High-flow oxygen via nasal cannulae in patients with acute hypoxemic respiratory failure: a systematic review and meta-analysis

Combining reservoir mask oxygenation with high-flow nasal cannula in the treatment of hypoxemic respiratory failure among patients with COVID-19 pneumonia: a retrospective cohort study

BACKGROUND

Concerns regarding positive-pressure-ventilation for the treatment of coronavirus disease 2019 (COVID-19) hypoxemia led the search for alternative oxygenation techniques. This study aimed to assess one such method, dual oxygenation, i.e., the addition of a reservoir mask (RM) on top of a high-flow nasal cannula (HFNC).

METHODS

In this retrospective cohort study, the records of all patients hospitalized with COVID-19 during 2020-2022 were reviewed. Patients over the age of 18 years with hypoxemia necessitating HFNC were included. Exclusion criteria were positive-pressure-ventilation for any indication other than hypoxemic respiratory failure, transfer to another facility while still on HFNC and "do-not-intubate/resuscitate" orders. The primary outcome was mortality within 30 days from the first application of HFNC. Secondary outcomes were intubation and admission to the intensive care unit.

RESULTS

Of 659 patients included in the final analysis, 316 were treated with dual oxygenation and 343 with HFNC alone. Propensity for treatment was estimated based on background diagnoses, laboratories and vital signs upon admission, gender and glucocorticoid dose. Inverse probability of treatment weighted regression including age, body mass index, Sequential Organ Failure Assessment (SOFA) score and respiratory rate oxygenation index showed treatment with dual oxygenation to be associated with lower 30-day mortality (adjusted hazard ratio, 0.615; 95% confidence interval, 0.469-0.809). Differences in the secondary outcomes did not reach statistical significance.

CONCLUSIONS

Our study suggests that the addition of RM on top of HFNC may be associated with decreased mortality in patients with severe COVID-19 hypoxemia.

Performance of the ROX index in predicting high flow nasal cannula failure in COVID-19 patients: a systematic review and meta-analysis

COVID-19 patients with acute hypoxemic respiratory failure (AHRF) benefit from high flow nasal cannula (HFNC) oxygen therapy. However, delays in initiating invasive ventilation after HFNC failure are associated with poorer outcomes. The respiratory oxygenation (ROX) index, combining SpO2/FiO2 and respiratory rate, can predict HFNC failure. This meta-analysis evaluated the optimal ROX index cut-offs in predicting HFNC failure among COVID-19 patients at different measurement timings and clinical settings. Three databases were searched for eligible papers. From each study, we reconstructed the confusion matrices at different cut-offs, fitted linear mixed models to estimate the ROX index distribution function, and derived the area under the summary receiver operator characteristic curve (sAUC) and optimal cut-offs to predict HFNC failure. 24 studies containing 4790 patients were included. Overall sAUC was 0.771 (95% CI: 0.666-0.847) (optimal cut-off: 5.23, sensitivity: 0.732, specificity: 0.690). The cut-off values to achieve 80%, 90% sensitivity, 80%, 90% specificity were 5.70, 6.69, 4.45, 3.37, respectively. We stratified the analysis by ROX measurement time and estimated optimal cut-offs and cut-offs to achieve 80% sensitivity and specificity. For 2-6 h and 6-12 h post-HFNC initiation, we propose the use of 80% specific cut-offs to rule in HFNC failure of < 5.33 and < 3.69, respectively. For 12-24 h post-HFNC initiation, we propose the use of the 80% sensitive cut-off of > 6.07 to rule out HFNC failure. Our analysis confirms the overall utility of the ROX index in risk stratification of COVID-19 patients with AHRF receiving HFNC and provides potentially useful cut-offs for different times from HFNC initiation.

Interventions to improve outcomes in community-acquired pneumonia

INTRODUCTION

Community-acquired pneumonia (CAP) is a common infection associated with high morbimortality and a highly deleterious impact on patients' quality of life and functionality. We comprehensively review the factors related to the host, the causative microorganism, the therapeutic approach and the organization of health systems (e.g. setting for care and systems for allocation) that might have an impact on CAP-associated outcomes. Our main aims are to discuss the most controversial points and to provide some recommendations that may guide further research and the management of patients with CAP, in order to improve their outcomes, beyond mortality.

AREA COVERED

In this review, we aim to provide a critical account of potential measures to improve outcomes of CAP and the supporting evidence from observational studies and clinical trials.

EXPERT OPINION

CAP is associated with high mortality and a highly deleterious impact on patients' quality of life. To improve CAP-associated outcomes, it is important to understand the factors related to the patient, etiology, therapeutics, and the organization of health systems.

