High-flow nasal cannula for acute hypoxemic respiratory failure in patients with COVID-19: systematic reviews of effectiveness and its risks of aerosolization, dispersion, and infection transmission

Effectiveness, Adherence and Safety of Home High Flow Nasal Cannula in Chronic Respiratory Disease and Respiratory Insufficiency: A Systematic Review

INTRODUCTION

The effectiveness of home high flow nasal cannula (HFNC) for the treatment of chronic respiratory failure in patients with chronic respiratory diseases (CRDs) has not been summarized. We aimed to conduct a systematic review of the effectiveness, adherence, and safety of HFNC in the long-term treatment of patients with chronic respiratory diseases and respiratory failure.

METHODS

A systematic review was conducted. PubMed, Web of science, and SCOPUS were search up to August 2023. Long-term HFNC studies (≥4 weeks) reporting dyspnea; exacerbations, hospitalizations; peripheral oxygen saturation (SpO2), comfort; patient experience, health-related quality of life or partial pressure of carbon dioxide (paCO2) were included.

RESULTS

Thirteen articles (701 patients) based on 10 studies were selected: randomized control trials (n=3), randomized crossover trials (n=2), crossover (n=3) and retrospective (n=2) studies. COPD (n=6), bronchiectasis (n=2), COPD/bronchiectasis (n=1) and ILD (n=1) were the underlined CRDs. HFNC reduced exacerbations when compared to usual care/home respiratory therapies (n=6). Quality of life outcomes were also in favor of HFNC in patients with COPD and bronchiectasis (n=6). HFNC had significant effects on hospitalizations, paCO2, and lung function. Adherence ranged from 5.2 to 8.6h/day (n=5). Three studies reported no events, 3 non-serious events and 2 no differences compared with other home respiratory therapies.

CONCLUSIONS

HFNC seems more effective than usual care or other home respiratory therapies in reducing exacerbations and improving quality of life in patients with COPD and bronchiectasis, while presenting good adherence and being safe. Its apparently superior effectiveness needs to be better studied in future real-world pragmatic trials.

Implementing High-Flow Nasal Oxygen Therapy in Medical Wards: A Scoping Review to Understand Hospital Protocols and Procedures

Acute hypoxemic respiratory failure (ARF) is a common cause for hospital admission. High-flow nasal oxygen (HFNO) is increasingly used as a first-line treatment for patients with ARF, including in medical wards. Clinical guidance is crucial when providing HFNO, and health services use local health guidance documents (LHGDs) to achieve this. It is unknown what hospital LHGDs recommend regarding ward administration of HFNO. This study examined Australian hospitals' LHGDs regarding ward-based HFNO administration to determine content that may affect safe delivery. A scoping review was undertaken on 2 May 2022 and updated on 29 January 2024 to identify public hospitals' LHGDs regarding delivery of HFNO to adults with ARF in medical wards in two Australian states. Data were extracted and analysed regarding HFNO initiation, monitoring, maintenance and weaning, and management of clinical deterioration. Of the twenty-six included LHGDs, five documents referenced Australian Oxygen Guidelines. Twenty LHGDs did not define a threshold level of hypoxaemia where HFNO use was recommended over conventional oxygen therapy. Thirteen did not provide target oxygen saturation ranges whilst utilising HFNO. Recommendations varied regarding maximal levels of inspired oxygen and flow rates in the medical ward. Eight LHGDs did not specify any system to identify and manage deteriorating patients. Five LHGDs did not provide guidance for weaning patients from HFNO. There was substantial variation in the LHGDs regarding HFNO care for adult patients with ARF in Australian hospitals. These findings have implications for the delivery of high-quality, safe clinical care in hospitals.

Role of Prolonged Intubation in Vocal Fold Motion Impairment in Critically Ill Patients

OBJECTIVE

COVID-19 upsurge in orotracheal intubation (OTI) has opened a new opportunity for studying associated complications. Vocal fold motion impairment (VFMI) is a known complication of OTI. The present study sought to determine the impact of OTI and prolonged OTI on the risk of developing VFMI; to identify both risk and protective factors associated with it.

STUDY DESIGN

Retrospective cohort study.

SETTING

Multicenter.

METHODS

Medical charts were reviewed for all patients that received invasive mechanical ventilation with a subsequent flexible laryngoscopic assessment between March 2020 and March 2022. The main outcomes were the presence of VFMI, including immobility (VFI) and hypomobility (VFH).

RESULTS

A total of 155 patients were included, 119 (76.8%) COVID-19 and 36 (23.2%) non-COVID-19 patients; overall 82 (52.9%) were diagnosed with VFMI. Eighty (52.3%) patients underwent a tracheostomy. The median (IQR) intubation duration was 18 (11-24.25) days, while the median (IQR) time to tracheostomy was 22 (16-29). In the adjusted model, we observed there was a 68% increased risk for VFMI from day 21 of intubation (RR: 1.68; 95% CI 1.07-2.65; P = 0.025).

CONCLUSIONS

VFMI is a frequent complication in severely ill patients that undergo intubation. A prolonged OTI was associated with an increased risk of VFMI, highlighting the importance of timely tracheostomy. Further research is needed to confirm these findings in other subsets of critically ill patients.

An Individual Barrier Enclosure Actively Removing Aerosols for Airborne Isolation: A Vacuum Tent

BACKGROUND

Aerosol barrier enclosure systems have been designed to prevent airborne contamination, but their safety has been questioned. A vacuum tent was designed with active continuous suctioning to minimize risks of aerosol dispersion. We tested its efficacy, risk of rebreathing, and usability on a bench, in healthy volunteers, and in an ergonomic clinical assessment study.

METHODS

First, a manikin with airway connected to a breathing simulator was placed inside the vacuum tent to generate active breathing, cough, and CO2 production; high-flow nasal cannula (HFNC) was applied in the manikin's nares. Negative pressure was applied in the vacuum tent's apex port using wall suction. Fluorescent microparticles were aerosolized in the vacuum tent for qualitative assessment. To quantify particles inside and around vacuum tent (aerosol retention), an airtight aerosol chamber with aerosolized latex microparticles was used. The vacuum tent was tested on healthy volunteers breathing with and without HFNC. Last, its usability was assessed in 5 subjects by 5 different anesthesiologists for delivery of full anesthesia, including intubation and extubation.

RESULTS

The vacuum tent was adjusted until no leak was visualized using fluorescent particles. The efficacy in retaining microparticles was confirmed quantitatively. CO2 accumulation inside the vacuum tent showed an inverse correlation with the suction flow in all conditions (normal breathing and HFNC 30 or 60 L/min) in bench and healthy volunteers. Particle removal efficacy and safe breathing conditions (CO2, temperature) were reached when suctioning was at least 60 L/min or 20 L/min > HFNC flow. Five subjects were successfully intubated and anesthetized without ergonomic difficulties and with minimal interference with workflow and an excellent overall assessment by the anesthesiologists.

CONCLUSIONS

The vacuum tent effectively minimized aerosol dispersion. Its continuous suction system set at a high suction flow was crucial to avoid the spread of aerosol particles and CO2 rebreathing.

Efficacy of a surgical mask during high-flow nasal oxygen therapy in preventing aerosol dispersion: a randomized controlled study

PURPOSE

It is not clear whether or not high-flow nasal oxygenation used in patients with severe respiratory tract infection, or coughing, increases the risk of infection to the healthcare personnel, and whether or not applying a surgical mask to the patient's face or treating the patient in a negative-pressure room can reduce the risk.

METHODS

In a randomized crossover design, we compared in 50 participants receiving high-flow nasal oxygenation, the aerosol counts measured at approximately 20 cm above the participant's mouth in 32 different circumstances (with or without coughing, with or without wearing a surgical mask, at four different flow rates of oxygenation, in a positive- or negative-pressure operating room).

RESULTS

In a positive-pressure room, a surgical mask significantly decreased the aerosol counts during coughing (P = 0.0005), or during no coughing (P = 0.009), under high-flow nasal oxygenation (at 60 l.min-1). In the negative-pressure room, the aerosol count was significantly lower than in the positive-pressure room, for all the circumstances (all P < 0.001), and a surgical mask significantly decreased the aerosol counts during coughing (P = 0.047) but not during no coughing (P = 0.60).

CONCLUSION

In conclusion, treating a patient in a negative-pressure room, or applying a surgical mask, during high-flow nasal oxygenation (with the flow rate of 60 l.min-1) would inhibit, but would not completely prevent, dispersion of aerosols by coughing.

