High-flow nasal cannula in children with asthma exacerbation: A review of current evidence

Asthma is the commonest obstructive airway disease and the leading cause of morbidity in children. In the pediatric population, acute exacerbations of asthma are a frequent cause of presentations and hospital admissions. An acute asthma exacerbation is potentially life-threatening; it is predominantly treated using conventional oxygen therapy with bronchodilators and systemic corticosteroids. The treatment of those who do not respond to conventional therapy is escalated to noninvasive positive pressure ventilation (NIPPV) before invasive ventilation. Although NIPPV has demonstrated benefits and safety, it still has limitations such as treatment intolerance caused mainly by discomfort and complications. High-flow oxygen therapy administered through a nasal cannula (HFNC) provides respiratory support with adequate airway humidity and has demonstrated safety and benefits in clinical practice. In the present review, we discuss HFNC and variations in HFNC use, focusing on its feasibility and current evidence of using it on children with asthma exacerbations.

Nasal Continuous Positive Airway Pressure and High-Flow Nasal Cannula Today

This study reviews the mechanisms of action and physiologic effects of nasal continuous positive airway pressure (nCPAP) and high-flow nasal cannula (HFNC) in preterm infants with respiratory distress syndrome, discusses the main characteristics of available devices and patients' interfaces, reports on risk of failure and possible adverse effects, and summarizes clinical evidence regarding effectiveness for preventing mechanical ventilation as primary respiratory support or after extubation in the neonatal intensive care unit. nCPAP is preferred to HFNC as primary mode of noninvasive respiratory support in preterm infants with respiratory distress syndrome, whereas HFNC is an effective alternative to nCPAP after extubation.

Optimizing high-flow nasal cannula flow settings in adult hypoxemic patients based on peak inspiratory flow during tidal breathing

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 (F_IO₂) ≥ 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. F_IO₂ was titrated to maintain pulse oximetry (SpO₂) of 90–97%. SpO₂/F_IO₂, respiratory rate (RR), ROX index [(SpO₂/F_IO₂)/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 F_IO₂, 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 F_IO₂ at 0.62 (0.16) to obtain an SpO₂/F_IO₂ 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 F_IO₂ 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

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00949-8.

Impact of high-flow oxygen therapy during exercise in idiopathic pulmonary fibrosis: a pilot crossover clinical trial

BACKGROUND

Supplemental oxygen delivered with standard oxygen therapy (SOT) improves exercise capacity in patients with idiopathic pulmonary fibrosis (IPF). Although high-flow nasal cannula oxygen therapy (HFNC) improves oxygenation in other respiratory diseases, its impact on exercise performance has never been evaluated in IPF patients. We hypothesized that HFNC may improve exercise capacity in IPF subjects compared to SOT.

METHODS

This was a prospective, crossover, pilot randomized trial that compared both oxygenation methods during a constant submaximal cardiopulmonary exercise test (CPET) in IPF patients with exertional oxygen saturation (SpO₂) ≤ 85% in the 6-min walking test. The primary outcome was endurance time (Tlim). Secondary outcomes were muscle oxygen saturation (StO₂) and respiratory and leg symptoms.

RESULTS

Ten IPF patients [71.7 (6) years old, 90% males] were included. FVC and DL_CO were 58 ± 11% and 31 ± 13% pred. respectively. Tlim during CPET was significantly greater using HFNC compared to SOT [494 ± 173 vs. 381 ± 137 s, p = 0.01]. HFNC also associated with a higher increase in inspiratory capacity (IC) [19.4 ± 14.2 vs. 7.1 ± 8.9%, respectively; p = 0.04], and a similar trend was observed in StO₂ during exercise. No differences were found in respiratory or leg symptoms between the two oxygen devices.

CONCLUSIONS

This is the first study demonstrating that HFNC oxygen therapy improves exercise tolerance better than SOT in IPF patients with exertional desaturation. This might be explained by changes in ventilatory mechanics and muscle oxygenation. Further and larger studies are needed to confirm the benefits of HFNC in IPF patients and its potential usefulness in rehabilitation programs.

