Use of hypertonic saline solutions in treatment of cerebral edema and intracranial hypertension

Comparison of 20% mannitol and 3% hypertonic saline on intracranial pressure and systemic hemodynamics

Mannitol and hypertonic saline (HS) are most commonly used hyperosmotic agents for intraoperative brain relaxation. We compared the changes in ICP and systemic hemodynamics after infusion of equiosmolar solutions of both agents in patients undergoing craniotomy for supratentorial tumors. Forty enrolled adults underwent a standard anesthetic induction. Apart from routine monitoring parameters, subdural ICP with Codmann catheter and cardiac indices by Vigileo monitor, were recorded. The patients were randomized to receive equiosmolar solutions of either 20% mannitol (5ml/kg) or 3% HS (5.35ml/kg) for brain relaxation. The time of placement of ICP catheter was marked as T₀ and baseline ICP and systemic hemodynamic variables were noted; it was followed by recording of the same parameters every 5min till 45min (Study Period). After the completion of study period, brain relaxation score as assessed by the neurosurgeon was recorded. Arterial blood gas (ABG) was analysed every 30min starting from T₀ upto one and half hours (T₉₀), and values of various parameters were recorded. Data was analysed using appropriate statistical methods. Both mannitol and HS significantly reduced the ICP; the values were comparable in between the two groups at most of the times. The brain relaxation score was comparable in both the groups. Urine output was significantly higher with mannitol. The perioperative complications, overall hospital stay, and Glasgow outcome score at discharge were comparable in between the two groups. To conclude, both mannitol and hypertonic saline in equiosmolar concentrations produced comparable effects on ICP reduction, brain relaxation, and systemic hemodynamics.

Dexmedetomidine for Refractory Intracranial Hypertension

Dexmedetomidine (DEX) is a selective α₂ adrenergic agonist that is commonly used for sedation in the intensive care unit (ICU). The role of DEX for adjunctive treatment of refractory intracranial hypertension is poorly defined. The primary objective of this study was to determine the effect of DEX on the need for rescue therapy (ie, hyperosmolar boluses, extraventricular drain [EVD] drainages) for refractory intracranial hypertension. Secondary objectives included the number of intracranial pressure (ICP) excursions, bradycardic, hypotensive, and compromised cerebral perfusion pressure episodes. This retrospective cohort study evaluated patients admitted to the neurosurgical ICU from August 1, 2009, to July 29, 2015, and who received DEX for refractory intracranial hypertension. The objectives were compared between the 2 time periods-before (pre-DEX) and during therapy (DEX). Twenty-three patients with 26 episodes of refractory intracranial hypertension met the inclusion criteria. The number of hyperosmolar boluses was decreased after DEX therapy was initiated. Mannitol boluses required were statistically reduced (1 vs 0.5, P = .03); however, reduction in hypertonic boluses was not statistically significant (1.3 vs 0.9, P = .2). The mean number of EVD drainages per 24 hours was not significantly different between the time periods (15.7 vs 14.0, P = .35). The rate of ICP excursions did not differ between the 2 groups (24.3 vs 22.5, P = .62). When compared to pre-DEX data, there was no difference in the median number of hypotensive (0 vs 0), bradycardic (0 vs 0), or compromised cerebral perfusion pressure episodes (0.5 vs 1.0). Dexmedetomidine may avoid increases in the need for rescue therapy when used as an adjunctive treatment of refractory intracranial hypertension without compromising hemodynamics.

Considerations in Fluids and Electrolytes After Traumatic Brain Injury

Appropriate fluid management of patients with traumatic brain injury (TBI) presents a challenge for many clinicians. Many of these patients may receive osmotic diuretics for the treatment of increased intracranial pressure or develop sodium disturbances, which act to alter fluid balance. However, establishment of fluid balance is extremely important for improving patient outcomes after neurologic injury. The use of hyperosmolar fluids, such as hypertonic saline, has gained significant interest because they are devoid of dehydrating properties and may have other beneficial properties for patients with TBI. Electrolyte derangements are also common after neurologic injury, with many having neurologic manifestations. In addition, the role of electrolyte abnormalities in the secondary neurologic injury cascade is being delineated and may offer a potential future therapeutic intervention.

Evaluation of the Maintained Effect of 3% Hypertonic Saline Solution in an Animal Model of Intracranial Hypertension

Background

Current clinical treatment methods for refractory intracranial hypertension include elevation of the decubitus, ventilation adjustment, and use of hypertonic solutions such as hypertonic saline and mannitol solutions. Previous studies have shown that hypertonic solutions are particularly effective. Although several concentrations of saline solution have been proposed, a 3% solution is the most widely used. The aim of this study was to evaluate the maintained efficacy of a 3% hypertonic saline solution in an experimental model of intracranial hypertension.

Material/Methods

A porcine model of reversible intracranial hypertension was created by inserting a balloon catheter into the brain parenchyma, which was inflated and deflated to simulate intracranial hypertension and its surgical correction. The experiment included 3 groups of animals (A, B, and C) with different balloon inflation volumes. In group B, balloons were inflated 2 times to simulate reexpansion. A 20 mL/kg bolus of 3% saline solution was infused using a pump 90 minutes after the start of balloon inflation, and the effects of intracranial pressure were evaluated 60 minutes after infusion.

Results

No increases outside of the normal range were observed in mean serum sodium concentrations (p=0.09). In addition, we identified no differences within each group in serum sodium levels measured during hypertonic saline infusion (p=0.21). No significant reductions in intracranial pressure were observed in any of the 3 groups.

Conclusions

Bolus infusion of 3% hypertonic saline solution with the aid of a pump does not significantly reduce intracranial pressure in an animal model of intracranial hypertension.

Effectiveness of 7.5% hypertonic saline in children with severe traumatic brain injury

PURPOSE

Hyperosmolar therapies aim at controlling increased intracranial pressure (ICP) in patients with traumatic brain injury (TBI). The aim of this study was to evaluate the effect of 7.5% hypertonic saline (HTS) on ICP and cerebral perfusion pressure (CPP) in children with severe TBI.

