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Abstract Misfolding of the cellular PrP (PrPc) protein causes prion disease, leading to neurodegenerative disorders in numerous mammalian species, including goats. A lack of PrPc induces complete resistance to prion disease. The aim of this work was to engineer Alpine goats carrying knockout (KO) alleles of PRNP, the PrPc-encoding gene, using CRISPR/Cas9-ribonucleoproteins and single-stranded donor oligonucleotides. The targeted region preceded the PRNP Ter mutation previously described in Norwegian goats. Genome editors were injected under the zona pellucida prior to the electroporation of 565 Alpine goat embryos/oocytes. A total of 122 two-cell-stage embryos were transferred to 46 hormonally synchronized recipient goats. Six of the goats remained pregnant and naturally gave birth to 10 offspring. Among the 10 newborns, eight founder animals carrying PRNP genome-edited alleles were obtained. Eight different mutated alleles were observed, including five inducing KO mutations. Three founders carried only genome-edited alleles and were phenotypically indistinguishable from their wild-type counterparts. Among them, one male carrying a one base pair insertion leading to a KO allele is currently used to rapidly extend a PRNP-KO line of Alpine goats for future characterization. In addition to KO alleles, a PRNP del6 genetic variant has been identified in one-third of founder animals. This new variant will be tested for its potential properties with respect to prion disease. Future studies will also evaluate the effects of genetic background on other characters associated with PRNP KO, as previously described in the Norwegian breed or other species.

Abstract Background In post-partum dairy cows, the energy needs to satisfy high milk production induces a status of more or less pronounced Negative Energy Balance (NEB). NEB associated with fat mobilization impairs reproductive function. In a companion paper, we described constitutive gene expression in the three main endometrial cell types (stromal, glandular and luminal epithelial cells) isolated by laser capture micro-dissection (LCM) showing the specificities of their transcriptomic profiles. This study investigates the specific impact of NEB on gene expression in these cells around 80 days after parturition at day 15 of the oestrus cycle and describes their specific response to NEB. Results Following the description of their constitutive expression, the transcriptome profiles obtained by RNA sequencing of the three cells types revealed that differences related to the severity of NEB altered mainly specific patterns of expression related to individual cell types. Number of differentially expressed genes between severe NEB (SNEB) and mild NEB (MNEB) cows was higher in ST than in LE and GE, respectively. SNEB was associated with differential expression of genes coding for proteins involved in metabolic processes and embryo-maternal interactions in ST. Under-expression of genes encoding proteins with functions related to cell structure was found in GE whereas genes encoding proteins participating in pro-inflammatory pathways were over-expressed. Genes associated to adaptive immunity were under-expressed in LE. Conclusion The severity of NEB after calving is associated with changes in gene expression around 80 days after parturition corresponding to the time of breeding. Specific alterations in GEs are associated with activation of pro-inflammatory mechanisms. Concomitantly, changes in the expression of genes encoding proteins involved in cell interactions and maternal recognition of pregnancy takes place in ST. The combination of these effects possibly altering the uterine environment and embryo maternal interactions may negatively influence the establishment of pregnancy.

Abstract Background A number of studies have examined mRNA expression profiles of bovine endometrium at estrus and around the peri-implantation period of pregnancy. However, to date, these studies have been performed on the whole endometrium which is a complex tissue. Consequently, the knowledge of cell-specific gene expression, when analysis performed with whole endometrium, is still weak and obviously limits the relevance of the results of gene expression studies. Thus, the aim of this study was to characterize specific transcriptome of the three main cell-types of the bovine endometrium at day-15 of the estrus cycle. Results In the RNA-Seq analysis, the number of expressed genes detected over 10 transcripts per million was 6622, 7814 and 8242 for LE, GE and ST respectively. ST expressed exclusively 1236 genes while only 551 transcripts were specific to the GE and 330 specific to LE. For ST, over-represented biological processes included many regulation processes and response to stimulus, cell communication and cell adhesion, extracellular matrix organization as well as developmental process. For GE, cilium organization, cilium movement, protein localization to cilium and microtubule-based process were the only four main biological processes enriched. For LE, over-represented biological processes were enzyme linked receptor protein signaling pathway, cell-substrate adhesion and circulatory system process. Conclusion The data show that each endometrial cell-type has a distinct molecular signature and provide a significantly improved overview on the biological process supported by specific cell-types. The most interesting result is that stromal cells express more genes than the two epithelial types and are associated with a greater number of pathways and ontology terms.

