Brief episodes of intracranial hypertension and cerebral hypoperfusion are associated with poor functional outcome after severe traumatic brain injury

Isotonic balanced fluid versus 0.9% saline in patients with moderate to severe traumatic brain injury: A double-blinded randomised controlled trial

BACKGROUND AND IMPORTANCE

Traumatic brain injury (TBI) is a global health concern with significant economic impact. Optimal fluid therapy aims to restore intravascular volume, maintain cerebral perfusion pressure and blood flow, thus preventing secondary brain injury. While 0.9% saline (NS) is commonly used, concerns about acid-base and electrolyte imbalance and development of acute kidney injury (AKI) lead to consideration of balanced fluids as an alternative.

OBJECTIVES

This study aimed to compare the outcomes of patients with moderate to severe TBI treated with Sterofundin (SF) versus NS.

DESIGN, SETTINGS AND PARTICIPANTS

A double-blinded randomised controlled trial of patients aged 18 to 65 years with TBI was conducted at the University Malaya Medical Centre from February 2017 to November 2019.

INTERVENTION OR EXPOSURE

Patients were randomly assigned to receive either NS or SF. The study fluids were administered for 72 h as continuous infusions or boluses. Participants, investigators, and staff were blinded to the fluid type.

OUTCOMES MEASURE AND ANALYSIS

The primary outcome was in-hospital mortality. Relative risk (RR) with 95% confidence interval (CI) was calculated.

MAIN RESULTS

A total of 70 patients were included in the analysis, with 38 in the NS group and 32 in the SF group. The in-hospital mortality rate were 3 (7.9%) in the NS group vs. 4 (12.5%) in the SF group, RR = 1.29 (95% CI, 0.64 to 2.59; p = 0.695). No patients developed AKI and required renal replacement therapy. ICP on day 3 was significantly higher in the SF group (18.60 ± 9.26) compared to 12.77 ± 3.63 in the NS group, (95% CI, -11.46 to 0.20; p = 0.037). There were no significant differences in 3-day biochemical parameters and cerebral perfusion pressure, ventilator-free days, length of ICU stay, or Glasgow Outcome Scale-Extended (GOS-E) score at 6 months.

CONCLUSIONS

In patients with moderate to severe TBI, the use of SF was not associated with reduced in-hospital mortality, development of AKI, or improved 6-month GOS-E when compared to NS.

Intracranial Pressure Monitoring and Treatment Thresholds in Acute Neural Injury: A Narrative Review of the Historical Achievements, Current State, and Future Perspectives

Since its introduction in the 1960s, intracranial pressure (ICP) monitoring has become an indispensable tool in neurocritical care practice and a key component of the management of moderate/severe traumatic brain injury (TBI). The primary utility of ICP monitoring is to guide therapeutic interventions aimed at maintaining physiological ICP and preventing intracranial hypertension. The rationale for such ICP maintenance is to prevent secondary brain injury arising from brain herniation and inadequate cerebral blood flow. There exists a large body of evidence indicating that elevated ICP is associated with mortality and that aggressive ICP control protocols improve outcomes in severe TBI patients. Therefore, current management guidelines recommend a cerebral perfusion pressure (CPP) target range of 60-70 mm Hg and an ICP threshold of >20 or >22 mm Hg, beyond which therapeutic intervention should be initiated. Though our ability to achieve these thresholds has drastically improved over the past decades, there has been little to no change in the mortality and morbidity associated with moderate-severe TBI. This is a result of the "one treatment fits all" dogma of current guideline-based care that fails to take individual phenotype into account. The way forward in moderate-severe TBI care is through the development of continuously derived individualized ICP thresholds. This narrative review covers the topic of ICP monitoring in TBI care, including historical context/achievements, current monitoring technologies and indications, treatment methods, associations with patient outcome and multi-modal cerebral physiology, present controversies surrounding treatment thresholds, and future perspectives on personalized approaches to ICP-directed therapy.

Development of Traumatic Brain Injury Associated Intracranial Hypertension Prediction Algorithms: A Narrative Review

Traumatic intracranial hypertension (tIH) is a common and potentially lethal complication of moderate to severe traumatic brain injury (m-sTBI). It often develops with little warning and is managed reactively with the tiered application of intracranial pressure (ICP)-lowering interventions administered in response to an ICP rising above a set threshold. For over 45 years, a variety of research groups have worked toward the development of technology to allow for the preemptive management of tIH in the hope of improving patient outcomes. In 2022, the first operationalizable tIH prediction system became a reality. With such a system, ICP lowering interventions could be administered prior to the rise in ICP, thus protecting the patient from potentially damaging tIH episodes and limiting the overall ICP burden experienced. In this review, we discuss related approaches to ICP forecasting and IH prediction algorithms, which collectively provide the foundation for the successful development of an operational tIH prediction system. We also discuss operationalization and the statistical assessment of tIH algorithms. This review will be of relevance to clinicians and researchers interested in development of this technology as well as those with a general interest in the bedside application of machine learning (ML) technology.

Troponin I New Biomarker in Traumatic Brain Injury

Mortality in traumatic brain injury (TBI) is thought to be pathology in the heart-brain axis but its effect on the prognosis of traumatic brain injury remains unclear. Our study aimed to investigate the relationship between cardiac troponin I (cTnI) level and prognosis in TBI patients. Between January 2017 and May 2021, 480 patients diagnosed with TBI, who applied to the emergency department, were retrospectively included in this multicentric study. The databases of the hospitals were examined comprehensively and the demographic, clinical, laboratory, radiological, and therapeutic data and results of the patients were obtained. The severity of trauma and clinical status was evaluated with AIS, Injury Severity Score (ISS), ASA physical status, and Glasgow Coma Scale (GCS). The severity of the trauma was evaluated with the ISS. The modified Rankin Scale (mRS) and the Glasgow Outcome Scale (GOS) at discharge were used to evaluate in-hospital clinical outcomes. cTnI levels were classified into three categories: normal (< 0.05 ng/ml), mildly elevated (0.05–0.99 ng/ml), and severely elevated (≥ 1 ng/ml). The mean age of the patients was 41.7 and 75.4% of them were men. It was observed that mortality among patients over 65 years (13.9%) increased. High cTnI was detected in 284 (59.1%) patients. Although it was not statistically significant regarding the elevation of cTnI in patients under 65 years of age (P = 0.62), the difference was significant for cTnI in patients over 65 years of age (P < 0.001). The relationship between cTnI elevation was found to be statistically significant (P < 0.001) as the severity of the trauma increased and when severe additional traumas (thoracic, abdominal, or pelvic) occurred. A high cTnI level is associated with poor prognosis in TBI patients. cTnI measurement is a useful tool for early risk stratification and accelerated care; however, further prospective studies are needed.

Neutrophil-lymphocyte ratio as a predictor of outcome following traumatic brain injury: Systematic review and meta-analysis

Objectives

The neutrophil-to-lymphocyte ratio (NLR) is a simple and routinely performed hematological parameter; however, studies on NLR as a prognostic tool in traumatic brain injury (TBI) have yielded contradictory results.

Materials and Methods

This systematic review and meta-analysis was conducted according to the Preferred Reporting Items in the Systematic Review and Meta-Analysis guidelines 2020. Electronic databases of PubMed, Cochrane Library, Web of Science, and Scopus were searched. The population consisted of TBI patients in the absence of moderate and severe extracranial injury. Day 1 NLR was taken for the analysis. The outcomes evaluated were mortality and the Glasgow Outcome Scale (GOS). No restrictions were placed on the language, year and country of publication, and duration of follow-up. Animal studies were excluded from the study. Studies, where inadequate data were reported for the outcomes, were included in the qualitative synthesis but excluded from the quantitative synthesis. Study quality was evaluated using the Newcastle-Ottawa scale (NOS). The risk of bias was estimated using the Cochrane RoBANS risk of bias tool.

