High-normal versus low-normal mean arterial pressure thresholds in critically ill patients: a systematic review and meta-analysis of randomized trials.

PURPOSE: Targeted blood pressure thresholds remain unclear in critically ill patients. Two prior systematic reviews have not shown differences in mortality with a high mean arterial pressure (MAP) threshold, but there have been new studies published since. Thus, we conducted an updated systematic review and meta-analysis of randomized controlled trials (RCTs) that compared the effect of a high-normal vs low-normal MAP on mortality, favourable neurologic outcome, need for renal replacement therapy, and adverse vasopressor-induced events in critically ill patients. SOURCE: We searched six databases from inception until 1 October 2022 for RCTs of critically ill patients targeted to either a high-normal vs a low-normal MAP threshold for at least 24 hr. We assessed study quality using the revised Cochrane risk-of-bias 2 tool and the risk ratio (RR) was used as the summary measure of association. We used the Grading of Recommendations Assessment, Development, and Evaluation framework to assess the certainty of evidence. PRINCIPAL FINDINGS: We included eight RCTs with 4,561 patients. Four trials were conducted in patients following out-of-hospital cardiac arrest, two in patients with distributive shock requiring vasopressors, one in patients with septic shock, and one in patients with hepatorenal syndrome. The pooled RRs for mortality (eight RCTs; 4,439 patients) and favourable neurologic outcome (four RCTs; 1,065 patients) were 1.06 (95% confidence interval [CI], 0.99 to 1.14; moderate certainty) and 0.99 (95% CI, 0.90 to 1.08; moderate certainty), respectively. The RR for the need for renal replacement therapy (four RCTs; 4,071 patients) was 0.97 (95% CI, 0.87 to 1.08; moderate certainty). There was no statistical between-study heterogeneity across all outcomes. CONCLUSION: This updated systematic review and meta-analysis of RCTs found no differences in mortality, favourable neurologic outcome, or the need for renal replacement therapy between critically ill patients assigned to a high-normal vs low-normal MAP target. STUDY REGISTRATION: PROSPERO (CRD42022307601); registered 28 February 2022.

RéSUMé: OBJECTIF: Les seuils de pression artérielle ciblés demeurent incertains chez les patient·es gravement malades. Deux revues systématiques antérieures n'ont pas montré de différences dans la mortalité avec un seuil élevé de pression artérielle moyenne (PAM), mais de nouvelles études ont été publiées depuis. Pour cette raison, nous avons réalisé une revue systématique mise à jour et une méta-analyse d'études randomisées contrôlées (ERC) comparant l'effet d'une PAM normale élevée vs normale faible sur la mortalité, les devenirs neurologiques favorables, la nécessité d'un traitement substitutif de l'insuffisance rénale et les événements indésirables induits par les vasopresseurs chez les patient·es gravement malades. SOURCES: Nous avons effectué des recherches dans six bases de données depuis leur création jusqu'au 1er octobre 2022 pour trouver des ERC portant sur des patient·es gravement malades chez lesquel·les un seuil de PAM normale élevée ou normale faible a été ciblé pendant au moins 24 heures. Nous avons évalué la qualité des études à l'aide de l'outil de risque de biais 2 révisé de Cochrane, et le risque relatif (RR) a été utilisé comme mesure sommaire de l'association. Nous avons utilisé le système de notation GRADE (Grading of Recommendations Assessment, Development, and Evaluation) pour évaluer la certitude des données probantes. CONSTATATIONS PRINCIPALES: Nous avons inclus huit ERC portant sur 4561 personnes traitées. Quatre études ont été menées chez des patient·es à la suite d'un arrêt cardiaque hors de l'hôpital, deux chez des patient·es présentant un choc distributif nécessitant des vasopresseurs, une chez des patient·es présentant un choc septique et une chez des patient·es atteint·es d'un syndrome hépato-rénal. Les RR combinés pour la mortalité (huit ERC; 4439 personnes) et les devenirs neurologiques favorables (quatre ERC; 1065 personnes) étaient respectivement de 1,06 (intervalle de confiance [IC] à 95 %, 0,99 à 1,14; certitude modérée) et de 0,99 (IC 95 %, 0,90 à 1,08; certitude modérée). Le RR pour le besoin de traitement substitutif de l'insuffisance rénale (quatre ERC; 4071 patient·es) était de 0,97 (IC 95 %, 0,87 à 1,08; certitude modérée). Il n'y avait pas d'hétérogénéité statistique entre les études pour tous les critères d'évaluation. CONCLUSION: Ces revue systématique et méta-analyse mises à jour des ERC n'ont révélé aucune différence dans la mortalité, les devenirs neurologiques favorables ou la nécessité d'un traitement substitutif de l'insuffisance rénale entre les patient·es gravement malades assigné·es à une cible de PAM normale élevée vs normale faible. ENREGISTREMENT DE L'éTUDE: PROSPERO (CRD42022307601); enregistrée le 28 février 2022.

