Intracranial pressure monitoring in adult patients with traumatic brain injury: challenges and innovations.

Intracranial pressure monitoring enables the detection and treatment of intracranial hypertension, a potentially lethal insult after traumatic brain injury. Despite its widespread use, robust evidence supporting intracranial pressure monitoring and treatment remains sparse. International studies have shown large variations between centres regarding the indications for intracranial pressure monitoring and treatment of intracranial hypertension. Experts have reviewed these two aspects and, by consensus, provided practical approaches for monitoring and treatment. Advances have occurred in methods for non-invasive estimation of intracranial pressure although, for now, a reliable way to non-invasively and continuously measure intracranial pressure remains aspirational. Analysis of the intracranial pressure signal can provide information on brain compliance (ie, the ability of the cranium to tolerate volume changes) and on cerebral autoregulation (ie, the ability of cerebral blood vessels to react to changes in blood pressure). The information derived from the intracranial pressure signal might allow for more individualised patient management. Machine learning and artificial intelligence approaches are being increasingly applied to intracranial pressure monitoring, but many obstacles need to be overcome before their use in clinical practice could be attempted. Robust clinical trials are needed to support indications for intracranial pressure monitoring and treatment. Progress in non-invasive assessment of intracranial pressure and in signal analysis (for targeted treatment) will also be crucial.

MesenchymAl stromal cells for Traumatic bRain Injury (MATRIx): a study protocol for a multicenter, double-blind, randomised, placebo-controlled phase II trial.

BACKGROUND: Traumatic brain injury (TBI) is a significant cause of death and disability, with no effective neuroprotective drugs currently available for its treatment. Mesenchymal stromal cell (MSC)-based therapy shows promise as MSCs release various soluble factors that can enhance the injury microenvironment through processes, such as immunomodulation, neuroprotection, and brain repair. Preclinical studies across different TBI models and severities have demonstrated that MSCs can improve functional and structural outcomes. Moreover, clinical evidence supports the safety of third-party donor bank-stored MSCs in adult subjects. Building on this preclinical and clinical data, we present the protocol for an academic, investigator-initiated, multicenter, double-blind, randomised, placebo-controlled, adaptive phase II dose-finding study aiming to evaluate the safety and efficacy of intravenous administration of allogeneic bone marrow-derived MSCs to severe TBI patients within 48 h of injury. METHODS/DESIGN: The study will be conducted in two steps. Step 1 will enrol 42 patients, randomised in a 1:1:1 ratio to receive 80 million MSCs, 160 million MSCs or a placebo to establish safety and identify the most promising dose. Step 2 will enrol an additional 36 patients, randomised in a 1:1 ratio to receive the selected dose of MSCs or placebo. The activity of MSCs will be assessed by quantifying the plasmatic levels of neurofilament light (NfL) at 14 days as a biomarker of neuronal damage. It could be a significant breakthrough if the study demonstrates the safety and efficacy of MSC-based therapy for severe TBI patients. The results of this trial could inform the design of a phase III clinical trial aimed at establishing the efficacy of the first neurorestorative therapy for TBI. DISCUSSION: Overall, the MATRIx trial is a critical step towards developing an effective treatment for TBI, which could significantly improve the lives of millions worldwide affected by this debilitating condition. Trial Registration EudraCT: 2022-000680-49.

Systemic immune response in young and elderly patients after traumatic brain injury.

BACKGROUND: Traumatic brain injury (TBI) is a leading cause of death and long-term disability worldwide. In addition to primary brain damage, systemic immune alterations occur, with evidence for dysregulated immune responses in aggravating TBI outcome and complications. However, immune dysfunction following TBI has been only partially understood, especially in the elderly who represent a substantial proportion of TBI patients and worst outcome. Therefore, we aimed to conduct an in-depth immunological characterization of TBI patients, by evaluating both adaptive (T and B lymphocytes) and innate (NK and monocytes) immune cells of peripheral blood mononuclear cells (PBMC) collected acutely (< 48 h) after TBI in young (18-45 yo) and elderly (> 65 yo) patients, compared to age-matched controls, and also the levels of inflammatory biomarkers. RESULTS: Our data show that young respond differently than elderly to TBI, highlighting the immune unfavourable status of elderly compared to young patients. While in young only CD4 T lymphocytes are activated by TBI, in elderly both CD4 and CD8 T cells are affected, and are induced to differentiate into subtypes with low cytotoxic activity, such as central memory CD4 T cells and memory precursor effector CD8 T cells. Moreover, TBI enhances the frequency of subsets that have not been previously investigated in TBI, namely the double negative CD27- IgD- and CD38-CD24- B lymphocytes, and CD56dim CD16- NK cells, both in young and elderly patients. TBI reduces the production of pro-inflammatory cytokines TNF-α and IL-6, and the expression of HLA-DM, HLA-DR, CD86/B7-2 in monocytes, suggesting a compromised ability to drive a pro-inflammatory response and to efficiently act as antigen presenting cells. CONCLUSIONS: We described the acute immunological response induced by TBI and its relation with injury severity, which could contribute to pathologic evolution and possibly outcome. The focus on age-related immunological differences could help design specific therapeutic interventions based on patients' characteristics.

