Prevention of invasive ventilation (PRiVENT)-a prospective, mixed-methods interventional, multicentre study with a parallel comparison group: study protocol.

BACKGROUND: Invasive mechanical ventilation (IMV) is a standard therapy for intensive care patients with respiratory failure. With increasing population age and multimorbidity, the number of patients who cannot be weaned from IMV increases, resulting in impaired quality of life and high costs. In addition, human resources are tied up in the care of these patients. METHODS: The PRiVENT intervention is a prospective, mixed-methods interventional, multicentre study with a parallel comparison group selected from insurance claims data of the health insurer Allgemeine Ortskrankenkasse Baden-Württemberg (AOK-BW) conducted in Baden-Württemberg, Germany, over 24 months. Four weaning centres supervise 40 intensive care units (ICUs), that are responsible for patient recruitment. The primary outcome, successful weaning from IMV, will be evaluated using a mixed logistic regression model. Secondary outcomes will be evaluated using mixed regression models. DISCUSSION: The overall objective of the PRiVENT project is the evaluation of strategies to prevent long-term IMV. Additional objectives aim to improve weaning expertise in and cooperation with the adjacent Intensive Care Units. TRIAL REGISTRATION: This study is registered at ClinicalTrials.gov (NCT05260853).

Predicting the successful application of high-flow nasal oxygen cannula in patients with COVID-19 respiratory failure: a retrospective analysis.

BACKGROUND: The right time of high-flow nasal cannulas (HFNCs) application in COVID-19 patients with acute respiratory failure remains uncertain. RESEARCH DESIGN AND METHODS: In this retrospective study, COVID-19-infected adult patients with hypoxemic respiratory failure were enrolled. Their baseline epidemiological data and respiratory failure related parameters, including the Ventilation in COVID-19 Estimation (VICE), and the ratio of oxygen saturation (ROX index), were recorded. The primary outcome measured was the 28-day mortality. RESULTS: A total of 69 patients were enrolled. Fifty-four (78%) patients who intubated and received invasive mechanical ventilatory (MV) support on day 1 were enrolled in the MV group. The remaining fifteen (22%) patients received HFNC initially (HFNC group), in which, ten (66%) patients were not intubated during hospitalization were belong to HFNC-success group and five (33%) of these patients were intubated later due to disease progression were attributed to HFNC-failure group. Compared with those in the MV group, those in the HFNC group had a lower mortality rate (6.7% vs. 40.7%, p = 0.0138). There were no differences in baseline characteristics among the two groups; however, the HFNC group had a lower VICE score (0.105 [0.049-0.269] vs. 0.260 [0.126-0.693], p = 0.0092) and higher ROX index (5.3 [5.1-10.7] vs. 4.3 [3.9-4.9], p = 0.0007) than the MV group. The ROX index was higher in the HFNC success group immediately before (p = 0.0136) and up to 12 hours of HFNC therapy than in the HFNC failure group. CONCLUSIONS: Early intubation may be considered in patients with a higher VICE score or a lower ROX index. The ROX score during HFNCs use can provide an early warning sign of treatment failure. Further investigations are warranted to confirm these results.

High flow nasal cannulas (HFNCs) were widely used in patients with COVID-19 infection related hypoxemic respiratory failure. However, there were concerns about its failure and related delayed intubation may be associated with a higher mortality rate. This retrospective study revealed patients with higher baseline disease severity and higher VICE scores may be treated with primary invasive mechanical ventilation. On the contrary, if their baseline VICE score is low and ROX index is high, HFNCs treatment might be safely applied initially. The trends of serial ROX index values during HFNC use could be a reliable periscope to predict the HFNC therapy outcome, therefore avoided delayed intubation.

Nasopharyngeal SARS-CoV-2 may not be dispersed by a high-flow nasal cannula.

