O2: p < 0.05 versus HFNC1 and HFNC2). CONCLUSIONS: In patients with COPD, the application of HFNC postextubation significantly decreased the neuroventilatory drive and work of breathing compared with conventional O2 therapy.