Targeted neurostimulation reverses a spatiotemporal biomarker of treatment-resistant depression.

Major depressive disorder (MDD) is widely hypothesized to result from disordered communication across brain-wide networks. Yet, prior resting-state-functional MRI (rs-fMRI) studies of MDD have studied zero-lag temporal synchrony (functional connectivity) in brain activity absent directional information. We utilize the recent discovery of stereotyped brain-wide directed signaling patterns in humans to investigate the relationship between directed rs-fMRI activity, MDD, and treatment response to FDA-approved neurostimulation paradigm termed Stanford neuromodulation therapy (SNT). We find that SNT over the left dorsolateral prefrontal cortex (DLPFC) induces directed signaling shifts in the left DLPFC and bilateral anterior cingulate cortex (ACC). Directional signaling shifts in the ACC, but not the DLPFC, predict improvement in depression symptoms, and moreover, pretreatment ACC signaling predicts both depression severity and the likelihood of SNT treatment response. Taken together, our findings suggest that ACC-based directed signaling patterns in rs-fMRI are a potential biomarker of MDD.

Control of Line Complications with KiteLock (CLiCK) in the critical care unit: study protocol for a multi-center, cluster-randomized, double-blinded, crossover trial investigating the effect of a novel locking fluid on central line complications in the critical care population.

BACKGROUND: Insertion of a central venous access device (CVAD) allows clinicians to easily access the circulation of a patient to administer life-saving interventions. Due to their invasive nature, CVADs are prone to complications such as bacterial biofilm production and colonization, catheter-related bloodstream infection, occlusion, and catheter-related venous thrombosis. A CVAD is among the most common interventions for patients in the intensive care unit (ICU), exposing this vulnerable population to the risk of nosocomial infection and catheter occlusion. The current standard of care involves the use of normal saline as a catheter locking solution for central venous catheters (CVCs) and peripherally inserted central catheter (PICC) lines, and a citrate lock for hemodialysis catheters. Saline offers little prophylactic measures against catheter complications. Four percent of tetrasodium ethylenediaminetetraacetic acid (EDTA) fluid (marketed as KiteLock Sterile Locking Solution™) is non-antibiotic, possesses antimicrobial, anti-biofilm, and anti-coagulant properties, and is approved by Health Canada as a catheter locking solution. As such, it may be a superior CVAD locking solution than the present standard of care lock in the ICU patient population. METHODS: Our team proposes to fill this knowledge gap by performing a multi-center, cluster-randomized, crossover trial evaluating the impact of 4% tetrasodium EDTA on a primary composite outcome of the incidence rate of central line-associated bloodstream infection (CLABSI), catheter occlusion leading to removal, and use of alteplase to resolve catheter occlusion compared to the standard of care. The study will be performed at five critical care units. DISCUSSION: If successful, the results of this study can serve as evidence for a shift of standard of care practices to include EDTA locking fluid in routine CVAD locking procedures. Completion of this study has the potential to improve CVAD standard of care to become safer for patients, as well as provides an opportunity to decrease strain on healthcare budgets related to treating preventable CVAD complications. Success and subsequent implementation of this intervention in the ICU may also be extrapolated to other patient populations with heavy CVAD use including hemodialysis, oncology, parenteral nutrition, and pediatric patient populations. On a global scale, eradicating biofilm produced by antibiotic-resistant bacteria may serve to lessen the threat of "superbugs" and contribute to international initiatives supporting the termination of antibiotic overuse. TRIAL REGISTRATION: ClinicalTrials.gov NCT04548713, registered on September 9th, 2020.

A comparison of machine learning classifiers for pediatric epilepsy using resting-state functional MRI latency data.

