Lactate Is a Strong Predictor of Poor Outcomes in Patients with Severe Traumatic Brain Injury

Background: Lactate is a metabolic byproduct. It has traditionally been seen as a byproduct of oxygen-deprived glycolysis and ischemia. Therefore, our main goal is to examine the influence of lactate levels (LLs) on clinical outcomes in patients with severe Traumatic brain injury (TBI). Method: This is a level 1 single-center, retrospective study of patients with severe TBI between January 1, 2020- December 31, 2023, inclusive. Only patients with an Abbreviated Injury Scale (AIS), value of 3 or higher were included. Results: Single-factor ANOVA indicated a significant increase in LLs with decreasing age (Hospital admission: p = 1.53E-13, ICU admission: p = 0.0183, Hospital discharge: p = 0.02, Death: p = 0.0149). Linear regression models showed a significant decrease in age compared to Hospital admission LLs (p = 2.65E-09), Intensive Care Unit (ICU) admission LLs (p = 0.01), and Death LLs (p = 0.00295). Prognostic scores such as Injury Severity Scores (ISS) and Glasgow Coma Score (GCS) showed a strong correlation with both Hospital admission and ICU admission LLs. ANOVA indicated higher LLs with increasing ISS (Hospital admission: p = 5.22E-06, ICU admission: p = 1.92E-05) and increasing LLs with decreasing GCS (Admission: p = 3.42E-08, ICU admission: p = 1.74E-09). Linear regressions revealed a strong positive correlation between ISS and LLs (Hospital admission: p = 3.69E-07, ICU admission: p = 2.90E-06). On linear regression, the lactate level measured at hospital admission and ICU admission strongly positively associated with the length of stay (LOS) in the hospital (Hospital admission: p = 0.00342, ICU admission: p = 0.0163), LOS in the ICU (Hospital admission: p = 0.0141, ICU admission: p = 0.0234), ventilator days (Hospital admission: p = 0.002513, ICU admission: p = 8.23E-05), and mortality (Hospital admission: p = 8.13E-05, ICU admission: p = 3.93E-05). Discussion: We discovered that high LLs were linked to longer stays in the hospital and ICU, as well as more days requiring a ventilator, and higher mortality rates in patients with severe TBI. Enhanced LLs had the most notable impact on the number of days on a ventilator and mortality, followed by longer hospital and ICU stays. Therefore, lactate can be considered a strong predictor of poor clinical outcomes in patients with severe TBI.