Variability in Serum Sodium Concentration and Prognostic Significance in Severe Traumatic Brain Injury: A Multicenter Observational Study

Extracranial Effects of Traumatic Brain Injury: A Narrative Review

BACKGROUND

Traumatic brain injury (TBI) is often associated with other injuries and comorbidities. However, even isolated TBI directly leads to dysfunction in multiple body systems outside the central nervous system. These extracranial effects of TBI target systems including the autonomic nervous, cardiovascular, renal, pulmonary, immune, gastrointestinal, and hemostasis systems, as well as causing significant alteration to systemic metabolism.

AIM

This review is intended to outline the effects of TBI on other body systems, and place these in context with treatment considerations for these patients.

SIGNIFICANCE

Systemic effects of TBI have implications for acute and critical care management of patients with TBI, including pharmacologic treatment. They also affect treatment decisions in chronic TBI care, as well as TBI-unrelated routine medical care for patients with chronic TBI. In addition, extracranial effects of TBI should be considered in research settings.

CONCLUSIONS

It is important for clinicians and researchers to be aware of these extracranial effects, and consider their effects on pathology, treatment decisions, and interpretation of research findings.

The impact of serum sodium variability on surgical patients with aneurysmal subarachnoid hemorrhage

Currently, limited evidence exists on the impact of serum sodium variability in patients with aneurysmal subarachnoid hemorrhage (SAH) who underwent surgical clipping. We aimed to perform a detailed examination of the relationship between sodium variability and mortality in these patients. We conducted a cohort study including adult patients with aneurysmal SAH who underwent surgical clipping at a university hospital. Propensity score matching (PSM) was used to match patients' baseline characteristics. We evaluated the association between serum sodium standard deviation and mortality. Net reclassification improvement was calculated to assess and compare the reclassification capacity of different models. Trends in serum sodium over time were detected using linear mixed-effects models. Of 563 aneurysmal SAH patients who underwent surgical clipping during the study period, the average age was 56.87 ± 10.81 years. The serum sodium standard deviation was 4.24 [2.65-5.82] mmol/L. Patients with high sodium variability had significantly higher odds of mortality (adjusted odds ratio [aOR]: 1.93, 95% confidence interval [CI]: 1.01 to 3.68; P = 0.045). PSM analysis showed similar results (aOR: 2.23, 95% CI: 1.10 to 4.99; P = 0.045). Additionally, an increase in serum sodium of more than 5 mmol/L was significantly associated with mortality (aOR: 3.46, 95% CI: 1.26 to 9.20; P = 0.016) in a linear dose-response pattern. High serum sodium variability and an increase in serum sodium of more than 5 mmol/L were independent predictive factors of mortality in aneurysmal SAH patients who underwent surgical clipping. Thus, even mild changes in sodium levels warrant close attention.

Natremia Significantly Influences the Clinical Outcomes in Patients with Severe Traumatic Brain Injury

Objective: Fluctuations in sodium levels (SLs) may increase mortality, severity, and prolonged length of stay (LOS) in critically ill patients. We aim to study the effect of SL on various clinical outcomes in patients with severe traumatic brain injury (TBI). Methods: This is a single-center, retrospective study of patients with severe TBI from 1 January 2020 to 31 December 2023, inclusive. Patients were identified using Abbreviated Injury Severity (AIS) scores and International Classification of Diseases (ICD) injury descriptions. Result: Variations in hospital (H) admission SLs were statistically significant across four age ranges (pediatric, young adult, older adults, and elderly). Intensive care unit (ICU) admission, H discharge, and death also showed significance. A statistical difference was noted in ICU discharge levels while comparing blunt versus penetrating injury. We found statistically significant differences in SLs at H admission, ICU admission, and ICU discharge when compared to the Injury Severity Score (ISS) and the Glasgow Coma Scale (GCS) at admission. A linear regression analysis revealed a statistically significant positive correlation between ICU admission SLs and ISS. We discovered statistically significant differences when comparing ICU admission levels to H LOS, ventilator days, and mortality. Conclusions: SL upon ICU admission is correlated with ISS, GCS, and mortality rates. The elevated admission SL was linked to adverse hospital outcomes, including prolonged LOS at the H, ICU, and mechanical ventilation. Moreover, variability in serum SLs is independently associated with mortality throughout the hospital stay, irrespective of the absolute serum sodium concentration.

Effect of continuous hypertonic saline infusion on clinical outcomes in patients with traumatic brain injury

Osmotic therapy has been recognized as an important treatment option for patients with traumatic brain injury (TBI). Nevertheless, the effect of hypertonic saline (HTS) remains unknown, as findings are primarily based on a large database. This study aimed to elucidate the effect of HTS on the clinical outcomes of patients with TBI admitted to the intensive care unit (ICU). We retrospectively identified patients with moderate-to-severe TBI from two public databases: Medical Information Mart for Intensive Care (MIMIC)-IV and eICU Collaborative Research Database (eICU-CRD). A marginal structural Cox model (MSCM) was used, with time-dependent variates designed to reflect exposure over time during ICU stay. Trajectory modeling based on the intracranial pressure evolution pattern allowed for the identification of subgroups. Overall, 130 (6.65%) of 1955 eligible patients underwent HTS. MSCM indicated that the HTS significantly associated with higher infection complications (e.g., urinary tract infection (HR 1.88, 95% CI 1.26-2.81, p = 0.002)) and increased ICU LOS (HR 2.02, 95% CI 1.71-2.40, p < 0.001). A protective effect of HTS on GCS was found in subgroups with medium and low intracranial pressure. Our study revealed no significant difference in mortality between patients who underwent HTS and those who did not. Increased occurrence rates of infection and electrolyte imbalance are inevitable outcomes of continuous HTS infusion. Although the study suggests slight beneficial effects, including better neurological outcomes, these results warrant further validation.