Results

We retrieved 7213 citations using the search strategy and 2097 citations were excluded based on the screening of the title and abstract. Full text was retrieved for 40 articles and subjected to the eligibility criteria, of which 28 were excluded from the study. Twelve studies were eligible for the synthesis of the systematic review while seven studies qualified for the meta-analysis. The median score of the articles was 8/9 as per NOS. The risk of selection bias was low in all the studies while the risk of detection bias was high in all except one study. Ten studies were conducted on adult patients, while two studies reported pediatric TBI. A meta-analysis for GOS showed that high NLR predicted unfavorable outcomes at ≥6 months with a mean difference of -5.18 (95% confidence interval: -10.04, -0.32); P = 0.04; heterogeneity (I2), being 98%. The effect estimates for NLR and mortality were a mean difference of -3.22 (95% confidence interval: -7.12, 0.68), P = 0.11, and an I2 of 85%. Meta-analysis for Area under the curve (AUC) receiver operating characteristic of the included studies showed good predictive power of NLR in predicting outcomes following TBI with AUC 0.706 (95% CI: 0.582-0.829).

Conclusion

A higher admission NLR predicts an increased mortality risk and unfavorable outcomes following TBI. However, future research will likely address the existing gaps.

Dynamics of neutrophil-to-lymphocyte ratio can be associated with clinical outcomes of children with moderate to severe traumatic brain injury: A retrospective observational study

BACKGROUND

The neutrophil to lymphocyte ratio (NLR) has been reported to be associated with clinical outcomes of patients with severe traumatic brain injury (TBI). This study aimed to evaluate the correlation between the dynamics of NLR and clinical outcomes of pediatric patients with moderate to severe TBI.

METHODS

We retrospectively evaluated the clinical data of a total of 374 pediatric patients with moder-ate to severe TBI who were treated in our department between May 2016 and May 2020. Clinical and laboratory data including the NLR upon admission and the NLR on hospital day four were collected. Poor clinical outcome was defined as Glasgow Outcome Scale (GOS) of 1-3. Multivariable logistic regression analyses were performed to investigate the correlation between the dynamics of NLR and clinical outcome.

RESULTS

Three hundred seventy-four pediatric patients (mean age 7.37 ± 3.11, 52.7% male) were evaluated. Based on the ROC curves, a value of 5 was determined as the NLR cut-off value. The corresponding cutoff value for delta NLR was 1. The Glasgow Coma Scale (GCS) (OR, 3.42; 95% CI: 1.88-5.28; P <0.001), the light reflex (OR, 1.79; 95% CI: 1.34- 2.84; P = 0.027), the Rotterdam CT score (OR, 2.71; 95% CI: 1.72-4.13; P = 0.021), and delta NLR (OR, 1.71; 95% CI: 1.13- 2.52; P = 0.034) were identified as independent predictors for unfavorable outcomes in multivariable logistic regression analysis.

CONCLUSIONS

The result of the present study suggest that delta NLR could be a predictor of poor clinical outcome of pediatrics with moderate to severe TBI. This cost-effective and easily available biomarker could be used to predict clinical outcomes in these patients.

Elevated Serum Complement C1q Levels After Traumatic Brain Injury and Its Association with Poor Prognosis

OBJECTIVE

Complement C1q is implicated in neuroinflammation. We intended to discern the relationship between serum C1q levels and severity in addition to prognosis following traumatic brain injury (TBI).

METHODS

In this prospective, observational study, serum C1q levels were quantified in 188 TBI patients and 188 healthy controls. Glasgow coma scale (GCS) and Rotterdam computed tomography (CT) classification were used as clinical and radiological indicators of severity. Patients with extended Glasgow outcome scale (GOSE) score of 1-4 at 6 months after trauma were considered to have a poor outcome. Multiple logistic regression model was built to ascertain the independent association of serum C1q levels with 6-month poor outcome. Receiver operating characteristic (ROC) curve was configured for analysis of prognostic capability with respect to serum C1q levels.

RESULTS

TBI patients exhibited substantially higher serum C1q levels than controls (median, 223.9 mg/l versus 75.4 mg/l). Serum C1q levels of patients were tightly correlated with GCS score (r = -0.671), Rotterdam CT classification (r = 0.604) and GOSE score (r = -0.581). An area under the ROC curve was yielded of 0.793 (95% confidence interval = 0.728-0.849), and serum C1q levels above 345.5 mg/l discriminated the risk of 6-month poor outcome with 59.6% sensitivity and 92.6% specificity. Serum C1q levels above 345.5 mg/l retained as an independent predictor for 6-month poor outcome with odds ratio of 4.922 (95% confidence interval = 1.552-15.606; P = 0.017).

CONCLUSION

Elevated serum C1q levels are closely correlated with traumatic severity and independently predicted the risk of long-term poor prognosis after TBI.

Utility of Serum Growth Arrest-Specific Protein 6 as a Biomarker of Severity and Prognosis After Severe Traumatic Brain Injury: A Prospective Observational Study

OBJECTIVE

Growth arrest-specific protein 6 (Gas6) may harbor protective effects in acute brain injury. This study was designed to determine the relation of serum Gas6 levels to severity and prognosis after traumatic brain injury (TBI).

METHODS

In this prospective cohort study of 114 controls and 114 patients with severe TBI, multivariate analysis was used to assess relationships between serum Gas6 levels, Glasgow coma scale (GCS) score, Rotterdam computed tomography (CT) score, postinjury 180-day mortality, overall survival and poor prognosis (Extended Glasgow outcome scale score 1-4).

RESULTS

Significantly increased serum Gas6 levels of patients (median, 10.3 ng/mL versus 32.5 ng/mL; P < 0.001), as compared with controls, were independently correlated with Rotterdam CT score (t = 3.629, P < 0.001) and GCS score (t=-3.393, P = 0.001), and independently predicted 180-day mortality (odds ratio, 1.078; 95% confidence interval (CI), 1.007-1.154), overall survival (hazard ratio, 1.074; 95% CI, 1.012-1.139) and poor prognosis (odds ratio, 1.129; 95% CI, 1.059-1.205). Areas under receiver operating characteristic curve (AUCs) of serum Gas6 levels for discriminating risks of 180-day mortality and poor prognosis were 0.785 (95% CI, 0.699-0.857) and 0.793 (95% CI, 0.707-0.863), respectively; and serum Gas6 levels above 30.9 ng/mL and 28.3 ng/mL predicted 180-day mortality and poor prognosis with maximum Youden indices of 0.451 and 0.468, respectively. The predictive ability of serum Gas6 levels for mortality was similar to those of GCS score (AUC, 0.833; 95% CI, 0.751-0.896; P = 0.286) and Rotterdam CT score (AUC, 0.823; 95% CI, 0.740-0.888; P = 0.432). The discriminatory capability of serum Gas6 levels for the risk of poor prognosis was in the range of GCS score (AUC, 0.846; 95% CI, 0.766-0.906; P = 0.178) and Rotterdam CT score (AUC, 0.831; 95% CI, 0.750-0.895; P = 0.368).

CONCLUSION

Serum Gas6 may appear as a promising biochemical parameter for aiding in the assessment of trauma severity and prediction of prognosis among patients with severe TBI.