A high-flow nasal cannula (HFNC) therapy plays a significant role in providing respiratory support to critically ill patients with coronavirus disease 2019 (COVID-19); however, the dispersion of the virus owing to aerosol generation is a matter of concern. This study aimed to evaluate if HFNC disperses the virus into the air. Among patients with COVID-19 admitted to private rooms with controlled negative pressure, we enrolled those admitted within 10 days of onset and requiring oxygenation through a conventional nasal cannula or HFNC therapy. Of the 17 patients enrolled, we obtained 22 samples (11 in the conventional nasal cannula group and 11 in the HFNC group). Viral RNA was detected in 20 nasopharyngeal swabs, and viable viruses were isolated from three nasopharyngeal swabs. Neither viral RNA nor viable virus was detected in the air sample at 0.5 m regardless of the oxygen-supplementation device. We detected viral RNA in two samples in the conventional nasal cannula group but not in the HFNC therapy group in gelatin filters located 3 m from the patient and the surface of the ventilation. This study directly demonstrated that despite viral RNA detection in the nasopharynx, viruses may not be dispersed by HFNC therapy. This warrants further research to determine if similar results can be obtained under different conditions.

Validation of Sequential ROX-Index Score Beyond 12 Hours in Predicting Treatment Failure and Mortality in COVID-19 Patients Receiving Oxygen via High-Flow Nasal Cannula.

Background: High-flow nasal cannula (HFNC) is an oxygen delivery method shown to reduce the risk of intubation and mortality in patients with type 1 respiratory failure. The ROX-index score can predict HFNC failure. This study aims to evaluate sequential ROX-index assessments as predictors of HFNC failure and mortality. Methods: Prospective observational single-center study including all adult patients with positive SARS-CoV-2 PCR placed under HFNC from 1st November 2020 to 31st May 2021, and patients with hemodynamic instability or unable to tolerate HFNC were excluded. The primary endpoint was successful HFNC de-escalation. Results: In univariate analysis, HFNC de-escalation was associated with younger age (59.2 ± 14 vs. 67.7 ± 10.5 and p < 0.001), lower levels of serum lactate (1.1 vs. 1.5 and p=0.013), and higher ROX-index at 12 hrs (5.09 vs. 4.13 and p < 0.001). ROC curve analysis of ROX-index at 12 hrs yielded a c-statistic of 71.2% (95% CI 61.6-80.9 and p < 0.001). ROX-index at 12 hrs and age retained significance in multivariate analysis. Using an optimal cutoff point of 4.43, we calculated a sensitivity of 64.5% and specificity of 69.6%. In univariate survival analysis, older age (68.8 ± 9.7 vs. 58.9 ± 13.9 and p < 0.001), greater creatinine values (0.96 vs. 0.84 and p=0.022), greater SOFA score (p=0.039), and a lower 12 hrs ROX-index (4.22 vs. 4.95 and p=0.02) were associated with hospital mortality. The SOFA score and age retained significance in multivariate survival analysis. Conclusion: ROX-index is proven to be a valuable and easy-to-use tool for clinicians in the assessment of COVID-19 patients under HFNC.

Techniques for Oxygenation and Ventilation in Coronavirus Disease 2019.

This paper discusses mechanisms of hypoxemia and interventions to oxygenate critically ill patients with COVID-19 which range from nasal cannula to noninvasive and mechanical ventilation. Noninvasive ventilation includes continuous positive airway pressure ventilation (CPAP) and high-flow nasal cannula (HFNC) with or without proning. The evidence for each of these modalities is discussed and thereafter, when to transition to mechanical ventilation (MV). Various techniques of MV, again with and without proning, and rescue strategies which would include extra corporeal membrane oxygenation (ECMO) when it is available and permissive hypoxemia where it is not, are discussed.

Characterization of SARS-CoV-2 Aerosols Dispersed During Noninvasive Respiratory Support of Patients With COVID-19.

