Abstract
BACKGROUND: Current guidelines identify the choice of fluid resuscitation as important in minimizing the incidence of secondary brain injury from cerebral edema. It is widely accepted that isotonic crystalloid resuscitation fluids, specifically normal saline (NS), are optimal for resuscitation and that other relatively hypotonic fluids, such as Ringer's lactate (RL), should be avoided in this patient population. The aim of this review is to systematically compare the use of relatively hypotonic versus isotonic crystalloid resuscitation fluids in clinical and pre-clinical models of acute brain injury and their effect on outcomes. In recognition of the potential need for a network meta-analysis (NMA), we have also included all other relevant crystalloid resuscitation fluids as interventions of relevance to potentially inform indirect comparisons. METHODS: Systematic searches of MEDLINE, Embase, and Web of Science BIOSIS Previews® will be used to identify eligible clinical and pre-clinical studies, which included studies examining acute brain injury (human and in vivo animal brain injury models) within the first 7 days of therapy. The intervention of interest is the intravenous use of relatively hypotonic crystalloid resuscitation fluids (e.g., Ringer's lactate, Hartmann's or Plasma Lyte® fluids). The main comparator of interest is an isotonic crystalloid resuscitation fluid, specifically normal saline (0.9%). Other crystalloid resuscitation fluids (e.g., hypertonic saline (3-23.4%)) will also be included as an additional intervention of interest. The primary outcome measures of interest are intracranial pressure (ICP) and cerebral perfusion pressure (CPP). Secondary outcomes include the effect of resuscitation on cerebral edema, brain and serum osmolarity, and electrolyte concentrations and clinical outcomes including modified Rankin Scale (mRS), (extended) Glasgow Outcome Scale (GOS/eGOS), and mortality. Separate meta-analyses will be conducted to quantify the effects of the different fluid resuscitation on acute brain injury outcomes in clinical and pre-clinical populations. Network meta-analyses to compare interventions will also be performed to compare the effects of different interventions. DISCUSSION: This systematic review will comprehensively summarize the difference in treatment efficacy of various crystalloid resuscitation fluids in acute brain injury. This review is essential to underscore the evidence, or lack thereof, present in the literature to date to support current preference-driven practice and to direct future study. SYSTEMATIC REVIEW REGISTRATION: PROSPERO #CRD42016042960.