Ultrasound measurement of the optic nerve sheath diameter in traumatic brain injury: a narrative review

Background : Raised intracranial pressure (ICP) needs to be investigated in various situations, especially in traumatic brain injury (TBI). Ultra-sonographic (US) measurement of the optic nerve sheath diameter (ONSD) is a promising noninvasive tool for assessing elevated ICP. Objectives : This narrative review aimed to explain the history of and indications forUS measurement of ONSD. We focused on the detection of elevated ICP after TBI and discussed the possible improvements in detection methods. Conclusions : US measurement of ONSD in TBI cases provides a qualitative but no quantitative assessment of ICP. Current studies usually calculate their own optimum cutoff value for detecting raised ICP based on the balance between sensitivity and specificity of the method when compared with invasive methods. There is no universally accepted threshold. We did not find any paper focusing on the prognosis of patients benefiting from it when compared with usual care. Another limitation is the lack of standardization. US measurement of ONSD cannot be used as the sole technique to detect elevated ICP and monitor its evolution, but it can be a useful tool in a multimodal protocol and it might help to determine the prognosis of patients in various situations.

Relationship of Optic Nerve Sheath Diameter and Intracranial Hypertension in Patients with Traumatic Brain Injury

Background

to study the association between optic nerve sheath diameter (ONSD) and intracranial pressure (ICP) in patients with moderate-to-severe brain injury.

Patients and Methods

A retrospective cohort study of traumatic brain injury (TBI) patients was conducted between 2010 and 2014. Data were analyzed and compared according to the ICP monitoring cutoff values. Outcomes included intracranial hypertension (ICH) and mortality.

Results

A total of 167 patients with a mean age of 33 ± 14 years, of them 96 had ICP monitored. ICP values correlated with ONSD measurement (r = 0.21, P = 0.04). Patients who developed ICH were more likely to have higher mean ONSD (P = 0.01) and subarachnoid hemorrhage (SAH) (P = 0.004). Receiver operating curve for ONSD showed a cutoff value of 5.6 mm to detect ICH with sensitivity 72.2% and specificity 50%. Age and ICP were independent predictors of inhospital mortality in multivariate model. Another model with same covariates showed ONSD and SAH to be independent predictors of ICH. Simple linear regression showed a significant association of ONSD with increased ICP (β = 0.21, 95% confidence interval 0.25-5.08, P = 0.03).

Conclusions

ONSD is a simple noninvasive measurement on initial CT in patients with TBI that could be a surrogate for ICP monitoring. However, further studies are warranted.

Association of optic nerve sheath diameter in ocular ultrasound with prognosis in patients presenting with acute stroke symptoms

Background

Measurement of optic nerve sheath diameter (ONSD) by means of ocular ultrasound (US), can diagnose elevated intracranial pressure (ICP). Stroke accompanied by elevated ICP might have a worse prognosis.

Objective

To determine the relationship of ONSD in ocular US with prognosis in acute stroke in the emergency department (ED).

Methods

Patients with acute presentations of stroke, presenting to the ED in 2017 (during six months), were enrolled in our study. US exam was performed on all of them and ONSD was determined in two longitudinal and transverse dimensions. Demographic data, rate of patients' admission in the ward or intensive care unit, one-month patients’ outcome and type of stroke were recorded. The relationship of mean ONSD was evaluated with study variables.

Results

In this study, 60 patients were enrolled. The mean ± SD ONSD in the deceased cases was 4.40 ± 0.64 mm and in the survived patients was 3.83 ± 0.56 mm. Youden index calculated ONSD>3.9 mm as the best cut-off point in mortality prognosis. It has a sensitivity of 83.3% and a specificity of 59.2%.

Conclusions

Increased ONSD had a direct relationship with mortality rate in acute stroke.

Intracranial pressure elevations in diffuse axonal injury: association with nonhemorrhagic MR lesions in central mesencephalic structures

OBJECTIVE

Increased intracranial pressure (ICP) in patients with severe traumatic brain injury (TBI) with diffuse axonal injury (DAI) is not well defined. This study investigated the occurrence of increased ICP and whether clinical factors and lesion localization on MRI were associated with increased ICP in patients with DAI.

METHODS

Fifty-two patients with severe TBI (median age 24 years, range 9-61 years), who had undergone ICP monitoring and had DAI on MRI, as determined using T2*-weighted gradient echo, susceptibility-weighted imaging, and diffusion-weighted imaging (DWI) sequences, were enrolled. The proportion of good monitoring time (GMT) with ICP > 20 mm Hg during the first 120 hours postinjury was calculated and associations with clinical and MRI-related factors were evaluated using linear regression.

RESULTS

All patients had episodes of ICP > 20 mm Hg. The mean proportion of GMT with ICP > 20 mm Hg was 5%, and 27% of the patients (14/52) spent more than 5% of GMT with ICP > 20 mm Hg. The Glasgow Coma Scale motor score at admission (p = 0.04) and lesions on DWI sequences in the substantia nigra and mesencephalic tegmentum (SN-T, p = 0.001) were associated with the proportion of GMT with ICP > 20 mm Hg. In multivariable linear regression, lesions on DWI sequences in SN-T (8% of GMT with ICP > 20 mm Hg, 95% CI 3%-13%, p = 0.004) and young age (-0.2% of GMT with ICP > 20 mm Hg, 95% CI -0.07% to -0.3%, p = 0.002) were associated with increased ICP.

CONCLUSIONS

Increased ICP occurs in approximately one-third of patients with severe TBI who have DAI. Age and lesions on DWI sequences in the central mesencephalon (i.e., SN-T) are associated with elevated ICP. These findings suggest that MR lesion localization may aid prediction of increased ICP in patients with DAI.

A clinical prediction model for raised intracranial pressure in patients with traumatic brain injuries

BACKGROUND

Intracranial hypertension is believed to contribute to secondary brain insult in traumatically brain injured patients. Currently, the diagnosis of intracranial hypertension requires intracranial monitoring or advanced imaging. Unfortunately, prehospital transport times can be prolonged, delaying time to the initial radiographic assessment. The aim of this study was to identify clinical variables associated with raised intracranial pressure (ICP) prior to the completion of neuroimaging.

METHODS

We performed a retrospective cohort study of head injured patients over a 3-year period. Patients were labeled as having increased ICP if they had a single reading of ICP greater than 20 mm Hg within 1 hour of ICP monitor insertion or computed tomography findings suggestive of raised ICP. Patient and clinical characteristics were analyzed using stepwise multivariable logistic regression with ICP as the dependent variable.

RESULTS

Of 701 head injured patients identified, 580 patients met inclusion criteria. Mean age was 48.65 ± 21 years, 73.3% were male. The mean Injury Severity Score was 22.71 ± 12.38, and the mean Abbreviated Injury Scale for body region head was 3.34 ± 1.06. Overall mortality was 14.7%. Only 46 (7.9%) patients had an ICP monitor inserted; however, a total of 107 (18%) patients met the definition of raised ICP. The mortality rate for patients with raised ICP was 50.4%. Independent predictors of raised ICP were as follows: age, older than 55 years (odds ratio [OR], 2.26; 95% confidence interval [CI], 1.35-3.76), pupillary fixation (OR, 5.76; 95% CI, 3.16-10.50), signs of significant head trauma (OR, 2.431; 95% CI, 1.39-4.26), and need for intubation (OR, 3.589; 95% CI, 2.10-6.14).

CONCLUSION

This study identified four independent variables associated with raised ICP and incorporated these findings into a preliminary risk assessment scale that can be implemented at the bedside to identify patients at significant risk of raised ICP. Future work is needed to prospectively validate these findings prior to clinical implementation.

LEVEL OF EVIDENCE

Prognostic, Epidemiological, level III.

The Role of Temporal Lobectomy as a Part of Surgical Resuscitation in Patients with Severe Traumatic Brain Injury

Background:

Traumatic brain injuries (TBIs) are serious morbidity and mortality risk for especially in the young population. Primary and secondary injury mechanisms may cause cerebral edema and intracranial hypertension. The target point of the TBI treatment is lowering the intracranial pressure medically or surgically if indicated.