BACKGROUND: In the midst of the COVID-19 pandemic, noninvasive respiratory support (NRS) therapies such as high-flow nasal cannula (HFNC) and noninvasive ventilation (NIV) were central to respiratory care. The extent to which these treatments increase the generation and dispersion of infectious respiratory aerosols is not fully understood. The objective of this study was to characterize SARS-CoV-2 aerosol dispersion from subjects with COVID-19 undergoing NRS therapy. METHODS: Several different aerosol sampling devices were used to collect air samples in the vicinity of 31 subjects with COVID-19, most of whom were receiving NRS therapy, primarily HFNC. Aerosols were collected onto filters and analyzed for the presence of SARS-CoV-2 RNA. Additional measurements were collected in an aerosol chamber with healthy adult subjects using respiratory therapy devices under controlled and reproducible conditions. RESULTS: Fifty aerosol samples were collected from subjects receiving HFNC or NIV therapy, whereas 6 samples were collected from subjects not receiving NRS. Only 4 of the 56 aerosol samples were positive for SARS-CoV-2 RNA, and all positive samples were collected using a high air flow scavenger mask collection device placed in close proximity to the subject. The chamber measurements with healthy subjects did not show any significant increase in aerosol dispersion caused by the respiratory therapy devices compared to baseline. CONCLUSIONS: Our findings demonstrate very limited detection of SARS-CoV-2-containing aerosols in the vicinity of subjects with COVID-19 receiving NRS therapies in the clinical setting. These results, combined with controlled chamber measurements showing that HFNC and NIV device usage was not associated with increased aerosol dispersion, suggest that NRS therapies do not result in increased dispersal of aerosols in the clinical setting.

[Clinical update in non-invasive positive pressure ventilation for respiratory failure in 2022].

In this article, we searched the research literatures related to clinical investigation of non-invasive positive pressure ventilation (NPPV) in acute respiratory failure(ARF)/chronic respiratory failure(CRF) between 1st October 2021 and 30th September 2022 through Medline, and reviewed the important advances. Three prospective randomized controlled studies related to the efficacy and safety of NPPV and/or high-flow nasal cannula oxygen therapy (HFNC) on patients with COVID-19 with ARF were reported, showing that NPPV (including continuous positive airway pressure and bilevel positive airway pressure) was able to reduce the intubation rate, but the efficacy of HFNC was contradictory. In addition, progress has been made in outcome prediction models for ARF treated with NPPV, NPPV-related cardiac arrest, and the impact of human-machine interface on NPPV treatment outcomes. The effects of NPPV as preoxygenation method before intubation was reported to be able to reduce severe desaturation during intubation, especially in obese population. The use of NPPV in extubated patients resulting in reduced reintubation rate was also studied. With regard to long-term home application of NPPV, five indicators of successful initiation were proposed, but the success rate was low in clinical practice. Some reports showed that psychological support could improve the adherence to NPPV. The results of these studies contributed to the rational selection and optimal application of NPPV in clinical practice.

Hypopharynx, oropharynx morphology and histology in severe Coronavirus 2 patients treated by noninvasive ventilation: comparison between full-face mask and helmet strategies.

BACKGROUND: Non-invasive ventilation may alter the morphology and histology of the upper airway mucosa. This study aimed to investigate the alterations of hypopharynx and oropharynx mucosa, identified during oro-tracheal intubation procedure via video-assisted laryngoscopy, in severe acute respiratory syndrome Coronavirus 2 related, treated by non-invasive ventilation via full-face mask or helmet. METHODS: Data of patients affected by Coronavirus 2 admitted to COVID Hospital of L'Aquila (Italy), presenting hypopharynx and oropharynx morphology alterations, requiring oro-tracheal intubation for invasive ventilation and initially treated with non-invasive ventilation were included in the study. The study aimed to investigate the upper airway mucosa alterations using oropharyngeal and hypopharyngeal images and biopsies taken during video-assisted-laryngoscopy. Data from the hypopharynx and oropharynx morphology and histology alterations between non-invasive ventilation via a full-face mask or helmet used during hospitalization were compared. RESULTS: From 220 data recorded, 60 patients were included in the study and classified into non-invasive ventilation full-face mask group (30/60) and via helmet group. Comparing data between groups, significant differences were found with respect to hyperemia (77% vs. 20%), laryngeal bleeding ulcerations (87% vs. 13%), and vocal cord edema with >50% narrowing of the tracheal lumen (73% vs. 7%), respectively. The histology examination revealed fibrin-necrotic exudate with extensive necrotic degenerative changes in the sample tissue of the groups. There were not any differences in the duration time of non-invasive ventilation, time from hospitalization and the start of ventilation between groups. CONCLUSIONS: The data from this research suggested that there were differences in airway mucosa damages among patients treated with a full-face mask or helmet. Further studies should be planned to understand which non-invasive ventilation support may mitigate upper airway mucosa damages when oro-tracheal intubation is requested for invasive respiratory support.