The Impact of High-Flow Nasal Cannula Therapy on Acute Respiratory Distress Syndrome Patients: A Systematic Review

High-flow nasal cannula (HFNC) is a novel oxygenation approach in the management of acute respiratory distress syndrome (ARDS). This systematic review was focused on evaluating current evidence concerning the efficacy of HFNC in ARDS and its comparison with standard treatment approaches. For this review, a systematic search was undertaken in PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, Web of Science, Cochrane Library, and Google Scholar to identify relevant studies. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. All those studies that investigated the impact of HFNC on ARDS patients and were published in the English language were included. The literature search from all databases provided 6157 potentially relevant articles from PubMed (n = 1105), CINAHL (n = 808), Web of Science (n = 811), Embase (n = 2503), Cochrane database (n = 930), and Google Scholar (n = 46). After the exclusion of studies that did not fulfill the criteria, 18 studies were shortlisted for the scope of this systematic review. Among the included studies, five focused on HFNC's impact on COVID-19-related ARDS, whereas 13 studies focused on HFNC's impact on ARDS patients. Most studies demonstrated the efficacy of HFNC in managing ARDS, with some studies showing comparable efficacy and higher safety compared to noninvasive ventilation (NIV). This systematic review highlights the potential benefits of HFNC in ARDS management. The findings show that HFNC is effective in reducing the respiratory distress symptoms, the incidence of invasive ventilation, and the adverse events associated with ARDS. These findings can help clinical decision-making processes and contribute to the evidence base for optimal ARDS management strategies.

Factors influencing health professionals' use of high-flow nasal cannula therapy for infants with bronchiolitis - A qualitative study

Aim

To explore the factors influencing the use of high-flow nasal cannula (HFNC) therapy for infants with bronchiolitis.

Design

Qualitative approach using semi-structured interviews.

Methods

The semi-structured interviews (face-to-face or virtual) were conducted between September 2020 and February 2021. Deductive content analysis was used to map key influencing factors for use of HFNC therapy to the Theoretical Domains Framework (TDF).

Results

Nineteen interviews were undertaken before reaching thematic saturation (7 nurses, 12 doctors) in emergency departments and paediatric wards from four purposively selected hospitals in Australia and New Zealand. Influencing factors were mapped to eight domains in the TDF with 21 themes identified. Main findings included: (1) Health professionals' expectations of HFNC therapy on patient deterioration, work of breathing and oxygenation; (2) Staff emotions relating to concern and anxiety about deterioration and "need to do something"; (3) Social influences from other health professionals and parents and (4) Environmental factors relating to logistics of care and patient transfer considerations. These factors, combined with the ready availability of HFNC equipment and health professionals having the required skills to administer the therapy, contributed to its initiation.

Conclusion

Individual/personal and contextual/environmental factors contribute to the use of HFNC therapy for infants with bronchiolitis. It is evident these influences contribute substantially to increased use, despite evidence-based guidelines recommending a more nuanced approach to this therapy. These findings will inform a targeted implementation intervention to promote evidence-based use of HFNC therapy in infants with bronchiolitis.

Prevalence of high flow nasal cannula therapy use for management of infants with bronchiolitis in Australia and New Zealand

AIM

To determine the prevalence of high flow nasal cannula (HFNC) therapy in infants presenting to hospital in Australia and New Zealand with bronchiolitis over four bronchiolitis seasons. Secondary aims were to determine temporal trends in HFNC use, and associations between HFNC, hospital length of stay (LOS) and intensive care unit (ICU) admission.

METHODS

A planned sub-study of a multi-centre international cluster randomised controlled trial investigating knowledge translation strategies for a bi-national bronchiolitis guideline. Demographics, management and outcomes data were collected retrospectively for infants presenting with bronchiolitis to 26 hospitals between 1 May 2014 and 30 November 2017. Prevalence data are presented as absolute frequencies (95% confidence interval (CI)) with differences between groups for continuous and categorical variables analysed using linear and logistic regression, respectively.

RESULTS

11 715 infants were included with 3392 (29.0%, 95% CI (28.1-29.8%)) receiving oxygen therapy; of whom 1817 (53.6%, 95% CI (51.9-55.3%)) received HFNC. Use of oxygen therapy did not change over the four bronchiolitis seasons (P = 0.12), while the proportion receiving HFNC increased (2014, 336/2587 (43.2%); 2017, 609/3720 (57.8%); P ≤ 0.001). Infants who received HFNC therapy were not substantially different to infants who received oxygen therapy without HFNC. HFNC use was associated with increases in both hospital LOS (P < 0.001) and ICU admissions (P < 0.001).

CONCLUSION

Use of HFNC therapy for infants with bronchiolitis increased over 4 years. Of those who received oxygen therapy, the majority received HFNC therapy without improvement in hospital LOS or ICU admissions. Strategies to guide appropriate HFNC use in infants with bronchiolitis are required.

Factors associated with failure of high-flow nasal cannula oxygen therapy in patients with severe COVID-19: a retrospective case series

Objective

To identify factors associated with high-flow nasal cannula (HFNC) therapy failure in patients with severe COVID-19.

Methods

We retrospectively examined clinical and laboratory data upon admission, treatments, and outcomes of patients with severe COVID-19. Sequential Organ Failure Assessment (SOFA) scores were also calculated.

Results

Of 54 patients with severe COVID-19, HFNC therapy was successful in 28 (51.9%) and unsuccessful in 26 (48.1%). HFNC therapy failure was more common in patients aged ≥60 years and in men. Compared with patients with successful HFNC therapy, patients with HFNC therapy failure had higher percentages of fatigue, anorexia, and cardiovascular disease; a longer time from symptom onset to diagnosis; higher SOFA scores; a higher body temperature, respiratory rate, and heart rate; more complications, including acute respiratory distress syndrome, septic shock, myocardial damage, and acute kidney injury; a higher C-reactive protein concentration, neutrophil count, and prothrombin time; and a lower arterial partial pressure of oxygen/fraction of inspired oxygen (PaO₂/FiO₂). However, male sex, a low PaO₂/FiO₂, and a high SOFA score were the only independent factors significantly associated with HFNC therapy failure.

