Continuous Positive Airway Pressure (CPAP) face-mask ventilation is an easy and cheap option to manage a massive influx of patients presenting acute respiratory failure during the SARS-CoV-2 outbreak: A retrospective cohort study

Symptoms in Patients Receiving Noninvasive Ventilation in the Intensive Care Unit

BACKGROUND

Although a multitude of studies have demonstrated the effectiveness of noninvasive ventilation (NIV) for treatment of respiratory insufficiency, there have been few investigations of patients' experiences while receiving this common treatment. Identification of the presence, intensity, and distress of symptoms during NIV will inform the development and testing of interventions to best manage them and improve patients' intensive care unit (ICU) experiences.

OBJECTIVE

The objectives of this study were (a) to identify the presence, intensity, and distress of symptoms in patients receiving NIV in the ICU using a modified version of the Edmonton Symptom Assessment Scale (MESAS) and (b) to describe the most common and distressing symptoms experienced by patients.

METHODS

A cross-sectional descriptive design was used with a convenience sample of 114 participants enrolled from three ICUs at one Midwestern medical center. Participants were approached if they were English-speaking, were 18 years old or older, and had an active order for NIV; exclusions included use of personal NIV equipment, severe cognitive impairment, or problems communicating. Demographic and clinical data were obtained from the electronic health record. Presence, intensity, and distress of patient-reported symptoms were obtained once using a modified, 11-item version of the MESAS.

RESULTS

The mean age of participants was 68 years old, and 54.4% were male. The primary type of NIV was bi-level positive airway pressure; a nasal/oral mask was most frequently used. The symptoms experienced by most of the participants were thirst, anxiety, tiredness, and restlessness; these symptoms were rated as moderate or severe in both intensity and distress by most participants experiencing the symptoms.

DISCUSSION

Patients in the ICU experience both intense and distressful symptoms that can be severe while undergoing treatment with NIV. Future research is warranted to determine these symptoms' interrelatedness and develop interventions to effectively manage patient-reported symptoms.

Becalm: Intelligent Monitoring of Respiratory Patients

The Becalm project is an open and low-cost solution for the remote monitoring of respiratory support therapies like the ones used in COVID-19 patients. Becalm combines a decision-making system based on Case-Based Reasoning with a low-cost, non-invasive mask that enables the remote monitoring, detection, and explanation of risk situations for respiratory patients. This paper first describes the mask and the sensors that allow remote monitoring. Then, it describes the intelligent decision-making system that detects anomalies and raises early warnings. This detection is based on the comparison of cases that represent patients using a set of static variables plus the dynamic vector of the patient time series from sensors. Finally, personalized visual reports are created to explain the causes of the warning, data patterns, and patient context to the healthcare professional. To evaluate the case-based early-warning system, we use a synthetic data generator that simulates patients' clinical evolution from the physiological features and factors described in healthcare literature. This generation process has been verified with a real dataset and allows the validation of the reasoning system with noisy and incomplete data, threshold values, and life/death situations. The evaluation demonstrates promising results and good accuracy (0.91) for the proposed low-cost solution to monitor respiratory patients.

A new reservoir-based CPAP with low oxygen consumption: the Bag-CPAP

BACKGROUND

Several noninvasive ventilatory supports rely in their design on high oxygen consumption which may precipitate oxygen shortage, as experienced during the COVID-19 pandemic. In this bench-to-bedside study, we assessed the performance of a new continuous positive airway pressure (CPAP) device integrating a large reservoir ("Bag-CPAP") designed to minimize oxygen consumption, and compared it with other CPAP devices.

METHODS

First, a bench study compared the performances of Bag-CPAP and four CPAP devices with an intensive care unit ventilator. Two FiO₂ targets (40-60% and 80-100%) at a predefined positive end expiratory pressure (PEEP) level between 5 and 10 cm H₂O were tested and fraction of inspired oxygen (FiO₂) and oxygen consumption were measured. Device-imposed work of breathing (WOB) was also evaluated. Second, an observational clinical study evaluated the new CPAP in 20 adult patients with acute respiratory failure in two hospitals in France. Actual FiO₂, PEEP, peripheral oxygen saturation, respiratory rate, and dyspnea score were assessed.

RESULTS

All six systems tested in the bench study reached the minimal FiO₂ target of 40% and four reached at least 80% FiO₂ while maintaining PEEP in the predefined range. Device-delivered FiO₂/consumed oxygen ratio was the highest with the new reservoir-based CPAP irrespective of FiO₂ target. WOB induced by the device was higher with Bag-CPAP. In the clinical study, Bag-CPAP was well tolerated and could reach high (> 90%) and moderate (> 50%) FiO₂ with an oxygen flow rate of 15 [15-16] and 8 [7-9] L/min, respectively. Dyspnea score improved significantly after introduction of Bag-CPAP, and SpO₂ increased.

CONCLUSIONS

In vitro, Bag-CPAP exhibited the highest oxygen saving properties albeit had increased WOB. It was well accepted clinically and reduced dyspnea. Bag-CPAP may be useful to treat patients with acute respiratory failure in the field, especially when facing constraints in oxygen delivery.

The plausible effects of wearing face masks on sports performance - A scoping review

Objectives

The objectives of this scoping review are to discuss, firstly, the positive aspects of wearing face masks during training (such as a barrier to COVID-19 transmission, air pollutant exposure, and adding load on respiratory resistance flow); secondly, the negative aspects (adverse effects on body temperature and hypoxia risks); and thirdly, the training responses of wearing face masks on aerobic and anaerobic performance.

News

Besides social distancing and hand hygiene, wearing a face mask is proposed to be the prime advocacy for virus containment. During the period of high risk of contamination, the return to sport guidelines proposed by international and national sport federations included wearing face masks during training sessions. However, it is necessary to discuss the pros and cons of wearing face masks during exercise.

Prospects

Although it was essential to wear a face mask during exercise or sport-specific training, there is conflicting evidence on the implications of the use of face masks on physical, physiological as well as psychological well-being or performance. Based on the conflicting empirical findings and anecdotal evidence, certain recommendations have been made for adequate use of face masks during exercise; both to break the chain of transmission and prevent the physiological compromise expected from wearing face masks during exercise. The present review can help stakeholders balance sport guidelines in the event of a respiratory virus pandemic with athlete safety.

Conclusion

Conflicting evidence of mechanistic links between the dose of exercise and the possible adverse effects associated with exercising with face masks is available. Adequately powered studies with strong methodological quality on appropriate selection of masks and usage based on the intensity, duration, and type of sport, age, and gender is needed now for the stakeholders to make informed decisions with respect to exercising with face masks.

