Hypertonic Saline is Superior to Mannitol for the Combined Effect on Intracranial Pressure and Cerebral Perfusion Pressure Burdens in Patients With Severe Traumatic Brain Injury

Comparison of mannitol and hypertonic saline solution for the treatment of suspected brain herniation during prehospital management of traumatic brain injury patients

BACKGROUND AND IMPORTANCE

Occurrence of mydriasis during the prehospital management of traumatic brain injury (TBI) may suggest severe intracranial hypertension (ICH) subsequent to brain herniation. The initiation of hyperosmolar therapy to reduce ICH and brain herniation is recommended. Whether mannitol or hypertonic saline solution (HSS) should be preferred is unknown.

OBJECTIVES

The objective of this study is to assess whether HSS, compared with mannitol, is associated with improved survival in adult trauma patients with TBI and mydriasis.

DESIGN/SETTING AND PARTICIPANTS

A retrospective observational cohort study using the French Traumabase national registry to compare the ICU mortality of patients receiving either HSS or mannitol. Patients aged 16 years or older with moderate to severe TBI who presented with mydriasis during prehospital management were included.

OUTCOME MEASURES AND ANALYSIS

We performed propensity score matching on a priori selected variables [i.e. age, sex and initial Coma Glasgow Scale (GCS)] with a ratio of 1 : 3 to ensure comparability between the two groups. The primary outcome was ICU mortality. The secondary outcomes were regression of pupillary abnormality during prehospital management, pulsatility index and diastolic velocity on transcranial Doppler within 24 h after TBI, early ICU mortality (within 48 h), ICU and hospital length of stay.

RESULTS

Of 31 579 patients recorded in the registry between 2011 and 2021, 1417 presented with prehospital mydriasis and were included: 1172 (82.7%) received mannitol and 245 (17.3%) received HSS. After propensity score matching, 720 in the mannitol group matched 240 patients in the HSS group. Median age was 41 years [interquartile ranges (IQR) 26-60], 1058 were men (73%) and median GCS was 4 (IQR 3-6). No significant difference was observed in terms of characteristics and prehospital management between the two groups. ICU mortality was lower in the HSS group (45%) than in the mannitol group (54%) after matching [odds ratio (OR) 0.68 (0.5-0.9), P  = 0.014]. No differences were identified between the groups in terms of secondary outcomes.

CONCLUSION

In this propensity-matched observational study, the prehospital osmotherapy with HSS in TBI patients with prehospital mydriasis was associated with a lower ICU mortality compared to osmotherapy with mannitol.

Impact of resuscitation adjuncts on postintubation hypotension in patients with isolated traumatic brain injury

INTRODUCTION

Postintubation hypotension (PIH) is a risk factor of endotracheal intubation (ETI) after injury. For those with traumatic brain injury (TBI), one episode of hypotension can potentiate that injury. This study aimed to identify the resuscitation adjuncts that may decrease the incidence of PIH in this patient population.

METHODS

This is a 4-year (2019-2022) prospective observational study at a level I trauma center. Adult (18 years or older) patients with isolated TBI requiring ETI in the trauma bay were included. Blood pressures were measured 15 minutes preintubation and postintubation. Primary outcome was PIH, defined as a decrease in systolic blood pressure of ≥20% from baseline or to ≤80 mm Hg, or any decrease in mean arterial pressure to ≤60 mm Hg. Multivariable logistic regression was performed to identify the associations of preintubation vasopressor, hypertonic saline (HTS), packed red blood cell, and crystalloids on PIH incidence.

RESULTS

Of the 490 enrolled patients, 16% had mild (head AIS, ≤2), 35% had moderate (head AIS, 3-4), and 49% had severe TBI (head AIS, ≥5). The mean ± SD age was 42 ± 22 years, and 71% were male. The median ISS, head AIS, and Glasgow Coma Scale were 26 (19-38), 4 (3-5), and 6 (3-11), respectively. The mean ± SD systolic blood pressure 15 minutes preintubation and postintubation were 118 ± 46 and 106 ± 45, respectively. Before intubation, 31% received HTS; 10%, vasopressors; 20%, crystalloids; and 14%, at least 1 U of packed red blood cell (median, 2 [1-2] U). Overall, 304 patients (62%) developed PIH. On multivariable regression analysis, preintubation use of vasopressors and HTS was associated with significantly decreased odds of PIH independent of TBI severity, 0.310 (0.102-0.944, p = 0.039) and 0.393 (0.219-0.70, p = 0.002), respectively.

CONCLUSION

Nearly two thirds of isolated TBI patients developed PIH. Preintubation vasopressors and HTS are associated with a decreased incidence of PIH. Such adjuncts should be considered prior to ETI in patients with suspected TBI.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level III.

Hyperosmolar Therapy in Elderly Neurosurgical Patients: Comparison of the Effect of Mannitol (20%) and Hypertonic Saline (3%) on Advanced Cardiovascular Parameters Using Transesophageal Echocardiography: A Preliminary Randomized Controlled Trial

OBJECTIVE

Osmotherapeutic agents increase the intravascular volume by withdrawing water from the brain followed by relative hypovolemia due to diuresis leading to significant changes in systemic hemodynamics which might have adverse consequences in the elderly. We studied the effect of mannitol (20%) and hypertonic saline (HTS) (3%) on left ventricular outflow tract velocity time integral (LVOT-VTI) and cardiac output (CO) in elderly patients undergoing supratentorial neurosurgical procedures using transesophageal echocardiography.

METHODS

We recruited 28 patients aged above 65 years undergoing supratentorial craniotomy who received equiosmolar solutions of 5.35 ml/kg of 3% HTS (group HS, n = 14) or 5 ml/kg of 20% mannitol (group M, n = 14). LVOT-VTI was recorded at baseline, 15, 30, 45, 60, and 90 minutes postinfusion and CO was derived. We also recorded heart rate, blood pressure, fluid balance, brain relaxation, vasopressor use, complications, and neurological outcome.

RESULTS

We found a significant decrease in LVOT-VTI at 45, and 60 minutes in group M as compared to group HS [mean (standard deviation), 16.76 (1.81) vs. 20.78 (1.87), P < 0.001, 17.4 (2.38) vs. 19.16 (2), P = 0.044, respectively]. We also found a corresponding significant fall in CO [3863.16 (845.87) vs. 4745.59 (1209.33) ml/minute, P = 0.034] and systolic blood pressure (P = 0.039), at 45 minutes in group M. Urine output was higher in group M (P < 0.001). All other parameters were comparable.

CONCLUSIONS

HTS appears to be associated with better systemic hemodynamics (LVOT-VTI, CO) while providing equivalent brain relaxation as mannitol in elderly patients. A future larger study is required to confirm our preliminary findings.

Comparing the effects of mannitol and hypertonic saline in severe traumatic brain injury patients with elevated intracranial pressure: a systematic review and meta-analysis

OBJECTIVES

Controlling elevated intracranial pressure following brain injury with hyperosmolar agents is one of the mainstay treatments in traumatic brain injury patients. In this study, we compared the effects of hypertonic saline (HS) and mannitol in reducing increased intracranial pressure.

