Lactate Therapy After Traumatic Brain Injury

Study: Prospective, single-centre phase II interventional study. The study will take place at the Department of Intensive Care Medicine, Lausanne University Medical Center (Centre Hospitalier Universitaire Vaudois, CHUV), Lausanne, Switzerland. Patient population: Patients will be monitored with an intra-parenchymal monitoring system, consisting of ICP (Codman®, Integra Neurosciences), PbtO2 (Licox®, Integra Neurosciences) and cerebral microdialysis (CMA Microdialysis®) catheters, based on the protocol for management of TBI presently in use at our center. Each patient will receive a continuous infusion of sodium lactate (composition: lactate 1'000 mmol/L, Na 1'000 mmol/L: concentration 20-40 µmol/kg/min) for 3-6 hours. Sodium lactate will be prepared locally by the Pharmacie Centrale, CHUV, Lausanne. Each patient will serve as his/her internal control, and the effect of sodium lactate on all brain physiological variables measured will be anayzed before, during and at the end of sodium lactate infusion. The main parameters of efficacy are increases of MD glucose, MD pyruvate, PbtO2, and CBF, during sodium lactate perfusion. For both MD glucose and MD pyruvate, we fixed as the minimal detectable effect of sodium lactate infusion a 30% increase of glucose and pyruvate at the end of the study. To obtain a power of 0.8 with an alpha of 0.05, the number of patients required to complete the study is 33. We therefore plan to include 35 patients. Statistical analysis: At each time-point (baseline, during perfusion, end of sodium lactate infusion), differences of mean MD glucose, lactate, pyruvate, PbtO2, CBF, Mean transit time, ICP, CPP will be analyzed. We will also examine the percentage time spent with abnormal values (MD glucose \< 1 mmol/L, PbtO2 \< 20 mm Hg, ICP \> 20 mm Hg). Differences will be compared using ANOVA for repeated measures.