Severe traumatic brain injury management and clinical outcome using the Lund concept

Cerebrovascular Pressure Reactivity Measures: Index Comparison and Clinical Outcome in Patients With Traumatic Brain Injury Treated According to an Intracranial Pressure-Focused Management: Rejection of the Null Hypothesis

The aim was to investigate whether the pressure reactivity indices PRx, long-PRx (L-PRx), and pressure reactivity (PR) are interchangeable as measures of vascular reactivity, and whether they correlate with clinical outcome when an intracranial pressure (ICP)-targeted treatment regimen is applied in patients with traumatic brain injury (TBI). Patients with TBI (n = 29) that arrived at the hospital within 24 h of injury were included. PRx and L-PRx were derived from Pearson correlations between mean arterial pressure (MAP) and ICP over a short- and long-time interval. PR was the regression coefficient between the hourly mean values of ICP and MAP. Indices were compared to each other, parameters at admission, and outcome assessed by the extended Glasgow Outcome Scale-Extended (GOSE) at 6 and 12 months. PRx and L-PRx had the strongest correlation with each other (R = 0.536, p < 0.01). A correlation was also noted between L-PRx and PR (R = 0.475, p < 0.01), but not between PRx and PR. A correlation was found between age and PRx (R = 0.482, p = 0.01). No association with outcome for any of the indices was found. PRx/L-PRx and L-PRx/PR were moderately correlated with each other. Age was associated with PRx. None of the indices correlated with outcome when our ICP treatment regime was applied. Part of our null hypothesis, that the three indices are associated with outcome, must be rejected. There was, however, an association between some of the indices. To further understand the relation of treatment regimes and pressure reactivity indices, a larger, randomized study is warranted.

Classification and Characterization of Traumatic Brain Injuries in the Northern Region of Sweden

BACKGROUND

Traumatic brain injury (TBI) is a common cause of death and disability, the incidence of which in northern Sweden is not fully investigated. This study classifies and characterize epidemiological and demographic features of TBIs in a defined population in Umeå county, Sweden. Specifically, to evaluate frequencies of (1) intracranial lesions detected with computed tomography (CT), (2) need for emergency intervention, and (3) hospital admission, in minimal, mild, moderate, and severe TBI, respectively.

METHODS

The data were gathered from 4057 TBI patients visiting our emergency room (ER) during a two-year period (2015-2016), of whom 56% were men and approximately 95% had minimal TBIs (Glasgow Coma Scale (GCS), score 15).

RESULTS

Of all injuries, 97.8% were mild (GCS 14-15), 1.7% were moderate (GCS 9-13), and 0.5% were severe (GCS < 9). CT scans were performed on 46% of the patients, with 28% being hospitalized. A high annual TBI incidence of 1350 cases per 100,000 citizens was found. The mortality rate was 0.5% with the majority as expected in the elderly group (>80 years).

CONCLUSIONS

Minimal TBIs were not as mild as previously reported, with a relatively high frequency of abnormal CT findings and a high mortality rate. No emergency intervention was required in patients in the GCS 13-15 group with normal CT scans. These findings have implications for clinical practice in the ER with the suggestion to include biomarkers to reduce unnecessary CT scans.

Association of Early Beta-Blocker Exposure and Functional Outcomes in Critically Ill Patients With Moderate to Severe Traumatic Brain Injury: A Transforming Clinical Research and Knowledge in Traumatic Brain Injury Study

OBJECTIVES

We aimed to 1) describe patterns of beta-blocker utilization among critically ill patients following moderate-severe traumatic brain injury (TBI) and 2) examine the association of early beta-blocker exposure with functional and clinical outcomes following injury.

DESIGN

Retrospective cohort study.

SETTING

ICUs at 18 level I, U.S. trauma centers in the Transforming Clinical Research and Knowledge in TBI (TRACK-TBI) study.

PATIENTS

Greater than or equal to 17 years enrolled in the TRACK-TBI study with moderate-severe TBI (Glasgow Coma Scale of <13) were admitted to the ICU after a blunt TBI.

INTERVENTIONS

None.

MEASUREMENTS

Primary exposure was a beta blocker during the first 7 days in the ICU, with a primary outcome of 6-month Glasgow Outcome Scale-Extended (GOSE). Secondary outcomes included: length of hospital stay, in-hospital mortality, 6-month and 12-month mortality, 12-month GOSE score, and 6-month and 12-month measures of disability, well-being, quality of life, and life satisfaction.