Repackaging of Malfunctioning High-flow Nasal Cannula as a Rescue Oxygen Therapy: An Innovation amid COVID-19 Crisis

Oxygen supplementation is required for approximately 14% of the patients diagnosed of having COVID-19 infection. Despite the use of conventional oxygen therapy, 5% among these require treatment in the intensive care unit (ICU). Here, we are describing a situation in which oxygen therapy was delivered to the patients by making an assembly of oxygen tubing, three-way stopcock, and high-flow nasal cannula (HFNC) present in the hospital setting following the malfunction of air blender of HFNC machine (Fig. 1). This assembly might be useful as rescue oxygen therapy during a malfunction of HFNC machine and in resource-limited settings where HFNC machine is not available. The mechanisms of action could be (1) washout of anatomic dead space due to medium oxygen flow, (2) improved gas mixing in large airways, and (3) increased oxygen concentration inside the conducting airway.

How to cite this article: Kumar A, Kumar A, Kumar N, Kumar A, Singh V, Kumar S, et al. Repackaging of Malfunctioning High-flow Nasal Cannula as a Rescue Oxygen Therapy: An Innovation amid COVID-19 Crisis. Indian J Crit Care Med 2021;25(8):948–949.

Clinical utility of the pediatric respiratory rate-oxygenation index

A recently published study evaluated the pediatric respiratory rate-oxygenation index to predict high-flow nasal cannula therapy failure in children. This commentary outlines limitations to the clinical applicability of the study results and suggestions for future research.

Current practices and policies regarding the use of high-flow nasal cannula on general pediatric inpatient wards in Canada

OBJECTIVES

High-flow nasal cannula (HFNC) oxygen therapy has become a common treatment for respiratory conditions in children. To our knowledge, no study has described practice patterns for HFNC on pediatric inpatient wards in Canada. The aim of this study was to survey current practices and policies regarding the use of HFNC on the ward in children's hospitals in Canada.

METHODS

We conducted a web-based survey of Pediatric Hospital Medicine section chiefs in major tertiary care hospitals in Canada. The primary outcome was the proportion of hospitals that use HFNC on the general pediatric ward. Secondary outcomes included indications for HFNC, initial and maximum flow rates, maximum FiO2, method of nutrition delivery while on HFNC, level of nursing and respiratory therapist care required, criteria for pediatric intensive care unit transfer, and subjective successes and challenges of implementing a ward-based HFNC policy.

RESULTS

The section chief survey response rate was 100% (15/15). Eight centres (53%) allowed the use of HFNC outside of an intensive care setting. Six centres initiated HFNC on the ward, while two centres only accepted patients after HFNC had been initiated in an intensive care setting. Other practices and policies varied considerably from centre to centre.

CONCLUSION

Our study reveals that approximately half of tertiary children's hospitals in Canada currently use HFNC on the ward and utilize a range of practices and policies. Other centres are considering implementation. Further research is needed to inform best practices for HFNC therapy, support stewardship of health care resources, and promote safe patient care.

Hygrometric Performances of Different High-Flow Nasal Cannula Devices: Bench Evaluation and Clinical Tolerance

BACKGROUND

High-flow nasal cannula (HFNC) is increasingly used for the management of respiratory failure. Settings include [Formula: see text], total gas flow, and temperature target. Resulting absolute humidity (AH) at the nasal cannula may affect clinical tolerance, and optimal settings with respect to hygrometry remain poorly documented.

METHODS

A bench study was designed to assess AH delivered by 4 HFNC devices (Optiflow, Airvo 2, Precision Flow, and Hydrate) according to flow, ambient temperature, and other available settings. Clinical tolerance of different levels of hygrometry (20, 30, and 40 mg H₂O/L) was evaluated in 15 healthy volunteers.

RESULTS

With [Formula: see text] set at 1.0, normal ambient temperature, and settings made accordingly to the manufacturers' recommendations, mean ± SD AH was 42.2 ± 3.1, 39.5 ± 1.8, 35.7 ± 2.0, and 32.9 ± 2.7 mg H₂O/L for the Airvo 2, Optiflow, Hydrate, and Precision Flow, respectively, (P < .001). AH dropped from -3.5 to -10.7 mg H₂O/L (P <. 001) with high ambient temperature, except for the Precision Flow. Increasing flow did not significantly affect AH except for the Precision Flow (from 36.4 ± 1.6 to 29.8 ± 0.2 mg H₂O/L at 10 and 40 L/min, respectively, [P < .001]). The lowest AH was encountered with the Optiflow set with noninvasive ventilation (NIV) mode, without compensation algorithm, and at high ambient temperature (14.2 ± 1.5 mg H₂O/L). In studied subjects, AH significantly affected breathing comfort, reduced from 7.0 ± 1.0 to 3.0 ± 2.0 at 40 and 20 mg H₂O/L, respectively, (P < .001). Comfort was similar at 30 and 40 mg H₂O/L.

