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

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.

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.

The impact of brain tissue oxygenation monitoring on the Glasgow Outcome Scale/Glasgow Outcome Scale Extended in patients with moderate to severe traumatic brain injury: A systematic review

BACKGROUND

Traumatic brain injuries (TBIs) are one of the leading causes of death or long-term disability around the world. As a result of improvements in supportive care, patients are surviving more severe insults with more pronounced dependency on their families, hospitals, and long-term care facilities. The introduction of brain tissue oxygenation (PbtO2) monitoring aims to recognize episodes of reduced cerebral perfusion with and without associated increased intracranial pressure (ICP).

AIM

The aim of this review is to determine the impact of PbtO2 on the Glasgow Outcome Scale/Glasgow Outcome Scale Extended (GOS/GOSE) in patients with moderate to severe TBI.

DESIGN

Systematic review with narrative and meta-analysis. All original research in which adult patients undergoing PbtO2 were compared with a control group of traditional ICP/cerebral perfusion pressure (CPP) monitoring. Both randomized controlled trials and observational studies were included in this review.

METHODS

Databases were searched in September 2022. The primary outcome of the review was the impact of PbtO2 monitoring on GOS/GOSE, while secondary outcomes were mortality and length of stay (LOS) in the intensive care unit (ICU).

RESULTS

Seven studies with a combined number of 770 patients were included in the review. These patients were adults ≥16 years of age. Only two of the studies included found a statistically significant association between PbtO2 monitoring and improved long-term neurological outcomes in patients with TBI (p = .01, p < .01). A meta-analysis of the secondary outcomes identified an associated reduction of mortality in favour of the group treated with PbtO2 monitoring (p < .0001). Results from studies examining LOS in ICU have demonstrated an associated increase of LOS in ICU in patients treated with PbtO2-guided therapy.

CONCLUSION

From the studies included in this review, only two found a statistically significant association between PbtO2 monitoring and long-term outcomes. It is unclear whether PbtO2 goal-directed therapy has a positive impact on the long-term neurological functions and mortality of patients suffering from TBI. A multicentre randomized controlled trial may provide further evidence, but not necessarily conclusive.

RELEVANCE TO CLINICAL PRACTICE

Further research is warranted to determine the efficacy of the introduction of this new monitoring system to guide local policy change.

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.

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.

Comparison of different concentrations of hypertonic saline in patients with traumatic brain injury: Evidence from direct and indirect comparisons

BACKGROUND

Until now, it has remained difficult for doctors to make an informative decision as to which concentration of hypertonic saline (HTS) is more beneficial for patients with traumatic brain injury (TBI). We therefore investigate the effect of different concentrations of hypertonic saline on mortality and ICP lowering efficacy in this group of patients.

METHODS

Several databases including Ovid MEDLINE, Ovid EMBASE, PubMed, and Cochrane Central Register of Controlled Trials were searched comprehensively from inception to February 28, 2022. We only included RCTs that compared HTS with different concentrations and mannitol in adult patients with TBI. The main outcome was mortality from any cause. We reported relative risks (RR) and 95% confidence intervals (CIs) from direct meta-analysis and 95% credible intervals (CrIs) from network meta-analysis.

RESULTS

Overall, 13 trials containing 593 patients were included in this study. Direct analysis revealed that HTS was associated with decreased risk of all-cause mortality (RR, 1.29; 95% CI: 1.08 to 1.54). In the network meta-analysis, 5% HTS was associated with a significant decrease in all-cause mortality compared with mannitol (RR 0.34, 95% CrI: 0.14 to 0.72). We also found 7.5% HTS was associated with a significant increase in all-cause mortality compared with 5% HTS (RR, 2.87; 95% CrI: 1.00 to 8.99).

CONCLUSIONS

Among patients with TBI, the application of 5% HTS was associated with decreased all-cause mortality compared with mannitol and other concentration. Treatments with 10% and 15% HTS was more likely to decrease ICP compared with other fluids. More trials are needed to verify the current findings.

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.

The Optimal Dose and Concentration of Hypertonic Saline in Traumatic Brain Injury - A Systematic Review

Management of increased intracranial pressure in traumatic brain injury remains challenging in neurosurgical emergencies. The mainstay of medical management for increased intracranial pressure is hyperosmolar therapy with mannitol or hypertonic saline. Mannitol has been the “gold standard” osmotic agent for almost a century. Given its wide usage, there has been a dilemma of concern because of its adverse effects. Over the past few decades, hypertonic saline has become an increasingly better alternative. To date, there is no consensus on the optimal therapeutic dose and concentration of hypertonic saline for treating increased intracranial pressure. This systematic review aimed to compare the efficacy of hypertonic saline and mannitol in the management of traumatic brain injury and investigate the optimal dose and concentration of hypertonic saline for the treatment. Extensive research was conducted on PubMed, DOAJ, and Cochrane databases. Studies published within the last 20 years were included. Research articles in the form of meta-analyses, clinical trials, and randomized controlled trials were preferred. Those with ambiguous remarks, irrelevant correlations to the main issue, or a focus on other disorders were excluded. Nineteen studies were included in the systematic review. Eleven studies have stated that hypertonic saline and mannitol were equally efficacious, whereas eight studies have reported that hypertonic saline was superior. Moreover, 3% hypertonic saline was the main concentration most discussed in research. Improvements in increased intracranial pressure, cerebral perfusion pressure, survival rate, brain relaxation, and systemic hemodynamics were observed. Hypertonic saline is worthy of consideration as an excellent alternative to mannitol. This study suggests 3% hypertonic saline as the optimal concentration, with the therapeutic dose from 1.4 to 2.5 mL/kg, given as a bolus.