Exhaled patient derived aerosol dispersion during awake tracheal intubation with concurrent high flow nasal therapy

Awake Tracheal Intubation (ATI) can be performed in cases where there is potential for difficult airway management. It is considered an aerosol generating procedure and is a source of concern to healthcare workers due to the risk of transmission of airborne viral infections, such as SARS-CoV-2. At present, there is a lack of data on the quantities, size distributions and spread of aerosol particles generated during such procedures. This was a volunteer observational study which took place in an operating room of a university teaching hospital. Optical particle sizers were used to provide real time aerosol characterisation during a simulated ATI performed with concurrent high-flow nasal oxygen therapy. The particle sizers were positioned at locations that represented the different locations of clinical staff in an operating room during an ATI. The greatest concentration of patient derived aerosol particles was within 0.5-1.0 m of the subject and along their midline, 2242 #/cm3. As the distance, both radial and longitudinal, from the subject increased, the concentration decreased towards ambient levels, 36.9 ± 5.1 #/cm3. Patient derived aerosol particles < 5 µm in diameter remained entrained in the exhaled aerosol plume and fell to the floor or onto the subject. Patient derived particles > 5 µm in diameter broke away from the exhaled plume and spread radially throughout the operating room. Irrespective of distance and ventilation status, full airborne protective equipment should be worn by all staff when ATI is being performed on patients with suspected viral respiratory infections.

Continuous aerosol monitoring and comparison of aerosol exposure based on smoke dispersion distance and concentrations during oxygenation therapy

This study evaluated the aerosol exposure risks while using common noninvasive oxygenation devices. A simulated mannequin was designed to breathe at a minute ventilation of 20 L/min and used the following oxygen-therapy devices: nasal cannula oxygenation (NCO) at 4 and 15 L/min, nonrebreathing mask (NRM) at 15 L/min, simple mask at 6 L/min, combination of NCO at 15 L/min and NRM at 15 L/min, high-flow nasal cannula (HFNC) at 50 L/min, and flush rate NRM. Two-dimension of the dispersion distance and the aerosol concentrations were measured at head, trunk, and foot around the mannequin for over 10 min. HFNC and flush-rate NRM yielded the longest dispersion distance and highest aerosol concentrations over the three sites of the mannequin than the other oxygenation devices and should use with caution. For flow rates of < 15 L/min, oxygenation devices with mask-like effects, such as NRM or NCO with NRM, decreased aerosol dispersion more effectively than NCO alone or a simple mask. In the upright position, the foot area exhibited the highest aerosol concentration regardless of the oxygenation device than the head-trunk areas of the mannequin. Healthcare workers should be alert even at the foot side of the patient while administering oxygenation therapy.

Reliability of the respiratory rate and oxygenation index for successful high-flow nasal cannula support in coronavirus disease pneumonia: a retrospective cohort study

BACKGROUND

High-flow nasal cannula (HFNC) therapy is an important non-invasive respiratory support in acute respiratory failure, including coronavirus disease (COVID-19) pneumonia. Although the respiratory rate and oxygenation (ROX) index is a simple and useful predictor for HFNC failure and mortality, there is limited evidence for its use in patients with COVID-19 pneumonia. We aimed to evaluate the ROX index as a predictor for HFNC failure in patients with COVID-19 pneumonia. We also evaluated the ROX index as a predictor for 28-day mortality.

METHODS

In this single-center, retrospective, cohort study, 248 patients older than 18 years of age with COVID-19 pneumonia received HFNC therapy for acute respiratory failure. The ROX index was evaluated within 4 h from the start of HFNC therapy. Past medical history, laboratory data, and the ROX index were evaluated as predictors for HFNC failure and 28-day mortality.

RESULTS

The ROX index < 4.88 showed a significantly high risk ratio for HFNC failure (2.13 [95% confidence interval [CI]: 1.47 - 3.08], p < 0.001). The ROX index < 4.88 was significantly associated with 28-day mortality (p = 0.049) in patients with COVID-19 pneumonia receiving HFNC therapy. Age, chronic hypertension, high lactate dehydrogenase level, and low ROX index showed significantly high risk ratio for HFNC failure. C-reactive protein level and low ROX index were predictors of 28-day morality.

CONCLUSION

The ROX index is a useful predictor for HFNC success and 28-day mortality in patients with COVID-19 pneumonia receiving HFNC therapy.

TRIAL REGISTRATION

An independent ethics committee approved the study (Research Ethics Review Committee of Kobe City Medical Center General Hospital [number: zn220303; date: February 21, 2022]), which was performed in accordance with the Declaration of Helsinki, Guidelines for Good Clinical Practice.

Comparison of the efficacy and comfort of high-flow nasal cannula with different initial flow settings in patients with acute hypoxemic respiratory failure: a systematic review and network meta-analysis

BACKGROUND

High-flow nasal cannula (HFNC) has been proven effective in improving patients with acute hypoxemic respiratory failure (AHRF), but a discussion of its use for initial flow settings still need to be provided. We aimed to compare the effectiveness and comfort evaluation of HFNC with different initial flow settings in patients with AHRF.

METHODS

Studies published by October 10, 2022, were searched exhaustively in PubMed, Embase, Web of Science, Cochrane Library (CENTRAL), and the China National Knowledge Infrastructure (CNKI) database. Network meta-analysis (NMA) was performed with STATA 17.0 and R software (version 4.2.1). A Bayesian framework was applied for this NMA. Comparisons of competing models based on the deviance information criterion (DIC) were used to select the best model for NMA. The primary outcome is the intubation at day 28. Secondary outcomes included short-term and long-term mortality, comfort score, length of ICU or hospital stay, and 24-h PaO₂/FiO₂.

RESULTS

This NMA included 23 randomized controlled trials (RCTs) with 5774 patients. With NIV as the control, the HFNC_high group was significantly associated with lower intubation rates (odds ratio [OR] 0.72 95% credible interval [CrI] 0.56 to 0.93; moderate quality evidence) and short-term mortality (OR 0.81 95% CrI 0.69 to 0.96; moderate quality evidence). Using HFNC_Moderate (Mod) group (mean difference [MD] - 1.98 95% CrI -3.98 to 0.01; very low quality evidence) as a comparator, the HFNC_Low group had a slight advantage in comfort scores but no statistically significant difference. Of all possible interventions, the HFNC_High group had the highest probability of being the best in reducing intubation rates (73.04%), short-term (82.74%) and long-term mortality (67.08%). While surface under the cumulative ranking curve value (SUCRA) indicated that the HFNC_Low group had the highest probability of being the best in terms of comfort scores.

CONCLUSIONS

The high initial flow settings (50-60 L/min) performed better in decreasing the occurrence of intubation and mortality, albeit with poor comfort scores. Treatment of HFNC for AHRF patients ought to be initiated from moderate flow rates (30-40 L/min), and individualized flow settings can make HFNC more sensible in clinical practice.

Stratifying risk outcomes among adult COVID-19 inpatients with high flow oxygen: The R4 score

BACKGROUND

High flow oxygen therapy (HFO) is a widely used intervention for pulmonary complications. Amid the coronavirus infectious disease 2019 (COVID-19) pandemic, HFO became a popular alternative to conventional oxygen supplementation therapies. Risk stratification tools have been repurposed -and new ones developed- to estimate outcome risks among COVID-19 patients. This study aims to provide a simple risk stratification system to predict invasive mechanical ventilation (IMV) or death among COVID-19 inpatients on HFO.

METHODS

Among 529 adult inpatients with COVID-19 pneumonia, we selected unadjusted clinical risk factors for developing the composite endpoint of IMV or death. The risk for the primary outcome by each category was estimated using a Cox proportional hazards model. Bootstrapping was used to validate the results.

RESULTS

Age above 62, eGFR under 60 ml/min, room air SpO2 ≤89 % upon admission, history of hypertension, history of diabetes, and any comorbidity (cancer, cardiovascular disease, COPD/ asthma, hypothyroidism, or autoimmune disease) were considered for the score. Each of the six criteria scored 1 point. The score was further simplified into 4 categories: 1) 0 criteria, 2) 1 criterion, 3) 2-3 criteria, and 4) ≥4 criteria. Taking the first category as the reference, risk estimates for the primary endpoint were HR; 2.94 [1.67 - 5.26], 4.08 [2.63 - 7.05], and 6.63 [3.74 - 11.77], respectively. In ROC analysis, the AUC for the model was 0.72.

