Metabolic alkalosis: a new red flag in status epilepticus

Status epilepticus (SE) is a heterogeneous neurological emergency with significant variability in prognosis, influenced by underlying disease and pathophysiological context. Acid-base disturbances are common in critically ill patients, yet their distribution and impact in SE patients remain poorly understood.

This was an observational cohort study including non-hypoxic SE patients with available blood gas analysis within the first 24 h of SE, treated at the University Hospital of Geneva, Switzerland between 2015 and 2023. Acid-base disturbances were classified using the Henderson-Hasselbalch equation, with prevalent metabolic alkalosis confirmed through the Stewart approach. Primary outcomes were in-hospital mortality, Glasgow Outcome Scale (GOS) at discharge, and return to premorbid neurologic function.

Among 540 SE patients, 365 were included. Half of patients exhibited acid-base disturbances within the initial 24 h of SE, with metabolic and respiratory acidosis being the most prevalent, though not prognostically significant. After correction for possible confounders, metabolic alkalosis (6%) was associated with increased in-hospital mortality (P = 0.011; OR = 4.87, 95% CI = 1.29-7.84), worse GOS (P = 0.012; OR = 3.18, 95% CI = 1.29-7.84), and reduced likelihood of returning to premorbid function (P = 0.017; OR = 3.30, CI95% = 1.24-8.80). Following the Stewart approach, 9% of patients had predominant metabolic alkalosis, associated with worse GOS (P = 0.005; OR:3.37, 95%CI = 1.45-7.82), and reduced chance of returning to baseline (P = 0.012; OR = 3.29, CI95% = 1.30-8.32). Metabolic alkalosis was related to hypoalbuminemia and lower serum potassium.

Metabolic alkalosis strongly predicts mortality and adverse functional outcome in SE patients. Prospective studies should assess whether early detection and correction of metabolic alkalosis and related electrolyte imbalances can improve SE prognosis.