Conclusions

Male sex, a low PaO₂/FiO₂, and a high SOFA score were independently associated with HFNC therapy failure in patients with severe COVID-19.

Management of Adult Patients With Oxygen in the Acute Care Setting

Providing supplemental oxygen to hospitalized adults is a frequent practice and can be administered via a variety of devices. Oxygen therapy has evolved over the years, and clinicians should follow evidence-based practices to provide maximum benefit and avoid harm. This systematic review and subsequent clinical practice guidelines were developed to answer questions about oxygenation targets, monitoring, early initiation of high-flow oxygen (HFO), benefits of HFO compared to conventional oxygen therapy, and humidification of supplemental oxygen. Using a modification of the RAND/UCLA Appropriateness Method, 7 recommendations were developed to guide the delivery of supplemental oxygen to hospitalized adults: (1) aim for S_pO2 range of 94-98% for most hospitalized patients (88-92% for those with COPD), (2) the same S_pO2 range of 94-98% for critically ill patients, (3) promote early initiation of HFO, (4) consider HFO to avoid escalation to noninvasive ventilation, (5) consider HFO immediately postextubation to avoid re-intubation, (6) either HFO or conventional oxygen therapy may be used with patients who are immunocompromised, and (7) consider humidification for supplemental oxygen when flows > 4 L/min are used.

The Role of Noninvasive Respiratory Management in Patients with Severe COVID-19 Pneumonia

Acute hypoxemic respiratory failure is the principal cause of hospitalization, invasive mechanical ventilation and death in severe COVID-19 infection. Nearly half of intubated patients with COVID-19 eventually die. High-Flow Nasal Oxygen (HFNO) and Noninvasive Ventilation (NIV) constitute valuable tools to avert endotracheal intubation in patients with severe COVID-19 pneumonia who do not respond to conventional oxygen treatment. Sparing Intensive Care Unit beds and reducing intubation-related complications may save lives in the pandemic era. The main drawback of HFNO and/or NIV is intubation delay. Cautious selection of patients with severe hypoxemia due to COVID-19 disease, close monitoring and appropriate employment and titration of HFNO and/or NIV can increase the rate of success and eliminate the risk of intubation delay. At the same time, all precautions to protect the healthcare personnel from viral transmission should be taken. In this review, we summarize the evidence supporting the application of HFNO and NIV in severe COVID-19 hypoxemic respiratory failure, analyse the risks associated with their use and provide a path for their proper implementation.

Effectiveness and Harms of High-Flow Nasal Oxygen for Acute Respiratory Failure: An Evidence Report for a Clinical Guideline From the American College of Physicians

BACKGROUND

Use of high-flow nasal oxygen (HFNO) for treatment of adults with acute respiratory failure (ARF) has increased.

PURPOSE

To assess HFNO versus noninvasive ventilation (NIV) or conventional oxygen therapy (COT) for ARF in hospitalized adults.

DATA SOURCES

English-language searches of MEDLINE, Embase, CINAHL, and Cochrane Library from January 2000 to July 2020; systematic review reference lists.

STUDY SELECTION

29 randomized controlled trials evaluated HFNO versus NIV (k = 11) or COT (k = 21).

DATA EXTRACTION

Data extraction by a single investigator was verified by a second, 2 investigators assessed risk of bias, and evidence certainty was determined by consensus.

DATA SYNTHESIS

Results are reported separately for HFNO versus NIV, for HFNO versus COT, and by initial or postextubation management. Compared with NIV, HFNO may reduce all-cause mortality, intubation, and hospital-acquired pneumonia and improve patient comfort in initial ARF management (low-certainty evidence) but not in postextubation management. Compared with COT, HFNO may reduce reintubation and improve patient comfort in postextubation ARF management (low-certainty evidence).

LIMITATIONS

Trials varied in populations enrolled, ARF causes, and treatment protocols. Trial design, sample size, duration of treatment and follow-up, and results reporting were often insufficient to adequately assess many outcomes. Protocols, clinician and health system training, cost, and resource use were poorly characterized.

CONCLUSION

Compared with NIV, HFNO as initial ARF management may improve several clinical outcomes. Compared with COT, HFNO as postextubation management may reduce reintubations and improve patient comfort; HFNO resulted in fewer harms than NIV or COT. Broad applicability, including required clinician and health system experience and resource use, is not well known.

PRIMARY FUNDING SOURCE

American College of Physicians. (PROSPERO: CRD42019146691).

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.

Derivation and validation of actionable quality indicators targeting reductions in complications for injury admissions

PURPOSE

Approximately, one out of five patients hospitalized following injury will develop at least one hospital complication, more than three times that observed for general admissions. We currently lack actionable Quality Indicators (QI) targeting specific complications in this population. We aimed to derive and validate QI targeting hospital complications for injury admissions and develop algorithms to identify patient charts to review.

METHODS

We conducted a retrospective cohort study including patients with major trauma admitted to any level I or II adult trauma center an integrated Canadian trauma system (2014-2019). We used the trauma registry to develop five QI targeting deep vein thrombosis/pulmonary embolism (DVT/PE), decubitus ulcers, delirium, pneumonia and urinary tract infection (UTI). We developed algorithms to identify patient charts to revise on consultation with a group of clinical experts.