CONCLUSIONS

Our score uses simple criteria to estimate the risk for IMV or death among COVID-19 inpatients with HFO. Higher category reflects consistent increases in risk for the endpoint.

Treatment options for patients with severe COVID-19

The coronavirus disease 2019 (COVID-19) pandemic has affected the world for over 3 years. Treatment options have improved substantially during this period, including antiviral drugs, antibody drugs, immune-based agents, and vaccination. While these improvements have reduced mortality rates in patients with COVID-19, some patients still develop severe illness. In this review, we aimed to provide an overview of treatments for patients with severe COVID-19 from study reports and clinical experience. We discussed the treatments from two perspectives: respiratory care and drug treatments. In the respiratory care section, we discussed the usefulness of high-flow nasal cannula therapy and non-invasive ventilation as an alternative to invasive ventilation. In the drug treatments section, we focused on three classes for severe COVID-19 treatment: antiviral drugs, immune-based agents, and anticoagulation therapy. We did not discuss antibody drugs and vaccination, as they are not used for severe COVID-19 treatment.

Use of high-flow cannula in pediatric patients with respiratory failure: A prospective cohort study in three high-altitude hospitals

Background and Aims

Acute respiratory failure (ARF) is a common cause of morbimortality, and a frequent reason for admission to the pediatric intensive care unit (PICU). It requires a high-flow oxygen device as treatment. Our aim is to determine the frequency and main indications for the use of high-flow nasal cannula (HFNC), and the prevalence of HFNC failure and its main causes, in three hospitals.

Methods

It is a multicenter prospective cohort study, developed in three hospitals in Bogota. Eligible patients were children older than 1 month and younger than 18 years who presented ARF and required management with an HFNC. The study was carried out between April 2020 and December 2021. The follow-up was carried out at 1, 6, and 48 h after starting the management.

Results

Of 685 patients included in the study, 296 developed ARF. The prevalence of patients with ARF who required management with HFNC was 48%. The frequency of the pathologies that cause the ARF was: Bronchiolitis was the most frequent pathology (34.5%), followed by asthmatic crisis (15.5%) and pneumonia (12.7%). The average time of use of HFNC was 81.6 h. Regarding treatment failure with HFNC, 15 patients presented torpid evolution and required invasive mechanical ventilation, with a prevalence of therapeutic failure of the HFNC of 10.6%.

Conclusion

The use of HFNC is more frequent in patients with bronchiolitis, in children under 2 years of age and in males, which is in line with what has been reported in the literature. In addition, the failure rate of HFNC is low (10.6%), and it may be useful in other pathologies besides bronchiolitis, such as asthma, pneumonia, among others. It opens the possibility to continue evaluating the role of HFNC in pediatric pathology in new studies.

High flow nasal oxygen and awake prone positioning - Two allies against COVID-19: A systematic review

INTRODUCTION

Severe acute respiratory distress syndrome coronavirus disease-2 (SARS-CoV-2) can lead to acute hypoxemic respiratory failure (AHRF) with possible multisystemic involvement. Ventilation/perfusion mismatch and shunt increase are critical determinants of hypoxemia. Understanding hypoxemia and the mechanisms involved in its genesis is essential to determine the optimal therapeutic strategy. High flow nasal oxygen (HFNO) and awake prone positioning (APP) in patients with COVID-19 AHRF showed promising benefits. The aim of this systematic review was to depict current situation around the combined use of HFNO and APP in patients with COVID-19 AHRF. Particularly, to investigate and report the pathophysiological rationale for adopting this strategy and to evaluate the (1) criteria for initiation, (2) timing, monitoring and discontinuation, and to assess the (3) impact of HFNO/ APP on outcome.

METHODS

We performed a systematic search collecting the articles present in PubMed, Scopus, EMBASE, and Cochrane databases with the following keywords: COVID-19 pneumonia, high flow nasal oxygen, awake prone position ventilation.

RESULTS

Thirteen studies displayed inclusion criteria and were included, accounting for 1242 patients who received HFNO/ APP. The combination of HFNO/ APP has an encouraging pathophysiological rationale for implementing this technique. The recognition of patients who can benefit from HFNO/ APP is difficult and there are no validated protocols to start, monitoring, and discontinue HFNO/ APP therapy. The most used method to monitor the efficacy and failure of this combined technique are oxygenation indexes, but discontinuation techniques are inconsistently and poorly described limiting possible generatability. Finally, this technique provided no clear benefits on outcome.

CONCLUSIONS

Our systematic search provided positive feedbacks for improving the utilization of this combination technique, although we still need further investigation about methods to guide timing, management, and discontinuation, and to assess the intervention effect on outcome.

Computational optimization of delivery parameters to guide the development of targeted Nasal spray

Airborne transmission by droplets and aerosols is known to play a critical role in the spread of many viruses amongst which are the common flu and the more recent SARS-CoV-2 viruses. In the case of SARS-CoV-2, the nasal cavity not only constitutes an important viral entry point, but also a primary site of infection (Sungnak W. et al. Nat. Med. 26:681-687. https://doi.org/10.1038/s41591-020-0868-6 , 2020).. Although face masks are a well-established preventive measure, development of novel and easy-to-use prophylactic measures would be highly beneficial in fighting viral spread and the subsequent emergence of variants of concern (Tao K. et al. Nat Rev Genet 22:757-773. https://doi.org/10.1038/s41576-021-00408-x , 2021). Our group has been working on optimizing a nasal spray delivery system that deposits particles inside the susceptible regions of the nasal cavity to act as a mechanical barrier to impede viral entry. Here, we identify computationally the delivery parameters that maximize the protection offered by this barrier. We introduce the computational approach and quantify the protection rate obtained as a function of a broad range of delivery parameters. We also introduce a modified design and demonstrate that it significantly improves deposition, thus constituting a viable approach to protect against nasal infection of airborne viruses. We then discuss our findings and the implications of this novel system on the prevention of respiratory diseases and targeted drug delivery.

The effects of high-flow oxygen therapy on mortality in patients with COVID-19

BACKGROUND

High-flow oxygen therapy (HFOT) has been successful in treating acute hypoxic respiratory failure (AHRF) and acute respiratory distress syndrome (ARDS). Successful treatment with noninvasive ventilation and avoidance of mechanical ventilation (MV) has been associated with decreased mortality and positive patient outcomes. It is unclear whether the evidence supports the use of HFOT to treat coronavirus disease 2019 (COVID-19)-induced AHRF and ARDS.

OBJECTIVES

To determine whether the use of HFOT decreases the need for intubation or decreases mortality compared with MV in patients with AHRF due to COVID-19.

DATA SOURCES

A literature search was conducted in March 2022 using CINAHL, Embase, PubMed, and Scopus bibliographic databases. Ten studies comparing HFOT and MV in COVID-19 respiratory failure met inclusion criteria.

CONCLUSIONS

Nine studies found a statistically significant reduction in the need for intubation; eight studies found significantly decreased morality in patients who received HFOT. Study design and methodologies limited the findings.

IMPLICATIONS FOR PRACTICE

Based on the available evidence, the use of HFOT positively affected mortality and incidence of the need for intubation and MV. Further research needs to be conducted before HFOT is adopted as the standard of care for COVID-19-induced AHRF and ARDS. Nurse practitioners should be informed regarding the various respiratory support modalities and evaluate risk versus benefit when caring for patients with COVID-19-induced AHRF and ARDS.

Trends in clinical characteristics and outcomes of all critically ill COVID-19 adult patients hospitalized in France between March 2020 and June 2021: a national database study

INTRODUCTION

Studies regarding coronavirus disease 2019 (COVID-19) were mainly performed in the initial wave, but some small-scale data points to prognostic differences for patients in successive waves. We therefore aimed to study the impact of time on prognosis of ICU-admitted COVID-19 patients.

METHOD

We performed a national retrospective cohort study, including all adult patients hospitalized in French ICUs from March 1, 2020 to June 30, 2021, and identified three surge periods. Primary and secondary outcomes were in-hospital mortality and need for invasive mechanical ventilation, respectively.

RESULTS

105,979 critically ill ICU-admitted COVID-19 patients were allocated to the relevant three surge periods. In-hospital mortality for surges 1, 2, and 3 was, respectively, 24%, 27%, and 24%. Invasive mechanical ventilation was the highest level of respiratory support for 42%, 32%, and 31% (p < 0.001) over the whole period, with a decline in the use of vasopressors over time. Adjusted for age, sex, comorbidities, and modified Simplified Acute Physiology Score II at ICU admission, time period was associated with less invasive mechanical ventilation and a high risk of in-hospital death. Vaccination against COVID-19 was associated with a lower likelihood of invasive mechanical ventilation (adjusted sub-hazard ratio [aSHR] = 0.64 [0.53-0.76]) and intra-hospital death (aSHR = 0.80, [0.68-0.95]).

