Silencing of amygdala circuits during sepsis prevents the development of anxiety-related behaviours.

Sepsis is a life-threatening condition induced by a deregulated host response to severe infection. Post-sepsis syndrome includes long-term psychiatric disorders, such as persistent anxiety and post-traumatic stress disorder, whose neurobiological mechanisms remain unknown. Using a reference mouse model of sepsis, we showed that mice that recovered from sepsis further developed anxiety-related behaviours associated with an exaggerated fear memory. In the brain, sepsis induced an acute pathological activation of a specific neuronal population of the central nucleus of the amygdala, which projects to the ventral bed nucleus of the stria terminalis. Using viral-genetic circuit tracing and in vivo calcium imaging, we observed that sepsis induced persistent changes in the connectivity matrix and in the responsiveness of these central amygdala neurons projecting to the ventral bed nucleus of the stria terminalis. The transient and targeted silencing of this subpopulation only during the acute phase of sepsis with a viral pharmacogenetic approach, or with the anti-epileptic and neuroprotective drug levetiracetam, prevented the subsequent development of anxiety-related behaviours. Specific inhibition of brain anxiety and fear circuits during the sepsis acute phase constitutes a preventive approach to preclude the post-infection psychiatric outcomes.

Valproic acid as adjuvant treatment for convulsive status epilepticus: a randomised clinical trial.

BACKGROUND: Generalised convulsive status epilepticus (GCSE) is a medical emergency. Guidelines recommend a stepwise strategy of benzodiazepines followed by a second-line anti-seizure medicine (ASM). However, GCSE is uncontrolled in 20-40% patients and is associated with protracted hospitalisation, disability, and mortality. The objective was to determine whether valproic acid (VPA) as complementary treatment to the stepwise strategy improves the outcomes of patients with de novo established GCSE. METHODS: This was a multicentre, double-blind, randomised controlled trial in 244 adults admitted to intensive care units for GCSE in 16 French hospitals between 2013 and 2018. Patients received standard care of benzodiazepine and a second-line ASM (except VPA). Intervention patients received a 30 mg/kg VPA loading dose, then a 1 mg/kg/h 12 h infusion, whilst the placebo group received an identical intravenous administration of 0.9% saline as a bolus and continuous infusion. Primary outcome was proportion of patients discharged from hospital by day 15. The secondary outcomes were seizure control, adverse events, and cognition at day 90. RESULTS: A total of 126 (52%) and 118 (48%) patients were included in the VPA and placebo groups. 224 (93%) and 227 (93%) received a first-line and a second-line ASM before VPA or placebo infusion. There was no between-group difference for patients hospital-discharged at day 15 [VPA, 77 (61%) versus placebo, 72 (61%), adjusted relative risk 1.04; 95% confidence interval (0.89-1.19); p = 0.58]. There were no between-group differences for secondary outcomes. CONCLUSIONS: VPA added to the recommended strategy for adult GCSE is well tolerated but did not increase the proportion of patients hospital-discharged by day 15. TRIAL REGISTRATION NO: NCT01791868 (ClinicalTrials.gov registry), registered: 15 February 2012.

Quantitative analysis of early-stage EEG reactivity predicts awakening and recovery of consciousness in patients with severe brain injury.

