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

Brain computed tomography after resuscitation from in-hospital cardiac arrest

BACKGROUND

Few data characterize the role of brain computed tomography (CT) after resuscitation from in-hospital cardiac arrest (IHCA). We hypothesized that identifying a neurological etiology of arrest or cerebral edema on brain CT are less common after IHCA than after resuscitation from out-of-hospital cardiac arrest (OHCA).

METHODS

We included all patients comatose after resuscitation from IHCA or OHCA in this retrospective cohort analysis. We abstracted patient and arrest clinical characteristics, as well as pH and lactate, to estimate systemic illness severity. Brain CT characteristics included quantitative measurement of the grey-to-white ratio (GWR) at the level of the basal ganglia and qualitative assessment of sulcal and cisternal effacement. We compared GWR distribution by stratum (no edema ≥1.30, mild-to-moderate <1.30 and >1.20, severe ≤1.20) and newly identified neurological arrest etiology between IHCA and OHCA groups.

RESULTS

We included 2,306 subjects, of whom 420 (18.2%) suffered IHCA. Fewer IHCA subjects underwent post-arrest brain CT versus OHCA subjects (149 (35.5%) vs 1,555 (82.4%), p < 0.001). Cerebral edema for IHCA versus OHCA was more often absent (60.1% vs. 47.5%) or mild-to-moderate (34.3% vs. 27.9%) and less often severe (5.6% vs. 24.6%). A neurological etiology of arrest was identified on brain CT in 0.5% of IHCA versus 3.2% of OHCA.

CONCLUSIONS

Although severe edema was less frequent in IHCA relative to OHCA, mild-to-moderate or severe edema occurred in one in three patients after IHCA. Unsuspected neurological etiologies of arrest were rarely discovered by CT scan in IHCA patients.

Clinical Management in Traumatic Brain Injury

Traumatic brain injury is one of the leading causes of morbidity and mortality worldwide and is one of the major public healthcare burdens in the US, with millions of patients suffering from the traumatic brain injury itself (approximately 1.6 million/year) or its repercussions (2-6 million patients with disabilities). The severity of traumatic brain injury can range from mild transient neurological dysfunction or impairment to severe profound disability that leaves patients completely non-functional. Indications for treatment differ based on the injury's severity, but one of the goals of early treatment is to prevent secondary brain injury. Hemodynamic stability, monitoring and treatment of intracranial pressure, maintenance of cerebral perfusion pressure, support of adequate oxygenation and ventilation, administration of hyperosmolar agents and/or sedatives, nutritional support, and seizure prophylaxis are the mainstays of medical treatment for severe traumatic brain injury. Surgical management options include decompressive craniectomy or cerebrospinal fluid drainage via the insertion of an external ventricular drain. Several emerging treatment modalities are being investigated, such as anti-excitotoxic agents, anti-ischemic and cerebral dysregulation agents, S100B protein, erythropoietin, endogenous neuroprotectors, anti-inflammatory agents, and stem cell and neuronal restoration agents, among others.

Asian Pacific Association for the Study of the Liver clinical practice guidelines on liver transplantation

Liver transplantation is a highly complex and challenging field of clinical practice. Although it was originally developed in western countries, it has been further advanced in Asian countries through the use of living donor liver transplantation. This method of transplantation is the only available option in many countries in the Asia-Pacific region due to the lack of deceased organ donation. As a result of this clinical situation, there is a growing need for guidelines that are specific to the Asia-Pacific region. These guidelines provide comprehensive recommendations for evidence-based management throughout the entire process of liver transplantation, covering both deceased and living donor liver transplantation. In addition, the development of these guidelines has been a collaborative effort between medical professionals from various countries in the region. This has allowed for the inclusion of diverse perspectives and experiences, leading to a more comprehensive and effective set of guidelines.

Effect of hyperchloremia on mortality of pediatric trauma patients: a retrospective cohort study

BACKGROUND

Hyperchloremia is often encountered due to the frequent administration of intravenous fluids in critically ill patients with conditions such as shock or hypotension in the pediatric intensive care unit, and high serum levels of chloride are associated with poor clinical outcomes.

OBJECTIVES

This study aimed to determine the association between hyperchloremia and in-hospital mortality in pediatric patients with major trauma.

DESIGN AND SETTING

This retrospective cohort study was conducted at a tertiary university hospital in Turkey.

METHODS

Data were collected between March 2020 and April 2022. Patients aged 1 month to 18 years with major trauma who received intravenous fluids with a concentration > 0.9% sodium chloride were enrolled. Hyperchloremia was defined as a serum chloride level > 110 mmol/L. Clinical and laboratory data were compared between the survivors and nonsurvivors.

RESULTS

The mortality rate was 23% (n = 20). The incidence of hyperchloremia was significantly higher in nonsurvivors than in survivors (P = 0.05). In multivariate logistic analysis, hyperchloremia at 48 h was found to be an independent risk factor for mortality in pediatric patients with major trauma.

CONCLUSIONS

In pediatric patients with major trauma, hyperchloremia at 48-h postadmission was associated with 28-day mortality. This parameter might be a beneficial prognostic indicator.

Comparison of 20% mannitol and 3% hypertonic saline for intraoperative brain relaxation during supratentorial brain tumour craniotomy in patients with a midline shift

PURPOSE OF THE STUDY

A prospective, randomized, double-blind study was designed to assess differences in brain relaxation between 20% mannitol and 3% hypertonic saline (HS) during elective supratentorial brain tumour surgery in patients with midline shift.

MATERIAL AND METHODS

Sixty patients undergoing supratentorial craniotomy for tumour resection were enrolled to receive either 5mL/kg of 20% mannitol (n=30) or 3% HS (n=30) administered at skin incision. PCO2 in arterial blood was maintained within 35-40mmHg and arterial blood pressure was controlled within baseline values ±20%. The primary outcome was the proportion of satisfactory brain relaxation. The surgeon assessed brain relaxation on a four-point scale (1=excellent with no swelling, 2=minimal swelling, 3=serious swelling not requiring treatment, 4=severe swelling requiring treatment). Postsurgical intracranial changes determined by imaging techniques, postoperative complications, PACU and hospital stay, and mortality at 30 days were also recorded. Appropriate statistical tests were used for comparison; P<0.05 was considered as significant. This trial was registered in Eudract.ema.europa.eu (#2021-006290-40).

