Hierarchical log linear analysis of admission blood parameters and clinical outcome following traumatic brain injury

Traumatic Brain Injury, Electrolyte Levels, and Associated Outcomes: A Systematic Review

INTRODUCTION

Although it has been established that electrolyte abnormalities are a consequence of traumatic brain injury (TBI), the degree to which electrolyte imbalances impact patient outcomes has not been fully established. We aim to determine the impact of sodium, potassium, calcium, and magnesium abnormalities on outcomes in patients with TBI.

METHODS

Four databases were searched for studies related to the impact of electrolyte abnormalities on outcomes for TBI patients. Outcomes of interest were rates of mortality, Glasgow Outcome Scale (GOS), and intensive care unit length of stay (ICU-LOS). The search included studies published up to July 21, 2022. Articles were then screened and included if they met inclusion and exclusion criteria.

RESULTS

In total, fourteen studies met inclusion and exclusion criteria for analysis in this systematic review. In patients with TBI, an increased mortality rate was associated with hypernatremia, hypokalemia, and hypocalcemia in the majority of studies. Both hyponatremia and hypomagnesemia were associated with worse GOS at 6 months. Whereas, both hyponatremia and hypernatremia were associated with increased ICU-LOS. There was no evidence to suggest other electrolyte imbalances were associated with either GOS or ICU-LOS.

CONCLUSIONS

Hyponatremia and hypomagnesemia were associated with worse GOS. Hypernatremia was associated with increased mortality and ICU-LOS. Hypokalemia and hypocalcemia were associated with increased mortality. Given these findings, future practice guidelines should consider the effects of electrolytes' abnormalities on outcomes in TBI patients prior to establishing management strategies.

Using technology to understand how therapist variables are associated with clinical outcomes in IAPT

The UK’s Improving Access to Psychological Therapy Programme (IAPT) has improved transparency of primary mental health care in relation to the mandatory reporting of clinical outcomes. However, the data reveal a significant variance in outcomes. These findings have led to a growing body of research investigating to what extent therapist variables account for the difference in clinical outcomes. Previous studies have not had access to sufficient recordings or transcripts of therapy sessions in order to fully address this question. The purpose of this study was to use therapy transcripts derived from internet enabled cognitive behavioural therapy (CBT) treatment sessions in order to investigate whether and how therapist variables are associated with clinical outcome. A hierarchical log-linear analysis examined the relationship between therapist/patient variables and clinical outcome. Therapist fidelity to the CBT model and associated adherence to an evidence-based protocol were significantly related to clinical outcome. A graphical representation of the statistical model suggests that patient recovery is directly linked with fidelity and indirectly with adherence, after adjusting for patient attributes of age, gender and clinical presentation. Corroborating previous research, therapist competence and adherence to an evidence-based treatment protocol appear to be important in improving outcomes. These findings have implications for the continuing professional development of qualified therapists, potentially reinforcing the importance of reducing therapist drift.

Key learning aims

(1)

Distribution of Laboratory Parameters in Trauma Population

Background:

Biochemical laboratory investigations help plan optimum management and communication in short- as well as long-term outcome to trauma victims.

Objective:

To assess the status of real-time values of biochemical laboratory investigations of different trauma patients and their association with overall mortality.

Materials and Methods:

Data based on prospective, observational registry of “Towards Improved Trauma Care Outcomes” (TITCO) from four Indian city hospitals. Hemoglobin, hematocrit, random blood sugar, blood urea nitrogen (BUN), and serum creatinine of patients on admission were recorded. Logistic regression was applied with all biochemical investigation as independent variable and overall mortality as dependent variable.

Results:

Among 17047 trauma patients, 3456 with available laboratory result details were considered for this study. Overall mortality was 20% (range 14%–21%). For the higher laboratory results, value mortality was 21%–70%, with highest death (70%) for higher hemoglobin patients, followed by hematocrit (44%) and then creatinine (43%). Odds of high hemoglobin compared to normal were 15.20; odds of higher and lower of normal creatinine were 3.80 and 1.65 and for BUN were 2.17 and 1.92, respectively. Gender-wise significant difference was in overall female mortality (29%)% compared males (18%). Similar differences were replicated with results of each laboratory tests.