CONCLUSIONS

When used according to manufacturer's recommendations and at normal ambient temperature, all the HFNC devices evaluated achieved satisfactory hygrometric output with respect to breathing comfort evaluated in healthy subjects (≥ 30 mg H₂O/L). Substantial differences exist between devices, and optimal knowledge of their working principles is required as inappropriate usage may dramatically alter efficacy and clinical tolerance.

High-flow nasal cannula oxygen therapy in hypoxic patients with COVID-19 pneumonia: A retrospective cohort study confirming the utility of respiratory rate index

Background

Although high-flow nasal cannula (HFNC) oxygen treatment has been frequently used in coronavirus disease 2019 (COVID-19) patients with acute respiratory failure after the 3rd wave of the pandemic in Japan, the usefulness of the indicators of ventilator avoidance, including respiratory rate-oxygenation (ROX) index and other parameters, namely oxygen saturation/fraction of inspired oxygen ratio and respiratory rate (RR), remain unclear.

Methods

Between January and May 2021, our institution treated 189 COVID-19 patients with respiratory failure requiring oxygen, among which 39 patients requiring HFNC treatment were retrospectively analyzed. The group that switched from HFNC treatment to conventional oxygen therapy (COT) was defined as the HFNC success group, and the group that switched from HFNC treatment to a ventilator was defined as the HFNC failure group. We followed the patients’ oxygenation parameters for a maximum of 30 days.

Results

HFNC treatment success occurred in 24 of 39 patients (62%) treated with HFNC therapy. Compared with the HFNC failure group, the HFNC success group had a significantly higher degree of RR improvement in the univariate analysis. Logistic regression analysis of HFNC treatment success adjusting for age, respiratory improvement, and a ROX index ≥5.55 demonstrated that an improved RR was associated with HFNC treatment success. The total COT duration was significantly shorter in the HFNC success group than in the HFNC failure group.

Conclusions

HFNC treatment can be useful for ventilator avoidance and allow the quick withdrawal of oxygen administration. RR improvement may be a convenient, useful, and simple indicator of HFNC treatment success.

An air-locking port and high-flow nasal cannula in non-intubated uniportal video-assisted thoracic surgery for pneumothorax with pulmonary dysfunction: a case report

Background

Non-intubated video-assisted thoracic surgery is a therapeutic option for intractable secondary spontaneous pneumothorax in patients who are poor candidates for surgery with endotracheal intubation under general anesthesia. However, intraoperative respiratory management in this surgery is often challenging because of hypoxia caused by surgical pneumothorax.

Case presentation

A 75-year-old man with idiopathic pulmonary fibrosis who had been on home oxygen therapy underwent non-intubated uniportal video-assisted thoracic surgery for intractable spontaneous pneumothorax. During the operation, oxygen was administered using a high-flow nasal cannula at a high flow rate. An air-locking port for single-incision surgery was used to minimize the inflow of air into the pleural cavity. The intrapleural air was continuously suctioned through the chest tube. The air-leak point was easily identified and closed using ligation. Oxygenation was satisfactory throughout the operation.

Conclusions

Non-intubated uniportal video-assisted thoracic surgery for secondary spontaneous pneumothorax with an air-locking port, continuous pleural suction, and high-flow nasal cannula may achieve satisfactory intraoperative oxygenation in patients with respiratory dysfunction. The intrapleural space can be feasible for surgical manipulation without surgical pneumothorax in non-intubated video-assisted thoracic surgery even when supplied with oxygen at a high flow rate using a high-flow nasal cannula.

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.