RESULTS

There was no difference in brain relaxation: 2.00 [1.00-2.00] and 2.00 [1.75-3.00] for patients in mannitol and HS groups, respectively (P=0.804). Tumour size (OR: 0.99, 95% CI: 0.99-1.01; P=0.371), peritumoral oedema classification (OR: 0.57, 95% CI: 0.11-2.84; P=0.493), mass effect (OR: 0.86, 95% CI: 0.16-4.87; P=0.864), anaesthesia (OR: 4.88, 95% CI: 0.82-28.96; P=0.081) and midline shift (OR: 5.00, 95% CI: 0.84-29.70; P=0.077) did not have a significant influence on brain swelling in patients treated with either mannitol or HS. No significant differences in perioperative outcomes, mortality and length of PACU and hospital stay were observed.

CONCLUSIONS

5mL/kg of 20% mannitol or 3% HS result in similar brain relaxation scores in patients undergoing craniotomy for supratentorial brain tumour with midline shift.

External Ventricular Drains versus Intraparenchymal Pressure Monitors in the Management of Moderate to Severe Traumatic Brain Injury: Experience at Two Academic Centers over a Decade

OBJECTIVE

The choice between external ventricular drain (EVD) and intraparenchymal monitor (IPM) for managing intracranial pressure in moderate-to-severe traumatic brain injury (msTBI) patients remains controversial. This study aimed to investigate factors associated with receiving EVD versus IPM and to compare outcomes and clinical management between EVD and IPM patients.

METHODS

Adult msTBI patients at 2 similar academic institutions were identified. Logistic regression was performed to identify factors associated with receiving EVD versus IPM (model 1) and to compare EVD versus IPM in relation to patient outcomes after controlling for potential confounders (model 2), through odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Of 521 patients, 167 (32.1%) had EVD and 354 (67.9%) had IPM. Mean age, sex, and Injury Severity Score were comparable between groups. Epidural hemorrhage (EDH) (OR 0.43, 95% CI 0.21-0.85), greater midline shift (OR 0.90, 95% CI 0.82-0.98), and the hospital with higher volume (OR 0.14, 95% CI 0.09-0.22) were independently associated with lower odds of receiving an EVD whereas patients needing a craniectomy were more likely to receive an EVD (OR 2.04, 95% CI 1.12-3.73). EVD patients received more intense medical treatment requiring hyperosmolar therapy compared to IPM patients (64.1% vs. 40.1%). No statistically significant differences were found in patient outcomes.

CONCLUSIONS

While EDH, greater midline shift, and hospital with larger patient volume were associated with receiving an IPM, the need for a craniectomy was associated with receiving an EVD. EVD patients received different clinical management than IPM patients with no significant differences in patient outcomes.

Acute Liver Failure Guidelines

Acute liver failure (ALF) is a rare, acute, potentially reversible condition resulting in severe liver impairment and rapid clinical deterioration in patients without preexisting liver disease. Due to the rarity of this condition, published studies are limited by the use of retrospective or prospective cohorts and lack of randomized controlled trials. Current guidelines represent the suggested approach to the identification, treatment, and management of ALF and represent the official practice recommendations of the American College of Gastroenterology. The scientific evidence was reviewed using the Grading of Recommendations, Assessment, Development and Evaluation process to develop recommendations. When no robust evidence was available, expert opinions were summarized using Key Concepts. Considering the variety of clinical presentations of ALF, individualization of care should be applied in specific clinical scenarios.

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.

Association of hyperchloremia and acute kidney injury in pediatric patients with moderate and severe traumatic brain injury

PURPOSE

Acute kidney injury (AKI) is an established complication of adult traumatic brain injury (TBI) and known risk factor for mortality. Evidence demonstrates an association between hyperchloremia and AKI in critically ill adults but studies in children are scarce. Given frequent use of hypertonic saline in the management of pediatric TBI, we believe the incidence of hyperchloremia will be high and hypothesize that it will be associated with development of AKI.

METHODS

Single-center retrospective cohort study was completed at an urban, level 1 pediatric trauma center. Children > 40 weeks corrected gestational age and < 21 years of age with moderate or severe TBI (presenting GCS < 13) admitted between January 2016 and December 2021 were included. Primary study outcome was presence of AKI (defined by pediatric Kidney Disease: Improving Global Outcomes criteria) within 7 days of hospitalization and compared between patients with and without hyperchloremia (serum chloride ≥ 110 mEq/L).

RESULTS

Fifty-two children were included. Mean age was 5.75 (S.D. 5.4) years; 60% were male (31/52); and mean presenting GCS was 6 (S.D. 2.9). Thirty-seven patients (71%) developed hyperchloremia with a mean peak chloride of 125 (S.D. 12.0) mEq/L and mean difference between peak and presenting chloride of 16 (S.D. 12.7) mEq/L. Twenty-three patients (44%) developed AKI; of those with hyperchloremia, 62% (23/37) developed AKI, while among those without hyperchloremia, 0% (0/15) developed AKI (difference 62%, 95% CI 42-82%, p < 0.001). Attributable risk of hyperchloremia leading to AKI was 62.2 (95% CI 46.5-77.8, p = 0.0015).

CONCLUSION

Hyperchloremia is common in the management of pediatric TBI and is associated with development of AKI. Risk appears to be associated with both the height of serum chloride and duration of hyperchloremia.

Ultrasonic optic nerve sheath diameter could improve the prognosis of acute ischemic stroke in the intensive care unit

Objectives: Stroke patients with high intracranial pressure (ICP) may have poor prognosis. Non-invasive ultrasonic optic nerve sheath diameter (ONSD) could evaluate increased ICP. To investigate whether ONSD is valuable for prognosis of patients with acute ischemic stroke (AIS). Methods: AIS receiving intensive care were recruited with the Glasgow Coma Scale (GCS) score. Patients in group A underwent ultrasonic ONSD to assess ICP voluntarily, whereas group B without ONSD. Patients were followed up at discharge and once a week for 3 months with Glasgow Outcome Scale (GOS) score (four to five scores indicated good prognosis and one to three scores indicated poor prognosis). Results: Forty-nine patients were included. GCS scores did not differ significantly between groups A (26 patients) and B (8 ± 3 vs. 7 ± 3, p < 0.05). In group A, ONSD was 5.01 ± 0.48 mm, which correlated with GCS score (p < 0.05). At discharge, the GOS score was higher in group A than in group B (3.35 ± 1.35 vs. 2.57 ± 1.121, p = 0.034). The proportion of patients with a good prognosis was higher in group A than in group B (46.2% vs. 13.0%, p = 0.006). At discharge and after 3 months of follow-up, ONSD at admission was correlated with the GOS score in group A (r = -0.648 [p < 0.05] and -0.731 [p < 0.05], respectively). After 3 months of follow-up, the GOS score was higher in group A than group B (3.00 ± 1.673 vs. 2.04 ± 1.430, p < 0.05). The proportion of patients with a good prognosis was higher in group A than in group B (46.2% vs. 21.2%, p = 0.039). The Kaplan-Meier curve showed a higher rate of good prognosis in group A than in group B. ONSD (p < 0.05) was an independent predictor of poor prognosis. Conclusion: Non-invasive ultrasonic ONSD could be useful in improving the prognosis of patients with AIS receiving intensive care.