CONCLUSION

In this large database of ICU patients admitted for COVID-19, we observed a decline in invasive mechanical ventilation, vasopressors, and RRT use over time but a high risk of in-hospital death. Vaccination was identified as protective against the risk of invasive mechanical ventilation and in-hospital death.

Comparison of high-flow nasal cannula and conventional oxygen therapy for high-risk patients during bronchoscopy examination: protocol for a randomized controlled trial

INTRODUCTION

High-flow nasal cannula (HFNC) has been proven to improve oxygenation and avoid intubation in hypoxemic patients. It has also been utilized during endoscopy examination to reduce the incidence of hypoxia. However, little is known about the effects of HFNC versus conventional oxygen therapy (COT) on oxygenation during bronchoscopy examination via nasal route; particularly, no study has compared the use of HFNC with that of COT at similar F_IO₂ for patients who have high-risk factors of desaturation during bronchoscopy examination.

METHODS AND ANALYSIS

This randomized controlled trial will be implemented in four academic centers in China. Patients who have high-risk factors including hypoxemia, hypercapnia, morbid obesity, and narrow airway will be enrolled to use HFNC or COT during bronchoscopy examination. In the HFNC group, the initial gas flow will be set at 50 L/min with a fraction of inspired oxygen (F_IO₂) at 0.45, if the patient tolerates, the flow can be increased to 60L/min at most, while in the COT group, oxygen flow will be set at 6 L/min via a conventional nasal cannula. After 5 min pre-oxygenation, the bronchoscope will be inserted via the nasal route. Vital signs, oxygenation (SpO₂), and transcutaneous CO₂ (PtCO₂) will be continuously monitored. The primary outcome is the incidence of hypoxemia, defined as SpO₂ < 90% for 10 s during bronchoscopy examination, and secondary outcomes include the need for treatment escalation and adverse events.

DISCUSSION

Hypoxia is a common complication of bronchoscopy, our study attempted to demonstrate that HFNC may reduce the probability of hypoxia during bronchoscopy in high-risk patients. The results will be disseminated through peer-reviewed journals and national and international conferences.

TRIAL REGISTRATION

http://www.chictr.org.cn/ : ChiCTR2100055038. Registered on 31 December 2021.

Emergency endotracheal intubation in critically ill patients with COVID-19: management and clinical characteristics

Purposes

SARS-CoV-2 have become widespread worldwide since the outbreak. Respiratory function deteriorates rapidly in critically ill patients infected with SARS-CoV-2. Endotracheal intubation is an indispensable therapeutic measure during the development of the disease. This study was intended to describe the experience of endotracheal intubation from front-line anesthesiologists and clinical prognosis of patients infected with Coronavirus disease-19 (COVID-19).

Methods

Fourteen critical patients infected with COVID-19 who underwent endotracheal intubation were included in this study. We collate and analyze the blood gas results before and after tracheal intubation of patients and clinical prognostic indicators such as length of stay and. mortality. The experience of anesthesiologists who intubated patients has also been recorded in detail.

Results

Patients had a mean time of 10.6 days from initial symptoms to endotracheal intubation. Most intubated patients had one or more underlying conditions: hypertension (8, 57.14%), diabetes (5, 35.71%), and cardiovascular and cerebrovascular diseases (2, 14.29%). The oxygenation index increased significantly after intubation compared with before intubation (148.80 ± 42.25 vs 284.43 ± 60.17 p < 0.001). 85.72% of patients required extra-corporeal membrane oxygenation (ECMO) due to inability to maintain oxygen saturation with standard therapeutic measures. Two patients underwent lung transplantation because their lungs were essentially nonfunctional, and they recovered well after surgery. As of this writing, all patients were discharged after satisfactory recovery.

Conclusions

Reasonable selection of intubation timing is particularly important. It is crucial to increase the patient's oxygen supply and reduce oxygen consumption as much as possible during endotracheal intubation. In addition, the personal protective measures of medical personnel participating in treatment should be scientific and standardized.

Graphical Abstract

The Relationship of Respiratory Rate-Oxygenation (ROX) and Modified ROX Index With High-Flow Nasal Cannula Oxygen Therapy in COVID-19 Patients: An Observational Pilot Study

Background and aim Respiratory Rate-Oxygenation (ROX) and modified ROX (mROX) indexes have been proposed to detect early high-flow nasal cannula (HFNC) therapy failure. We evaluated the utility and relationship of ROX and mROX indexes in COVID-19 patients started on HFNC oxygen therapy. Methods This pilot study collected data from adult COVID-19 patients requiring HFNC oxygenation from 29 Jan - 29 Jun 2021. The patients were divided into two cohorts based on HFNC therapy success. ROX and mROX were compared using statistical diagnostic testing, including receiver operating characteristics and area under the curve (AUC) using online Epitools (https://epitools.ausvet.com.au/) and MedCalc software (MedCalc Software Ltd, Ostend, Belgium, https://www.medcalc.org/); p<0.05 was considered significant. Results Twenty-seven patients fulfilled the inclusion criteria; 48.15% of therapy failed. The cohort's mean ± standard deviation age was 53.93 ± 10.67 years; 74.1% were male. The accuracy of predicting failure for mean ROX versus mROX at baseline and six-hour values was 59.81 versus 70.68 and 67.42 versus 74.88, respectively (all p>0.05). The AUC for ROX and mROX at baseline and at six hours were statistically indifferent. Only an mROX of 4.05 (mean value) and 3.34 (Youden's J cut-off) had a sensitivity plus specificity at 156% and 163%, respectively. Conclusion Both ROX and mROX at baseline and six hours had fair-to-good accuracies and AUC; the differences were insignificant. Both ROX and mROX had better accuracies at six hours. However, only mROX < 4.05 at six hours fulfilled the sensitivity plus specificity criteria to be a clinically valuable screener.

Aerosol release, distribution, and prevention during aerosol therapy: a simulated model for infection control

Aerosol therapy is used to deliver medical therapeutics directly to the airways to treat respiratory conditions. A potential consequence of this form of treatment is the release of fugitive aerosols, both patient derived and medical, into the environment and the subsequent exposure of caregivers and bystanders to potential viral infections. This study examined the release of these fugitive aerosols during a standard aerosol therapy to a simulated adult patient. An aerosol holding chamber and mouthpiece were connected to a representative head model and breathing simulator. A combination of laser and Schlieren imaging was used to non-invasively visualize the release and dispersion of fugitive aerosol particles. Time-varying aerosol particle number concentrations and size distributions were measured with optical particle sizers at clinically relevant positions to the simulated patient. The influence of breathing pattern, normal and distressed, supplemental air flow, at 0.2 and 6 LPM, and the addition of a bacterial filter to the exhalation port of the mouthpiece were assessed. Images showed large quantities of fugitive aerosols emitted from the unfiltered mouthpiece. The images and particle counter data show that the addition of a bacterial filter limited the release of these fugitive aerosols, with the peak fugitive aerosol concentrations decreasing by 47.3-83.3%, depending on distance from the simulated patient. The addition of a bacterial filter to the mouthpiece significantly reduces the levels of fugitive aerosols emitted during a simulated aerosol therapy, p≤ .05, and would greatly aid in reducing healthcare worker and bystander exposure to potentially harmful fugitive aerosols.

High-flow nasal cannula: Evaluation of the perceptions of various performance aspects among Chinese clinical staff and establishment of a multidimensional clinical evaluation system

Objective

In order to facilitate education for clinical users, performance aspects of the high-flow nasal cannula (HFNC) devices were evaluated in the present study. A multidimensional HFNC clinical evaluation system was established accordingly.

Materials and Methods

Clinical staff from Chinese hospitals were invited to participate in an online questionnaire survey. The questionnaire was mainly about the accuracy of temperature, flow rate, and oxygen concentration of HFNC, as well as its humidification capacity. We also investigated how the clinical staff of different professions made decisions on HFNC evaluation indicators. Based on the results of the questionnaire survey of clinicians with rich experience in using HFNC, the relative weights of temperature accuracy, flow velocity accuracy, oxygen concentration accuracy, and humidification ability of HFNC equipment were calculated by the AHP to establish a clinical evaluation system. Four kinds of common HFNC devices were tested and evaluated, and the clinical performance of the four kinds of HFNC devices was evaluated by the new scoring system.

