Comprehensive bronchoalveolar lavage characterization in COVID-19 associated acute respiratory distress syndrome patients: a prospective cohort study.

COVID-19-related acute respiratory distress syndrome (CARDS) is associated with high mortality rates. We still have limited knowledge of the complex alterations developing in the lung microenvironment. The goal of the present study was to comprehensively analyze the cellular components, inflammatory signature, and respiratory pathogens in bronchoalveolar lavage (BAL) of CARDS patients (16) in comparison to those of other invasively mechanically ventilated patients (24). In CARDS patients, BAL analysis revealed: SARS-CoV-2 infection frequently associated with other respiratory pathogens, significantly higher neutrophil granulocyte percentage, remarkably low interferon-gamma expression, and high levels of interleukins (IL)-1ß and IL-9. The most important predictive variables for worse outcomes were age, IL-18 expression, and BAL neutrophilia. To the best of our knowledge, this is the first study that was able to identify, through a comprehensive analysis of BAL, several aspects relevant to the complex pathophysiology of CARDS.

Development and Validation of an Acute Respiratory Distress Syndrome Prediction Model in Coronavirus Disease 2019: Updated Lung Injury Prediction Score.

OBJECTIVE: To develop and validate an updated lung injury prediction score for coronavirus disease 2019 (COVID-19) (c-LIPS) tailored for predicting acute respiratory distress syndrome (ARDS) in COVID-19. PATIENTS AND METHODS: This was a registry-based cohort study using the Viral Infection and Respiratory Illness Universal Study. Hospitalized adult patients between January 2020 and January 2022 were screened. Patients who qualified for ARDS within the first day of admission were excluded. Development cohort consisted of patients enrolled from participating Mayo Clinic sites. The validation analyses were performed on remaining patients enrolled from more than 120 hospitals in 15 countries. The original lung injury prediction score (LIPS) was calculated and enhanced using reported COVID-19-specific laboratory risk factors, constituting c-LIPS. The main outcome was ARDS development and secondary outcomes included hospital mortality, invasive mechanical ventilation, and progression in WHO ordinal scale. RESULTS: The derivation cohort consisted of 3710 patients, of whom 1041 (28.1%) developed ARDS. The c-LIPS discriminated COVID-19 patients who developed ARDS with an area under the curve (AUC) of 0.79 compared with original LIPS (AUC, 0.74; P<.001) with good calibration accuracy (Hosmer-Lemeshow P=.50). Despite different characteristics of the two cohorts, the c-LIPS's performance was comparable in the validation cohort of 5426 patients (15.9% ARDS), with an AUC of 0.74; and its discriminatory performance was significantly higher than the LIPS (AUC, 0.68; P<.001). The c-LIPS's performance in predicting the requirement for invasive mechanical ventilation in derivation and validation cohorts had an AUC of 0.74 and 0.72, respectively. CONCLUSION: In this large patient sample c-LIPS was successfully tailored to predict ARDS in COVID-19 patients.

Inhaled prostacyclin therapy in the acute respiratory distress syndrome: a randomized controlled multicenter trial.

BACKGROUND: Acute respiratory distress syndrome (ARDS) results in significant hypoxia, and ARDS is the central pathology of COVID-19. Inhaled prostacyclin has been proposed as a therapy for ARDS, but data regarding its role in this syndrome are unavailable. Therefore, we investigated whether inhaled prostacyclin would affect the oxygenation and survival of patients suffering from ARDS. METHODS: We performed a prospective randomized controlled single-blind multicenter trial across Germany. The trial was conducted from March 2019 with final follow-up on 12th of August 2021. Patients with moderate to severe ARDS were included and randomized to receive either inhaled prostacyclin (3 times/day for 5 days) or sodium chloride (Placebo). The primary outcome was the oxygenation index in the intervention and control groups on Day 5 of therapy. Secondary outcomes were mortality, secondary organ failure, disease severity and adverse events. RESULTS: Of 707 patients approached 150 patients were randomized to receive inhaled prostacyclin (n = 73) or sodium chloride (n = 77). Data from 144 patients were analyzed. The baseline PaO2/FiO2 ratio did not differ between groups. The primary analysis of the study was negative, and prostacyclin improved oxygenation by 20 mmHg more than Placebo (p = 0.17). Secondary analysis showed that the oxygenation was significantly improved in patients with ARDS who were COVID-19-positive (34 mmHg, p = 0.04). Mortality did not differ between groups. Secondary organ failure and adverse events were similar in the intervention and control groups. CONCLUSIONS: The primary result of our study was negative. Our data suggest that inhaled prostacyclin might be beneficial treatment in patients with COVID-19 induced ARDS. TRIAL REGISTRATION: The study was approved by the Institutional Review Board of the Research Ethics Committee of the University of Tübingen (899/2018AMG1) and the corresponding ethical review boards of all participating centers. The trial was also approved by the Federal Institute for Drugs and Medical Devices (BfArM, EudraCT No. 2016003168-37) and registered at clinicaltrials.gov (NCT03111212) on April 6th 2017.