Abstract Background Pressurized Intra-Peritoneal Aerosol Chemotherapy (PIPAC) is an innovative treatment against peritoneal carcinomatosis. Doxorubicin is a common intra-venous chemotherapy used for peritoneal carcinomatosis and for PIPAC. This study evaluated the impact of increased PIPAC intraperitoneal pressure on the distribution and cell penetration of doxorubicin in a sheep model. Methods Doxorubicin was aerosolized using PIPAC into the peritoneal cavity of 6 ewes (pre-alpes breed): N = 3 with 12 mmHg intraperitoneal pressure (“group 12”) and N = 3 with 20 mmHg (“group 20”). Samples from peritoneum (N = 6), ovarian (N = 1), omentum (N = 1) and caecum (N = 1) were collected for each ewe. The number of doxorubicin positive cells was determined using the ratio between doxorubicine fluorescence-positive cell nuclei (DOXO+) over total number of DAPI positive cell nuclei (DAPI+). Penetration depth (μm) was defined as the distance between the luminal surface and the location of the deepest DOXO+ nuclei over the total number of cell nuclei that were stained with DAPI. Penetration depth (μm) was defined as the distance between the luminal surface and the location of the deepest DOXO+ nuclei. Results DOXO+ nuclei were identified in 87% of samples. All omental samples, directly localized in front of the nebulizer head, had 100% DOXO+ nuclei whereas very few nuclei were DOXO+ for caecum. Distribution patterns were not different between the two groups but penetration depth in ovary and caecum samples was significantly deeper in group 20. Conclusions This study showed that applying a higher intra-peritoneal pressure during PIPAC treatment leads to a deeper penetration of doxorubicin in ovarian and caecum but does not affect distribution patterns.

Abstract Background Inter-facility transport of patients with acute respiratory distress syndrome (ARDS) in the prone position (PP) is a high-risk situation, compared to other strategies. We aimed to quantify the prevalence of complications during transport in PP, compared to transports with veno-venous extracorporeal membrane oxygenation (VV-ECMO) or in the supine position (SP). Methods We performed a retrospective, single center cohort study in Lyon university hospital, France. We included patients ≥ 16 years with ARDS (Berlin definition) transported to an ARDS referral center between 01/12/2016 and 31/12/2021. We compared patients transported in PP, to those transported in SP without VV-ECMO, and those transported with VV-ECMO (in SP), by a multidisciplinary and specialized medical transport team, including an emergency physician and an intensivist. The primary outcome was the rate of transport-related complications (hypoxemia, hypotension, cardiac arrest, cannula or tube dislodgement) in each study groups, compared using a Fisher test. Results One hundred thirty-four patients were enrolled (median PaO2/FiO2 70 [58–82] mmHg), of which 11 (8%) were transported in PP, 44 (33%) with VV-ECMO, and 79 (59%) in SP. The most frequent risk factor for ARDS in the PP group was bacterial pneumonitis, and viral pneumonitis in the other 2 groups. Transport-related complications occurred in 36% (n = 4) of transports in PP, compared to 39% (n = 30) in SP and 14% (n = 6) with VV-ECMO, respectively (p = 0.33). VV-ECMO implantation after transport was not different between SP and PP patients (n = 7, 64% vs. n = 31, 39%, p = 0.19). Conclusions In the context of a specialized multi-disciplinary ARDS transport team, transport-related complication rates were similar between patients transported in PP and SP, while there was a trend of lower rates in patients transported with VV-ECMO.