Computational modelling of cerebral oedema and osmotherapy following ischaemic stroke

In ischaemic stroke, a large reduction in blood supply can lead to the breakdown of the blood brain barrier and to cerebral oedema after reperfusion therapy. Cerebral oedema is marked by elevated intracranial pressure (ICP), tissue herniation and reduced cerebral perfusion pressure. In clinical settings, osmotherapy has been a common practice to decrease ICP. However, there are no guidelines on the choice of administration protocol parameters such as injection doses, infusion time and retention time. Most importantly, the effects of osmotherapy have been proven controversial since the infusion of osmotic agents can lead to a range of side effects. Here, a new Finite Element model of brain oedema and osmotherapy is thus proposed to predict treatment outcome. The model consists of three components that simulate blood perfusion, oedema, and osmotherapy, respectively. In the perfusion model (comprising arteriolar, venous, and capillary blood compartments), an anatomically accurate brain geometry is used to identify regions with a perfusion reduction and potential oedema occurrence in stroke. The oedema model is then used to predict ICP using a porous circulation model with four fluid compartments (arteriolar blood, venular blood, capillary blood, and interstitial fluid). In the osmotherapy model, the osmotic pressure is varied and the changes in ICP during different osmotherapy episodes are quantified. The simulation results of the model show excellent agreement with available clinical data and the model is employed to study osmotherapy under various parameters. Consequently, it is demonstrated how therapeutic strategies can be proposed for patients with different pathological parameters based on simulations.

Administration of 3% Sodium Chloride and Local Infusion Reactions

Three-percent sodium chloride (3% NaCl) is a hyperosmolar agent used to treat hyponatremic encephalopathy or other cases of increased intracranial pressure. A barrier to the use of 3% NaCl is the perceived risk of local infusion reactions when administered through a peripheral vein. We sought to evaluate reports of local infusion reactions associated with 3% NaCl over a 10-year period throughout a large healthcare system. A query was conducted through the Risk Master database to determine if there were any local infusion reactions associated with peripheral 3% NaCl administration throughout the entire UPMC health system, which consists of 40 hospitals with 8400 licensed beds, over a 10-year time period from 14 May 2010 to 14 May 2020. Search terms included infiltrations, extravasations, phlebitis, IV site issues, and IV solutions. There were 23,714 non-chemotherapeutic and non-contrast-associated intravenous events, of which 4678 (19.7%) were at UPMC Children’s Hospital. A total of 2306 patients received 3% NaCl, of whom 836 (35.8%) were at UPMC Children’s Hospital. There were no reported local infusion reactions with 3% NaCl. There were no reported local infusion reaction events associated with 3% NaCl in a large healthcare system over a 10-year period. This suggests that 3% NaCl can be safely administered through a peripheral IV or central venous catheter.

Early hyperchloremia and outcomes after acute ischemic stroke

OBJECTIVE

Based on the relationship between hyperchloremia and mortality in critically ill patients, we investigated the effect of early hyperchloremia on 90-day outcomes in acute ischemic stroke patients.

MATERIALS AND METHODS

Acute ischemic stroke patients recruited within 5 h of symptom onset were analyzed. Hyperchloremia (defined as 110 mmol/L or greater) at either baseline, or 24, or 48 h after randomization was identified and classified as one occurrence or two or more occurrences. Logistic regression analyses were performed to determine the effects of hyperchloremia on: favorable outcomes (defined by a National Institutes of Health Stroke Scale and/or modified Rankin scale scores of 0-1) at 90-day, death or disability at 90-day, and death within 90-day after accounting for potential confounders.

RESULTS

Among the total of 1275 patients, one and two or more occurrence of hyperchloremia within 48 h were seen in 191 patients and 108 patients, respectively. Compared with patients without hyperchloremia, patients with two or more occurrences of hyperchloremia at significantly higher odds of lack of favorable outcomes (odds ratio 3.0, 95% confidence interval 1.8-5.1) and death or disability (odds ratio 2.6, 95% confidence interval 1.6-4.1) at 90-day after adjustment for age, National Institutes of Health Stroke Scale score strata (6-9, 10-19, ≥ 20), study intervention, initial SBP, and intra-arterial treatment.

CONCLUSIONS

The independent association between sustained hyperchloremia and lack of favorable outcomes at 90-day suggest that avoidance of hyperchloremia may reduce the rate of lack of favorable outcomes and death or disability in patients with acute ischemic stroke.

A teaspoon of sugar and a pinch of salt: Reviewing hyperosmolar therapy

ABSTRACT

The traditional hyperosmolar agents used to treat patients with elevated intracranial pressure are mannitol and hypertonic sodium chloride solution. This article focuses on some of the pros and cons of these treatments for managing cerebral edema.

Aquaporin 4 in Traumatic Brain Injury: From Molecular Pathways to Therapeutic Target

Traumatic brain injury (TBI) is known as an acute degenerative pathology of the central nervous system, and has been shown to increase brain aquaporin 4 (AQP4) expression. Various molecular mechanisms affect AQP4 expression, including neuronal high mobility group box 1, forkhead box O3a, vascular endothelial growth factor, hypoxia-inducible factor-1 α (HIF-1 α) sirtuin 2, NF-κB, Malat1, nerve growth factor and Angiotensin II receptor type 1. In addition, inhibition of AQP4 with FK-506, MK-801 (indirectly by targeting N-methyl-D-aspartate receptor), inactivation of adenosine A2A receptor, levetiracetam, adjudin, progesterone, estrogen, V1aR inhibitor, hypertonic saline, erythropoietin, poloxamer 188, brilliant blue G, HIF-1alpha inhibitor, normobaric oxygen therapy, astaxanthin, epigallocatechin-3-gallate, sesamin, thaliporphine, magnesium, prebiotic fiber, resveratrol and omega-3, as well as AQP4 gene silencing lead to reduced edema upon TBI. This review summarizes current knowledge and evidence on the relationship between AQP4 and TBI, and the potential mechanisms involved.