Pregnancy and Severe ARDS with COVID-19: Epidemiology, Diagnosis, Outcomes and Treatment.

Pregnancy-related acute respiratory distress syndrome (ARDS) is fast becoming a growing and clinically relevant subgroup of ARDS amidst global outbreaks of various viral respiratory pathogens that include H1N1-influenza, severe acute respiratory syndrome (SARS), middle east respiratory syndrome (MERS), and the most recent COVID-19 pandemic. Pregnancy is a risk factor for severe viral-induced ARDS and commonly associated with poor maternal and fetal outcomes including fetal growth-restriction, preterm birth, and spontaneous abortion. Physiologic changes of pregnancy further compounded by mechanical and immunologic alterations are theorized to impact the development of ARDS from viral pneumonia. The COVID-19 sub-phenotype of ARDS share overlapping molecular features of maternal pathogenicity of pregnancy with respect to immune-dysregulation and endothelial/microvascular injury (i.e., preeclampsia) that may in part explain a trend toward poor maternal and fetal outcomes seen with severe COVID-19 maternal infections. To date, current ARDS diagnostic criteria and treatment management fail to include and consider physiologic adaptations that are unique to maternal physiology of pregnancy and consideration of maternal-fetal interactions. Treatment focused on lung-protective ventilation strategies have been shown to improve clinical outcomes in adults with ARDS but may have adverse maternal-fetal interactions when applied in pregnancy-related ARDS. No specific pharmacotherapy has been identified to improve outcomes in pregnancy with ARDS. Adjunctive therapies aimed at immune-modulation and anti-viral treatment with COVID-19 infection during pregnancy have been reported but data in regard to its efficacy and safety is currently lacking.

Comparison of Pediatric Patients With and Without Multisystem Inflammatory Syndrome Associated With COVID-19: Retrospective Cohort From Ecuador.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) has been associated with severe acute respiratory syndrome coronavirus 2 infection in the pediatric population cared for in the pediatric intensive care unit. We aimed to compare patients with pediatric acute respiratory distress syndrome (PARDS) with those who also present a MIS-C diagnosis (PARDS vs. PARDS + MIS-C). METHODS: One hundred and sixty-seven children (0-15 years) admitted to the pediatric intensive care unit COVID-19 ward of a national reference children's hospital in Quito, Ecuador, from June 2020 to June 2021 who developed PARDS with or without MIS-C. To diagnose PARDS, the criteria of the Pediatric Acute Lung Injury Consensus Conference Group were used, and to diagnose MIS-C, the criteria of the Centers for Disease Control and Prevention were used. Additionally, the PRISM score was used to calculate the mortality risk of study patients on admission. RESULTS: Of the 167 patients with PARDS, ~59% also developed MIS-C. Patients with PARDS + MIS-C had higher risks than patients without MIS-C in the following: frequency of associated bacterial infections (81.6% vs. 55.1%), mortality risk (36.7% vs. 11.6%), use of respiratory support (invasive mechanical ventilation: 92% vs. 86%), use of vasopressors/inotropes (90.8% vs. 30.4%), renal complications (36.7% vs. 8.7%), septic shock (84.7% vs. 20.3%), multiorgan failure (39.8% vs. 1.4%) and mortality at discharge (39.8% vs. 4.3%). Logistic regression failed to find an association between MIS-C and age, race, sex, ≥3 signs/symptoms and ≥2 comorbidities. CONCLUSIONS: Patients with PARDS + MIS-C had a more severe clinical picture than patients without MIS-C. The findings provide useful information to improve the management of PARDS patients with and without MIS-C in Ecuador.