Epilepsy affects 1 in 150 children under the age of 10 and is the most common chronic pediatric neurological condition; poor seizure control can irreversibly disrupt normal brain development. The present study compared the ability of different machine learning algorithms trained with resting-state functional MRI (rfMRI) latency data to detect epilepsy. Preoperative rfMRI and anatomical MRI scans were obtained for 63 patients with epilepsy and 259 healthy controls. The normal distribution of latency z-scores from the epilepsy and healthy control cohorts were analyzed for overlap in 36 seed regions. In these seed regions, overlap between the study cohorts ranged from 0.44-0.58. Machine learning features were extracted from latency z-score maps using principal component analysis. Extreme Gradient Boosting (XGBoost), Support Vector Machines (SVM), and Random Forest algorithms were trained with these features. Area under the receiver operating characteristics curve (AUC), accuracy, sensitivity, specificity and F1-scores were used to evaluate model performance. The XGBoost model outperformed all other models with a test AUC of 0.79, accuracy of 74%, specificity of 73%, and a sensitivity of 77%. The Random Forest model performed comparably to XGBoost across multiple metrics, but it had a test sensitivity of 31%. The SVM model did not perform >70% in any of the test metrics. The XGBoost model had the highest sensitivity and accuracy for the detection of epilepsy. Development of machine learning algorithms trained with rfMRI latency data could provide an adjunctive method for the diagnosis and evaluation of epilepsy with the goal of enabling timely and appropriate care for patients.

Global waves synchronize the brain's functional systems with fluctuating arousal.

We propose and empirically support a parsimonious account of intrinsic, brain-wide spatiotemporal organization arising from traveling waves linked to arousal. We hypothesize that these waves are the predominant physiological process reflected in spontaneous functional magnetic resonance imaging (fMRI) signal fluctuations. The correlation structure ("functional connectivity") of these fluctuations recapitulates the large-scale functional organization of the brain. However, a unifying physiological account of this structure has so far been lacking. Here, using fMRI in humans, we show that ongoing arousal fluctuations are associated with global waves of activity that slowly propagate in parallel throughout the neocortex, thalamus, striatum, and cerebellum. We show that these waves can parsimoniously account for many features of spontaneous fMRI signal fluctuations, including topographically organized functional connectivity. Last, we demonstrate similar, cortex-wide propagation of neural activity measured with electrocorticography in macaques. These findings suggest that traveling waves spatiotemporally pattern brain-wide excitability in relation to arousal.

Use of Corticosteroids in Cardiac Arrest-A Systematic Review and Meta-Analysis.

OBJECTIVES: The objective of this systematic review was to evaluate the impact of intraarrest corticosteroids on neurologic outcomes and mortality in patients with cardiac arrest. DATA SOURCES: We conducted a systematic search using the Cochrane Central Register of Controlled Trials, EMBASE, and MEDLINE databases. STUDY SELECTION: We included all randomized controlled trials and comparative observational studies. We excluded single arm studies, case reports/series, narrative reviews, and studies irrelevant to the focus of this article. DATA EXTRACTION: Two reviewers independently assessed trial eligibility. Data were collected for the following outcomes: primary outcomes included good neurologic outcome, survival to hospital discharge, and survival at greater than or equal to 1 year. Secondary outcomes included incidence of return of spontaneous circulation, ICU and hospital length of stay, duration of vasopressor and inotropic treatment, and blood pressure during cardiopulmonary resuscitation and after return of spontaneous circulation. DATA SYNTHESIS: The pooled estimates from randomized controlled trials for the following subgroups were analyzed using random-effects models: 1) patients with in-hospital cardiac arrest who received vasopressin, steroids, and epinephrine; 2) patients with in-hospital cardiac arrest who used corticosteroids only (i.e., no vasopressin); and 3) patients with out-of-hospital cardiac arrest who used corticosteroids only. Results included an increase in good neurologic outcomes (relative risk, 2.84; 95% CI, 1.36-5.94) and survival to hospital discharge (relative risk, 2.58; 95% CI, 1.36-4.91) in in-hospital cardiac arrest patients receiving vasopressin, steroids, and epinephrine followed by corticosteroids for postresuscitation shock. This was further supported by an increase in return of spontaneous circulation (relative risk, 1.35; 95% CI, 1.12-1.64) and hemodynamics in this population. There was no benefit observed in in-hospital cardiac arrest or out-of-hospital cardiac arrest patients receiving corticosteroids alone. CONCLUSIONS: Our study found that there are limited high-quality data to analyze the association between corticosteroids and reducing mortality in cardiac arrest, but the available data do support future randomized controlled trials. We did find that corticosteroids given as part of a vasopressin, steroids, and epinephrine regimen in in-hospital cardiac arrest patients and for postresuscitation shock did improve neurologic outcomes, survival to hospital discharge, and surrogate outcomes that include return of spontaneous circulation and hemodynamics. We found no benefit in in-hospital cardiac arrest or out-of-hospital cardiac arrest patients receiving corticosteroids only; however, a difference cannot be ruled out due to imprecision and lack of available data.