Accuracy of Manual Intracranial Pressure Recording Compared to a Computerized High-Resolution System: A CENTER-TBI Analysis.

BACKGROUND: Monitoring intracranial pressure (ICP) and cerebral perfusion pressure (CPP) is crucial in the management of the patient with severe traumatic brain injury (TBI). In several institutions ICP and CPP are summarized hourly and entered manually on bedside charts; these data have been used in large observational and interventional trials. However, ICP and CPP may change rapidly and frequently, so data recorded in medical charts might underestimate actual ICP and CPP shifts. The aim of this study was to evaluate the accuracy of manual data annotation for proper capturing of ICP and CPP. For this aim, we (1) compared end-hour ICP and CPP values manually recorded (MR) with values recorded continuously by computerized high-resolution (HR) systems and (2) analyzed whether MR ICP and MR CPP are reliable indicators of the burden of intracranial hypertension and low CPP. METHODS: One hundred patients were included. First, we compared the MR data with the values stored in the computerized system during the first 7 days after admission. For this point-to-point analysis, we calculated the difference between end-hour MR and HR ICP and CPP. Then we analyzed the burden of high ICP (> 20 mm Hg) and low CPP (< 60 mm Hg) measured by the computerized system, in which continuous data were stored, compared with the pressure-time dose based on end-hour measurements. RESULTS: The mean difference between MR and HR end-hour values was 0.02 mm Hg for ICP (SD 3.86 mm Hg) and 1.54 mm Hg for CPP (SD 8.81 mm Hg). ICP > 20 mm Hg and CPP < 60 mm Hg were not detected by MR in 1.6% and 5.8% of synchronized measurements, respectively. Analysis of the pathological ICP and CPP throughout the recording, however, indicated that calculations based on manual recording seriously underestimated the ICP and CPP burden (in 42% and 28% of patients, respectively). CONCLUSIONS: Manual entries fairly represent end-hour HR ICP and CPP. However, compared with a computerized system, they may prove inadequate, with a serious risk of underestimation of the ICP and CPP burden.

Early management of isolated severe traumatic brain injury patients in a hospital without neurosurgical capabilities: a consensus and clinical recommendations of the World Society of Emergency Surgery (WSES).

BACKGROUND: Severe traumatic brain-injured (TBI) patients should be primarily admitted to a hub trauma center (hospital with neurosurgical capabilities) to allow immediate delivery of appropriate care in a specialized environment. Sometimes, severe TBI patients are admitted to a spoke hospital (hospital without neurosurgical capabilities), and scarce data are available regarding the optimal management of severe isolated TBI patients who do not have immediate access to neurosurgical care. METHODS: A multidisciplinary consensus panel composed of 41 physicians selected for their established clinical and scientific expertise in the acute management of TBI patients with different specializations (anesthesia/intensive care, neurocritical care, acute care surgery, neurosurgery and neuroradiology) was established. The consensus was endorsed by the World Society of Emergency Surgery, and a modified Delphi approach was adopted. RESULTS: A total of 28 statements were proposed and discussed. Consensus was reached on 22 strong recommendations and 3 weak recommendations. In three cases, where consensus was not reached, no recommendation was provided. CONCLUSIONS: This consensus provides practical recommendations to support clinician's decision making in the management of isolated severe TBI patients in centers without neurosurgical capabilities and during transfer to a hub center.

Deep Phenotyping of T-Cells Derived From the Aneurysm Wall in a Pediatric Case of Subarachnoid Hemorrhage.