MATERIALS AND METHODS

Medical records of patients 14 years or younger with severe TBI, admitted in the pediatric intensive care unit of "Aghia Sophia" Children's Hospital, Athens, Greece, during 2009 to 2015, and received HTS apart from mannitol were retrospectively reviewed. The ICP and CPP pre-HTS and 30, 60, and 120 minutes post-HTS infusion were evaluated. Furthermore, the presence of adverse effects, the long-term neurological outcome, and survival were recorded.

RESULTS

Twenty-nine patients requiring in total 136 HTS infusions were analyzed. The ICP was significantly reduced and CPP elevated at 30, 60, and 120 minutes postinfusion; and furthermore, postadministration ICP and CPP were predominantly within acceptable limits. No significant adverse effects were recorded and most of the patients survived, however, one third had severe neurological impairment at 6 months postinjury.

CONCLUSIONS

In our study, 7.5% HTS infusion as a second-tier osmotic therapy was associated with significant reduction of ICP and increase of CPP in children with severe TBI.

Hypertonic saline alleviates experimentally induced cerebral oedema through suppression of vascular endothelial growth factor and its receptor VEGFR2 expression in astrocytes

BACKGROUND

Cerebral oedema is closely related to the permeability of blood-brain barrier, vascular endothelial growth factor (VEGF) and its receptor vascular endothelial growth factor receptor 2 (VEGFR2) all of which are important blood-brain barrier (BBB) permeability regulatory factors. Zonula occludens 1 (ZO-1) and claudin-5 are also the key components of BBB. Hypertonic saline is widely used to alleviate cerebral oedema. This study aimed to explore the possible mechanisms underlying hypertonic saline that ameliorates cerebral oedema effectively.

METHODS

Middle cerebral artery occlusion (MCAO) model in Sprague-Dawley (SD) rats and of oxygen-glucose deprivation model in primary astrocytes were used in this study. The brain water content (BWC) was used to assess the effect of 10 % HS on cerebral oedema. The assessment of Evans blue (EB) extravasation was performed to evaluate the protective effect of 10 % HS on blood-brain barrier. The quantification of VEGF, VEGFR2, ZO-1 and claudin-5 was used to illustrate the mechanism of 10 % HS ameliorating cerebral oedema.

RESULTS

BWC was analysed by wet-to-dry ratios in the ischemic hemisphere of SD rats; it was significantly decreased after 10 % HS treatment (P < 0.05). We also investigated the blood-brain barrier protective effect by 10 % HS which reduced EB extravasation effectively in the peri-ischemic brain tissue. In parallel to the above notably at 24 h following MCAO, mRNA and protein expression of VEGF and VEGFR2 in the peri-ischemic brain tissue was down-regulated after 10 % HS treatment (P < 0.05). Along with this, in vitro studies showed increased VEGF and VEGFR2 mRNA and protein expression in primary astrocytes under hypoxic condition (P < 0.05), but it was suppressed after HS treatment (P < 0.05). In addition, HS inhibited the down-regulation of ZO-1, claudin-5 effectively.

CONCLUSIONS

The results suggest that 10 % HS could alleviate cerebral oedema possibly through reducing the ischemia induced BBB permeability as a consequence of inhibiting VEGF-VEGFR2-mediated down-regulation of ZO-1, claudin-5.

Extreme hypernatremia as a probable cause of fatal arrhythmia: a case report

BACKGROUND

Hypernatremia is a frequent occurrence among hospitalized patients. Severe hypernatremia is associated with mortality rates of over 60 %. Extreme hypernatremia, defined as sodium levels >190 mmol/l, is a rare occurrence. The literature on electrocardiographic changes occurring with this degree of hypernatremia is extremely scarce. We report the case of an 11-year-old Sri Lankan girl who presented with sodium levels of 226 mmol/l following infusion with 3 % hypertonic saline who developed diffuse QT prolongation leading to fatal ventricular tachycardia.

CASE PRESENTATION

An 11-year-old Sri Lankan girl presented with fever, headache, vomiting, and altered level of consciousness. Following admission she developed generalized tonic-clonic seizures and was intubated and ventilated. She had a recent history of polyuria and polydipsia. Magnetic resonance imaging of her brain revealed hydrocephalus due to possible craniopharyngioma. A ventriculoperitoneal shunt was inserted and she was infused with 3 % hypertonic saline in an attempt to reduce intracranial pressure. The following day she became polyuric and dehydrated with tachycardia and low blood pressure. Biochemistry revealed serum sodium of 226 mmol/l, measured serum osmolality of 470 mOsm/kg, urine osmolality of 280 mOsm/kg, urine spot sodium of 116 mmol/l, blood urea of 8.1 mmol/l, and blood glucose of 8.5 mmol/l. Her serum potassium, calcium, and magnesium levels were normal. Extreme hypernatremia due to infusion of 3 % hypertonic saline in the background of cranial diabetes insipidus was considered. She was managed aggressively with 5 % dextrose infusion and clear water via nasogastric feeding to correct the fluid deficit of 7 liters over 36 hours. Her sodium levels dropped to 160 mmol/l the following day. However, she developed electrocardiographic changes with widespread gross QT prolongation with ST segment deviations followed by fatal ventricular tachycardia.

CONCLUSIONS

Extreme hypernatremia is rare, and the literature on electrocardiographic changes occurring at such high levels of sodium is scarce. At present there are no established guidelines on rate and mode of correction of such high sodium levels. This case highlights the electrocardiographic changes observed during extreme hypernatremia, controversies in managing increased intracranial pressure with hypertonic saline, and dilemmas encountered in managing extreme hypernatremia.

The role of hypertonic saline dextran in trauma resuscitation

Modern trauma management has recognized the importance of using conservative fluid resuscitation regimes in order to prevent complications from fluid overload arising. Hypertonic/hyperoncotic fluids appear to provide an ideal means of facilitating this, requiring only small volumes to rapidly elevate blood pressure. Hypertonic saline dextran (HSD) was introduced in 1985 but its take up has been slow, a large part of this has been due to the lack of human trials and concerns about complications.