Worldwide Clinical Practice of High-Flow Nasal Cannula and Concomitant Aerosol Therapy in the Adult ICU Setting

BACKGROUND

High-flow nasal cannula (HFNC) oxygen therapy has been broadly used. However, no consensus has been achieved on the practical implementation of HFNC and how to provide aerosol delivery during HFNC therapy in adult patients.

METHODS

An online anonymous questionnaire survey endorsed by 4 academic societies from America, Europe, mainland China, and Taiwan was administered from May to December 2019. Clinicians who had worked in adult ICUs for > 1 year and had used HFNC to treat patients within 30 days were included.

RESULTS

A total of 2,279 participants clicked on the survey link, 1,358 respondents completed the HFNC section of the questionnaire, whereas 1,014 completed the whole survey. Postextubation hypoxemia and moderate hypoxemia were major indications for HFNC. The initial flow was mainly set at 40-50 L/min. Aerosol delivery via HFNC was used by 24% of the participants (248/1,014), 30% (74/248) of whom reported reducing flow during aerosol delivery. For the patients who required aerosol treatment during HFNC therapy, 40% of the participants (403/1,014) reported placing a nebulizer with a mask or mouthpiece while pursuing HFNC whereas 33% (331/1,014) discontinued HFNC to use conventional aerosol devices. A vibrating mesh nebulizer was the most commonly used nebulizer (40%) and was mainly placed at the inlet of the humidifier.

CONCLUSIONS

The clinical utilization of HFNC was variable, as were indications, flow settings, and criteria for adjustment. Many practices associated with concomitant aerosol therapy were not consistent with available evidence for optimal use. More efforts are warranted to close the knowledge gap.

The COVID-19 pandemic: the effect on airway Management in non-COVID emergency patients

Background

During the COVID-19 outbreak, healthcare providers might have avoided droplet/aerosol-generating procedures, such as non-invasive ventilation (NIV) and high-flow nasal cannula (HFNC) due to the concern of themselves being infected. We hypothesized that this change of practice could have also occurred to other non-COVID-infected patients in the Emergency Department (ED).

Methods

A retrospective analytic study was conducted in the ED of Siriraj Hospital, Bangkok, Thailand, including adult patients presenting with signs and symptoms of respiratory distress between 1 March and 30 April 2020 (the COVID period). A comparison group using the same inclusion criteria was retrieved from 1 March to 30 April 2019 (the pre-COVID period). The primary outcome was rate of NIV and HFNC use. The secondary outcomes were rate of intubation, failure of NIV and HFNC, complications, and mortality.

Results

A total of 360 and 333 patients were included during the pre-COVID and COVID periods, respectively. After adjusting for baseline differences, patients in the COVID period were less likely to receive either NIV or HFNC than the pre-COVID period (adjusted OR 0.52 [95%CI 0.29–0.92]). Overall, intubation rate was similar between the two study periods. However, patients in respiratory distress with pulmonary edema had a relatively higher intubation rate in the COVID period. There were higher failure rates of NIV and HFNC, more infectious complications, and a higher rate of mortality in the pre-COVID period.

Conclusion

During the COVID-19 pandemic, the overall usage of NIV and HFNC in emergency non-COVID patients decreased. Although not affecting the overall intubation rate, this change of practice could have affected some groups of patients. Therefore, treatment decisions based on a balance between the benefits to the patients and the safety of healthcare providers should be made.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-021-00491-7.

Efficacy of High-Flow Nasal Cannula Oxygen Therapy in Patients with Mild Hypercapnia

Objectives

To investigate the indications of high-flow nasal cannula (HFNC) oxygen therapy among patients with mild hypercapnia and to explore the predictors of intubation when HFNC fails.

Methods

This retrospective study was conducted based on the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Adult patients with mild hypercapnia (45 < PaCO₂ ≤ 60 mmHg) received either HFNC or non-invasive ventilation (NIV) oxygen therapy. Propensity score matching (PSM) was implemented to increase between-group comparability. The Kaplan–Meier method was used to estimate overall survival and cumulative intubation rates, while 28-day mortality and 48-h and 28-day intubation rates were compared using the Chi-squared test. The predictive performances of HR/SpO₂ and the ROX index (the ratio of SpO₂/FiO₂ to respiratory rate) at 4 h were assessed regarding HFNC failure, which was determined if intubation was given within 48 h after the initiation of oxygen therapy. The area under the receiver operating characteristic curve (AUC) for HR/SpO₂ and the ROX index were calculated and compared.

