Comparison of Effects of Equiosmolar Doses of Mannitol and Hypertonic Saline on Cerebral Blood Flow and Metabolism in Traumatic Brain Injury

Abstract

The potential superiority of hypertonic saline (HTS) over mannitol (MTL) for control of intracranial pressure (ICP) following traumatic brain injury (TBI) is still debated. Forty-seven severe TBI patients with increased ICP were prospectively recruited in two university hospitals and randomly treated with equiosmolar infusions of either MTL 20% (4 mL/kg; n=25 patients) or HTS 7.5% (2 mL/kg; n=22 patients). Serum sodium, hematocrit, ICP, arterial blood pressure, cerebral perfusion pressure (CPP), shear rate, global indices of cerebral blood flow (CBF) and metabolism were measured before, and 30 and 120 min following each infusion during the course of illness. Outcome was assessed at 6 months. Both HTS and MTL effectively and equally reduced ICP levels with subsequent elevation of CPP and CBF, although this effect was significantly stronger and of longer duration after HTS and correlated with improved rheological blood properties induced by HTS. Further, effect of HTS on ICP appeared to be more robust in patients with diffuse brain injury. In contrast, oxygen and glucose metabolic rates were left equally unaffected by both solutions. Accordingly, there was no significant difference in neurological outcome between the two groups. In conclusion, MTL was as effective as HTS in decreasing ICP in TBI patients although both solutions failed to improved cerebral metabolism. HTS showed an additional and stronger effect on cerebral perfusion of potential benefit in the presence of cerebral ischemia. Treatment selection should therefore be individually based on sodium level and cerebral hemodynamics.

Hypertonic saline in severe traumatic brain injury: a systematic review and meta-analysis of randomized controlled trials

“…[27][28][29][30][31][32][33][34][35][36][37] All studies were published in English. Of the 11 studies, only 3 included more than 100 patients 27,31,32 ( Table 1).…”

“…Of the 11 studies, only 3 included more than 100 patients 27,31,32 ( Table 1). All studies specified adult population; however, three studies defined adult population as 16 years of age and older, 27,30,33 and one study as 15 years of age and older. 31 One study randomized intracranial hypertension episodes, instead of randomizing patients.…”

“…30 In one study, three patients (0.01% of our total population) with stroke were also included, which represented less than 15% of that study's patient population. 34 Three comparators were identified: hyperosmolar solution (mannitol or sodium bicarbonate), 28,[33][34][35]37 iso-osmolar solution (normal saline or ringer's lactate), 27,31,32 and hypo-osmolar solution 36 (see Table 1). …”

“…In general, allocation concealment was respected in most studies (63%), 27,[30][31][32][33][34][35] and the randomization method was specified in slightly more than half of them (54%). 27,[31][32][33]35,36 In six studies (63%), the research staff, patients, and medical staff were not blinded to the intervention studied.…”

“…27,[31][32][33]35,36 In six studies (63%), the research staff, patients, and medical staff were not blinded to the intervention studied. 27,28,30,33,34,37 The information regarding blinding was missing in three studies (27%).…”