Methods:

The files of the patients with severe brain injury admitted between January 2015 and December 2017 were reviewed retrospectively. Patients who underwent decompression surgery due to severe brain injury ([The Glasgow Coma Scale [GCS] score] <8) and additional temporal lobectomy were included in the study group.

Results:

Ten patients were included in the study during the 3 years. All the patients were suffering from blunt severe TBI. Traumatic etiology was vehicle traffic accident in six cases, nonvehicle traffic accident in two cases, and falling from height in two cases. All the cases suffered from blunt trauma. The admission GCS of the patients was 4–7 (mean = 5.5). Right-sided decompression surgery and lobectomy were performed for seven patients and left-sided in three cases. The postoperational survival was 60%. All the survivors were functionally independent with mild cognitive disturbances.

Conclusion:

Temporal lobectomy might be added to the surgery to apply all the interventions available in combat with progressively increasing intracerebral pressure as a part of surgical resuscitation.

Neutrophils in traumatic brain injury (TBI): friend or foe?

Our knowledge of the pathophysiology about traumatic brain injury (TBI) is still limited. Neutrophils, as the most abundant leukocytes in circulation and the first-line transmigrated immune cells at the sites of injury, are highly involved in the initiation, development, and recovery of TBI. Nonetheless, our understanding about neutrophils in TBI is obsolete, and mounting evidences from recent studies have challenged the conventional views. This review summarizes what is known about the relationships between neutrophils and pathophysiology of TBI. In addition, discussions are made on the complex roles as well as the controversial views of neutrophils in TBI.

Initial intracranial pressure as a prognosticator in head-injured patients undergoing decompressive craniectomy

Purpose

To examine the prognostic discrimination and prediction of initial intracranial pressure (ICP) in patients with traumatic brain injury (TBI) undergoing decompressive craniectomy (DC).

Results

The relationship between the initial ICP value and prognosis was quantified, and higher values indicated worse patient outcomes. Univariate analysis showed that the initial ICP value was significantly associated with mortality (odds ratio: 1.272, 95% confidence interval: 1.116-1.449; P<0.001) and unfavorable outcomes (odds ratio: 1.256, 95% confidence interval: 1.160-1.360; P<0.001). After adjustment for related outcome predictors of TBI in multivariate regression, the initial ICP value remained an independent predictor of unfavorable outcomes (odds ratio: 1.251, 95% confidence interval: 1.140-1.374; P=0.015) and mortality (odds ratio: 1.162, 95% confidence interval: 1.093-1.321; P=0.019).

Methods

A retrospective study was conducted in 133 TBI patients after DC. Initial ICP was defined as the first ICP recorded during surgery. Mortality and Glasgow Outcome Scale score at the end of follow-up were used as outcome measures. Unfavorable and favorable outcomes were classified by a Glasgow Outcome Scale score of 1 to 3 and 4 to 5, respectively. We used binary logistic and proportional odds regression for prognostic analyses.

Conclusion

For TBI patients undergoing DC, the initial ICP value provides great prognostic discrimination and is an independent predictor of unfavorable outcomes and mortality. We suggest that the initial ICP be included as a prognosticator in the overall assessment of prognosis of head-injured patients after DC.

Evaluation of Physiologic Alterations during Prehospital Paramedic-Performed Rapid Sequence Intubation

OBJECTIVE

Physiologic alterations during rapid sequence intubation (RSI) have been studied in several emergency airway management settings, but few data exist to describe physiologic alterations during prehospital RSI performed by ground-based paramedics. To address this evidence gap and provide guidance for future quality improvement initiatives in our EMS system, we collected electronic monitoring data to evaluate peri-intubation vital signs changes occurring during prehospital RSI.

METHODS

Electronic patient monitor data files from cases in which paramedic RSI was attempted were prospectively collected over a 15-month study period to supplement the standard EMS patient care documentation. Cases were analyzed to identify peri-intubation changes in oxygen saturation, heart rate, and blood pressure.

RESULTS

Data from 134 RSI cases were available for analysis. Paramedic-assigned prehospital diagnostic impression categories included neurologic (42%), respiratory (26%), toxicologic (22%), trauma (9%), and cardiac (1%). The overall intubation success rate (95%) and first-attempt success rate (82%) did not differ across diagnostic impression categories. Peri-intubation desaturation (SpO₂ decrease to below 90%) occurred in 43% of cases, and 70% of desaturation episodes occurred on first-attempt success. The incidence of desaturation varied among patient categories, with a respiratory diagnostic impression associated with more frequent, more severe, and more prolonged desaturations, as well as a higher incidence of accompanying cardiovascular instability. Bradycardia (HR decrease to below 60 bpm) occurred in 13% of cases, and 60% of bradycardia episodes occurred on first-attempt success. Hypotension (systolic blood pressure decrease to below 90 mmHg) occurred in 7% of cases, and 63% of hypotension episodes occurred on first-attempt success. Peri-intubation cardiac arrest occurred in 2 cases, one of which was on first-attempt success. Only 11% of desaturations and no instances of bradycardia were reflected in the standard EMS patient care documentation.

CONCLUSIONS

In this study, the majority of peri-intubation physiologic alterations occurred on first-attempt success, highlighting that first-attempt success is an incomplete and potentially deceptive measure of intubation quality. Supplementing the standard patient care documentation with electronic monitoring data can identify unrecognized physiologic instability during prehospital RSI and provide valuable guidance for quality improvement interventions.

The Neurological Wake-up Test-A Role in Neurocritical Care Monitoring of Traumatic Brain Injury Patients?

The most fundamental clinical monitoring tool in traumatic brain injury (TBI) patients is the repeated clinical examination. In the severe TBI patient treated by continuous sedation in a neurocritical care (NCC) unit, sedation interruption is required to enable a clinical evaluation (named the neurological wake-up test; NWT) assessing the level of consciousness, pupillary diameter and reactivity to light, and presence of focal neurological deficits. There is a basic conflict regarding the NWT in the NCC setting; can the clinical information obtained by the NWT justify the risk of inducing a stress response in a severe TBI patient? Furthermore, in the presence of advanced multimodal monitoring and neuroimaging, is the NWT necessary to identify important clinical alterations? In studies of severe TBI patients, the NWT was consistently shown to induce a stress reaction including brief increases in intracranial pressure (ICP) and changes in cerebral perfusion pressure (CPP). However, it has not been established whether these short-lived ICP and CPP changes are detrimental to the injured brain. Daily interruption of sedation is associated with a reduced ventilator time, shorter hospital stay and reduced mortality in many studies of general intensive care unit patients, although such clinical benefits have not been firmly established in TBI. To date, there is no consensus on the use of the NWT among NCC units and systematic studies are scarce. Thus, additional studies evaluating the role of the NWT in clinical decision-making are needed. Multimodal NCC monitoring may be an adjunct in assessing in which TBI patients the NWT can be safely performed. At present, the NWT remains the golden standard for clinical monitoring and detection of neurological changes in NCC and could be considered in TBI patients with stable baseline ICP and CPP readings. The focus of the present review is an overview of the existing literature on the role of the NWT as a clinical monitoring tool for severe TBI patients.