RESULTS

The study population included 14,592 patients of whom 5.3% developed DVT or PE, 2.7% developed a decubitus ulcer, 8.6% developed delirium, 14.7% developed pneumonia and 7.3% developed UTI. The indicators demonstrated excellent predictive performance (Area Under the Curve 0.81-0.87). We identified 4 hospitals with a higher than average incidence of at least one of the targeted complications. The algorithms identified on average 50 and 20 charts to be reviewed per year for level I and II centers, respectively.

CONCLUSION

In line with initiatives to improve the quality of trauma care, we propose QI targeting reductions in hospital complications for injury admissions and algorithms to generate case lists to facilitate the review of patient charts.

The Impact of High-Flow Nasal Cannula Use on Patient Mortality and the Availability of Mechanical Ventilators in COVID-19

Rationale: How to provide advanced respiratory support for coronavirus disease (COVID-19) to maximize population-level survival while optimizing mechanical ventilator access is unknown.Objectives: To evaluate the use of high-flow nasal cannula for COVID-19 on population-level mortality and ventilator availability.Methods: We constructed dynamical (deterministic) simulation models of high-flow nasal cannula and mechanical ventilation use for COVID-19 in the United States. Model parameters were estimated through consensus based on published literature, local data, and experience. We had the following two outcomes: 1) cumulative number of deaths and 2) days without any available ventilators. We assessed the impact of various policies for the use of high-flow nasal cannula (with or without "early intubation") versus a scenario in which high-flow nasal cannula was unavailable.Results: The policy associated with the fewest deaths and the least time without available ventilators combined the use of high-flow nasal cannula for patients not urgently needing ventilators with the use of early mechanical ventilation for these patients when at least 10% of ventilator supply was not in use. At the national level, this strategy resulted in 10,000-40,000 fewer deaths than if high-flow nasal cannula were not available. In addition, with moderate national ventilator capacity (30,000-45,000 ventilators), this strategy led to up to 25 (11.8%) fewer days without available ventilators. For a 250-bed hospital with 100 mechanical ventilators, the availability of 13, 20, or 33 high-flow nasal cannulas prevented 81, 102, and 130 deaths, respectively.Conclusions: The use of high-flow nasal cannula coupled with early mechanical ventilation when supply is sufficient results in fewer deaths and greater ventilator availability.

Prolonged Weaning: S2k Guideline Published by the German Respiratory Society

Mechanical ventilation (MV) is an essential part of modern intensive care medicine. MV is performed in patients with severe respiratory failure caused by respiratory muscle insufficiency and/or lung parenchymal disease; that is, when other treatments such as medication, oxygen administration, secretion management, continuous positive airway pressure (CPAP), or nasal high-flow therapy have failed. MV is required for maintaining gas exchange and allows more time to curatively treat the underlying cause of respiratory failure. In the majority of ventilated patients, liberation or "weaning" from MV is routine, without the occurrence of any major problems. However, approximately 20% of patients require ongoing MV, despite amelioration of the conditions that precipitated the need for it in the first place. Approximately 40-50% of the time spent on MV is required to liberate the patient from the ventilator, a process called "weaning". In addition to acute respiratory failure, numerous factors can influence the duration and success rate of the weaning process; these include age, comorbidities, and conditions and complications acquired during the ICU stay. According to international consensus, "prolonged weaning" is defined as the weaning process in patients who have failed at least 3 weaning attempts, or require more than 7 days of weaning after the first spontaneous breathing trial (SBT). Given that prolonged weaning is a complex process, an interdisciplinary approach is essential for it to be successful. In specialised weaning centres, approximately 50% of patients with initial weaning failure can be liberated from MV after prolonged weaning. However, the heterogeneity of patients undergoing prolonged weaning precludes the direct comparison of individual centres. Patients with persistent weaning failure either die during the weaning process, or are discharged back to their home or to a long-term care facility with ongoing MV. Urged by the growing importance of prolonged weaning, this Sk2 Guideline was first published in 2014 as an initiative of the German Respiratory Society (DGP), in conjunction with other scientific societies involved in prolonged weaning. The emergence of new research, clinical study findings and registry data, as well as the accumulation of experience in daily practice, have made the revision of this guideline necessary. The following topics are dealt with in the present guideline: Definitions, epidemiology, weaning categories, underlying pathophysiology, prevention of prolonged weaning, treatment strategies in prolonged weaning, the weaning unit, discharge from hospital on MV, and recommendations for end-of-life decisions. Special emphasis was placed on the following themes: (1) A new classification of patient sub-groups in prolonged weaning. (2) Important aspects of pulmonary rehabilitation and neurorehabilitation in prolonged weaning. (3) Infrastructure and process organisation in the care of patients in prolonged weaning based on a continuous treatment concept. (4) Changes in therapeutic goals and communication with relatives. Aspects of paediatric weaning are addressed separately within individual chapters. The main aim of the revised guideline was to summarize both current evidence and expert-based knowledge on the topic of "prolonged weaning", and to use this information as a foundation for formulating recommendations related to "prolonged weaning", not only in acute medicine but also in the field of chronic intensive care medicine. The following professionals served as important addressees for this guideline: intensivists, pulmonary medicine specialists, anaesthesiologists, internists, cardiologists, surgeons, neurologists, paediatricians, geriatricians, palliative care clinicians, rehabilitation physicians, intensive/chronic care nurses, physiotherapists, respiratory therapists, speech therapists, medical service of health insurance, and associated ventilator manufacturers.

