Accidental Sugammadex Administration Before Rocuronium During Electroconvulsive Therapy: The Zero-Complexation Scenario.

Electroconvulsive therapy (ECT) performed with rocuronium-sugammadex requires both agents to be prepared before each session, creating a persistent syringe-swap risk that compounds with repetition. A 48-year-old woman scheduled for her sixth ECT session received sugammadex 200 mg instead of rocuronium due to syringe misidentification driven by task automaticity accumulated over 5 uneventful preceding sessions. Because the entire sugammadex dose remained unbound in plasma (a state we term "zero-complexation"), subsequently administered rocuronium 100 mg (1.41 mg/kg) failed to achieve adequate neuromuscular blockade. This scenario is pharmacokinetically distinct from the well-described post-reversal re-dosing situation: 200 mg of free sugammadex sequesters ~56 mg of rocuronium, leaving an insufficient effective dose regardless of the total amount administered. The session was postponed and completed the following day uneventfully with standard-dose rocuronium. We present a management algorithm and a safety checklist designed for the repeated-session context of ECT. This case demonstrates that anesthetic teams using rocuronium-sugammadex for ECT must recognize the cumulative automaticity risk inherent in serial sessions and implement structural safeguards accordingly.