Chronic global analysis of vascular permeability and cerebral blood flow after bone marrow stromal cell treatment of traumatic brain injury in the rat: A long-term MRI study

Vascular permeability and hemodynamic alteration in response to the transplantation of human bone marrow stromal cells (hMSCs) after traumatic brain injury (TBI) were longitudinally investigated in non directly injured and normal-appearing cerebral tissue using magnetic resonance imaging (MRI). Male Wistar rats (300-350g, n=30) subjected to controlled cortical impact TBI were intravenously injected with 1ml of saline (at 6-h or 1-week post-injury, n=5/group) or with hMSCs in suspension (∼3×10⁶ hMSCs, at 6-h or 1-week post-injury, n=10/group). MRI measurements of T2-weighted imaging, cerebral blood flow (CBF) and blood-to-brain transfer constant (Ki) of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA), and neurological behavioral estimates were performed on all animals at multiple time points up to 3-months post-injury. Our long-term imaging data show that blood-brain barrier (BBB) breakdown and hemodynamic disruption after TBI, as revealed by Ki and CBF, respectively, affect both hemispheres of the brain in a diffuse manner. Our data reveal a sensitive vascular permeability and hemodynamic reaction in response to the time-dependent transplantation of hMSCs. A more rapid reduction of Ki following cell treatment is associated with a higher level of CBF in the injured brain, and acute (6h) cell administration leads to enhanced therapeutic effects on both the recovery of vascular integrity and stabilization of cerebral perfusion compared to delayed (1w) cell engraftment. Our results indicate that cell-enhanced BBB reconstitution plays an important role in underlying the restoration of CBF in the injured brain, which in turn, contributes to the improvement of functional outcome.

Hyperosmolar therapy in pediatric traumatic brain injury: a retrospective study

OBJECTIVES

The objectives of the study are to describe the use of hyperosmolar therapy in pediatric traumatic brain injury (TBI) and examine its effect on intracranial pressure (ICP) and cerebral perfusion pressure (CPP).

DESIGN

A retrospective review of patients with severe TBI admitted to the pediatric intensive care unit (PICU) was conducted. Inclusion criteria were ICP monitoring and administration of a hyperosmolar agent (20 % mannitol or 3 % hypertonic saline) within 48 h of PICU admission; for which dose and timing were recorded. For the first two boluses received for increased ICP (>20 mmHg), the impact on ICP and CPP was assessed during the following 4 h, using repeated measures ANOVA. Co-interventions to control ICP (additional hyperosmolar agent, propofol, or barbiturate bolus) and serum sodium were also documented.

SETTING

A tertiary care pediatric hospital center.

PATIENTS

Children aged 1 month to 18 years, with severe traumatic brain injury (Glasgow Coma Score ≤ 8) and intracranial pressure (ICP) monitor.

RESULTS

Sixty-four patients were eligible, of which 16 met inclusion criteria. Average age was 11 years (SD ± 4) and median Glasgow Coma Score was 6 (range 4-7). Seventy percent of boluses were 3 % hypertonic saline, with no identified baseline difference associated with this initial choice. Both mannitol and hypertonic saline were followed by a non-significant decrease in ICP (mannitol, p = 0.055 and hypertonic saline, p = 0.096). There was no significant change in CPP post bolus. A co-intervention occurred in 69 % of patients within the 4 h post hyperosmolar agent, and eight patients received continuous 3 % saline.

CONCLUSION

In pediatric TBI with intracranial hypertension, mannitol and 3 % hypertonic saline are commonly used, but dose and therapeutic threshold for use vary without clear indications for one versus another. Controlled trials are warranted, but several barriers were identified, including high exclusion rate, multiple co-interventions, and care variability.

Today's Approach to Treating Brain Swelling in the Neuro Intensive Care Unit

Brain swelling is an urgent clinical problem that frequently accompanies ischemic stroke, brain hemorrhage, and traumatic brain injury; it increases morbidity and mortality associated with them. It occurs due to failure of membrane transporters and leakage of the blood-brain barrier (BBB), resulting in combination of cytotoxic, ionic, and vasogenic edema. Currently, decompressive craniectomy and osmotherapy are the mainstays of management, but these therapies do not halt the underlying molecular cascade leading to brain swelling. Recent advances in the molecular underpinnings of cerebral edema have opened up possibilities of newer targeted therapeutic options. Here the authors outline the current approach for rapid diagnosis and intervention to reduce mortality and morbidity associated with brain swelling.

Reliable Collection of Real-Time Patient Physiologic Data from less Reliable Networks: a "Monitor of Monitors" System (MoMs)

Research and practice based on automated electronic patient monitoring and data collection systems is significantly limited by system down time. We asked whether a triple-redundant Monitor of Monitors System (MoMs) to collect and summarize key information from system-wide data sources could achieve high fault tolerance, early diagnosis of system failure, and improve data collection rates. In our Level I trauma center, patient vital signs(VS) monitors were networked to collect real time patient physiologic data streams from 94 bed units in our various resuscitation, operating, and critical care units. To minimize the impact of server collection failure, three BedMaster® VS servers were used in parallel to collect data from all bed units. To locate and diagnose system failures, we summarized critical information from high throughput datastreams in real-time in a dashboard viewer and compared the before and post MoMs phases to evaluate data collection performance as availability time, active collection rates, and gap duration, occurrence, and categories. Single-server collection rates in the 3-month period before MoMs deployment ranged from 27.8 % to 40.5 % with combined 79.1 % collection rate. Reasons for gaps included collection server failure, software instability, individual bed setting inconsistency, and monitor servicing. In the 6-month post MoMs deployment period, average collection rates were 99.9 %. A triple redundant patient data collection system with real-time diagnostic information summarization and representation improved the reliability of massive clinical data collection to nearly 100 % in a Level I trauma center. Such data collection framework may also increase the automation level of hospital-wise information aggregation for optimal allocation of health care resources.

Diffuse Axonal Injury: Epidemiology, Outcome and Associated Risk Factors

Diffuse axonal injury (DAI), a type of traumatic injury, is known for its severe consequences. However, there are few studies describing the outcomes of DAI and the risk factors associated with it. This study aimed to describe the outcome for patients with a primary diagnosis of DAI 6 months after trauma and to identify sociodemographic and clinical factors associated with mortality and dependence at this time point. Seventy-eight patients with DAI were recruited from July 2013 to February 2014 in a prospective cohort study. Patient outcome was analyzed using the Extended Glasgow Outcome Scale (GOS-E) within 6 months of the traumatic injury. The mean Injury Severity Score was 35.0 (SD = 11.9), and the mean New Injury Severity Score (NISS) was 46.2 (SD = 15.9). Mild DAI was observed in 44.9% of the patients and severe DAI in 35.9%. Six months after trauma, 30.8% of the patients had died, and 45.1% had shown full recovery according to the GOS-E. In the logistic regression model, the severity variables - DAI with hypoxia, as measured by peripheral oxygen saturation, and hypotension with NISS value - had a statistically significant association with patient mortality; on the other hand, severity of DAI and length of hospital stay were the only significant predictors for dependence. Therefore, severity of DAI emerged as a risk factor for both mortality and dependence.

The role of cardiac troponin I in prognostication of patients with isolated severe traumatic brain injury

BACKGROUND

Cardiac dysfunction is frequently observed after severe traumatic brain injury (sTBI); however, its significance is poorly understood. Our study sought to elucidate the association of cardiac troponin I (cTnI) elevation with all-cause in-hospital mortality following isolated sTBI (brain Abbreviated Injury Scale score ≥3 and admission Glasgow Coma Scale score ≤8, no Abbreviated Injury Scale score ≥3 to any other bodily regions).

METHODS

We retrospectively reviewed all adult patients (aged ≥18 years) with isolated sTBI admitted to a Level I trauma center between June 2007 and January 2014. Patients must have cTnI values within 24 hours of admission. Mortality risks were examined by Cox proportional hazard model.