BACKGROUND: Decisions of withdrawal of life-sustaining therapy for patients with severe brain injury are often based on prognostic evaluations such as analysis of electroencephalography (EEG) reactivity (EEG-R). However, EEG-R usually relies on visual assessment, which requires neurophysiological expertise and is prone to inter-rater variability. We hypothesised that quantitative analysis of EEG-R obtained 3 days after patient admission can identify new markers of subsequent awakening and consciousness recovery. METHODS: In this prospective observational study of patients with severe brain injury requiring mechanical ventilation, quantitative EEG-R was assessed using standard 11-lead EEG with frequency-based (power spectral density) and functional connectivity-based (phase-lag index) analyses. Associations between awakening in the intensive care unit (ICU) and reactivity to auditory and nociceptive stimulations were assessed with logistic regression. Secondary outcomes included in-ICU mortality and 3-month Coma Recovery Scale-Revised (CRS-R) score. RESULTS: Of 116 patients, 86 (74%) awoke in the ICU. Among quantitative EEG-R markers, variation in phase-lag index connectivity in the delta frequency band after noise stimulation was associated with awakening (adjusted odds ratio=0.89, 95% confidence interval: 0.81-0.97, P=0.02 corrected for multiple tests), independently of age, baseline severity, and sedation. This new marker was independently associated with improved 3-month CRS-R (adjusted ß=-0.16, standard error 0.075, P=0.048), but not with mortality (adjusted odds ratio=1.08, 95% CI: 0.99-1.18, P=0.10). CONCLUSIONS: An early-stage quantitative EEG-R marker was independently associated with awakening and 3-month level of consciousness in patients with severe brain injury. This promising marker based on functional connectivity will need external validation before potential integration into a multimodal prognostic model.

Acute Distress Respiratory Syndrome After Subarachnoid Hemorrhage: Incidence and Impact on the Outcome in a Large Multicenter, Retrospective Cohort.

BACKGROUND: Respiratory complications are frequently reported after aneurismal subarachnoid hemorrhage (aSAH), even if their association with outcome remains controversial. Acute respiratory distress syndrome (ARDS) is one of the most severe pulmonary complications after aSAH, with a reported incidence ranging from 11 to 50%. This study aims to assess in a large cohort of aSAH patients, during the first week after an intensive care unit (ICU) admission, the incidence of ARDS defined according to the Berlin criteria and its effect on outcome. METHODS: This is a multicentric, retrospective cohort study in 3 European intensive care units. We collected data between January 2009 and December 2017. We included adult patients (≥ 18 years) with a diagnosis of aSAH admitted to the ICU. RESULTS: A total of 855 patients fulfilled the inclusion criteria. ARDS was assessable in 851 patients. The cumulative incidence of ARDS was 2.2% on the first day since ICU admission, 3.2% on day three, and 3.6% on day seven. At the univariate analysis, ARDS was associated with a poor outcome (p = 0.005) at ICU discharge, and at the multivariable analysis, patients with ARDS showed a worse neurological outcome (Odds ratio = 3.00, 95% confidence interval 1.16-7.72; p = 0.023). CONCLUSIONS: ARDS has a low incidence in the first 7 days of ICU stay after aSAH, but it is associated with worse outcome.

Association Between Anxiety and New Organ Failure, Independently of Critical Illness Severity and Respiratory Status: A Prospective Multicentric Cohort Study.

OBJECTIVES: Anxiety results from the anticipation of a threat and might be associated with poor outcome in the critically ill. This study aims at showing that anxiety at admission in critically ill patients is associated with new organ failure over the first 7 days of ICU hospitalization independently of baseline organ failure at admission. DESIGN: Prospective multicenter cohort study. SETTING: Three mixed ICU from April 2014 to December 2017. PATIENTS: Coma-, delirium-, and invasive mechanical ventilation-free patients admitted to the ICU were included. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: "State anxiety" was assessed using the state component of the State-Trait Anxiety Inventory State. Severity of illness was measured using Simplified Acute Physiology Score II and Sequential Organ Failure Assessment scores. Primary endpoint was a composite of occurrence of death or new organ failure in the first 7 days after admission. Three hundred ninety-one patients were included; 159 of 391 women (40.7%); median age 63 years (49-74 yr); median Simplified Acute Physiology Score II 28 (19-37). Two hundred three out of 391 patients (51.9%) reported moderate to severe anxiety (State-Trait Anxiety Inventory State ≥ 40). One hundred two out of 391 patients (26.1%) developed a new organ failure. After adjustment to Simplified Acute Physiology Score II and Sequential Organ Failure Assessment, State-Trait Anxiety Inventory State greater than or equal to 40 was associated with the primary endpoint (odds ratio, 1.94; 95% CI, 1.18-3.18; p = 0.009) and respiratory failure. In post hoc analysis, State-Trait Anxiety Inventory State greater than or equal to 40 was associated with new organ failure independently and notably of respiratory status at admission (dyspnea-Visual Analogic Scale and PaCO2 ≥ 45 mm Hg). CONCLUSIONS: Moderate to severe anxiety at ICU admission is associated with early occurrence of new organ failure in critically ill patients, independently of respiratory status and severity of critical illness. The causality link could be addressed in an interventional trial.