METHODS

A total of 637 patients from 15 studies were included in our meta-analysis. The primary outcomes were mortality, the length of stay in the hospital and ICU, and the Glasgow Outcome Scale at follow-up.

RESULTS

The mortality in the mannitol group was not statistically different compared to the HS group (RR = 1.55; 95% CI = [0.98, 2.47], p = 0.06). The length of stay in the ICU was significantly shorter in the HS group (MD = 1.18, 95% CI = [0.44, 1.92], p < 0.01). In terms of favorable neurological outcomes, there was no significant difference between the two agents (RR = 0.92, 95% CI = [0.11, 7.96], p = 0.94). The duration of the effect was shorter in the mannitol group than in the HS group (MD = -0.67, 95% CI = [-1.00, -0.33], p < 0.01).

DISCUSSION

The results showed that HS and mannitol had similar effects in reducing ICP. Although the HS was associated with a longer duration of effect and shorter ICU stay, other secondary outcomes including mortality rate and favorable neurological outcomes were similar between the two drugs. In conclusion, considering the condition of each patient individually, HS could be a reasonable option than mannitol to reduce ICP in TBI patients.

Hypertonic Saline Versus Other Intracranial-Pressure-Lowering Agents for Patients with Acute Traumatic Brain Injury: A Systematic Review and Meta-analysis

Acute traumatic brain injury (TBI) is a major cause of mortality and disability worldwide. Intracranial pressure (ICP)-lowering is a critical management priority in patients with moderate to severe acute TBI. We aimed to evaluate the clinical efficacy and safety of hypertonic saline (HTS) versus other ICP-lowering agents in patients with TBI. We conducted a systematic search from 2000 onward for randomized controlled trials (RCTs) comparing HTS vs. other ICP-lowering agents in patients with TBI of all ages. The primary outcome was the Glasgow Outcome Scale (GOS) score at 6 months (PROSPERO CRD42022324370). Ten RCTs (760 patients) were included. Six RCTs were included in the quantitative analysis. There was no evidence of an effect of HTS on the GOS score (favorable vs. unfavorable) compared with other agents (risk ratio [RR] 0.82, 95% confidence interval [CI] 0.48-1.40; n = 406; 2 RCTs). There was no evidence of an effect of HTS on all-cause mortality (RR 0.96, 95% CI 0.60-1.55; n = 486; 5 RCTs) or total length of stay (RR 2.36, 95% CI - 0.53 to 5.25; n = 89; 3 RCTs). HTS was associated with adverse hypernatremia compared with other agents (RR 2.13, 95% CI 1.09-4.17; n = 386; 2 RCTs). The point estimate favored a reduction in uncontrolled ICP with HTS, but this was not statistically significant (RR 0.52, 95% CI 0.26-1.04; n = 423; 3 RCTs). Most included RCTs were at unclear or high risk of bias because of lack of blinding, incomplete outcome data, and selective reporting. We found no evidence of an effect of HTS on clinically important outcomes and that HTS is associated with adverse hypernatremia. The included evidence was of low to very low certainty, but ongoing RCTs may help to the reduce this uncertainty. In addition, heterogeneity in GOS score reporting reflects the need for a standardized TBI core outcome set.

Impact of the severity of brain injury on secondary adrenal insufficiency in traumatic brain injury patients and the influence of HPA axis dysfunction on prognosis

OBJECTIVE

To investigate secondary adrenal insufficiency post varying traumatic brain injuries' and its impact on prognosis.

METHODS

120 traumatic brain injury patients were categorized into mild, moderate and severe groups based on Glasgow Coma Scale. Adrenal function was evaluated through testing.

RESULTS

Secondary adrenal insufficiency rates were 0% (mild), 22.85% (moderate) and 44.82% (severe). Hypothalamus-pituitary-adrenal axis dysfunction rates were 14.81% (mild), 42.85% (moderate) and 63.79% (severe). Differences among groups were significant (p < .05). Patients with intact hypothalamus-pituitary-adrenal axis had shorter hospital stays and higher Glasgow Coma Scale scores. Receiver operating characteristic analysis of 24-h urinary free cortisol showed an area of 0.846, with a 17.62 μg/24h cutoff, 98.32% sensitivity and 52.37% specificity. In the low-dose adrenocorticotropic hormone test, with an 18 μg/dL cutoff, the receiver operating characteristic area was 0.546, with 46.28% sensitivity and 89.39% specificity.

CONCLUSION

As traumatic brain injury severity increases, secondary adrenal insufficiency incidence rises. The low-dose adrenocorticotropic hormone test is promising for hypothalamus-pituitary-adrenal axis evaluation. Patients with hypothalamus-pituitary-adrenal dysfunction experience prolonged hospitalization and worse prognosis.

Osmotherapy and the management of traumatic brain injury: still a dilemma

Despite extensive study and use, selecting an osmotherapy agent for traumatic brain injury remains a dilemma. This article explores the challenges in managing patients with traumatic brain injury and the ongoing debate surrounding the efficacy of different hyperosmolar agents as treatment options.

The establishment and validation of a prediction model for traumatic intracranial injury patients: a reliable nomogram

Objective

Traumatic brain injury (TBI) leads to death and disability. This study developed an effective prognostic nomogram for assessing the risk factors for TBI mortality.

Method

Data were extracted from an online database called "Multiparameter Intelligent Monitoring in Intensive Care IV" (MIMIC IV). The ICD code obtained data from 2,551 TBI persons (first ICU stay, >18 years old) from this database. R divided samples into 7:3 training and testing cohorts. The univariate analysis determined whether the two cohorts differed statistically in baseline data. This research used forward stepwise logistic regression after independent prognostic factors for these TBI patients. The optimal variables were selected for the model by the optimal subset method. The optimal feature subsets in pattern recognition improved the model prediction, and the minimum BIC forest of the high-dimensional mixed graph model achieved a better prediction effect. A nomogram-labeled TBI-IHM model containing these risk factors was made by nomology in State software. Least Squares OLS was used to build linear models, and then the Receiver Operating Characteristic (ROC) curve was plotted. The TBI-IHM nomogram model's validity was determined by receiver operating characteristic curves (AUCs), correction curve, Hosmer-Lemeshow test, integrated discrimination improvement (IDI), net reclassification improvement (NRI), and decision-curve analysis (DCA).

Result

The eight features with a minimal BIC model were mannitol use, mechanical ventilation, vasopressor use, international normalized ratio, urea nitrogen, respiratory rate, and cerebrovascular disease. The proposed nomogram (TBI-IHM model) was the best mortality prediction model, with better discrimination and superior model fitting for severely ill TBI patients staying in ICU. The model's receiver operating characteristic curve (ROC) was the best compared to the seven other models. It might be clinically helpful for doctors to make clinical decisions.

Conclusion

The proposed nomogram (TBI-IHM model) has significant potential as a clinical utility in predicting mortality in TBI patients.