Role of Monocyte-to-lymphocyte Ratio, Mean Platelet Volume-to-Platelet Count Ratio, C-Reactive Protein and Erythrocyte Sedimentation Rate as Predictor of Severity in Secondary Traumatic Brain Injury: A Literature Review

BACKGROUND: Secondary traumatic brain injury (TBI) is injury to the brain following primary TBI because of neuroinflammation as consequences of neuronal and glial cell injury which cause release of various inflammation cytokine and chemokine. Biomarker examination to predict the severity of secondary TBI is important to provide appropriate treatment to the patient. This article reviews possibility several common laboratory parameter such as monocyte-to-lymphocyte ratio (MLR), mean platelet volume-to-platelet count (PC) ratio (MPV-PCR), c-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) to predict severity of secondary TBI. LITERATURE REVIEW: TBI activates microglia which increase infiltration and proliferation of monocyte. Neuroinflammation also increases thrombopoiesis which leads to increase megakaryocytes production. In the other hand, due to disruption of brain blood vessels because of trauma, coagulation cascade is also activated and leads to consumptive coagulopathy. These are reflected as high monocyte count, low PC, and high MPV. Lymphocyte count is reported low in TBI especially in poor outcome patients. CRP is an acute phase reactant that increased in inflammation condition. In TBI, increased production of Interleukin-6 leads to increase CRP production. In head injured patients, ESR level does not increase significantly in the acute phase of inflammation but last longer when compared to CRP. CONCLUSION: MLR, MPV-PCR, CRP, and ESR could be predictor of severity in secondary TBI.

Effect of hypertonic saline in the management of elevated intracranial pressure in children with cerebral edema: A systematic review and meta-analysis

Objective:

To determine the hypertonic saline efficacy in children with cerebral edema and raised intracranial pressure.

Method:

Studies assessing the efficacy and safety of hypertonic saline in children with cerebral edema and elevated intracranial pressure were identified using Medline, Web of Science, Scopus, and Google Scholar databases. Two reviewers independently assessed papers for inclusion. The primary outcome was a reduction of elevated intracranial pressure by the administration of hypertonic saline.

Results:

We initially evaluated 1595 potentially relevant articles, and only 7 studies met the eligibility criteria for the final analysis. Out of the seven studies, three of them were randomized controlled trials. Three of the studies found that hypertonic saline significantly reduced elevated intracranial pressure compared to control. One study reported a resolution of the comatose state as a measure of reduced intracranial pressure. It also found a significantly higher resolution of coma in the hypertonic saline group rather than the control. Three studies reported that the reduction of intracranial pressure was comparable between the groups. The random-effects model using pooled estimates from four studies showed no difference in hypertonic saline and conventional therapy mortality outcomes. Hypertonic saline was administered as bolus-only therapy at a rate of 1–10 mL/kg/dose over 5 min to 2 h and or bolus followed by infusion therapy (0.5–2 mL/kg/h). One study reported a twofold faster resolution of high intracranial pressure following hypertonic saline administration compared to controls. The re-dosing schedule varied greatly in all included studies. However, three studies reported adverse events but not methodically, and there were no reports on neurological sequelae.

Conclusion:

Hypertonic saline appears to reduce intracranial pressure in children with cerebral edema. However, we cannot draw a firm conclusion regarding the safest dose regimens of hypertonic saline, including the safe and effective therapeutic hypernatremia threshold in the management of raised intracranial pressure with cerebral edema. Future clinical trials should focus on the appropriate concentration, dose, duration, mode of administration, and adverse effects of hypertonic saline to standardize the treatment.

Hypertonic saline buffered with sodium acetate for intracranial pressure management

BACKGROUND

3 % hypertonic saline (HS) is a hyperosmolar agent often used to treat elevated intracranial pressure (ICP). However, the resultant hyperchloremia is associated with adverse outcomes in certain patient populations. In this study, HS solution buffered with sodium acetate (HSwSA) is used as an alternative to standard 3 % formulations to reduce overall chloride exposure. Our objectives are to establish whether this alternative agent - with reduced chloride content - is similar to standard 3 % HS in maintaining hyperosmolarity and investigate its effects on hyperchloremia.

METHODS

A retrospective chart review was conducted from August 1, 2014 to August 1, 2017 on patients receiving hypertonic therapies for ICP management. Patients were categorized into three groups, those that received: (1) 3 % HS for at least 72 h, (2) HSwSA for at least 72 h, or (3) were switched from 3 % HS within 72 h of initiating therapy to HSwSA for at least 72 h.

RESULTS

The average increase in serum osmolality after 72 h of therapy was 21.1 moSm/kg for those only on 3 % HS and 20.3 mOsm/kg for those only on HSwSA. Serum chloride levels after 24 h decreased on average by 2.5 mEq/L after switching from 3% HS to HSwSA and stayed below baseline, whereas matched patients only receiving 3% HS on average had serum chloride levels increase 4.3 mEq/L after 24 h and continued to rise.

CONCLUSIONS

Hyperchloremia has been associated with decreased renal perfusion, increasing the risk of acute kidney injury and hyperchloremic metabolic acidosis. Compared to standard 3% HS, our findings suggest an alternative hyperosmolar therapy with less chloride maintains similar hyperosmolarity while reducing overall chloride exposure.

Comparison of equiosmolar doses of 10% hypertonic saline and 20% mannitol for controlling intracranial hypertention in patients with large hemispheric infarction

OBJECTIVE

We conducted this prospective self-crossover controlled trial to compare the efficacy and safety of 10 % hypertonic saline (HS) and 20 % mannitol in doses of similar osmotic burden for the treatment of increased intracranial pressure (ICP) in patients with large hemispheric infarction (LHI).

PATIENTS AND METHODS

Patients with LHI were enrolled from January 2017 to January 2018. We used an alternating treatment protocol to compare the effects of HS with mannitol given for episodes of increased ICP in patients with LHI. Indicators such as ICP, mean arterial pressure (MAP) and cerebral perfusion pressure (CPP) were continuously monitored at regular intervals for 240 min after initiation of infusion. Electrolytes, plasma osmolality and renal functions were measured before and 240 min after initiation of infusion to compare the efficacy and safety of the two drugs.

RESULTS

A total of 49 episodes of increased ICP occurred in 14 patients with LHI, of which 24 were infused with 10 % HS and 25 with 20 % mannitol. Both the treatments were equally effective in reducing ICP (P < 0.01). The differences in the duration and degree of reduction were not significant between the groups (P > 0.05). Although both the osmolar agents decreased MAP, the degree was greater in the mannitol group (P < 0.05) at T120. The increase in CPP was greater in the HS group compared with the mannitol group (P < 0.05) at T120. However, HS was associated with faster heart rate (HR) and higher serum chloride levels (P < 0.05). Changes in serum sodium levels and osmolality were not significant between the groups in spite of being higher in the HS group.