High-Flow Nasal Cannula Therapy for Exertional Dyspnea in Patients with Cancer: A Pilot Randomized Clinical Trial

BACKGROUND

Exertional dyspnea is common in patients with cancer and limits their function. The impact of high-flow nasal cannula on exertional dyspnea in nonhypoxemic patients is unclear. In this double-blind, parallel-group, randomized trial, we assessed the effect of flow rate (high vs. low) and gas (oxygen vs. air) on exertional dyspnea in nonhypoxemic patients with cancer.

PATIENTS AND METHODS

Patients with cancer with oxygen saturation >90% at rest and exertion completed incremental and constant work (80% maximal) cycle ergometry while breathing low-flow air at 2 L/minute. They were then randomized to receive high-flow oxygen, high-flow air, low-flow oxygen, or low-flow air while performing symptom-limited endurance cycle ergometry at 80% maximal. The primary outcome was modified 0-10 Borg dyspnea intensity scale at isotime. Secondary outcomes included dyspnea unpleasantness, exercise time, and adverse events.

RESULTS

Seventy-four patients were enrolled, and 44 completed the study (mean age 63; 41% female). Compared with low-flow air at baseline, dyspnea intensity was significantly lower at isotime with high-flow oxygen (mean change, -1.1; 95% confidence interval [CI], -2.1, -0.12) and low-flow oxygen (-1.83; 95% CI, -2.7, -0.9), but not high-flow air (-0.2; 95% CI, -0.97, 0.6) or low-flow air (-0.5; 95% CI, -1.3, 0.4). Compared with low-flow air, high-flow oxygen also resulted in significantly longer exercise time (difference + 2.5 minutes, p = .009), but not low-flow oxygen (+0.39 minutes, p = .65) or high-flow air (+0.63 minutes, p = .48). The interventions were well tolerated without significant adverse effects.

CONCLUSION

Our preliminary findings support that high-flow oxygen improved both exertional dyspnea and exercise duration in nonhypoxemic patients with cancer. (ClinicalTrials.gov ID: NCT02357134).

IMPLICATIONS FOR PRACTICE

In this four-arm, double-blind, randomized clinical trial examining the role of high-flow nasal cannula on exertional dyspnea in patients with cancer without hypoxemia, high-flow oxygen, but not high-flow air, resulted in significantly lower dyspnea scores and longer exercise time. High-flow oxygen delivered by high-flow nasal cannula devices may improve clinically relevant outcomes even in patients without hypoxemia.

High-Flow Oxygen and High-Flow Air for Dyspnea in Hospitalized Patients with Cancer: A Pilot Crossover Randomized Clinical Trial

BACKGROUND

The effect of high-flow oxygen (HFOx) and high-flow air (HFAir) on dyspnea in nonhypoxemic patients is not known. We assessed the effect of HFOx, HFAir, low-flow oxygen (LFOx), and low-flow air (LFAir) on dyspnea.

SUBJECTS, MATERIALS, AND METHODS

This double-blind, 4×4 crossover clinical trial enrolled hospitalized patients with cancer who were dyspneic at rest and nonhypoxemic (oxygen saturation >90% on room air). Patients were randomized to 10 minutes of HFOx, HFAir, LFOx, and LFAir in different orders. The flow rate was titrated between 20-60 L/minute in the high-flow interventions and 2 L/minute in the low-flow interventions. The primary outcome was dyspnea numeric rating scale (NRS) "now" where 0 = none and 10 = worst.

RESULTS

Seventeen patients (mean age 51 years, 58% female) completed 55 interventions in a random order. The absolute change of dyspnea NRS between 0 and 10 minutes was -1.8 (SD 1.7) for HFOx, -1.8 (2.0) for HFAir, -0.5 (0.8) for LFOx, and - 0.6 (1.2) for LFAir. In mixed model analysis, HFOx provided greater dyspnea relief than LFOx (mean difference [95% confidence interval] -0.80 [-1.45, -0.15]; p = .02) and LFAir (-1.24 [-1.90, -0.57]; p < .001). HFAir also provided significantly greater dyspnea relief than LFOx (-0.95 [-1.61, -0.30]; p = .005) and LFAir (-1.39 [-2.05, -0.73]; p < .001). HFOx was well tolerated. Seven (54%) patients who tried all interventions blindly preferred HFOx and four (31%) preferred HFAir.

CONCLUSION

We found that HFOx and HFAir provided a rapid and clinically significant reduction of dyspnea at rest in hospitalized nonhypoxemic patients with cancer. Larger studies are needed to confirm these findings (Clinicaltrials.gov: NCT02932332).

IMPLICATIONS FOR PRACTICE

This double-blind, 4×4 crossover trial examined the effect of oxygen or air delivered at high- or low-flow rates on dyspnea in hospitalized nonhypoxemic patients with cancer. High-flow oxygen and high-flow air were significantly better at reducing dyspnea than low-flow oxygen/air, supporting a role for palliation beyond oxygenation.

