High-Flow Oxygen vs Conventional Oxygen and Invasive Mechanical Ventilation and Clinical Recovery in Patients With Severe COVID-19-Reply

Oxygen therapy in acute hypoxemic respiratory failure: guidelines from the SRLF-SFMU consensus conference

INTRODUCTION

Although largely used, the place of oxygen therapy and its devices in patients with acute hypoxemic respiratory failure (ARF) deserves to be clarified. The French Intensive Care Society (Société de Réanimation de Langue Française, SRLF) and the French Emergency Medicine Society (Société Française de Médecine d'Urgence, SFMU) organized a consensus conference on oxygen therapy in ARF (excluding acute cardiogenic pulmonary oedema and hypercapnic exacerbation of chronic obstructive diseases) in December 2023.

METHODS

A committee without any conflict of interest (CoI) with the subject defined 7 generic questions and drew up a list of sub questions according to the population, intervention, comparison and outcomes (PICO) model. An independent work group reviewed the literature using predefined keywords. The quality of the data was assessed using the GRADE methodology. Fifteen experts in the field from both societies proposed their own answers in a public session and answered questions from the jury (a panel of 16 critical-care and emergency medicine physicians, nurses and physiotherapists without any CoI) and the public. The jury then met alone for 48 h to write its recommendations.

RESULTS

The jury provided 22 statements answering 11 questions: in patients with ARF (1) What are the criteria for initiating oxygen therapy? (2) What are the targets of oxygen saturation? (3) What is the role of blood gas analysis? (4) When should an arterial catheter be inserted? (5) Should standard oxygen therapy, high-flow nasal cannula oxygen therapy (HFNC) or continuous positive airway pressure (CPAP) be preferred? (6) What are the indications for non-invasive ventilation (NIV)? (7) What are the indications for invasive mechanical ventilation? (8) Should awake prone position be used? (9) What is the role of physiotherapy? (10) Which criteria necessarily lead to ICU admission? (11) Which oxygenation device should be preferred for patients for whom a do-not-intubate decision has been made?

CONCLUSION

These recommendations should optimize the use of oxygen during ARF.

High-Flow Nasal Oxygen for Severe COVID-19 Pneumonia in Greek Patients: A Prospective Observational Study

INTRODUCTION

High-flow nasal oxygen (HFNO) and prone positioning may improve outcomes of coronavirus disease 2019 (COVID-19) patients treated in the intensive care unit (ICU). The aim of this study was to describe outcomes following the timely application of HFNO and prone positioning in COVID-19 patients treated in a ward setting.

METHODS

The study included 89 prospectively recruited subjects at the COVID-19 ward unit of the University Hospital of Heraklion, Greece, between March and December 2020.

RESULTS

Seventy-four (83%) of the 89 subjects in the study had severe COVID-19. Of those, 33 (45%) required HFNO treatment and prone positioning and 15 (45%) were transferred to the ICU, with 4 of them being intubated. Severe COVID-19 and HFNO needs were associated with an increased pneumonia severity index (PSI) score on admission and a worse PaO2/FiO2 ratio. In multivariate analysis, PSI was the only independent predictor of subsequent HFNO needs (OR=1.022). Overall intubation and mortality rates were 5.6% and 3.4%, respectively.

CONCLUSION

This study shows that for patients with severe COVID-19 hospitalized in medical wards, standard COVID-19 treatment, along with the timely utilization of HFNO and prone positioning, resulted in excellent outcomes with fewer ICU admission rates.

Airway Sequelae After Mechanical Ventilation for COVID-19: Protocol for a Scoping Review

BACKGROUND

The epidemiology, morbidity, and burden of disease related to airway sequelae associated with invasive mechanical ventilation in the context of the COVID-19 pandemic remain unclear.

OBJECTIVE

This scoping review aims to summarize the current knowledge regarding airway sequelae after severe SARS-CoV-2 infection. This knowledge will help guide research endeavors and decision-making in clinical practice.