Convolutional Neural Networks for Pediatric Refractory Epilepsy Classification Using Resting-State Functional Magnetic Resonance Imaging.

OBJECTIVE: This study aims to evaluate the performance of convolutional neural networks (CNNs) trained with resting-state functional magnetic resonance imaging (rfMRI) latency data in the classification of patients with pediatric epilepsy from healthy controls. METHODS: Preoperative rfMRI and anatomic magnetic resonance imaging scans were obtained from 63 pediatric patients with refractory epilepsy and 259 pediatric healthy controls. Latency maps of the temporal difference between rfMRI and the global mean signal were calculated using voxel-wise cross-covariance. Healthy control and epilepsy latency z score maps were pseudorandomized and partitioned into training data (60%), validation data (20%), and test data (20%). Healthy control individuals and patients with epilepsy were labeled as negative and positive, respectively. CNN models were then trained with the designated training data. Model hyperparameters were evaluated with a grid-search method. The model with the highest sensitivity was evaluated using unseen test data. Accuracy, sensitivity, specificity, F1 score, and area under the receiver operating characteristic curve were used to evaluate the ability of the model to classify epilepsy in the test data set. RESULTS: The model with the highest validation sensitivity correctly classified 74% of unseen test patients with 85% sensitivity, 71% specificity, F1 score of 0.56, and an area under the receiver operating characteristic curve of 0.86. CONCLUSIONS: Using rfMRI latency data, we trained a CNN model to classify patients with pediatric epilepsy from healthy controls with good performance. CNN could serve as an adjunct in the diagnosis of pediatric epilepsy. Identification of pediatric epilepsy earlier in the disease course could decrease time to referral to specialized epilepsy centers and thus improve prognosis in this population.

Prone Position after Liberation from Prolonged Mechanical Ventilation in COVID-19 Respiratory Failure.

DESIGN: This is a retrospective case series describing the feasibility and tolerability of postextubation prone positioning (PEPP) and its impact on physiologic parameters in a tertiary intensive care unit during the COVID-19 pandemic. Setting and Patients. This study was conducted on patients with COVID-19 respiratory failure hospitalized in a tertiary Intensive Care Unit at Surrey Memorial Hospital during the COVID-19 pandemic. Measurements and Results. We did not find prior reports of PEPP following prolonged intubation in the literature. Four patients underwent a total of 13 PEPP sessions following liberation from prolonged mechanical ventilation. Each patient underwent a median of 3 prone sessions (IQR: 2, 4.25) lasting a median of 1.5 hours (IQR: 1.2, 2.1). PEPP sessions were associated with a reduction in median oxygen requirements, patient respiratory rate, and reintubation rate. The sessions were well tolerated by patients, nursing, and the allied health team. CONCLUSIONS: The novel practice of PEPP after liberation from prolonged mechanical ventilation in patients with COVID-19 respiratory failure is feasible and well tolerated, and may be associated with favourable clinical outcomes including improvement in oxygenation and respiratory rate and a low rate of reintubation. Larger prospective studies of PEPP are warranted.

Caractéristiques de départ et issues chez des patients atteints de COVID-19 hospitalisés dans des unités de soins intensifs à Vancouver (Canada) : série de cas.