[Dead space fraction for treatment guidance and prognosis evaluation of acute respiratory distress syndrome].

Acute respiratory distress syndrome (ARDS) is a common cause of critical illness and high mortality from respiratory failure. Increased dead space fraction (VD/VT) was independently associated with lung injury and mortality of ARDS. VD/VT is readily obtained by bedside measurements of arterial blood gas and end-tidal carbon dioxide. Early attention and application of VD/VT as an indicator will help to better understand the pathophysiological of ARDS, guide clinical treatment, and better assess the severity and clinical prognosis of the disease.

Lung ultrasound monitoring: impact on economics and outcomes.

PURPOSE OF REVIEW: This review aims to summarize the impact of lung ultrasonography (LUS) on economics and possible impact on patients' outcomes, proven its diagnostic accuracy in patients with acute respiratory failure. RECENT FINDINGS: Despite some previous ethical concerns on LUS examination, today this technique has showed several advantages. First, it is now clear that the daily use of LUS can provide a relevant cost reduction in healthcare of patients with acute respiratory failure, while reducing the risk of transport of patients to radiological departments for chest CT scan. In addition, LUS reduces the exposition to x-rays since can replace the bedside chest X-ray examination in many cases. Indeed, LUS is characterized by a diagnostic accuracy that is even superior to portable chest X-ray when performed by well trained personnel. Finally, LUS examination is a useful tool to predict the course of patients with pneumonia, including the need for hospitalization and ICU admission, noninvasive ventilation failure and orotracheal intubation, weaning success, and mortality. SUMMARY: LUS should be implemented not only in Intensive Care Units, but also in other setting like emergency departments. Since most data comes from the recent coronavirus disease 2019 pandemic, further investigations are required in Acute Respiratory Failure of different etiologies.

Case Report: Recurrence of Acute Respiratory Distress Syndrome After Bilateral Lung Transplantation.

BACKGROUND: The main causes of early respiratory failure after lung transplantation include primary graft dysfunction (PGD), acute rejection, and infection. This report describes a case of unclear early respiratory failure after bilateral lung transplantation for extensive COVID-19-induced acute respiratory distress syndrome (ARDS). METHODS: We reviewed the patient file to investigate the course of the functional decline and evaluate reasons for early graft failure. Analyzed data included crossmatching results, biopsy results, HLA antibodies testing, bronchoalveolar lavages, respiratory parameters, and medications. RESULTS: After an initial excellent early postoperative course, the patient developed progressive respiratory failure, making re-implantation of extracorporeal membrane oxygenation (ECMO) support necessary. An extensive diagnostic workup revealed no signs of infection or rejection. Because the patient showed no signs of improvement with any treatment, lung-protective ventilation with the intermittent prone position was initiated. The patient's respiratory situation and bilateral opacities slowly improved over the next few weeks, and ECMO support was eventually discontinued. CONCLUSION: With no evidence of PGD, rejection, or infection, recurrent ARDS caused by a systemic immunologic process was seen as the only plausible cause for the patient's respiratory failure after lung transplantation. The fact that ARDS can develop extrapulmonarily, without direct viral or bacterial damage, makes us conclude that the preceding systemic activation and recruitment of immune cells by the primarily injured lung could potentially lead to the recurrence of ARDS even if the injured organ is removed.

Critically ill infants with SARS-COV-2 delta variant infection.

BACKGROUND: SARS-CoV-2 is described to cause mild to moderate symptoms in children. To date, clinical data and symptoms of the Delta variant in pediatric patients are lacking. AIM: To describe clinical characteristics and outcomes of infants admitted in the pediatric intensive care unit (PICU) during the period of Delta variant predominance. METHODS: We performed a retrospective study, between June 23, 2021 and August 16, 2021. We included children aged under 15 years, admitted to PICU with severe and critical form of SARS-CoV-2 infection as confirmed by RT-PCR. We reviewed medical records for all patients. RESULTS: During the study period, 20 infants were included. The median age was 47 days (IQR: 26.5-77). The sex ratio was 0.8 (9 males). No underlying medical conditions were noted. Parents were not vaccinated. Respiratory involvement was the main feature to be observed in our cohort. Eleven patients had pediatric acute respiratory distress (PARDS) with a median oxygen saturation index (OSI) of 9 (IQR: 7-11). PARDS was mild in 4 cases, moderate in 5 cases and severe in 2 cases. Hemodynamic instability was observed in 4 cases. The main radiological finding was ground glass opacities in 11 cases. Seventeen patients were mechanically ventilated and 3 of them were escalated to high-frequency oscillatory ventilation. The median duration of mechanical ventilation was 6 days (IQR 2.5-12.5). The remaining patients were managed with high flow nasal cannula. Four patients died. CONCLUSION: We report herein a case series of very young infants, with no comorbidities, and with a life-threatening illness due to SARS-CoV-2 Delta variant.

