Can succinylcholine be used safely in hyperkalemic patients?

The use of succinylcholine in hyperkalemic patients (serum potassium >5.5 mEq/L) is often viewed as relatively contraindicated, although there are no systematic data to define what preoperative potassium level is safe. We retrospectively reviewed more than 40,000 general anesthetics administered over 70 mo in which succinylcholine was given at the induction. This search yielded 38 patients with a preoperative potassium of 5.6 mEq/L or greater. Survival of the anesthetic was 100%, and no dysrhythmias or other major morbidity were documented upon manual review of the intraoperative automated record keeper charts or the patient medical records. These data allow a 95% confidence interval assessment of maximal risk for an event of 7.9%, which is not negligible, but which almost certainly grossly over-estimates the risk for patients with moderately increased potassium levels. A prospective trial to definitively assess the safety margin for succinylcholine use in hyperkalemic patients would be difficult. Therefore, these data, taken in the context of a compelling case for rapid intubating conditions without long-term paralysis, suggest safety in succinylcholine use in patients with modest hyperkalemia.