Results

A total of 356 clinicians participated in and completed the questionnaire survey. To ensure the reliability of the HFNC evaluation system, we only adopted the questionnaire results of clinicians with rich experience in using HFNCs. Data from 247 questionnaires (80 doctors, 105 nurses, and 62 respiratory therapists [RTs]) were analyzed. A total of 174 participants used HFNC more than once a week; 88.71% of RTs used HFNC ≥ 1 score daily, 62.86% of nurses used HFNC ≥ 1 score daily, and 66.25% of doctors used HFNC ≥ 1 daily. There was no significant difference in the frequency of use between doctors and nurses. Finally, the relative weights of temperature accuracy (0.088), humidification capacity (0.206), flow velocity accuracy (0.311), and oxygen concentration accuracy (0.395) in the HFNC clinical evaluation system were obtained. The relative weights of clinicians with different occupations and the frequency of HFNC use were obtained. After testing four kinds of HFNC devices through the evaluation system, it was found that the four kinds of HFNC devices have different advantages in different clinical performances, and AiRVO₂ has excellent performance with regard to temperature accuracy and humidification ability. HF-75A and NeoHiF-i7 are good at ensuring the stability of oxygen concentration and the accuracy of the flow velocity of the transported gas, while OH-80S is relatively stable in all aspects.

Conclusion

The clinical evaluation system of HFNC is based on the weight of the experience of clinical personnel with different medical backgrounds. Although the existing practitioners have different educational backgrounds (academic qualifications, majors), our evaluation system can enhance clinical staff’s awareness of HFNC and further optimize the clinical use of HFNC.

Evolution of the Clinical Profile and Outcomes of Unvaccinated Patients Affected by Critical COVID-19 Pneumonia from the Pre-Vaccination to the Post-Vaccination Waves in Italy

The vaccination campaign and the new SARS-CoV-2 variants may have changed the clinical profile and outcomes of patients admitted to sub-intensive unit care. We conducted a retrospective study aimed to compare the clinical and radiological features of unvaccinated critical COVID-19 patients hospitalized during the last pandemic wave (December 2021−February 2022, No-Vax group) and before starting the vaccination campaign (March−December 2020, Pre-Vax group). The No-Vax group was also compared with vaccinated patients of the same pandemic wave (Vax group). With respect to the Pre-Vax group, the No-Vax group contained a higher percentage of smokers (p = 0.0007) and a lower prevalence of males (p = 0.0003). At admission, the No-Vax patients showed both a higher CT score of pneumonia and a worse severe respiratory failure (p < 0.0001). In the No-Vax group, a higher percentage of deaths occurred, though this was not significant. In comparison with the No-Vax group, the Vax patients were older (p = 0.0097), with a higher Charlson comorbidity index (p < 0.0001) and a significantly lower HRCT score (p = 0.0015). The percentage of deaths was not different between the two groups. The No-Vax patients showed a more severe disease in comparison with the Pre-Vax patients, and were younger and had fewer comorbidities than the Vax patients.

A breath of relief: High-flow nasal oxygen in a resource-limited setting

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High-flow nasal oxygen as first-line therapy for COVID-19-associated hypoxemic respiratory failure: a single-centre historical cohort study

PURPOSE

The optimal noninvasive modality for oxygenation support in COVID-19-associated hypoxemic respiratory failure and its association with healthcare worker infection remain uncertain. We report here our experience using high-flow nasal oxygen (HFNO) as the primary support mode for patients with COVID-19 in our institution.

METHODS

We conducted a single-centre historical cohort study of all COVID-19 patients treated with HFNO for at least two hours in our university-affiliated and intensivist-staffed intensive care unit (Jewish General Hospital, Montreal, QC, Canada) between 27 August 2020 and 30 April 2021. We report their clinical characteristics and outcomes. Healthcare workers in our unit cared for these patients in single negative pressure rooms wearing KN95 or fit-tested N95 masks; they underwent mandatory symptomatic screening for COVID-19 infection, as well as a period of asymptomatic screening.

RESULTS

One hundred and forty-two patients were analysed, with a median [interquartile range (IQR)] age of 66 [59-73] yr; 71% were male. Patients had a median [IQR] Sequential Organ Failure Assessment Score of 3 [2-3], median [IQR] oxygen saturation by pulse oximetry/fraction of inspired oxygen ratio of 120 [94-164], and a median [IQR] 4C score (a COVID-19-specific mortality score) of 12 [10-14]. Endotracheal intubation occurred in 48/142 (34%) patients, and overall hospital mortality was 16%. Barotrauma occurred in 21/142 (15%) patients. Among 27 symptomatic and 139 asymptomatic screening tests, there were no cases of HFNO-related COVID-19 transmission to healthcare workers.

CONCLUSION

Our experience indicates that HFNO is an effective first-line therapy for hypoxemic respiratory failure in COVID-19 patients, and can be safely used without significant discernable infection risk to healthcare workers.

The role of procalcitonin in predicting risk of mechanical ventilation and mortality among moderate to severe COVID-19 patients

Background

Serum procalcitonin (PCT) has become an emerging prognostic biomarker of disease progression in patients with COVID-19. This study aims to determine the optimal cut-off value of PCT with regards to important clinical outcomes, especially for mechanical ventilation and all-cause mortality among moderate to severe COVID-19 patients in Malaysia.

Methods

A total of 319 moderate to severe COVID-19 patients hospitalized at the National Referral Hospital in December 2020 were included in the study retrospectively. Demographics, comorbidities, the severity of COVID-19 infection, laboratory and imaging findings, and treatment given were collected from the hospital information system for analysis. The optimal cut-point values for PCT were estimated in two levels. The first level involved 276 patients who had their PCT measured within 5 days following their admission. The second level involved 237 patients who had their PCT measured within 3 days following their admission. Further, a propensity score matching analysis was performed to determine the adjusted relative risk of patients with regards to various clinical outcomes according to the selected cut-point among 237 patients who had their PCT measured within 3 days.

Results

The results showed that a PCT level of 0.2 ng/mL was the optimal cut-point for prognosis especially for mortality outcome and the need for mechanical ventilation. Before matching, patients with PCT ≥ 0.2 ng/mL were associated with significantly higher odds in all investigated outcomes. After matching, patients with PCT > 0.2 ng/mL were associated with higher odds in all-cause mortality (OR: 4.629, 95% CI 1.387–15.449, p = 0.0127) and non-invasive ventilation (OR: 2.667, 95% CI 1.039–6.847, p = 0.0415). Furthermore, patients with higher PCT were associated with significantly longer days of mechanical ventilation (p = 0.0213). There was however no association between higher PCT level and the need for mechanical ventilation (OR: 2.010, 95% CI 0.828–4.878, p = 0.1229).

Conclusion

Our study indicates that a rise in PCT above 0.2 ng/mL is associated with an elevated risk in all-cause mortality, the need for non-invasive ventilation, and a longer duration of mechanical ventilation. The study offers concrete evidence for PCT to be used as a prognostication marker among moderate to severe COVID-19 patients.

Clinical efficacy and safety of high-flow nasal cannula (HFNC) in acute hypoxaemic patients with COVID-19: a protocol for a systematic review and meta-analysis

INTRODUCTION

When COVID-19 patients develop hypoxaemic respiratory failure, they often undergo early intubation. Such a potentially aerosol-generating approach places caregivers at increased risk of contracting COVID-19. This protocol aims to evaluate the clinical efficacy and safety of a high-flow nasal cannula (HFNC) for the treatment of COVID-19 patients with acute hypoxaemic respiratory failure.

METHODS AND ANALYSIS

We intend to search MEDLINE, Embase, Web of Science and Cochrane Library to identify all randomised controlled trials (RCTs) on the use of HFNC in COVID-19 patients with acute respiratory failure. We will screen the RCTs against eligibility criteria for inclusion in our review. Two reviewers will independently undertake RCT selection, data extraction and risk of bias assessment. Primary outcome will be the rate of intubation, and secondary outcomes will be intensive care unit (ICU)/hospital mortality, ICU/hospital length of stay and risks of infection transmission. We will conduct meta-analyses to determine the risk ratio for dichotomous data and the mean difference (MD) or standardised MD for continuous data. Subgroup analyses will be performed based on the different quality of studies, different levels of disease severity, and the age and sex of participants.