MAIN RESULTS

Of the 450 eligible participants, 57 (13%) received early beta blockers (BB+ group). The BB+ group was on average older, more likely to be on a preinjury beta blocker, and more likely to have a history of hypertension. In the BB+ group, 34 participants (60%) received metoprolol only, 19 participants (33%) received propranolol only, 3 participants (5%) received both, and 1 participant (2%) received atenolol only. In multivariable regression, there was no difference in the odds of a higher GOSE score at 6 months between the BB+ group and BB- group (odds ratio = 0.86; 95% CI, 0.48-1.53). There was no association between BB exposure and secondary outcomes.

CONCLUSIONS

About one-sixth of subjects in our study received early beta blockers, and within this group, dose, and timing of beta-blocker administration varied substantially. No significant differences in GOSE score at 6 months were demonstrated, although our ability to draw conclusions is limited by overall low total doses administered compared with prior studies.

Low Morbidity and Mortality in Children with Severe Traumatic Brain Injury Treated According to the Lund Concept: A Population-Based Study

Previous reports of mortality and morbidity in pediatric severe traumatic brain injury (TBI) vary considerably, with few population-based studies. Mortality rates from 3-33 % and varying morbidity have been reported, most commonly using the Extended Glasgow Outcome Scale (eGOS). The Lund concept is a treatment algorithm for severe TBI aiming at controlling intracranial pressure (ICP) by reducing cerebral perfusion pressure (CPP). The aim of the present study was to retrospectively assess mortality and morbidity in a population of pediatric TBI treated according to the Lund concept. All cases of severe pediatric TBI (age <18 years) in the southern region of Sweden during 19 years were identified. Patients were treated according to the Lund concept. Mortality, eGOS, ICP, CPP, time in the neurosurgical intensive care unit (NICU), drugs delivered and surgical procedures were recorded. Data were analyzed both by dichotomized outcomes and by ordinal statistics. A total of 135 cases of severe TBI <18 years of age were recorded (incidence 2.0/100000) and 86 patients were admitted to the tertiary NICU. Mortality including all cases was 43% (mortality rate 0.7/100,000) and in NICU 10%. Outcome was good in 60%, moderate in 25%, unfavorable in 15%, with none in a vegetative status. In both dichotomized and ordinal analyses, CPP <40 mm Hg and ICP >15 were associated with poor outcome, supporting current guidelines. However, high CPP also was associated with increased mortality and morbidity, supporting that elevated CPP might increase cerebral edema. In this study, the Lund concept resulted in low mortality and a favorable outcome in a majority of severe pediatric TBI patients; however, randomized controlled trials are warranted to verify this.

Probabilistic prediction of increased intracranial pressure in patients with severe traumatic brain injury

Traumatic brain injury (TBI) causes alteration in brain functions. Generally, at intensive care units (ICU), intracranial pressure (ICP) is monitored and treated to avoid increases in ICP with associated poor clinical outcome. The aim was to develop a model which could predict future ICP levels of individual patients in the ICU, to warn treating clinicians before secondary injuries occur. A simple and explainable, probabilistic Markov model was developed for the prediction task ICP ≥ 20 mmHg. Predictions were made for 10-min intervals during 60 min, based on preceding hour of ICP. A prediction enhancement method was developed to compensate for data imbalance. The model was evaluated on 29 patients with severe TBI. With random data selection from all patients (80/20% training/testing) the specificity of the model was high (0.94–0.95) and the sensitivity good to high (0.73–0.87). Performance was similar (0.90–0.95 and 0.73–0.89 respectively) when the leave-one-out cross-validation was applied. The new model could predict increased levels of ICP in a reliable manner and the enhancement method further improved the predictions. Further advantages are the straightforward expandability of the model, enabling inclusion of other time series data and/or static parameters. Next step is evaluation on more patients and inclusion of parameters other than ICP.

Use of Hyperoncotic Human Albumin Solution in Severe Traumatic Brain Injury Revisited-A Narrative Review and Meta-Analysis