The current evidence has been reviewed and it is clear that HSD is an efficient means of correcting hypotension, doing so mainly by the mobilizing endogenous water. It is becoming apparent that early administration has the potential to modulate the inflammatory cascade in patients at risk of developing adult respiratory distress syndrome (ARDS) and multiorgan failure. This is reflected in the handful of human trials that show a trend towards increased survival (particularly for head injuries) and a possible reduction in ARDS. The side effect profile appears to be good, even in the presence of dehydration or penetrating trauma.

Published human trials have methodological problems and lack of power of study this has led to a reliance on animal studies. Clearly there is great potential, but before large-scale prehospital usage can be justified further well-conducted randomized human trials are needed.

Aquaporin-4 and Cerebrovascular Diseases

Cerebrovascular diseases are conditions caused by problems with brain vasculature, which have a high morbidity and mortality. Aquaporin-4 (AQP4) is the most abundant water channel in the brain and crucial for the formation and resolution of brain edema. Considering brain edema is an important pathophysiological change after stoke, AQP4 is destined to have close relation with cerebrovascular diseases. However, this relation is not limited to brain edema due to other biological effects elicited by AQP4. Till now, multiple studies have investigated roles of AQP4 in cerebrovascular diseases. This review focuses on expression of AQP4 and the effects of AQP4 on brain edema and neural cells injuries in cerebrovascular diseases including cerebral ischemia, intracerebral hemorrhage and subarachnoid hemorrhage. In the current review, we pay more attention to the studies of recent years directly from cerebrovascular diseases animal models or patients, especially those using AQP4 gene knockout mice. This review also elucidates the potential of AQP4as an excellent therapeutic target.

Critical Care Management of Increased Intracranial Pressure

Increased intracranial pressure (ICP) is a pathologic state common to a variety of serious neurologic conditions, all of which are characterized by the addition of volume to the intracranial vault. Hence all ICP therapies are directed toward reducing intracranial volume. Elevated ICP can lead to brain damage or death by two principle mechanisms: (1) global hypoxic-ischemic injury, which results from reduction of cerebral perfusion pressure (CPP) and cerebral blood flow, and (2) mechanical compression, displacement, and herniation of brain tissue, which results from mass effect associated with compartmentalized ICP gradients. In unmonitored patients with acute neurologic deterioration, head elevation (30 degrees), hyperventilation (pCO2 26-30 mmHg), and mannitol (1.0-1.5 g/kg) can lower ICP within minutes. Fluid-coupled ventricular catheters and intraparenchymal pressure transducers are the most accurate and reliable devices for measuring ICP in the intensive care unit (ICU) setting. In a monitored patient, treatment of critical ICP elevation (>20 mmHg) should proceed in the following steps: (1) consideration of repeat computed tomography (CT) scanning or consideration of definitive neurosurgical intervention, (2) intravenous sedation to attain a quiet, motionless state, (3) optimization of CPP to levels between 70 and 110 mmHg, (4) osmotherapy with mannitol or hypertonic saline, (5) hyperventilation (pCO2 26-30 mmHg), (6) high-dose pentobarbital therapy, and (7) systemic cooling to attain moderate hypothermia (32-33°C). Placement of an ICP monitor and use of a stepwise treatment algorithm are both essential for managing ICP effectively in the ICU setting.

A comparison of equivolume, equiosmolar solutions of hypertonic saline and mannitol for brain relaxation in patients undergoing elective intracranial tumor surgery: a randomized clinical trial

BACKGROUND

Hyperosmolar solutions have been used in neurosurgery to modify brain bulk and prevent neurological deterioration. The purpose of the study was to compare the effects of equivolume, equiosmolar solutions of mannitol and hypertonic saline (HTS) on brain relaxation and postoperative complications in patients undergoing elective intracranial tumor surgery.

METHODS

In this prospective, randomized study, patients with American Society of Anesthesiologists physical status I to III scheduled to undergo a craniotomy for intracranial tumors were enrolled. Patients received a 3.75 mL/kg intravenous infusion of either 3.2% HTS (group HTS, n=36) or 20% mannitol (group M, n=38). The surgeon assessed the condition of the brain using a 4-point scale after opening the dura. Recorded measures included duration of surgery, blood loss, urine output, volume and type of infused fluids, hemodynamic variables, electrolytes, glucose, creatinine, predefined postoperative complications, and length of intensive care unit and hospital stays.

RESULTS

Brain relaxation conditions in group HTS (score 1/2/3/4, n=10/17/2/7) were better than those in group M (score 1/2/3/4, n=3/18/3/14, P=0.0281). Patients in group M had higher urine output, received more crystalloids during surgery, and displayed lower central venous pressure and lower natremia at the end of surgery than did patients in group HTS. No significant differences in postoperative complications or lengths of intensive care unit and hospital stays were observed between the groups.

CONCLUSIONS

Our results suggest that HTS provides better brain relaxation than mannitol during elective intracranial tumor surgery.

A comparison of equivolume, equiosmolar solutions of hypertonic saline and mannitol for brain relaxation during elective supratentorial craniotomy

BACKGROUND

Hyperosmolar solutions have been used in neurosurgery to reduce brain volume and facilitate surgical exposure. The purpose of this study was to compare the effects of equivolume, equiosmolar solutions of mannitol and hypertonic saline (HS) on brain relaxation, intensive care unit (ICU) and hospital stay, postoperative outcomes and incidence of side-effects in patients undergoing elective supratentorial craniotomy.

METHODS

In a randomised, prospective, double-blind study, 60 patients undergoing elective supratentorial craniotomy were randomised 1:1 to receive 3 ml/kg of either 20% mannitol or 3% HS. The primary outcome was the surgical condition of the brain assessed by the neurosurgeon using a 4-point scale after opening the dura (1 = relaxed, 2 = satisfactory, 3 = firm and 4 = bulging). Secondary outcomes were electrolytes, blood gases, plasma osmolality and haemodynamic variables measured at 0 min, 30 min, 2 h and 6 h after infusion. Also, predefined postoperative complications, length of ICU and hospital stay were recorded. Appropriate statistical tests were used for comparison; p < 0.05 was considered significant.