RESULTS

Of 580 patients identified, 30.9% had detectable cTnI in 24 hours of admission. The median survival time was 4.19 days (interquartile range, 1.27-11.69). When adjusted for potential confounders, patients in the highest cTnI category (≥0.21 ng/mL) had a significantly higher risk of in-hospital mortality (hazard ratio, 1.39; 95% confidence interval, 1.04-1.88) compared with patients with undetectable cTnI. Mortality risk increased with higher troponin levels (p < 0.0001). This association was more pronounced in patients aged 65 years or younger (hazard ratio, 2.28; 95% confidence interval, 1.53-3.40; p < 0.0001) while, interestingly, insignificant in those older than 65 years (p = 0.0826).

CONCLUSION

Among patients with sTBI, cTnI elevation is associated with all-cause in-hospital mortality via a nonlinear positive trend. Age modified the effect of cTnI on mortality.

LEVEL OF EVIDENCE

Prognostic and epidemiologic study, level III.

Data collection and interpretation

Patient monitoring is routinely performed in all patients who receive neurocritical care. The combined use of monitors, including the neurologic examination, laboratory analysis, imaging studies, and physiological parameters, is common in a platform called multi-modality monitoring (MMM). However, the full potential of MMM is only beginning to be realized since for the most part, decision making historically has focused on individual aspects of physiology in a largely threshold-based manner. The use of MMM now is being facilitated by the evolution of bio-informatics in critical care including developing techniques to acquire, store, retrieve, and display integrated data and new analytic techniques for optimal clinical decision making. In this review, we will discuss the crucial initial steps toward data and information management, which in this emerging era of data-intensive science is already shifting concepts of care for acute brain injury and has the potential to both reshape how we do research and enhance cost-effective clinical care.

Computer Modelling Using Prehospital Vitals Predicts Transfusion and Mortality

OBJECTIVE

Test computer-assisted modeling techniques using prehospital vital signs of injured patients to predict emergency transfusion requirements, number of intensive care days, and mortality, compared to vital signs alone.

METHODS

This single-center retrospective analysis of 17,988 trauma patients used vital signs data collected between 2006 and 2012 to predict which patients would receive transfusion, require 3 or more days of intensive care, or die. Standard transmitted prehospital vital signs (heart rate, blood pressure, shock index, and respiratory rate) were used to create a regression model (PH-VS) that was internally validated and evaluated using area under the receiver operating curve (AUROC). Transfusion records were matched with blood bank records. Documentation of death and duration of intensive care were obtained from the trauma registry.

RESULTS

During the course of their hospital stay, 720 of the 17,988 patients in the study population died (4%), 2,266 (12.6%) required at least a 3-day stay in the intensive care unit (ICU), 1,171 (6.5%) required transfusions, and 210 (1.2%) received massive transfusions. The PH-VS model significantly outperformed any individual vital sign across all outcomes (average AUROC = 0.82), The PH-VS model correctly predicted that 512 of 777 (65.9%) and 580 of 931 (62.3%) patients in the study population would receive transfusions within the first 2 and 6 hours of admission, respectively.

CONCLUSIONS

The predictive ability of individual vital signs to predict outcomes is significantly enhanced with the model. This could support prehospital triage by enhancing decision makers' ability to match critically injured patients with appropriate resources with minimal delays.

Effectiveness of Pharmacological Therapies for Intracranial Hypertension in Children With Severe Traumatic Brain Injury--Results From an Automated Data Collection System Time-Synched to Drug Administration

OBJECTIVES

To describe acute cerebral hemodynamic effects of medications commonly used to treat intracranial hypertension in children with traumatic brain injury. Currently, data supporting the efficacy of these medications are insufficient.

DESIGN

In this prospective observational study, intracranial hypertension (intracranial pressure ≥ 20 mm Hg for > 5 min) was treated by clinical protocol. Administration times of medications for intracranial hypertension (fentanyl, 3% hypertonic saline, mannitol, and pentobarbital) were prospectively recorded and synchronized with an automated database that collected intracranial pressure and cerebral perfusion pressure every 5 seconds. Intracranial pressure crises confounded by external stimulation or mechanical ventilator adjustments were excluded. Mean intracranial pressure and cerebral perfusion pressure from epochs following drug administration were compared with baseline values using Kruskal-Wallis analysis of variance and Dunn test. Frailty modeling was used to analyze the time to intracranial pressure crisis resolution. Mixed-effect models compared intracranial pressure and cerebral perfusion pressure 5 minutes after the medication versus baseline and rates of treatment failure.

SETTING

A tertiary care children's hospital.

PATIENTS

Children with severe traumatic brain injury (Glasgow Coma Scale score ≤ 8).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We analyzed 196 doses of fentanyl, hypertonic saline, mannitol, and pentobarbital administered to 16 children (median: 12 doses per patient). Overall, intracranial pressure significantly decreased following the administration of fentanyl, hypertonic saline, and pentobarbital. After controlling for administration of multiple medications, intracranial pressure was decreased following hypertonic saline and pentobarbital administration; cerebral perfusion pressure was decreased following fentanyl and was increased following hypertonic saline administration. After adjusting for significant covariates (including age, Glasgow Coma Scale score, and intracranial pressure), hypertonic saline was associated with a two-fold faster resolution of intracranial hypertension than either fentanyl or pentobarbital. Fentanyl was significantly associated with the most frequent treatment failure.

CONCLUSIONS

Intracranial pressure decreased after multiple drug administrations, but hypertonic saline may warrant consideration as the first-line drug for treating intracranial hypertension, as it was associated with the most favorable cerebral hemodynamics and fastest resolution of intracranial hypertension.

Intracranial pressure monitoring: fundamental considerations and rationale for monitoring

Traumatic brain injury (TBI) is a major cause of death and disability worldwide. In large part critical care for TBI is focused on the identification and management of secondary brain injury. This requires effective neuromonitoring that traditionally has centered on intracranial pressure (ICP). The purpose of this paper is to review the fundamental literature relative to the clinical application of ICP monitoring in TBI critical care and to provide recommendations on how the technique maybe applied to help patient management and enhance outcome. A PubMed search between 1980 and September 2013 identified 2,253 articles; 244 of which were reviewed in detail to prepare this report and the evidentiary tables. Several important concepts emerge from this review. ICP monitoring is safe and is best performed using a parenchymal monitor or ventricular catheter. While the indications for ICP monitoring are well established, there remains great variability in its use. Increased ICP, particularly the pattern of the increase and ICP refractory to treatment is associated with increased mortality. Class I evidence is lacking on how monitoring and management of ICP influences outcome. However, a large body of observational data suggests that ICP management has the potential to influence outcome, particularly when care is targeted and individualized and supplemented with data from other monitors including the clinical examination and imaging.

Transocular ultrasound measurement of the optic nerve sheath diameter can identify elevated intracranial pressure in trauma patients

Background

Prompt identification of elevated intracranial pressure (eICP) is life-saving. Physical exam alone often fails to identify this problem and invasive monitoring is not always utilized appropriately. A non-invasive, rapid, reliable technique to detect eICP is needed and optic nerve sheath diameter (ONSD) is known to be a valid surrogate. Historically, ONSD in patients with eICP above 20 mmHg varied from 0.5 to 0.7 cm. Receiver operator curves predict that diameters below 0.5 to 0.58 cm correspond to normal pressures. Interobserver variability is low (0.01--0.03 cm). The learning curve was 25 and 10 procedures for novice and experienced sonographers, respectively. We report our initial experience using ultrasound to measure ONSD during initial trauma evaluation.

Study design

Transocular ultrasound was used to determine ONSD after traumatic brain injury. Data were correlated with CT and exam findings or measured ICP. Measurements were performed by a single trauma surgeon. Time to perform the measurement was recorded. Relevant literature from the past 15 years was reviewed.

Results

Physical exam was not a reliable indicator of eICP. In patients with eICP requiring surgery, ONSD averaged 0.62 cm. Normal pressures were ensured if the ONDS was <0.50 cm (95% CI 0.469–0.540 cm, p < 0.001). Intraobserver variability was low (0.01--0.02 cm). Average time to perform the exam was less than 2 min.