High-flow nasal cannula oxygen therapy as an emerging option for respiratory failure: the present and the future

Conventional oxygen therapy (COT) and noninvasive ventilation (NIV) have been considered for decades as frontline treatment for acute or chronic respiratory failure. However, COT can be insufficient in severe hypoxaemia whereas NIV, although highly effective, is poorly tolerated by patients and its use requires a specific expertise. High-flow nasal cannula (HFNC) is an emerging technique, designed to provide oxygen at high flows with an optimal degree of heat and humidification, which is well tolerated and easy to use in all clinical settings. Physiologically, HFNC reduces the anatomical dead space and improves carbon dioxide wash-out, reduces the work of breathing, and generates a positive end-expiratory pressure and a constant fraction of inspired oxygen. Clinically, HFNC effectively reduces dyspnoea and improves oxygenation in respiratory failure from a variety of aetiologies, thus avoiding escalation to more invasive supports. In recent years it has been adopted to treat de novo hypoxaemic respiratory failure, exacerbation of chronic obstructive pulmonary disease (COPD), postintubation hypoxaemia and used for palliative respiratory care. While the use of HFNC in acute respiratory failure is now routine as an alternative to COT and sometimes NIV, new potential applications in patients with chronic respiratory diseases (e.g. domiciliary treatment of patients with stable COPD), are currently under evaluation and will become a topic of great interest in the coming years.

Noninvasive approach for de novo acute hypoxemic respiratory failure: noninvasive ventilation, high-flow nasal cannula, both or none?

PURPOSE OF REVIEW

To summarize the recent evidence regarding the use of noninvasive strategies for de novo acute hypoxemic respiratory failure (AHRF).

RECENT FINDINGS

New guidelines for the use of noninvasive ventilation (NIV) in acute respiratory failure have been published. In parallel, high-flow nasal cannula (HFNC) is an emerging noninvasive strategy for AHRF patients. Although some have cautioned against the use of NIV in AHRF, new encouraging data about the use of a helmet interface for NIV in acute respiratory distress syndrome may overcome the limitations of facemask NIV.

SUMMARY

In the last two decades, the use of NIV and HFNC in patients with AHRF has considerably expanded, changing the paradigm of management of AHRF. Choice of each technique should be based according to centre experience and patient tolerability. However, when using noninvasive strategies for AHRF, it is crucial to predefine specific criteria for intubation and monitor patients closely for early detection of clinical deterioration to avoid delayed intubation.

High-Flow Nasal Cannula Oxygen in Patients with Acute Respiratory Failure and Do-Not-Intubate or Do-Not-Resuscitate Orders: A Systematic Review

BACKGROUND AND OBJECTIVES

High-flow nasal cannula (HFNC) oxygen may provide tailored benefits in patients with preset treatment limitations. The objective of this study was to assess the effectiveness of HFNC oxygen in patients with do-not-intubate (DNI) and/or do-not-resuscitate (DNR) orders.

METHODS

We conducted a systematic review of interventional and observational studies. A search was performed using MEDLINE, EMBASE, CINAHL, Scopus, and Web of Science, from inception to October 15, 2018.

RESULTS

We included six studies evaluating 293 patients. All studies had a high risk of bias. The hospital mortality rates of patients with DNI and/or DNR orders receiving HFNC oxygen were variable and ranged from 40% to 87%. In two before and after studies, the initiation of HFNC oxygen was associated with improved oxygenation and reduced respiratory rates. One comparative study found no difference in dyspnea reduction or morphine doses between patients using HFNC oxygen versus conventional oxygen. No studies evaluated quality of life in survivors or quality of death in nonsurvivors. HFNC was generally well tolerated with few adverse events identified.

CONCLUSIONS

While HFNC oxygen remains a viable treatment option for hospitalized patients who have acute respiratory failure and a DNI and/or DNR order, there is a paucity of high-quality, comparative, effectiveness data to guide the usage of HFNC oxygen compared with other treatments, such as noninvasive ventilation, conventional oxygen, and palliative opioids.

Non-invasive Ventilation and CPAP Failure in Children and Indications for Invasive Ventilation

Non-invasive ventilation (NIV) and continuous positive airway pressure (CPAP) are effective treatments for children with severe sleep disordered breathing (SBD). However, some patients may present too severe SDB that do not respond to NIV/CPAP or insufficient compliance to treatment. A careful revaluation of the interface and of ventilator settings should be performed before considering alternative treatments. In patients with obstructive sleep apnea (OSA), alternatives to CPAP/NIV rely on the underlying disease. Ear-nose-throat (ENT) surgery such as adeno-tonsillectomy (AT), turbinectomy or supraglottoplasty represent an effective treatment in selected patients before starting CPAP/NIV and should be reconsidered in case of CPAP failure. Rapid maxillary expansion (RME) is restricted to children with OSA and a narrow palate who have little adenotonsillar tissue, or for those with residual OSA after AT. Weight loss is the first line therapy for obese children with OSA before starting CPAP and should remain a priority in the long-term. Selected patients may benefit from maxillo-facial surgery such as mandibular distraction osteogenesis (MDO) or from neurosurgery procedures like fronto-facial monobloc advancement. Nasopharyngeal airway (NPA) or high flow nasal cannula (HFNC) may constitute efficient alternatives to CPAP in selected patients. Hypoglossal nerve stimulation has been proposed in children with Down syndrome not tolerant to CPAP. Ultimately, tracheostomy represents the unique alternative in case of failure of all the above-mentioned treatments. All these treatments require a multidisciplinary approach with a personalized treatment tailored on the different diseases and sites of obstruction. In patients with neuromuscular, neurological or lung disorders, non-invasive management in case of NIV failure is more challenging. Diaphragmatic pacing has been proposed for some patients with central congenital hypoventilation syndrome (CCHS) or neurological disorders, however its experience in children is limited. Finally, invasive ventilation via tracheotomy represents again the ultimate alternative for children with severe disease and little or no ventilatory autonomy. However, ethical considerations weighting the efficacy against the burden of this treatment should be discussed before choosing this last option.