ETHICS AND DISSEMINATION

Ethical approval is not required for this study considering this is a systematic review protocol that uses only published data. The findings of this study will be disseminated through peer-reviewed publications and conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42021236519.

Performance Characteristics of a Novel 3D-Printed Bubble Intermittent Mandatory Ventilator (B-IMV) for Adult Pulmonary Support

The COVID-19 pandemic has brought attention to the need for developing effective respiratory support that can be rapidly implemented during critical surge capacity scenarios in healthcare settings. Lung support with bubble continuous positive airway pressure (B-CPAP) is a well-established therapeutic approach for supporting neonatal patients. However, the effectiveness of B-CPAP in larger pediatric and adult patients has not been addressed. Using similar principles of B-CPAP pressure generation, application of intermittent positive pressure inflations above CPAP could support gas exchange and high work of breathing levels in larger patients experiencing more severe forms of respiratory failure. This report describes the design and performance characteristics of the BubbleVent, a novel 3D-printed valve system that combined with commonly found tubes, hoses, and connectors can provide intermittent mandatory ventilation (IMV) suitable for adult mechanical ventilation without direct electrification. Testing of the BubbleVent was performed on a passive adult test lung model and compared with a critical care ventilator commonly used in tertiary care centers. The BubbleVent was shown to deliver stable PIP and PEEP levels, as well as timing control of breath delivery that was comparable with a critical care ventilator.

ASSESSMENT OF PROCEDURAL PAIN IN PATIENTS WITH COVID-19 IN THE INTENSIVE CARE UNIT

Aim

The purpose of the study was to assess the level of procedural pain in patients treated in the COVID-19 intensive care unit, in a tertiary university hospital.

Method

We performed the procedural pain assessment of COVID-19 patients in this study, and 162 (93.6 %) of 173 hospitalized patients assessed during this period. While pain was assessed before, during, and at the 20th minute after endotracheal aspiration, wound care, and position change, which are procedural patient practices, the pain was assessed before, during, and up to the fourth hour after prone positioning, high-flow oxygen therapy (HFOT), and the non-invasive mechanical ventilation (NIMV) procedure. The Numerical Pain Scale was used for conscious patients in pain assessment, while the Behavioral Pain Scale and the Richmond Agitation-Sedation Scale were used for unconscious patients.

Results

Patients who underwent endotracheal aspiration, wound care, and positioning had higher pain levels during procedure than other time points. Patients in the prone position with HFOT and NIMV applied had the highest pain scores at fourth hour after procedure; this increase was statistically significant (p = .000, p < .05).

Conclusions

The study found that COVID-19 patients in the ICU had pain due to procedural practices and that the level of pain during the procedures was higher because endotracheal aspiration, wound care, and positioning were all short-term procedures. Moreover, prone positioning was found to be associated with pressure-related tissue damage, and patients' pain levels increased with the increasing duration of HFOT and NIMV procedure.

SARS-COV-2 - the pandemic of the XXI century, clinical manifestations - neurological implications

In December 2019, in Wuhan, China, the first cases of infection with SARS-CoV 2 responsible for COVID-19 disease were identified. SARS-CoV 2 was declared a pandemic on March 11, 2020, and since then has attracted the medical world's attention. The threat to humans' health that this emerging pandemic could leave raises awareness on the importance of understanding the mechanisms that underlie the developing conditions. The epidemiology, clinical picture, and pathogenesis of COVID-19 show that this virus presents new strategies to overcome the past defensive medicine. While all the current data has focused on the pulmonary and cardiovascular manifestations, little has been written about the neurological implications of the disease. This review updates new clinical aspects that SARS-CoV 2 expresses in humans by focusing primarily on neurological manifestations. The damage to the nervous system became more apparent - anosmia, ageusia, polyneuritis, meningitis, meningoencephalitis, stroke, acute necrotizing encephalopathy. Oxygen therapy is vital for those in critical health situations. Finally, prevention is the most important element in breaking the epidemiological chain.

What can we Learn from Patients who Died from Covid-19 Following Escalation to a Respiratory High Dependency Unit for Trial of Non-Invasive Respiratory Support?

Background: Covid-19 infection is associated with significant risk of death, particularly in older, comorbid patients. Emerging evidence supports use of non-invasive respiratory support (CPAP and high-flow nasal oxygen [HFNO]) in this context, but little is known about its use in patients receiving end-of-life care. Methods: This was a retrospective study of 33 patients who died of Covid-19 on the Respiratory High Dependency Unit at the John Radcliffe Hospital, Oxford between 28/03/20 and 20/05/20. Data was sourced via retrospective review of electronic patient records and drug charts. Results: Patients dying from Covid-19 on the Respiratory HDU were comorbid with median Charlson Comorbidity Index 5 (IQR 4-6); median age 78 (IQR 72-85). Respiratory support was trialled in all but one case with CPAP being the most common form of first line respiratory support (84.8%) however, was only tolerated in 44.8% of patients. Median time to death was 10.7 days from symptom onset (IQR 7.5-14.6) and 4.9 days from hospital admission (IQR 3.1-8.3). 48.5% of patients remained on respiratory support at the time of death. Conclusions: End-of-life care for patients with Covid-19 remains a challenge. Patients tend to be frail and comorbid with a rapid disease trajectory. Non-Invasive Respiratory Support may play a key role in symptom management in select patients, however, further work is needed in order to identify patients who will most benefit from Respiratory Support and those for whom withdrawal may prevent unnecessary distress at the end of life or potential prolongation of suffering.

High-Flow-Sauerstofftherapie – Chancen und Risiken

Mit der High-Flow-Sauerstofftherapie („high flow nasal cannula“ [HFNC]), bei der ein Sauerstoff-Luft-Gasgemisch mit Flüssen zwischen 30 und 70 l/min appliziert wird, steht ein technisch einfaches und hocheffektives Verfahren zur Therapie einer respiratorischen Insuffizienz zur Verfügung. Des Weiteren kann die HFNC während einer Bronchoskopie zur Oxygenierung, vor einer Intubation zur Präoxygenierung und nach Extubation zur Vermeidung einer Re-Intubation verwendet werden. Durch die hohen Gasflüsse wird vermieden, dass der Patient Umgebungsluft inspiriert, sodass eine präzise Einstellung einer inspiratorischen Sauerstofffraktion möglich ist, des Weiteren wird durch einen entstehenden Staudruck ein positiver endexspiratorischer Druck aufgebaut, durch die Anfeuchtung und Erwärmung der Atemluft die mukoziliäre Clearance verbessert sowie die Atemarbeit durch Auswaschen der oberen Atemwege verringert. Im Vergleich zur konventionellen Sauerstofftherapie ist die Aerosolbildung durch eine HFNC nicht erhöht, sodass dieses Verfahren auch bei COVID-19 eingesetzt werden kann. Beim hyperkapnischen Lungenversagen liegen bisher keine konklusiven Daten für die Effekte der HFNC vor, hier sollte bevorzugt eine nichtinvasive Beatmung statt einer HFNC erfolgen. Bei der Anwendung darf nicht vergessen werden, dass die mit HFNC behandelten Patienten kritisch krank sind und daher kontinuierlich überwacht werden müssen. So muss sichergestellt sein, dass jederzeit eine Eskalation z. B. auf eine Intubation und invasive Beatmung erfolgen kann.

High-Flow Nasal Cannula and COVID-19: A Clinical Review

During the coronavirus disease 2019 (COVID-19) pandemic, noninvasive respiratory support has played a central role in managing patients affected by moderate-to-severe acute hypoxemic respiratory failure, despite inadequate scientific evidence to support its usage. High-flow nasal cannula (HFNC) treatment has gained popularity because of its effectiveness in delivering a high fraction of humidified oxygen, which improves ventilatory efficiency and the respiratory pattern, as well as its reported high tolerability, ease of use, and application outside of ICUs. Nevertheless, the risk of infection transmission to health-care workers has raised some concerns about its use in the first wave of the pandemic outbreak, with controversial recommendations provided by different scientific societies. This narrative review provides an overview of the recent evidence on the physiologic rationale, risks, and benefits of using HFNC instead of conventional oxygen therapy and other types of noninvasive respiratory support devices, such as continuous positive airway pressure and noninvasive ventilation in patients affected by COVID-19 pneumonia with associated acute hypoxemic respiratory failure. It also summarizes the available evidence with regard to the clinical use of HFNC during the current pandemic and its reported outcomes, and highlights the risks of bioaerosol dispersion associated with HFNC use.