Intracranial aneurysms (IAs) are very rare in children, and the characteristics of the T-cells in the IA wall are largely unknown. A comatose 7-years-old child was admitted to our center because of a subarachnoid hemorrhage due to a ruptured giant aneurysm of the right middle cerebral artery. Two days after the aneurysm clipping the patient was fully awake with left hemiparesis. T-cells from the IA wall and from peripheral blood of this patient were analyzed by multi-dimensional flow cytometry. Unbiased analysis, based on the use of FlowSOM clustering and dimensionality reduction technique UMAP, indicated that there was virtually no overlap between circulating and tissue-infiltrating T-cells. Thus, naïve T-cells and canonical memory T-cells were largely restricted to peripheral blood, while CD4-CD8-T-cells were strongly enriched in the IA wall. The unique CD4+, CD8+ and CD4-CD8-T-cell clusters from the IA wall expressed high levels of CCR5, Granzyme B and CD69, displaying thus characteristics of cytotoxic and tissue-resident effector cells. Low Ki67 expression indicated that they were nevertheless in a resting state. Among regulatory T-cell subsets, Eomes+Tr1-like cells were strongly enriched in the IA wall. Finally, analysis of cytokine producing capacities unveiled that the IA wall contained poly-functional T-cells, which expressed predominantly IFN-γ, TNF and IL-2. CD4+T-cells co-expressed also CD40L, and produced some IL-17, GM-CSF and IL-10. This report provides to our knowledge the first detailed characterization of the human T-cell compartment in the IA wall.

Angiotensin-(1-7) as a Potential Therapeutic Strategy for Delayed Cerebral Ischemia in Subarachnoid Hemorrhage.

Aneurysmal subarachnoid hemorrhage (SAH) is a substantial cause of mortality and morbidity worldwide. Moreover, survivors after the initial bleeding are often subject to secondary brain injuries and delayed cerebral ischemia, further increasing the risk of a poor outcome. In recent years, the renin-angiotensin system (RAS) has been proposed as a target pathway for therapeutic interventions after brain injury. The RAS is a complex system of biochemical reactions critical for several systemic functions, namely, inflammation, vascular tone, endothelial activation, water balance, fibrosis, and apoptosis. The RAS system is classically divided into a pro-inflammatory axis, mediated by angiotensin (Ang)-II and its specific receptor AT1R, and a counterbalancing system, presented in humans as Ang-(1-7) and its receptor, MasR. Experimental data suggest that upregulation of the Ang-(1-7)/MasR axis might be neuroprotective in numerous pathological conditions, namely, ischemic stroke, cognitive disorders, Parkinson's disease, and depression. In the presence of SAH, Ang-(1-7)/MasR neuroprotective and modulating properties could help reduce brain damage by acting on neuroinflammation, and through direct vascular and anti-thrombotic effects. Here we review the role of RAS in brain ischemia, with specific focus on SAH and the therapeutic potential of Ang-(1-7).

Cerebrospinal Fluid and Arterial Acid-Base Equilibrium of Spontaneously Breathing Patients with Aneurismal Subarachnoid Hemorrhage.

BACKGROUND: Hyperventilation resulting in hypocapnic alkalosis (HA) is frequently encountered in spontaneously breathing patients with acute cerebrovascular conditions. The underlying mechanisms of this respiratory response have not been fully elucidated. The present study describes, applying the physical-chemical approach, the acid-base characteristics of cerebrospinal fluid (CSF) and arterial plasma of spontaneously breathing patients with aneurismal subarachnoid hemorrhage (SAH) and compares these results with those of control patients. Moreover, it investigates the pathophysiologic mechanisms leading to HA in SAH. METHODS: Patients with SAH admitted to the neurological intensive care unit and patients (American Society of Anesthesiologists physical status of 1 and 2) undergoing elective surgery under spinal anesthesia were enrolled. CSF and arterial samples were collected simultaneously. Electrolytes, strong ion difference (SID), partial pressure of carbon dioxide (PCO2), weak noncarbonic acids (ATOT), and pH were measured in CSF and arterial blood samples. RESULTS: Twenty spontaneously breathing patients with SAH and 25 controls were enrolled. The CSF of patients with SAH, as compared with controls, was characterized by a lower SID (23.1 ± 2.3 vs. 26.5 ± 1.4 mmol/L, p < 0.001) and PCO2 (40 ± 4 vs. 46 ± 3 mm Hg, p < 0.001), whereas no differences in ATOT (1.2 ± 0.5 vs. 1.2 ± 0.2 mmol/L, p = 0.95) and pH (7.34 ± 0.06 vs. 7.35 ± 0.02, p = 0.69) were observed. The reduced CSF SID was mainly caused by a higher lactate concentration (3.3 ± 1.3 vs. 1.4 ± 0.2 mmol/L, p < 0.001). A linear association (r = 0.71, p < 0.001) was found between CSF SID and arterial PCO2. A higher proportion of patients with SAH were characterized by arterial HA, as compared with controls (40 vs. 4%, p = 0.003). A reduced CSF-to-plasma difference in PCO2 was observed in nonhyperventilating patients with SAH (0.4 ± 3.8 vs. 7.8 ± 3.7 mm Hg, p < 0.001). CONCLUSIONS: Patients with SAH have a reduction of CSF SID due to an increased lactate concentration. The resulting localized acidifying effect is compensated by CSF hypocapnia, yielding normal CSF pH values and resulting in a higher incidence of arterial HA.