ARDS: hidden perils of an overburdened diagnosis.

A diagnosis of ARDS serves as a pretext for several perilous clinical practices. Clinical trials demonstrated that tidal volume 12 ml/kg increases patient mortality, but 6 ml/kg has not proven superior to 11 ml/kg or anything in between. Present guidelines recommend 4 ml/kg, which foments severe air hunger, leading to prescription of hazardous (yet ineffective) sedatives, narcotics and paralytic agents. Inappropriate lowering of tidal volume also fosters double triggering, which promotes alveolar overdistention and lung injury. Successive panels have devoted considerable energy to developing a more precise definition of ARDS to homogenize the recruitment of patients into clinical trials. Each of three pillars of the prevailing Berlin definition is extremely flimsy and the source of confusion and unscientific practices. For doctors at the bedside, none of the revisions have enhanced patient care over that using the original 1967 description of Ashbaugh and colleagues. Bedside doctors are better advised to diagnose ARDS on the basis of pattern recognition and instead concentrate their vigilance on resolving the numerous hidden dangers that follow inevitably once a diagnosis has been made.

Non-invasive respiratory support in SARS-CoV-2 related acute respiratory distress syndrome: when is it most appropriate to start treatment?

BACKGROUND: Acute respiratory distress syndrome (ARDS) is one of the most severe complications of SARS-CoV-2 infection. Non-Invasive Respiratory Support (NRS) as Continuous Positive Airway Pressure (CPAP) and/or Non-Invasive Ventilation (NIV) has been proven as effective in the management of SARS-CoV-2-related ARDS. However, the most appropriate timing for start NRS is unknown. METHODS: We conducted a prospective pilot study including all consecutive patients who developed moderate SARS-CoV-2-related ARDS during hospitalization. Patients were randomly divided into two intervention groups according to ARDS severity (assessed by PaO2/FiO2-P/F) at NRS beginning: group A started CPAP/NIV when P/F was ≤ 200 and group B started CPAP/NIV when P/F was ≤ 150. Eligible patients who did not give their consent to CPAP/NIV until the severe stage of ARDS and started non-invasive treatment when P/F ≤ 100 (group C) was added. The considered outcomes were in-hospital mortality, oro-tracheal intubation (OTI) and days of hospitalization. RESULTS: Among 146 eligible patients, 29 underwent CPAP/NIV when P/F was ≤ 200 (Group A), 68 when P/F was ≤ 150 (Group B) and 31 patients agreed to non-invasive treatment only when P/F was ≤ 100 (Group C). Starting NRS at P/F level between 151 and 200 did not results in significant differences in the outcomes as compared to treatment starting with P/F ranging 101-150. Conversely, patients undergone CPAP/NIV in a moderate stage (P/F 101-200) had a significantly lower in-hospital mortality rate (13.4 vs. 29.0%, p = 0.044) and hospitalization length (14 vs. 15 days, p = 0.038) than those in the severe stage (P/F ≤ 100). Age and need for continuous ventilation were independent predictors of CPAP/NIV failure. CONCLUSIONS: Starting CPAP/NIV in patients with SARS-CoV-2-related ARDS in moderate stage (100 > P/F ≤ 200) is associated to a reduction of both in-hospital mortality and hospitalization length compared to the severe stage (P/F ≤ 100). Starting CPAP/NIV with a P/F > 150 does not appear to be of clinical utility.

Personalized medicine using omics approaches in acute respiratory distress syndrome to identify biological phenotypes.