Differences in prophylactic performance across wound dressing types used to protect from device-related pressure ulcers caused by a continuous positive airway pressure mask

Prolonged use of continuous positive airway pressure masks, as often required for non-invasive ventilation, involves a risk for facial tissue breakdown due to the sustained deformations caused by tightening of the stiff mask surfaces to the head and the moist environment. The risk of developing mask-related facial injuries can be reduced through suitable cushioning materials placed at the skin-mask interfaces to spread the localised contact forces and disperse the surface and internal tissue stresses. Using an integrated experimental-computational approach, we compared the biomechanical protective performance of three popular foam-based wound dressings to that of a market-lead hydrocolloid dressing when applied to protect the facial skin under a mask. We measured the compressive stiffness properties of the four commercial dressing types in dry and moist conditions, and then fed those to an anatomically realistic finite element model of an adult male head, with an applied simulated mask. Through this process, we calculated the protective efficacy index of each dressing type, indicating the relative contribution of the specified dressing to alleviating facial soft tissue loads with respect to the no-dressing case. The foam-based dressings generally performed substantially better than the hydrocolloid, but foam dressings were also demonstrated to vary by their protective performance.

Clinical Findings and Outcomes From Subjects With COVID-19 Pneumonia in an Intermediate Respiratory Care Unit

BACKGROUND

Many patients with COVID-19 require respiratory support and close monitoring. Intermediate respiratory care units (IRCU) may be valuable to optimally and adequately implement noninvasive respiratory support (NRS) to decrease clinical failure. We aimed at describing intubation and mortality in a novel facility entirely dedicated to COVID-19 and to establish their outcomes.

METHODS

This was a retrospective, observational study performed at one hospital in Spain. We included consecutive subjects age > 18 y, admitted to IRCU with COVID-19 pneumonia, and requiring NRS between December 2020-September 2021. Data collected included mode and usage of NRS, laboratory findings, endotracheal intubation, and mortality at day 30. A multivariable Cox model was used to assess risk factors associated with clinical failure and mortality.

RESULTS

A total of 1,306 subjects were included; 64.6% were male with mean age of 54.7 y. During the IRCU stay, 345 subjects clinically failed NRS (85.5% intubated; 14.5% died). Cox model showed a higher clinical failure in IRCU upon onset of symptoms and hospitalization was < 10 d (hazard ratio [HR] 1.59 [95% CI 1.24-2.03], P < .001) and PaO2 /FIO2 < 100 mm Hg (HR 1.59 [95% CI 1.27-1.98], P < .001). These variables were not associated with increased 30-d mortality.

CONCLUSIONS

The IRCU was a valuable option to manage subjects with COVID-19 requiring NRS, thus reducing ICU overload. Male sex, gas exchange, and blood chemistry at admission were associated with worse prognosis, whereas older age, gas exchange, and blood chemistry were associated with 30-d mortality. These findings may provide a basis for better understanding outcomes and to improve management of noninvasively ventilated patients with COVID-19.

Detailed Analysis of Primary Non-invasive Respiratory Support and Outcomes of Subjects With COVID-19 Acute Hypoxaemic Respiratory Failure

Background The role of non-invasive (continuous positive airway pressure (CPAP) or Non-invasive ventilation (NIV)) respiratory support (NIRS) as a primary oxygenation strategy for COVID-19 patients with acute severe hypoxic respiratory failure (AHRF), as opposed to invasive mechanical ventilation (invasive-MV), is uncertain. While NIRS may prevent complications related to invasive MV, prolonged NIRS and delays in intubation may lead to adverse outcomes. This study was conducted to assess the role of NIRS in COVID-19 hypoxemic respiratory failure and to explore the variables associated with NRIS failure. Methods This is a single-center, observational study of two distinct waves of severe COVID-19 patients admitted to the ICU. Patients initially managed with non-invasive respiratory support with laboratory-confirmed SARS-CoV-2 in acute hypoxaemic respiratory failure were included. Demographics, comorbidities, admission laboratory variables, and ICU admission scores were extracted from electronic health records. Univariate and multiple logistic regression was used to identify predictive factors for invasive mechanical ventilation. Kaplan-Meier survival curves were used to summarise survival between the ventilatory and time-to-intubation groups. Results There were 291 patients, of which 232 were managed with NIRS as an initial ventilation strategy. There was a high incidence of failure (48.7%). Admission APACHE II score, SOFA score, HACOR score, ROX index, and PaO2/FiO2 were all predictive of NIRS failure. Daily (days 1-4) HACOR scores and ROX index measurements highly predicted NIRS failure. Late NIRS failure (>24 hours) was independently associated with increased mortality (44%). Conclusion NIRS is effective as first-line therapy for COVID-19 patients with AHRF. However, failure, particularly delayed failure, is associated with significant mortality. Early prediction of NIRS failure may prevent adverse outcomes.

Comparison of COVID-19 survival in relation to CPAP length of treatment and by comorbidity and transmission setting (community or hospital acquired) in a medium-sized UK hospital in 2020: a retrospective study

OBJECTIVE

To estimate continuous positive airway pressure (CPAP) length of treatment effect on survival of hospitalised COVID-19 patients in a medium-sized UK Hospital, and how this effect changes according to the patient's comorbidity and COVID-19 route of acquisition (community or nosocomial) during the two waves in 2020.

SETTING

The acute inpatient unit in Wrightington, Wigan and Leigh Teaching Hospitals National Health Service (NHS) Foundation Trust (WWL), a medium-sized NHS Trust in north-west of England.

DESIGN

Retrospective cohort of all confirmed COVID-19 patients admitted in WWL during 2020.

PARTICIPANTS

1830 patients (568 first wave, 1262 s wave) with antigen confirmed COVID-19 disease and severe acute respiratory syndrome admitted between 17 March 2020 (first confirmed COVID-19 case) and 31 December 2020.

OUTCOME MEASURE

COVID-19 survival rate in all patients and survival rate in potentially hospital-acquired COVID-19 (PHA) patients were modelled using a predictor set which include comorbidities (eg, obesity, diabetes, chronic ischaemic heart disease (IHD), chronic kidney disease (CKD), chronic obstructive pulmonary disease (COPD)), wave, age, sex and care home residency, and interventions (remdesivir, dexamethasone, CPAP, intensive care unit (ICU), intubation). Secondary outcome measure was CPAP length, which was modelled using the same predictors of the survival rate.

RESULTS

Mortality rate in the second wave was significantly lower than in the first wave (43.4% vs 28.1%, p<0.001), although for PHA COVID-19 patients mortality did not reduce, remaining at very high levels independently of wave and CPAP length. For all cohort, statistical modelling identified CPAP length (HR 95% CI 0.86 to 0.96) and women (HR 95% CI 0.71 to 0.81) were associated with improved survival, while being older age (HR 95% CI 1.02 to 1.03) admitted from care homes (HR 95% CI 2.22 to 2.39), IHD (HR 95% CI 1.13 to 1.24), CKD (HR 95% CI 1.14 to 1.25), obesity (HR 95% CI 1.18 to 1.28) and COPD-emphysema (HR 95% CI 1.18 to 1.57) were associated with reduced survival. Despite the detrimental effect of comorbidities, patients with CKD (95% CI 16% to 30% improvement in survival), IHD (95% CI 1% to 10% improvement in survival) and asthma (95% CI 8% to 30% improvement in survival) benefitted most from CPAP length, while no significant survival difference was found for obese and patients with diabetes.

CONCLUSIONS

The experience of an Acute Trust during the COVID-19 outbreak of 2020 is documented and indicates the importance of care home and hospitals in disease acquisition. Death rates fell between the first and second wave only for community-acquired COVID-19 patients. The fall was associated to CPAP length, especially for some comorbidities. While uncovering some risk and protective factors of mortality in COVID-19 studies, the study also unravels how little is known about PHA COVID-19 and the interaction between CPAP and some comorbidities.