Conclusion:

The study ascertained the composite additional explanatory values of laboratory parameters in predicting outcome among injured patients in our population from Indian settings.

Systemic, local, and imaging biomarkers of brain injury: more needed, and better use of those already established?

Much progress has been made over the past two decades in the treatment of severe acute brain injury, including traumatic brain injury and subarachnoid hemorrhage, resulting in a higher proportion of patients surviving with better outcomes. This has arisen from a combination of factors. These include improvements in procedures at the scene (pre-hospital) and in the hospital emergency department, advances in neuromonitoring in the intensive care unit, both continuously at the bedside and intermittently in scans, evolution and refinement of protocol-driven therapy for better management of patients, and advances in surgical procedures and rehabilitation. Nevertheless, many patients still experience varying degrees of long-term disabilities post-injury with consequent demands on carers and resources, and there is room for improvement. Biomarkers are a key aspect of neuromonitoring. A broad definition of a biomarker is any observable feature that can be used to inform on the state of the patient, e.g., a molecular species, a feature on a scan, or a monitoring characteristic, e.g., cerebrovascular pressure reactivity index. Biomarkers are usually quantitative measures, which can be utilized in diagnosis and monitoring of response to treatment. They are thus crucial to the development of therapies and may be utilized as surrogate endpoints in Phase II clinical trials. To date, there is no specific drug treatment for acute brain injury, and many seemingly promising agents emerging from pre-clinical animal models have failed in clinical trials. Large Phase III studies of clinical outcomes are costly, consuming time and resources. It is therefore important that adequate Phase II clinical studies with informative surrogate endpoints are performed employing appropriate biomarkers. In this article, we review some of the available systemic, local, and imaging biomarkers and technologies relevant in acute brain injury patients, and highlight gaps in the current state of knowledge.

Effect of rosuvastatin on cytokines after traumatic head injury

Object

The favorable effect of statin treatment after traumatic brain injury (TBI) has been shown in animal studies and is probably true in humans as well. The objective of this study was to determine whether acute statin treatment following TBI could reduce inflammatory cytokines and improve functional outcomes in humans.

Methods

The authors performed a double-blind randomized clinical trial in patients with moderate to severe TBI. Exclusion criteria were as follows: prior severe disability; use of modifiers of statin metabolism; multisystem trauma; prior use of mannitol, barbiturates, corticosteroids, or calcium channel blockers; isolated brainstem lesions; allergy to statins; previous hepatopathy or myopathy; previous treatment at another clinic; and pregnancy. Patients were randomly selected to receive 20 mg of rosuvastatin or placebo for 10 days. The main goal was to determine the effect of rosuvastatin on plasma levels of tumor necrosis factor–α, interleukin (IL)–1β, IL-6, and IL-10 after 72 hours of TBI. Amnesia, disorientation, and disability were assessed 3 and 6 months after TBI.

Results

Thirty-six patients were analyzed according to intention-to-treat analysis; 19 patients received rosuvastatin and 17 received placebo. The best-fit mixed model showed a significant effect of rosuvastatin on the reduction of tumor necrosis factor–α levels (p = 0.004). Rosuvastatin treatment did not appear to affect the levels of IL-1β, IL-6, and IL-10. The treatment was associated with a reduction in disability scores (p = 0.03), indicating a favorable functional outcome. Life-threatening adverse effects were not observed.

Conclusions

The authors' data suggest that statins may induce an antiinflammatory effect and may promote recovery after TBI. The role of statins in TBI therapy should be confirmed in larger clinical trials. Clinical trial registration no.: NCT00990028.

Multivariate outcome prediction in traumatic brain injury with focus on laboratory values