The Impact of High-Flow Nasal Cannula on the Outcome of Immunocompromised Patients with Acute Respiratory Failure: A Systematic Review and Meta-Analysis

Background and objectives: High-flow nasal cannula (HFNC) can be used as a respiratory support strategy for patients with acute respiratory failure (ARF). However, no clear evidence exists to support or oppose HFNC use in immunocompromised patients. Thus, this meta-analysis aims to assess the effects of HFNC, compared to conventional oxygen therapy (COT) and noninvasive ventilation (NIV), on the outcomes in immunocompromised patients with ARF. The Pubmed, Embase and Cochrane databases were searched up to November 2018. Materials and Methods: Only clinical studies comparing the effect of HFNC with COT or NIV for immunocompromised patients with ARF were included. The outcome included the rate of intubation, mortality and length of stay (LOS). Results: A total of eight studies involving 1433 immunocompromised patients with ARF were enrolled. The pooled analysis showed that HFNC was significantly associated with a reduced intubation rate (risk ratio (RR), 0.83; 95% confidence interval (CI), 0.74-0.94, I2 = 0%). Among subgroup analysis, HFNC was associated with a lower intubation rate than COT (RR, 0.86; 95% CI, 0.75-0.95, I2 = 0%) and NIV (RR, 0.59; 95% CI, 0.40-0.86, I2 = 0%), respectively. However, there was no significant difference between HFNC and control groups in terms of 28-day mortality (RR, 0.78; 95% CI, 0.58-1.04, I2 = 48%), and intensive care unit (ICU) mortality (RR, 0.87; 95% CI, 0.73-1.05, I2 = 57%). The ICU and hospital LOS were similar between HFNC and control groups (ICU LOS: mean difference, 0.49 days; 95% CI, -0.25-1.23, I2 = 69%; hospital LOS: mean difference, -0.12 days; 95% CI, -1.86-1.61, I2 = 64%). Conclusions: Use of HFNC may decrease the intubation rate in immunocompromised patients with ARF compared with the control group, including COT and NIV. However, HFNC could not provide additional survival benefit or shorten the LOS. Further large, randomized controlled trials are needed to confirm these findings.

High Flow Nasal Cannula Oxygen vs. Conventional Oxygen Therapy and Noninvasive Ventilation in Emergency Department Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Acute respiratory failure (ARF) is a common cause of presentation to the Emergency Department (ED). High flow nasal cannula (HFNC) has been introduced as an alternative way to administer oxygen.

OBJECTIVES

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing HFNC with conventional oxygen therapy (COT) and noninvasive ventilation (NIV) exclusively in the ED setting.

METHODS

Inclusion criteria were: RCTs on adults with ARF admitted to the ED, investigating HFNC vs. COT or other modes of ventilation. Trials that compared HFNC support outside the ED, were published as an abstract, or nonrandomized were excluded.

RESULTS

Four RCTs comparing HFNC with COT and one HFNC to NIV met the criteria. Overall, 775 patients were included. The meta-analysis of the studies comparing HFNC and COT showed no differences in intubation requirement, treatment failure, hospitalization, or mortality. Intolerance was significantly higher with HFNC (risk ratio 6.81 95% confidence interval 1.18-39.19; p = 0.03). In the only available RCT comparing HFNC with NIV, no difference was found for intubation rate, treatment failure, tolerance, and dyspnea.

CONCLUSIONS

We did not find any benefit of HFNC compared with COT and NIV in terms of intubation requirement, treatment failure, hospitalization, and mortality; COT was better tolerated.

Effectiveness of high-flow nasal oxygen therapy in management of acute hypoxemic and hypercapnic respiratory failure

Background

High-flow nasal oxygen therapy (HFNOT) therapy has been increasingly used in patients with acute hypoxemic (Type I) respiratory failure (RF). Meanwhile indications and clinical effectiveness of HFNOT in patients with hypercapnic (Type II) RF remain controversial. The aim of our study was to evaluate the outcomes of primary HFTNOT in patients with hypoxemic and hypercapnic RF.

Materials and methods

We conducted a retrospective observational study of patients diagnosed with severe community acquired pneumonia (CAP), who required HFNC oxygen therapy for hypoxemia. Primary end-point was intubation or escalation to NIV rate after HFNOT. The secondary endpoint was the 30-day mortality after an admission regardless of the cause.