In the last decade, research on acute respiratory distress syndrome (ARDS) has made considerable progress. However, ARDS remains a leading cause of mortality in the intensive care unit. ARDS presents distinct subphenotypes with different clinical and biological features. The pathophysiologic mechanisms of ARDS may contribute to the biological variability and partially explain why some pharmacologic therapies for ARDS have failed to improve patient outcomes. Therefore, identifying ARDS variability and heterogeneity might be a key strategy for finding effective treatments. Research involving studies on biomarkers and genomic, metabolomic, and proteomic technologies is increasing. These new approaches, which are dedicated to the identification and quantitative analysis of components from biological matrixes, may help differentiate between different types of damage and predict clinical outcome and risk. Omics technologies offer a new opportunity for the development of diagnostic tools and personalized therapy in ARDS. This narrative review assesses recent evidence regarding genomics, proteomics, and metabolomics in ARDS research.

Physiological response to prone positioning in intubated adults with COVID-19 acute respiratory distress syndrome: a retrospective study.

BACKGROUND: COVID-19 related acute respiratory distress syndrome (ARDS) has specific characteristics compared to ARDS in other populations. Proning is recommended by analogy with other forms of ARDS, but few data are available regarding its physiological effects in this population. This study aimed to assess the effects of proning on oxygenation parameters (PaO2/FiO2 and alveolo-arterial gradient (Aa-gradient)), blood gas analysis, ventilatory ratio (VR), respiratory system compliance (CRS) and estimated dead space fraction (VD/VT HB). We also looked for variables associated with treatment failure. METHODS: Retrospective monocentric study of intubated COVID-19 ARDS patients managed with an early intubation, low to moderate positive end-expiratory pressure and early proning strategy hospitalized from March 6 to April 30 2020. Blood gas analysis, PaO2/FiO2, Aa-gradient, VR, CRS and VD/VT HB were compared before and at the end of each proning session with paired t-tests or Wilcoxon tests (p < 0.05 considered as significant). Proportions were assessed using Fischer exact test or Chi square test. RESULTS: Forty-two patients were included for a total of 191 proning sessions, median duration of 16 (5-36) hours. Considering all sessions, PaO2/FiO2 increased (180 [148-210] vs 107 [90-129] mmHg, p < 0.001) and Aa-gradient decreased (127 [92-176] vs 275 [211-334] mmHg, p < 0.001) with proning. CRS (36.2 [30.0-41.8] vs 32.2 [27.5-40.9] ml/cmH2O, p = 0.003), VR (2.4 [2.0-2.9] vs 2.3 [1.9-2.8], p = 0.028) and VD/VT HB (0.72 [0.67-0.76] vs 0.71 [0.65-0.76], p = 0.022) slightly increased. Considering the first proning session, PaO2/FiO2 increased (186 [165-215] vs 104 [94-126] mmHg, p < 0.001) and Aa-gradient decreased (121 [89-160] vs 276 [238-321] mmHg, p < 0.001), while CRS, VR and VD/VT HB were unchanged. Similar variations were observed during the subsequent proning sessions. Among the patients who experienced treatment failure (defined as ICU death or need for extracorporeal membrane oxygenation), fewer expressed a positive response in terms of oxygenation (defined as increase of more than 20% in PaO2/FiO2) to the first proning (67 vs 97%, p = 0.020). CONCLUSION: Proning in COVID-19 ARDS intubated patients led to an increase in PaO2/FiO2 and a decrease in Aa-gradient if we consider all the sessions together, the first one or the 4 subsequent sessions independently. When considering all sessions, CRS increased and VR and VD/VT HB only slightly increased.

Angiocatheter Decompression on a Covid-19 Patient with severe Pneumonia, Pneumothorax, and Subcutaneous Emphysema.