Brainstem dysfunction in critically ill patients.

The brainstem conveys sensory and motor inputs between the spinal cord and the brain, and contains nuclei of the cranial nerves. It controls the sleep-wake cycle and vital functions via the ascending reticular activating system and the autonomic nuclei, respectively. Brainstem dysfunction may lead to sensory and motor deficits, cranial nerve palsies, impairment of consciousness, dysautonomia, and respiratory failure. The brainstem is prone to various primary and secondary insults, resulting in acute or chronic dysfunction. Of particular importance for characterizing brainstem dysfunction and identifying the underlying etiology are a detailed clinical examination, MRI, neurophysiologic tests such as brainstem auditory evoked potentials, and an analysis of the cerebrospinal fluid. Detection of brainstem dysfunction is challenging but of utmost importance in comatose and deeply sedated patients both to guide therapy and to support outcome prediction. In the present review, we summarize the neuroanatomy, clinical syndromes, and diagnostic techniques of critical illness-associated brainstem dysfunction for the critical care setting.

Age-related cognitive impairment is associated with long-term neuroinflammation and oxidative stress in a mouse model of episodic systemic inflammation.

BACKGROUND: Microglia function is essential to maintain the brain homeostasis. Evidence shows that aged microglia are primed and show exaggerated response to acute inflammatory challenge. Systemic inflammation signals to the brain inducing changes that impact cognitive function. However, the mechanisms involved in age-related cognitive decline associated to episodic systemic inflammation are not completely understood. The aim of this study was to identify neuropathological features associated to age-related cognitive decline in a mouse model of episodic systemic inflammation. METHODS: Young and aged Swiss mice were injected with low doses of LPS once a week for 6 weeks to induce episodic systemic inflammation. Sickness behavior, inflammatory markers, and neuroinflammation were assessed in different phases of systemic inflammation in young and aged mice. Behavior was evaluated long term after episodic systemic inflammation by open field, forced swimming, object recognition, and water maze tests. RESULTS: Episodic systemic inflammation induced systemic inflammation and sickness behavior mainly in aged mice. Systemic inflammation induced depressive-like behavior in both young and aged mice. Memory and learning were significantly affected in aged mice that presented lower exploratory activity and deficits in episodic and spatial memories, compared to aged controls and to young after episodic systemic inflammation. Systemic inflammation induced acute microglia activation in young mice that returned to base levels long term after episodic systemic inflammation. Aged mice presented dystrophic microglia in the hippocampus and entorhinal cortex at basal level and did not change morphology in the acute response to SI. Regardless of their dystrophic microglia, aged mice produced higher levels of pro-inflammatory (IL-1ß and IL-6) as well as pro-resolution (IL-10 and IL-4) cytokines in the brain. Also, higher levels of Nox2 expression, oxidized proteins and lower antioxidant defenses were found in the aged brains compared to the young after episodic systemic inflammation. CONCLUSIONS: Our data show that aged mice have increased susceptibility to episodic systemic inflammation. Aged mice that showed cognitive impairments also presented higher oxidative stress and abnormal production of cytokines in their brains. These results indicate that a neuroinflammation and oxidative stress are pathophysiological mechanisms of age-related cognitive impairments.

Evaluation of Reperfusion Pulmonary Edema by Extravascular Lung Water Measurements After Pulmonary Endarterectomy.