RESULTS

There was no difference in brain relaxation [mannitol, 1(1-3) versus HS, 1(1.4) points; p = 0.55]. Patients with brain midline shift showed a worse response to hyperosmolar solutions than those without midline shift: 37% versus 8%, respectively; OR = 6.6 (95% CI, 1.54-28.83); p = 0.006. Plasma osmolality increased during the study period (6 h) in both the groups (p < 0.05 compared with baseline). No significant differences in postoperative complications or length of ICU and hospital stay were observed between the groups.

CONCLUSIONS

Single doses of 3 ml/kg of 20% mannitol and 3% HS are safe and effective for intraoperative brain debulking during elective supratentorial craniotomy, but less effective in patients with pre-existing mass effect and midline shift.

Efficacy and Safety of Continuous Micro-Pump Infusion of 3% Hypertonic Saline combined with Furosemide to Control Elevated Intracranial Pressure

Background

Elevated intracranial pressure is one of the most common problems in patients with diverse intracranial disorders, leading to increased morbidity and mortality. Effective management for increased intracranial pressure is based mainly on surgical and medical techniques with hyperosmolar therapy as one of the core medical treatments. The study aimed to explore the effects of continuous micro-pump infusions of 3% hypertonic saline combined with furosemide on intracranial pressure control.

Material/Methods

We analyzed data on 56 eligible participants with intracranial pressure >20 mmHg from March 2013 to July 2014. The target was to increase and maintain plasma sodium to a level between 145 and 155 mmol/L and osmolarity to a level of 310 to 320 mOsmol/kg.

Results

Plasma sodium levels significantly increased from 138±5 mmol/L at admission to 151±3 mmol/L at 24 h (P<0.01). Osmolarity increased from 282±11 mOsmol/kg at baseline to 311±8 mOsmol/kg at 24 h (P<0.01). Intracranial pressure significantly decreased from 32±7 mmHg to 15±6 mmHg at 24 h (P<0.01). There was a significant improvement in CPP (P<0.01). Moreover, central venous pressure, mean arterial pressure, and Glasgow Coma Scale slightly increased. However, these changes were not statistically significant.

Conclusions

Continuous infusion of 3% hypertonic saline + furosemide is effective and safe for intracranial pressure control.

Methylophiopogonanone A Protects against Cerebral Ischemia/Reperfusion Injury and Attenuates Blood-Brain Barrier Disruption In Vitro

Methylophiopogonanone A (MO-A), an active homoisoflavonoid of the Chinese herb Ophiopogon japonicus which has been shown to have protective effects on cerebral ischemia/reperfusion (I/R) injury, has been demonstrated to have anti-inflammatory and anti-oxidative properties. However, little is known about its role in cerebral I/R injury. Therefore, in this study, by using a middle cerebral artery occlusion (MCAO) and reperfusion rat model, the effect of MO-A on cerebral I/R injury was examined. The results showed that MO-A treatment reduced infarct volume and brain edema, improved neurological deficit scores, reversed animal body weight decreases, and increased animal survival time in the stroke groups. Western blotting showed that MO-A suppressed MMP-9, but restored the expression of claudin-3 and claudin-5. Furthermore, transmission electron microscopy were monitored to determine the blood-brain barrier (BBB) alterations in vitro. The results showed that MO-A markedly attenuated BBB damage in vitro. Additionally, MO-A inhibited ROS production in ECs and MMP-9 release in differentiated THP-1 cells in vitro, and suppressed ICAM-1 and VCAM-1 expression in ECs and leukocyte/EC adhesion. In conclusion, our data indicate that MO-A has therapeutic potential against cerebral I/R injury through its ability to attenuate BBB disruption by regulating the expression of MMP-9 and tight junction proteins.

Pediatric head injury: a pain for the emergency physician?

The prompt diagnosis and initial management of pediatric traumatic brain injury poses many challenges to the emergency department (ED) physician. In this review, we aim to appraise the literature on specific management issues faced in the ED, specifically: indications for neuroimaging, choice of sedatives, applicability of hyperventilation, utility of hyperosmolar agents, prophylactic anti-epileptics, and effect of hypothermia in traumatic brain injury. A comprehensive literature search of PubMed and Embase was performed in each specific area of focus corresponding to the relevant questions. The majority of the head injured patients presenting to the ED are mild and can be observed. Clinical prediction rules assist the ED physician in deciding if neuroimaging is warranted. In cases of major head injury, prompt airway control and careful use of sedation are necessary to minimize the chance of hypoxia, while avoiding hyperventilation. Hyperosmolar agents should be started in these cases and normothermia maintained. The majority of the evidence is derived from adult studies, and most treatment modalities are still controversial. Recent multicenter trials have highlighted the need to establish common platforms for further collaboration.

Refractory hypokalemia during barbiturate coma therapy used for treating refractory intracranial hypertension in traumatic brain injury

Barbiturate coma therapy (BCT) is a choice treatment for refractory intracranial hypertension after all surgical or medical managements have failed to control the intracranial pressure (ICP). It helps to reduce cerebral blood flow, cerebral metabolic rate of oxygen consumption and ICP. However, this therapy can also cause many complications. One of the underreported, but life-threatening complications is refractory hypokalemia, which can lead to subsequent rebound hyperkalemia after sudden cessation. We report our experience of managing unusual complication of refractory hypokalemia during BCT with thiopentone in postdecompressive craniectomy patient.

Management of raised intracranial pressure in children with traumatic brain injury

Increased intracranial pressure (ICP) is associated with worse outcome after traumatic brain injury (TBI). The current guidelines and management strategies are aimed at maintaining adequate cerebral perfusion pressure and treating elevated ICP. Despite controversies, ICP monitoring is important particularly after severe TBI to guide treatment and in developed countries is accepted as a standard of care. We provide a narrative review of the recent evidence for the use of ICP monitoring and management of ICP in pediatric TBI.