BACKGROUND: A novel coronavirus, currently known as Severe Acute Respiratory Syndrome Coronavirus 2, causes Coronavirus disease 2019 (Covid-19). Its most significant complication is a kind of pneumonia known as of 2019 New Coronavirus-Infected Pneumonia (NCIP). Covid-19 pneumonia can have unusual complications that affect both lungs in a widespread manner. Acute lung damage and Acute Respiratory Distress Syndrome (ARDS) are typical in severe Covid-19 cases. Several potential risk factors cause the pneumonia associated with this disease, such as age over 65, diabetes, hypertension, chronic obstructive pulmonary disease, immunosuppression, and pregnancy. Furthermore, various laboratory markers like high levels of C-reactive protein (CRP), D-dimers, ferritin, interleukin-6 (IL-6), and LDH, as well as a low lymphocyte and thrombocyte count, have been linked to increased disease severity and a poor prognosis. METHODS: In this study, we present a case of a 45-year-old patient with a rare evolution of the disease, who made a full recovery against all odds. We highlight the atypical presentation of Covid-19 in this patient, who developed some unusual complications, such as pneumonia, pneumothorax, pneumomediastinum, and subcutaneous emphysema. RESULTS: There is a scarcity of information on patient-related variables linked to pneumothorax in severely sick Covid-19 patients. This study adds to the existing research, reinforcing that spontaneous pneumothorax can be caused by the infection itself, in addition to ventilator-induced trauma in mechanically ventilated patients. CONCLUSIONS: We conclude that patients with Covid-19 pneumonia may develop a more robust and systemic illness characterized by acute lung injury, acute respiratory distress syndrome (ARDS), shock, coagulopathy, and nu¬merous organ dysfunctions, all of which are linked with a high risk of death.

Safety and efficacy of corticosteroids in ARDS patients: a systematic review and meta-analysis of RCT data.

PURPOSE: Acute respiratory distress syndrome (ARDS) is an acute and critical disease among children and adults, and previous studies have shown that the administration of corticosteroids remains controversial. Therefore, a meta-analysis of randomized controlled trials (RCTs) was performed to evaluate the safety and efficacy of corticosteroids. METHODS: The RCTs investigating the safety and efficacy of corticosteroids in ARDS were searched from electronic databases (Embase, Medline, and the Cochrane Central Register of Controlled Trials). The primary outcome was 28-day mortality. Heterogeneity was assessed using the Chi square test and I2 with the inspection level of 0.1 and 50%, respectively. RESULTS: Fourteen RCTs (n = 1607) were included for analysis. Corticosteroids were found to reduce the risk of death in patients with ARDS (relative risk (RR) = 0.78, 95% confidence interval (CI): 0.70-0.87; P < 0.01). Moreover, no significant adverse events were observed, compared to placebo or standard support therapy. Further subgroup analysis showed that variables, such as adults (RR = 0.78; 95% CI: 0.70-0.88; P < 0.01), non-COVID-19 (RR = 0.71; 95% CI: 0.62-0.83; P < 0.01), methylprednisolone (RR = 0.70; 95% CI: 0.56-0.88; P < 0.01), and hydrocortisone (RR = 0.79; 95% CI: 0.63-0.98; P = 0.03) were associated with 28-day mortality among patients who used corticosteroids. However, no association was found, regarding children (RR = 0.21; 95% CI: 0.01-4.10; P = 0.30). CONCLUSION: The use of corticosteroids is an effective approach to reduce the risk of death in ARDS patients. However, this effect is associated with age, non-COVID-19 diseases, and methylprednisolone and hydrocortisone use. Therefore, evidence suggests patients with age ≥ 18 years and non-COVID-19 should be encouraged during the corticosteroid treatment. However, due to substantial differences in the use of corticosteroids among these studies, questions still remain regarding the dosage, optimal corticosteroid agent, and treatment duration in patients with ARDS.

Longitudinal respiratory subphenotypes in patients with COVID-19-related acute respiratory distress syndrome: results from three observational cohorts.