A significant proportion of patients with a severe traumatic brain injury (TBI) have hypoalbuminemia and require fluid resuscitation. Intravenous fluids can have both favorable and unfavorable consequences because of the risk of hyperhydration and hypo- or hyperosmolar conditions, which may affect the outcome of a TBI. Fluid resuscitation with human albumin solution (HAS) corrects low serum albumin levels and aids in preserving euvolemia in non-brain-injured intensive care units and in perioperative patients. However, the use of HAS for TBI remains controversial. In patients with TBI, the infusion of hypooncotic (4%) HAS was associated with adverse outcomes. The side effects of 4% HAS and the safety and efficacy of hyperoncotic (20-25%) HAS used in the Lund concept of TBI treatment need further investigation. A nonsystematic review, including a meta-analysis of controlled clinical trials, was performed to evaluate hyperoncotic HAS in TBI treatment. For the meta-analysis, the MEDLINE and EMBASE Library databases, as well as journal contents and reference lists, were searched for pertinent articles up to March 2021. Four controlled clinical studies involving 320 patients were included. The first was a randomized trial. Among 165 patients treated with hyperoncotic HAS, according to the Lund concept, 24 (14.5%) died vs. 59 out of 155 control patients (38.1%). A Lund concept intervention using hyperoncotic HAS was associated with a significantly reduced mortality (p = 0.002). Evidence of the beneficial effects of fluid management with hyperoncotic HAS on mortality in patients with TBI is at a high risk of bias. Prospective randomized controlled trials are required, which could lead to changes in clinical practice recommendations for fluid management in patients with TBI.

Correlation of Cerebral and Subcutaneous Glycerol in Severe Traumatic Brain Injury and Association with Tissue Damage

Background

This study is a substudy of a prospective consecutive double-blinded randomized study on the effect of prostacyclin in severe traumatic brain injury (sTBI). The aims of the present study were to investigate whether there was a correlation between brain and subcutaneous glycerol levels and whether the ratio of interstitial glycerol in the brain and subcutaneous tissue (glycerol_brain/sc) was associated with tissue damage in the brain, measured by using the Rotterdam score, S-100B, neuron-specific enolase (NSE), the Injury Severity Score (ISS), the Acute Physiology and Chronic Health Evaluation Score (APACHE II), and trauma type. A potential association with clinical outcome was explored.

Methods

Patients with sTBI aged 15–70 years presenting with a Glasgow Coma Scale Score ≤ 8 were included. Brain and subcutaneous adipose tissue glycerol levels were measured through microdialysis in 48 patients, of whom 42 had complete data for analysis. Brain tissue damage was also evaluated by using the Rotterdam classification of brain computed tomography scans and the biochemical biomarkers S-100B and NSE.

Results

In 60% of the patients, a positive relationship in glycerol_brain/sc was observed. Patients with a positive correlation of glycerol_brain/sc had slightly higher brain glycerol levels compared with the group with a negative correlation. There was no significant association between the computed tomography Rotterdam score and glycerol_brain/sc. S-100B and NSE were associated with the profile of glycerol_brain/sc. Our results cannot be explained by the general severity of the trauma as measured by using the Injury Severity Score or Acute Physiology and Chronic Health Evaluation Score.

Conclusions

We have shown that peripheral glycerol may flux into the brain. This effect is associated with worse brain tissue damage. This flux complicates the interpretation of brain interstitial glycerol levels. We remind the clinicians that a damaged blood–brain barrier, as seen in sTBI, may alter the concentrations of various substances, including glycerol in the brain. Awareness of this is important in the interpretation of the data bedside as well in research.

β-Blockers for traumatic brain injury: A systematic review and meta-analysis

BACKGROUND

Paroxysmal sympathetic hyperactivity (PSH) and catecholamine surge, which are associated with poor outcome, may be triggered by traumatic brain injury (TBI).β Adrenergic receptor blockers (β-blockers), as potential therapeutic agents to prevent paroxysmal sympathetic hyperactivity and catecholamine surge, have been shown to improve survival after TBI. The principal aim of this study was to investigate the effect of β-blockers on outcomes in patients with TBI.

METHODS

For this systematic review and meta-analysis, we searched MEDLINE, EMBASE, and Cochrane Library databases from inception to September 25, 2020, for randomized controlled trials, nonrandomized controlled trials, and observational studies reporting the effect of β-blockers on the following outcomes after TBI: mortality, functional measures, and cardiopulmonary adverse effects of β-blockers (e.g., hypotension, bradycardia, and bronchospasm). With use of random-effects model, we calculated pooled estimates, confidence intervals (CIs), and odds ratios (ORs) of all outcomes.

RESULTS

Fifteen studies with 12,721 patients were included. Exposure to β-blockers after TBI was associated with a significant reduction in adjusted in-hospital mortality (OR, 0.39; 95% CI, 0.30-0.51; I2 = 66.3%; p < 0.001). β-Blockers significantly improved the long-term (≥6 months) functional outcome (OR, 1.75; 95% CI, 1.09-2.80; I2 = 0%; p = 0.02). Statistically significant difference was not seen for cardiopulmonary adverse events (OR, 0.91; 95% CI, 0.55-1.50; I2 = 25.9%; p = 0.702).