Abstract Background Respiratory mechanics is a key element to monitor mechanically ventilated patients and guide ventilator settings. Besides the usual basic assessments, some more complex explorations may allow to better characterize patients’ respiratory mechanics and individualize ventilation strategies. These advanced respiratory mechanics assessments including esophageal pressure measurements and complete airway closure detection may be particularly relevant in critically ill obese patients. This study aimed to comprehensively assess respiratory mechanics in obese and non-obese ICU patients with or without ARDS and evaluate the contribution of advanced respiratory mechanics assessments compared to basic assessments in these patients. Methods All intubated patients admitted in two ICUs for any cause were prospectively included. Gas exchange and respiratory mechanics including esophageal pressure and end-expiratory lung volume (EELV) measurements and low-flow insufflation to detect complete airway closure were assessed in standardized conditions (tidal volume of 6 mL kg−1 predicted body weight (PBW), positive end-expiratory pressure (PEEP) of 5 cmH2O) within 24 h after intubation. Results Among the 149 analyzed patients, 52 (34.9%) were obese and 90 (60.4%) had ARDS (65.4% and 57.8% of obese and non-obese patients, respectively, p = 0.385). A complete airway closure was found in 23.5% of the patients. It was more frequent in obese than in non-obese patients (40.4% vs 14.4%, p

Abstract 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.

Abstract Background Airway opening pressure (AOP) detection and measurement are essential for assessing respiratory mechanics and adapting ventilation. We propose a novel approach for AOP assessment during volume assist control ventilation at a usual constant-flow rate of 60 L/min. Objectives To validate the conductive pressure (P cond) method, which compare the P cond—defined on the airway pressure waveform as the difference between the airway pressure level at which an abrupt change in slope occurs at the beginning of insufflation and PEEP—to resistive pressure for AOP detection and measurement, and to compare its respiratory and hemodynamic tolerance to the standard low-flow insufflation method. Methods The proof-of-concept of the P cond method was assessed on mechanical (lung simulator) and physiological (cadavers) bench models. Its diagnostic performance was evaluated in 213 patients, using the standard low-flow insufflation method as a reference. In 45 patients, the respiratory and hemodynamic tolerance of the P cond method was compared with the standard low-flow method. Measurements and main results Bench assessments validated the P cond method proof-of-concept. Sensitivity and specificity of the P cond method for AOP detection were 93% and 91%, respectively. AOP obtained by P cond and standard low-flow methods strongly correlated (r = 0.84, p

Abstract Background Baricitinib has shown efficacy in hospitalized patients with COVID-19, but no placebo-controlled trials have focused specifically on severe/critical COVID, including vaccinated participants. Methods Bari-SolidAct is a phase-3, multicentre, randomised, double-blind, placebo-controlled trial, enrolling participants from June 3, 2021 to March 7, 2022, stopped prematurely for external evidence. Patients with severe/critical COVID-19 were randomised to Baricitinib 4 mg once daily or placebo, added to standard of care. The primary endpoint was all-cause mortality within 60 days. Participants were remotely followed to day 90 for safety and patient related outcome measures. Results Two hundred ninety-nine patients were screened, 284 randomised, and 275 received study drug or placebo and were included in the modified intent-to-treat analyses (139 receiving baricitinib and 136 placebo). Median age was 60 (IQR 49–69) years, 77% were male and 35% had received at least one dose of SARS-CoV2 vaccine. There were 21 deaths at day 60 in each group, 15.1% in the baricitinib group and 15.4% in the placebo group (adjusted absolute difference and 95% CI − 0.1% [− 8·3 to 8·0]). In sensitivity analysis censoring observations after drug discontinuation or rescue therapy (tocilizumab/increased steroid dose), proportions of death were 5.8% versus 8.8% (− 3.2% [− 9.0 to 2.7]), respectively. There were 148 serious adverse events in 46 participants (33.1%) receiving baricitinib and 155 in 51 participants (37.5%) receiving placebo. In subgroup analyses, there was a potential interaction between vaccination status and treatment allocation on 60-day mortality. In a subsequent post hoc analysis there was a significant interaction between vaccination status and treatment allocation on the occurrence of serious adverse events, with more respiratory complications and severe infections in vaccinated participants treated with baricitinib. Vaccinated participants were on average 11 years older, with more comorbidities. Conclusion This clinical trial was prematurely stopped for external evidence and therefore underpowered to conclude on a potential survival benefit of baricitinib in severe/critical COVID-19. We observed a possible safety signal in vaccinated participants, who were older with more comorbidities. Although based on a post-hoc analysis, these findings warrant further investigation in other trials and real-world studies. Trial registration Bari-SolidAct is registered at NCT04891133 (registered May 18, 2021) and EUClinicalTrials.eu ( 2022-500385-99-00 ).