BACKGROUND: Patients with COVID-19-related acute respiratory distress syndrome (ARDS) have been postulated to present with distinct respiratory subphenotypes. However, most phenotyping schema have been limited by sample size, disregard for temporal dynamics, and insufficient validation. We aimed to identify respiratory subphenotypes of COVID-19-related ARDS using unbiased data-driven approaches. METHODS: PRoVENT-COVID was an investigator-initiated, national, multicentre, prospective, observational cohort study at 22 intensive care units (ICUs) in the Netherlands. Consecutive patients who had received invasive mechanical ventilation for COVID-19 (aged 18 years or older) served as the derivation cohort, and similar patients from two ICUs in the USA served as the replication cohorts. COVID-19 was confirmed by positive RT-PCR. We used latent class analysis to identify subphenotypes using clinically available respiratory data cross-sectionally at baseline, and longitudinally using 8-hourly data from the first 4 days of invasive ventilation. We used group-based trajectory modelling to evaluate trajectories of individual variables and to facilitate potential clinical translation. The PRoVENT-COVID study is registered with ClinicalTrials.gov, NCT04346342. FINDINGS: Between March 1, 2020, and May 15, 2020, 1007 patients were admitted to participating ICUs in the Netherlands, and included in the derivation cohort. Data for 288 patients were included in replication cohort 1 and 326 in replication cohort 2. Cross-sectional latent class analysis did not identify any underlying subphenotypes. Longitudinal latent class analysis identified two distinct subphenotypes. Subphenotype 2 was characterised by higher mechanical power, minute ventilation, and ventilatory ratio over the first 4 days of invasive mechanical ventilation than subphenotype 1, but PaO2/FiO2, pH, and compliance of the respiratory system did not differ between the two subphenotypes. 185 (28%) of 671 patients with subphenotype 1 and 109 (32%) of 336 patients with subphenotype 2 had died at day 28 (p=0·10). However, patients with subphenotype 2 had fewer ventilator-free days at day 28 (median 0, IQR 0-15 vs 5, 0-17; p=0·016) and more frequent venous thrombotic events (109 [32%] of 336 patients vs 176 [26%] of 671 patients; p=0·048) compared with subphenotype 1. Group-based trajectory modelling revealed trajectories of ventilatory ratio and mechanical power with similar dynamics to those observed in latent class analysis-derived trajectory subphenotypes. The two trajectories were: a stable value for ventilatory ratio or mechanical power over the first 4 days of invasive mechanical ventilation (trajectory A) or an upward trajectory (trajectory B). However, upward trajectories were better independent prognosticators for 28-day mortality (OR 1·64, 95% CI 1·17-2·29 for ventilatory ratio; 1·82, 1·24-2·66 for mechanical power). The association between upward ventilatory ratio trajectories (trajectory B) and 28-day mortality was confirmed in the replication cohorts (OR 4·65, 95% CI 1·87-11·6 for ventilatory ratio in replication cohort 1; 1·89, 1·05-3·37 for ventilatory ratio in replication cohort 2). INTERPRETATION: At baseline, COVID-19-related ARDS has no consistent respiratory subphenotype. Patients diverged from a fairly homogenous to a more heterogeneous population, with trajectories of ventilatory ratio and mechanical power being the most discriminatory. Modelling these parameters alone provided prognostic value for duration of mechanical ventilation and mortality. FUNDING: Amsterdam UMC.

Acute respiratory distress syndrome in adults: diagnosis, outcomes, long-term sequelae, and management.

Acute respiratory distress syndrome (ARDS) is characterised by acute hypoxaemic respiratory failure with bilateral infiltrates on chest imaging, which is not fully explained by cardiac failure or fluid overload. ARDS is defined by the Berlin criteria. In this Series paper the diagnosis, management, outcomes, and long-term sequelae of ARDS are reviewed. Potential limitations of the ARDS definition and evidence that could inform future revisions are considered. Guideline recommendations, evidence, and uncertainties in relation to ARDS management are discussed. The future of ARDS strives towards a precision medicine approach, and the framework of treatable traits in ARDS diagnosis and management is explored.

BIOMARKERS IN THE ACUTE RESPIRATORY DISTRESS SYNDROME: PAST, PRESENT, AND FUTURE.

Acute respiratory distress syndrome (ARDS), originally described in 1967, affects more than 3 million individuals each year throughout the world and accounts for approximately 10% of all admissions to the intensive care unit. Despite substantial progress in defining the epidemiology and pathogenesis of the syndrome, there is no specific treatment and mortality rates remain high. Barriers to finding specific therapeutic interventions include the inability to predict who will get ARDS, inadequate definitions and specific diagnostic markers, the heterogeneity of the patient population, complexities of the pathogenesis, and the impact of clinical care. Measurements of biomarkers have identified these barriers as well as contributed to the current understanding of the disease. The COVID-19 pandemic resulted in a dramatic increase in patients with ARDS, driving an urgent need to understand the pathogenesis and develop and implement therapeutic interventions. Past studies of biomarkers in ARDS can provide insight that could help to meet those needs more rapidly.

Lactate dehydrogenase/albumin ratio as a prognostic factor in severe acute respiratory distress syndrome cases associated with COVID-19.