Oxygen efficient respiratory Aid (OxEraTM) device: A safety study

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Africa is a continent that has many developing countries that have constant strain on their healthcare systems.

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Now with the COVID pandemic, the use of oxygen and need for cost efficient and safe oxygen devices has increased.

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OxEra^TM is an oxygen delivery device that has been designed and developed by a consortium named Umoya for emergency use (approval from SAPHRA) in the COVID 19 pandemic.

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Given the potential for the widespread utilisation of this oxygen device in a resource-limited setting, we performed a clinical assessment safety study.

Background

Severe Coronavirus Disease 2019 (COVID-19) can develop pneumonia with severe complications. The Oxygen Efficient Respiratory Aid (OxEra^TM) device has been granted SAPHRA approval for emergency COVID-19 pandemic use. The device has the potential to be used widely in the healthcare sector due to its efficient oxygen supply and adjustable wall positive expiratory pressure (PEP).

Objectives

We assessed whether the OxEra^TM device was safe to use in a healthy adult volunteer population. Our primary objective was to ensure there was no asphyxiation, as assessed by changes observed from baseline End Tidal Carbon Dioxide (ETCO₂) exceeding 6.3 mmHg and above the 45 mmHg threshold. We also monitored changes in vital organ signs and assessed the pain and comfort of the participant at various intervals with changes in PEPs.

Methods

This was an experimental safety study of the OxEra^TM Device on 30 healthy participants at the ICU training centre of Chris Hani Baragwanath Academic Hospital, Johannesburg, South Africa. Each participant had basic vital-signs, ETCO₂, and Oxygen saturation percentages (SpO₂%) taken at baseline until the end of 2 h. In the first 20 min, the PEP was increased by 5 cmH₂0 until 20 min, then continued for the rest of the time on a PEP of 5 cmH₂0. At each interval, vital signs, subjective comfort, pain, and visual scores were measured.

Results

Thirty healthy participants were enrolled. There was no significant difference in ETCO₂ from baseline until 2 h. No participant experienced an increase in measured ETCO₂ greater than 45 mmHg and no increase in ETCO₂ from baseline was greater than 6.3 mmHg. The median increase in ETCO₂ over the study period was 2 mmHg. There were no significant changes in respiratory rate and blood pressure. The heart rate decreased significantly (73–68 bpm). The VAS and comfort score had a significant increase over the 2 h from baseline of 0–2 at maximum; however, the PAS scores showed no significant increase.

Conclusion

Overall the OxEra^TM device achieved the safety endpoints set out. There was no sign of asphyxiation and there were appropriate physiological responses to changes in PEP once applied. The comfort of the mask did worsen over the 2 h; however, the scores were minimally worse on PEP application but improved once-off PEP. No adverse event was recorded at all.

Clinical update on COVID-19 for the emergency clinician: Airway and resuscitation

INTRODUCTION

Coronavirus disease of 2019 (COVID-19) has resulted in millions of cases worldwide. As the pandemic has progressed, the understanding of this disease has evolved.

OBJECTIVE

This narrative review provides emergency clinicians with a focused update of the resuscitation and airway management of COVID-19.

DISCUSSION

Patients with COVID-19 and septic shock should be resuscitated with buffered/balanced crystalloids. If hypotension is present despite intravenous fluids, vasopressors including norepinephrine should be initiated. Stress dose steroids are recommended for patients with severe or refractory septic shock. Airway management is the mainstay of initial resuscitation in patients with COVID-19. Patients with COVID-19 and ARDS should be managed similarly to those ARDS patients without COVID-19. Clinicians should not delay intubation if indicated. In patients who are more clinically stable, physicians can consider a step-wise approach as patients' oxygenation needs escalate. High-flow nasal cannula (HFNC) and non-invasive positive pressure ventilation (NIPPV) are recommended over elective intubation. Prone positioning, even in awake patients, has been shown to lower intubation rates and improve oxygenation. Strategies consistent with ARDSnet can be implemented in this patient population, with a goal tidal volume of 4-8 mL/kg of predicted body weight and targeted plateau pressures <30 cm H₂O. Limited data support the use of neuromuscular blocking agents (NBMA), recruitment maneuvers, inhaled pulmonary vasodilators, and extracorporeal membrane oxygenation (ECMO).

CONCLUSION

This review presents a concise update of the resuscitation strategies and airway management techniques in patients with COVID-19 for emergency medicine clinicians.

Continuous Positive Airway Pressure in Elderly Patients with Severe COVID-19 Related Respiratory Failure

The elderly population represents a high percentage of patients hospitalized for COVID-19 pneumonia and severe respiratory failure, for whom CPAP may be a treatment option. The aim of this study was to describe the CPAP support modalities and to explore factors associated with CPAP failure. In this retrospective study, 110 consecutive patients aged ≥ 75 years were enrolled. Median frailty score, baseline partial arterial pressure of oxygen to fraction of inspired oxygen ratio (P/F), and respiratory rate (RR) were 5, 108, and 30 cycles/min, respectively. Of the 110 patients that began CPAP treatment, 17 patients died within 72 h from baseline, while in 2 patients, CPAP was withdrawn for clinical improvement. Thus, of the 91 patients still on CPAP at day 3, 67% of them needed continuous CPAP delivery. Patients with RR ≥ 30 and with frailty score ≥ 5 had an odds ratio of continuous CPAP needing of 3 and 4, respectively. Patients unable to tolerate CPAP-free periods demonstrated higher mortality risk as compared to those able to tolerate intermittent CPAP (OR: 6.04, 95% CI 2.38−16.46, p < 0.001). The overall in-hospital mortality was 63.6%. Delirium occurred in 59.1%, with a mortality rate in this subgroup of 83.1%. In a time-varying Cox model, the hazard ratio of death was 2.9 in patients with baseline RR ≥ 30 cycle/min, 2.4 in those with baseline P/F < 100. In the same model, the hazard ratio of death was 20 in patients with delirium and a frailty score < 5 and 8.8 in those without delirium and with frailty ≥ 5, indicating a competitive effect between these two variables on the death risk. Conclusions: Respiratory impairment, frailty, and delirium predict treatment failure, with the latter two factors demonstrating a competitive effect on mortality risk. CPAP support may represent a feasible therapeutic option in elderly patients, although chances of a therapeutic benefit are markedly reduced in case of severe respiratory impairment, very frail baseline condition or delirium occurrence.

Noninvasive Respiratory Assist Devices in the Management of COVID-19-related Hypoxic Respiratory Failure: Pune ISCCM COVID-19 ARDS Study Consortium (PICASo)

Objective

To determine whether high-flow nasal oxygen (HFNO) or noninvasive ventilator (NIV) can avoid invasive mechanical ventilation (IMV) in COVID-19-related acute respiratory distress syndrome (ADRS), and the outcome predictors of these modalities.

Design

Multicenter retrospective study conducted in 12 ICUs in Pune, India.

Patients

Patients with COVID-19 pneumonia who had PaO₂/FiO₂ ratio <150 and were treated with HFNO and/or NIV.

