Multimodal Prediction of 3- and 12-Month Outcomes in ICU Patients with Acute Disorders of Consciousness

BACKGROUND

In intensive care unit (ICU) patients with coma and other disorders of consciousness (DoC), outcome prediction is key to decision-making regarding prognostication, neurorehabilitation, and management of family expectations. Current prediction algorithms are largely based on chronic DoC, whereas multimodal data from acute DoC are scarce. Therefore, the Consciousness in Neurocritical Care Cohort Study Using Electroencephalography and Functional Magnetic Resonance Imaging (i.e. CONNECT-ME; ClinicalTrials.gov identifier: NCT02644265) investigates ICU patients with acute DoC due to traumatic and nontraumatic brain injuries, using electroencephalography (EEG) (resting-state and passive paradigms), functional magnetic resonance imaging (fMRI) (resting-state) and systematic clinical examinations.

METHODS

We previously presented results for a subset of patients (n = 87) concerning prediction of consciousness levels in the ICU. Now we report 3- and 12-month outcomes in an extended cohort (n = 123). Favorable outcome was defined as a modified Rankin Scale score ≤ 3, a cerebral performance category score ≤ 2, and a Glasgow Outcome Scale Extended score ≥ 4. EEG features included visual grading, automated spectral categorization, and support vector machine consciousness classifier. fMRI features included functional connectivity measures from six resting-state networks. Random forest and support vector machine were applied to EEG and fMRI features to predict outcomes. Here, random forest results are presented as areas under the curve (AUC) of receiver operating characteristic curves or accuracy. Cox proportional regression with in-hospital death as a competing risk was used to assess independent clinical predictors of time to favorable outcome.

RESULTS

Between April 2016 and July 2021, we enrolled 123 patients (mean age 51 years, 42% women). Of 82 (66%) ICU survivors, 3- and 12-month outcomes were available for 79 (96%) and 77 (94%), respectively. EEG features predicted both 3-month (AUC 0.79 [95% confidence interval (CI) 0.77-0.82]) and 12-month (AUC 0.74 [95% CI 0.71-0.77]) outcomes. fMRI features appeared to predict 3-month outcome (accuracy 0.69-0.78) both alone and when combined with some EEG features (accuracies 0.73-0.84) but not 12-month outcome (larger sample sizes needed). Independent clinical predictors of time to favorable outcome were younger age (hazard ratio [HR] 1.04 [95% CI 1.02-1.06]), traumatic brain injury (HR 1.94 [95% CI 1.04-3.61]), command-following abilities at admission (HR 2.70 [95% CI 1.40-5.23]), initial brain imaging without severe pathological findings (HR 2.42 [95% CI 1.12-5.22]), improving consciousness in the ICU (HR 5.76 [95% CI 2.41-15.51]), and favorable visual-graded EEG (HR 2.47 [95% CI 1.46-4.19]).

CONCLUSIONS

Our results indicate that EEG and fMRI features and readily available clinical data predict short-term outcome of patients with acute DoC and that EEG also predicts 12-month outcome after ICU discharge.

Multimodal prediction of residual consciousness in the intensive care unit: the CONNECT-ME study

Functional MRI (fMRI) and EEG may reveal residual consciousness in patients with disorders of consciousness (DoC), as reflected by a rapidly expanding literature on chronic DoC. However, acute DoC is rarely investigated, although identifying residual consciousness is key to clinical decision-making in the intensive care unit (ICU). Therefore, the objective of the prospective, observational, tertiary centre cohort, diagnostic phase IIb study 'Consciousness in neurocritical care cohort study using EEG and fMRI' (CONNECT-ME, NCT02644265) was to assess the accuracy of fMRI and EEG to identify residual consciousness in acute DoC in the ICU. Between April 2016 and November 2020, 87 acute DoC patients with traumatic or non-traumatic brain injury were examined with repeated clinical assessments, fMRI and EEG. Resting-state EEG and EEG with external stimulations were evaluated by visual analysis, spectral band analysis and a Support Vector Machine (SVM) consciousness classifier. In addition, within- and between-network resting-state connectivity for canonical resting-state fMRI networks was assessed. Next, we used EEG and fMRI data at study enrolment in two different machine-learning algorithms (Random Forest and SVM with a linear kernel) to distinguish patients in a minimally conscious state or better (≥MCS) from those in coma or unresponsive wakefulness state (≤UWS) at time of study enrolment and at ICU discharge (or before death). Prediction performances were assessed with area under the curve (AUC). Of 87 DoC patients (mean age, 50.0 ± 18 years, 43% female), 51 (59%) were ≤UWS and 36 (41%) were ≥ MCS at study enrolment. Thirty-one (36%) patients died in the ICU, including 28 who had life-sustaining therapy withdrawn. EEG and fMRI predicted consciousness levels at study enrolment and ICU discharge, with maximum AUCs of 0.79 (95% CI 0.77-0.80) and 0.71 (95% CI 0.77-0.80), respectively. Models based on combined EEG and fMRI features predicted consciousness levels at study enrolment and ICU discharge with maximum AUCs of 0.78 (95% CI 0.71-0.86) and 0.83 (95% CI 0.75-0.89), respectively, with improved positive predictive value and sensitivity. Overall, both machine-learning algorithms (SVM and Random Forest) performed equally well. In conclusion, we suggest that acute DoC prediction models in the ICU be based on a combination of fMRI and EEG features, regardless of the machine-learning algorithm used.