OBJECTIVES: Reperfusion pulmonary edema is a specific complication of pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension. Extravascular lung water measurement may be valuable for diagnosing reperfusion pulmonary edema. The primary objective of this study was to describe and assess the clinical significance of extravascular lung water variations after pulmonary endarterectomy. DESIGN: Prospective observational study. SETTING: Nineteen-bed cardiothoracic ICU. PATIENTS: Consecutive patients who were hemodynamically stable after pulmonary endarterectomy were divided into two groups based on whether their preoperative pulmonary vascular resistance indicated severe or nonsevere chronic thromboembolic pulmonary hypertension (> 900 or ≤ 900 dynes·s/cm, respectively). INTERVENTIONS: Hemodynamic variables obtained by right heart catheterization and transpulmonary thermodilution measurements were recorded 1 hour, 1 day, and 2 days after pulmonary endarterectomy. Extravascular lung water was indexed to predicted body weight (EVLWPBW). MEASUREMENTS AND MAIN RESULTS: We studied 31 patients. Overall, 26 patients (84%) experienced reperfusion pulmonary edema during the first 72 hours after pulmonary endarterectomy. EVLWPBW significantly increased between the first hour after pulmonary endarterectomy and day 2 (10.2 ± 2.6 vs 11.4 ± 3.6; p = 0.03). EVLWPBW measured at the first hour after pulmonary endarterectomy is closely associated with reperfusion pulmonary edema occurrence in the next 48 hours (area under the receiver-operating characteristics curve = 0.88 ± 0.07). EVLWPBW correlated with duration of mechanical ventilation (ρ = 0.59; p < 0.0001) and ICU stay (ρ = 0.52; p < 0.0001). Patients with severe chronic thromboembolic pulmonary hypertension (n = 15) had higher EVLWPBW values at day 2 compared with those without (n = 16) (13.2 ± 3.6 vs 9.7 ± 2.7 mL/kg; p = 0.004). Cardiac output was measured simultaneously by pulmonary artery catheter and aortic transpulmonary thermodilution on 92 occasions; agreement was good, with a bias of 0.50 ± 0.95 L/min (95% CI, -1.36-2.36). CONCLUSIONS: Accurate extravascular lung water measurements were obtained after pulmonary endarterectomy. Extravascular lung water may prove valuable for diagnosing reperfusion pulmonary edema after pulmonary endarterectomy and had prognostic value. Extravascular lung water values were significantly higher in patients with severe compared with nonsevere chronic thromboembolic pulmonary hypertension.

Neuroanatomy of sepsis-associated encephalopathy.

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2017. Other selected articles can be found online at http://ccforum.com/series/annualupdate2017 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901 .Originally published in the Annual Update in Intensive Care and Emergency Medicine 2017. The number of authors differs in the two versions due to constraints regarding the number of authors in the Annual Update in Intensive Care and Emergency Medicine. In the Annual Update version of the review, the three senior authors appear in the acknowledgement section. In the Critical Care version, these three senior authors appear as full authors of the manuscript. All authors helped draft and revise the manuscript for critical intellectual content.

Immune quiescence of the brain is set by astroglial connexin 43.

In the normal brain, immune cell trafficking and immune responses are strictly controlled and limited. This unique homeostatic equilibrium, also called brain immune quiescence, is crucial to maintaining proper brain functions and is altered in various pathological processes, from chronic immunopathological disorders to cognitive and psychiatric impairments. To date, the precise nature of factors regulating the brain/immune system interrelationship is poorly understood. In the present study, we demonstrate that one of these regulating factors is Connexin 43 (Cx43), a gap junction protein highly expressed by astrocytes at the blood-brain barrier (BBB) interface. We show that, by setting the activated state of cerebral endothelium, astroglial Cx43 controls immune recruitment as well as antigen presentation mechanisms in the mouse brain. Consequently, in the absence of astroglial Cx43, recruited immune cells elaborate a specific humoral autoimmune response against the von Willebrand factor A domain-containing protein 5a, an extracellular matrix protein of the brain. Altogether, our results demonstrate that Cx43 is a new astroglial factor promoting the immune quiescence of the brain.

