Clinical effectiveness of intravenous hypertonic sodium lactate infusion for intra-operative brain relaxation in supratentorial brain tumour surgery

BACKGROUND: Adequate brain relaxation is a key aspect of anaesthetic management in brain surgery. OBJECTIVE: The aim of this study was to assess the clinical effectiveness of intravenous hypertonic sodium lactate (HSL) for intra-operative brain relaxation in supratentorial brain tumour surgery. DESIGN: Double-blind, phase II randomised pilot trial. SETTING: Tertiary care centre for neurosurgery. PATIENTS: Adult patients admitted for planned supratentorial brain tumour surgery. MAIN OUTCOME MEASURES: The primary outcome was the proportion of patients presenting satisfactory brain relaxation, assessed by the surgeon after opening the dura using a validated 4-point scale. Secondary outcomes were blood lactate level at T 0 +30 min, T 0 +60 min and T 0 +180 min, and the rate of adverse events. Patients received either HSL 2.5 ml kg -1 (interventional group) or 20% mannitol 5 ml kg -1 (conventional group) infusion started at skin incision (T 0 ). RESULTS: Twenty-four and 22 patients were analysed in the interventional and conventional groups, respectively [age: 60 ± 12 vs. 57 ± 12 years; females: 7 (29%) vs. 11 (50%); ASA physical status >II: 2 (8%) vs. 4 (18%)]. The primary outcome was observed in 23 {96% [95% confidence interval (CI), 77 to 100]} patients in the interventional group and in 20 [91% (95% CI, 69 to 98)] patients in the conventional group ( P = 0.60). Median [IQR] lactate levels peaked at T 0 +30 min, 8.20 [6.98 to 8.73] mmol l -1 , in the interventional group and were higher than in the conventional group at each time point. Six and one patients experienced hypokalaemia in the interventional and conventional groups, respectively. No adverse events related to HSL infusion were observed. CONCLUSION: Pilot data suggests that HSL could provide efficient brain relaxation in patients undergoing supratentorial brain tumour resection via craniotomy, but further adequately powered studies are needed to confirm its comparative efficacy with mannitol. TRIAL REGISTRATION: ClinicalTrials.gov NCT04488874.