Endovascular treatment for cerebral venous sinus thrombosis - a single center study

BACKGROUND

Cerebral venous sinus thrombosis (CVST) is a rare cerebrovascular disorder. The majority of these patients respond favorably to systemic anticoagulation. However, a subset of patients will deteriorate clinically, despite optimal medical therapy.

METHODS

Retrospective single center study of 28 consecutive CVST patients treated with systemic anticoagulation and additional endovascular therapy.

RESULTS

Median age was 37.5 years (range 15-76 years), there were 21 (75%) women, and 20 (71%) had thrombosis involving ≥2 venous sinuses. Intracranial hemorrhage (ICH) was present at admission in 18 patients (64%). Endovascular therapy consisted of local thrombolysis in 26 (93%) patients; 9 patients (32%) had additional mechanical thrombectomy, and in 2 (7%) patients thrombectomy alone was performed. Complete recanalization at end of the final intervention was achieved in 15 patients (54%), partial recanalization in 11 patients (39%), whereas there was no recanalization in 2 patients (7%). On follow-up imaging, conducted between 3 and 6 months, recanalization further improved to 76%, 19% and 5%, respectively. A favorable outcome (mRS ≤ 2) was achieved in 63% of patients at 3 months, which improved to 79% at 6 months. Post-procedural ICH or volume expansion of preexisting ICH was seen in 9 patients (32%). In total 5 patients died (18%).

CONCLUSIONS

Systemic anticoagulation with the addition of endovascular therapy with local thrombolysis and/or mechanical thrombectomy is a potential strategy to obtain recanalization in patients with CVST who deteriorate clinically despite medical therapy or are comatose. Endovascular therapy may increase the risk of ICH.

Disseminated intravascular coagulation or acute coagulopathy of trauma shock early after trauma? An observational study

Introduction

It is debated whether early trauma-induced coagulopathy (TIC) in severely injured patients reflects disseminated intravascular coagulation (DIC) with a fibrinolytic phenotype, acute coagulopathy of trauma shock (ACoTS) or yet other entities. This study investigated the prevalence of overt DIC and ACoTS in trauma patients and characterized these conditions based on their biomarker profiles.

Methods

An observational study was carried out at a single Level I Trauma Center. Eighty adult trauma patients (≥18 years) who met criteria for full trauma team activation and had an arterial cannula inserted were included. Blood was sampled a median of 68 minutes (IQR 48 to 88) post-injury. Data on demography, biochemistry, injury severity score (ISS) and mortality were recorded. Plasma/serum was analyzed for biomarkers reflecting tissue/endothelial cell/glycocalyx damage (histone-complexed DNA fragments, Annexin V, thrombomodulin, syndecan-1), coagulation activation/inhibition (prothrombinfragment 1+2, thrombin/antithrombin-complexes, antithrombin, protein C, activated protein C, endothelial protein C receptor, protein S, tissue factor pathway inhibitor, vWF), factor consumption (fibrinogen, FXIII), fibrinolysis (D-dimer, tissue-type plasminogen activator, plasminogen activator inhibitor-1) and inflammation (interleukin (IL)-6, terminal complement complex (sC5b-9)). Comparison of patients stratified according to the presence or absence of overt DIC (International Society of Thrombosis and Hemostasis (ISTH) criteria) or ACoTS (activated partial thromboplastin time (APTT) and/or international normalized ratio (INR) above normal reference).

Results

No patients had overt DIC whereas 15% had ACoTS. ACoTS patients had higher ISS, transfusion requirements and mortality (all P < 0.01) and a biomarker profile suggestive of enhanced tissue, endothelial cell and glycocalyx damage and consumption coagulopathy with low protein C, antithrombin, fibrinogen and FXIII levels, hyperfibrinolysis and inflammation (all P < 0.05). Importantly, in non-ACoTS patients, apart from APTT/INR, higher ISS correlated with biomarkers of enhanced tissue, endothelial cell and glycocalyx damage, protein C activation, coagulation factor consumption, hyperfibrinolysis and inflammation, that is, resembling that observed in patients with ACoTS.