Early management of patients with aneurysmal subarachnoid hemorrhage in a hospital with neurosurgical/neuroendovascular facilities: a consensus and clinical recommendations of the Italian Society of Anesthesia and Intensive Care (SIAARTI)-Part 1.

BACKGROUND: Issues remain on the optimal management of subarachnoid hemorrhage (SAH) patients once they are admitted to the referring center, before and after the aneurysm treatment. To address these issues, we created a consensus of experts endorsed by the Italian Society of Anesthesia and Intensive Care (SIAARTI). In this manuscript, we aim to provide a list of experts' recommendations regarding the early management of SAH patients from hospital admission, in a center with neurosurgical/neuro-endovascular facilities, until securing of the bleeding aneurysm. METHODS: A multidisciplinary consensus panel composed of 24 physicians selected for their established clinical and scientific expertise in the acute management of SAH patients with different background (anesthesia/intensive care, neurosurgery, and interventional neuroradiology) was created. A modified Delphi approach was adopted. RESULTS: Among 19 statements discussed. The consensus was reached on 18 strong recommendations. In one case, consensus could not be agreed upon and no recommendation was provided. CONCLUSIONS: This consensus provides practical recommendations for the management of SAH patients in hospitals with neurosurgical/neuroendovascular facilities until aneurysm securing. It is intended to support clinician's decision-making and not to mandate a standard of practice.

Early management of patients with aneurysmal subarachnoid hemorrhage in a hospital with neurosurgical/neuroendovascular facilities: a consensus and clinical recommendations of the Italian Society of Anesthesia and Intensive Care (SIAARTI)-part 2.

BACKGROUND: Questions remain on the optimal management of subarachnoid hemorrhage (SAH) patients once they are admitted to the referring center, before and after the aneurysm treatment. To address these issues, we created a consensus of experts endorsed by the Italian Society of Anesthesia and Intensive Care (SIAARTI) to provide clinical guidance regarding this topic. Specifically, in this manuscript (part 2), we aim to provide a list of experts' recommendations regarding the management of SAH patients in a center with neurosurgical/neuroendovascular facilities after aneurysm treatment. METHODS: A multidisciplinary consensus panel composed by 24 physicians selected for their established clinical and scientific expertise in the acute management of SAH patients with different specializations (anesthesia/intensive care, neurosurgery, and interventional neuroradiology) was created. A modified Delphi approach was adopted. RESULTS: A total of 33 statements were discussed, voted, and approved. Consensus was reached on 30 recommendations (28 strong and 2 weak). In 3 cases, where consensus could not be agreed upon, no recommendation was provided. CONCLUSIONS: This consensus provides practical recommendations (and not mandatory standard of practice) to support clinician's decision-making in the management of SAH patients in centers with neurosurgical/neuroendovascular facilities after aneurysm securing.

Brain Temperature Influences Intracranial Pressure and Cerebral Perfusion Pressure After Traumatic Brain Injury: A CENTER-TBI Study.