Abstract Background In the context of COVID-19 pandemic, antifungal overuse may have occurred in our hospitals as it has been previously reported for antibacterials. Methods To investigate the impact of COVID-19 on antifungal consumption, a multicenter retrospective study including four medical sites and 14 intensive care units (ICU) was performed. Antifungal consumption and incidences of invasive fungal diseases before and during COVID-19 pandemic, for non-COVID-19 patients and COVID-19 patients, were described. Results An increase in voriconazole consumption was observed in 2020 compared with 2019 for both the whole hospital and the ICU (+ 40.3% and + 63.7%, respectively), whereas the incidence of invasive aspergillosis significantly increased in slightly lower proportions in the ICU (+ 46%). Caspofungin consumption also increased in 2020 compared to 2019 for both the whole hospital and the ICU (+ 34.9% and + 17.0%, respectively) with an increased incidence of invasive candidiasis in the whole hospital and the ICU but in lower proportions (+ 20.0% and + 10.9%, respectively). Conclusions We observed an increased consumption of antifungals including voriconazole and caspofungin in our hospital during the COVID-19 pandemic and explained in part by an increased incidence of invasive fungal diseases in COVID-19 patients. These results are of utmost importance as it raises concern about the urgent need for appropriate antifungal stewardship activities to control antifungal consumption.

Abstract Background Spontaneous breathing trials are performed in critically ill intubated patients in order to assess readiness to be weaned from mechanical ventilation. In patients with difficult weaning (i.e. not extubated after their first SBT), performing SBT using pressure support with or without positive end-expiratory pressure or using T-piece is debated. As ventilatory support during SBT is greater on pressure support than on T-piece and as positive end-expiratory pressure can prevent weaning-induced pulmonary oedema, we hypothesized that their combination and large use of post-extubation non-invasive ventilation may shorten the time until successful extubation as compared with T-piece, without increasing the rate of reintubation. Methods SBT-ICU is a monocentric prospective open labelled, randomized controlled superiority trial comparing two mechanical ventilation weaning strategies; i.e. daily spontaneous breathing trials using pressure support with positive end-expiratory pressure or T-piece. The primary outcome will be time until successful extubation (defined by as extubation, without reintubation or death within the seven following days). Discussion This paper describes the protocol of the SBT-ICU trial. Enrolment of patients in the study is ongoing. Trial registration ClinicalTrials.gov NCT03861117. Registered on March 1, 2019, before the beginning of inclusion.

Abstract Background Cardiopulmonary resuscitation (CPR) decreases lung volume below the functional residual capacity and can generate intrathoracic airway closure. Conversely, large insufflations can induce thoracic distension and jeopardize circulation. The capnogram (CO2 signal) obtained during continuous chest compressions can reflect intrathoracic airway closure, and we hypothesized here that it can also indicate thoracic distension. Objectives To test whether a specific capnogram may identify thoracic distension during CPR and to assess the impact of thoracic distension on gas exchange and hemodynamics. Methods (1) In out-of-hospital cardiac arrest patients, we identified on capnograms three patterns: intrathoracic airway closure, thoracic distension or regular pattern. An algorithm was designed to identify them automatically. (2) To link CO2 patterns with ventilation, we conducted three experiments: (i) reproducing the CO2 patterns in human cadavers, (ii) assessing the influence of tidal volume and respiratory mechanics on thoracic distension using a mechanical lung model and (iii) exploring the impact of thoracic distension patterns on different circulation parameters during CPR on a pig model. Measurements and main results (1) Clinical data: 202 capnograms were collected. Intrathoracic airway closure was present in 35%, thoracic distension in 22% and regular pattern in 43%. (2) Experiments: (i) Higher insufflated volumes reproduced thoracic distension CO2 patterns in 5 cadavers. (ii) In the mechanical lung model, thoracic distension patterns were associated with higher volumes and longer time constants. (iii) In six pigs during CPR with various tidal volumes, a CO2 pattern of thoracic distension, but not tidal volume per se, was associated with a significant decrease in blood pressure and cerebral perfusion. Conclusions During CPR, capnograms reflecting intrathoracic airway closure, thoracic distension or regular pattern can be identified. In the animal experiment, a thoracic distension pattern on the capnogram is associated with a negative impact of ventilation on blood pressure and cerebral perfusion during CPR, not predicted by tidal volume per se.