Fluid therapy and traumatic brain injury: A narrative review

Traumatic brain injury (TBI) is an important health and social problem. The mechanism of damage of this entity could be divided into two phases: (1) a primary acute injury because of the traumatic event; and (2) a secondary injury due to the hypotension and hypoxia generated by the previous lesion, which leads to ischemia and necrosis of neural cells. Cerebral edema is one of the most important prognosis markers observed in TBI. In the early stages of TBI, the cerebrospinal fluid compensates the cerebral edema. However, if edema increases, this mechanism fails, increasing intracranial pressure. To avoid this chain effect, several treatments are applied in the clinical practice, including elevation of the head of the bed, maintenance of normothermia, pain and sedation drugs, mechanical ventilation, neuromuscular blockade, controlled hyperventilation, and fluid therapy (FT). The goal of FT is to improve the circulatory system to avoid the lack of oxygen to organs. Therefore, rapid and early infusion of large volumes of crystalloids is performed in clinical practice to restore blood volume and blood pressure. Despite the relevance of FT in the early management of TBI, there are few clinical trials regarding which solution is better to apply. The aim of this study is to provide a narrative review about the role of the different types of FT used in the daily clinical practice on the management of TBI. To achieve this objective, a physiopathological approach to this entity will be also performed, summarizing why the different types of FT are used.

The Level of Serum Osmolarity at Admission in Prognosis of Nosocomial Mortality in Patients with Severe Brain Trauma

Background

Traumatic brain injury (TBI) is a leading cause of death among patients in developed countries. The patients' prognosis depends on the trauma-induced primary damage as well as the secondary brain damage, including electrolyte disturbances. Therefore, prevention, diagnosis, and timely treatment lead to better prognosis. Herein, the aim is to prognosticate about the mortality in patients with TBI through serum osmolarity at admission.

Materials and Methods

In this cross-sectional study, 141 patients with TBI were assigned through convenience sampling. The level of serum osmolarity was examined once the patients were admitted to emergency department and later, the outcome was recorded. Finally, we analyzed the relationship between osmolarity level and patient outcome in age groups.

Results

The mean serum osmolarity in the age group of under 18 years, 18 to 60 years, and more than 60 years was equal to 295.3 ± 10.02 mOsm/L, 297.2 ± 6.5 mOsm/L, and 301.6 ± 7.6 mOsm/L, respectively (P-value <0.001). Osmolarity with a cut-off point of more than 298.90 and sensitivity and specificity of 70.49 and 62.86, respectively, had appropriate diagnostic value for predicting mortality in these patients (P-value <0.001).

Conclusion

According to the results of this study, serum osmolarity can have an appropriate diagnostic value in predicting mortality in patients with TBI. In addition, in different age categories, the osmolarity serum in the mortality of these patients was significantly different. Therefore, due to the high importance of serum osmolarity in the mortality of patients, careful monitoring of fluid therapy status of trauma patients should be implemented to prevent the development of hyperosmolarity for the patient with irreversible outcomes.

Comparison of Equiosmolar Doses of 7.5% Hypertonic Saline and 20% Mannitol on Cerebral Oxygenation Status and Release of Brain Injury Markers During Supratentorial Craniotomy: A Randomized Controlled Trial

BACKGROUND

Hyperosmolar therapy is the mainstay of treatment to reduce brain bulk and optimize surgical exposure during craniotomy. This study investigated the effect of equiosmolar doses of 7.5% hypertonic saline (HTS) and 20% mannitol on intraoperative cerebral oxygenation and metabolic status, systemic hemodynamics, brain relaxation, markers of cerebral injury, and perioperative craniotomy outcomes.

METHODS

A total of 51 patients undergoing elective supratentorial craniotomy were randomly assigned to receive 7.5% HTS (2 mL/kg) or 20% mannitol (4.6 mL/kg) at scalp incision. Intraoperative arterial and jugular bulb blood samples were collected at predefined time intervals for assessment of various indices of cerebral oxygenation; multiple hemodynamic variables were concomitantly recorded. S100B protein and neuron-specific enolase levels were determined at baseline, and at 6 and 12 hours after surgery for assessment of neuronal injury. Brain relaxation and perioperative outcomes were also assessed.

RESULTS

Demographic and intraoperative data, brain relaxation score, and perioperative outcomes were comparable between groups. Jugular bulb oxygen saturation and partial pressure of oxygen, arterial-jugular oxygen and carbon dioxide differences, and brain oxygen extraction ratio were favorably affected by 7.5% HTS up to 240 minutes postinfusion ( P <0.05), whereas mannitol was associated with only a short-lived (up to 15 min) improvement of these indices ( P <0.05). The changes in cerebral oxygenation corresponded to transient expansion of intravascular volume and improvements of cardiovascular performance. Increases in S100B and neuron-specific enolase levels at 6 and 12 hours after surgery ( P <0.0001) were comparable between groups.

CONCLUSIONS

The conclusion is that 7.5% HTS has a more beneficial effect on cerebral oxygenation than an equiosmolar dose of 20% mannitol during supratentorial craniotomy, yet no clear-cut clinical superiority of either solution could be demonstrated.

Closure intracranial pressure is an objective intraoperative determinant of the adequacy of surgical decompression in traumatic acute subdural haematoma: a multicentre observational study

PURPOSE

Acute subdural haematoma (ASDH) is associated with severe traumatic brain injury and poor outcomes. Although guidelines exist for the decompression of ASDH, the question of adequate decompression remains unanswered. The authors examined the relationship of intracranial pressure (ICP) on closure with outcomes to determine its utility in the determination of adequate ASDH decompression.

METHODS

A multicentre retrospective review of 105 consecutive patients with ASDH who underwent decompressive surgery was performed. Receiver operating characteristic (ROC) analysis with internal validation was performed to determine an ICP threshold for the division of patients into the inadequate and good ICP groups. Multivariable analyses were performed for both inpatient and long-term outcomes.

RESULTS

An ICP threshold of 10 mmHg was identified with a 91.5% specificity, 45.7% sensitivity, and a positive and negative predictive value of 80.8% and 68.4%. There were 26 patients (24.8%) and 79 patients (75.2%) in the inadequate and good ICP groups, respectively. After adjustment, the inadequate ICP group was associated with increased postoperative usage of mannitol (OR 14.2, p < 0.001) and barbiturates (OR 150, p = 0.001). Inadequate ICP was also associated with increased inpatient mortality (OR 24.9, p < 0.001), and a lower rate of favourable MRS at 1 year (OR 0.08, p = 0.008). The complication rate was similar amongst the groups.

CONCLUSIONS

Closure ICP is a novel, objective, and actionable intraoperative biomarker that correlates with inpatient and long-term outcomes in ASDH. Various surgical manoeuvres can be undertaken to achieve this target safely. Large-scale prospective studies should be performed to validate this ICP threshold.

Salted or sweet? Hypertonic saline or mannitol for treatment of intracranial hypertension

PURPOSE OF REVIEW

The aim of this review article is to present current recommendations regarding the use of hypertonic saline and mannitol for the treatment of intracranial hypertension.

RECENT FINDINGS

In recent years, a significant number of studies have been published comparing hypertonic saline with mannitol in patients with acute increased intracranial pressure, mostly caused by traumatic brain injury. Albeit several randomized controlled trials, systematic reviews and meta-analysis support hypertonic saline as more effective than mannitol in reducing intracranial pressure, no clear benefit in regards to the long-term neurologic outcome of these patients has been reported.