BACKGROUND: After traumatic brain injury (TBI), fever is frequent. Brain temperature (BT), which is directly linked to body temperature, may influence brain physiology. Increased body and/or BT may cause secondary brain damage, with deleterious effects on intracranial pressure (ICP), cerebral perfusion pressure (CPP), and outcome. METHODS: Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI), a prospective multicenter longitudinal study on TBI in Europe and Israel, includes a high resolution cohort of patients with data sampled at a high frequency (from 100 to 500 Hz). In this study, simultaneous BT, ICP, and CPP recordings were investigated. A mixed-effects linear model was used to examine the association between different BT levels and ICP. We additionally focused on changes in ICP and CPP during the episodes of BT changes (Δ BT ≥ 0.5 °C lasting from 15 min to 3 h) up or downward. The significance of ICP and CPP variations was estimated with the paired samples Wilcoxon test (also known as Wilcoxon signed-rank test). RESULTS: Twenty-one patients with 2,435 h of simultaneous BT and ICP monitoring were studied. All patients reached a BT of 38 °C and experienced at least one episode of ICP above 20 mm Hg. The linear mixed-effects model revealed an association between BT above 37.5 °C and higher ICP levels that was not confirmed for lower BT. We identified 149 episodes of BT changes. During BT elevations (n = 79) ICP increased, whereas CPP was reduced; opposite ICP and CPP variations occurred during episodes of BT reduction (n = 70). All these changes were of moderate clinical relevance (increase of ICP of 4.5 and CPP decrease of 7.5 mm Hg for BT rise, and ICP reduction of 1.7 and CPP elevation of 3.7 mm Hg during BT defervescence), even if statistically significant (p < 0.0001). It has to be noted, however, that a number of therapeutic interventions against intracranial hypertension was documented during those episodes. CONCLUSIONS: Patients after TBI usually develop BT > 38 °C soon after the injury. BT may influence brain physiology, as reflected by ICP and CPP. An association between BT exceeding 37.5 °C and a higher ICP was identified but not confirmed for lower BT ranges. The relationship between BT, ICP, and CPP become clearer during rapid temperature changes. During episodes of temperature elevation, BT seems to have a significant impact on ICP and CPP.

Early management of patients with aneurysmal subarachnoid hemorrhage in a hospital without neurosurgical/neuroendovascular facilities: a consensus and clinical recommendations of the Italian Society of Anesthesia and Intensive Care (SIAARTI).

BACKGROUND: The immediate management of subarachnoid hemorrhage (SAH) patients in hospitals without neurosurgical/neurointerventional facilities and their transfer to a specialized center is challenging and not well covered in existing guidelines. To address these issues, we created a consensus of experts endorsed by the Italian Society of Anesthesia and Intensive Care (SIAARTI) to provide clinical guidance. METHODS: A multidisciplinary consensus panel composed by 19 physicians selected for their established clinical and scientific expertise in the acute management of SAH patients with different specializations (anesthesia/intensive care, neurosurgery and interventional neuroradiology) was created. A modified Delphi approach was adopted. RESULTS: A total of 14 statements have been discussed. Consensus was reached on 11 strong recommendations and 2 weak recommendations. In one case, where consensus could not be agreed upon, no recommendation could be provided. CONCLUSIONS: Management of SAH in a non-specialized setting and early transfer are difficult and may have a critical impact on outcome. Clinical advice, based on multidisciplinary consensus, might be helpful. Our recommendations cover most, but not all, topics of clinical relevance.

Patient-specific ICP Epidemiologic Thresholds in Adult Traumatic Brain Injury: A CENTER-TBI Validation Study.

BACKGROUND: Patient-specific epidemiologic intracranial pressure (ICP) thresholds in adult traumatic brain injury (TBI) have emerged, using the relationship between pressure reactivity index (PRx) and ICP, displaying stronger association with outcome over existing guideline thresholds. The goal of this study was to explore this relationship in a multi-center cohort in order to confirm the previous finding. METHODS: Using the Collaborative European Neuro Trauma Effectiveness Research in TBI (CENTER-TBI) high-resolution intensive care unit cohort, we derived individualized epidemiologic ICP thresholds for each patient using the relationship between PRx and ICP. Mean hourly dose of ICP was calculated for every patient for the following thresholds: 20, 22 mm Hg and the patient's individual ICP threshold. Univariate logistic regression models were created comparing mean hourly dose of ICP above thresholds to dichotomized outcome at 6 to 12 months, based on Glasgow Outcome Score-Extended (GOSE) (alive/dead-GOSE≥2/GOSE=1; favorable/unfavorable-GOSE 5 to 8/GOSE 1 to 4, respectively). RESULTS: Individual thresholds were identified in 65.3% of patients (n=128), in keeping with previous results (23.0±11.8 mm Hg [interquartile range: 14.9 to 29.8 mm Hg]). Mean hourly dose of ICP above individual threshold provides superior discrimination (area under the receiver operating curve [AUC]=0.678, P=0.029) over mean hourly dose above 20 mm Hg (AUC=0.509, P=0.03) or above 22 mm Hg (AUC=0.492, P=0.035) on univariate analysis for alive/dead outcome at 6 to 12 months. The AUC for mean hourly dose above individual threshold trends to higher values for favorable/unfavorable outcome, but fails to reach statistical significance (AUC=0.610, P=0.060). This was maintained when controlling for baseline admission characteristics. CONCLUSIONS: Mean hourly dose of ICP above individual epidemiologic ICP threshold has stronger associations with mortality compared with the dose above Brain Trauma Foundation defined thresholds of 20 or 22 mm Hg, confirming prior findings. Further studies on patient-specific epidemiologic ICP thresholds are required.