CONCLUSION

This meta-analysis demonstrated that administration of β-blockers after TBI was safe and effective. Administration of β-blockers may therefore be suggested in the TBI care. However, more high-quality trials are needed to investigate the use of β-blockers in the management of TBI.

LEVEL OF EVIDENCE

Systematic review and meta-analysis, level III.

Positive fluid balance is associated with death and severity of brain injury in neonates with hypoxic-ischemic encephalopathy

OBJECTIVE

To investigate the association between fluid balance during therapeutic hypothermia (TH) and severity of brain injury on magnetic resonance imaging (MRI) in neonates with hypoxic-ischemic encephalopathy (HIE).

STUDY DESIGN

This is a secondary analysis of data from a prospective observational study in neonates with HIE. Daily net positive fluid balance during TH was investigated for association with the adverse primary outcome of death or moderate-to-severe brain injury on MRI using multivariable logistic regression.

RESULTS

Of the 150 neonates included, 50 suffered adverse outcome and had significantly higher net positive fluid balance (53 vs. 19 ml/kg/day, p < 0.01) during first 24 hours of TH. Neonates with a net positive fluid balance (>25 ml/kg/day) at 24 hours of TH had 3.4 (95% CI 1.3-9) times higher odds of adverse outcome.

CONCLUSIONS

Positive fluid balance during TH in neonates with HIE is independently associated with death or moderate-to-severe brain injury on MRI.

Mitigating the stress response to improve outcomes for older patients undergoing emergency surgery with the addition of beta-adrenergic blockade

As population age, healthcare systems and providers are likely to experience a substantial increase in the proportion of elderly patients requiring emergency surgery. Emergency surgery, compared with planned surgery, is strongly associated with increased risks of adverse postoperative outcomes due to the short time available for diagnosis, optimization, and intervention in patients presenting with physiological derangement. These patient populations, who are often frail and burdened with a variety of co-morbidities, have lower reserves to deal with the stress of the acute condition and the required emergency surgical intervention. In this review article, we discuss topical areas where mitigation of the physiological stress posed by the acute condition and asociated surgical intervention may be feasible. We consider the impact of the adrenergic response and use of beta blockers for these high-risk patients and discuss common risk factors such as frailty and delirium. A proactive multidisciplinary approach to peri-operative care aimed at mitigation of the stress response and proactive management of common conditions in the older emergency surgical patient could yield more favorable outcomes.

Efficacy and Safety of Wendan Decoction for Acute Brain Injury: A Randomized Controlled Study

Objectives: Despite the remarkable advances in critical care management of acute brain injury for the past 20 years, the prognoses remain poor. However, numerous reports indicate the efficacy of Traditional Chinese Medicine (TCM) therapy in stroke rehabilitation. This study aimed to determine the efficacy and safety of integrated TCM (Wendan decoction [WDD]) in patients with acute brain injury as a combination therapy in the early stages. Design: Prospective randomized controlled trial. Setting: Single-center study. Subjects: Sixty patients diagnosed with acute brain injury were randomly assigned to intervention and control groups, equally, and 41 patients completed the study. Interventions: All patients were treated by conventional neurologic intensive care. The 23 patients in the intervention group were administered with an integrated WDD in the early stages three times daily; combination treatment was initiated within 14 days and lasted >1 month. Outcome measures: Duration of ventilator use, intensive care unit stays, Glasgow Coma Scale (GCS) scores, motor response, the best muscle power, disability rating scale (DRS) scores, modified Rankin scale (mRS) scores, and the mortality rate for the first month. The other outcome measures were GCS scores, motor response, the best muscle power, DRS, mRS, and Barthel index (BI) scores 6 months later. Results: There was no mortality in the intervention group, but the rate was 39% in the control group for first month. Comparisons between groups showed significant differences (p < 0.05) in GCS, DRS, mRS, and BI scores, indicating improvements in the intervention group after 6 months. Conclusions: In the early stages of acute brain injury, combination treatment with WDD was found to be safe. Furthermore, this treatment may improve neurologic functional outcomes after 6 months.