SUMMARY

Identifying and treating increased intracranial pressure is imperative in neurocritical care settings and proper management is essential to improve long-term outcomes. Currently, there is insufficient evidence from comparative studies to support a formal recommendation on the use of any specific hyperosmolar medication in patients with acute increased intracranial pressure.

Initial neurocritical care of severe traumatic brain injury: New paradigms and old challenges

Background:

Early neurocritical care aims to ameliorate secondary traumatic brain injury (TBI) and improve neural salvage. Increased engagement of neurosurgeons in neurocritical care is warranted as daily briefings between the intensivist and the neurosurgeon are considered a quality indicator for TBI care. Hence, neurosurgeons should be aware of the latest evidence in the neurocritical care of severe TBI (sTBI).

Methods:

We conducted a narrative literature review of bibliographic databases (PubMed and Scopus) to examine recent research of sTBI.

Results:

This review has several take-away messages. The concept of critical neuroworsening and its possible causes is discussed. Static thresholds of intracranial pressure (ICP) and cerebral perfusion pressure may not be optimal for all patients. The use of dynamic cerebrovascular reactivity indices such as the pressure reactivity index can facilitate individualized treatment decisions. The use of ICP monitoring to tailor treatment of intracranial hypertension (IHT) is not routinely feasible. Different guidelines have been formulated for different scenarios. Accordingly, we propose an integrated algorithm for ICP management in sTBI patients in different resource settings. Although hyperosmolar therapy and decompressive craniectomy are standard treatments for IHT, there is a lack high-quality evidence on how to use them. A discussion of the advantages and disadvantages of invasive ICP monitoring is included in the study. Addition of beta-blocker, anti-seizure, and anticoagulant medications to standardized management protocols (SMPs) should be considered with careful patient selection.

Conclusion:

Despite consolidated research efforts in the refinement of SMPs, there are still many unanswered questions and novel research opportunities for sTBI care.

Prehospital Hypertonic Saline Administration After Severe Traumatic Brain Injury

A 25-year old male paient was critically injuried in a high speed motor vehicle collision over an hour from the nearest trauma center. Paramedics diagnosed the patient with a traumatic brain injury and increasing intracranial pressure and transported the patient to a predesignated landing zone for helicopter intercept. During transport paramedics initiated a severe traumatic brain injury protocol which included the adminisration of 3% hypertonic saline. The flight crew continued 3% hypertonic saline managment which was later transferred to the receiving trauma team. Upon trauma center arrival the patient was diagnosed with a skull fracture and subdural hematoma. The patient was transitioned to a 3% hypertonic saline infusion for the next 24 h. The need for integrating systems of care is particularly important when managing patients with severe traumatic brain injury. This case report describes a patient with a severe TBI who received prehospital 3% hypertonic saline based on an integrated protocol developed between multiple prehosptial systems and a tertiary care trauma center. Severe traumatic brain injuries (TBIs) are a potentially catastrophic event, and morbidity can rise precipitously without early interventions to prevent hypoxia and hypotension and control for rising intracranial pressure. In recent years, hypertonic saline (HTS) has shown efficacy in lowering intracranial pressures for patients experiencing TBIs, the leading cause of death and disability among children and young adults in the United States.¹ Integrating care between health care providers across the acute care continuum, from prehospital systems to discharge, is paramount in providing the best patient outcomes possible, especially in health care system expansions such as air medical transport. The need for integrating systems of care is particularly important when managing patients with severe TBI. Statewide prehospital care protocols vary greatly; 78% provide ventilation guidance, 77.3% have targeted end-tidal carbon dioxide levels below < 35 mm Hg, and only 1 (of 38 reviewed) includes HTS (3%).² One barrier to consistency in protocol development is the available literature. One trial demonstrated that a prehospital bolus of 7.5% HTS in severe TBI did not improve mortality.³ However, the Brain Foundation guidelines continue to recommend the prehospital use of hyperosmolar therapy for patients with severe TBI and evidence of impending herniation.⁴ Hyperosmolar therapy is also recommended as an inpatient strategy for lowering increased intracranial pressure (ICP).⁴ One reason for this apparent disconnect is because the ideal timing of HTS administration and its concentration have not been determined.⁴ A meta-analysis previously determined no one prehospital fluid is superior to another in improving the outcomes of patients with severe TBI.⁵ However, none of the reviewed research investigated the continued use of HTS across an integrated system of care. This case report describes a patient with a severe TBI who received 3% HTS initiated in the prehospital setting with the infusion continued upon arrival at the trauma center using a system-wide integrated protocol.

An overview of systematic reviews on the pharmacological randomized controlled trials for reducing intracranial pressure after traumatic brain injury

BACKGROUND

There is a need for an overview of systematic reviews (SRs) examining randomized clinical trials (RCTs) of pharmacological interventions in the treatment of intracranial pressure (ICP) post-TBI.

OBJECTIVES

To summarize pharmacological effectiveness in decreasing ICP in SRs with RCTs and evaluate study quality.

METHODS

Comprehensive literature searches were conducted in MEDLINE, PubMed, EMBASE, PsycINFO, and Cochrane Library databases for English SRs through October 2020. Inclusion criteria were SRs with RCTs that examined pharmacological interventions to treat ICP in patients post-TBI. Data extracted were participant characteristics, pharmacological interventions, and ICP outcomes. Study quality was assessed with AMSTAR-2.

RESULTS

Eleven SRs between 2003 and 2020 were included. AMSTAR-2 ratings revealed 3/11 SRs of high quality. Pharmacological interventions included hyperosmolars, neuroprotectives, anesthetics, sedatives, and analgesics. Study samples ranged from 7 to 1282 patients. Hyperosmolar agents and sedatives were beneficial in lowering elevated ICP. High bolus dose opioids had a more deleterious effect on ICP. Neuroprotective agents did not show any effects in ICP management. RCT sample sizes and findings in the SRs varied. A lack of detailed data syntheses was noted. AMSTAR-2 analysis revealed moderate-to-high quality in most SRs. Future SRs may focus on streamlined reporting of dosing and clearer clinical recommendations.

CONCLUSIONS

PROSPERO-Registration: CRD42015017355.

Construction and Evaluation of Prognosis Prediction Model for Patients with Brain Contusion and Laceration Based on Machine Learning

Objective

Finding valuable risk factors for the prognosis of brain contusion and laceration can help patients understand the condition and improve the prognosis. This study is aimed at analyzing the risk factors of poor prognosis in patients with brain contusion after the operation.

Methods

A total of 136 patients with cerebral contusion and laceration combined with cerebral hernia treated by neurosurgical craniotomy in our hospital were retrospectively selected and divided into a training set (n = 95) and a test set (n = 41) by the 10-fold crossover method. Logistic regression and back-propagation neural network prediction models were established to predict poor prognosis factors. The receiver operating characteristic curve (ROC) and the calibration curve were used to verify the differentiation and consistency of the prediction model.