CONCLUSIONS

Both the drugs can serve as first-line agents for treating intracranial hypertension caused by LHI and should be selected rationally according to the differences in efficacy and adverse effects.

An overview of management of intracranial hypertension in the intensive care unit

Intracranial hypertension (IH) is a clinical condition commonly encountered in the intensive care unit, which requires immediate treatment. The maintenance of normal intracranial pressure (ICP) and cerebral perfusion pressure in order to prevent secondary brain injury (SBI) is the central focus of management. SBI can be detected through clinical examination and invasive and non-invasive ICP monitoring. Progress in monitoring and understanding the pathophysiological mechanisms of IH allows the implementation of targeted interventions in order to improve the outcome of these patients. Initially, general prophylactic measures such as patient's head elevation, fever control, adequate analgesia and sedation depth should be applied immediately to all patients with suspected IH. Based on specific indications and conditions, surgical resection of mass lesions and cerebrospinal fluid drainage should be considered as an initial treatment for lowering ICP. Hyperosmolar therapy (mannitol or hypertonic saline) represents the cornerstone of medical treatment of acute IH while hyperventilation should be limited to emergency management of life-threatening raised ICP. Therapeutic hypothermia could have a possible benefit on outcome. To control elevated ICP refractory to maximum standard medical and surgical treatment, at first, high-dose barbiturate administration and then decompressive craniectomy as a last step are recommended with unclear and probable benefit on outcomes, respectively. The therapeutic strategy should be based on a staircase approach and be individualized for each patient. Since most therapeutic interventions have an uncertain effect on neurological outcome and mortality, future research should focus on both studying the long-term benefits of current strategies and developing new ones.

Subdural haematomas drain into the extracranial lymphatic system through the meningeal lymphatic vessels

Subdural haematomas (SDHs) are characterized by rapidly or gradually accumulated haematomas between the arachnoid and dura mater. The mechanism of haematoma clearance has not been clearly elucidated until now. The meningeal lymphatic vessel (mLV) drainage pathway is a novel system that takes part in the clearance of waste products in the central nervous system (CNS). This study aimed to explore the roles of the mLV drainage pathway in SDH clearance and its impacting factors. We injected FITC-500D, A488-fibrinogen and autologous blood into the subdural space of mice/rats and found that these substances drained into deep cervical lymph nodes (dCLNs). FITC-500D was also observed in the lymphatic vessels (LYVE+) of the meninges and the dCLNs in mice. The SDH clearance rate in SDH rats that received deep cervical lymph vessel (dCLV) ligation surgery was significantly lower than that in the control group, as evaluated by haemoglobin quantification and MRI scanning. The drainage rate of mLVs was significantly slower after the SDH model was established, and the expression of lymphangiogenesis-related proteins, including LYVE1, FOXC2 and VEGF-C, in meninges was downregulated. In summary, our findings proved that SDH was absorbed through the mLV drainage pathway and that haematomas could inhibit the function of mLVs.

Collaborative Management Strategies for Drug Shortages in Neurocritical Care

Drug shortages have become all too familiar in the health care environment, with over 200 drugs currently on shortage. In the wake of Hurricane Maria in September 2017, hospitals across the USA had to quickly and creatively adjust medication preparation and administration techniques in light of decreased availability of intravenous (IV) bags used for compounding a vast amount of medications. Amino acid preparations, essential for compounding parenteral nutrition, were also directly impacted by the hurricane. Upon realization of the impending drug shortages, hospitals resorted to alternative methods of drug administration, such as IV push routes, formulary substitutions, or alternative drug therapies in hopes of preserving the small supply of IV bags available and prioritizing them for them most critical needs. In some cases, alternative drug therapies were required, which increased the risk of medication errors due to the use of less-familiar treatment options. Clinical pharmacists rounding with medical teams provided essential, patient-specific drug regimen alternatives to help preserve a dwindling supply while ensuring use in the most critical cases. Drug shortages also frequently occur in the setting of manufacturing delays or discontinuation and drug recalls, with potential to negatively impact patient care. The seriousness of the drug shortage crisis reached public attention by December 2017, when political and pharmacy organizations called for response to the national drug shortage crisis. In this article, we review institutional mitigation strategies in response to drug shortages and discuss downstream effects of these shortages, focusing on medications commonly prescribed in neurocritical care patients.

Fluid Overload in Pediatric Severe Traumatic Brain Injury

OBJECTIVE

Pediatric traumatic brain injury is a major public health problem in the United States. Hypertonic saline therapy is a well-established treatment in patients with severe traumatic brain injury (Glasgow Coma Scale ≤ 8) who have intracranial hypertension. In children, fluid overload is associated with increased mortality, ventilator duration, and length of PICU stay, even when controlling for severity of illness. This study reports prevalence of fluid overload in pediatric patients with severe traumatic brain injury treated with 3% hypertonic saline and effect on clinical outcomes.

DESIGN

Single-center retrospective chart review.

SETTING

PICUs at two tertiary children's hospitals.

PATIENTS

One hundred thirty-eight patients with traumatic brain injury with postresuscitation Glasgow Coma Scale less than or equal to 8 who received hypertonic saline from September 1, 2010, to February 28, 2016, and intracranial pressure monitoring and survived at least 24 hours from admission.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We used fluid balance percentage greater than or equal to 10% as our definition of fluid overload. Ninety-one percent of patients less than 1 year old had fluid overload on day 10 of admission compared with 47% of patients greater than 1 year. Fluid overloaded patients did not have increased mortality, acute kidney injury, PICU length of stay, or ventilator days. Hypertonic saline was not the cause of fluid overload in these patients.

CONCLUSIONS

Patients with severe traumatic brain injury do have high rates of fluid overload. However, fluid overload did not contribute to mortality, longer days on the ventilator, increased risk of acute kidney injury, or increased PICU length of stay.

Hyponatremia in the Neurologically Ill Patient: A Review

Hyponatremia is a well-known disorder commonly faced by clinicians managing neurologically ill patients. Neurological disorders are often associated with hyponatremia during their acute presentation and can be associated with specific neurologic etiologies and symptoms. Patients may present with hyponatremia with traumatic brain injury, develop hyponatremia subacutely following aneurysmal subarachnoid hemorrhage, or may manifest with seizures due to hyponatremia itself. Clinicians caring for the neurologically ill patient should be well versed in identifying these early signs, symptoms, and etiologies of hyponatremia. Early diagnosis and treatment can potentially avoid neurologic and systemic complications in these patients and improve outcomes. This review focuses on the causes and findings of hyponatremia in the neurologically ill patient and discusses the pathophysiology, diagnoses, and treatment strategies for commonly encountered etiologies.