CONTEXTE: La pandémie de maladie à coronavirus du syndrome respiratoire aigu sévère 2 (SRAS-CoV-2) est associée à une mortalité élevée dans les unités de soins intensifs (USI). Nous avons voulu décrire les caractéristiques cliniques et les issues des patients gravement atteints de la maladie à coronavirus 2019 (COVID-19) en contexte canadien. MÉTHODES: Nous avons procédé à l'étude rétrospective d'une série de cas graves d'infection au SRAS-CoV-2 confirmée en laboratoire hospitalisés dans l'une des 6 USI du Vancouver métropolitain, en Colombie-Britannique (Canada), entre le 21 février et le 14 avril 2020. Les données démographiques, les renseignements sur la prise en charge et les résultats ont été recueillis à partir des dossiers médicaux, électroniques ou non, des patients. RÉSULTATS: Entre le 21 février et le 14 avril 2020, 117 patients ont été admis dans une USI avec un diagnostic confirmé de COVID-19. L'âge médian était de 69 ans (écart interquartile [EI] 60­75 ans); et 38 (32,5 %) étaient des femmes. Au moins une comorbidité était présente chez 86 patients (73,5 %). La ventilation mécanique a été nécessaire chez 74 patients (63,2 %). La durée de la ventilation mécanique a été de 13,5 jours (EI 8­22 jours) dans l'ensemble et de 11 jours (II 6­16) chez les patients qui ont reçu leur congé de l'USI. Du tocilizumab a été administré à 4 patients et de l'hydroxychloroquine à 1 patient. En date du 5 mai 2020, 18 patients (15,4 %) étaient décédés, 12 (10,3 %) étaient toujours à l'USI, 16 (13,7 %) avaient obtenu leur congé de l'USI, mais restaient hospitalisés, et 71 (60,7 %) avaient pu retourner à la maison. INTERPRÉTATION: Dans cette étude, la mortalité chez les patients gravement malades de la COVID-19 hospitalisés dans une USI a été moins élevée que chez les patients d'études précédentes. Ces résultats donnent à penser que le pronostic des cas graves de COVID-19 pourrait ne pas être aussi sombre que ce qui avait d'abord été rapporté.

Quantification of Neurological Blood-Based Biomarkers in Critically Ill Patients With Coronavirus Disease 2019.

OBJECTIVES: To provide an objective characterization of acute neurologic injury in critically ill patients with coronavirus disease 2019. DESIGN: Prospective observational study. Demographics, comorbidities, and daily clinical physiologic and laboratory data were collected. Plasma levels of neurofilament-light chain, total tau, ubiquitin carboxy-terminal hydrolase L1, and glial fibrillary acidic protein were measured. The primary neurologic outcome was delirium defined by the Intensive Care Delirium Screening Checklist (scale 1-8). Associations among plasma biomarkers, respiratory failure, and inflammation were analyzed. SETTING: Multicenter study in ICUs. PATIENTS: Critically ill patients with respiratory failure, with coronavirus disease 2019, or without (ICU control). MEASUREMENTS AND MAIN RESULTS: A total of 27 patients with coronavirus disease 2019 and 19 ICU controls were enrolled. Compared with ICU controls with pneumonia of other etiology, patients with coronavirus disease 2019 had significantly higher glial fibrillary acidic protein (272 pg/mL [150-555 pg/mL] vs 118 pg/mL [78.5-168 pg/mL]; p = 0.0009). In coronavirus disease 2019 patients, glial fibrillary acidic protein (rho = 0.5115, p = 0.0064), ubiquitin carboxy-terminal hydrolase L1 (rho = 0.4056, p = 0.0358), and neurofilament-light chain (rho = 0.6223, p = 0.0005) positively correlated with Intensive Care Delirium Screening Checklist score and were increased in patients with delirium (Intensive Care Delirium Screening Checklist ≥ 4) in the coronavirus disease 2019 group but not in ICU controls. There were no associations between the measures of respiratory function or cytokines with glial fibrillary acidic protein, total tau, ubiquitin carboxy-terminal hydrolase L1, or neurofilament-light chain levels in patients with coronavirus disease 2019. CONCLUSIONS: Plasma glial fibrillary acidic protein is two-fold higher in critically ill patients with coronavirus disease 2019 compared with ICU controls. Higher levels of glial fibrillary acidic protein, ubiquitin carboxy-terminal hydrolase L1, and neurofilament-light chain associate with delirium in patients with coronavirus disease 2019. Elevated plasma glial fibrillary acidic protein, ubiquitin carboxy-terminal hydrolase L1, and neurofilament-light chain are independent of respiratory function and peripheral cytokines.

The Association of Inflammatory Cytokines in the Pulmonary Pathophysiology of Respiratory Failure in Critically Ill Patients With Coronavirus Disease 2019.