Results

A total of 524,520 inpatient hospitalization records were screened, 106 patients in HFNC group and 106 patients in NIV group were successfully matched. No significant difference in 48-h intubation rate between the HFNC group (the treatment group) and the NIV group (the control group) (14.2% vs. 8.5%, p = 0.278); patients receiving HFNC had higher 28-day intubation rate (26.4% vs. 14.2%, p = 0.029), higher 28-day mortality (17.9% vs. 8.5%, p = 0.043), and longer ICU length of stay (4.4 vs. 3.3 days, p = 0.019), compared to those of NIV group. The AUC of HR/SpO₂ at 4 h after the initiation of HFNC yielded around 0.660 for predicting 48-h intubation, greater than that of the ROX index with an AUC of 0.589 (p < 0.01).

Conclusion

Patients with impending respiratory failure had lower intubation rate, shorter ICU length of stay, and lower mortality when treated mild hypercapnia with NIV over HFNC. As opposed to the ROX index, a modest, yet improved predictive performance is demonstrated using HR/SpO₂ in predicting the failure of HFNC among these patients.

Comparison of High-flow Nasal Cannula (HFNC) and Conventional Oxygen Therapy in Obese Patients Undergoing Cardiac Surgery: A Systematic Review and Meta-analysis

BACKGROUND/AIM

High-flow nasal cannula (HFNC), a new method for postoperative oxygenation, has increasingly received attention during postoperative care. However, its importance for obese patients undergoing cardiac surgery remains controversial. This systematic review and meta-analysis compared and evaluated HFNC and conventional oxygen therapy (COT) in this patient group.

MATERIALS AND METHODS

Literature was retrieved by searching eight public databases. Randomized controlled trials (RCTs) were selected. RevMan 5.3 was used to analyze the results and any potential bias. The primary outcome included atelectasis score at 24 h postoperatively. The secondary outcomes included PaO2/FiO2 (ratio), dyspnea score at 24 h postoperatively, intensive care unit (ICU) length of stay, and reintubation.

RESULTS

The search strategy yielded 382 studies after duplicates were removed. Finally, 3 RCTs with a total of 526 patients were included in the present study. Compared with COT, there was no significant difference in atelectasis score, dyspnea score, reintubation, and ICU length of stay.

CONCLUSION

For obese patients undergoing cardiac surgery, postoperative use of HFNC can maintain patient's oxygenation. Additional clinical studies are needed to investigate the role of HFNC in this patient group.

[Noninvasive ventilation and positional therapy in COVID-19 : Case report and literature review]

If noninvasive ventilation (NIV or high-flow CPAP) fails in severe cases of COVID-19, escalation of treatment with orotracheal intubation and intermitted prone positioning is provided as standard care. The present case reports show two COVID-19 patients with severe refractory hypoxemia despite NIV treatment during the first wave (first half year 2020) and the resulting influence on the treatment regimen during the second wave (since October 2020) of the pandemic. Both patients (aged 63 years and 77 years) voluntarily positioned themselves on the side or in a prone position without prior sedation and oral intubation. Positional treatment promptly improved the arterial oxygenation level. The oxygenation index improved in the following days with continued NIV and intermittent prone and side position. The recovered patients were transferred from the intensive care unit at days 5 and 14, respectively after admission. The case reports, along with other reports, show that prone or lateral positioning may be important in the treatment of SARS-CoV‑2 pneumonia in awake and not yet intubated patients.

High flow nasal cannula for adult acute hypoxemic respiratory failure in the ED setting: A narrative review

Introduction

High flow nasal cannula (HFNC) is a noninvasive ventilation (NIV) system that has demonstrated promise in the emergency department (ED) setting.

Objective

This narrative review evaluates the utility of HFNC in adult patients with acute hypoxemic respiratory failure in the ED setting.