METHODS

This scoping review will include participants of all genders, and no particular age group who developed post-COVID-19 airway-related complication will be excluded. No exclusion criteria will be applied from country, language, or document type. The information source will include analytical observational studies. Unpublished data will not be completely covered as gray literature will be covered. A total of 2 independent reviewers will participate in the process of screening, selection, and data extraction, and the whole process will be performed blindly. Conflict between the reviewers will be solved through discussion and an additional reviewer. The results will be reported by using descriptive statistics, and information will be displayed on RedCap (Research Electronic Data Capture).

RESULTS

The literature search was conducted in May 2022 in the following databases: PubMed, Embase, SCOPUS, Cochrane Library, as well as LILACS and gray literature to identify observational studies; a total of 738 results were retrieved. The scoping review will be finished by March 2023.

CONCLUSIONS

This scoping review will describe current knowledge on the most frequently encountered laryngeal or tracheal sequelae in patients exposed to mechanical ventilation due to SARS-CoV-2 infection. This scoping review will find the incidence of airway sequelae post COVID-19 and the most common sequelae such as airway granuloma, vocal fold paralysis, and airway stenoses. Future studies should evaluate the incidence of these disorders.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/41811.

Performance of helmet CPAP using different configurations: Turbine-driven ventilators vs Venturi devices

BACKGROUND

Traditionally, Venturi-based flow generators have been preferred over mechanical ventilators to provide continuous positive airway pressure (CPAP) through the helmet (h-CPAP). Recently, modern turbine-driven ventilators (TDVs) showed to be safe and effective in delivering h-CPAP. We aimed to compare the pressure stability during h-CPAP delivered by Venturi devices and TDVs and assess the impact of High Efficiency Particulate Air (HEPA) filters on their performance.

METHODS

We performed a bench study using an artificial lung simulator set in a restrictive respiratory condition, simulating two different levels of patient effort (high and low) with and without the interposition of the HEPA filter. We calculated the average of minimal (Pmin), maximal (Pmax) and mean (Pmean) airway pressure and the time product measured on the airway pressure curve (PTPinsp). We defined the pressure swing (Pswing) as Pmax - Pmin and pressure drop (Pdrop) as End Expiratory Pressure - Pmin.

RESULTS

Pswing across CPAP levels varied widely among all the tested devices. During "low effort", no difference in Pswing and Pdrop was found between Venturi devices and TDVs; during high effort, Pswing (p<0.001) and Pdrop (p<0.001) were significantly higher in TDVs compared to Venturi devices, but the PTPinsp was lower (1.50 SD 0.54 vs 1.67 SD 0.55, p<0.001). HEPA filter addition almost doubled Pswing and PTPinsp (p<0.001) but left unaltered the differences among Venturi and TDVs systems in favor of the latter (p<0.001).

CONCLUSIONS

TDVs performed better than Venturi systems in delivering a stable positive pressure level during h-CPAP in a bench setting.

Outcomes comparison between the first and the subsequent SARS-CoV-2 waves - a systematic review and meta-analysis

Background

In the beginning of the SARS-CoV-2 pandemic, health care professionals dealing with COVID-19 had to rely exclusively on general supportive measures since specific treatments were unknown. The subsequent waves could be faced with new diagnostic and therapeutic tools (e.g., anti-viral medications and vaccines). We performed a meta-analysis and systematic review to compare clinical endpoints between the first and subsequent waves.

Methods

Three databases were assessed. The primary outcome was in-hospital mortality. The secondary outcomes were intensive care unit (ICU) mortality, ICU length of stay (LOS), acute renal failure, extracorporeal membrane oxygenation (ECMO) implantation, mechanical ventilation time, hospital LOS, systemic thromboembolism, myocarditis and ventilator associated pneumonia.

Results

A total of 25 studies with 126,153 patients were included. There was no significant difference for the primary endpoint (OR=0.94, 95% CI 0.83-1.07, p=0.35). The first wave group presented higher rates of ICU LOS (SMD= 0.23, 95% CI 0.11-0.35, p<0.01), acute renal failure (OR=1.71, 95% CI 1.36-2.15, p<0.01) and ECMO implantation (OR=1.64, 95% CI 1.06-2.52, p=0.03). The other endpoints did not show significant differences.