Results

Based on logistic regression and back-propagation neural network prediction models, GCS score ≤ 8 on admission, blood loss ≥ 30 ml, mannitol ≥ 2 weeks, anticoagulants before admission, and surgical treatment are the risk factors that affect the poor prognosis of patients with a cerebral contusion after the operation. The area under the ROC was 0.816 (95% CI 0.705~0.926) and 0.819 (95% CI 0.708~0.931), respectively.

Conclusion

The prediction model based on the risk factors that affect the poor prognosis of patients with brain contusion and laceration has good discrimination and accuracy.

Hypertonic lactate for the treatment of intracranial hypertension in patients with acute brain injury

Hypertonic lactate (HL) is emerging as alternative treatment of intracranial hypertension following acute brain injury (ABI), but comparative studies are limited. Here, we examined the effectiveness of HL on main cerebral and systemic physiologic variables, and further compared it to that of standard hypertonic saline (HS). Retrospective cohort analysis of ABI subjects who received sequential osmotherapy with 7.5% HS followed by HL-given at equi-osmolar (2400 mOsmol/L) and isovolumic (1.5 mL/kg) bolus doses-to reduce sustained elevations of ICP (> 20 mmHg). The effect of HL on brain (intracranial pressure [ICP], brain tissue PO₂ [PbtO₂], cerebral microdialysis [CMD] glucose and lactate/pyruvate ratio [LPR]) and blood (chloride, pH) variables was examined at different time-points (30, 60, 90, 120 min vs. baseline), and compared to that of HS. A total of 34 treatments among 17 consecutive subjects (13 traumatic brain injury [TBI], 4 non-TBI) were studied. Both agents significantly reduced ICP (p < 0.001, at all time-points tested): when comparing treatment effectiveness, absolute ICP decrease in mmHg and the duration of treatment effect (median time with ICP < 20 mmHg following osmotherapy 183 [108-257] vs. 150 [111-419] min) did not differ significantly between HL and HS (all p > 0.2). None of the treatment had statistically significant effects on PbtO₂ and CMD biomarkers. Treatment with HL did not cause hyperchloremia and resulted in a more favourable systemic chloride balance than HS (Δ blood chloride - 1 ± 2.5 vs. + 4 ± 3 mmol/L; p < 0.001). This is the first clinical study showing that HL has comparative effectiveness than HS for the treatment of intracranial hypertension, while at the same time avoiding hyperchloremic acidosis. Both agents had no significant effect on cerebral oxygenation and metabolism.

Clinical effects of hypertonic saline boluses in children with severe traumatic brain injury

AIM

To quantify the effects of 3% hypertonic saline (HTS) boluses on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in children.

METHODS

A retrospective study of patients admitted to a regional neurosurgical children's intensive care unit.

RESULTS

A total of 156 HTS boluses were given to children with traumatic brain injury. ICP decreased 6 mmHg (P < 0.01) and CPP increased 4 mmHg (P = 0.003) 1-h post-bolus. Effects persisted for 3 h post-dose ICP was 5 mmHg lower) and 4 h post-bolus CPP was 3 mmHg higher. ICP change was not associated with pre-bolus serum sodium concentration.

CONCLUSIONS

Hypertonic saline 3% at 5 mL/kg is an effective osmolar therapy for reducing ICP and increasing CPP in children for up to 3 h. '53-53' is a suitable guide - 5 mL/kg of 3% HTS will on average decrease ICP by at least 5 mmHg for 3 h. Pre-bolus serum sodium concentration is not correlated with effect size.

Hypertonic Saline Compared to Mannitol for the Management of Elevated Intracranial Pressure in Traumatic Brain Injury: A Meta-Analysis

Background: We performed a meta-analysis to evaluate the effect of hypertonic saline compared to mannitol for the management of elevated intracranial pressure in traumatic brain injury.

Methods: A systematic literature search up to July 2021 was performed and 17 studies included 1,392 subjects with traumatic brain injury at the start of the study; 708 of them were administered hypertonic saline and 684 were given mannitol. They were reporting relationships between the effects of hypertonic saline compared to mannitol for the management of elevated intracranial pressure in traumatic brain injury. We calculated the odds ratio (OR) and mean difference (MD) with 95% confidence intervals (CIs) to assess the effect of hypertonic saline compared to mannitol for the management of elevated intracranial pressure in traumatic brain injury using the dichotomous or continuous method with a random or fixed-effect model.

Results: Hypertonic saline had significantly lower treatment failure (OR, 0.38; 95% CI, 0.15–0.98, p = 0.04), lower intracranial pressure 30–60 mins after infusion termination (MD, −1.12; 95% CI, −2.11 to −0.12, p = 0.03), and higher cerebral perfusion pressure 30–60 mins after infusion termination (MD, 5.25; 95% CI, 3.59–6.91, p &lt; 0.001) compared to mannitol in subjects with traumatic brain injury.

However, hypertonic saline had no significant effect on favorable outcome (OR, 1.61; 95% CI, 1.01–2.58, p = 0.05), mortality (OR, 0.59; 95% CI, 0.34–1.02, p = 0.06), intracranial pressure 90–120 mins after infusion termination (MD, −0.90; 95% CI, −3.21–1.41, p = 0.45), cerebral perfusion pressure 90–120 mins after infusion termination (MD, 4.28; 95% CI, −0.16–8.72, p = 0.06), and duration of elevated intracranial pressure per day (MD, 2.20; 95% CI, −5.44–1.05, p = 0.18) compared to mannitol in subjects with traumatic brain injury.

Conclusions: Hypertonic saline had significantly lower treatment failure, lower intracranial pressure 30–60 mins after infusion termination, and higher cerebral perfusion pressure 30–60 mins after infusion termination compared to mannitol in subjects with traumatic brain injury. However, hypertonic saline had no significant effect on the favorable outcome, mortality, intracranial pressure 90–120 mins after infusion termination, cerebral perfusion pressure 90–120 mins after infusion termination, and duration of elevated intracranial pressure per day compared to mannitol in subjects with traumatic brain injury. Further studies are required to validate these findings.

Moderate and Severe Traumatic Brain Injury

PURPOSE OF REVIEW

Traumatic brain injury (TBI) encompasses a group of heterogeneous manifestations of a disease process with high neurologic morbidity and, for severe TBI, high probability of mortality and poor neurologic outcomes. This article reviews TBI in neurocritical care, hence focusing on moderate and severe TBI, and includes an up-to-date review of the many variables to be considered in clinical care.

RECENT FINDINGS

With advances in medicine and biotechnology, understanding of the impact of TBI has substantially elucidated the distinction between primary and secondary brain injury. Consequently, care of TBI is evolving, with intervention-based modalities targeting multiple physiologic variables. Multimodality monitoring to assess intracranial pressure, cerebral oxygenation, cerebral metabolism, cerebral blood flow, and autoregulation is at the forefront of such advances.

SUMMARY

Understanding the anatomic and physiologic principles of acute brain injury is necessary in managing moderate to severe TBI. Management is based on the prevention of secondary brain injury from resultant trauma. Care of patients with TBI should occur in a dedicated critical care unit with subspecialty expertise. With the advent of multimodality monitoring and targeted biomarkers in TBI, patient outcomes have a higher probability of improving in the future.