Optic Nerve Sheath Diameter is not Related to Intracranial Pressure in Subarachnoid Hemorrhage Patients.

BACKGROUND: Intracranial pressure (ICP) monitoring is essential after subarachnoid hemorrhage (SAH) to prevent secondary brain insults and to tailor individualized treatments. Optic nerve sheath diameter (ONSD), measured using ultrasound (US), could serve as a noninvasive bedside tool to estimate ICP, avoiding the risks of hemorrhage or infection related to intracranial catheters. The aims of this study were twofold: first, to explore the reliability of US for measuring ONSD; second, to establish whether the US-ONSD can be considered a proxy for ICP in SAH patients early after bleeding. For the first aim, we compared the ONSD measurements given by magnetic resonance imaging (MRI-ONSD) with the US-ONSD findings. For the second aim, we analyzed the relationship between US-ONSD measurements and ICP values. METHODS: Adult patients with diagnosis of aneurysmal SAH and external ventricular drainage system (EVD) were included. Ten patients were examined by MRI to assess ONSD, and the results were compared to the diameter given by US. In 20 patients, the US-ONSD values were related to ICP measured simultaneously through EVD. In ten of these patients, we explored the changes in the US-ONSD at the time of controlled and fairly rapid changes in ICP after cerebrospinal fluid (CSF) drainage. RESULTS: US-ONSD measurements at the bedside were accurate, very similar to the diameters measured by MRI (the mean difference in the Bland-Altman plot was 0.08 mm, 95% limits of agreement: - 1.13; + 1.23 mm). No clear relationship was detectable between the ICP and US-ONSD, and a linear regression model showed an angular coefficient very close to 0 (p > 0.05). US-ONSD and ICP values were in agreement after CSF drainage and shifts in ICP in a limited number of patients. CONCLUSIONS: US-ONSD measurement does not accurately estimate ICP in SAH patients in the intensive care unit.

Changing care pathways and between-center practice variations in intensive care for traumatic brain injury across Europe: a CENTER-TBI analysis.

PURPOSE: To describe ICU stay, selected management aspects, and outcome of Intensive Care Unit (ICU) patients with traumatic brain injury (TBI) in Europe, and to quantify variation across centers. METHODS: This is a prospective observational multicenter study conducted across 18 countries in Europe and Israel. Admission characteristics, clinical data, and outcome were described at patient- and center levels. Between-center variation in the total ICU population was quantified with the median odds ratio (MOR), with correction for case-mix and random variation between centers. RESULTS: A total of 2138 patients were admitted to the ICU, with median age of 49 years; 36% of which were mild TBI (Glasgow Coma Scale; GCS 13-15). Within, 72 h 636 (30%) were discharged and 128 (6%) died. Early deaths and long-stay patients (> 72 h) had more severe injuries based on the GCS and neuroimaging characteristics, compared with short-stay patients. Long-stay patients received more monitoring and were treated at higher intensity, and experienced worse 6-month outcome compared to short-stay patients. Between-center variations were prominent in the proportion of short-stay patients (MOR = 2.3, p < 0.001), use of intracranial pressure (ICP) monitoring (MOR = 2.5, p < 0.001) and aggressive treatments (MOR = 2.9, p < 0.001); and smaller in 6-month outcome (MOR = 1.2, p = 0.01). CONCLUSIONS: Half of contemporary TBI patients at the ICU have mild to moderate head injury. Substantial between-center variations exist in ICU stay and treatment policies, and less so in outcome. It remains unclear whether admission of short-stay patients represents appropriate prudence or inappropriate use of clinical resources.