Abstract Background Fluid overload is associated with worse outcome in critically ill patients requiring continuous renal replacement therapy (CRRT). Net ultrafiltration (UFNET) allows precise control of the fluid removal but is frequently ceased due to hemodynamic instability episodes. However, approximately 50% of the hemodynamic instability episodes in ICU patients treated with CRRT are not associated with preload dependence (i.e., are not related to a decrease in cardiac preload), suggesting that volume removal is not responsible for these episodes of hemodynamic impairment. The use of advanced hemodynamic monitoring, comprising continuous cardiac output monitoring to repeatedly assess preload dependency, could allow securing UFNET to allow fluid balance control and prevent fluid overload. Methods The GO NEUTRAL trial is a multicenter, open-labeled, randomized, controlled, superiority trial with parallel groups and balanced randomization with a 1:1 ratio. The trial will enroll adult patients with acute circulatory failure treated with vasopressors and severe acute kidney injury requiring CRRT who already have been equipped with a continuous cardiac output monitoring device. After informed consent, patients will be randomized into two groups. The control group will receive protocolized fluid removal with an UFNET rate set to 0–25 ml h−1 between inclusion and H72 of inclusion. The intervention group will be treated with an UFNET rate set on the CRRT of at least 100 ml h−1 between inclusion and H72 of inclusion if hemodynamically tolerated based on a protocolized hemodynamic protocol aiming to adjust UFNET based on cardiac output, arterial lactate concentration, and preload dependence assessment by postural maneuvers, performed regularly during nursing rounds, and in case of a hemodynamic instability episode. The primary outcome of the study will be the cumulative fluid balance between inclusion and H72 of inclusion. Randomization will be generated using random block sizes and stratified based on fluid overload status at inclusion. The main outcome will be analyzed in the modified intention-to-treat population, defined as all alive patients at H72 of inclusion, based on their initial allocation group. Discussion We present in the present protocol all study procedures in regard to the achievement of the GO NEUTRAL trial, to prevent biased analysis of trial outcomes and improve the transparency of the trial result report. Enrollment of patients in the GO NEUTRAL trial has started on June 31, 2021, and is ongoing. Trial registration ClinicalTrials.gov NCT04801784. Registered on March 12, 2021, before the start of inclusion.

Abstract Background PEEP selection in severe COVID-19 patients under extracorporeal membrane oxygenation (ECMO) is challenging as no study has assessed the alveolar recruitability in this setting. The aim of the study was to compare lung recruitability and the impact of PEEP on lung aeration in moderate and severe ARDS patients with or without ECMO, using computed tomography (CT). Methods We conducted a two-center prospective observational case–control study in adult COVID-19-related patients who had an indication for CT within 72 h of ARDS onset in non-ECMO patients or within 72 h after ECMO onset. Ninety-nine patients were included, of whom 24 had severe ARDS under ECMO, 59 severe ARDS without ECMO and 16 moderate ARDS. Results Non-inflated lung at PEEP 5 cmH2O was significantly greater in ECMO than in non-ECMO patients. Recruitment induced by increasing PEEP from 5 to 15 cmH2O was not significantly different between ECMO and non-ECMO patients, while PEEP-induced hyperinflation was significantly lower in the ECMO group and virtually nonexistent. The median [IQR] fraction of recruitable lung mass between PEEP 5 and 15 cmH2O was 6 [4–10]%. Total superimposed pressure at PEEP 5 cmH2O was significantly higher in ECMO patients and amounted to 12 [11–13] cmH2O. The hyperinflation-to-recruitment ratio (i.e., a trade-off index of the adverse effects and benefits of PEEP) was significantly lower in ECMO patients and was lower than one in 23 (96%) ECMO patients, 41 (69%) severe non-ECMO patients and 8 (50%) moderate ARDS patients. Compliance of the aerated lung at PEEP 5 cmH2O corrected for PEEP-induced recruitment (CBABY LUNG) was significantly lower in ECMO patients than in non-ECMO patients and was linearly related to the logarithm of the hyperinflation-to-recruitment ratio. Conclusions Lung recruitability of COVID-19 pneumonia is not significantly different between ECMO and non-ECMO patients, with substantial interindividual variations. The balance between hyperinflation and recruitment induced by PEEP increase from 5 to 15 cmH2O appears favorable in virtually all ECMO patients, while this PEEP level is required to counteract compressive forces leading to lung collapse. CBABY LUNG is significantly lower in ECMO patients, independently of lung recruitability.