Effectiveness of an adapted diving mask (Owner mask) for non-invasive ventilation in the COVID-19 pandemic scenario: study protocol for a randomized clinical trial.

BACKGROUND: Non-invasive ventilation (NIV) is indicated to avoid orotracheal intubation (OTI) to reduce hospital stay and mortality. Patients infected by SARS-CoV2 can progress to respiratory failure (RF); however, in the initial phase, they can be submitted to oxygen therapy and NIV. Such resources can produce aerosol and can cause a high risk of contagion to health professionals. Safe NIV strategies are sought, and therefore, the authors adapted diving masks to be used as NIV masks (called an Owner mask). OBJECTIVE: To assess the Owner mask safety and effectiveness regarding conventional orofacial mask for patients in respiratory failure with and without confirmation or suspicion of COVID-19. METHODS: A Brazilian multicentric study to assess patients admitted to the intensive care unit regarding their clinical, sociodemographic and anthropometric data. The primary outcome will be the rate of tracheal intubation, and secondary outcomes will include in-hospital mortality, the difference in PaO2/FiO2 ratio and PaCO2 levels, time in the intensive care unit and hospitalization time, adverse effects, degree of comfort and level of satisfaction of the mask use, success rate of NIV (not progressing to OTI), and behavior of the ventilatory variables obtained in NIV with an Owner mask and with a conventional face mask. Patients with COVID-19 and clinical signs indicative of RF will be submitted to NIV with an Owner mask [NIV Owner COVID Group (n = 63)] or with a conventional orofacial mask [NIV orofacial COVID Group (n = 63)], and those patients in RF due to causes not related to COVID-19 will be allocated into the NIV Owner Non-COVID Group (n = 97) or to the NIV Orofacial Non-COVID Group (n = 97) in a randomized way, which will total 383 patients, admitting 20% for loss to follow-up. DISCUSSION: This is the first randomized and controlled trial during the COVID-19 pandemic about the safety and effectiveness of the Owner mask compared to the conventional orofacial mask. Experimental studies have shown that the Owner mask enables adequate sealing on the patient's face and the present study is relevant as it aims to minimize the aerosolization of the virus in the environment and improve the safety of health professionals. TRIAL REGISTRATION: Brazilian Registry of Clinical Trials (ReBEC): RBR - 7xmbgsz . Registered on 15 April 2021.

Outcomes of COVID-19 Patients Admitted to the Intermediate Respiratory Care Unit: Non-Invasive Respiratory Therapy in a Sequential Protocol.

The intermediate respiratory care units (IRCUs) have a pivotal role managing escalation and de-escalation between the general wards and the intensive care units (ICUs). Since the COVID-19 pandemic began, the early detection of patients that could improve on non-invasive respiratory therapies (NRTs) in IRCUs without invasive approaches is crucial to ensure proper medical management and optimize limiting ICU resources. The aim of this study was to assess factors associated with survival, ICU admission and intubation likelihood in COVID-19 patients admitted to IRCUs. Observational retrospective study in consecutive patients admitted to the IRCU of a tertiary hospital from March 2020 to April 2021. Inclusion criteria: hypoxemic respiratory failure (SpO2 ≤ 94% and/or respiratory rate ≥ 25 rpm with FiO2 > 50% supplementary oxygen) due to acute COVID-19 infection. Demographic, comorbidities, clinical and analytical data, and medical and NRT data were collected at IRCU admission. Multivariate logistic regression models assessed factors associated with survival, ICU admission, and intubation. From 679 patients, 79 patients (12%) had an order to not do intubation. From the remaining 600 (88%), 81% survived, 41% needed ICU admission and 37% required intubation. In the IRCU, 51% required non-invasive ventilation (NIV group) and 49% did not (non-NIV group). Older age and lack of corticosteroid treatment were associated with higher mortality and intubation risk in the scheme, which could be more beneficial in severe forms. Initial NIV does not always mean worse outcomes.