Antisecretory Factor May Reduce ICP in Severe TBI-A Case Series

Traumatic brain injury (TBI) constitutes a global epidemic. Overall outcome is poor, with mortality ranging from 10 to 70% and significant long-term morbidity. Several experimental reports have claimed effect on traumatic edema, but all clinical trials have failed. Antisecretory factor, an endogenous protein, is commercially available as Salovum®, which is classified as a medical food by the European Union and has been proven effective in experimental trauma models. It has, however, previously not been tested in humans with severe TBI. We hereby report a case series of five adult patients with severe TBI, treated with Salovum. The objective of the intervention was to evaluate safety and, if possible, its effect on intracranial pressure and outcome. Patients received 1 g Salovum per kilo of body weight divided into six doses per 24 h. Each dose was administered through the nasogastric tube. Patients were scheduled for 5 days of treatment with Salovum. Intracranial pressure was controlled in all patients. In three of five patients, intracranial pressure could be controlled with Salovum and deep sedation (no barbiturates), except during periods of gastroparesis. Five of five patients had a favorable short-term outcome, and four of five patients had a favorable long-term outcome. No toxicity was observed. We conclude that at least three of the five treated patients experienced an effect of Salovum with signs of reduction of intracranial pressure and signs of clinical benefit. In order to validate the potential of antisecretory factor in TBI, a prospective, randomized, double-blind, placebo-controlled trial with Salovum has been initiated. Primary outcome for the trial is 30-day mortality; secondary outcomes are treatment intensity level, intracranial pressure, and number of days at the neurointensive care unit.

Beta-Blocker Therapy in Severe Traumatic Brain Injury: A Prospective Randomized Controlled Trial

Background

Observational studies have demonstrated improved outcomes in TBI patients receiving in-hospital beta-blockers. The aim of this study is to conduct a randomized controlled trial examining the effect of beta-blockers on outcomes in TBI patients.

Methods

Adult patients with severe TBI (intracranial AIS ≥ 3) were included in the study. Hemodynamically stable patients at 24 h after injury were randomized to receive either 20 mg propranolol orally every 12 h up to 10 days or until discharge (BB+) or no propranolol (BB−). Outcomes of interest were in-hospital mortality and Glasgow Outcome Scale-Extended (GOS-E) score on discharge and at 6-month follow-up. Subgroup analysis including only isolated severe TBI (intracranial AIS ≥ 3 with extracranial AIS ≤ 2) was carried out. Poisson regression models were used.

Results

Two hundred nineteen randomized patients of whom 45% received BB were analyzed. There were no significant demographic or clinical differences between BB+ and BB− cohorts. No significant difference in in-hospital mortality (adj. IRR 0.6 [95% CI 0.3–1.4], p = 0.2) or long-term functional outcome was measured between the cohorts (p = 0.3). One hundred fifty-four patients suffered isolated severe TBI of whom 44% received BB. The BB+ group had significantly lower mortality relative to the BB− group (18.6% vs. 4.4%, p = 0.012). On regression analysis, propranolol had a significant protective effect on in-hospital mortality (adj. IRR 0.32, p = 0.04) and functional outcome at 6-month follow-up (GOS-E ≥ 5 adj. IRR 1.2, p = 0.02).

Conclusion

Propranolol decreases in-hospital mortality and improves long-term functional outcome in isolated severe TBI. This randomized trial speaks in favor of routine administration of beta-blocker therapy as part of a standardized neurointensive care protocol.

Level of evidence

Level II; therapeutic.

Study type

Therapeutic study.

Resuscitation Strategies for Traumatic Brain Injury

PURPOSE OF REVIEW

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality; however, little definitive evidence exists about most clinical management strategies. Here, we highlight important differences between two major guidelines, the 2016 Brain Trauma Foundation guidelines and the Lund Concept, along with recent pre-clinical and clinical data.

RECENT FINDINGS

While intracranial pressure (ICP) monitoring has been questioned, the majority of literature demonstrates benefit in severe TBI. The optimal cerebral perfusion pressure (CPP) and ICP are yet unknown, but likely as important is the concept of ICP burden. The evidence for anti-hypertensive therapy is strengthening. Decompressive craniectomy improves mortality, but at the cost of increased morbidity. Plasma-based resuscitation has demonstrated benefit in multiple pre-clinical TBI studies.

SUMMARY

The management of hemodynamics and intravascular volume are crucial in TBI. Based on recent evidence, ICP monitoring, anti-hypertensive therapy, minimal use of vasopressors/inotropes, and plasma resuscitation may improve outcomes.

Beta-blockers and Traumatic Brain Injury: A Systematic Review, Meta-analysis, and Eastern Association for the Surgery of Trauma Guideline

OBJECTIVE

To determine if beta-(β)-blockers improve outcomes after acute traumatic brain injury (TBI).

BACKGROUND

There have been no new inpatient pharmacologic therapies to improve TBI outcomes in a half-century. Treatment of TBI patients with β-blockers offers a potentially beneficial approach.