Conclusions

Determining ONSD with ultrasound is easy to learn, precise, and inexpensive. An ONSD of less than 5 mm ensures no eICP. This procedure can be added to the evaluation of trauma patients with no delay in care. Future prospective studies may validate and incorporate this technique into the trauma surgeon's armamentarium.

Predicting secondary insults after severe traumatic brain injury

BACKGROUND

Secondary insults such as hypotension, hypoxia, cerebral hypoperfusion, and intracranial hypertension are associated with poor outcome following severe traumatic brain injury (TBI). Preventing and minimizing the effect of secondary insults are essential in the management of severe TBI. At present, clinicians have no way to predict the development of these events, limiting their ability to plan appropriate timing of interventions. We hypothesized that processing continuous vital signs (VS) data using machine learning methods could predict the development of future intracranial hypertension.

METHODS

Continuous VS including intracranial pressure (ICP), heart rate, systolic blood pressure, and mean arterial pressure data were collected from adult patients admitted to a single Level I trauma center requiring an ICP monitor. We tested the ability of Nearest Neighbor Regression (NNR) to predict changes in ICP by algorithmically learning from the patients' past physiology.

RESULTS

Continuous VS were collected on 132 adult patients over a minimum of 3 hours per patient (5,466 hours total; 65,600 data points). Bland-Altman plots show that NNR provides good agreement in predicting actual ICP with a bias of 0.02 (±2 SD = 4 mm Hg) for the subsequent 5 minutes and -0.02 (±2 SD = 10 mm Hg) for the subsequent 2 hours.

CONCLUSION

We have demonstrated that with the use of physiologic data, it is possible to predict with reasonable accuracy future ICP levels following severe TBI. NNR predicts ICP changes in clinically useful time frames. This ability to predict events may allow clinicians to make better decisions about the timing of necessary interventions, and this method could support the future development of minimally invasive ICP monitoring systems, which may lead to better overall clinical outcomes after severe TBI.

LEVEL OF EVIDENCE

Prognostic study, level III.

Ultrasound measurement of optic nerve diameter and optic nerve sheath diameter in healthy Chinese adults

BACKGROUND

Measurement of optic nerve sheath diameter (ONSD) is a fast and non-invasive method in detecting elevated intracranial pressure. However, the reported normal range of ONSD was inconsistent. The objective of the study was to determine the normal range of ONSD in healthy Chinese adults.

METHODS

Eyeball transverse diameter (ETD), optic nerve diameter (OND), and ONSD were measured by ultrasound examination in healthy adult volunteers. The OND and ONSD were assessed 3 mm behind the globe. The section showing maximal transverse diameter of the eyeball was frozen and the diameter was measured. Each ETD, OND and ONSD was examined twice and the mean value was calculated.

RESULTS

A total of 519 healthy volunteers were included in the study. The median (interquartile range) of ETD, OND and ONSD were 22.3 (21.6 to 23.1) mm, 3.2 (2.9 to 3.4) mm, and 5.1 (4.7 to 5.4) mm, respectively. The 95% percentile of ONSD was 5.9 mm. There was no significant difference in ETD, OND or ONSD between male and female, or between left and right eye. ONSD was significantly correlated with OND (r = 0.62, P < 0.001), and the median OND/ONSD ratio (interquartile range) was 0.63 (0.59 to 0.67).

CONCLUSIONS

The median and the 95% percentile of sonographic measurement of ONSD are 5.1 mm and 5.9 mm in healthy Chinese adults. The ONSD is correlated with OND, while independent of gender, age, height, weight and ETD. The median OND/ONSD ratio is 0.63 and this parameter warrants further investigation in patients with brain injury.

Significant modification of traditional rapid sequence induction improves safety and effectiveness of pre-hospital trauma anaesthesia

INTRODUCTION

Rapid Sequence Induction of anaesthesia (RSI) is the recommended method to facilitate emergency tracheal intubation in trauma patients. In emergency situations, a simple and standardised RSI protocol may improve the safety and effectiveness of the procedure. A crucial component of developing a standardised protocol is the selection of induction agents. The aim of this study is to compare the safety and effectiveness of a traditional RSI protocol using etomidate and suxamethonium with a modified RSI protocol using fentanyl, ketamine and rocuronium.

METHODS

We performed a comparative cohort study of major trauma patients undergoing pre-hospital RSI by a physician-led Helicopter Emergency Medical Service. Group 1 underwent RSI using etomidate and suxamethonium and Group 2 underwent RSI using fentanyl, ketamine and rocuronium. Apart from the induction agents, the RSI protocol was identical in both groups. Outcomes measured included laryngoscopy view, intubation success, haemodynamic response to laryngoscopy and tracheal intubation, and mortality.

RESULTS

Compared to Group 1 (n = 116), Group 2 RSI (n = 145) produced significantly better laryngoscopy views (p = 0.013) and resulted in significantly higher first-pass intubation success (95% versus 100%; p = 0.007). A hypertensive response to laryngoscopy and tracheal intubation was less frequent following Group 2 RSI (79% versus 37%; p < 0.0001). A hypotensive response was uncommon in both groups (1% versus 6%; p = 0.05). Only one patient in each group developed true hypotension (SBP < 90 mmHg) on induction.

CONCLUSIONS

In a comparative, cohort study, pre-hospital RSI using fentanyl, ketamine and rocuronium produced superior intubating conditions and a more favourable haemodynamic response to laryngoscopy and tracheal intubation. An RSI protocol using fixed ratios of these agents delivers effective pre-hospital trauma anaesthesia.

Hypertonic saline for the management of raised intracranial pressure after severe traumatic brain injury

Hyperosmolar agents are commonly used as an initial treatment for the management of raised intracranial pressure (ICP) after severe traumatic brain injury (TBI). They have an excellent adverse-effect profile compared to other therapies, such as hyperventilation and barbiturates, which carry the risk of reducing cerebral perfusion. The hyperosmolar agent mannitol has been used for several decades to reduce raised ICP, and there is accumulating evidence from pilot studies suggesting beneficial effects of hypertonic saline (HTS) for similar purposes. An ideal therapeutic agent for ICP reduction should reduce ICP while maintaining cerebral perfusion (pressure). While mannitol can cause dehydration over time, HTS helps maintain normovolemia and cerebral perfusion, a finding that has led to a large amount of pilot data being published on the benefits of HTS, albeit in small cohorts. Prophylactic therapy is not recommended with mannitol, although it may be beneficial with HTS. To date, no large clinical trial has been performed to directly compare the two agents. The best current evidence suggests that mannitol is effective in reducing ICP in the management of traumatic intracranial hypertension and carries mortality benefit compared to barbiturates. Current evidence regarding the use of HTS in severe TBI is limited to smaller studies, which illustrate a benefit in ICP reduction and perhaps mortality.

'Big data' approaches to trauma outcome prediction and autonomous resuscitation

Massive clinical digital data routinely collected by high throughput biomedical devices provide opportunities and challenges for optimal use. This article discusses how such data are used in learning prediction models at level 1 trauma centres to support decision making in trauma patients.

Emerging therapies in traumatic brain injury

Despite decades of basic and clinical research, treatments to improve outcomes after traumatic brain injury (TBI) are limited. However, based on the recent recognition of the prevalence of mild TBI, and its potential link to neurodegenerative disease, many new and exciting secondary injury mechanisms have been identified and several new therapies are being evaluated targeting both classic and novel paradigms. This includes a robust increase in both preclinical and clinical investigations. Using a mechanism-based approach the authors define the targets and emerging therapies for TBI. They address putative new therapies for TBI across both the spectrum of injury severity and the continuum of care, from the field to rehabilitation. They discussTBI therapy using 11 categories, namely, (1) excitotoxicity and neuronal death, (2) brain edema, (3) mitochondria and oxidative stress, (4) axonal injury, (5) inflammation, (6) ischemia and cerebral blood flow dysregulation, (7) cognitive enhancement, (8) augmentation of endogenous neuroprotection, (9) cellular therapies, (10) combination therapy, and (11) TBI resuscitation. The current golden age of TBI research represents a special opportunity for the development of breakthroughs in the field.

