Brain-relaxing effect of different diuretic regimens in supratentorial tumor surgery: A comparative study guided by optic nerve sheath diameter

Background: Hyperosmolar therapy is a well-established method to approach brain relaxation during craniotomy. Mannitol is used with a wide range of dosing regimens, combination with loop diuretics exerts a synergistic effect resulting in both reduction of the dose and its complications. Ultrasound measurement of optic nerve sheath diameter (ONSD) gives reliable information about intracranial pressure (ICP) and avoids overdosing and complications of osmotherapy. Aims and Objectives: In this study, we compare the ordinary dose of mannitol with the low dose combined with furosemide and detect the effect on ICP by ONSD. Setting and Design: This is a prospective, randomized, double-blind study involving 60 patients undergoing supratentorial brain tumor surgery. Materials and Methods: Sixty patients were enrolled in this study, divided into two equal groups: Group M received mannitol 1 g.kg−1: while Group F received mannitol 0.25 g.kg−1 and furosemide 0.5 mg.kg−1. Reduction in ONSD measurement was the primary objective, while brain-relaxation score (BRS), hemodynamic changes, urine output, serum lactate, and changes in serum electrolyte were the secondary objectives. Statistical Analysis: Data collected were analyzed using SPSS software, IBM, USA, version 22. P value was considered significant if <0.05. Results: ONSD and BRS showed no statistically significant difference between the studied groups. After diuresis, Group M showed significant reduction in heart rate and mean arterial blood pressure, serum sodium, potassium, and lactate (P = 0.02, P = 0.02, P = 0.001, P = 0.001, P = 0.001, P = 0.001 respectively), with increased urine output (UOP) and fluids replacement (P = 0.00, P = 0.01, respectively). Conclusion: Compared to high dose, adding loop diuretics to low-dose mannitol during supratentorial brain tumor surgeries resulted in comparable BRSs with a lower incidence of hemodynamic and metabolic disturbances.