Discussion

HFNC provides warm (37 °C), humidified (100% relative humidity) oxygen at high flows with a reliable fraction of inspired oxygen (FiO₂). HFNC can improve oxygenation, reduce airway resistance, provide humidified flow that can flush anatomical dead space, and provide a low amount of positive end expiratory pressure. Recent literature has demonstrated efficacy in acute hypoxemic respiratory failure, including pneumonia, acute respiratory distress syndrome (ARDS), coronavirus disease 2019 (COVID-19), interstitial lung disease, immunocompromised states, the peri-intubation state, and palliative care, with reduced need for intubation, length of stay, and mortality in some of these conditions. Individual patient factors play an important role in infection control risks with respect to the use of HFNC in patients with COVID-19. Appropriate personal protective equipment, adherence to hand hygiene, surgical mask placement over the HFNC device, and environmental controls promoting adequate room ventilation are the foundation for protecting healthcare personnel. Frequent reassessment of the patient placed on HFNC is necessary; those with severe end organ dysfunction, thoracoabdominal asynchrony, significantly increased respiratory rate, poor oxygenation despite HFNC, and tachycardia are at increased risk of HFNC failure and need for further intervention.

Conclusions

HFNC demonstrates promise in several conditions requiring respiratory support. Further randomized trials are needed in the ED setting.

Non-invasive respiratory support paths in hospitalized patients with COVID-19: proposal of an algorithm

COVID-19 related Acute Respiratory Failure, may be successfully treated with Conventional Oxygen therapy, High Flow Nasal Cannula, Continuous Positive Airway Pressure or Bi-level Positive-Pressure ventilation. Despite the accumulated data in favor of the use of different Non-invasive Respiratory therapies in COVID-19 related Acute Respiratory Failure, it is not fully understood when start, escalate and de-escalate the best respiratory supportive option for the different timing of the disease. Based on the current published experience with Non-invasive Respiratory therapies in COVID-19 related Acute Respiratory Failure, we propose an algorithm in deciding when to start, when to stop and when to wean different NIRT. This strategy may help clinicians in better choosing NIRT during this second COVID-19 wave and beyond.

High-flow nasal cannula compared with continuous positive airway pressure in the treatment of obstructive sleep apnea

PURPOSE

Continuous positive airway pressure (CPAP) is a standard treatment for obstructive sleep apnea (OSA). However, CPAP has limitations. High-flow nasal cannula (HFNC) is already in use for various types of respiratory diseases. As HFNC generates positive airway pressure, it may be a potential candidate for OSA treatment. This prospective study compared the therapeutic effects of HFNC to CPAP in patients with OSA.

METHODS

Patients whose apnea-hypopnea index (AHI) was > 5 events/h were enrolled in this study. All participants were randomly divided into two groups. The first group underwent CPAP the first night and HFNC the second night. Conversely, the second group received HFNC the first night and CPAP the second night. Their respiratory events and sleep quality were compared using baseline polysomnography, CPAP, and HFNC.

RESULTS

In total, 28 participants completed this study. Median [interquartile range] AHI (35.0 [20.0-48.6] vs. 10.8 [5.5-20.6] events/h; p < 0.001) was significantly improved by the HFNC. However, sleep quality was not improved. When CPAP was compared directly with HFNC, CPAP demonstrated a more favorable effect for respiratory events (AHI 5.0 [2.0-7.0] vs. 10.8 [5.5-20.6] events/h; p < 0.001) and sleep efficiency (88.1 [79.9-92.5] vs. 77.9 [69.2-86.6] %; p = 0.001).

CONCLUSION

The efficacy of CPAP was superior to HFNC for both respiratory events and sleep quality.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03843372; URL: www.clinicaltrials.gov ; Date of registration: November 2, 2019.

Comparison of high-flow nasal oxygen cannula therapy versus a standard oxygen face mask in patients with hypostatic pneumonia

Objective

We assessed the clinical effects of high-flow nasal cannula (HFNC) oxygen therapy and a standard oxygen atomizer mask on the respiratory tract in patients with hypostatic pneumonia.

Methods

We included patients with hypostatic pneumonia in this retrospective cohort study. Patients were provided continuous airway humidification by continuous oxygen atomization using either an HFNC or standard oxygen mask. Arterial blood gas analysis, the dyspnea score, inflammatory-related parameters, and adverse events of patients in the two groups were compared.

