Emergency Neurological Life Support: Subarachnoid Hemorrhage

Aneurysmal Subarachnoid Hemorrhage: Review of the Pathophysiology and Management Strategies

PURPOSE OF REVIEW

Aneurysmal subarachnoid hemorrhage remains a devastating disease process despite medical advances made over the past 3 decades. Much of the focus was on prevention and treatment of vasospasm to reduce delayed cerebral ischemia and improve outcome. In recent years, there has been a shift of focus onto early brain injury as the precursor to delayed cerebral ischemia. This review will focus on the most recent data surrounding the pathophysiology of aneurysmal subarachnoid hemorrhage and current management strategies.

RECENT FINDINGS

There is a paucity of successful trials in the management of subarachnoid hemorrhage likely related to the targeting of vasospasm. Pathophysiological changes occurring at the time of aneurysmal rupture lead to early brain injury including cerebral edema, inflammation, and spreading depolarization. These events result in microvascular collapse, vasospasm, and ultimately delayed cerebral ischemia. Management of aneurysmal subarachnoid hemorrhage has remained the same over the past few decades. No recent trials have resulted in new treatments. However, our understanding of the pathophysiology is rapidly expanding and will advise future therapeutic targets.

Low-chloride versus high-chloride hypertonic solution for the treatment of subarachnoid hemorrhage-related complications (The ACETatE trial): study protocol for a pilot randomized controlled trial

Background

Aneurysmal subarachnoid hemorrhage (aSAH) is a life-threatening condition that results from a ruptured cerebral vessel. Cerebral edema and vasospasm are common complications and frequently require treatment with hypertonic solutions, in particular hypertonic sodium chloride (NaCl). We have previously shown that hyperchloremia in patients with aSAH given hypertonic NaCl is associated with the development of acute kidney injury (AKI), which leads to higher morbidity and mortality. Our current trial aims to study the effect of two hypertonic solutions with different chloride content on serum chloride concentrations in patients with aSAH who are at risk for AKI.

Methods

A low ChloridE hyperTonic solution for brain Edema (ACETatE) is a single center, double-blinded, double-dummy pilot trial comparing bolus doses of 23.4% NaCl and 16.4% NaCl/Na-Acetate for the treatment of cerebral edema in patients with aSAH. All patients will be enrolled within 36 h following admission. Randomization will occur once patients who receive hypertonic treatment for cerebral edema develop hyperchloremia (serum Cl⁻ concentration ≥ 109 mmol/L). Subsequent treatment will consist of either NaCl 23.4% or NaCl/Na-Acetate 16.4%. The primary outcome of this study will be the change in serum Cl⁻ concentrations during treatment. Secondary outcomes will include incidence of AKI, mortality, changes in intracranial pressure, and extent of hypernatremia.

Discussion

In patients with aSAH, hyperchloremia is a known risk factor for subsequent development of AKI. The primary goal of this pilot study is to determine the effect of two hypertonic solutions with different Cl⁻ content on serum Cl⁻ concentrations in patients with aSAH who have already developed hyperchloremia. Data will be collected prospectively to determine the extent to which the choice of hypertonic saline solution affects subsequent serum Cl⁻ concentrations and the occurrence of AKI. This approach will allow us to obtain preliminary data to design a large randomized trial assessing the effects of chloride-sparing hypertonic solutions on development of AKI in patients with SAH. This pilot study is the first to prospectively evaluate the relationship between hypertonic solution chloride content and its effect on serum electrolytes and renal function in aSAH patients at risk of AKI due to hyperchloremia.

Trial registration

Clinicaltrials.gov, NCT03204955. Registered on 28 June 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-3007-7) contains supplementary material, which is available to authorized users.

Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is a neurological emergency with high risk of neurological decline and death. Although the presentation of a thunderclap headache or the worst headache of a patient's life easily triggers the evaluation for SAH, subtle presentations are still missed. The gold standard for diagnostic evaluation of SAH remains noncontrast head computed tomography (CT) followed by lumbar puncture if the CT is negative for SAH. Management of patients with SAH follows standard resuscitation of critically ill patients with the emphasis on reducing risks of rebleeding and avoiding secondary brain injuries.