Cerebral lactate uptake following half-molar sodium lactate therapy in traumatic brain injury : a brief report.

Exogenous sodium lactate has many advantages following traumatic brain injury, including intracranial pressure control and alternative energetic supply. However, it remains unclear whether half-molar sodium lactate (HSL) is effectively incorporated in brain metabolism, which we can verify using the arteriovenous difference in lactate (AVDlac). Hence we compared the AVDlac in patients with severe traumatic brain injury receiving equiosmolar bolus of sodium lactate or mannitol for intracranial hypertension (IH) treatment. We included 23 patients : 14 received HSL for 25 IH episodes, and 9 received mannitol for 19 episodes (total of 44 IH episodes). We observed that the median variation in AVDlac was positive in the group that received HSL (∆ +0.1 [IQR -0.08-0.2] mmol/L), which suggests a net lactate uptake by the brain. On the other hand, it was negative in the group that received mannitol (∆ -0.0 [IQR -0.1 to 0.0] mmol/L), indicating a net lactate export. Finally, there were more positive AVDlac values in the group that received HSL, and more negative AVDlac values in the group that received mannitol (Fisher's exact p = 0.04). Our study reports the first evidence of a positive AVDlac, which corresponds to a net lactate uptake by the brain, in patients that received HSL for severe TBI. Our results constitute a bedside confirmation of the integration of lactate into the brain metabolism and pave the way for a wider dissemination of sodium lactate in the daily clinical care of patients with traumatic brain injury.