Abstract Background Acute respiratory distress syndrome (ARDS) is a severe complication of COVID-19 pneumonia, with a mortality rate amounting to 34–50% in moderate and severe ARDS, and is associated with prolonged duration of invasive mechanical ventilation. Such as in non-COVID ARDS, harmful mechanical ventilation settings might be associated with worse outcomes. Reducing the tidal volume down to 4 mL kg−1 of predicted body weight (PBW) to provide ultra-low tidal volume ventilation (ULTV) is an appealing technique to minimize ventilator-inducted lung injury. Furthermore, in the context of a worldwide pandemic, it does not require any additional material and consumables and may be applied in low- to middle-income countries. We hypothesized that ULTV without extracorporeal circulation is a credible option to reduce COVID-19-related ARDS mortality and duration of mechanical ventilation. Methods The VT4COVID study is a randomized, multi-centric prospective open-labeled, controlled superiority trial. Adult patients admitted in the intensive care unit with COVID-19-related mild to severe ARDS defined by a PaO2/FiO2 ratio ≤ 150 mmHg under invasive mechanical ventilation for less than 48 h, and consent to participate to the study will be eligible. Patients will be randomized into two balanced parallels groups, at a 1:1 ratio. The control group will be ventilated with protective ventilation settings (tidal volume 6 mL kg−1 PBW), and the intervention group will be ventilated with ULTV (tidal volume 4 mL kg−1 PBW). The primary outcome is a composite score based on 90-day all-cause mortality as a prioritized criterion and the number of ventilator-free days at day 60 after inclusion. The randomization list will be stratified by site of recruitment and generated using random blocks of sizes 4 and 6. Data will be analyzed using intention-to-treat principles. Discussion The purpose of this manuscript is to provide primary publication of study protocol to prevent selective reporting of outcomes, data-driven analysis, and to increase transparency. Enrollment of patients in the study is ongoing. Trial registration ClinicalTrials.gov NCT04349618 . Registered on April 16, 2020

Abstract Background Differences in physiology of ARDS have been described between COVID-19 and non-COVID-19 patients. This study aimed to compare initial values and longitudinal changes in respiratory system compliance (C RS), oxygenation parameters and ventilatory ratio (VR) in patients with COVID-19 and non-COVID-19 pulmonary ARDS matched on oxygenation. Methods 135 patients with COVID-19 ARDS from two centers were included in a physiological study; 767 non-COVID-19 ARDS from a clinical trial were used for the purpose of at least 1:2 matching. A propensity-matching was based on age, severity score, oxygenation, positive end-expiratory pressure (PEEP) and pulmonary cause of ARDS and allowed to include 112 COVID-19 and 198 non-COVID pulmonary ARDS. Results The two groups were similar on initial oxygenation. COVID-19 patients had a higher body mass index, higher C RS at day 1 (median [IQR], 35 [28–44] vs 32 [26–38] ml cmH2O−1, p = 0.037). At day 1, C RS was correlated with oxygenation only in non-COVID-19 patients; 61.6% and 68.2% of COVID-19 and non-COVID-19 pulmonary ARDS were still ventilated at day 7 (p = 0.241). Oxygenation became lower in COVID-19 than in non-COVID-19 patients at days 3 and 7, while C RS became similar. VR was lower at day 1 in COVID-19 than in non-COVID-19 patients but increased from day 1 to 7 only in COVID-19 patients. VR was higher at days 1, 3 and 7 in the COVID-19 patients ventilated using heat and moisture exchangers compared to heated humidifiers. After adjustment on PaO2/FiO2, PEEP and humidification device, C RS and VR were found not different between COVID-19 and non-COVID-19 patients at day 7. Day-28 mortality did not differ between COVID-19 and non-COVID-19 patients (25.9% and 23.7%, respectively, p = 0.666). Conclusions For a similar initial oxygenation, COVID-19 ARDS initially differs from classical ARDS by a higher C RS, dissociated from oxygenation. C RS become similar for patients remaining on mechanical ventilation during the first week of evolution, but oxygenation becomes lower in COVID-19 patients. Trial registration: clinicaltrials.gov NCT04385004