Experimental and clinical evidences for glucose control in intensive care: is infused glucose the key point for study interpretation?

Stress-induced hyperglycemia has been considered an adaptive mechanism to stress up to the first intensive insulin therapy trial, which showed a 34% reduction in relative risk of in-hospital mortality when normalizing blood glucose levels. Further trials had conflicting results and, at present, stress-induced hyperglycemia management remains non-consensual. These findings could be explained by discrepancies in trials, notably regarding the approach to treat hyperglycemia: high versus restrictive caloric intake. Stress-induced hyperglycemia is a frequent complication during intensive care unit stay and is associated with a higher mortality. It results from an imbalance between insulin and counter-regulatory hormones, increased neoglucogenesis, and the cytokine-induced insulin-resistant state of tissues. In this review, we summarize detrimental effects of hyperglycemia on organs in the critically ill (peripheric and central nervous, liver, immune system, kidney, and cardiovascular system). Finally, we show clinical and experimental evidence of potential benefits from glucose and insulin administration, notably on metabolism, immunity, and the cardiovascular system.

Association of Lack of Fear of Dying With New Organ Failure: Results of a Multicenter Prospective Cohort Study.

BACKGROUND: Patients' anxiety on intensive care unit (ICU) admission is associated with subsequent deterioration. OBJECTIVE: To assess whether patients' fears/anxiety are predictive of new organ failure within 7 days of ICU admission. METHODS: In a prospective 3-center cohort study of non-comatose patients without delirium or invasive mechanical ventilation, 9 specific fears were evaluated through yes/no questions. Illness severity was assessed using the Simplified Acute Physiology Score II (SAPS II) and the Sequential Organ Failure Assessment (SOFA). Intensity of acute and chronic anxiety was assessed with the state and trait components of the State-Trait Anxiety Inventory (STAI). Patients were followed up for 7 days. RESULTS: From April 2014 to December 2017, 373 patients (median [IQR] age, 63 [48-74] years; 152 [40.8%] women; median (IQR) SAPS II, 27 [19-37]) were included. Feelings of vulnerability and fear of dying were reported by 203 (54.4%) and 172 (46.1%) patients, respectively. The STAI-State score was 40 or greater in 192 patients (51.5%). Ninety-four patients (25.2%) had new organ failure. Feelings of vulnerability (odds ratio, 1.96 [95% CI, 1.12-3.43]; P=.02) and absence of fear of dying (odds ratio, 2.38 [95% CI, 1.37-4.17]; P=.002) were associated with new organ failure after adjustment for STAI-State score (≥40), SAPS II, and SOFA score. CONCLUSION: Absence of fear of dying is associated with new organ failure within the first 7 days after ICU admission. Fear of dying may protect against subsequent deterioration by mobilizing patients' homeostatic resources. ClinicalTrials.gov Identifier: NCT02355626.

A randomized clinical trial to evaluate the effect of post-intensive care multidisciplinary consultations on mortality and the quality of life at 1 year.