Intervention

HFNO and/or NIV.

Measurements

The primary outcome was to assess the need of IMV. Secondary outcomes were death at Day 28 and mortality rates in different treatment groups.

Main results

Among 1,201 patients who met the inclusion criteria, 35.9% (431/1,201) were treated successfully with HFNO and/or NIV and did not require IMV. About 59.5% (714/1,201) patients needed IMV for the failure of HFNO and/or NIV. About 48.3, 61.6, and 63.6% of patients who were treated with HFNO, NIV, or both, respectively, needed IMV. The need of IMV was significantly lower in the HFNO group (p <0.001). The 28-day mortality was 44.9, 59.9, and 59.6% in the patients treated with HFNO, NIV, or both, respectively (p <0.001). On multivariate regression analysis, presence of any comorbidity, SpO₂ <90%, and presence of nonrespiratory organ dysfunction were independent and significant determinants of mortality (p <0.05).

Conclusions

During COVID-19 pandemic surge, HFNO and/or NIV could successfully avoid IMV in 35.5% individuals with PO₂/FiO₂ ratio <150. Those who needed IMV due to failure of HFNO or NIV had high (87.5%) mortality.

How to cite this article

Jog S, Zirpe K, Dixit S, Godavarthy P, Shahane M, Kadapatti K, et al. Noninvasive Respiratory Assist Devices in the Management of COVID-19-related Hypoxic Respiratory Failure: Pune ISCCM COVID-19 ARDS Study Consortium (PICASo). Indian J Crit Care Med 2022;26(7):791-797.

Development of a Medium Care Unit Using an Inexperienced Respiratory Staff: Lessons Learned during the COVID-19 Pandemic

The different waves of the COVID-19 pandemic caused dramatic issues regarding the organization of care. In this context innovative solutions have to be developed in a timely manner to adapt to the organization of the care. The establishment of middle care (MC) units is a bright example of such an adaptation. A multidisciplinary MC team, including expert and non-expert respiratory health care personnel, was developed and trained to work in a COVID-19 MC unit. Important educational resources were set up to ensure rapid and effective training of the MC team, limiting the admission or delaying transfers to ICU and ensuring optimal management of palliative care. We conducted a retrospective analysis of patient data in the MC unit during the second COVID-19 wave in Belgium. The aim of this study was to demonstrate the feasibility of quickly developing an effective respiratory MC unit mixing respiratory expert and non-expert members from outside ICUs. The establishment of an MC unit during a pandemic is feasible and needed. MC units possibly relieve the pressure exerted on ICUs. A highly trained multidisciplinary team is key to ensuring the success of an MC unit during such kind of a pandemic.

SIMEU position paper on non-invasive respiratory support in COVID-19 pneumonia

The rapid worldwide spread of the Coronavirus disease (COVID-19) crisis has put health systems under pressure to a level never experienced before, putting intensive care units in a position to fail to meet an exponentially growing demand. The main clinical feature of the disease is a progressive arterial hypoxemia which rapidly leads to ARDS which makes the use of intensive care and mechanical ventilation almost inevitable. The difficulty of health systems to guarantee a corresponding supply of resources in intensive care, together with the uncertain results reported in the literature with respect to patients who undergo early conventional ventilation, make the search for alternative methods of oxygenation and ventilation and potentially preventive of the need for tracheal intubation, such as non-invasive respiratory support techniques particularly valuable. In this context, the Emergency Department, located between the area outside the hospital and hospital ward and ICU, assumes the role of a crucial junction, due to the possibility of applying these techniques at a sufficiently early stage and being able to rapidly evaluate their effectiveness. This position paper describes the indications for the use of non-invasive respiratory support techniques in respiratory failure secondary to COVID-19-related pneumonia, formulated by the Non-invasive Ventilation Faculty of the Italian Society of Emergency Medicine (SIMEU) on the base of what is available in the literature and on the authors' direct experience. Rationale, literature, tips & tricks, resources, risks and expected results, and patient interaction will be discussed for each one of the escalating non-invasive respiratory techniques: standard oxygen, HFNCO, CPAP, NIPPV, and awake self-repositioning. The final chapter describes our suggested approach to the failing patient.

Treatment of COVID-19 Acute Respiratory Distress Syndrome With a Tabletop Noninvasive Ventilation Device in a Respiratory Intermediate Care Unit

Objective

To study the outcomes of noninvasive ventilation (NIV) administered through a tabletop device for coronavirus disease 2019 acute respiratory distress syndrome in the respiratory intermediate care unit (RIMCU) at a tertiary care hospital in India.

Patients and Methods

We retrospectively studied a cohort of hospitalized patients deteriorating despite low-flow oxygen support who received protocolized management with positive airway pressure using a tabletop NIV device in the RIMCU as a step-up rescue therapy from July 30, 2020 to November 14, 2020. Treatment was commenced on the continuous positive airway pressure mode up to a pressure of 10 cm of H2O, and if required, inspiratory pressures were added using the bilevel positive air pressure mode. Success was defined as weaning from NIV and stepping down to the ward, and failure was defined as escalation to the intensive care unit, the need for intubation, or death.

Results

In total, 246 patients were treated in the RIMCU during the study period. Of these, 168 received respiratory support via a tabletop NIV device as a step-up rescue therapy. Their mean age was 54 years, and 83% were men. Diabetes mellitus (78%) and hypertension (44%) were the commonest comorbidities. Treatment was successful with tabletop NIV in 77% (129/168) of the patients; of them, 41% (69/168) received treatment with continuous positive airway pressure alone and 36% (60/168) received additional increased inspiratory pressure via the bilevel positive air pressure mode.

Conclusion

Respiratory support using the tabletop NIV device was an effective and economical treatment for coronavirus disease 2019 acute respiratory distress syndrome. Further studies are required to assess the appropriate time of initiation for maximal benefits and judicious utilization of resources.

Use of CPAP Failure Score to Predict the Risk of Helmet-CPAP Support Failure in COVID-19 Patients: A Retrospective Study

(1) Background: the aim of this study was to create a score to predict the incidence of CPAP failure in COVID-19 patients early. (2) Methods: in this retrospective observational study, we included all consecutive adult patients admitted between February and April 2021. The main outcome was the failure of CPAP support (intubation or death). (3) Results: two-hundred and sixty-three COVID-19 patients were managed with CPAP. The population was divided in short-CPAP (CPAP days ≤ 10; 72.6%) and long-CPAP (>10; 27.4%) groups. After balancing the entire population using a stabilized IPTW method, we applied a multivariable logistic regression analysis to identify the risk factors for CPAP failure. We used the identified covariates to create a mathematical model, the CPAP Failure Score (CPAP-FS). The multivariable logistic regression analysis identified four variables: SpO2 (OR = 0.86; p-value = 0.001), P/F ratio (OR = 0.99; p-value = 0.008), the Call Score (OR = 1.44; p-value = 0.02), and a pre-existing chronic lung disease (OR = 3.08; p-value = 0.057). The beta-coefficients obtained were used to develop the CPAP-FS, whose diagnostic ability outperformed other relevant COVID-19-related parameters (AUC = 0.87; p-value < 0.0001). We validated the CPAP-FS using a 10-fold internal cross-validation method which confirmed the observed results (AUCs 0.76−0.80; p-values < 0.0001). (4) Conclusions: the CPAP-FS can early identify COVID-19 patients who are at risk of CPAP failure.

