Comparison of utilizing a hypertonic saline solution and mannitol to improve brain relaxation during craniotomy in patients with brain tumours: a prospective randomized controlled trial

Hyperosmolar therapy, specifically the use of mannitol, has been employed to improve brain relaxation, but mannitol use may cause hypovolemia and electrolyte imbalance. Given these risks, hypertonic saline was introduced as an alternative; however, data on its efficacy and safety are limited. Researchers conducted a prospective, double-blind, randomized controlled trial. Sixty-six patients with supratentorial or posterior fossa brain tumours undergoing craniotomy were randomized into two groups. Group M received 20% mannitol at 3 ml/kg, and Group H received 3% hypertonic saline at the same dose. These solutions were administered before dural opening. Two masked neurosurgeons immediately assessed the four-point brain relaxation score by direct visual and tactile evaluation after dural opening. Both groups showed no significant difference in brain relaxation scores (p = 0.543). There was no significant difference in haemodynamic change, fluid replacement, or serum osmolarity between groups; however, urine output was greater in the mannitol group (p = 0.003). Additionally, postoperative neurological outcomes and one-month mortality rates were similar. These findings suggest 3% hypertonic saline can be considered an alternative to mannitol for improving brain relaxation during craniotomy, as it is equally effective with less urine output.