Hypertonic Solutions in Traumatic Brain Injury: A Systematic Review and Meta-Analysis

Hyperosmolar therapies for neurological deterioration in mild and moderate traumatic brain injury: A scoping review

OBJECTIVE

To explore the available evidence on hyperosmolar therapies(HT) in mild and moderate traumatic brain injury(TBI) and to evaluate the effects on outcomes.A scoping review was conducted according to the Joanna Briggs Institute methodology. Inclusion criteria: (a)randomized controlled trials(RCTs), prospective and retrospective cohort studies and case-control studies; (b)all-ages mild and moderate TBIs; (c)HT administration; (d)functional outcomes recorded; (e)comparator group.

RESULTS

From 4424 records, only 3 respected the inclusion criteria. In a retrospective cohort study of adult moderate TBIs, the Glasgow Coma Scale(GCS) remained the same at 48 hours in those treated with hypertonic saline(HTS) while it worsened in the non-treated. A trend toward increased pulmonary infections and length of stay was found. In an RCT of adult severe and moderate TBIs, moderate TBIs treated with HTS showed a trend toward better secondary outcomes than standard care alone, with similar odds of adverse effects. An RCT enrolling children with mild TBI found a significant improvement in concussive pain immediately after HTS administration and after 2-3 days. No adverse events occurred.

CONCLUSIONS

A gap in the literature about HTs' role in mild and moderate TBI was found. Some benefits may exist with limited side effects and further studies are desirable.

Terms, Definitions, Nomenclature, and Routes of Fluid Administration

Fluid therapy is administered to veterinary patients in order to improve hemodynamics, replace deficits, and maintain hydration. The gradual expansion of medical knowledge and research in this field has led to a proliferation of terms related to fluid products, fluid delivery and body fluid distribution. Consistency in the use of terminology enables precise and effective communication in clinical and research settings. This article provides an alphabetical glossary of important terms and common definitions in the human and veterinary literature. It also summarizes the common routes of fluid administration in small and large animal species.

High Versus Low Volume Fluid Resuscitation Strategies in a Porcine Model (Sus scrofa) of Combined Thermal and Traumatic Brain Injury

BACKGROUND

Combined burn and traumatic brain injury (TBI) treatment priorities may not align due to opposing fluid resuscitation paradigms used in treating burns and TBI. We developed a porcine model of combined thermal injury/TBI and compared an "aggressive" fluid resuscitation strategy using the Parkland formula and a "restrictive" resuscitation strategy using the modified Brooke formula.

METHODS

Twenty-eight swine were deeply anesthetized and received a 40% total body surface area full-thickness burn injury and TBI. Swine were then randomized to receive restrictive or aggressive resuscitation for 8 h after which time animals were euthanized and necropsy was performed. Volume of brain injury was assessed after analyzing segmental slices of brain tissue.

RESULTS

There were no differences between the restrictive and aggressive resuscitation groups in blood pressure, heart rate, central venous pressure, intra-cranial pressure (ICP), or serum lactate levels after 8 h of resuscitation. Urine output was higher in the aggressive resuscitation group. The restrictive group had a significantly higher serum blood urea nitrogen (BUN) compared with baseline and compared with the aggressive group. There was no significant difference in size of brain injury between groups.

CONCLUSIONS

Both restrictive and aggressive resuscitation demonstrated adequate resuscitation at 8 h postinjury. Increased serum BUN in the restrictive group may be an indicator of early acute kidney injury, despite adequate urine output. Resuscitation strategy did not appear to affect ICP or the size of brain injury.

Comparative Radiographic Factors Predicting Functional Outcome After Decompressive Craniectomy in Severe Traumatic Brain Injury

OBJECTIVES

Decompressive craniectomy (DC) is a last-tier therapy in the treatment of raised intracranial pressure after traumatic brain injury (TBI). We report the association of comparative radiographic factors in predicting functional outcomes after DC in patients with severe TBI.

METHODS

A retrospective analysis of a prospectively maintained database of cases between 2015 and 2018 at an academic tertiary care hospital was carried out. Univariate and multivariable regression analyses were performed for an array of comparative radiographic variables (pre- and post-DC) in relationship to functional outcome according to Glasgow Outcome Scale Extended (GOSE) at 180 days. GOSE was further dichotomized into favorable (GOSE:5-8) and unfavorable (GOSE:0-4) functional outcomes. All associations were reported as odds ratio (OR) with 95% confidence interval (CI).

RESULTS

Statistical analysis included a cohort of 43 patients with a median age of 30.5 years (range: 18-62 years). The median GOSE at 180 days was 7. Multivariable regression analysis after adjusting for confounding variables (age, sex, comorbidities, site of surgery and size of decompression) showed that comparative radiographic findings of midline shift (MLS) > 10 mm (OR 3.2 (95% CI 1.25-8.04); P = 0.01); external cerebral herniation (ECH) > 2.5 cm (OR 2.5 [95% CI 1.18-5.2]; P = 0.02); and effacement of basal cisterns (OR 3.9 [95%CI 1.1-13.9]; P = 0.03), were significant independent predictors of poor functional outcome at 180 days after DC for severe TBI. However, the presence of infarction (OR 2.7 [95%CI 0.43-17.2]; P = 0.28) and absence of gray-white matter differentiation (OR 0.18 [95%CI 0.03-1.2]; P = 0.07) did not reach statistical significance.

CONCLUSIONS

The comparative radiographic findings that include MLS > 10mm, ECH > 2.5cm, and effacement of basal cisterns are predictive of poor functional outcome in severe TBI.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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