Effects of race on the outcome of COVID-19 in hospitalized patients

BACKGROUND AND AIMS

Recent reports indicate that African Americans have higher mortality rates from SARS-CoV-2 coronavirus disease 19 (COVID-19) compared to Caucasians, with more marked differences in the Midwest region of the US. This study was performed to study differences in COVID-19 related mortality and hospital length of stay (LOS) between African Americans and Caucasians in Midwest setting, and identify factors associated with mortality and LOS.

METHODS

Data were collected from the electronic health records (EHR) of patients admitted to hospitals in Midwest region of the US. EHR of 471 COVID-19 patients were reviewed.

RESULTS

Approximately 63% were African Americans and 34% Caucasians. One hundred sixteen variables were tested. There was no significant difference in hospital mortality between African Americans and Caucasians (OR 1, 95% CI 0.48-1.94). Older age, Chronic kidney disease, mental status change, mechanical ventilation, vasopressor support, high neutrophil count, elevated AST and ALT, high lung involvement severity score and elevated CRP were associated with mortality in a univariate analysis (P < 0.05). Multivariable modeling indicated that mechanical ventilation was the only factor that predicted mortality (OR 6, 95% CI: 2.94-12.48). The LOS did not differ in African Americans and Caucasians. The use of oxygen via high flow nasal cannula (Survival Estimate 1.6, 95% CI: 1.20-2.26), low estimated glomerular filtration rate (Survival Estimate 1.4, 95% CI: 1.05-1.82) and mechanical ventilation (Survival Estimate 3.5, 95% CI: 2.72-4.37) were predictors of LOS.

CONCLUSION

This study performed in Midwest setting in the US showed that race did not affect in-hospital mortality and LOS. Our analysis demonstrated new predictors of LOS.

High-Flow Nasal Oxygenation and Its Applicability in COVID Patients

High-flow nasal oxygenation (HFNO) is a type of oxygen therapy that provides humidified and heated oxygen through a nasal cannula at much higher flow rates than standard oxygen therapy, while also allowing control over the fraction of inspired oxygen (FIO2). Compared to standard oxygen therapy, it is much more comfortable for the patient and seems to alleviate most of the problems associated with standard oxygen therapy, such as dry nose, dry throat and nasal pain. It also provides a variety of benefits that can reduce the incidence of escalating treatment and initiating mechanical ventilation in COVID patients with acute hypoxemic respiratory failure (AHRF). This article provides an overview of HFNO and its current applications in COVID patients during the pandemic.

Noninvasive ventilation and high-flow nasal cannula in patients with acute hypoxemic respiratory failure by covid-19: a retrospective study of the feasebility, safety and outcomes

BACKGROUND

Noninvasive ventilation (NIV) and High-flow nasal cannula (HFNC) are the main forms of treatment for acute respiratory failure. This study aimed to evaluate the effect, safety, and applicability of the NIV and HFNC in patients with acute hypoxemic respiratory failure (AHRF) caused by COVID-19.

METHODS

In this retrospective study, we monitored the effect of NIV and HFNC on the SpO₂ and respiratory rate before, during, and after treatment, length of stay, rates of endotracheal intubation, and mortality in patients with AHRF caused by COVID-19. Additionally, data regarding RT-PCR from physiotherapists who were directly involved in assisting COVID-19 patients and non-COVID-19.

RESULTS

62.2% of patients were treated with HFNC. ROX index increased during and after NIV and HFNC treatment (P < 0.05). SpO₂ increased during NIV treatment (P < 0.05), but was not maintained after treatment (P = 0.17). In addition, there was no difference in the respiratory rate during or after the NIV (P = 0.95) or HFNC (P = 0.60) treatment. The mortality rate was 35.7% for NIV vs 21.4% for HFNC (P = 0.45), while the total endotracheal intubation rate was 57.1% for NIV vs 69.6% for HFNC (P = 0.49). Two adverse events occurred during treatment with NIV and eight occurred during treatment with HFNC. There was no difference in the physiotherapists who tested positive for SARS-CoV-2 directly involved in assisting COVID-19 patients and non-COVID-19 ones (P = 0.81).

CONCLUSION

The application of NIV and HFNC in the critical care unit is feasible and associated with favorable outcomes. In addition, there was no increase in the infection of physiotherapists with SARS-CoV-2.

High-Flow Nasal Cannula in Transport: Process, Results, and Considerations

Objective

The current coronavirus disease 2019 pandemic has increased interest in the use of high-flow nasal cannula (HFNC) in the transport setting. The purpose of this report was to outline the clinical workflow of using HFNC in transport and the results of a retrospective chart review of patients undergoing interhospital transfer on HFNC.

Methods

We conducted a retrospective chart review of all patient transfers using HFNC between January 2018 and June 2019. The primary data abstracted from patient charts included patient demographics, transport distance, HFNC settings including flow rate in liters per minute and fraction of inspired oxygen (Fio₂), and vital signs.

Results

There was a total of 220 patients, 148 pediatric and 72 adult patients. Both pediatric groups experienced statistically significant reductions in heart rate, systolic blood pressure, and diastolic blood pressure. The most common flow rate for both pediatric groups was 10 L/min and 50 L/min for adults. For pediatrics, the most common settings ranged between 30% and 50% Fio₂, with the most common setting being 30% Fio₂. The adult Fio₂ settings ranged from 30% to 100% Fio₂, with the 2 most common settings being 50% Fio₂ and 80% Fio₂. No patients were intubated during the transport encounter.

Conclusion

Our study provides evidence that HFNC is feasible and tolerated by patients and is an additional option for noninvasive ventilation in transport across the age continuum. Future studies are needed to compare HFNC with other noninvasive modalities that include assessing patient tolerance and comfort as contributing factors and to identify indications and contraindications for use in the transport setting.

Analysis of the influencing factors of the clinical effect of respiratory humidifier in treating AIDS complicated with severe Pneumocystis jiroveci pneumonia

OBJECTIVE

To analyze the factors influencing the clinical effect of using respiratory humidifier in patients with AIDS complicated with severe Pneumocystis jiroveci pneumonia (PCP).

METHODS

According to the treatment results, AIDS patients with severe PCP were divided into two groups, successful group (n=68) and failure group (n=94), to compare the early ventilation changes between the two groups.

RESULTS

The ICU ratio of the successful group was lower than that of the failure group (P<0.05). The respiratory frequency, heart rate, PaO₂, C-reactive protein and SOFA score of the successful group were lower than those in the failure group (P<0.05), while SpO₂, FiO₂, PaO₂/FiO₂, SpO₂/FiO₂, Rox index and IL-10 levels were increased in the successful group (P<0.05). The successful group had higher IL-6 and IL-1β level than that of the failure group. The levels of IL-8 were decreased (P<0.05). The success of respiratory humidifier was negatively correlated with the score of SOFA (P<0.05).

CONCLUSION

The clinical effect of respiratory humidifier in the treatment of AIDS patients with severe PCP was related to PaO₂/FiO₂, PaO₂, ROX index, SOFA score, and IL-6 and IL-8 levels.

Nasal high flow oxygen therapy during acute admissions or periods of worsening symptoms

PURPOSE OF REVIEW

Nasal high flow therapy (NHF) is increasingly used in acute care settings. In this review, we consider recent advances in the utilization of NHF in chronic obstructive pulmonary disease (COPD), terminal cancer and symptom management. Considerations around NHF use during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic are also discussed.

RECENT FINDINGS

NHF enables humidification and high flows to be provided together with titrated, supplemental oxygen therapy. Compared to conventional oxygen therapy, NHF improves respiratory physiology by reducing workload, enhancing muco-ciliary clearance and improving dead space washout. Some studies suggest that early use of NHF in people being cared for in the emergency department leads to lower rates of invasive ventilation and noninvasive ventilation. There is also emerging evidence for NHF use in people with COPD and chronic respiratory failure, and in palliative care. NHF is comfortable, well-tolerated and safe for use in the management of breathlessness in people with cancer. NHF can be delivered by face mask to patients with SARS-CoV-2 infection, to ease the burden on critical care resources.

SUMMARY

The evidence base for NHF is rapidly growing and offers promise in relieving troublesome symptoms and for people receiving palliative care.