PURPOSE: Critical illness is associated with long-term increased mortality and impaired quality of life (QoL). We assessed whether multidisciplinary consultations would improve outcome at 12 months (M12) after intensive care unit (ICU) discharge. METHODS: We performed an open, multicenter, parallel-group, randomized clinical trial. Eligible are patients discharged alive from ICU in 11 French hospitals between 2012 and 2018. The intervention group had a multidisciplinary face-to-face consultation involving an intensivist, a psychologist, and a social worker at ICU discharge and then at M3 and M6 (optional). The control group had standard post-ICU follow-up. A consultation was scheduled at M12 for all patients. The QoL was assessed using the EuroQol-5 Dimensions-5 Level (Euro-QoL-5D-5L) which includes five dimensions (mobility, self-care, usual activities, pain, and anxiety/depression), each ranging from 1 to 5 (1: no, 2: slight, 3: moderate, 4: severe, and 5: extreme problems). The primary endpoint was poor clinical outcome defined as death or severe-to-extreme impairment of at least one EuroQoL-5D-5L dimension at M12. The information was collected by a blinded investigator by phone. Secondary outcomes were functional, psychological, and cognitive status at M12 consultation. RESULTS: 540 patients were included (standard, n = 272; multidisciplinary, n = 268). The risk for a poor outcome was significantly greater in the multidisciplinary group than in the standard group [adjusted odds ratio 1.49 (95% confidence interval, (1.04-2.13)]. Seventy-two (13.3%) patients died at M12 (standard, n = 32; multidisciplinary, n = 40). The functional, psychological, and cognitive scores at M12 did not statistically differ between groups. CONCLUSIONS: A hospital-based, face-to-face, intensivist-led multidisciplinary consultation at ICU discharge then at 3 and 6 months was associated with poor outcome 1 year after ICU.

Correction: Impact of a Postintensive Care Unit Multidisciplinary Follow-up on the Quality of Life (SUIVI-REA): Protocol for a Multicenter Randomized Controlled Trial.

[This corrects the article DOI: 10.2196/30496.].

Neuro-Inflammatory Response and Brain-Peripheral Crosstalk in Sepsis and Stroke.

Despite recent therapeutic advances, ischemic stroke is still a leading cause of death and disability. There is renewed attention on peripheral inflammatory signaling as a way of modulating the post-ischemic neuro-inflammatory process. The immune-brain crosstalk has long been the focus for understanding the mechanisms of sickness behavior, which is an adaptive autonomic, neuroendocrine, and behavioral response to a peripheral inflammation. It is mediated by humoral and neural pathways that mainly involve the circumventricular organs and vagal nerve, respectively. In this review we address the question of how sepsis and stroke can dysregulate this adaptive response, notably by impairing the central integration of peripheral signaling, but also by efferent control of the immune response. We highlight the potential role of gut-brain and brain-spleen signaling in stroke.

Impact of a Postintensive Care Unit Multidisciplinary Follow-up on the Quality of Life (SUIVI-REA): Protocol for a Multicenter Randomized Controlled Trial.

BACKGROUND: Critically ill patients are at risk of developing a postintensive care syndrome (PICS), which is characterized by physical, psychological, and cognitive impairments and which dramatically impacts the patient's quality of life (QoL). No intervention has been shown to improve QoL. We hypothesized that a medical, psychological, and social follow-up would improve QoL by mitigating the PICS. OBJECTIVE: This multicenter, randomized controlled trial (SUIVI-REA) aims to compare a multidisciplinary follow-up with a standard postintensive care unit (ICU) follow-up. METHODS: Patients were randomized to the control or intervention arm. In the intervention arm, multidisciplinary follow-up involved medical, psychological, and social evaluation at ICU discharge and at 3, 6, and 12 months thereafter. In the placebo group, patients were seen only at 12 months by the multidisciplinary team. Baseline characteristics at ICU discharge were collected for all patients. The primary outcome was QoL at 1 year, assessed using the Euro Quality of Life-5 dimensions (EQ5D). Secondary outcomes were mortality, cognitive, psychological, and functional status; social and professional reintegration; and the rate of rehospitalization and outpatient consultations at 1 year. RESULTS: The study was funded by the Ministry of Health in June 2010. It was approved by the Ethics Committee on July 8, 2011. The first and last patient were randomized on December 20, 2012, and September 1, 2017, respectively. A total of 546 patients were enrolled across 11 ICUs. At present, data management is ongoing, and all parties involved in the trial remain blinded. CONCLUSIONS: The SUVI-REA multicenter randomized controlled trial aims to assess whether a post-ICU multidisciplinary follow-up improves QoL at 1 year. TRIAL REGISTRATION: Clinicaltrials.gov NCT01796509; https://clinicaltrials.gov/ct2/show/NCT01796509. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/30496.