Traumatic brain injury (TBI) is a major cause of morbidity and mortality. Identifying factors relevant to outcome can provide a better understanding of TBI pathophysiology, in addition to aiding prognostication. Many common laboratory variables have been related to outcome but may not be independent predictors in a multivariate setting. In this study, 757 patients were identified in the Karolinska TBI database who had retrievable early laboratory variables. These were analyzed towards a dichotomized Glasgow Outcome Scale (GOS) with logistic regression and relevance vector machines, a non-linear machine learning method, univariately and controlled for the known important predictors in TBI outcome: age, Glasgow Coma Score (GCS), pupil response, and computed tomography (CT) score. Accuracy was assessed with Nagelkerke's pseudo R². Of the 18 investigated laboratory variables, 15 were found significant (p<0.05) towards outcome in univariate analyses. In contrast, when adjusting for other predictors, few remained significant. Creatinine was found an independent predictor of TBI outcome. Glucose, albumin, and osmolarity levels were also identified as predictors, depending on analysis method. A worse outcome related to increasing osmolarity may warrant further study. Importantly, hemoglobin was not found significant when adjusted for post-resuscitation GCS as opposed to an admission GCS, and timing of GCS can thus have a major impact on conclusions. In total, laboratory variables added an additional 1.3-4.4% to pseudo R².

Principal component analysis of the cytokine and chemokine response to human traumatic brain injury

There is a growing realisation that neuro-inflammation plays a fundamental role in the pathology of Traumatic Brain Injury (TBI). This has led to the search for biomarkers that reflect these underlying inflammatory processes using techniques such as cerebral microdialysis. The interpretation of such biomarker data has been limited by the statistical methods used. When analysing data of this sort the multiple putative interactions between mediators need to be considered as well as the timing of production and high degree of statistical co-variance in levels of these mediators. Here we present a cytokine and chemokine dataset from human brain following human traumatic brain injury and use principal component analysis and partial least squares discriminant analysis to demonstrate the pattern of production following TBI, distinct phases of the humoral inflammatory response and the differing patterns of response in brain and in peripheral blood. This technique has the added advantage of making no assumptions about the Relative Recovery (RR) of microdialysis derived parameters. Taken together these techniques can be used in complex microdialysis datasets to summarise the data succinctly and generate hypotheses for future study.

Cytokines and innate inflammation in the pathogenesis of human traumatic brain injury

There is an increasing recognition that following traumatic brain injury, a cascade of inflammatory mediators is produced, and contributes to the pathological consequences of central nervous system injury. This review summarises the key literature from pre-clinical models that underlies our understanding of innate inflammation following traumatic brain injury before focussing on the growing evidence from human studies. In addition, the underlying molecular mediators responsible for blood brain barrier dysfunction have been discussed. In particular, we have highlighted the different sampling methodologies available and the difficulties in interpreting human data of this sort. Ultimately, understanding the innate inflammatory response to traumatic brain injury may provide a therapeutic avenue in the treatment of central nervous system disease.

The cytokine response to human traumatic brain injury: temporal profiles and evidence for cerebral parenchymal production

The role of neuroinflammation is increasingly being recognised in a diverse range of cerebral pathologies, including traumatic brain injury (TBI). We used cerebral microdialysis and paired arterial and jugular bulb plasma sampling to characterise the production of 42 cytokines after severe TBI in 12 patients over 5 days. We compared two microdialysis perfusates in six patients: central nervous system perfusion fluid and 3.5% human albumin solution (HAS); 3.5% HAS has a superior fluid recovery (95.8 versus 83.3%), a superior relative recovery in 18 of 42 cytokines (versus 8 of 42), and a qualitatively superior recovery profile. All 42 cytokines were recovered from the human brain. Sixteen cytokines showed a stereotyped temporal peak, at least twice the median value for that cytokine over the monitoring period; day 1: tumour necrosis factor, interleukin (IL)7, IL8, macrophage inflammatory protein (MIP)1α, soluble CD40 ligand, GRO, IL1β, platelet derived growth factor (PDGF)-AA, MIP1β, RANTES; day 2: IL1 receptor antagonist (ra). IL6, granulocyte-colony stimulating factor (G-CSF), chemokine CXC motif ligand 10 (IP10); days 4 to 5: IL12p70, IL10. Brain extracellular fluid concentrations were significantly higher than plasma concentrations for 19 cytokines: basic fibroblast growth factor (FGF2), G-CSF, IL1α, IL1β, IL1ra, IL3, IL6, IL8, IL10, IL12p40, IL12p70, IP10, monocyte chemotactic protein (MCP)1, MCP3, MIP1α, MIP1β, PDGF-AA, transforming growth factor (TGF)α and vascular endothelial growth factor. No clear arterio-jugular venous gradients were apparent. These data provide evidence for the cerebral production of these cytokines and show a stereotyped temporal pattern after TBI.