METHODS

Using MEDLINE, EMBASE, and CENTRAL databases, eligible articles for our systematic review and meta-analysis (PROSPERO CRD42016048547) included adult (age ≥ 16 years) blunt trauma patients admitted with TBI. The exposure of interest was β-blocker administration initiated during the hospitalization. Outcomes were mortality, functional measures, quality of life, cardiopulmonary morbidity (e.g., hypotension, bradycardia, bronchospasm, and/or congestive heart failure). Data were analyzed using a random-effects model, and represented by pooled odds ratio (OR) with 95% confidence intervals (CI) and statistical heterogeneity (I).

RESULTS

Data were extracted from 9 included studies encompassing 2005 unique TBI patients with β-blocker treatment and 6240 unique controls. Exposure to β-blockers after TBI was associated with a reduction of in-hospital mortality (pooled OR 0.39, 95% CI: 0.27-0.56; I = 65%, P < 0.00001). None of the included studies examined functional outcome or quality of life measures, and cardiopulmonary adverse events were rarely reported. No clear evidence of reporting bias was identified.

CONCLUSIONS

In adults with acute TBI, observational studies reveal a significant mortality advantage with β-blockers; however, quality of evidence is very low. We conditionally recommend the use of in-hospital β-blockers. However, we recommend further high-quality trials to answer questions about the mechanisms of action, effectiveness on subgroups, dose-response, length of therapy, functional outcome, and quality of life after β-blocker use for TBI.

Critical Evaluation of the Lund Concept for Treatment of Severe Traumatic Head Injury, 25 Years after Its Introduction

When introduced in 1992, the Lund concept (LC) was the first complete guideline for treatment of severe traumatic brain injury (s-TBI). It was a theoretical approach, based mainly on general physiological principles-i.e., of brain volume control and optimization of brain perfusion and oxygenation of the penumbra zone. The concept gave relatively strict outlines for cerebral perfusion pressure, fluid therapy, ventilation, sedation, nutrition, the use of vasopressors, and osmotherapy. The LC strives for treatment of the pathophysiological mechanisms behind symptoms rather than just treating the symptoms. The treatment is standardized, with less need for individualization. Alternative guidelines published a few years later (e.g., the Brain Trauma Foundation guidelines and European guidelines) were mainly based on meta-analytic approaches from clinical outcome studies and to some extent from systematic reviews. When introduced, they differed extensively from the LC. We still lack any large randomized outcome study comparing the whole concept of BTF guidelines with other guidelines including the LC. From that point of view, there is limited clinical evidence favoring any of the s-TBI guidelines used today. In principle, the LC has not been changed since its introduction. Some components of the alternative guidelines have approached those in the LC. In this review, I discuss some important principles of brain hemodynamics that have been lodestars during formulation of the LC. Aspects of ventilation, nutrition, and temperature control are also discussed. I critically evaluate the most important components of the LC 25 years after its introduction, based on hemodynamic principles and on the results of own an others experimental and human studies that have been published since then.

Human jugular vein collapse in the upright posture: implications for postural intracranial pressure regulation

Background

Intracranial pressure (ICP) is directly related to cranial dural venous pressure (P_dural). In the upright posture, P_dural is affected by the collapse of the internal jugular veins (IJVs) but this regulation of the venous pressure has not been fully understood. A potential biomechanical description of this regulation involves a transmission of surrounding atmospheric pressure to the internal venous pressure of the collapsed IJVs. This can be accomplished if hydrostatic effects are cancelled by the viscous losses in these collapsed veins, resulting in specific IJV cross-sectional areas that can be predicted from flow velocity and vessel inclination.

Methods

We evaluated this potential mechanism in vivo by comparing predicted area to measured IJV area in healthy subjects. Seventeen healthy volunteers (age 45 ± 9 years) were examined using ultrasound to assess IJV area and flow velocity. Ultrasound measurements were performed in supine and sitting positions.

Results

IJV area was 94.5 mm² in supine and decreased to 6.5 ± 5.1 mm² in sitting position, which agreed with the predicted IJV area of 8.7 ± 5.2 mm² (equivalence limit ±5 mm², one-sided t tests, p = 0.03, 33 IJVs).

Conclusions

The agreement between predicted and measured IJV area in sitting supports the occurrence of a hydrostatic-viscous pressure balance in the IJVs, which would result in a constant pressure segment in these collapsed veins, corresponding to a zero transmural pressure. This balance could thus serve as the mechanism by which collapse of the IJVs regulates P_dural and consequently ICP in the upright posture.

Electronic supplementary material

The online version of this article (doi:10.1186/s12987-017-0065-2) contains supplementary material, which is available to authorized users.