Early prediction of noninvasive ventilation failure after extubation: development and validation of a machine-learning model.

BACKGROUND: Noninvasive ventilation (NIV) has been widely used in critically ill patients after extubation. However, NIV failure is associated with poor outcomes. This study aimed to determine early predictors of NIV failure and to construct an accurate machine-learning model to identify patients at risks of NIV failure after extubation in intensive care units (ICUs). METHODS: Patients who underwent NIV after extubation in the eICU Collaborative Research Database (eICU-CRD) were included. NIV failure was defined as need for invasive ventilatory support (reintubation or tracheotomy) or death after NIV initiation. A total of 93 clinical and laboratory variables were assessed, and the recursive feature elimination algorithm was used to select key features. Hyperparameter optimization was conducted with an automated machine-learning toolkit called Neural Network Intelligence. A machine-learning model called Categorical Boosting (CatBoost) was developed and compared with nine other models. The model was then prospectively validated among patients enrolled in the Cardiac Surgical ICU of Zhongshan Hospital, Fudan University. RESULTS: Of 929 patients included in the eICU-CRD cohort, 248 (26.7%) had NIV failure. The time from extubation to NIV, age, Glasgow Coma Scale (GCS) score, heart rate, respiratory rate, mean blood pressure (MBP), saturation of pulse oxygen (SpO2), temperature, glucose, pH, pressure of oxygen in blood (PaO2), urine output, input volume, ventilation duration, and mean airway pressure were selected. After hyperparameter optimization, our model showed the greatest accuracy in predicting NIV failure (AUROC: 0.872 [95% CI 0.82-0.92]) among all predictive methods in an internal validation. In the prospective validation cohort, our model was also superior (AUROC: 0.846 [95% CI 0.80-0.89]). The sensitivity and specificity in the prediction group is 89% and 75%, while in the validation group they are 90% and 70%. MV duration and respiratory rate were the most important features. Additionally, we developed a web-based tool to help clinicians use our model. CONCLUSIONS: This study developed and prospectively validated the CatBoost model, which can be used to identify patients who are at risk of NIV failure. Thus, those patients might benefit from early triage and more intensive monitoring. TRIAL REGISTRATION: NCT03704324. Registered 1 September 2018, https://register. CLINICALTRIALS: gov .

Comparison between high-flow nasal cannula and noninvasive ventilation in COVID-19 patients: a systematic review and meta-analysis.

BACKGROUND: High-flow nasal cannula (HFNC) and noninvasive ventilation (NIV) are important treatment approaches for acute hypoxemic respiratory failure (AHRF) in coronavirus disease 2019 (COVID-19) patients. However, the differential impact of HFNC versus NIV on clinical outcomes of COVID-19 is uncertain. OBJECTIVES: We assessed the effects of HFNC versus NIV (interface or mode) on clinical outcomes of COVID-19. METHODS: We searched PubMed, EMBASE, Web of Science, Scopus, MedRxiv, and BioRxiv for randomized controlled trials (RCTs) and observational studies (with a control group) of HFNC and NIV in patients with COVID-19-related AHRF published in English before February 2022. The primary outcome of interest was the mortality rate, and the secondary outcomes were intubation rate, PaO2/FiO2, intensive care unit (ICU) length of stay (LOS), hospital LOS, and days free from invasive mechanical ventilation [ventilator-free day (VFD)]. RESULTS: In all, 23 studies fulfilled the selection criteria, and 5354 patients were included. The mortality rate was higher in the NIV group than the HFNC group [odds ratio (OR) = 0.66, 95% confidence interval (CI): 0.51-0.84, p = 0.0008, I2 = 60%]; however, in this subgroup, no significant difference in mortality was observed in the NIV-helmet group (OR = 1.21, 95% CI: 0.63-2.32, p = 0.57, I2 = 0%) or NIV-continuous positive airway pressure (CPAP) group (OR = 0.77, 95% CI: 0.51-1.17, p = 0.23, I2 = 65%) relative to the HFNC group. There were no differences in intubation rate, PaO2/FiO2, ICU LOS, hospital LOS, or days free from invasive mechanical ventilation (VFD) between the HFNC and NIV groups. CONCLUSION: Although mortality was lower with HFNC than NIV, there was no difference in mortality between HFNC and NIV on a subgroup of helmet or CPAP group. Future large sample RCTs are necessary to prove our findings. REGISTRATION: This systematic review and meta-analysis protocol was prospectively registered with PROSPERO (no. CRD42022321997).