Multidisciplinary management of a traumatic posterior meningeal artery pseudoaneurysm: A case report and review of the literature

Background

Meningeal arterial injuries represent <1% of all blunt traumatic brain injuries (TBIs). Middle meningeal artery (MMA) lesions comprise the majority. However, there is little clinical data on posterior meningeal artery (PMA) injuries.

Case report

A 69-year-old man was brought to our trauma center after sustaining a fall inside a warehouse. He was GCS (Glasgow Coma Scale) 3 on arrival. Non-contrast CT (computed tomography) brain showed subarachnoid hemorrhage with diffuse cerebral edema and a basilar skull fracture. The patient subsequently underwent emergency ventriculostomy. Immediately after the procedure, further imaging with CTA (computed tomography angiography) head identified a hyperintense posterior cranial fossa lesion, prompting cerebral angiography with identification and embolization of a traumatic PMA pseudoaneurysm. The patient improved and was discharged to a long-term acute care facility. At 3 months post-discharge, the patient was eating, talking with family, and working aggressively with physical therapy.

Discussion

This case represents a functional neurologic outcome from a rare subset of TBI. Early CTA head imaging is not supported by limited literature, but allowed for expedient identification and definitive management of this PMA pseudoaneurysm. In the critical care setting, hyperosmolar therapy, CSF (cerebrospinal fluid) drainage, prompt enteral nutritional support, and early tracheostomy all represent evolving evidence-based strategies to optimize care for severe TBI.

Conclusions

The initial evaluation and management of severe TBI can be nuanced. Future research may refine indications for CTA head to the diagnostic evaluation of patients with both severe TBI and skull fractures.

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Traumatic intracerebral hemorrhage caused by meningeal artery injuries are rare, and usually involve the middle meningeal artery; lesions of the posterior meningeal artery remain even more obscure

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Severe traumatic brain injury (TBI) associated with basilar skull fractures represents a pattern of injury for which CT angiography of the head can be useful in identifying meningeal vascular injuries

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Critical care for severe TBI involves preventing secondary insult to cerebral tissue; strategies continue to evolve with hyperosmolar therapy, CSF drainage, prompt enteral nutritional support, and early tracheostomy

Lidocaine coinfusion alleviates vascular pain induced by hypertonic saline infusion: a randomized, placebo-controlled trial

Background

Hypertonic saline solution has been frequently utilized in clinical practice. However, due to the nonphysiological osmolality, hypertonic saline infusion usually induces local vascular pain. We conducted this study to evaluate the effect of lidocaine coinfusion for alleviating vascular pain induced by hypertonic saline.

Methods

One hundred and six patients undergoing hypertonic saline volume preloading prior to spinal anesthesia were randomly allocated to two groups of 53 each. Group L received a 1 mg/kg lidocaine bolus followed by infusion of 2 mg/kg/h through the same IV line during hypertonic saline infusion; Group C received a bolus and infusion of normal saline of equivalent volume. Visual analogue scale (VAS) scores of vascular pain were recorded every 4 min.

Results

The vascular pain severity in Group L was significantly lower than that in Group C for each time slot (P < 0.05). The overall incidence of vascular pain during hypertonic saline infusion in Group L was 48.0%, which was significantly lower than the incidence (79.6%) in Group C (P < 0.05).

Conclusion

Lidocaine coinfusion could effectively alleviate vascular pain induced by hypertonic saline infusion.

Trial registration

Chinese Clinical Trial Registry, number: ChiCTR1900023753. Registered on 10 June 2019.

Brain Herniation and Intracranial Hypertension

This article introduces the basic concepts of intracranial physiology and pressure dynamics. It also includes discussion of signs and symptoms and examination and radiographic findings of patients with acute cerebral herniation as a result of increased as well as decreased intracranial pressure. Current best practices regarding medical and surgical treatments and approaches to management of intracranial hypertension as well as future directions are reviewed. Lastly, there is discussion of some of the implications of critical medical illness (sepsis, liver failure, and renal failure) and treatments thereof on causation or worsening of cerebral edema, intracranial hypertension, and cerebral herniation.

Neuroanesthesiology Update

This review summarizes the literature published in 2020 that is relevant to the perioperative care of neurosurgical patients and patients with neurological diseases as well as critically ill patients with neurological diseases. Broad topics include general perioperative neuroscientific considerations, stroke, traumatic brain injury, monitoring, anesthetic neurotoxicity, and perioperative disorders of cognitive function.

23.4% Sodium Chloride Versus Mannitol for the Reduction of Intracranial Pressure in Patients With Traumatic Brain Injury: A Single-Center Retrospective Cohort Study

BACKGROUND

Intermittent doses of mannitol or hypertonic saline are recommended to treat elevated intracranial pressure (ICP). However, it is unclear if one agent is more effective than the other. Previous studies have compared mannitol and hypertonic saline in reduction of ICP, with conflicting results. However, no study thus far has compared 23.4% sodium chloride with mannitol.

OBJECTIVE

The objective of this study was to determine the difference in absolute reduction of ICP 60 minutes after infusion of 23.4% sodium chloride versus mannitol.

METHODS

This was a single-center retrospective cohort study that included patients at least 16 years old admitted to the trauma/surgical intensive care unit between August 8, 2016, and August 30, 2018, who received either 23.4% sodium chloride 30 mL and/or mannitol 0.5 g/kg and had an ICP monitor or external ventricular drain in place. The primary outcome was absolute reduction in ICP 60 minutes after infusion of hyperosmolar therapy.

RESULTS

In all, 31 patients and 162 doses of hyperosmolar therapy were included in the analysis. There was no statistically significant difference in the primary end point of absolute reduction of ICP 60 minutes after infusion of hyperosmolar therapy comparing 23.4% sodium chloride 30 mL with 0.5 g/kg mannitol (P = 0.2929). There was no statistically significant difference found for any secondary end points.

CONCLUSION AND RELEVANCE

No difference was found for absolute reduction of ICP at 30, 60, and 120 minutes, respectively, after infusion of hyperosmolar agent or time to next elevated ICP. Patient-specific parameters should be used to guide the choice of hyperosmolar agent to be administered.

Immunomodulatory Effect of Hypertonic Saline Solution in Traumatic Brain-Injured Patients and Intracranial Hypertension

Traumatic brain injury (TBI) is often associated with an increase in the intracranial pressure (ICP). This increase in ICP can cross the physiological range and lead to a reduction in cerebral perfusion pressure (CPP) and the resultant cerebral blood flow (CBF). It is this reduction in the CBF that leads to the secondary damage to the neural parenchyma along with the physical axonal and neuronal damage caused by the mass effect. In certain cases, a surgical intervention may be required to either remove the mass lesion (hematoma of contusion evacuation) or provide more space to the insulted brain to expand (decompressive craniectomy). Whether or not a surgical intervention is performed, all these patients require some form of pharmaceutical antiedema agents to bring down the raised ICP. These agents have been broadly classified as colloids (e.g., mannitol, glycerol, urea) and crystalloids (e.g., hypertonic saline), and have been used since decades. Even though mannitol has been the workhorse for ICP reduction owing to its unique properties, crystalloids have been found to be the preferred agents, especially when long-term use is warranted. The safest and most widely used agent is hypertonic saline in various concentrations. Whatever be the concentration, hypertonic saline has created special interest among physicians owing to its additional property of immunomodulation and neuroprotection. In this review, we summarize and understand the various mechanism by which hypertonic saline exerts its immunomodulatory effects that helps in neuroprotection after TBI.