Abstract Background There is wide variability between intensivists in the decisions to forgo life-sustaining treatment (DFLST). Advance directives (ADs) allow patients to communicate their end-of-life wishes to physicians. We assessed whether ADs reduced variability in DFLSTs between intensivists. Methods We conducted a multicenter, prospective, simulation study. Eight patients expressed their wishes in ADs after being informed about DFLSTs by an intensivist-investigator. The participating intensivists answered ten questions about the DFLSTs of each patient in two scenarios, referring to patients’ characteristics without ADs (round 1) and then with (round 2). DFLST score ranged from 0 (no-DFLST) to 10 (DFLST for all questions). The main outcome was variability in DFLSTs between intensivists, expressed as relative standard deviation (RSD). Results A total of 19,680 decisions made by 123 intensivists from 27 ICUs were analyzed. The DFLST score was higher with ADs than without (6.02 95% CI [5.85; 6.19] vs 4.92 95% CI [4.75; 5.10], p

Abstract Background Predicting fluid responsiveness may help to avoid unnecessary fluid administration during acute respiratory distress syndrome (ARDS). The aim of this study was to evaluate the diagnostic performance of the following methods to predict fluid responsiveness in ARDS patients under protective ventilation in the prone position: cardiac index variation during a Trendelenburg maneuver, cardiac index variation during an end-expiratory occlusion test, and both pulse pressure variation and change in pulse pressure variation from baseline during a tidal volume challenge by increasing tidal volume (VT) to 8 ml.kg-1. Methods This study is a prospective single-center study, performed in a medical intensive care unit, on ARDS patients with acute circulatory failure in the prone position. Patients were studied at baseline, during a 1-min shift to the Trendelenburg position, during a 15-s end-expiratory occlusion, during a 1-min increase in VT to 8 ml.kg-1, and after fluid administration. Fluid responsiveness was deemed present if cardiac index assessed by transpulmonary thermodilution increased by at least 15% after fluid administration. Results There were 33 patients included, among whom 14 (42%) exhibited cardiac arrhythmia at baseline and 15 (45%) were deemed fluid-responsive. The area under the receiver operating characteristic (ROC) curve of the pulse contour-derived cardiac index change during the Trendelenburg maneuver and the end-expiratory occlusion test were 0.90 (95% CI, 0.80–1.00) and 0.65 (95% CI, 0.46–0.84), respectively. An increase in cardiac index ≥ 8% during the Trendelenburg maneuver enabled diagnosis of fluid responsiveness with sensitivity of 87% (95% CI, 67–100), and specificity of 89% (95% CI, 72–100). The area under the ROC curve of pulse pressure variation and change in pulse pressure variation during the tidal volume challenge were 0.52 (95% CI, 0.24–0.80) and 0.59 (95% CI, 0.31–0.88), respectively. Conclusions Change in cardiac index during a Trendelenburg maneuver is a reliable test to predict fluid responsiveness in ARDS patients in the prone position, while neither change in cardiac index during end-expiratory occlusion, nor pulse pressure variation during a VT challenge reached acceptable predictive performance to predict fluid responsiveness in this setting. Trial registration ClinicalTrials.gov, NCT01965574 . Registered on 16 October 2013. The trial was registered 6 days after inclusion of the first patient.