BACKGROUND: Patients with severe acute respiratory distress syndrome (ARDS) have high mortality rates; therefore, new biomarkers are necessary to predict the prognosis in the early stages. Serum lactate dehydrogenase (LDH) level is a specific marker of lung damage, but it is not sensitive because it is affected by several factors. This study aimed to determine whether the LDH/albumin ratio could be used as a prognostic biomarker in patients with severe ARDS due to COVID 19. METHODS: Tertiary intensive care unit (ICU) patients with severe ARDS and confirmed COVID-19 diagnosis between August 1, 2020, and October 31, 2021, were included. The demographic and clinical characteristics of the patients were recorded from the hospital databases, together with laboratory results on the day of admission to the ICU and the length of stay in the ICU and hospital. LDH/albumin, lactate/albumin, C-reactive protein (CRP)/albumin, and BUN/albumin ratios were calculated. Logistic regression analysis was performed to determine independent risk factors affecting mortality. RESULTS: Nine hundred and five patients hospitalized in a tertiary ICU were evaluated. Three hundred fifty-one patients with severe ARDS were included in this study. The mortality rate of the included patients was 61.8% (of 217/351). LDH/albumin, lactate/albumin, and BUN/albumin ratios were higher in the nonsurvivor group (P < .001). The area under the curve (AUC) from the receiver operating characteristic analysis that predicted in-hospital mortality was 0.627 (95% confidence intervals (CI): 0.574-0.678, P < .001) for the LDH/albumin ratio, 0.605 (95% CI: 0.551-0.656, P < .001) for lactate/albumin, and 0.638 (95% CI: 0.585-0.688, P < .001) for BUN/albumin. However, LDH/albumin ratio was independently associated with mortality in multivariate logistic regression analysis. CONCLUSION: LDH/albumin ratio can be used as an independent prognostic factor for mortality in patients with severe ARDS caused by COVID-19.

Inhaled aviptadil for the possible treatment of COVID-19 in patients at high risk for ARDS: study protocol for a randomized, placebo-controlled, and multicenter trial.

BACKGROUND: Despite the fast establishment of new therapeutic agents in the management of COVID-19 and large-scale vaccination campaigns since the beginning of the SARS-CoV-2 pandemic in early 2020, severe disease courses still represent a threat, especially to patients with risk factors. This indicates the need for alternative strategies to prevent respiratory complications like acute respiratory distress syndrome (ARDS) associated with COVID-19. Aviptadil, a synthetic form of human vasoactive intestinal peptide, might be beneficial for COVID-19 patients at high risk of developing ARDS because of its ability to influence the regulation of exaggerated pro-inflammatory proteins and orchestrate the lung homeostasis. Aviptadil has recently been shown to considerably improve the prognosis of ARDS in COVID-19 when applied intravenously. An inhaled application of aviptadil has the advantages of achieving a higher concentration in the lung tissue, fast onset of activity, avoiding the hepatic first-pass metabolism, and the reduction of adverse effects. The overall objective of this project is to assess the efficacy and safety of inhaled aviptadil in patients hospitalized for COVID-19 at high risk of developing ARDS. METHODS: This multicenter, placebo-controlled, double-blinded, randomized trial with 132 adult patients hospitalized for COVID-19 and at high risk for ARDS (adapted early acute lung injury score ≥ 2 points) is conducted in five public hospitals in Europe. Key exclusion criteria are mechanical ventilation at baseline, need for intensive care at baseline, and severe hemodynamic instability. Patients are randomly allocated to either inhale 67 µg aviptadil or normal saline (three times a day for 10 days), in addition to standard care, stratified by center. The primary endpoint is time from hospitalization to clinical improvement, defined as either hospital discharge, or improvement of at least two levels on the nine-level scale for clinical status suggested by the World Health Organization. DISCUSSION: Treatment strategies for COVID-19 are still limited. In the context of upcoming new variants of SARS-CoV-2 and possible inefficacy of the available vaccines and antibody therapies, the investigation of alternative therapy options plays a crucial role in decreasing associated mortality and improving prognosis. Due to its unique immunomodulating properties also targeting the SARS-CoV-2 pathways, inhaled aviptadil may have the potential to prevent ARDS in COVID-19. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04536350 . Registered 02 September 2020.