Brain injury from explosive blast: description and clinical management

Accumulating clinical experience is indicating that explosive blast brain injury is becoming recognized as a disease distinct from the penetrating form of blast injury as well as the classic closed head injury (CHI). In recent US conflicts in Iraq and Afghanistan, over 60% of combat casualties were from explosive blast with the hallmark explosive weapon being the improvised explosive device (IED). Explosive blast TBI is a condition afflicting many combat injured warfighters potentially constituting another category of TBI. Clinically, it shares many features with conventional TBI but possesses some unique aspects. In its mild form, it also shares many clinical features with PTSD but here again has distinct aspects. Although military medical providers depend on civilian standard of care guidelines when managing explosive blast mTBI, they are continually adapting their medical practice in order to optimize the treatment of this disease, particularly in a theater of war. It is clear that further rigorous scientific study of explosive blast mTBI at both the basic science and clinical levels is needed. This research must include improved understanding of the causes and mechanisms of explosive blast TBI as well as comprehensive epidemiologic studies to determine the prevalence of this disease and its risk factors. A widely accepted unambiguous clinical description of explosive blast mTBI with diagnostic criteria would greatly improve diagnosis. It is hoped that through appropriate research meaningful prevention, mitigation, and treatment strategies for explosive blast mTBI can be speedily realized.

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.

The function of aquaporin4 in ischemic brain edema

Cerebral ischemia injury is a primary cause of human death and long-term disability. We know that the cerebral edema induced by ischemia injury has a fatal effect on humans, which is the main cause of death for cerebral ischemia because it produces elevated intracranial pressure that leads to secondary brain damage, such as further impaired vascular perfusion and herniation of brain. Therefore, reducing the severity of brain edema has become the main therapeutic strategy for the treatment of CI. However, current treatment options for brain edema are limited and problematic. Therefore, finding novel strategies for overcoming this problem is crucial. Numerous studies demonstrated that cerebral edema may be attenuated via the regulation of AQP4 expression, thus initiating a novel therapeutic strategy against this possibly fatal condition. This review focuses on the role of AQP4 in ischemic brain edema, and its prospect as a therapeutic target.

Effect of hypertonic saline on hypotension following induction of general anesthesia: A randomized controlled trial

Background:

The aim of this study was to examine the effects of preoperatively administered i.v. hypertonic saline on hypotension following induction of general anesthesia.

Materials and Methods:

Fifty-four patients who scheduled for elective surgery were randomly allocated to two groups of 27 patients who received hypertonic saline 5% (2.3 ml/kg) or received normal saline (13 ml/kg). Infusion of hypertonic saline was done half an hour before induction of anesthesia during 30 minutes. Anesthesia was conducted in a standard protocol for all patients. Age, sex, body mass index (BMI), systolic and diastolic blood pressure (SBP, DBP), heart rate (HR) and mean arterial pressure (MAP) were assessed in all patients.

Results:

The mean age of patients was 36.68 ± 10.8 years. Forty percent of patients were male. The mean SBP at min 2 and min 5, mean of DBP at min 2, 5, and 15, mean of HR at all time points and mean of MAP at min 2 and 15 between groups were no significantly different (P > 0.05), but mean of SBP at min 10 and 15, mean of DBP at min 10, and mean of MAP at min 5 and 10 in hypertonic saline group was significantly more than the normal group (P < 0.05). Trend of SBP, DBP, HR and MAP between groups were not significantly different (P > 0.05).

Conclusions:

Infusion of hypertonic saline 5% (2.3 mg/kg) before the general anesthesia led to a useful reduction in MAP and reduced heart rate, with no episodes of severe hypotension.

The evolution of neurocritical care

Although neurocritical care as a subspecialty is a relatively young field of medicine, its origins can be traced back to ancient times. This article focuses on the progression of neurocritical care from prehistoric trepanation procedures, through the development of mechanical ventilation, management of increased intracranial pressure, and traumatic brain injury, to the establishment of the first "real" intensive care units, and finally to modern monitoring in neurocritical care, management of post-cardiac arrest patients, and the diagnosis of brain death. This article also focuses on the future direction of neurocritical care.

Update on the 2012 guidelines for the management of pediatric traumatic brain injury - information for the anesthesiologist

Traumatic brain injury (TBI) is a significant contributor to death and disability in children. Considering the prevalence of pediatric TBI, it is important for the clinician to be aware of evidence-based recommendations for the care of these patients. The first edition of the Guidelines for the Acute Medical Management of Severe Traumatic Brain Injury in Infants, Children, and Adolescents was published in 2003. The Guidelines were updated in 2012, with significant changes in the recommendations for hyperosmolar therapy, temperature control, hyperventilation, corticosteroids, glucose therapy, and seizure prophylaxis. Many of these interventions have implications in the perioperative period, and it is the responsibility of the anesthesiologist to be familiar with these guidelines.

The physiological effects of hyperosmolar resuscitation: 5% vs 3% hypertonic saline

BACKGROUND

Use of 5% normal saline (NS) is gaining renewed interest. The primary aim of our study was to compare the physiological effects after the administration of different concentrations of hypertonic saline (3% vs 5%NS) in the initial resuscitation of trauma.

METHODS

We performed a retrospective analysis of a prospectively collected database of all trauma patients who received hypertonic saline during initial resuscitation. Medical records were reviewed for serum electrolytes and serum osmolarity, coagulation parameters, complications, and mortality.

RESULTS

A total of 212 patients were included in the study, of which 170 patients received 5%NS and 42 patients received 3%NS. Both groups were similar in age (41.16 ± 19 vs 44.17 + 23.6; P = .45) and ISS score (26 [17 to 29] vs 25 [16 to 27]; P = .6). Mean serum osmolarity (316 ± 20.3 vs 294 ± 22.5; P = .02) and serum sodium levels (143 ± 8.6 vs 137 ± 10.9; P < .001) remained higher in the 5%NS group within 72 hours of admission. The pH was lower in the 5%NS group compared with the 3%NS group at 24 hours (7.29 ± .12 vs 7.33 ± .12; P = .01); however, at 48 and 72 hours (7.40 ± .07 vs 7.41 ± .07; P = .7), no difference was found. There was no difference in blood products requirement (1,734 vs 2,253 mL; P = .11) between the 2 groups.