Evaluation of cerebral hemodynamics by transcranial Doppler ultrasonography and its correlation with intracranial pressure in an animal model of intracranial hypertension

BACKGROUND

Transcranial Doppler has been tested in the evaluation of cerebral hemodynamics as a non-invasive assessment of intracranial pressure (ICP), but there is controversy in the literature about its actual benefit and usefulness in this situation.

OBJECTIVE

To investigate cerebral blood flow assessed by Doppler technique and correlate with the variations of the ICP in the acute phase of intracranial hypertension in an animal model.

METHODS

An experimental animal model of intracranial hypertension was used. The experiment consisted of two groups of animals in which intracranial balloons were implanted and inflated with 4 mL (A) and 7 mL (B) for controlled simulation of different volumes of hematoma. The values of ICP and Doppler parameters (systolic [FVs], diastolic [FVd], and mean [FVm] cerebral blood flow velocities and pulsatility index [PI]) were collected during the entire procedure (before and during hematoma simulations and venous hypertonic saline infusion intervention). Comparisons between Doppler parameters and ICP monitoring were performed.

RESULTS

Twenty pigs were studied, 10 in group A and 10 in group B. A significant correlation between PI and ICP was obtained, especially shortly after abrupt elevation of ICP. There was no correlation between ICP and FVs, FVd or FVm separately. There was also no significant change in ICP after intravenous infusion of hypertonic saline solution.

CONCLUSIONS

These results demonstrate the potential of PI as a parameter for the evaluation of patients with suspected ICP elevation.

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.

Salt: The paradoxical philosopher's stone of autonomic medicine

Sodium chloride, or common table salt, for millennia has played a prominent role in human affairs. Salt is also a key molecule for regulating intravascular fluid volume in patients with orthostatic disorders. In this first article of a special issue of the journal focusing on salt and the autonomic nervous system, the historical and physiologic significance of salt is reviewed, highlighting its importance to society and to medicine. The relevance of salt both for civilization and for autonomic physiology penetrates into nearly every aspect of life and health. Replacing salt that has been depleted or administering salt to expand intravascular volume is considered standard treatment for patients with orthostatic hypotension and syndromes of orthostatic intolerance. The potential longterm effects of added salt, including effects unrelated to intravascular volume, have been insufficiently studied in patients with autonomic disorders. A salient concern is the potential increased risk of developing hypertension. Underappreciated aspects of salt include its ability to increase anxiety and through nonosmotic mechanisms to contribute to local tissue inflammation. Salt may be either salubrious or detrimental, or possibly both at the same time, depending on the clinical conditions. Reconciling these opposite effects in clinical practice requires weighing benefits against potential risks, assessing what is known alongside what is uncertain, and titrating treatment decisions to the particular needs of each individual patient.

Potentially Detrimental Effects of Hyperosmolality in Patients Treated for Traumatic Brain Injury

Hyperosmotic therapy is commonly used to treat intracranial hypertension in traumatic brain injury patients. Unfortunately, hyperosmolality also affects other organs. An increase in plasma osmolality may impair kidney, cardiac, and immune function, and increase blood-brain barrier permeability. These effects are related not only to the type of hyperosmotic agents, but also to the level of hyperosmolality. The commonly recommended osmolality of 320 mOsm/kg H2O seems to be the maximum level, although an increase in plasma osmolality above 310 mOsm/kg H2O may already induce cardiac and immune system disorders. The present review focuses on the adverse effects of hyperosmolality on the function of various organs.

Traumatic Brain Injury-A Review of Intravenous Fluid Therapy

This manuscript will review intravenous fluid therapy in traumatic brain injury. Both human and animal literature will be included. Basic treatment recommendations will also be discussed.

Effects of two different doses of 3% hypertonic saline with mannitol during decompressive craniectomy following traumatic brain injury: A prospective, controlled study

Background and Aims:

The current study was designed to compare the effects of two different doses of 3% hypertonic saline with mannitol on intraoperative events during decompressive craniectomy in traumatic brain injury (TBI). Primary outcome measures included assessment of intraoperative brain relaxation, hemodynamic variables, and serum electrolytes. Effect on the postoperative outcome, in terms of the Glasgow coma scale (GCS), length of stay in the ICU, and mortality were the secondary outcome measures.

Material and Methods:

Ninety patients with TBI undergoing craniotomy were enrolled. Patients were assigned to receive 300 mL (328 mOsm) of mannitol (n = 26, M) only or 300 mL of mannitol with 150 mL (482 mOsm) of 3% HS (n = 35, HS₁) or with 300 mL (636 mOsm) of 3% HS (n = 29, HS₂). Brain relaxation was assessed and if required, a rescue dose of mannitol (150 mL) was given. GCS was assessed preoperatively, 24 h postoperatively, and at the time of discharge from the ICU and total duration of stay was noted.

Results:

Acceptable brain relaxation was observed in 89.66% (n = 26, HS₂) and 80% (n = 28, HS₁) patients as compared to 46.1% (n = 12, M) patients (P < 0.001) with significantly less number of patients requiring rescue doses of mannitol in groups HS₁ and HS₂(n = 7 and 3, respectively) as compared to group M (n = 14) (P < 0.05). There was a significant improvement in GCS at 24 h and at the time of discharge from the ICU in patients with a severe head injury in group HS₂ (P = 0.029). In patients with moderate head injury there was a significant improvement in GCS at the time of discharge among all the three groups (P < 0.05).

Conclusion:

Increasing osmotic load by addition of 3% HS to mannitol provides better intraoperative brain relaxation than mannitol alone during decompressive craniectomy. An addition of 300mL 3% HS was found to be more effective in improving GCS in patients with severe TBI.