Non-invasive respiratory support in the management of acute COVID-19 pneumonia: considerations for clinical practice and priorities for research

Non-invasive respiratory support (NIRS) has increasingly been used in the management of COVID-19-associated acute respiratory failure, but questions remain about the utility, safety, and outcome benefit of NIRS strategies. We identified two randomised controlled trials and 83 observational studies, compromising 13 931 patients, that examined the effects of NIRS modalities-high-flow nasal oxygen, continuous positive airway pressure, and bilevel positive airway pressure-on patients with COVID-19. Of 5120 patients who were candidates for full treatment escalation, 1880 (37%) progressed to invasive mechanical ventilation and 3658 of 4669 (78%) survived to study end. Survival was 30% among the 1050 patients for whom NIRS was the stated ceiling of treatment. The two randomised controlled trials indicate superiority of non-invasive ventilation over high-flow nasal oxygen in reducing the need for intubation. Reported complication rates were low. Overall, the studies indicate that NIRS in patients with COVID-19 is safe, improves resource utilisation, and might be associated with better outcomes. To guide clinical decision making, prospective, randomised studies are needed to address timing of intervention, optimal use of NIRS modalities-alone or in combination-and validation of tools such as oxygenation indices, response to a trial of NIRS, and inflammatory markers as predictors of treatment success.

Noninvasive respiratory support for acute respiratory failure due to COVID-19

PURPOSE OF REVIEW

Noninvasive respiratory support has been widely applied during the COVID-19 pandemic. We provide a narrative review on the benefits and possible harms of noninvasive respiratory support for COVID-19 respiratory failure.

RECENT FINDINGS

Maintenance of spontaneous breathing by means of noninvasive respiratory support in hypoxemic patients with vigorous spontaneous effort carries the risk of patient self-induced lung injury: the benefit of averting intubation in successful patients should be balanced with the harms of a worse outcome in patients who are intubated after failing a trial of noninvasive support.The risk of noninvasive treatment failure is greater in patients with the most severe oxygenation impairment (PaO2/FiO2 < 200 mmHg).High-flow nasal oxygen (HFNO) is the most widely applied intervention in COVID-19 patients with hypoxemic respiratory failure. Also, noninvasive ventilation (NIV) and continuous positive airway pressure delivered with different interfaces have been used with variable success rates. A single randomized trial showed lower need for intubation in patients receiving helmet NIV with specific settings, compared to HFNO alone.Prone positioning is recommended for moderate-to-severe acute respiratory distress syndrome patients on invasive ventilation. Awake prone position has been frequently applied in COVID-19 patients: one randomized trial showed improved oxygenation and lower intubation rate in patients receiving 6-h sessions of awake prone positioning, as compared to conventional management.

SUMMARY

Noninvasive respiratory support and awake prone position are tools possibly capable of averting endotracheal intubation in COVID-19 patients; carefully monitoring during any treatment is warranted to avoid delays in endotracheal intubation, especially in patients with PaO2/FiO2 < 200 mmHg.

A Novel Ventilator Design for COVID-19 and Resource-Limited Settings

There has existed a severe ventilator deficit in much of the world for many years, due in part to the high cost and complexity of traditional ICU ventilators. This was highlighted and exacerbated by the emergence of the COVID-19 pandemic, during which the increase in ventilator production rapidly overran the global supply chains for components. In response, we propose a new approach to ventilator design that meets the performance requirements for COVID-19 patients, while using components that minimise interference with the existing ventilator supply chains. The majority of current ventilator designs use proportional valves and flow sensors, which remain in short supply over a year into the pandemic. In the proposed design, the core components are on-off valves. Unlike proportional valves, on-off valves are widely available, but accurate control of ventilation using on-off valves is not straightforward. Our proposed solution combines four on-off valves, a two-litre reservoir, an oxygen sensor and two pressure sensors. Benchtop testing of a prototype was performed with a commercially available flow analyser and test lungs. We investigated the accuracy and precision of the prototype using both compressed gas supplies and a portable oxygen concentrator, and demonstrated the long-term durability over 15 days. The precision and accuracy of ventilation parameters were within the ranges specified in international guidelines in all tests. A numerical model of the system was developed and validated against experimental data. The model was used to determine usable ranges of valve flow coefficients to increase supply chain flexibility. This new design provides the performance necessary for the majority of patients that require ventilation. Applications include COVID-19 as well as pneumonia, influenza, and tuberculosis, which remain major causes of mortality in low and middle income countries. The robustness, energy efficiency, ease of maintenance, price and availability of on-off valves are all advantageous over proportional valves. As a result, the proposed ventilator design will cost significantly less to manufacture and maintain than current market designs and has the potential to increase global ventilator availability.

Non-invasive Respiratory Support in COVID-19: A Narrative Review

Acute respiratory failure secondary to COVID-19 pneumonia may require a variety of non-pharmacological strategies in addition to oxygen therapy to avoid endotracheal intubation. The response to all these strategies, which include high nasal flow, continuous positive pressure, non-invasive ventilation, or even prone positioning in awake patients, can be highly variable depending on the predominant phenotypic involvement. Deciding when to replace conventional oxygen therapy with non-invasive respiratory support, which to choose, the role of combined methods, definitions, and attitudes toward treatment failure, and improved case improvement procedures are directly relevant clinical questions for the daily care of critically ill COVID-19 patients. The experience accumulated after more than a year of the pandemic should lead to developing recommendations that give answers to all these questions.

Clinical Management of Adult Patients with COVID-19 Outside Intensive Care Units: Guidelines from the Italian Society of Anti-Infective Therapy (SITA) and the Italian Society of Pulmonology (SIP)

INTRODUCTION

The Italian Society of Anti-Infective Therapy (SITA) and the Italian Society of Pulmonology (SIP) constituted an expert panel for developing evidence-based guidance for the clinical management of adult patients with coronavirus disease 2019 (COVID-19) outside intensive care units.

METHODS

Ten systematic literature searches were performed to answer ten different key questions. The retrieved evidence was graded according to the Grading of Recommendations Assessment, Development, and Evaluation methodology (GRADE).

RESULTS AND CONCLUSION

The literature searches mostly assessed the available evidence on the management of COVID-19 patients in terms of antiviral, anticoagulant, anti-inflammatory, immunomodulatory, and continuous positive airway pressure (CPAP)/non-invasive ventilation (NIV) treatment. Most evidence was deemed as of low certainty, and in some cases, recommendations could not be developed according to the GRADE system (best practice recommendations were provided in similar situations). The use of neutralizing monoclonal antibodies may be considered for outpatients at risk of disease progression. For inpatients, favorable recommendations were provided for anticoagulant prophylaxis and systemic steroids administration, although with low certainty of evidence. Favorable recommendations, with very low/low certainty of evidence, were also provided for, in specific situations, remdesivir, alone or in combination with baricitinib, and tocilizumab. The presence of many best practice recommendations testified to the need for further investigations by means of randomized controlled trials, whenever possible, with some possible future research directions stemming from the results of the ten systematic reviews.