CONCLUSIONS

The 5%NS has sustained higher serum osmolarity and serum sodium concentration within the first 72 hours without any increase in adverse effects in comparison with 3%NS.

Management of increased intracranial pressure

OPINION STATEMENT

After brain injury, neurologic intensive care focuses on the detection and treatment of secondary brain insults that may compound the initial injury. Increased intracranial pressure (ICP) contributes to secondary brain injury by causing brain ischemia, hypoxia, and metabolic dysfunction. Because ICP is easily measured at the bedside, it is the target of numerous pharmacologic and surgical interventions in efforts to improve brain physiology and limit secondary injury. However, ICP may not adequately reflect the metabolic health of the underlying brain tissue, particularly in cases of focal brain injury. As a result, ICP control alone may be insufficient to impact patients' long-term recovery. Further studies are needed to better understand the combination of cerebral, hemodynamic, and metabolic markers that are best utilized to ensure optimal brain and systemic recovery and overall patient outcome after brain injury.

Hypernatremia in patients with severe traumatic brain injury: a systematic review

BACKGROUND

Hypernatremia is common following traumatic brain injury (TBI) and occurs from a variety of mechanisms, including hyperosmotic fluids, limitation of free water, or diabetes insipidus. The purpose of this systematic review was to assess the relationship between hypernatremia and mortality in patients with TBI.

METHODS

We searched the following databases up to November 2012: MEDLINE, EMBASE, and CENTRAL. Using a combination of MeSH and text terms, we developed search filters for the concepts of hypernatremia and TBI and included studies that met the following criteria: (1) compared hypernatremia to normonatremia, (2) adult patients with TBI, (3) presented adjusted outcomes for mortality or complications.

RESULTS

Bibliographic and conference search yielded 1,152 citations and 11 abstracts, respectively. Sixty-five articles were selected for full-text review with 5 being included in our study. All were retrospective cohort studies totaling 5,594 (range 100-4,296) patients. There was marked between-study heterogeneity. The incidence of hypernatremia ranged between 16% and 40%. Use of hyperosmolar therapy was presented in three studies (range 14-85% of patients). Hypernatremia was associated with increased mortality across all four studies that presented this outcome. Only one study considered diabetes insipidus (DI) in their analysis where hypernatremia was associated with increased mortality in patients who did not receive DDAVP.

CONCLUSIONS

Although hypernatremia was associated with increased mortality in the included studies, there was marked between-study heterogeneity. DI was a potential confounder in several studies. Considering these limitations, the clinical significance of hypernatremia in TBI is difficult to establish at this stage.

Complications associated with prolonged hypertonic saline therapy in children with elevated intracranial pressure

OBJECTIVES

Safe upper limits for therapeutic hypernatremia in the treatment of intracranial hypertension have not been well established. We investigated complications associated with hypernatremia in children who were treated with prolonged infusions of hypertonic saline.

DESIGN

Retrospective chart analysis.

SETTING

PICU in university-affiliated children's hospital.

PATIENTS

All children from 2004 to 2009 requiring intracranial pressure monitoring (external ventricular drain or fiberoptic intraparenchymal monitor) for at least 4 days who were treated with hypertonic saline infusion for elevated intracranial pressure and did not meet exclusion criteria.

INTERVENTION

Continuous hypertonic saline infusion on a sliding scale was used to achieve target sodium levels that would keep intracranial pressure less than 20 mm Hg once the conventional therapies failed.

MEASUREMENTS AND MAIN RESULTS

Eighty-eight children met inclusion criteria. Etiologies of elevated intracranial pressure included trauma (n = 48), ischemic or hemorrhagic stroke (n = 20), infection (n = 8), acute disseminated encephalomyelitis (n = 5), neoplasm (n = 2), and others (n = 5). The mean peak serum sodium was 171.3 mEq/L (range, 150-202). The mean Glasgow Outcome Score was 2.8 (± 1.1) at time of discharge from the hospital. Overall mortality was 15.9%. Children with sustained (> 72 hr) serum sodium levels above 170 mEq/L had a significantly higher occurrence of thrombocytopenia (p < 0.001), renal failure (p < 0.001), neutropenia (p = 0.006), and acute respiratory distress syndrome (p = 0.029) after controlling for variables of age, gender, Pediatric Risk of Mortality score, duration of barbiturate-induced coma, duration of intracranial pressure monitoring, vasopressor requirements, and underlying pathology. Children with sustained serum sodium levels greater than 165 mEq/L had a significantly higher prevalence of anemia (p < 0.001).

CONCLUSIONS

Children treated by continuous hypertonic saline infusion for intracranial hypertension whose serum sodium levels exceeded certain thresholds experienced significantly more events of acute renal failure, thrombocytopenia, neutropenia, anemia, and acute respiratory distress syndrome than those whose sodium level was maintained below these thresholds.

