Clinical effectiveness of hypertonic sodium lactate infusion for intraoperative brain relaxation in patients undergoing scheduled craniotomy for supratentorial brain tumor resection: A study protocol of a single center double-blind randomized controlled phase II pilot trial

Introduction: Hyperosmolar solutions are prescribed in neurosurgery patients to provide satisfactory intraoperative brain relaxation and to lower cerebral injuries related to surgical retractors. Mannitol is traditionally considered as the first-choice solution for brain relaxation in neurosurgery patients. Hypertonic sodium lactate infusion was reported to provide a higher and longer osmotic effect compared to mannitol in severely brain-injured patients and to prevent impaired cerebral energetics related to brain injuries. To date, the clinical effectiveness of hypertonic sodium lactate infusion has never been studied in neurosurgery patients. The hypothesis of the study is that hyperosmolar sodium lactate infusion may provide satisfactory intraoperative brain relaxation in patients undergoing scheduled craniotomy for supratentorial brain tumor resection. Methods and analysis: We designed a phase II randomized, controlled, double-blind, single-center pilot trial, and aim to include 50 adult patients scheduled for craniotomy for supratentorial brain tumor resection under general anesthesia. Patients will be randomized to receive either mannitol (conventional group) or hypertonic sodium lactate (intervention group) infusion at the time of skin incision. Brain relaxation (primary outcome) will be assessed immediately after opening the dura by the neurosurgeon blinded to the treatment allocated using a validated 4-point scale. The primary outcome is the proportion of satisfactory brain relaxation, defined as brain relaxation score of 3 or 4. Ethics and dissemination: This study was approved by the Ethics Committee (Comite de Protection des Personnes Est III) and authorized by the French Health Authority (Agence Nationale de Securite des Medicaments, Saint-Denis, France). The University Hospital of Besancon is the trial sponsor and the holder of all data and publication rights. Results of the study will be submitted for publication in a peer-review international medical journal and for presentation in abstract (oral or poster) in international peer-reviewed congresses. Registration: The trial is registered with (Identifier: NCT04488874, principal investigator: Prof Guillaume Besch, date of registration: July 28, 2020).