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.

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.

CPAP delivered outside critical care during the second wave of COVID-19: outcomes from a UK respiratory surge unit

BACKGROUND

NHS England recommends non-invasive continuous positive airway pressure (CPAP) as a possible treatment for type 1 respiratory failure associated with COVID-19 pneumonitis, either to avoid intubation or as a ceiling of care. However, data assessing this strategy are sparse, especially for the use of CPAP as a ceiling of care, and particularly when delivered outside of a traditional critical care environment. We describe a cohort of patients from Liverpool, UK, who received CPAP on a dedicated respiratory surge unit at the start of the second wave of the COVID-19 pandemic in UK.

METHODS

Retrospective cohort analysis of consecutive patients receiving CPAP for the treatment of respiratory failure secondary to COVID-19 on the respiratory surge unit at the Royal Liverpool Hospital, Liverpool, UK from 21 September until 30 November 2020.

RESULTS

88 patients were included in the analysis. 56/88 (64%) were deemed suitable for escalation to invasive mechanical ventilation (IMV) and received CPAP as a trial; 32/88 (36%) received CPAP as a ceiling of care. Median age was 63 years (IQR: 56-74) and 58/88 (66%) were men. Median SpO2/FiO2 immediately prior to CPAP initiation was 95 (92-152). Among patients for escalation to IMV, the median time on CPAP was 6 days (IQR 4-7) and survival at day 30 was 84% (47/56) with 14/56 (25%) escalated to IMV. Of those patients for whom CPAP was ceiling of care, the median duration of CPAP was 9 days (IQR 7-11) and 18/32 (56%) survived to day 30. Pulmonary barotrauma occurred in 9% of the cohort. There were no associations found on multivariant analysis that were associated with all-cause 30-day mortality.

CONCLUSIONS

With adequate planning and resource redistribution, CPAP may be delivered effectively outside of a traditional critical care setting for the treatment of respiratory failure due to COVID-19. Clinicians delivering CPAP to patients with COVID-19 pneumonitis should be alert to the dangers of pulmonary barotrauma. Among patients who are for escalation of care, the use of CPAP may avoid the need for IMV in some patients. Our data support the NHS England recommendation to consider CPAP as a ceiling of care.

Noninvasive respiratory support and patient self-inflicted lung injury in COVID-19: a narrative review

COVID-19 pneumonia is associated with hypoxaemic respiratory failure, ranging from mild to severe. Because of the worldwide shortage of ICU beds, a relatively high number of patients with respiratory failure are receiving prolonged noninvasive respiratory support, even when their clinical status would have required invasive mechanical ventilation. There are few experimental and clinical data reporting that vigorous breathing effort during spontaneous ventilation can worsen lung injury and cause a phenomenon that has been termed patient self-inflicted lung injury (P-SILI). The aim of this narrative review is to provide an overview of P-SILI pathophysiology and the role of noninvasive respiratory support in COVID-19 pneumonia. Respiratory mechanics, vascular compromise, viscoelastic properties, lung inhomogeneity, work of breathing, and oesophageal pressure swings are discussed. The concept of P-SILI has been widely investigated in recent years, but controversies persist regarding its mechanisms. To minimise the risk of P-SILI, intensivists should better understand its underlying pathophysiology to optimise the type of noninvasive respiratory support provided to patients with COVID-19 pneumonia, and decide on the optimal timing of intubation for these patients.

The LeVe CPAP System for Oxygen-Efficient CPAP Respiratory Support: Development and Pilot Evaluation

Background: The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has placed a significant demand on healthcare providers (HCPs) to provide respiratory support for patients with moderate to severe symptoms. Continuous Positive Airway Pressure (CPAP) non-invasive ventilation can help patients with moderate symptoms to avoid the need for invasive ventilation in intensive care. However, existing CPAP systems can be complex (and thus expensive) or require high levels of oxygen, limiting their use in resource-stretched environments. Technical Development + Testing: The LeVe ("Light") CPAP system was developed using principles of frugal innovation to produce a solution of low complexity and high resource efficiency. The LeVe system exploits the air flow dynamics of electric fan blowers which are inherently suited to delivery of positive pressure at appropriate flow rates for CPAP. Laboratory evaluation demonstrated that performance of the LeVe system was equivalent to other commercially available systems used to deliver CPAP, achieving a 10 cm H2O target pressure within 2.4% RMS error and 50-70% FiO2 dependent with 10 L/min oxygen from a commercial concentrator. Pilot Evaluation: The LeVe CPAP system was tested to evaluate safety and acceptability in a group of ten healthy volunteers at Mengo Hospital in Kampala, Uganda. The study demonstrated that the system can be used safely without inducing hypoxia or hypercapnia and that its use was well-tolerated by users, with no adverse events reported. Conclusions: To provide respiratory support for the high patient numbers associated with the COVID-19 pandemic, healthcare providers require resource efficient solutions. We have shown that this can be achieved through frugal engineering of a CPAP ventilation system, in a system which is safe for use and well-tolerated in healthy volunteers. This approach may also benefit other respiratory conditions which often go unaddressed in Low and Middle Income Countries (LMICs) for want of context-appropriate technology designed for the limited oxygen resources available.

Feasibility of Noninvasive Positive Pressure Ventilation in the Treatment of Oxygen-Dependent COVID-19 Patients in Peru

Intensive care is expensive, and availability is limited. Low- and middle-income countries in particular have struggled to cope with the large influx of critically ill patients during the COVID-19 pandemic. Noninvasive respiratory support devices delivering continuous positive airways pressure (CPAP) require less resource and staff expertise compared with invasive mechanical ventilators and can be routinely used outside of intensive care units. This study assessed the use of the UCL-Ventura Wayrachi CPAP device in hospitalized patients with COVID-19 in Peru. A secondary analysis of data collected for a feasibility study commissioned by the Peruvian Ministry of Health was conducted. Data were collected from three hospitals, including patient demographics, clinical data, and outcomes. Forty-five patients were enrolled from July 16 to September 1, 2020. Eight patients (18%) were intolerant of the CPAP mask. Of the remainder, 18 (48.7%) improved and were discharged from hospital after 6 days. Eight (21.6%) died while on CPAP and 11 (29.7%) were eventually intubated, of whom two died. In total, 27 (60%) survived to hospital discharge. Participating physicians noted the device was easy to use and provided patient benefit, though voiced concerns about the strain on hospital oxygen supplies. In conclusion, the UCL Ventura Wayrachi CPAP device proved feasible in COVID-19 patients in Peru, and offered a bridging therapy for patients who required a ventilator when none were available.