Central Nervous System Infections

Central nervous system (CNS) infections—i.e., infections involving the brain (cerebrum and cerebellum), spinal cord, optic nerves, and their covering membranes—are medical emergencies that are associated with substantial morbidity, mortality, or long-term sequelae that may have catastrophic implications for the quality of life of affected individuals. Acute CNS infections that warrant neurointensive care (ICU) admission fall broadly into three categories—meningitis, encephalitis, and abscesses—and generally result from blood-borne spread of the respective microorganisms. Other causes of CNS infections include head trauma resulting in fractures at the base of the skull or the cribriform plate that can lead to an opening between the CNS and the sinuses, mastoid, the middle ear, or the nasopharynx. Extrinsic contamination of the CNS can occur intraoperatively during neurosurgical procedures. Also, implanted medical devices or adjunct hardware (e.g., shunts, ventriculostomies, or external drainage tubes) and congenital malformations (e.g., spina bifida or sinus tracts) can become colonized and serve as sources or foci of infection. Viruses, such as rabies, herpes simplex virus, or polioviruses, can spread to the CNS via intraneural pathways resulting in encephalitis. If infection occurs at sites (e.g., middle ear or mastoid) contiguous with the CNS, infection may spread directly into the CNS causing brain abscesses; alternatively, the organism may reach the CNS indirectly via venous drainage or the sheaths of cranial and spinal nerves. Abscesses also may become localized in the subdural or epidural spaces. Meningitis results if bacteria spread directly from an abscess to the subarachnoid space. CNS abscesses may be a result of pyogenic meningitis or from septic emboli associated with endocarditis, lung abscess, or other serious purulent infections. Breaches of the blood–brain barrier (BBB) can result in CNS infections. Causes of such breaches include damage (e.g., microhemorrhage or necrosis of surrounding tissue) to the BBB; mechanical obstruction of microvessels by parasitized red blood cells, leukocytes, or platelets; overproduction of cytokines that degrade tight junction proteins; or microbe-specific interactions with the BBB that facilitate transcellular passage of the microorganism. The microorganisms that cause CNS infections include a wide range of bacteria, mycobacteria, yeasts, fungi, viruses, spirochaetes (e.g., neurosyphilis), and parasites (e.g., cerebral malaria and strongyloidiasis). The clinical picture of the various infections can be nonspecific or characterized by distinct, recognizable clinical syndromes. At some juncture, individuals with severe acute CNS infections require critical care management that warrants neuro-ICU admission. The implications for CNS infections are serious and complex and include the increased human and material resources necessary to manage very sick patients, the difficulties in triaging patients with vague or mild symptoms, and ascertaining the precise cause and degree of CNS involvement at the time of admission to the neuro-ICU. This chapter addresses a wide range of severe CNS infections that are better managed in the neuro-ICU. Topics covered include the medical epidemiology of the respective CNS infection; discussions of the relevant neuroanatomy and blood supply (essential for understanding the pathogenesis of CNS infections) and pathophysiology; symptoms and signs; diagnostic procedures, including essential neuroimaging studies; therapeutic options, including empirical therapy where indicated; and the perennial issue of the utility and effectiveness of steroid therapy for certain CNS infections. Finally, therapeutic options and alternatives are discussed, including the choices of antimicrobial agents best able to cross the BBB, supportive therapy, and prognosis.

PRO: osmotherapy for the treatment of acute intracranial hypertension

Persisting severe brain edema causes intracranial hypertension and is associated with poor patient outcome. The treatment of acute intracranial hypertension is complex and multimodal. The most important options for medical treatment include controlled ventilation and osmotherapy, maintenance of brain and body homeostasis, and sedation. Osmotherapy is recommended in all relevant guidelines. The 2 osmotic agents most frequently used are mannitol and hypertonic saline. Both reduce intracranial pressure and improve cerebral perfusion and cerebral oxygen delivery. However, hypertonic saline seems advantageous over mannitol in many situations. In multitrauma patients, hypertonic saline contributes to hemodynamic stabilization and to the prevention of secondary insults. In addition, hypertonic saline has neurohumoral and immunologic effects, which may be beneficial in cerebral resuscitation.

Osmotherapy in brain edema: a questionable therapy

Despite the fact that it has been used since the 1960s in diseases associated with brain edema and has been investigated in >150 publications on head injury, very little has been published on the outcome of osmotherapy. We can only speculate whether osmotherapy improves outcome, has no effect on outcome, or leads to worse outcome. Here we describe the action and potentially beneficial and adverse effects of the 2 most commonly used osmotic solutions, mannitol and hypertonic saline, and present some critical aspects of their use. There is a well-documented transient intracranial pressure (ICP)-reducing effect of osmotherapy, but an adverse rebound increase in ICP after its withdrawal has been discussed extensively in the literature and is an expected pathophysiological phenomenon. From side effects related to renal and pulmonary failure, electrolyte disturbances, and a rebound increase in ICP, osmotherapy can be negative for outcome, which may explain why we lack scientific support for its use. These drawbacks, and the fact that the most recent Cochrane meta-analyses of osmotherapy in brain edema and stroke could not find any beneficial effects on outcome, make routine use of osmotherapy in brain edema doubtful. Nevertheless, the use of osmotherapy as a temporary measure may be justified to acutely prevent brain stem compression until other measures, such as evacuation of space-occupying lesions or decompressive craniotomy, can be performed. This article is the Con part in a Pro-Con debate in the present journal on the general routine use of osmotherapy in brain edema.

Monitoring and intraoperative management of elevated intracranial pressure and decompressive craniectomy

Elevated intracranial pressure can be caused by a variety of underlying conditions. Several physiologic and pharmacologic factors have a significant impact on intracranial hypertension, mostly caused by changes on cerebral blood volume, flow, and oxygenation. There are many therapies that can be used to decrease intracranial pressure ranging from pharmacologic to the surgical decompressive removal of the calvarium. Special consideration is made for the anesthetic management of these patients perioperatively.

Hypertonic resuscitation after severe injury: is it of benefit?

There is a wealth of preclinical data suggesting potential benefit from the administration of hypertonic solutions after severe injury with hypovolemic shock, including improved tissue perfusion, improved flow through the microcirculation, and modulation of the inflammatory response, which may mitigate subsequent organ failure. However, despite these potential advantages, clinical trials of hypertonic resuscitation early after injury have failed to demonstrate significant benefit for resuscitation of hemorrhagic shock, and although there is no difference in overall mortality, there appears to be a trend toward earlier mortality among those receiving hypertonic fluids. Likewise, for TBI there are data suggesting that hypertonic fluids should support cerebral perfusion and mitigate intracranial hypertension, yet the clinical trials of early administration to these patients have also failed to show benefit. Further study is warranted in this patient population, as a longer period of hypertonicity may be required to show a clinical effect. Assessment of long-term neurologic outcome in this patient population remains the gold standard in determining benefit.

Advances in spontaneous intracerebral haemorrhage

OBJECTIVES

  To assess the evidence and available literature on the clinical, pathogenetic, prognostic and therapeutic aspects of intracerebral haemorrhage.

METHODS

  The most important manuscripts and reviews on the subject were considered. Information was collected from Medline, Embase & National Library of Medicine over the last 40 years up to Oct 2011. The bibliographies of relevant articles were searched for additional references. The most up to date and randomised trials were given preference. Clinical guidelines including AHA/ASA, Royal college of Physicians, NICE, Scottish Intercollegiate guidelines and several others were taken into consideration.