A prospective outcome study observing patients with severe traumatic brain injury over 10-15 years

BACKGROUND

Severe traumatic brain injury (sTBI) can be divided into primary and secondary injuries. Intensive care protocols focus on preventing secondary injuries. This prospective cohort study was initiated to investigate outcome, including mortality, in patients treated according to the Lund Concept after a sTBI covering 10-15 years post-trauma.

METHODS

Patients were included during 2000-2004 when admitted to the neurointensive care unit, Sahlgrenska University Hospital. Inclusion criteria were: Glasgow coma scale score of ≤8, need for artificial ventilation and intracranial monitoring. Glasgow Outcome Scale (GOS) was used to evaluate outcome both at 1-year and 10-15 years post-trauma.

RESULTS

Ninety-five patients, (27 female and 68 male), were initially included. Both improvement and deterioration were noted between 1- and 10-15 years post-injury. Mortality rate (34/95) was higher in the studied population vs. a matched Swedish population, (Standard mortality rate (SMR) 9.5; P < 0.0001). When dividing the cohort into Good (GOS 4-5) and Poor (GOS 2-3) outcome at 1-year, only patients with Poor outcome had a higher mortality rate than the matched population (SMR 7.3; P < 0.0001). Further, good outcome (high GOS) at 1-year was associated with high GOS 10-15 years post-trauma (P < 0.0001). Finally, a majority of patients demonstrated symptoms of mental fatigue.

CONCLUSION

This indicates that patients with severe traumatic brain injury with Good outcome at 1-year have similar survival probability as a matched Swedish population and that high Glasgow outcome scale at 1-year is related to good long-term outcome. Our results further emphasise the advantage of the Lund concept.

APOE ε4 positive patients suffering severe traumatic head injury are more prone to undergo decompressive hemicraniectomy

OBJECT

In this paper we tested the hypothesis if patients with severe traumatic brain injury and presence of the apolipoprotein E (APOE) ε4 allele are more prone to undergo the surgical procedure decompressive hemicraniectomy (DC) in order to bring the intracranial pressure (ICP) under control.

METHODS

In this prospective consecutive study patients with sTBI were enrolled (n=48). Inclusion criteria were arrival to our level one trauma university hospital within 24h after trauma, patient age between 15 and 70years, Glasgow Coma Scale (GCS) score ≤8 at the time of intubation and sedation, an initial cerebral perfusion pressure >10mmHg. Venous blood was sampled for APOE genotype determination. Clinical outcome at 6months after injury was assessed with the Extended Glasgow Outcome Scale (GOSE). All surgical procedures needed for each patient were registered.

RESULTS

Patients with the APOE ε4 allele were significantly overrepresented in the DC group. In the APOE ε4+DC group, ICP_max and ICP_mean during the first 36h were significantly higher and GOSE was significantly worse at 6months.

CONCLUSION

Our data suggest that patients with the APOE ε4 allele are predisposed for the need of DC more often than patients without the APOE ε4 allele. Thus, it seems to be of importance to consider the APOE genotype in patients suffering severe traumatic brain injury in order to forecast the need for a more exquisite intensive care.

Neuropulmonology

Neuropulmonology refers to the complex interconnection between the central nervous system and the respiratory system. Neurologic injury includes traumatic brain injury, hemorrhage, stroke, and seizures, and in each there are far-reaching effects that can result in pulmonary dysfunction. Systemic changes can induce impairment of pulmonary function due to changes in the core structure and function of the lung. The conditions and disorders that often occur in these patients include aspiration pneumonia, neurogenic pulmonary edema, and acute respiratory distress syndrome, but also several abnormal respiratory patterns and sleep-disordered breathing. Lung infections, pulmonary edema - neurogenic or cardiogenic - and pulmonary embolus all are a serious barrier to recovery and can have significant effects on outcomes such as hospital course, prognosis, and mortality. This review presents the spectrum of pulmonary abnormalities seen in neurocritical care.

Effects of Intracranial Pressure Monitoring on Mortality in Patients with Severe Traumatic Brain Injury: A Meta-Analysis

BACKGROUND

The Brain Trauma Foundation (BTF) guidelines published in 2007 suggest some indications for intracranial pressure (ICP) monitoring in severe traumatic brain injury (TBI). However, some studies had not shown clinical benefit in patients with severe TBI; several studies had even reported that ICP monitoring was associated with an increased mortality rate. The effect of ICP monitoring has remained controversial, regardless of the ICP monitoring guidelines. Here we performed a meta-analysis of published studies to assess the effects of ICP monitoring in patients with severe TBI.