High-Flow Nasal Cannula Versus Noninvasive Ventilation in Patients With COVID-19.

BACKGROUND: High-flow nasal cannula (HFNC) oxygen and noninvasive ventilation (NIV) have been widely used in patients with acute hypoxic respiratory failure (AHRF) due to COVID-19. However, the impact of HFNC versus NIV on clinical outcomes of COVID-19 is uncertain. Therefore, we performed this meta-analysis to evaluate the effect of HFNC versus NIV in COVID-19-related AHRF. METHODS: Several electronic databases were searched through February 10, 2022, for eligible studies comparing HFNC and NIV in COVID-19-related AHRF. Our primary outcome was intubation. The secondary outcomes were mortality, hospital length of stay (LOS), and PaO2 /FIO2 changes. Pooled risk ratio (RR) and mean difference (MD) with the corresponding 95% CI were obtained using a random-effect model. Prediction intervals were calculated to indicate the variance in outcomes that would be expected if new studies were conducted in the future. RESULTS: Nineteen studies involving 3,606 subjects (1,880 received HFNC and 1,726 received NIV) were included. There were no differences in intubation (RR 1.01 [95% CI 0.85-1.20], P = .89) or LOS (MD 0.38 d [95% CI -0.61 to 1.37], P = .45) between groups, with consistent results on the subgroup of randomized controlled trials (RCTs). Mortality was lower in NIV (RR 0.81 [95% CI 0.66-0.98], P = .03). However, the prediction interval was 0.41-1.59, and subgroup analysis of RCTs showed no difference in mortality between groups. There was a greater improvement in PaO2 /FIO2 with NIV (MD 22.80 [95% CI 5.30-40.31], P = .01). CONCLUSIONS: Our study showed that despite the greater improvement in PaO2 /FIO2 with NIV, intubation rates and LOS were similar between HFNC and NIV. Although mortality was lower with HFNC than NIV, the prediction interval included the null value, and there was no difference in mortality between HFNC and NIV on a subgroup of RCTs. Future large-scale RCTs are necessary to support our findings.

Higher mortality and intubation rate in COVID-19 patients treated with noninvasive ventilation compared with high-flow oxygen or CPAP.

The effectiveness of noninvasive respiratory support in severe COVID-19 patients is still controversial. We aimed to compare the outcome of patients with COVID-19 pneumonia and hypoxemic respiratory failure treated with high-flow oxygen administered via nasal cannula (HFNC), continuous positive airway pressure (CPAP) or noninvasive ventilation (NIV), initiated outside the intensive care unit (ICU) in 10 university hospitals in Catalonia, Spain. We recruited 367 consecutive patients aged ≥ 18 years who were treated with HFNC (155, 42.2%), CPAP (133, 36.2%) or NIV (79, 21.5%). The main outcome was intubation or death at 28 days after respiratory support initiation. After adjusting for relevant covariates and taking patients treated with HFNC as reference, treatment with NIV showed a higher risk of intubation or death (hazard ratio 2.01; 95% confidence interval 1.32-3.08), while treatment with CPAP did not show differences (0.97; 0.63-1.50). In the context of the pandemic and outside the intensive care unit setting, noninvasive ventilation for the treatment of moderate to severe hypoxemic acute respiratory failure secondary to COVID-19 resulted in higher mortality or intubation rate at 28 days than high-flow oxygen or CPAP. This finding may help physicians to choose the best noninvasive respiratory support treatment in these patients.Clinicaltrials.gov identifier: NCT04668196.