Responsiveness to therapy for increased intracranial pressure in traumatic brain injury is associated with neurological outcome

In patients with severe traumatic brain injury, increased intracranial pressure (ICP) is associated with poor functional outcome or death. Hypertonic saline (HTS) is a hyperosmolar therapy commonly used to treat increased ICP; this study aimed to measure initial patient response to HTS and look for association with patient outcome. Patients >17 years old, admitted and requiring ICP monitoring between 2008 and 2010 at a large urban tertiary care facility were retrospectively enrolled. The first dose of hypertonic saline administered after admission for ICP >19mmHg was recorded and correlated with vital signs recorded at the bedside. The absolute and relative change in ICP at 1 and 2h after HTS administration was calculated. Patients were stratified by mortality and long-term (≥6 months) functional neurological outcome. We identified 46 patients who received at least 1 dose of HTS for ICP>19, of whom 80% were male, mean age 34.4, with a median post-resuscitation GCS score of 6. All patients showed a significant decrease in ICP 1h after HTS administration. Two hours post-administration, survivors showed a further decrease in ICP (43% reduction from baseline), while ICP began to rebound in non-survivors (17% reduction from baseline). When patients were stratified for long-term neurological outcome, results were similar, with a significant difference in groups by 2h after HTS administration. In patients treated with HTS for intracranial hypertension, those who survived or had good neurological outcome, when compared to those who died or had poor outcomes, showed a significantly larger sustained decrease in ICP 2h after administration. This suggests that even early in a patient's treatment, treatment responsiveness is associated with mortality or poor functional outcome. While this work is preliminary, it suggests that early failure to obtain a sustainable response to hyperosmolar therapy may warrant greater treatment intensity or therapy escalation.

Permutation entropy analysis of vital signs data for outcome prediction of patients with severe traumatic brain injury

Permutation entropy is computationally efficient, robust to outliers, and effective to measure complexity of time series. We used this technique to quantify the complexity of continuous vital signs recorded from patients with traumatic brain injury (TBI). Using permutation entropy calculated from early vital signs (initial 10-20% of patient hospital stay time), we built classifiers to predict in-hospital mortality and mobility, measured by 3-month Extended Glasgow Outcome Score (GOSE). Sixty patients with severe TBI produced a skewed dataset that we evaluated for accuracy, sensitivity and specificity. The overall prediction accuracy achieved 91.67% for mortality, and 76.67% for 3-month GOSE in testing datasets, using the leave-one-out cross validation. We also applied Receiver Operating Characteristic analysis to compare classifiers built from different learning methods. Those results support the applicability of permutation entropy in analyzing the dynamic behavior of TBI vital signs for early prediction of mortality and long-term patient outcomes.

Intraoperative secondary insults during extracranial surgery in children with traumatic brain injury

PURPOSE

Data on intraoperative secondary insults in pediatric traumatic brain injury (TBI) are limited.

METHODS

We examined intraoperative secondary insults during extracranial surgery in children with moderate-severe TBI and polytrauma and their association with postoperative head computed tomography (CT) scans, intracranial pressure (ICP), and therapeutic intensity level (TIL) scores 24 h after surgery. After IRB approval, we reviewed the records of children <18 years with a Glasgow Coma Scale score <13 who underwent extracranial surgery within 72 h of TBI. Definitions of secondary insults were as follows: systemic hypotension (SBP <70 + 2 × age or 90 mmHg), cerebral hypotension (cerebral perfusion pressure <40 mmHg), intracranial hypertension (ICP >20 mmHg), hypoxia (oxygen saturation <90 %), hypercarbia (end-tidal CO2 >45 mmHg), hypocarbia (end-tidal CO2 <30 mmHg without hypotension and in the absence of intracranial hypertension), hyperglycemia (blood glucose >200 mg/dL), hyperthermia (temperature >38 °C), and hypothermia (temperature <35 °C).

RESULTS

Data from 50 surgeries in 42 patients (median age 15.5 years, 25 males) revealed systemic hypotension during 78 %, hypocarbia during 46 %, and hypercarbia during 25 % surgeries. Intracranial hypertension occurred in 64 % and cerebral hypotension in 18 % surgeries with ICP monitoring (11/50). Hyperglycemia occurred during 17 % of the 29 surgeries with glucose monitoring. Cerebral hypotension and hypoxia were associated with postoperative intracranial hypertension (p = 0.02 and 0.03, respectively). We did not observe an association between intraoperative secondary insults and postoperative worsening of head CT scan or TIL score.

CONCLUSIONS

Intraoperative secondary insults were common during extracranial surgery in pediatric TBI. Intraoperative cerebral hypotension and hypoxia were associated with postoperative intracranial hypertension. Strategies to prevent secondary insults during extracranial surgery in TBI are needed.

Monitoring of acute traumatic brain injury in adults to prevent secondary brain damage

ABSTRACT: Traumatic brain injury is typically characterized by the primary injury initiating a cascade of pathologic changes that then lead to secondary brain injury. Secondary brain injury is amenable to different therapeutic options. Monitoring of otherwise occult pathologic changes involving oxygenation and metabolism is crucial for treatment decisions. Currently, decision-making is mainly based on measuring intracranial pressure and cerebral perfusion pressure. Importantly, extending neuromonitoring by including parameters reflecting cerebral perfusion, oxygenation and metabolism may improve treatment of traumatic brain injury patients by detecting neuronal damage despite optimal intracranial pressure or cerebral perfusion pressure and preventing unnecessarily aggressive treatment potentially causing local and systemic harm. In this review, the authors describe the advantages and disadvantages of contemporary, extended neuromonitoring methods in traumatic brain injury patients aimed at unmasking secondary brain damage as early as possible.

Timing of intracranial hypertension following severe traumatic brain injury

BACKGROUND

We asked whether continuous intracranial pressure (ICP) monitoring data could provide objective measures of the degree and timing of intracranial hypertension (ICH) in the first week of neurotrauma critical care and whether such data could be linked to outcome.

METHODS

We enrolled adult (>17 years old) patients admitted to our Level I trauma center within 6 h of severe TBI. ICP data were automatically captured and ICP 5-minute means were grouped into 12-hour time periods from admission (hour 0) to >7 days (hour 180). Means, maximum, percent time (% time), and pressure-times-time dose (PTD, mmHg h) of ICP >20 mmHg and >30 mmHg were calculated for each time period.

RESULTS

From 2008 to 2010, we enrolled 191 patients. Only 2.1% had no episodes of ICH. The timing of maximum PTD20 was relatively equally distributed across the 15 time periods. Median ICP, PTD20, %time20, and %time30 were all significantly higher in the 84-180 h time period than the 0-84 h time period. Stratified by functional outcome, those with poor functional outcome had significantly more ICH in hours 84-180. Multivariate analysis revealed that, after 84 h of monitoring, every 5% increase in PTD20 was independently associated with 21% higher odds of having a poor functional outcome (adjusted odds ratio = 1.21, 95% CI 1.02-1.42, p = 0.03).

CONCLUSIONS

Although early elevations in ICP occur, ICPs are the highest later in the hospital course than previously understood, and temporal patterns of ICP elevation are associated with functional outcome. Understanding this temporal nature of secondary insults has significant implications for management.