OBJECTIVES: The majority of coronavirus disease 2019 mortality and morbidity is attributable to respiratory failure from severe acute respiratory syndrome coronavirus 2 infection. The pathogenesis underpinning coronavirus disease 2019-induced respiratory failure may be attributable to a dysregulated host immune response. Our objective was to investigate the pathophysiological relationship between proinflammatory cytokines and respiratory failure in severe coronavirus disease 2019. DESIGN: Multicenter prospective observational study. SETTING: ICU. PATIENTS: Critically ill patients with coronavirus disease 2019 and noncoronavirus disease 2019 critically ill patients with respiratory failure (ICU control group). INTERVENTIONS: Daily measurement of serum inflammatory cytokines. MEASUREMENTS AND MAIN RESULTS: Demographics, comorbidities, clinical, physiologic, and laboratory data were collected daily. Daily serum samples were drawn for measurements of interleukin-1ß, interleukin-6, interleukin-10, and tumor necrosis factor-α. Pulmonary outcomes were the ratio of Pao2/Fio2 and static lung compliance. Twenty-six patients with coronavirus disease 2019 and 22 ICU controls were enrolled. Of the patients with coronavirus disease 2019, 58% developed acute respiratory distress syndrome, 62% required mechanical ventilation, 12% underwent extracorporeal membrane oxygenation, and 23% died. A negative correlation between interleukin-6 and Pao2/Fio2 (rho, -0.531; p = 0.0052) and static lung compliance (rho, -0.579; p = 0.033) was found selectively in the coronavirus disease 2019 group. Diagnosis of acute respiratory distress syndrome was associated with significantly elevated serum interleukin-6 and interleukin-1ß on the day of diagnosis. CONCLUSIONS: The inverse relationship between serum interleukin-6 and Pao2/Fio2 and static lung compliance is specific to severe acute respiratory syndrome coronavirus 2 infection in critically ill patients with respiratory failure. Similar observations were not found with interleukin-ß or tumor necrosis factor-α.

The association of ABO blood group with indices of disease severity and multiorgan dysfunction in COVID-19.

Studies on severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) suggest a protective effect of anti-A antibodies against viral cell entry that may hold relevance for SARS-CoV-2 infection. Therefore, we aimed to determine whether ABO blood groups are associated with different severities of COVID-19. We conducted a multicenter retrospective analysis and nested prospective observational substudy of critically ill patients with COVID-19. We collected data pertaining to age, sex, comorbidities, dates of symptom onset, hospital admission, intensive care unit (ICU) admission, mechanical ventilation, continuous renal replacement therapy (CRRT), standard laboratory parameters, and serum inflammatory cytokines. National (N = 398 671; P = .38) and provincial (n = 62 246; P = .60) ABO blood group distributions did not differ from our cohort (n = 95). A higher proportion of COVID-19 patients with blood group A or AB required mechanical ventilation (P = .02) and CRRT (P = .004) and had a longer ICU stay (P = .03) compared with patients with blood group O or B. Blood group A or AB also had an increased probability of requiring mechanical ventilation and CRRT after adjusting for age, sex, and presence of ≥1 comorbidity. Inflammatory cytokines did not differ between patients with blood group A or AB (n = 11) vs O or B (n = 14; P > .10 for all cytokines). Collectively, our data indicate that critically ill COVID-19 patients with blood group A or AB are at increased risk for requiring mechanical ventilation, CRRT, and prolonged ICU admission compared with patients with blood group O or B. Further work is needed to understand the underlying mechanisms.

Probabilistic flow in brain-wide activity.

Patterns of low frequency brain-wide activity have drawn attention across multiple disciplines in neuroscience. Brain-wide activity patterns are often described through correlations, which capture concurrent increases and decreases in neural activity. More recently, several groups have described reproducible temporal sequences across the brain, illustrating precise long-distance control over the timing of low frequency activity. Features of correlation and temporal organization both point to a systems-level structure of brain activity consisting of large-scale networks and their mutual interactions. Yet a unified view for understanding large networks and their interactions remains elusive. Here, we propose a framework for computing probabilistic flow in brain-wide activity. We demonstrate how flow probabilities are modulated across rest and task states and show that the probabilistic perspective captures both intra- and inter-network dynamics. Finally, we suggest that a probabilistic framework may prove fruitful in characterizing low frequency brain-wide activity in health and disease.

How the high acuity unit changes mortality in the intensive care unit: a retrospective before-and-after study.

