Hypertonic saline versus mannitol for brain relaxation in supratentorial tumor surgery: a prospective randomized...

Hypertonic saline and mannitol are widely used to improve brain relaxation during supratentorial mass surgeries. Although continuous administration of hypertonic saline is known to reduce intracranial pressure, it has not yet been evaluated in supratentorial mass surgeries.

After institutional ethical committee approval, 92 patients scheduled for supratentorial craniotomy with glioblastoma multiforme, metastasis and/or midline shift (> 0.5 cm) were enrolled into this prospective, randomized, and double-blind study. The patients received hypertonic saline 3 mL.kg^-1 bolus, hypertonic saline infusion 20 mL.h^-1 or 20 % mannitol 0.6 gr.kg^-1 after head positioning. Brain relaxation score (1 = Perfectly relaxed, 2 = Satisfactorily relaxed, 3 = Firm brain and 4 = Bulging brain) was the primary outcome. Sodium and chlorine levels were the secondary outcomes. Postoperative brain edema and midline shift were assessed.

After randomization, two patients were excluded from the study. Brain relaxation scores were higher with hypertonic saline bolus compared to mannitol (p = 0.047). The effect size between groups for brain relaxation score was 0.22. Hypertonic saline continuous infusion and mannitol were similar with respect to brain relaxation scores. Sodium and chlorine levels were lower in the mannitol group. Postoperative midline shift and edema were lower with continuous hypertonic saline compared to other groups (p = 0.001, p = 0.006).

Continuous infusion of 3 % hypertonic saline was associated with better relaxation scores in the intraoperative period and with lower incidences of edema/midline shift in the postoperative period of supratentorial mass surgeries with glioblastoma multiforme, metastasis and/or midline shift.