Equimolar doses of hypertonic agents (saline or mannitol) in the treatment of intracranial hypertension after severe traumatic brain injury

BACKGROUND

Mannitol and hypertonic saline (HTS) are effective in reducing intracranial pressure (ICP) after severe traumatic brain injury (TBI). However, their efficacy on the ICP has not been evaluated rigorously.

OBJECTIVE

To evaluate the efficacy of repeated bolus dosing of HTS and mannitol in similar osmotic burdens to treat intracranial hypertension (ICH) in patients with severe TBI.

METHODS

The authors used an alternating treatment protocol to evaluate the efficacy of HTS with that of mannitol given for ICH episodes in patients treated for severe TBI at their hospital during 2017 to 2019. Doses of similar osmotic burdens (20% mannitol, 2 ml/kg, or 10% HTS, 0.63 ml/kg, administered as a bolus via a central venous catheter, infused over 15 minutes) were given alternately to the individual patient with severe TBI during ICH episodes. The choice of osmotic agents for the treatment of the initial ICH episode was determined on a randomized basis; osmotic agents were alternated for every subsequent ICH episode in each individual patient. intracranial pressure (ICP), mean arterial pressure (MAP), and cerebral perfusion pressure (CPP) were continuously monitored between the beginning of each osmotherapy and the return of ICP to 20 mm Hg. The duration of the effect of ICP reduction (between the beginning of osmotherapy and the return of ICP to 20 mm Hg), the maximum reduction of ICP and its time was recorded after each dose. Serum sodium and plasma osmolality were measured before, 0.5 hours and 3 hours after each dose. Adverse effects such as central pontine myelinolysis (CPM), severe fluctuations of serum sodium and plasma osmolality were assessed to evaluate the safety of repeated dosing of HTS and mannitol.

RESULTS

Eighty three patients with severe TBI were assessed, including 437 ICH episodes, receiving 236 doses of HTS and 221 doses of mannitol totally. There was no significant difference between equimolar HTS and mannitol boluses on the magnitude of ICP reduction, the duration of effect, and the time to lowest ICP achieved (P > .05). The proportion of efficacious boluses was higher for HTS than for mannitol (P = .016), as was the increase in serum sodium (P = .038). The serum osmolality increased immediately after osmotherapy with a significant difference (P = .017). No cases of CPM were detected.

CONCLUSION

Repeat bolus dosing of 10% HTS and 20% mannitol appears to be significantly and similarly effective for treating ICH in patients with severe TBI. The proportion of efficacious doses of HTS on ICP reduction may be higher than mannitol.

Management and Challenges of Severe Traumatic Brain Injury

Traumatic brain injury (TBI) is the leading cause of death and disability in trauma patients, and can be classified into mild, moderate, and severe by the Glasgow coma scale (GCS). Prehospital, initial emergency department, and subsequent intensive care unit (ICU) management of severe TBI should focus on avoiding secondary brain injury from hypotension and hypoxia, with appropriate reversal of anticoagulation and surgical evacuation of mass lesions as indicated. Utilizing principles based on the Monro-Kellie doctrine and cerebral perfusion pressure (CPP), a surrogate for cerebral blood flow (CBF) should be maintained by optimizing mean arterial pressure (MAP), through fluids and vasopressors, and/or decreasing intracranial pressure (ICP), through bedside maneuvers, sedation, hyperosmolar therapy, cerebrospinal fluid (CSF) drainage, and, in refractory cases, barbiturate coma or decompressive craniectomy (DC). While controversial, direct ICP monitoring, in conjunction with clinical examination and imaging as indicated, should help guide severe TBI therapy, although new modalities, such as brain tissue oxygen (PbtO₂) monitoring, show great promise in providing strategies to optimize CBF. Optimization of the acute care of severe TBI should include recognition and treatment of paroxysmal sympathetic hyperactivity (PSH), early seizure prophylaxis, venous thromboembolism (VTE) prophylaxis, and nutrition optimization. Despite this, severe TBI remains a devastating injury and palliative care principles should be applied early. To better affect the challenging long-term outcomes of severe TBI, more and continued high quality research is required.

Effects of hypertonic saline versus mannitol in patients with traumatic brain injury in prehospital, emergency department, and intensive care unit settings: a systematic review and meta-analysis

BACKGROUND

Intracranial pressure control has long been recognized as an important requirement for patients with severe traumatic brain injury. Hypertonic saline has drawn attention as an alternative to mannitol in this setting. The aim of this study was to assess the effects of hypertonic saline versus mannitol on clinical outcomes in patients with traumatic brain injury in prehospital, emergency department, and intensive care unit settings by systematically reviewing the literature and synthesizing the evidence from randomized controlled trials.

METHODS

We searched the MEDLINE database, the Cochrane Central Register of Controlled Trials, and the Igaku Chuo Zasshi (ICHUSHI) Web database with no date restrictions. We selected randomized controlled trials in which the clinical outcomes of adult patients with traumatic brain injury were compared between hypertonic saline and mannitol strategies. Two investigators independently screened the search results and conducted the data extraction. The primary outcome was all-cause mortality. The secondary outcomes were 90-day and 180-day mortality, good neurological outcomes, reduction in intracranial pressure, and serum sodium level. Random effects estimators with weights calculated by the inverse variance method were used to determine the pooled risk ratios.

RESULTS

A total of 125 patients from four randomized trials were included, and all the studies were conducted in the intensive care unit. Among 105 patients from three trials that evaluated the primary outcome, 50 patients were assigned to the hypertonic saline group and 55 patients were assigned to the mannitol group. During the observation period, death was observed for 16 patients in the hypertonic saline group (32.0%) and 21 patients in the mannitol group (38.2%). The risks were not significant between the two infusion strategies (pooled risk ratio, 0.82; 95% confidence interval, 0.49-1.37). There were also no significant differences between the two groups in the other secondary outcomes. However, the certainty of the evidence was rated very low for all outcomes.

CONCLUSIONS

Our findings revealed no significant difference in the all-cause mortality rates between patients receiving hypertonic saline or mannitol to control intracranial pressure. Further investigation is warranted because we only included a limited number of studies.

