A traumatic insult to the brain causes disruption of the blood-brain barrier (BBB) and cellular injury, followed by the infiltration of inflammatory cells. These cytokines induce nitric oxide production causing vasodilation and failure of cerebral pressure auto regulation, which further causes cerebral blood flow in the injured region to become dependent on CPP, which is reduced by systemic hypotension and therefore demands correction and prevention.

Hypotension in TBI patients can be due to hemorrhage, third-space fluid losses, and vasoplegia. Additionally, as polytrauma is common in patients with TBI, multiorgan damage can result in hypoxemia, hypovolemia, and systemic inflammation which can cause secondary insult to injured brain tissue thus complicating the approach to treatment.

The mainstay of fluid resuscitation from hypovolemia remains Intravenous (IV) fluid therapy. Fluid may be balanced, buffered, isotonic crystalloid (e.g., Plasma-Lyte, Normosol-R), an isotonic crystalloid with a higher sodium concentration (0.9% sodium chloride), hypertonic saline (HTS 3–7.5%), and/or a synthetic or natural colloid. 

However, hyponatremic fluids [e.g., lactated Ringer′s solution (LRS)] must be reserved for only hyponatremic patients as they tend to produce an increased osmolar gap that could favour brain water accumulation.

There come controversial recommendations from The Brain Trauma Foundation (BTF) and The Lund Concept for the treatment of TBI. The BTF interventions sets upon evidence-based recommendations gleaned having their foundation on the literature review of published studies. However, this guideline does not make any recommendations about the use of any specific fluid type. 

While The Lund Concept summarizes non-individualized, pre-emptive, ICP-regulating and perfusion-targeted therapy for manipulating transcapillary fluid dynamics utilizing albumin (in addition to vasodilators and avoiding the use of vasopressors). However, this guideline lacks strong evidence supporting the protocol.

A combination that deserves discussion is HTS containing adenosine, lidocaine, and magnesium. This combination has demonstrated a protective role in numerous life-threatening conditions in animal models of sepsis, non-compressible hemorrhagic shock, and TBI from non-compressible hemorrhage.

Source: Front Vet Sci. 2021;8:643800. Published 2021 Jul 9. doi:10.3389/fvets.2021.643800