Results

Analysis was conducted on all 51 (n = 51) patients. Of these, 32 (63%) were diagnosed with Type I RF and 19 (37%) with Type II RF. The partial pressure of arterial carbon dioxide (PaCO₂) in Type I RF patients was 34.05 mmHg at admission and decreased to 33.07 mmHg after 1 hour of HFNOT. In patients with Type II RF PaCO₂ decreased from 56.47 to 54.97 mmHg. In Type I RF successful outcome was achieved in 25 patients (78%) compared to 11 patients (58%) with Type II RF. Escalation was required in seven patients with Type I RF and eight patients in Type II group. There were no mortalities in our population group.

Conclusions

Our data suggest that HFNOT can be effectively used in Type I and Type II RF. Clinicians should be cautious identifying patients at risk of escalation. A larger population group study is needed to identify predictors of HFNOT failure.

'Rational use of high-flow therapy in infants with bronchiolitis. What do the latest trials tell us?' A Paediatric Research in Emergency Departments International Collaborative perspective

Bronchiolitis is the most common reason for infants to be hospitalised. Over the past decade, the use of high-flow nasal cannulae (HFNC) therapy has increased markedly and it is now utilised not only in the intensive care unit setting but in general paediatric wards and emergency departments. The aim of this systematic review was to summarise and critique the current evidence-base for the use of HFNC in infants with bronchiolitis. We searched Ovid Medline, OvidEmbase, PubMed, Cinahl, Cochrane Library, Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Trials for systematic reviews and randomised controlled trials of HFNC therapy in infants with bronchiolitis from 1 January 2000 to 27 June 2018. We identified four randomised controlled trials (n = 1891) of HFNC in infants with bronchiolitis: three of these studies involved infants treated in emergency departments and inpatient paediatric wards in Spain, Australia and New Zealand, and one study involved infants treated in paediatric intensive care units in France. The findings of this review suggest that HFNC should be used as a rescue treatment for hypoxaemic infants who have not responded to standard sub nasal oxygen therapy. The use of HFNC for work of breathing in the absence of hypoxaemia, and severe disease, is not currently supported by the evidence, and should only be considered in the context of an appropriate research trial.

High-flow nasal cannula for children not compliant with continuous positive airway pressure

OBJECTIVES

Continuous positive airway pressure (CPAP) is an effective treatment of severe obstructive sleep apnea (OSA) but poor compliance is a major limitation. High-flow nasal cannula (HFNC) has been used as an alternative but data about efficacy and objective long-term compliance are scarce; this study aims to address this lack of data.

PATIENTS/METHODS

All consecutive patients, aged 0-18 years, treated with CPAP for a severe OSA defined as an apnea-hypopnea index (AHI) > 10 events/h, and not compliant with home CPAP therapy, defined by a CPAP use of <2 h/night, after at least four weeks from CPAP initiation were considered eligible for the study. HFNC was started during an outpatient visit. Study outcomes were the objective compliance (number of hours use/night) after one month and the improvement of OSA on a respiratory polygraphy (RP) with HFNC.

RESULTS

Eight patients (two boys, mean age 8.9 ± 6.2 years, mean AHI 33 ± 22 events/h) were included in the study: Down syndrome (N = 6), Pierre Robin syndrome (N = 1), Pfeiffer syndrome (N = 1). After one month, five (62%) patients slept with HFNC more than 4 h/night (mean compliance 7 h 10 min ± 0 h 36 min/night). HFNC corrected OSA in the five compliant patients (mean AHI 2 ± 2 events/h with HFNC). HFNC was not accepted by the three oldest patients with Down syndrome.

CONCLUSION

A good compliance as well as a correction of OSA may be obtained with HFNC in selected children with OSA not compliant to CPAP. HFNC may be used as a rescue therapy for children not compliant with CPAP.

[Treatment with high-flow oxygen therapy in asthma exacerbations in a paediatric hospital ward: Experience from 2012 to 2016]

OBJECTIVE

To assess the experience with oxygen therapy with a high flow nasal cannula (HFNC) in hospital on patients with asthmatic exacerbation (AE) in a paediatric ward, and to assess the clinical outcome according with the initial oxygen flow (15lpm or <15lpm).

METHODS

This was a retrospective study of children aged 4 to 15 years with AE admitted to a paediatric ward in a tertiary level hospital between 2012 and 2016. Two groups of patients were compared; Group 1: patients treated with HFNC, and Group 2: patients treated with conventional oxygen therapy. A logistic regression model was constructed in order to identify predictive variables of HFNC. The clinical outcome of the patients was also compared according to the initial flow of HFNC (15lpm VS <15lpm).

RESULTS

The study included a total of 536 patients with AE, 40 (7.5%) of whom required HFNC. The median age was 5 (4-6) years. Heart rate (HR), respiratory rate (RR) and Pulmonary Score (PS) significantly decreased at 3-6hours after starting HFNC in Group 1. In the multivariate analysis, patients with high Pulmonary Score values and greater number of previous admissions required HFNC more frequently. Patients treated with an initial flow of 15lpm were admitted less frequently to the PICU than those with an initial flow less than 15lpm (13% vs 47%, p=.05).

CONCLUSION

HFNC seems to be a useful therapy for asthma exacerbation in paediatric wards. Severity of Pulmonary Score and the number of previous admissions could enable a risk group that needs HFNC to be identified.