Results

Fifty-five patients had HFNC delivery and 57 had a standard oxygen atomizer mask. After 7 days of treatment, patients in the HFNC group had a higher partial pressure of arterial blood oxygen/fraction of inspired oxygen ratio (268.12±28.44 vs 238.28±30.04) and lower partial pressure of arterial blood carbon dioxide (38.02±8.84 vs 49.27±7.84 mmHg) than those in the standard oxygen mask group. The dyspnea score and inflammatory-related parameters in the HFNC group were significantly lower than those in the standard oxygen mask group. The incidence of adverse events was lower in the HFNC group than in the standard oxygen mask group.

Conclusion

HFNC therapy relieves clinical symptoms more quickly than a standard oxygen mask and reduces the incidence of adverse events.

Clinical impact of implementing humidified high-flow nasal cannula on interhospital transport among children admitted to a PICU with respiratory distress: a cohort study

Background

There is a limited evidence for humidified high-flow nasal cannula (HHFNC) use on inter-hospital transport. Despite this, its use during transport is increasing in children with respiratory distress worldwide. In 2015 HHFNC was implemented on a specialized pediatric retrieval team serving for Victoria. The aim of this study is to investigate the effect of the HHFNC implementation on the retrieval team on the paediatric intensive care unit (PICU) length of stay and respiratory support use.

Methods

We performed a cohort study using a comparative interrupted time-series approach controlling for patient and temporal covariates, and population-adjusted analysis. We studied 3022 children admitted to a PICU in Victoria with respiratory distress January 2010–December 2019. Patients were divided in pre-intervention era (2010–2014) and post-intervention era (2015–2019).

Results

1006 children following interhospital transport and 2016 non-transport children were included. Median (IQR) age was 1.4 (0.7–4.5) years. Pneumonia (39.1%) and bronchiolitis (34.3%) were common. On retrieval, HHFNC was used in 5.0% (21/420) and 45.9% (269/586) in pre- and post-intervention era. In an unadjusted model, median (IQR) PICU length of stay was 2.2 (1.1–4.2) and 1.7 (0.9–3.2) days in the pre- and post-intervention era in transported children while the figures were 2.4 (1.3–4.9) and 2.1 (1.2–4.5) days in non-transport children. In the multivariable regression model, the intervention was associated with the reduced PICU length of stay (ratio 0.64, 95% confidential interval 0.49–0.83, p = 0.001) with the predicted reduction of PICU length of stay being − 10.6 h (95% confidential interval − 16.9 to − 4.3 h), and decreased respiratory support use (− 25.1 h, 95% confidential interval − 47.9 to − 2.3 h, p = 0.03). Sensitivity analyses including a model excluding less severe children showed similar results. In population-adjusted analyses, respiratory support use decreased from 4837 to 3477 person-hour per year in transported children over the study era, while the reduction was 594 (from 9553 to 8959) person-hour per year in non-transport children. With regard to the safety, there were no escalations of respiratory support mode during interhospital transport.

Conclusions

The implementation of HHFNC on interhospital transport was associated with the reduced PICU length of stay and respiratory support use among PICU admissions with respiratory distress.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03620-7.

Effects of high-flow oxygen therapy on patients with hypoxemia after extubation and predictors of reintubation: a retrospective study based on the MIMIC-IV database

BACKGROUND

To investigate the indications for high-flow nasal cannula oxygen (HFNC) therapy in patients with hypoxemia during ventilator weaning and to explore the predictors of reintubation when treatment fails.

METHODS

Adult patients with hypoxemia weaning from mechanical ventilation were identified from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. The patients were assigned to the treatment group or control group according to whether they were receiving HFNC or non-invasive ventilation (NIV) after extubation. The 28-day mortality and 28-day reintubation rates were compared between the two groups after Propensity score matching (PSM). The predictor for reintubation was formulated according to the risk factors with the XGBoost algorithm. The areas under the receiver operating characteristic curve (AUC) was calculated for reintubation prediction according to values at 4 h after extubation, which was compared with the ratio of SpO2/FiO2 to respiratory rate (ROX index).