Upcoming and urgent challenges in critical care research based on COVID-19 pandemic experience.

While the coronavirus disease 2019 (COVID-19) pandemic placed a heavy burden on healthcare systems worldwide, it also induced urgent mobilisation of research teams to develop treatments preventing or curing the disease and its consequences. It has, therefore, challenged critical care research to rapidly focus on specific fields while forcing critical care physicians to make difficult ethical decisions. This narrative review aims to summarise critical care research -from organisation to research fields- in this pandemic setting and to highlight opportunities to improve research efficiency in the future, based on what is learned from COVID-19. This pressure on research revealed, i.e., (i) the need to harmonise regulatory processes between countries, allowing simplified organisation of international research networks to improve their efficiency in answering large-scale questions; (ii) the importance of developing translational research from which therapeutic innovations can emerge; (iii) the need for improved triage and predictive scores to rationalise admission to the intensive care unit. In this context, key areas for future critical care research and better pandemic preparedness are artificial intelligence applied to healthcare, characterisation of long-term symptoms, and ethical considerations. Such collaborative research efforts should involve groups from both high and low-to-middle income countries to propose worldwide solutions. As a conclusion, stress tests on healthcare organisations should be viewed as opportunities to design new research frameworks and strategies. Worldwide availability of research networks ready to operate is essential to be prepared for next pandemics. Importantly, researchers and physicians should prioritise realistic and ethical goals for both clinical care and research.

Intravenous immunoglobulins in patients with COVID-19-associated moderate-to-severe acute respiratory distress syndrome (ICAR): multicentre, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: Acute respiratory distress syndrome (ARDS) is a major complication of COVID-19 and is associated with high mortality and morbidity. We aimed to assess whether intravenous immunoglobulins (IVIG) could improve outcomes by reducing inflammation-mediated lung injury. METHODS: In this multicentre, double-blind, placebo-controlled trial, done at 43 centres in France, we randomly assigned patients (1:1) receiving invasive mechanical ventilation for up to 72 h with PCR confirmed COVID-19 and associated moderate-to-severe ARDS to receive either IVIG (2 g/kg over 4 days) or placebo. Random assignment was done with a web-based system and was stratified according to the participating centre and the duration of invasive mechanical ventilation before inclusion in the trial (<12 h, 12-24 h, and >24-72 h), and treatment was administered within the first 96 h of invasive mechanical ventilation. To minimise the risk of adverse events, the IVIG administration was divided into four perfusions of 0·5 g/kg each administered over at least 8 hours. Patients in the placebo group received an equivalent volume of sodium chloride 0·9% (10 mL/kg) over the same period. The primary outcome was the number of ventilation-free days by day 28, assessed according to the intention-to-treat principle. This trial was registered on ClinicalTrials.gov, NCT04350580. FINDINGS: Between April 3, and October 20, 2020, 146 patients (43 [29%] women) were eligible for inclusion and randomly assigned: 69 (47%) patients to the IVIG group and 77 (53%) to the placebo group. The intention-to-treat analysis showed no statistical difference in the median number of ventilation-free days at day 28 between the IVIG group (0·0 [IQR 0·0-8·0]) and the placebo group (0·0 [0·0-6·0]; difference estimate 0·0 [0·0-0·0]; p=0·21). Serious adverse events were more frequent in the IVIG group (78 events in 22 [32%] patients) than in the placebo group (47 events in 15 [20%] patients; p=0·089). INTERPRETATION: In patients with COVID-19 who received invasive mechanical ventilation for moderate-to-severe ARDS, IVIG did not improve clinical outcomes at day 28 and tended to be associated with an increased frequency of serious adverse events, although not significant. The effect of IVIGs on earlier disease stages of COVID-19 should be assessed in future trials. FUNDING: Programme Hospitalier de Recherche Clinique.