The Medical Management of Cerebral Edema: Past, Present, and Future Therapies

Cerebral edema is commonly associated with cerebral pathology, and the clinical manifestation is largely related to the underlying lesioned tissue. Brain edema usually amplifies the dysfunction of the lesioned tissue and the burden of cerebral edema correlates with increased morbidity and mortality across diseases. Our modern-day approach to the medical management of cerebral edema has largely revolved around, an increasingly artificial distinction between cytotoxic and vasogenic cerebral edema. These nontargeted interventions such as hyperosmolar agents and sedation have been the mainstay in clinical practice and offer noneloquent solutions to a dire problem. Our current understanding of the underlying molecular mechanisms driving cerebral edema is becoming much more advanced, with differences being identified across diseases and populations. As our understanding of the underlying molecular mechanisms in neuronal injury continues to expand, so too is the list of targeted therapies in the pipeline. Here we present a brief review of the molecular mechanisms driving cerebral edema and a current overview of our understanding of the molecular targets being investigated.

Real-time Noninvasive Monitoring of Intracranial Fluid Shifts During Dialysis Using Volumetric Integral Phase-Shift Spectroscopy (VIPS): A Proof-of-Concept Study

BACKGROUND

Cerebral edema, which is associated with increased intracranial fluid, is often a complication of many acute neurological conditions. There is currently no accepted method for real-time monitoring of intracranial fluid volume at the bedside. We evaluated a novel noninvasive technique called "Volumetric Integral Phase-shift Spectroscopy (VIPS)" for detecting intracranial fluid shifts during hemodialysis.

METHODS

Subjects receiving scheduled hemodialysis for end-stage renal disease and without a history of major neurological conditions were enrolled. VIPS monitoring was performed during hemodialysis. Serum osmolarity, electrolytes, and cognitive function with mini-mental state examination (MMSE) were assessed.

RESULTS

Twenty-one monitoring sessions from 14 subjects (4 women), mean group age 50 (SD 12.6), were analyzed. The serum osmolarity decreased by a mean of 6.4 mOsm/L (SD 6.6) from pre- to post-dialysis and correlated with an increase in the VIPS edema index (E-Dex) of 9.7% (SD 12.9) (Pearson's correlation r = 0.46, p = 0.037). Of the individual determinants of serum osmolarity, changes in serum sodium level correlated best with the VIPS edema index (Pearson's correlation, r = 0.46, p = 0.034). MMSE scores did not change from pre- to post-dialysis.

CONCLUSIONS

We detected an increase in the VIPS edema index during hemodialysis that correlated with decreased serum osmolarity, mainly reflected by changes in serum sodium suggesting shifts in intracranial fluids.

Neurosurgery and Medical Management of Severe Head Injury

Management of the patient with moderate to severe brain injury in any environment can be time consuming and resource intensive. In the austere or hostile environment, the challenges to deliver care to this patient population are magnified. These guidelines have been developed by acknowledging commonly recognized recommendations for neurosurgical and neuro-critical care patients and augmenting those evaluations and interventions based on the experience of neurosurgeons, trauma surgeons, and intensivists who have delivered care during recent coalition conflicts.

23.4% Hypertonic Saline and Intracranial Pressure in Severe Traumatic Brain Injury Among Children: A 10-Year Retrospective Analysis

OBJECTIVE

To explore the effect of 23.4% hypertonic saline for management of elevated intracranial pressure in children admitted to our institution for severe traumatic brain injury.

DESIGN

Single-center, retrospective medical chart analysis.

SETTING

A PICU at a level 1 pediatric trauma center in the United States.

PATIENTS

Children admitted for severe traumatic brain injury from 2006 to 2016 who received 23.4% hypertonic saline and whose intracranial pressures were measured within 5 hours of receiving 23.4% hypertonic saline.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Over the 10-year period, 1,587 children were admitted for traumatic brain injury, 155 of whom were deemed severe per this study's criteria. Forty of these children received at least one dose of hypertonic saline, but 14 were excluded for insufficient intracranial pressure data. Among the remaining 26 children, one hundred one 23.4% hypertonic saline boluses were used in the analysis. Use of 23.4% hypertonic saline was associated with a decrease in intracranial pressure of approximately 7 mm Hg at both within 1 hour after the bolus (p < 0.01) and 4 hours after the bolus (p < 0.01) when compared with the intracranial pressure measured within 1 hour before the hypertonic saline bolus. These effects remained significant after adjusting for Functional Status Scale score and CT Marshall scores. There was no statistically significant association between adjunctive therapies, such as antiepileptics and analgesics, and changes in intracranial pressure. There was no laboratory evidence of hyperkalemia or renal injury after use of 23.4% hypertonic saline. Across all hospitalizations, 65% of the study population demonstrated an abnormally elevated creatinine at least once, but only three episodes of acute kidney injury occurred in total, all before hypertonic saline administration. Eight of the 26 children in this analysis died during their hospitalization. The Functional Status Scale scores ranged from 6 to 26 with a mean of 12.2 and SD of 5.7.

CONCLUSIONS

Use of 23.4% hypertonic saline with children admitted for severe traumatic brain injury is associated with a statistically significant decrease in intracranial pressure within 1 hour of use.

Therapeutic hypernatremia management during continuous renal replacement therapy with elevated intracranial pressures and respiratory failure

Cerebral edema and elevated intracranial pressure (ICP) are common complications of acute brain injury. Hypertonic solutions are routinely used in acute brain injury as effective osmotic agents to lower ICP by increasing the extracellular fluid tonicity. Acute kidney injury in a patient with traumatic brain injury and elevated ICP requiring renal replacement therapy represents a significant therapeutic challenge due to an increased risk of cerebral edema associated with intermittent conventional hemodialysis. Therefore, continuous renal replacement therapy (CRRT) has emerged as the preferred modality of therapy in this patient population. We present our current treatment approach, with demonstrative case vignette illustrations, utilizing hypertonic saline protocols (3% sodium-chloride or, with coexisting severe combined metabolic and respiratory acidosis, with 4.2% sodium-bicarbonate) in conjunction with the CRRT platform, to induce controlled hypernatremia of approximately 155 mEq/L in hemodynamically unstable patients with acute kidney injury and elevated ICP due to acute brain injury. Rationale, mechanism of activation, benefits and potential pitfalls of the therapy are reviewed. The impact of hypertonic citrate solution during regional citrate anticoagulation is specifically discussed. Maintaining plasma hypertonicity in the setting of increased ICP and acute kidney injury could prevent the worsening of ICP during renal replacement therapy by minimizing the osmotic gradient across the blood-brain barrier and maximizing cardiovascular stability.