METHODS

We searched three comprehensive databases, the Cochrane Library, PUBMED, and EMBASE, for studies without limitations published up to September 2015. Mortality, ICU LOS, and hospital LOS were analyzed with Review Manager software according to data from the included studies.

RESULTS

Eighteen eligible studies involving 25229 patients with severe TBI were included in our meta-analysis. The results indicated no significant reduction in the ICP monitored group in mortality (hospitalized before 2007), hospital mortality (hospitalized before 2007), mortality in randomized controlled trials. However, overall mortality, mortality (hospitalized after 2007), hospital mortality (hospitalized after 2007), mortality in observational studies (hospitalized after 2007), 2-week mortality, 6-month mortality, were reduced in ICP monitored group. Patients with an increased ICP were more likely to require ICP monitoring.

CONCLUSION

Superior survival was observed in severe TBI patients with ICP monitoring since the third edition of "Guidelines for the Management of Severe Traumatic Brain Injury," which included "Indications for intracranial pressure monitoring," was published in 2007.

Alpha-2 agonists for sedation in mechanically ventilated neurocritical care patients: a systematic review protocol

BACKGROUND

Sedation is an important consideration in the care of the neurocritically ill patient. It provides anxiety and relief, facilitates procedures and nursing tasks, and minimizes intolerance of mechanical ventilation. Alpha-2 agonists such as dexmedetomidine and clonidine have been shown to be an effective alternative in the general critical care population by reducing duration of mechanical ventilation and length of stay in the intensive care unit (ICU), as compared to traditional sedative agents such as propofol or benzodiazepines. However, there is a paucity of literature detailing their utility and safety in neurocritical care, a population that presents unique considerations for management of global and cerebral hemodynamics, agitation, and facilitation of neurological assessments. The objective of this review is to assess the efficacy and safety of alpha-2 agonists for non-procedural sedation in mechanically ventilated brain-injured patients.

METHODS

We will search the Embase and MEDLINE databases for all randomized controlled trials, prospective and retrospective cohort studies examining neurocritically ill adult patients aged 18 years and older who are on mechanical ventilation and receiving alpha-2 agonists for non-procedural sedation. Primary outcomes of interest include effect on mean arterial pressure (MAP), intracranial pressure (ICP), and cerebral perfusion pressure (CPP). Secondary outcomes include adverse events, duration of mechanical ventilation, 30-day mortality, ICU length of stay, incidence of delirium, and quality of sedation. Continuous outcomes will be presented as means and mean differences and discrete counting events will be presented as event rates. Pre-defined criteria for heterogeneity are provided for determination of pooling eligibility. Where appropriate, we will pool estimates for individual outcomes. Planned subgroup analyses include specific alpha-2 agonist agent, study design, clinical diagnosis, dosing regimen, and use of adjunctive agents. Quality of evidence for the recommendation will be assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach where appropriate.

DISCUSSION

This systematic review will summarize the evidence on the efficacy and safety for the use of alpha-2 agonists as sedative agents in the neurocritical care population.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016037045.

A clinical scale to communicate surgical urgency for traumatic brain injury: A preliminary study

BACKGROUND

While the Glasgow Coma Scale (GCS) provides a tool for evaluating traumatic brain injury (TBI) patients, there is no widely used scale that provides guidance for surgical management. This study introduces a scoring system that physicians potentially could use to determine and communicate the need for surgical decompression in TBI patients. The proposed system is designed to be both comprehensive and easy to use.

METHODS

The Surgical Intervention for Traumatic Injury (SITI) scale uses radiographic and clinical findings. Patients were graded based on their GCS: GCS >12 received 0 points, GCS 9-12 received 1 point, and GCS <9 received 2 points. An enlarged unilateral pupil added 2 points. Computed tomography findings were also graded: midline shift <5 mm received 0 points, 5-10 mm received 2 points, and >10 mm received 4 points. The presence of temporal pathology added 1 point, and epidural hematoma (EDH) ≥10 mm added 2 points. Retrospective analysis of 48 patients was then performed using the SITI scale.

RESULTS

Of the 48 patients reviewed, 24 patients underwent craniotomy and the other 24 were treated non-operatively. The mean SITI score was 5.7 (range 3-10) for operative patients and 2.5 (range 1-4) for non-operative patients.

CONCLUSIONS

The proposed SITI scale is designed to be a simple, objective system for assisting in communication between clinical services and for suggesting the need for surgical decompression for TBI. Based upon our initial review, a SITI score of 3 or less correlated with non-operative management and a score of 5 or greater correlated with operative management. Given the results of this study, we believe that further development and research of the SITI scale are warranted.