Early warning scores to assess the probability of critical illness in patients with COVID-19

OBJECTIVE

Validated clinical risk scores are needed to identify patients with COVID-19 at risk of severe disease and to guide triage decision-making during the COVID-19 pandemic. The objective of the current study was to evaluate the performance of early warning scores (EWS) in the ED when identifying patients with COVID-19 who will require intensive care unit (ICU) admission for high-flow-oxygen usage or mechanical ventilation.

METHODS

Patients with a proven SARS-CoV-2 infection with complete resuscitate orders treated in nine hospitals between 27 February and 30 July 2020 needing hospital admission were included. Primary outcome was the performance of EWS in identifying patients needing ICU admission within 24 hours after ED presentation.

RESULTS

In total, 1501 patients were included. Median age was 71 (range 19-99) years and 60.3% were male. Of all patients, 86.9% were admitted to the general ward and 13.1% to the ICU within 24 hours after ED admission. ICU patients had lower peripheral oxygen saturation (86.7% vs 93.7, p≤0.001) and had a higher body mass index (29.2 vs 27.9 p=0.043) compared with non-ICU patients. National Early Warning Score 2 (NEWS2) ≥ 6 and q-COVID Score were superior to all other studied clinical risk scores in predicting ICU admission with a fair area under the receiver operating characteristics curve of 0.740 (95% CI 0.696 to 0.783) and 0.760 (95% CI 0.712 to 0.800), respectively. NEWS2 ≥6 and q-COVID Score ≥3 discriminated patients admitted to the ICU with a sensitivity of 78.1% and 75.9%, and specificity of 56.3% and 61.8%, respectively.

CONCLUSION

In this multicentre study, the best performing models to predict ICU admittance were the NEWS2 and the Quick COVID-19 Severity Index Score, with fair diagnostic performance. However, due to the moderate performance, these models cannot be clinically used to adequately predict the need for ICU admission within 24 hours in patients with SARS-CoV-2 infection presenting at the ED.

Effect of Intubation Timing on the Outcome of Patients With Severe Respiratory Distress Secondary to COVID-19 Pneumonia

Background

The optimal timing of intubation for critically ill patients with severe respiratory illness remains controversial among healthcare providers. The coronavirus disease 2019 (COVID-19) pandemic has raised even more questions about when to implement this life-saving therapy. While one group of providers prefers early intubation for patients with respiratory distress because these patients may deteriorate rapidly without it, other providers believe that intubation should be delayed or avoided because of its associated risks including worse outcomes.

Research question

Our objective was to assess whether the timing of intubation in patients with severe COVID-19 pneumonia was associated with differences in mortality or other outcomes.

Study design and methods

This was a single-center retrospective observational cohort study. We analyzed outcomes of patients who were intubated secondary to COVID-19 pneumonia between March 13, 2020, and December 12, 2020, at Henry Ford Hospital in Detroit, Michigan. Patients were categorized into two groups: early intubated (intubated within 24 hours of the onset of severe respiratory distress) and late intubated (intubated after 24 hours of the onset of severe respiratory distress). Demographics, comorbidities, respiratory rate oxygenation (ROX) index, sequential organ failure assessment (SOFA) score, and treatment received were compared between groups. The primary outcome was mortality. Secondary outcomes were ventilation time, intensive care unit stay, hospital length of stay, and discharge disposition. Post hoc and Kaplan-Meier survival analyses were performed.

Results

A total of 110 patients were included: 55 early intubated and 55 late intubated. We did not observe a significant difference in overall mortality between the early intubated (43%) and the late intubated groups (53%) (p = 0.34). There was no statistically significant difference in patients' baseline characteristics including SOFA scores (the early intubation group had a mean score of 7.5 compared to 6.7 in the late intubation group). Based on the ROX index, the early intubation group had significantly more patients with a reduced risk of intubation (45%) than the late group (27%) (p = 0.029). The early intubation group was treated with a high-flow nasal cannula at a significantly lower rate (47%) than the late intubation group (83%) (p < 0.001). Significant differences in patient baseline characteristics, treatment received, and other outcomes were not observed. Post hoc analysis adjusting for SOFA score between 0 and 9 revealed significantly higher mortality in the late intubation group (49%) than in the early intubation group (26%) (p = 0.03). Patients in the 0 to 9 SOFA group who were intubated later had 2.7 times the odds of dying during hospital admission compared to patients who were intubated early (CI, 1.09-6.67).

Interpretation

The timing of intubation for patients with severe COVID-19 pneumonia was not significantly associated with overall mortality or other patient outcomes. However, within the subgroup of patients with SOFA scores of 9 or lower at the time of intubation, patients intubated after 24 hours of the onset of respiratory distress had a higher risk of death than those who were intubated within 24 hours of respiratory distress. Thus, patients with COVID-19 pneumonia who are not at a high level of organ dysfunction may benefit from early mechanical ventilation.

Factors associated with mechanical ventilation in SARS-CoV-2 patients treated with high-flow nasal cannula oxygen and outcomes

Five percent of patients infected with SARS‐CoV‐2 require advanced respiratory support. The high‐flow nasal cannula oxygenotherapy (HFNCO) appears to be effective and safe to reduce the need for mechanical ventilation. However, the factors associated with HFNCO failure as well as the outcomes of patients receiving this noninvasive respiratory strategy remain unclear. Thus, we performed this study to determine factors leading to intubation of SARS‐CoV‐2 patients treated with HFNCO and patients’ outcomes. We retrospectively analyzed the medical charts of patients admitted in our ICU center for acute respiratory failure due to SARS‐CoV‐2 infection and who initially benefited from HFNCO, between September 1, 2020, and March 1, 2021. We included all adults patients who received HFNCO and compared two groups: those treated with HFNCO alone and those who failed HFNCO. Patients treated with HFNCO and secondarily limited to the use of mechanical ventilation were excluded from the analysis. Sixty‐nine patients were included, 33 were treated with HFNCO alone and 36 failed HFNCO. We found more patients with shock in the HFNCO failure group (p = 0.001). The mean IGSII score was higher in the HFNCO failure group (p < 0.001). The minimum PaO₂/FiO₂ was lower in the HFNCO failure group (p = 0.024). The length of stay in ICU was higher in the HFNCO failure group (p < 0.001). The mean duration of HFNCO before intubation was 1.77 days. Six‐week mortality was higher in the HFNCO failure group (p = 0.034). Ten patients had a complication during intubation. The HFNCO leads to reduce the intubation rate, the length of stay in ICU, and the mortality. Determining the factors associated with HFNCO failure is important to avoid complications following late intubation.

The use of HFNCO avoided the need for intubation in 47.8% of the cases in our study.

Patients with HFNCO failure have a lower minimal PaO2/FiO2, more shock, an higher IGSII score and a longer length of stay in ICU.

We found greater mortality at six weeks in the HFNCO failure group.

We found an high rate of complications following the intubation.

Reorganizing the respiratory high dependency unit for pandemics

INTRODUCTION

Respiratory high dependency units (RHDUs) set up in European countries in the last decade are based on being a transitional step between the intensive care units (ICUs) and the conventional hospital ward in terms of staffing, level of monitoring, and patients' severity. In the pre-COVID-19 era, its main use has been the treatment of hypercapnic acute-on-chronic respiratory failure with noninvasive respiratory support, and more recently, for hypoxemic acute respiratory failure.

AREAS COVERED

We searched the following databases: MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, limited to the terms: COVID-19 and RHDU, Respiratory Intermediate care Unit, acute respiratory distress syndrome (ARDS), noninvasive ventilation (NIV), high flow nasal cannula (HFNC), prone position, and monitoring. In this review, we summarize RHDU´s dual purpose: on the one hand, to decrease the number of admissions into ICU, and on the other hand, early discharges of patients from ICU with prolonged admissions due to the need of care or laborious weaning from invasive mechanical ventilation. Although this dual purpose of RHDUs has contributed to decrease the overload of the ICUs during the pandemic, the hundreds of patients admitted in hospitals, with approximately 20%-30% needing critical care, has exceeded the forecasts of many hospitals.

EXPERT OPINION

It seems clear that a reorganization and optimization of the care of patients with severe COVID-19 is necessary, minimizing admissions to the ICU and facilitating an early discharge. During the pandemic, several hospitals have spontaneously created new RHDUs or extended preexisting RHDUs or up-graded respiratory wards in order to receive less sick patients requiring lower levels of monitoring and nurse-to-patient ratios. This article reviews under a European expert perspective this topic and proposes an adaptation and optimization of the RHDUs to meet the emergent needs caused by the pandemic emphasizing the role of the expert application of noninvasive respiratory therapies in preventing intubation and ICU access.