Acute Ischemic Stroke

Acute ischemic stroke is a major cause of mortality and morbidity in the United States and worldwide. Despite the development of specialized stroke centers, mortality and morbidity as a result of acute ischemic strokes can and do happen anywhere. These strokes are emergency situations requiring immediate intervention. This article covers the fundamentals of care involved in treating patients with acute ischemic stroke, including essentials for the initial evaluation, basic neuroimaging, reperfusion therapies, critical care management, and palliative care, as well as current controversies. National guidelines and current research are presented, along with recommendations for implementation.

Management of Intracranial Pressure: Part I: Pharmacologic Interventions

Dangerous, sustained elevation in intracranial pressure (ICP) is a risk for any patient following severe brain injury. Intracranial pressure elevations that do not respond to initial management are considered refractory to treatment, or rICP. Patients are at significant risk of secondary brain injury and permanent loss of function resulting from rICP. Both nonpharmacologic and pharmacologic interventions are utilized to intervene when a patient experiences either elevation in ICP or rICP. In part 1 of this 2-part series, pharmacologic interventions are discussed. Opioids, sedatives, osmotic diuretics, hypertonic saline solutions, and barbiturates are drug classes that may be used in an attempt to normalize ICP and prevent secondary injury. Nursing care of these patients includes collaboration with an interprofessional team and is directed toward patient and family comfort. The utilization of an evidence-based guideline for the management of rICP is strongly encouraged to improve patient outcomes.

Immunohistochemical Evaluation of Aquaporin-4 and its Correlation with CD68, IBA-1, HIF-1α, GFAP, and CD15 Expressions in Fatal Traumatic Brain Injury

Traumatic brain injury (TBI) is one of the leading causes of death and disability worldwide. Our understanding of its pathobiology has substantially increased. Following TBI, the following occur, edema formation, brain swelling, increased intracranial pressure, changes in cerebral blood flow, hypoxia, neuroinflammation, oxidative stress, excitotoxicity, and apoptosis. Experimental animal models have been developed. However, the difficulty in mimicking human TBI explains why few neuroprotective strategies, drawn up on the basis of experimental studies, have translated into improved therapeutic strategies for TBI patients. In this study, we retrospectively examined brain samples in 145 cases of death after different survival times following TBI, to investigate aquaporin-4 (AQP4) expression and correlation with hypoxia, and neuroinflammation in human TBI. Antibodies anti-glial fibrillary acid protein (GFAP), aquaporin-4 (AQP4), hypoxia induced factor-1α (HIF-1α), macrophage/phagocytic activation (CD68), ionized calcium-binding adapter molecule-1 (IBA-1), and neutrophils (CD15) were used. AQP4 showed a significant, progressive increase between the control group and groups 2 (one-day survival) and 3 (three-day survival). There were further increases in AQP4 immunopositivity in groups 4 (seven-day survival), 5 (14-dayssurvival), and 6 (30-day survival), suggesting an upregulation of AQP4 at 7 to 30 days compared to group 1. GFAP showed its highest expression in non-acute cases at the astrocytic level compared with the acute TBI group. Data emerging from the HIF-1α reaction showed a progressive, significant increase. Immunohistochemistry with IBA-1 revealed activated microglia starting three days after trauma and progressively increasing in the next 15 to 20 days after the initial trauma. CD68 expression demonstrated basal macrophage and phagocytic activation mostly around blood vessels. Starting from one to three days of survival after TBI, an increase in the number of CD68 cells was progressively observed; at 15 and 30 days of survival, CD68 showed the most abundant immunopositivity inside or around the areas of necrosis. These findings need to be developed further to gain insight into the mechanisms through which brain AQP4 is upregulated. This could be of the utmost clinicopathological importance.

A dose-response relationship study of hypertonic saline on brain relaxation during supratentorial brain tumour craniotomy

Background: A prospective, randomized, double-blind study was designed to assess differences in brain relaxation between 2 doses of 3% HS during elective supratentorial brain tumour surgery.Methods: 60 patients undergoing supratentorial craniotomy for tumour resection were enrolled to receive either 3 mL/kg (group L) or 5 mL/kg (group H) of 3% HS administered at skin incision. Brain relaxation was assessed after dura opening on a scale ranging 1-4 (1 = perfectly relaxed, 2 = satisfactorily relaxed, 3 = firm brain, 4 = bulging brain). Hemodynamic variables and laboratory values (blood gases, osmolarity, haematocrit, and lactate) were collected before HS infusion and 30, 120 and 360 min after it. Presence of midline shift, postoperative complications, PCU and hospital stay, and mortality after 30 days were also recorded.Results: There was no difference in brain relaxation, with 2.0 (1.0-3.0) and 2.0 (1.0-2.3) (P = 0.535) for patients in groups L and H, respectively. If adjusted for the presence of midline shift, 50% of patients had adequate brain relaxation scores (grades 1 and 2) in group L and 61% in group H (OR 0.64, CI = 0.16-2.49, P = 0.515). No significant differences in perioperative outcome, mortality and length of PCU and hospital stay were observed.Conclusion: 3 mL/kg of 3% HS result in similar brain relaxation scores as 5 mL/kg in patients undergoing craniotomy for supratentorial brain tumour. This study reveals that both high and low doses of 3% HS may be less effective on intraoperative brain relaxation in patients with midline shift.

Fluid Management in Acute Brain Injury

PURPOSE OF THE REVIEW

The aims of fluid management in acute brain injury are to preserve or restore physiology and guarantee appropriate tissue perfusion, avoiding potential iatrogenic effects. We reviewed the literature, focusing on the clinical implications of the selected papers. Our purposes were to summarize the principles regulating the distribution of water between the intracellular, interstitial, and plasma compartments in the normal and the injured brain, and to clarify how these principles could guide fluid administration, with special reference to intracranial pressure control.

RECENT FINDINGS

Although a considerable amount of research has been published on this topic and in general on fluid management in acute illness, the quality of the evidence tends to vary. Intravascular volume management should aim for euvolemia. There is evidence of harm with aggressive administration of fluid aimed at achieving hypervolemia in cases of subarachnoid hemorrhage. Isotonic crystalloids should be the preferred agents for volume replacement, while colloids, glucose-containing hypotonic solutions, and other hypotonic solutions or albumin should be avoided. Osmotherapy seems to be effective in intracranial hypertension management; however, there is no clear evidence regarding the superiority of hypertonic saline over mannitol. Fluid therapy plays an important role in the management of acute brain injury patients. However, fluids are a double-edged weapon because of the potential risk of hyper-hydration, hypo- or hyper-osmolar conditions, which may unfavorably affect the clinical course and the outcome.