Clinical descriptors of disease trajectories in patients with traumatic brain injury in the intensive care unit (CENTER-TBI): a multicentre observational cohort study

BACKGROUND

Patients with traumatic brain injury are a heterogeneous population, and the most severely injured individuals are often treated in an intensive care unit (ICU). The primary injury at impact, and the harmful secondary events that can occur during the first week of the ICU stay, will affect outcome in this vulnerable group of patients. We aimed to identify clinical variables that might distinguish disease trajectories among patients with traumatic brain injury admitted to the ICU.

METHODS

We used data from the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) prospective observational cohort study. We included patients aged 18 years or older with traumatic brain injury who were admitted to the ICU at one of the 65 CENTER-TBI participating centres, which range from large academic hospitals to small rural hospitals. For every patient, we obtained pre-injury data and injury features, clinical characteristics on admission, demographics, physiological parameters, laboratory features, brain biomarkers (ubiquitin carboxy-terminal hydrolase L1 [UCH-L1], S100 calcium-binding protein B [S100B], tau, neurofilament light [NFL], glial fibrillary acidic protein [GFAP], and neuron-specific enolase [NSE]), and information about intracranial pressure lowering treatments during the first 7 days of ICU stay. To identify clinical variables that might distinguish disease trajectories, we applied a novel clustering method to these data, which was based on a mixture of probabilistic graph models with a Markov chain extension. The relation of clusters to the extended Glasgow Outcome Scale (GOS-E) was investigated.

FINDINGS

Between Dec 19, 2014, and Dec 17, 2017, 4509 patients with traumatic brain injury were recruited into the CENTER-TBI core dataset, of whom 1728 were eligible for this analysis. Glucose variation (defined as the difference between daily maximum and minimum glucose concentrations) and brain biomarkers (S100B, NSE, NFL, tau, UCH-L1, and GFAP) were consistently found to be the main clinical descriptors of disease trajectories (ie, the leading variables contributing to the distinguishing clusters) in patients with traumatic brain injury in the ICU. The disease trajectory cluster to which a patient was assigned in a model was analysed as a predictor together with variables from the IMPACT model, and prediction of both mortality and unfavourable outcome (dichotomised GOS-E ≤4) was improved.

INTERPRETATION

First-day ICU admission data are not the only clinical descriptors of disease trajectories in patients with traumatic brain injury. By analysing temporal variables in our study, variation of glucose was identified as the most important clinical descriptor that might distinguish disease trajectories in the ICU, which should direct further research. Biomarkers of brain injury (S100B, NSE, NFL, tau, UCH-L1, and GFAP) were also top clinical descriptors over time, suggesting they might be important in future clinical practice.

FUNDING

European Union 7th Framework program, Hannelore Kohl Stiftung, OneMind, Integra LifeSciences Corporation, and NeuroTrauma Sciences.

Identification of Demographic and Clinical Prognostic Factors in Traumatic Intraventricular Hemorrhage

BACKGROUND

The presence of traumatic intraventricular hemorrhage (tIVH) following traumatic brain injury (TBI) is associated with worse neurological outcome. The mechanisms by which patients with tIVH have worse outcome are not fully understood and research is ongoing, but foundational studies that explore prognostic factors within tIVH populations are also lacking. This study aimed to further identify and characterize demographic and clinical variables within a subset of patients with TBI and tIVH that may be implicated in tIVH outcome.

METHODS

In this observational study, we reviewed a large prospective TBI database to determine variables present on admission that predicted neurological outcome 6 months after injury. A review of 7,129 patients revealed 211 patients with tIVH on admission and 6-month outcome data. Hypothesized risk factors were tested in univariate analyses with significant variables (p < 0.05) included in logistic and linear regression models. Following the addition of either the Rotterdam computed tomography or Glasgow Coma Scale (GCS) score, we employed a backward selection process to determine significant variables in each multivariate model.

RESULTS

Our study found that that hypotension (odds ratio [OR] = 0.35, 95% confidence interval [CI] = 0.13-0.94, p = 0.04) and the hemoglobin level (OR = 1.33, 95% CI = 1.09-1.63, p = 0.006) were significant predictors in the Rotterdam model, whereas only the hemoglobin level (OR = 1.29, 95% CI = 1.06-1.56, p = 0.01) was a significant predictor in the GCS model.

CONCLUSIONS

This study represents one of the largest investigations into prognostic factors for patients with tIVH and demonstrates that admission hemoglobin level and hypotension are associated with outcomes in this patient population. These findings add value to established prognostic scales, could inform future predictive modeling studies, and may provide potential direction in early medical management of patients with tIVH.

Trauma-related electrolyte disturbances: From resuscitation to rhabdomyolysis

Traumatic injury results in drastic changes to a patient's normal physiology. The hormonal stress response, as well as some treatment strategies, lead to significant disruptions in electrolyte homeostasis that are important for clinicians to understand. In addition, advances in fluid resuscitation and modern transfusion practices have led to their own unique set of consequences, which we are just beginning to appreciate. Special attention is placed on rhabdomyolysis, as this distinct entity represents an extreme example of injury induced electrolyte derangements. This review describes the physiologic response to trauma and highlights some of the important electrolyte abnormalities that can be encountered while caring for the injured patient.