PURPOSE: High acuity units (HAU) are hospital units that provide patients with more acute care and closer monitoring than a general hospital ward but are not as resource intensive as an intensive care unit (ICU). Nevertheless, the impact of opening a HAU on ICU patient outcomes remains poorly defined. We investigated how the creation of a HAU impacted patient outcomes in the ICU. METHODS: This historical cohort study compared ICU patient in-hospital mortality, ICU length of stay (LOS), and hospital LOS before and after the creation of a HAU in a tertiary-care hospital with a medical/surgical ICU between 1 January 2013 and 31 December 2017. RESULTS: Data from 4,380 patients (984 in the pre-HAU group and 3,396 in the post-HAU group) were analyzed. In this cohort of ICU patients, 360 (37%) died in the pre-HAU group before the creation of a HAU, and 1,074 (32%) died in the post-HAU group after the creation of a HAU. The creation of a HAU was associated with lower relative risk of in-hospital mortality (adjusted risk ratio, 0.80; 95% confidence interval [CI], 0.72 to 0.89; P < 0.001). The creation of a HAU was also associated with reduced ICU and hospital LOS with a 12% increase in the rate of ICU discharge (adjusted sub-distribution hazard ratio [SHR], 1.12; 95% CI, 1.02 to 1.23; P = 0.02) and a 26% increase in the rate of hospital discharge (adjusted SHR, 1.26; 95% CI, 1.14 to 1.39; P < 0.001), when accounting for the competing risk of death. CONCLUSIONS: These data support the hypothesis that the creation of a HAU may be associated with reduced in-hospital mortality, ICU LOS, and hospital LOS for ICU patients.

RéSUMé: OBJECTIF: Les unités de soins intermédiaires sont des départements hospitaliers qui prodiguent des soins plus aigus et un monitorage plus serré aux patients qu'une unité générale, mais qui ne nécessitent pas autant de ressources qu'une unité de soins intensifs (USI). L'impact de l'ouverture d'une unité de soins intermédiaires sur les devenirs des patients à l'USI n'a pourtant été que peu décrit. Nous avons exploré la façon dont la création d'une unité de soins intermédiaires a eu un impact sur les devenirs des patients à l'USI. MéTHODE: Cette étude de cohorte historique a comparé la mortalité hospitalière, la durée de séjour à l'USI et la durée de séjour hospitalier des patients à l'USI avant et après la création d'une unité de soins intermédiaires dans un hôpital de soins tertiaires disposant d'une USI médicale/chirurgicale entre le 1er janvier 2013 et le 31 décembre 2017. RéSULTATS: Les données de 4380 patients (984 dans le groupe pré unité de soins intermédiaires et 3396 dans le groupe post unité de soins intermédiaires) ont été analysées. Dans cette cohorte de patients de l'USI, 360 (37 %) sont décédés avant la création de l'unité de soins intermédiaires, et 1074 (32 %) sont décédés après. La création d'une unité de soins intermédiaires a été associée à un risque relatif plus faible de mortalité hospitalière (risque relatif ajusté, 0,80; intervalle de confiance [IC] 95 %, 0,72 à 0,89; P < 0,001). La création d'une unité de soins intermédiaires a également été associée à une durée de séjour réduite à l'USI et à l'hôpital, avec une augmentation de 12 % du taux de congé de l'USI (rapport de risque ajusté [RRA], 1,12; IC 95 %, 1,02 à 1,23; P = 0,02) et une augmentation de 26 % du taux de congé de l'hôpital (RRA, 1,26; IC 95 %, 1,14 à 1,39; P < 0,001), en tenant compte du risque concurrent de décès. CONCLUSION: Ces données appuient l'hypothèse que la création d'une unité de soins intermédiaires pourrait être associée à une réduction de la mortalité hospitalière, de la durée de séjour à l'USI et de la durée de séjour à l'hôpital pour les patients de l'USI.

Plasticity and Spontaneous Activity Pulses in Disused Human Brain Circuits.

To induce brain plasticity in humans, we casted the dominant upper extremity for 2 weeks and tracked changes in functional connectivity using daily 30-min scans of resting-state functional MRI (rs-fMRI). Casting caused cortical and cerebellar regions controlling the disused extremity to functionally disconnect from the rest of the somatomotor system, while internal connectivity within the disused sub-circuit was maintained. Functional disconnection was evident within 48 h, progressed throughout the cast period, and reversed after cast removal. During the cast period, large, spontaneous pulses of activity propagated through the disused somatomotor sub-circuit. The adult brain seems to rely on regular use to maintain its functional architecture. Disuse-driven spontaneous activity pulses may help preserve functionally disconnected sub-circuits.

Association between intensive care unit occupancy at discharge, afterhours discharges, and clinical outcomes: a historical cohort study.