Traumatic Brain Injury in the Pediatric Intensive Care Unit

Head trauma is a leading cause of brain injury in children, and it can have profound lifelong physical, cognitive, and behavioral consequences. Optimal acute care of children with traumatic brain injury (TBI) requires rapid stabilization and early neurosurgical evaluation by a multidisciplinary team. Meticulous attention is required to limit secondary brain injury after the initial trauma. This review discusses pathophysiology, acute stabilization, and monitoring, as well as supportive and therapeutic measures to help minimize ongoing brain injury and optimize recovery in children with TBI. [Pediatr Ann. 2018;47(7):e274-e279.].

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

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

Management of Acute Liver Failure: A Pediatric Perspective

Purpose of Review

Pediatric acute liver failure is a rare, complex, rapidly progressing, and life-threatening illness. Majority of pediatric acute liver failures have unknown etiology. This review intends to discuss the current literature on the challenging aspects of management of acute liver failure.

Recent Findings

Collaborative multidisciplinary approach for management of patients with pediatric acute liver failure with upfront involvement of transplant hepatologist and critical care specialists can improve outcomes of this fatal disease. Extensive but systematic diagnostic evaluation can help to identify etiology and guide management. Early referral to a transplant center with prompt liver transplant, if indicated, can lead to improved survival in these patients.

Summary

Prompt identification and aggressive management of pediatric acute liver failure and related comorbidities can lead to increased transplant-free survival and improved post-transplant outcomes, thus decreasing mortality and morbidity associated with this potential fatal condition.

Intravenous Hypertonic Saline to Lower Intraocular Pressure in Ocular Hypertension and Primary Open-angle and Exfoliation Glaucoma

PURPOSE

The purpose of this article was to quantitate the effect of intravenous hypertonic saline (IVHTS) on elevated intraocular pressure (IOP) among 3 groups of glaucoma patients or suspects.

MATERIALS AND METHODS

Among the forty-four patients with IOP 24 to 30 mm Hg included in this study, 13 had ocular hypertension (OHT), 14 primary open-angle glaucoma (POAG), and 17 exfoliation glaucoma (ExG). Participants received a bolus of 23.4% IVHTS (1.0 mmol/kg) through an antecubital vein. We measured IOP, heart rate, and blood pressure before the bolus, thereafter every minute for 10 minutes, and less frequently for 2 hours.

RESULTS

The median baseline IOP was 24 mm Hg (range, 24 to 30 mm Hg), 26.5 mm Hg (range, 24 to 30 mm Hg), and 26 mm Hg (range, 24 to 30 mm Hg) in OHT, POAG, and ExG patients, respectively. Sixteen minutes after the bolus, IOP was a median of 9 mm Hg (range, 4 to 12 mm Hg), 10 mm Hg (range, 6 to 12 mm Hg), and 10 mm Hg (range, 4 to 14 mm Hg) lower in OHT, POAG, and ExG groups (P=0.70), respectively. After 1 hour, the median IOP reduction was similar between ExG (9 mm Hg; range, 4 to 14 mm Hg) and POAG patients (9.5 mm Hg; range, 6 to 12 mm Hg) but lower in OHT patients (6 mm Hg; range, 2 to 9 mm Hg; P=0.006). Heart rate decreased by a median of 7 beats/min. Blood pressure increased within 3 minutes (median, mm Hg; 15 systolic; 5 diastolic), but returned to baseline at 10 minutes. Within 1 to 3 minutes of treatment, 36 (82%) patients felt pain in the infusion arm, and 29 (66%) reported a feeling of warmth in their head.

CONCLUSIONS

IVHTS reduced IOP effectively in all groups.

Osmotherapy With Hypertonic Saline Attenuates Global Cerebral Edema Following Experimental Cardiac Arrest via Perivascular Pool of Aquaporin-4

OBJECTIVES

We tested the hypothesis that osmotherapy with hypertonic saline attenuates cerebral edema following experimental cardiac arrest and cardiopulmonary resuscitation by exerting its effect via the perivascular pool of aquaporin-4. We used mice with targeted disruption of the gene encoding α-syntrophin (α-Syn) that demonstrate diminished perivascular aquaporin-4 pool but retain the non-endfoot and ependymal pools.

DESIGN

Laboratory animal study.

SETTING

University animal research laboratory.

INTERVENTIONS

Isoflurane-anesthetized adult male wild-type C57B/6 or α-Syn mice were subjected to cardiac arrest/cardiopulmonary resuscitation and treated with either a continuous IV infusion of 0.9% saline or various concentrations of hypertonic saline. Serum osmolality, regional brain water content, blood-brain barrier disruption, and aquaporin-4 protein expression were determined at 24 hours after cardiac arrest/cardiopulmonary resuscitation.

MEASUREMENTS AND MAIN RESULTS

Hypertonic saline (7.5%) treatment significantly attenuated water content in the caudoputamen complex and cortex compared with 0.9% saline treatment in wild-type mice subjected to cardiac arrest/cardiopulmonary resuscitation. In contrast, in α-Syn mice subjected to cardiac arrest/cardiopulmonary resuscitation, 7.5% hypertonic saline treatment did not attenuate water content. Treatment with 7.5% hypertonic saline attenuated blood-brain barrier disruption at 24 hours following cardiac arrest/cardiopulmonary resuscitation in wild-type mice but not in α-Syn mice. Total aquaporin-4 protein expression was not different between 0.9% saline and hypertonic saline-treated wild-type mice.

CONCLUSIONS

Following experimental cardiac arrest/cardiopulmonary resuscitation: 1) continuous hypertonic saline therapy maintained to achieve serum osmolality of ≈ 350 mOsm/L is beneficial for the treatment of cerebral edema; 2) perivascular pool of aquaporin-4 plays a critical role in water egress from brain; and 3) hypertonic saline attenuates blood-brain barrier disruption via perivascular aquaporin-4 pool.

Intensive Care Management of Pediatric Acute Liver Failure

Pediatric acute liver failure is rare but life-threatening illness that occurs in children without preexisting liver disease. The rarity of the disease, along with its severity and heterogeneity, presents unique clinical challenges to the physicians providing care for pediatric patients with acute liver failure. In this review, practical clinical approaches to the care of critically ill children with acute liver failure are discussed with an organ system-specific approach. The underlying pathophysiological processes, major areas of uncertainty, and approaches to the critical care management of pediatric acute liver failure are also reviewed.

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.