Comparison of Two Doses of Mannitol on Brain Relaxation During Supratentorial Craniotomy
80 patients will be divided in two equal groups (Group 1: to receive 20% mannitol 0.7 g/kg
or Group 2: 1.4 g/kg).
The anesthetic technique and monitoring will be standardized. The administration of
mannitol will start following the induction of general anesthesia. The infusion will be
given intravenously over 30 minutes.
Brain relaxation will be assessed by a senior surgeon at the opening of the dura mater on a
scale from 1 to 4 (1= perfectly relaxed, 2= satisfactorily relaxed, 3= firm brain, 4=bulging
If needed, in case of significant cerebral edema, a rescue dose of 20% mannitol 0.25 g/kg
will be administered.
Hemodynamic variables (MAP, heart rate), temperature, urine output, perioperative fluid
balance, blood loss and laboratory values (blood gases, electrolytes, osmolality,
hematocrit, glycemia, lactates) will be collected immediately prior to the infusion of
mannitol and at 30, 60, 180 minutes following the administration of mannitol.
The type of cerebral lesion, its location and size (in 3 dimensions) will be noted. The
presence of a median-line shift will also be assessed.
Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Outcomes Assessor), Primary Purpose: Treatment
Brain relaxation at the opening of the dura mater assessed by a senior surgeon on a scale from 1 to 4 (1= perfectly relaxed, 2= satisfactorily relaxed, 3= firm brain, 4=bulging brain)
At the opening of the dura mater
François Girard, MD, FRCPC
Centre hospitalier de l'Université de Montréal (CHUM)
Canada: Ethics Review Committee