FINDINGS

  There are numerous advances in the understanding of the pathogenesis and management, but hardly any change in the overall mortality in the last few decades. There is a poor understanding of the results of surgical trials that has resulted in a large drop in surgical intervention since 2007. INTERPRETATIONS AND IMPLICATIONS:  Advances in neuroimaging and neurophysiology have improved our understanding of the mechanisms of neuronal injury and existence of perihaematomal 'tissue at risk'. Numerous new therapeutic targets have been identified. There is a lot of misunderstanding of the results of the newer surgical trials which need to be clarified. The importance of cerebral amyloid angiopathy and microbleeds in older patients is increasingly recognised. Control of hypertension is the most important public health measure. Stroke units provide the best outcomes for the patients.

Intracerebral hemorrhage: clinical overview and pathophysiologic concepts

Intracerebral hemorrhage is by far the most destructive form of stroke. Apart from the management in a specialized stroke or neurological intensive care unit (NICU), no specific therapies have been shown to consistently improve outcomes after ICH. Current guidelines endorse early aggressive optimization of physiologic derangements with ventilatory support when indicated, blood pressure control, reversal of any preexisting coagulopathy, intracranial pressure monitoring for certain cases, osmotherapy, temperature modulation, seizure prophylaxis, treatment of hyerglycemia, and nutritional support in the stroke unit or NICU. Ventriculostomy is the cornerstone of therapy for control of intracranial pressure patients with intraventricular hemorrhage. Surgical hematoma evacuation does not improve outcome for more patients, but is a reasonable option for patients with early worsening due to mass effect due to large cerebellar or lobar hemorrhages. Promising experimental treatments currently include ultra-early hemostatic therapy, intraventricular clot lysis with thrombolytics, pioglitazone, temperature modulation, and deferoxamine to reduce iron-mediated perihematomal inflammation and tissue injury.

Novel treatment targets for cerebral edema

Cerebral edema is a common finding in a variety of neurological conditions, including ischemic stroke, traumatic brain injury, ruptured cerebral aneurysm, and neoplasia. With the possible exception of neoplasia, most pathological processes leading to edema seem to share similar molecular mechanisms of edema formation. Challenges to brain-cell volume homeostasis can have dramatic consequences, given the fixed volume of the rigid skull and the effect of swelling on secondary neuronal injury. With even small changes in cellular and extracellular volume, cerebral edema can compromise regional or global cerebral blood flow and metabolism or result in compression of vital brain structures. Osmotherapy has been the mainstay of pharmacologic therapy and is typically administered as part of an escalating medical treatment algorithm that can include corticosteroids, diuretics, and pharmacological cerebral metabolic suppression. Novel treatment targets for cerebral edema include the Na(+)-K(+)-2Cl(-) co-transporter (NKCC1) and the SUR1-regulated NC(Ca-ATP) (SUR1/TRPM4) channel. These two ion channels have been demonstrated to be critical mediators of edema formation in brain-injured states. Their specific inhibitors, bumetanide and glibenclamide, respectively, are well-characterized Food and Drug Administration-approved drugs with excellent safety profiles. Directed inhibition of these ion transporters has the potential to reduce the development of cerebral edema and is currently being investigated in human clinical trials. Another class of treatment agents for cerebral edema is vasopressin receptor antagonists. Euvolemic hyponatremia is present in a myriad of neurological conditions resulting in cerebral edema. A specific antagonist of the vasopressin V1A- and V2-receptor, conivaptan, promotes water excretion while sparing electrolytes through a process known as aquaresis.

Hydroelectrolytic balance and cerebral relaxation with hypertonic isoncotic saline versus mannitol (20%) during elective neuroanesthesia

BACKGROUND AND OBJECTIVES

Cerebral relaxation during intracranial surgery is necessary, and hiperosmolar therapy is one of the measures used to this end. Frequently, neurosurgical patients have sodium imbalances. The objective of the present study was to quantify and determine cerebral relaxation and duration of hydroelectrolytic changes secondary to the use of mannitol versus hypertonic isoncotic solution (HIS) during neurosurgery.

METHODS

Cerebral relaxation and hydroelectrolytic changes were evaluated in 29 adult patients before de beginning of infusion, and 30 and 120 minutes after the infusion of equiosmolar loads of approximately 20% mannitol (250 mL) or HIS (120 mL). The volume of intravenous fluids infused and diuresis were recorded. A p < 0.05 was considered significant.

RESULTS

A statistically significant difference in cerebral relaxation between both groups was not observed. Although several changes in electrolyte levels and acid-base balance with mannitol or HIS reached statistical significance only the reduction in plasma sodium 30 minutes after infusion of mannitol, mean of 6.42 ± 0.40 mEq.L(-1), and the increase in chloride, mean of 5.41 ± 0.96 mEq.L(-1) and 5.45 ± 1.45 mEq.L(-1) 30 and 120 minutes after infusion of HIS, caused a transitory dislocation of serum ion levels from normal range. The mannitol (20%) group had a significantly greater diuresis at both times studied compared with HIS group.

CONCLUSIONS

A single dose of hypertonic isoncotic saline solution [7.2% NaCl/6% HES (200/0.5)] and mannitol (20%) with equivalent osmolar loads were effective and safe in producing cerebral relaxation during elective neurosurgical procedures under general anesthesia.

Acute liver failure: current practice and recent advances

ALF is an important cause of liver-related morbidity and mortality. Advances in the management of ICH and SIRS, and cardiorespiratory, metabolic, and renal support have improved the outlook of such patients. Early transfer to a liver transplant center is essential. Routine use of NAC is recommended for patients with early hepatic encephalopathy, irrespective of the etiology. The role of hypothermia remains to be determined. Liver transplantation plays a critical role, particularly for those with advanced encephalopathy. Several detoxification and BAL support systems have been developed to serve as a bridge to transplantation or to spontaneous recovery. However, such systems lack sufficient reliability and efficacy to be applied routinely in clinical practice. Hepatocyte and stem cell transplantation may provide valuable adjunctive therapy in the future.