RESULTS

A total of 524,520 medical records were screened, and 801 patients with moderate or severe hypoxemia when undergoing mechanical ventilation weaning were included (100 < PaO2/FiO2 ≤ 300 mmHg), including 358 patients who received HFNC therapy after extubation in the treatment group. There were 315 patients with severe hypoxemia (100 < PaO2/FiO2 ≤ 200 mmHg) before extubation, and 190 patients remained in the treatment group with median oxygenation index 166[157,180] mmHg after PSM. There were no significant differences in the 28-day reintubation rate or 28-day mortality between the two groups with moderate or severe hypoxemia (all P > 0.05). Then HR/SpO2 was formulated as a predictor for 48-h reintubation according to the important features predicting weaning failure. According to values at 4 h after extubation, the AUC of HR/SpO2 was 0.657, which was larger than that of ROX index (0.583). When the HR/SpO2 reached 1.2 at 4 h after extubation, the specificity for 48-h reintubation prediction was 93%.

CONCLUSIONS

The treatment effect of HFNC therapy is not inferior to that of NIV, even on patients with oxygenation index from 160 to 180 mmHg when weaning from ventilator. HR/SpO2 is more early and accurate in predicting HFNC failure than ROX index.

Impact of prone position in non-intubated spontaneously breathing patients admitted to the ICU for severe acute respiratory failure due to COVID-19

PURPOSE

Studies performed in spontaneously breathing patients with mild to moderate respiratory failure suggested that prone position (PP) in COVID-19 could be beneficial.

MATERIALS AND METHODS

Consecutive critically ill patients with COVID-19 were enrolled in four ICUs. PP sessions lasted at least 3 h each and were performed twice daily. A Cox proportional hazard model identified factors associated with the need of intubation. A propensity score overlap weighting analysis was performed to assess the association between spontaneous breathing PP (SBPP) and intubation.

RESULTS

Among 379 patients, 40 underwent SBPP. Oxygenation was achieved by high flow nasal canula in all but three patients. Duration of proning was 2.5 [1.6;3.4] days. SBPP was well tolerated hemodynamically, increased PaO₂/FiO₂ (78 [68;96] versus 63 [53;77] mm Hg, p = 0.004) and PaCO₂ (38 [34;43] versus 35 [32;38] mm Hg, p = 0.005). Neither day-28 survival (HR 0.51, 95% CI 0.16-1.16] nor risk of invasive ventilation [sHR 0.96; 95% CI 0.49;1.88] differed between patients who underwent PP and others.

CONCLUSIONS

SBPP in COVID-19 is feasible and well tolerated in severely hypoxemic patients. It did not induce any effect on risk of intubation and day-28 mortality.

Association of noninvasive respiratory support with mortality and intubation rates in acute respiratory failure: a systematic review and network meta-analysis

BACKGROUND

Noninvasive respiratory support devices may reduce the tracheal intubation rate compared with conventional oxygen therapy (COT). To date, few studies have compared high-flow nasal cannula (HFNC) use with noninvasive positive-pressure ventilation (NPPV). We conducted a network meta-analysis to compare the effectiveness of three respiratory support devices in patients with acute respiratory failure.

METHODS

The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and Ichushi databases were searched. Studies including adults aged ≥ 16 years with acute hypoxic respiratory failure and randomized-controlled trials that compared two different oxygenation devices (COT, NPPV, or HFNC) before tracheal intubation were included. A frequentist-based approach with a multivariate random-effects meta-analysis was used. The network meta-analysis was performed using the GRADE Working Group approach. The outcomes were short-term mortality and intubation rate.

RESULTS

Among 5507 records, 27 studies (4618 patients) were included. The main cause of acute hypoxic respiratory failure was pneumonia. Compared with COT, NPPV and HFNC use tended to reduce mortality (relative risk, 0.88 and 0.93, respectively; 95% confidence intervals, 0.76-1.01 and 0.80-1.08, respectively; both low certainty) and lower the risk of endotracheal intubation (0.81 and 0.78; 0.72-0.91 and 0.68-0.89, respectively; both low certainty); however, short-term mortality or intubation rates did not differ (0.94 and 1.04, respectively; 0.78-1.15 and 0.88-1.22, respectively; both low certainty) between NPPV and HFNC use.

CONCLUSION

NPPV and HFNC use are associated with a decreased risk of endotracheal intubation; however, there are no significant differences in short-term mortality.

TRIAL REGISTRATION

PROSPERO (registration number: CRD42020139105 , 01/21/2020).