Conclusions

ACoTS and non-ACoTS may represent a continuum of coagulopathy reflecting a progressive early evolutionarily adapted hemostatic response to the trauma hit and both are parts of TIC whereas DIC does not appear to be part of this early response.

Effect of alveolar hypoxia on segmental pulmonary vascular resistance and lung fluid balance in dogs

In a biventricular bypass preparation with constant-flow perfusion, pulmonary arterial pressure (Ppa), average pulmonary capillary pressure (Ppc), venous pressure (Pv), extravascular lung water volume (EVWd) and capillary permeability-surface area product for urea (PS) were determined in control animals and in animals subjected to alveolar hypoxia. During hypoxia, Ppa increased in a biphasic manner, the site of hypoxic pulmonary vasoconstriction being located in the arterial upstream segment. At baseline, Ppc values were identical in control and experimental animals (3.4 +/- 0.4 vs. 3.6 +/- 0.2 mmHg). During 150 min of airway hypoxia, the rise in Ppc (5.1 +/- 0.3 mmHg) did not exceed the rise in Ppc (4.9 +/- 0.5 mmHg) recorded in control animals at same time interval during normoxic ventilation. EVWd increased during hypoxia to values significantly higher than those obtained in control animals (0.559 +/- 0.036 vs. 0.466 +/- 0.027 mL water g-1 lung). PS remained unchanged at baseline level throughout experiments in both groups of animals. Present data suggest that lung oedema formation during alveolar hypoxia may be caused by increased transcapillary fluid loss preferentially through transcellular hydraulic pathways in capillary endothelial cells.

[Acute respiratory distress syndrome. Pathogenesis and therapy of acute pulmonary failure]

Adult respiratory distress syndrome (ARDS) is the pulmonary response to systemic inflammation precipitated by local or systemic tissue hypoxia, or ischaemia and reperfusion. ARDS is a dynamic, pathological process with a multifactorial etiology. The main clinical manifestations of ARDS are dyspnoea, non-cardiogenic pulmonary oedema, and hypoxia due to increased pulmonary capillary permeability, pulmonary vasoconstriction and diminished pulmonary vascular reactivity. Eventually this pulmonary pathology results in first, oedema, pulmonary hypertension, and increased ventilation-perfusion inequality and later, pulmonary remodelling and irreversible pulmonary hypertension. The inflammatory mechanisms involved in acute lung injury are complex and include activation of polymorphonuclear neutrophils, endothelial cells, and synthesis of free radicals, predominantly derived from oxygen. Cytokines synthesized by macrophages maintain and regulate the inflammatory host response. Immune-modulating therapy in ARDS is yet experimental. Accordingly, treatment in ARDS is supportive, directed towards pulmonary oedema, pulmonary hypertension and hypoxaemia. The use of low tidal volumes and low inspiratory pressures in mechanical ventilation is established therapy. The goal in haemodynamic monitoring by applying a Swan-Ganz catheter is to obtain a low pulmonary capillary wedge pressure (< 12-15 mmHg) without compromising adequate delivery of oxygen to vital organs. For treatment of pulmonary hypertension nitric oxide is useful. Change of position and inhalation with beta2-agonists are therapeutic possibilities. Steroids may be of benefit in the late proliferative phase of ARDS.

Effect of prolonged alveolar hypoxia on pulmonary arterial pressure and segmental vascular resistance

The time course of hypoxic pulmonary vasoconstriction and its segmental distribution were studied during prolonged (150 min) alveolar hypoxia in in vivo dog lungs at constant-flow perfusion. With the pulmonary and the systemic circulations separated by two extracorporeal circuits, adequate systemic oxygenation was achieved throughout the experiments. The pulmonary circulation exhibited a time-related biphasic hypoxic vasoconstrictor response: an initial rapid contraction [79 +/- 11% (SE) above control level] was followed by a partial relaxation when a second slow and sustained vasoconstriction (92 +/- 13% above control level) superseded. We partitioned the pulmonary circulation into two segments by arterial occlusion: an upstream arterial segment and a downstream segment consisting of a middle and a venous segment. Measurements were performed at baseline and during the late sustained vasoconstrictor response. Prolonged alveolar hypoxia increased pulmonary capillary pressure by 90 +/- 18%, the site of pulmonary vasomotion being the arterial upstream and downstream middle and venous segments.