Conclusions

The analysis suggests that the first wave group, when compared with the subsequent waves group, presented higher rates of ICU LOS, acute renal failure and ECMO implantation, without significant difference in in-hospital or ICU mortality, mechanical ventilation time, hospital LOS, systemic thromboembolism, myocarditis or ventilator- associated pneumonia.

Advantages and drawbacks of helmet noninvasive support in acute respiratory failure

INTRODUCTION

Non-invasive ventilation (NIV) represents an effective strategy for managing acute respiratory failure. Facemask NIV is strongly recommended in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) with hypercapnia and acute cardiogenic pulmonary edema (ACPE). Its role in managing acute hypoxemic respiratory failure (AHRF) remains a debated issue. NIV and continuous positive airway pressure (CPAP) delivered through the helmet are recently receiving growing interest for AHRF management.

AREAS COVERED

In this narrative review, we discuss the clinical applications of helmet support compared to the other available noninvasive strategies in the different phenotypes of acute respiratory failure.

EXPERT OPINION

Helmets enable the use of high positive end-expiratory pressure, which may protect from self-inflicted lung injury: in AHRF, the possible superiority of helmet support over other noninvasive strategies in terms of clinical outcome has been hypothesized in a network metanalysis and a randomized trial, but has not been confirmed by other investigations and warrants confirmation. In AECOPD patients, helmet efficacy may be inferior to that of face masks, and its use prompts caution due to the risk of CO₂ rebreathing. Helmet support can be safely applied in hypoxemic patients with ACPE, with no advantages over facemasks.

High-flow nasal oxygen in acute hypoxemic respiratory failure: A narrative review of the evidence before and after the COVID-19 pandemic

High-flow nasal oxygen (HFNO) is a type of non-invasive advanced respiratory support that allows the delivery of high-flow and humidified air through a nasal cannula. It can deliver a higher inspired oxygen fraction than conventional oxygen therapy (COT), improves secretion clearance, has a small positive end-expiratory pressure, and exhibits a washout effect on the upper air space that diminishes dead space ventilation. HFNO has been shown to reduce the work of breathing in acute hypoxemic respiratory failure (AHRF) and has become an interesting option for non-invasive respiratory support. Evidence published before the COVID-19 pandemic suggested a possible reduction of the need for invasive mechanical ventilation compared to COT. The COVID-19 pandemic has resulted in a substantial increase in AHRF worldwide, overwhelming both acute and intensive care unit capacity in most countries. This triggered new trials, adding to the body of evidence on HFNO in AHRF and its possible benefits compared to COT or non-invasive ventilation. We have summarized and discussed this recent evidence to inform the best supportive strategy in AHRF both related and unrelated to COVID-19.

2022 Brazilian Thoracic Association recommendations for long-term home oxygen therapy

Some chronic respiratory diseases can cause hypoxemia and, in such cases, long-term home oxygen therapy (LTOT) is indicated as a treatment option primarily to improve patient quality of life and life expectancy. Home oxygen has been used for more than 70 years, and support for LTOT is based on two studies from the 1980s that demonstrated that oxygen use improves survival in patients with COPD. There is evidence that LTOT has other beneficial effects such as improved cognitive function, improved exercise capacity, and reduced hospitalizations. LTOT is indicated in other respiratory diseases that cause hypoxemia, on the basis of the same criteria as those used for COPD. There has been an increase in the use of LTOT, probably because of increased life expectancy and a higher prevalence of chronic respiratory diseases, as well as greater availability of LTOT in the health care system. The first Brazilian Thoracic Association consensus statement on LTOT was published in 2000. Twenty-two years later, we present this updated version. This document is a nonsystematic review of the literature, conducted by pulmonologists who evaluated scientific evidence and international guidelines on LTOT in the various diseases that cause hypoxemia and in specific situations (i.e., exercise, sleep, and air travel). These recommendations, produced with a view to clinical practice, contain several charts with information on indications for LTOT, oxygen sources, accessories, strategies for improved efficiency and effectiveness, and recommendations for the safe use of LTOT, as well as a LTOT prescribing model.

Comment on Liu et al. Application of High-Flow Nasal Cannula in COVID-19: A Narrative Review. Life 2022, 12, 1419

We read the article "Application of High-Flow Nasal Cannula in COVID-19: A Narrative Review" by Liu and colleagues [...].