PURPOSE: There is a paucity of evidence evaluating whether intensive care unit (ICU) discharge occupancy is associated with clinical outcomes. It is unknown whether increased discharge occupancy leads to greater afterhours discharges and downstream consequences. We explore the association between ICU discharge occupancy and afterhours discharges, 72-hr readmission, and 30-day mortality. METHODS: This single-centre, historical cohort study included all patients discharged from the Vancouver General Hospital ICU between 5 April 2010 and 13 September 2017. Data were obtained from the British Columbia Critical Care Database. Occupancy was defined as the number of ICU bed hours utilized divided by the available bed hours for that day. Any discharge between 22:00 and 6:59 was considered afterhours. Logistic regression models adjusting for important covariates were constructed. RESULTS: We included 8,862 ICU discharges representing 7,288 individual patients. There were 1,180 (13.3%) afterhours discharges, 408 (4.6%) 72-hr readmissions, and 574 (6.5%) 30-day post-discharge deaths. Greater discharge occupancy was associated with afterhours discharges (per 10% increase: adjusted odds ratio [aOR], 1.12; 95% confidence interval [CI], 1.03 to 1.20; P = 0.005). Discharge occupancy was not associated with 72-hr readmission (per 10% increase: aOR, 0.97; 95% CI, 0.87 to 1.09; P = 0.62) or 30-day mortality (per 10% increase: aOR, 1.05; 95% CI, 0.95 to 1.16; P = 0.32). Afterhours discharge was not associated with 72-hr readmission (aOR, 1.15; 95% CI, 0.86 to 1.54; P = 0.34) or 30-day mortality (aOR, 1.05; 95% CI, 0.82 to 1.36; P = 0.69). CONCLUSIONS: Greater ICU discharge occupancy was associated with a significant increase in afterhours discharges. Nevertheless, neither discharge occupancy nor afterhours discharge were associated with 72-hr readmission or 30-day mortality.

RéSUMé: OBJECTIF: Il n'existe que peu de données probantes évaluant si le taux d'occupation de l'unité de soins intensifs (USI) au moment du congé est associé aux devenirs cliniques. Nous ne savons pas si un taux d'occupation plus élevé au moment du congé entraîne davantage de congés pendant la nuit et si cette situation a des conséquences. Nous avons exploré l'association entre le taux d'occupation de l'USI au moment du congé et les congés donnés pendant la nuit, la réadmission dans les premières 72 h, et la mortalité à 30 jours. MéTHODE: Cette étude de cohorte historique et monocentrique a englobé tous les patients ayant reçu leur congé de l'USI de l'Hôpital général de Vancouver entre le 5 avril 2010 et le 13 septembre 2017. Les données ont été tirées de la Base de données des soins intensifs de Colombie-Britannique (British Columbia Critical Care Database). Le taux d'occupation était défini comme le nombre d'heures d'occupation de lit de l'USI utilisées divisé par le nombre d'heures d'occupation de lit disponibles pour ladite journée. Tout congé reçu entre 22 h et 6 h 59 était considéré comme survenant pendant la nuit. Des modèles de régression logistique ont été élaborés afin de tenir compte des covariables importantes. RéSULTATS: Nous avons inclus 8862 congés de l'USI, représentant 7288 patients individuels. Au total, il y a eu 1180 (13,3 %) congés donnés pendant la nuit, 408 (4,6 %) réadmissions dans les 72 h suivantes, et 574 (6,5 %) décès à 30 jours après le congé. Un taux d'occupation plus élevé au moment du congé était associé à des congés pendant la nuit (par augmentation de 10 % : rapport de cotes ajusté [RCA], 1,12; intervalle de confiance [IC] 95 %, 1,03 à 1,20; P = 0,005). Le taux d'occupation lors du congé n'a pas été associé à une réadmission dans les premières 72 h (par augmentation de 10 % : RCA, 0,97; IC 95 %, 0,87 à 1,09; P = 0,62) ou à une mortalité à 30 jours (par augmentation de 10 % : RCA, 1,05; IC 95 %, 0,95 à 1,16; P = 0,32). Les congés pendant la nuit n'ont pas été associés à une réadmission dans les 72 h suivantes (RCA, 1,15; IC 95 %, 0,86 à 1,54; P = 0,34) ou à une mortalité à 30 jours (RCA, 1,05; IC 95 %, 0,82 à 1,36; P = 0,69). CONCLUSION: Un taux d'occupation de l'USI plus élevé au moment du congé était associé à une augmentation significative des congés donnés pendant la nuit. Cependant, ni le taux d'occupation lors du congé, ni le congé donné pendant la nuit, n'étaient associés à une réadmission à 72 h ou une mortalité à 30 jours.