Cerebrospinal Fluid Lactate Levels, Brain Lactate Metabolism and Neurologic Outcome in Patients with Out-of-Hospital Cardiac Arrest.

BACKGROUND/OBJECTIVE: Cerebrospinal fluid (CSF) and serum lactate levels were assessed to predict poor neurologic outcome 3 months after return of spontaneous circulation (ROSC). We compared arterio-CSF differences in the lactate (ACDL) levels between two neurologic outcome groups. METHODS: This retrospective observational study involved out-of-hospital cardiac arrest (OHCA) survivors who had undergone target temperature management. CSF and serum samples were obtained immediately (lactate0), and at 24 (lactate24), 48 (lactate48), and 72 (lactate72) h after ROSC, and ACDL was calculated at each time point. The primary outcome was poor 3-month neurologic outcome (cerebral performance categories 3-5). RESULTS: Of 45 patients, 27 (60.0%) showed poor neurologic outcome. At each time point, CSF lactate levels were significantly higher in the poor neurologic outcome group than in the good neurologic outcome group (6.97 vs. 3.37, 4.20 vs. 2.10, 3.50 vs. 2.00, and 2.79 vs. 2.06, respectively; all P < 0.05). CSF lactate's prognostic performance was higher than serum lactate at each time point, and lactate24 showed the highest AUC values (0.89, 95% confidence interval, 0.75-0.97). Over time, ACDL decreased from - 1.30 (- 2.70-0.77) to - 1.70 (- 3.2 to - 0.57) in the poor neurologic outcome group and increased from - 1.22 (- 2.42-0.32) to - 0.64 (- 2.31-0.15) in the good neurologic outcome group. CONCLUSIONS: At each time point, CSF lactate showed better prognostic performance than serum lactate. CSF lactate24 showed the highest prognostic performance for 3-month poor neurologic outcome. Over time, ACDL decreased in the poor neurologic outcome group and increased in the good neurologic outcome group.

Does Combining Biomarkers and Brain Images Provide Improved Prognostic Predictive Performance for Out-Of-Hospital Cardiac Arrest Survivors before Target Temperature Management?

We examined whether combining biomarkers measurements and brain images early after the return of spontaneous circulation improves prognostic performance compared with the use of either biomarkers or brain images for patients with cardiac arrest following target temperature management (TTM). This retrospective observational study involved comatose out-of-hospital cardiac arrest survivors. We analyzed neuron-specific enolase levels in serum (NSE) or cerebrospinal fluid (CSF), grey-to-white matter ratio by brain computed tomography, presence of high signal intensity (HSI) in diffusion-weighted imaging (DWI), and voxel-based apparent diffusion coefficient (ADC). Of the 58 patients, 33 (56.9%) had poor neurologic outcomes. CSF NSE levels showed better prognostic performance (area under the curve (AUC) 0.873, 95% confidence interval (CI) 0.749-0.950) than serum NSE levels (AUC 0.792, 95% CI 0.644-0.888). HSI in DWI showed the best prognostic performance (AUC 0.833, 95% CI 0.711-0.919). Combining CSF NSE levels and HSI in DWI had better prognostic performance (AUC 0.925, 95% CI 0.813-0.981) than each individual method, followed by the combination of serum NSE levels and HSI on DWI and that of CSF NSE levels and the percentage of voxels of ADC (AUC 0.901, 95% CI 0.792-0.965; AUC 0.849, 95% CI 0.717-0.935, respectively). Combining CSF/serum NSE levels and HSI in DWI before TTM improved the prognostic performance compared to either each individual method or other combinations.

Usefulness of Intracranial Pressure and Mean Arterial Pressure for Predicting Neurological Prognosis in Cardiac Arrest Survivors Who Undergo Target Temperature Management.

We aimed to compare the relationship of mean arterial pressure (MAP) and intracranial pressure (ICP) to predict the neurological prognosis in cardiac arrest (CA) survivors. We retrospectively examined out-of-hospital CA patients treated with targeted temperature management. ICP was measured using cerebrospinal fluid (CSF) pressure, whereas MAP was measured as blood pressure monitored through the radial or femoral artery during CSF pressure measurement. Primary outcome was 6-month neurological outcome. Of 92 enrolled patients, the favorable outcome group comprised 31 (34%) patients. The median and interquartile range of MAP were significantly higher and ICP was significantly lower in patients with favorable neurological outcomes than in those with unfavorable neurological outcomes (94.3 mmHg [80.0-105.3] vs. 82.0 mmHg [65.3-96.3], p = 0.021 and 9.4 mmHg [10.8-8.7] vs. 18.8 mmHg [20.0-15.7], p < 0.001, respectively). ICP showed the higher area under the receiver operating characteristic curve (area under curve [AUC] = 0.953, 95% confidence interval [CI] = 0.888-0.986) for neurological outcome prediction. MAP showed the lower AUC (0.648, 95% CI = 0.541-0.744). Higher accurate prognosis was predicted by ICP than MAP, and the prognostic performance was good. Prospective multicenter studies are required to confirm these results.

Reversible Acute Blindness in Suspected Metformin-Associated Lactic Acidosis.

BACKGROUND: Metformin is commonly used for the treatment of type 2 diabetes mellitus. Renal insufficiency is one of the contraindications for its use. Inadvertent prescription in patients with renal insufficiency may lead to metformin-associated lactic acidosis (MALA), which is associated with a high risk of mortality. Consequently, the early recognition and management of MALA is essential. CASE REPORT: We present the case of a 68-year-old man who had reversible blindness resulting from severe lactic acidosis. On presentation, he was alert, oriented, and had no complaints except mild abdominal discomfort and blindness. He denied any history of trauma or drug abuse. The results of the laboratory studies showed severe metabolic acidosis with a high anion gap and increased levels of serum creatinine. There were no predisposing ocular or neurologic lesions that could have induced the blindness. Although the blood levels of methanol, ethanol, and metformin were not estimated, correction of acidosis and hemodialysis led to a complete recovery. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Rarely, transient blindness may occur in patients with fatal severe metabolic acidosis. Evaluation for the presence of metabolic acidosis and a detailed medical history are essential in the management of acute blindness in such patients.