Hyperosmolar Treatment for Patients at Risk for Increased Intracranial Pressure: A Single-Center Cohort Study

Treatment with osmoactive agents such as mannitol or hypertonic saline (HTS) solutions is widely used to manage or prevent the increase of intracranial pressure (ICP) in central nervous system (CNS) disorders. We sought to evaluate the variability and mean plasma concentrations of the water and electrolyte balance parameters in critically ill patients treated with osmotic therapy and their influence on mortality. This cohort study covered patients hospitalized in an intensive care unit (ICU) from January 2017 to June 2019 with presumed increased ICP or considered to be at risk of it, treated with 15% mannitol (G1, n = 27), a combination of 15% mannitol and 10% hypertonic saline (HTS) (G2, n = 33) or 10% HTS only (G3, n = 13). Coefficients of variation (Cv) and arithmetic means (mean) were calculated for the parameters reflecting the water and electrolyte balance, i.e., sodium (NaCv/NaMean), chloride (ClCv/ClMean) and osmolality (mOsmCv/mOsmMean). In-hospital mortality was also analyzed. The study group comprised 73 individuals (36 men, 49%). Mortality was 67% (n = 49). Median NaCv (G1: p = 0.002, G3: p = 0.03), ClCv (G1: p = 0.02, G3: p = 0.04) and mOsmCv (G1: p = 0.001, G3: p = 0.02) were higher in deceased patients. NaMean (p = 0.004), ClMean (p = 0.04), mOsmMean (p = 0.003) were higher in deceased patients in G3. In G1: NaCv (AUC = 0.929, p < 0.0001), ClCv (AUC = 0.817, p = 0.0005), mOsmCv (AUC = 0.937, p < 0.0001) and in G3: NaMean (AUC = 0.976, p < 0.001), mOsmCv (AUC = 0.881, p = 0.002), mOsmMean (AUC = 1.00, p < 0.001) were the best predictors of mortality. The overall mortality prediction for combined G1+G2+G3 was very good, with AUC = 0.886 (p = 0.0002). The mortality of critically ill patients treated with osmotic agents is high. Electrolyte disequilibrium is the independent predictor of mortality regardless of the treatment method used. Variations of plasma sodium, chloride and osmolality are the most deleterious factors regardless of the absolute values of these parameters.

Guidelines for the Acute Treatment of Cerebral Edema in Neurocritical Care Patients

BACKGROUND

Acute treatment of cerebral edema and elevated intracranial pressure is a common issue in patients with neurological injury. Practical recommendations regarding selection and monitoring of therapies for initial management of cerebral edema for optimal efficacy and safety are generally lacking. This guideline evaluates the role of hyperosmolar agents (mannitol, HTS), corticosteroids, and selected non-pharmacologic therapies in the acute treatment of cerebral edema. Clinicians must be able to select appropriate therapies for initial cerebral edema management based on available evidence while balancing efficacy and safety.

METHODS

The Neurocritical Care Society recruited experts in neurocritical care, nursing, and pharmacy to create a panel in 2017. The group generated 16 clinical questions related to initial management of cerebral edema in various neurological insults using the PICO format. A research librarian executed a comprehensive literature search through July 2018. The panel screened the identified articles for inclusion related to each specific PICO question and abstracted necessary information for pertinent publications. The panel used GRADE methodology to categorize the quality of evidence as high, moderate, low, or very low based on their confidence that the findings of each publication approximate the true effect of the therapy.

RESULTS

The panel generated recommendations regarding initial management of cerebral edema in neurocritical care patients with subarachnoid hemorrhage, traumatic brain injury, acute ischemic stroke, intracerebral hemorrhage, bacterial meningitis, and hepatic encephalopathy.

CONCLUSION

The available evidence suggests hyperosmolar therapy may be helpful in reducing ICP elevations or cerebral edema in patients with SAH, TBI, AIS, ICH, and HE, although neurological outcomes do not appear to be affected. Corticosteroids appear to be helpful in reducing cerebral edema in patients with bacterial meningitis, but not ICH. Differences in therapeutic response and safety may exist between HTS and mannitol. The use of these agents in these critical clinical situations merits close monitoring for adverse effects. There is a dire need for high-quality research to better inform clinicians of the best options for individualized care of patients with cerebral edema.

Effect of mannitol plus hypertonic saline combination versus hypertonic saline monotherapy on acute kidney injury after traumatic brain injury

PURPOSE

To compare the effect of mannitol plus hypertonic saline combination (MHS) versus hypertonic saline monotherapy (HS) on renal function in patients with traumatic brain injury (TBI).

MATERIALS AND METHODS

This was a secondary analysis of data from the Resuscitation Outcomes Consortium Hypertonic Saline Trial Shock Study and Traumatic Brain Injury Study. The study cohort included a propensity matched subset of patients with TBI who received MHS or HS. The primary outcome measure was the maximum serum creatinine value during critical illness.

RESULTS

The cohort consisted of 163 patients in the MHS group and 163 patients in the HS group (n = 326). The maximum serum creatinine value during hospitalization was 82 ± 47 μmol/L (0.86 ± 0.26 mg/dL) in the MHS group and 76 ± 23 μmol/L (0.92 ± 0.53 mg/dL) in the HS group (difference -6 μmol/L, 95% CI -14 to 2 μmol/L, p = .151). The lowest eGFR during hospitalization was 108 ± 25 mL/min in the MHS group and 112 ± 24 mL/min in the HS group (difference -4 mL/min, 95% CI -1 to 9 mLmin, p = .150).

CONCLUSIONS

The addition of mannitol to HS did not increase the risk of renal dysfunction compared to HS alone in patients with TBI.

Cerebral Edema in Traumatic Brain Injury: a Historical Framework for Current Therapy

PURPOSE OF REVIEW

The purposes of this narrative review are to (1) summarize a contemporary view of cerebral edema pathophysiology, (2) present a synopsis of current management strategies in the context of their historical roots (many of which date back multiple centuries), and (3) discuss contributions of key molecular pathways to overlapping edema endophenotypes. This may facilitate identification of important therapeutic targets.

RECENT FINDINGS

Cerebral edema and resultant intracranial hypertension are major contributors to morbidity and mortality following traumatic brain injury. Although Starling forces are physical drivers of edema based on differences in intravascular vs extracellular hydrostatic and oncotic pressures, the molecular pathophysiology underlying cerebral edema is complex and remains incompletely understood. Current management protocols are guided by intracranial pressure measurements, an imperfect proxy for cerebral edema. These include decompressive craniectomy, external ventricular drainage, hyperosmolar therapy, hypothermia, and sedation. Results of contemporary clinical trials assessing these treatments are summarized, with an emphasis on the gap between intermediate measures of edema and meaningful clinical outcomes. This is followed by a brief statement summarizing the most recent guidelines from the Brain Trauma Foundation (4th edition). While many molecular mechanisms and networks contributing to cerebral edema after TBI are still being elucidated, we highlight some promising molecular mechanism-based targets based on recent research including SUR1-TRPM4, NKCC1, AQP4, and AVP1.

SUMMARY

This review outlines the origins of our understanding of cerebral edema, chronicles the history behind many current treatment approaches, and discusses promising molecular mechanism-based targeted treatments.

Formulating a Stable Mannitol Infusion while Maintaining Hyperosmolarity

Mannitol infusion is commonly used in the treatment of intracranial hypertension following traumatic brain injury. It has long been known to have stability issues, specifically, mannitol recrystallises from solutions greater than 10% w/v in ambient conditions. This can happen at any time, whether on the pharmacy shelf or during a medical procedure. This study describes the stability limits of 20% w/v mannitol infusion (the most common strength used clinically) and proposes a number of safer, stable and tuneable hyperosmotic formulations of mannitol in combination with clinically acceptable osmotic agents (NaCl, sorbitol and glycerol).