What makes a hydrogel-based dressing advantageous for the prevention of medical device-related pressure ulcers

The synergistic influences of geometrical, mechanical and thermal mismatches between a skin‐contacting medical device and the skin may cause tissue stress concentrations and sharp temperature gradients, both of which contribute to the risk for medical device‐related pressure ulcers. In this work, we developed an innovative, integrated experimental bioengineering approach encompassing mechanical stiffness, friction and thermal property studies for testing the biomechanical suitability of a hydrogel‐based dressing in prophylaxis of injuries caused by devices. We characterised the viscoelastic stress relaxation of the dressing and determined its long‐term elastic modulus. We further measured the coefficient of friction of the hydrogel‐based dressing at dressing‐device and skin‐dressing interfaces, using a tilting‐table tribometer. Lastly, we measured the thermal conductivity of the dressing, using a heat‐flow meter and infrared thermography‐based method. All measurements considered dry and moist conditions, the latter simulating skin perspiration effects. Our results revealed that the long‐term stiffness and the thermal conductivity of the hydrogel‐based dressing matched the corresponding properties of human skin for both dry and moist conditions. The dressing further demonstrated a relatively high coefficient of friction at its skin‐facing and device‐facing aspects, indicating minimal frictional sliding. All these properties make the above dressing advantageous for prevention of device‐related injuries.

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

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

Role of Non-Invasive Respiratory Supports in COVID-19 Acute Respiratory Failure Patients with Do Not Intubate Orders

The current gold-standard treatment for COVID-19-related hypoxemic respiratory failure is invasive mechanical ventilation. However, do not intubate orders (DNI), prevent the use of this treatment in some cases. The aim of this study was to evaluate if non-invasive ventilatory supports can provide a good therapeutic alternative to invasive ventilation in patients with severe COVID-19 infection and a DNI. Data were collected from four centres in three European countries. Patients with severe COVID-19 infection were included. We emulated a hypothetical target trial in which outcomes were compared in patients with a DNI order treated exclusively by non-invasive respiratory support with patients who could be intubated if necessary. We set up a propensity score and an inverse probability of treatment weighting to remove confounding by indication. Four-hundred patients were included: 270 were eligible for intubation and 130 had a DNI order. The adjusted risk ratio for death among patients eligible for intubation was 0.81 (95% CI 0.46 to 1.42). The median length of stay in acute care for survivors was similar between groups (18 (10-31) vs. (19 (13-23.5); p = 0.76). The use of non-invasive respiratory support is a good compromise for patients with severe COVID-19 and a do not intubate order.

Patient-Self Inflicted Lung Injury: A Practical Review

Patients with severe lung injury usually have a high respiratory drive, resulting in intense inspiratory effort that may even worsen lung damage by several mechanisms gathered under the name “patient-self inflicted lung injury” (P-SILI). Even though no clinical study has yet demonstrated that a ventilatory strategy to limit the risk of P-SILI can improve the outcome, the concept of P-SILI relies on sound physiological reasoning, an accumulation of clinical observations and some consistent experimental data. In this review, we detail the main pathophysiological mechanisms by which the patient’s respiratory effort could become deleterious: excessive transpulmonary pressure resulting in over-distension; inhomogeneous distribution of transpulmonary pressure variations across the lung leading to cyclic opening/closing of nondependent regions and pendelluft phenomenon; increase in the transvascular pressure favoring the aggravation of pulmonary edema. We also describe potentially harmful patient-ventilator interactions. Finally, we discuss in a practical way how to detect in the clinical setting situations at risk for P-SILI and to what extent this recognition can help personalize the treatment strategy.

Mortality and clinical outcomes in patients with COVID-19 pneumonia treated with non-invasive respiratory support: A rapid review

Introduction and aim

Non-invasive ventilation (NIV) and continuous positive airway pressure (CPAP) have been widely employed to treat acute respiratory failure secondary to COVID-19 pneumonia, but their role in terms of efficacy and safety are still debated. The aim of this review was to analyse mortality and intubation rates in COVID-19 patients treated with NIV/CPAP.

Methods

Rapid review methodology was applied to include all the studies published since December-2019 until November-2020 with available data on in-hospital mortality in COVID-19 patients treated with NIV or CPAP.

Results

23 manuscripts were included (4776 patients, 66% males, 46% with hypertension). 46% of patients received non-invasive respiratory support, of which 48.4% with CPAP, 46% with NIV, and 4% with either CPAP or NIV. Non-invasive respiratory support failed in 47.7% of patients, of which 26.5% were intubated and 40.9% died. In-hospital mortality was higher in patients treated with NIV compared with CPAP (35.1% vs. 22.2%). Complications were under-reported, but mostly not related to CPAP/NIV treatment.

Conclusion

CPAP and NIV appear equally and frequently applied in patients with COVID-19 pneumonia, but associated with high mortality. Robust evidence is urgently needed to confirm the clinical efficacy of non-invasive respiratory support in COVID-19-related ARDS.

Bedeutung nicht-invasiver Verfahren in der Therapie des akuten hypoxämischen Versagens bei COVID-19

In der Corona-Pandemie werden zunehmend nicht-invasive Verfahren zur Behandlung des akuten hypoxämischen Versagens bei COVID-19 eingesetzt. Hier stehen mit der HFOT (high-flow oxygen therapy), CPAP (continuous positive airway pressure) und der NIV (non-invasive ventilation) unterschiedliche Verfahren zur Verfügung, die das Ziel einer Intubationsvermeidung verfolgen. Der aktuelle Übersichtsartikel fasst die heterogene Studienlage zusammen. Wesentlich ist die Erkenntnis, dass diese nicht-invasiven Verfahren durchaus auch bei einem schweren, akuten hypoxämischen Versagen erfolgreich sein können und damit die Intubation wie auch Tubus-assoziierte Komplikationen vermeiden können. Demgegenüber bleibt aber ebenso zu betonen, dass die prolongierte unterstützte Spontanatmung ebenfalls zu Komplikationen führt und dass demzufolge insbesondere ein spätes NIV-Versagen mit erheblich verschlechterter Prognose einhergeht, was vor dem Hintergrund weiterhin hoher NIV-Versagensraten in Deutschland bedeutsam ist. Der aktuelle Artikel verweist schließlich auch auf einen Parallelartikel in dieser Ausgabe, der die medial in der Öffentlichkeit in Deutschland geführte Debatte zu diesem Thema aufgreift und deren inhaltliche Fragwürdigkeit, aber auch die negativen Auswirkungen auf die Gesellschaft und die Fachwelt adressiert. Gleichzeitig wird die Bedeutung von regelmäßig zu überarbeitenden Leitlinien untermauert.

COVID-19 and acute respiratory failure treated with CPAP

Introduction: Patients admitted with COVID-19 often have severe hypoxemic respiratory insufficiency and it can be difficult to maintain adequate oxygenation with oxygen supplementation alone. There is a physiological rationale for the use of Continuous Positive Airway Pressure (CPAP), and CPAP could keep some patients off mechanical ventilation. We aimed to examine the physiological response to CPAP and the outcome of this treatment. Methods: Data from all patients admitted with COVID-19 and treated with CPAP, from March to July 2020 were collected retrospectively. CPAP was initiated on a medical ward when oxygen supplementation exceeded 10 liters/min to maintain oxygen saturation (SpO2) ≥92%. CPAP was administered with full face masks on a continuous basis until stable improvement in oxygenation or until intubation or death. Results: CPAP was initiated in 53 patients (35 men, 18 women) with a median (IQR) age of 68 (57-78) years. Nine patients were not able to tolerate the CPAP treatment. Median duration for the 44 patients receiving CPAP was 3 (2-6) days. The PaO2/FiO2 ratio was severely reduced to an average of 101 mmHg at initiation of treatment. A positive response of CPAP was seen on respiratory rate (p = 0.002) and on oxygenation (p < 0.001). Of the 44 patients receiving CPAP, 12 (27%) avoided intubation,13 (29%) were intubated, and 19 (43%) died. Of the patients with a ceiling of treatment in the ward (26 of 53) only 2 survived. Older age and high initial oxygen demand predicted treatment failure. Discussion: CPAP seems to have positive effect on oxygenation and respiratory rate in most patients with severe respiratory failure caused by COVID-19. Treatment with CPAP to severely hypoxemic patients in a medical ward is possible, but the prognosis for especially elderly patients with high oxygen requirement and with a ceiling of treatment in the ward is poor.