Semiquantitative Chest CT Severity Score Predicts Failure of Noninvasive Positive-Pressure Ventilation in Patients Hospitalized for COVID-19 Pneumonia.

OBJECTIVE: Noninvasive positive-pressure ventilation (NPPV) emerged as an efficient tool for treatment of COVID-19 pneumonia. The factors influencing NPPV failure still are elusive. The aim of the study was to investigate the relationships between semiquantitative chest computed tomography (CT) scoring and NPPV failure and mortality in patients with COVID-19. DESIGN: Observational study. SETTING: Nonintensive care setting. PARTICIPANTS: A total of 112 patients consecutively admitted for COVID-19 pneumonia. INTERVENTIONS: Usual care including various degrees of respiratory support. MEASUREMENTS AND MAIN RESULTS: The semiquantitative CT score was calculated at hospital admission. Subgroups were identified according to the ventilation strategy used (oxygen delivered by Venturi mask n = 53; NPPV-responder n = 38; NPPV-failure n = 21). The study's primary endpoint was the use of NPPV. The secondary endpoints were NPPV failure and in-hospital death, respectively. CT score progressively increased among groups (six v nine v 14, p < 0.05 among all). CT score was an independent predictor of all study endpoints (primary endpoint: 1.25 [95% confidence interval {CI} 1.1-1.4], p = 0.001; NPPV failure: 1.41 [95% CI 1.18-1.69], p < 0.001; in-hospital mortality: 1.21 [95% CI 1.07-1.38], p = 0.003). According to receiver operator characteristics curve analysis, CT score was the most accurate variable for prediction of NPPV failure (area under the curve 0.862 with p < 0.001; p < 0.05 v other variables). CONCLUSIONS: The authors reported the common and effective use of NPPV in patients with COVID-19 pneumonia. In the authors' population, a semiquantitative chest CT analysis at hospital admission accurately identified those patients responding poorly to NPPV.

Effects of non-invasive respiratory supports on inspiratory effort in moderate-severe COVID-19 patients. A randomized physiological study.

RATIONALE AND OBJECTIVE: Various forms of Non-invasive respiratory support (NRS) have been used during COVID-19, to treat Hypoxemic Acute Respiratory Failure (HARF), but it has been suggested that the occurrence of strenuous inspiratory efforts may cause Self Induced Lung Injury(P-SILI). The aim of this investigation was to record esophageal pressure, when starting NRS application, so as to better understand the potential risk of the patients in terms of P-SILI and ventilator induced lung injury (VILI). METHODS AND MEASUREMENTS: 21 patients with early de-novo respiratory failure due to COVID-19, underwent three 30 min trials applied in random order: high-flow nasal cannula (HFNC), continuous positive airway pressure (CPAP), and non-invasive ventilation (NIV). After each trial, standard oxygen therapy was reinstituted using a Venturi mask (VM). 15 patients accepted a nasogastric tube placement. Esophageal Pressure (ΔPes) and dynamic transpulmonary driving pressure (ΔPLDyn), together with the breathing pattern using a bioelectrical impedance monitor were recorded. Arterial blood gases were collected in all patients. MAIN RESULTS: No statistically significant differences in breathing pattern and PaCO2 were found. PaO2/FiO2 ratio improved significantly during NIV and CPAP vs VM. NIV was the only NRS to reduce significantly ΔPes vs. VM (-10,2 ±5 cmH20 vs -3,9 ±3,4). No differences were found in ΔPLDyn between NRS (10,2±5; 9,9±3,8; 7,6±4,3; 8,8±3,6 during VM, HFNC, CPAP and NIV respectively). Minute ventilation (Ve) was directly dependent on the patient's inspiratory effort, irrespective of the NRS applied. 14% of patients were intubated, none of them showing a reduction in ΔPes during NRS. CONCLUSIONS: In the early phase of HARF due to COVID-19, the inspiratory effort may not be markedly elevated and the application of NIV and CPAP ameliorates oxygenation vs VM. NIV was superior in reducing ΔPes, maintaining ΔPLDyn within a range of potential safety.