Management of hospitalised adults with coronavirus disease 2019 (COVID-19): a European Respiratory Society living guideline

INTRODUCTION

Hospitalised patients with coronavirus disease 2019 (COVID-19) as a result of SARS-CoV-2 infection have a high mortality rate and frequently require noninvasive respiratory support or invasive ventilation. Optimising and standardising management through evidence-based guidelines may improve quality of care and therefore patient outcomes.

METHODS

A task force from the European Respiratory Society and endorsed by the Chinese Thoracic Society identified priority interventions (pharmacological and non-pharmacological) for the initial version of this "living guideline" using the PICO (population, intervention, comparator, outcome) format. The GRADE approach was used for assessing the quality of evidence and strength of recommendations. Systematic literature reviews were performed, and data pooled by meta-analysis where possible. Evidence tables were presented and evidence to decision frameworks were used to formulate recommendations.

RESULTS

Based on the available evidence at the time of guideline development (20 February, 2021), the panel makes a strong recommendation in favour of the use of systemic corticosteroids in patients requiring supplementary oxygen or ventilatory support, and for the use of anticoagulation in hospitalised patients. The panel makes a conditional recommendation for interleukin (IL)-6 receptor antagonist monoclonal antibody treatment and high-flow nasal oxygen or continuous positive airway pressure in patients with hypoxaemic respiratory failure. The panel make strong recommendations against the use of hydroxychloroquine and lopinavir-ritonavir. Conditional recommendations are made against the use of azithromycin, hydroxychloroquine combined with azithromycin, colchicine, and remdesivir, in the latter case specifically in patients requiring invasive mechanical ventilation. No recommendation was made for remdesivir in patients requiring supplemental oxygen. Further recommendations for research are made.

CONCLUSION

The evidence base for management of COVID-19 now supports strong recommendations in favour and against specific interventions. These guidelines will be regularly updated as further evidence becomes available.

Non-invasive respiratory support in the treatment of acute hypoxemic respiratory failure secondary to CoViD-19 related pneumonia

In the last 11 months, the SARS-CoV-2 pandemic has overwhelmed and disrupted the whole world in health, social and economic terms. We are progressively learning more and more about the epidemiological and clinical features that distinguish CoViD-19 from any previous experience in the emergency and critical care setting. Experiences are multiplying with regard to the use of non-invasive respiratory support techniques in the context of acute hypoxemic respiratory failure secondary to CoViD-19-related pneumonia. Doubts still far outweigh certainties, but a growing series of mostly monocentric and retrospective studies are becoming available as concrete decision-making and operational support for healthcare workers. In this review the available studies and experiences about non-invasive respiratory support in the treatment of Covid-19 related respiratory failure, mainly coming from outside the ICU setting, will be discussed.

Continuous positive airway pressure for respiratory support during COVID-19 pandemic: a frugal approach from bench to bedside

BACKGROUND

We describe a frugal approach (focusing on needs, performance, and costs) to manage a massive influx of COVID-19 patients with acute hypoxemic respiratory failure (AHRF) using the Boussignac valve protected by a filter ("Filter Frugal CPAP", FF-CPAP) in and out the ICU.

METHODS

(1) A bench study measured the impact of two filters with different mechanical properties on CPAP performances, and pressures were also measured in patients. (2) Non-ICU healthcare staff working in COVID-19 intermediate care units were trained with a video tutorial posted on a massive open online course. (3) A clinical study assessed the feasibility and safety of using FF-CPAP to maintain oxygenation and manage patients out of the ICU during a massive outbreak.

RESULTS

Bench assessments showed that adding a filter did not affect the effective pressure delivered to the patient. The resistive load induced by the filter variably increased the simulated patient's work of breathing (6-34%) needed to sustain the tidal volume, depending on the filter's resistance, respiratory mechanics and basal inspiratory effort. In patients, FF-CPAP achieved pressures similar to those obtained on the bench. The massive training tool provided precious information on the use of Boussignac FF-CPAP on COVID-19 patients. Then 85 COVID-19 patients with ICU admission criteria over a 1-month period were studied upon FF-CPAP initiation for AHRF. FF-CPAP significantly decreased respiratory rate and increased SpO₂. Thirty-six (43%) patients presented with respiratory indications for intubation prior to FF-CPAP initiation, and 13 (36%) of them improved without intubation. Overall, 31 patients (36%) improved with FF-CPAP alone and 17 patients (20%) did not require ICU admission. Patients with a respiratory rate > 32 breaths/min upon FF-CPAP initiation had a higher cumulative probability of intubation (p < 0.001 by log-rank test).

CONCLUSION

Adding a filter to the Boussignac valve does not affect the delivered pressure but may variably increase the resistive load depending on the filter used. Clinical assessment suggests that FF-CPAP is a frugal solution to provide a ventilatory support and improve oxygenation to numerous patients suffering from AHRF in the context of a massive outbreak.

[S2k Guideline - Recommendations for Inpatient Therapy of Patients with COVID-19]

Since December 2019, the novel coronavirus SARS-CoV-2 (Severe Acute Respiratory Syndrome - Corona Virus-2) has been spreading rapidly in the sense of a global pandemic. This poses significant challenges for clinicians and hospitals and is placing unprecedented strain on the healthcare systems of many countries. The majority of patients with Coronavirus Disease 2019 (COVID-19) present with only mild symptoms such as cough and fever. However, about 6 % require hospitalization. Early clarification of whether inpatient and, if necessary, intensive care treatment is medically appropriate and desired by the patient is of particular importance in the pandemic. Acute hypoxemic respiratory insufficiency with dyspnea and high respiratory rate (> 30/min) usually leads to admission to the intensive care unit. Often, bilateral pulmonary infiltrates/consolidations or even pulmonary emboli are already found on imaging. As the disease progresses, some of these patients develop acute respiratory distress syndrome (ARDS). Mortality reduction of available drug therapy in severe COVID-19 disease has only been demonstrated for dexamethasone in randomized controlled trials. The main goal of supportive therapy is to ensure adequate oxygenation. In this regard, invasive ventilation and repeated prone positioning are important elements in the treatment of severely hypoxemic COVID-19 patients. Strict adherence to basic hygiene, including hand hygiene, and the correct wearing of adequate personal protective equipment are essential when handling patients. Medically necessary actions on patients that could result in aerosol formation should be performed with extreme care and preparation.