In this study, the antagonism of neostigmine, a cholinesterase inhibitor, on continuous infusion of mivacurium during foot and ankle surgery under general anesthesia was investigated, and the appropriate time point of antagonism was explored.

Mivacurium is currently the shortest-acting benzylisoquinoline nondepolarizing muscular relaxant in clinical practice, which is suitable for short surgery. Its continuous infusion can also be used in medium-term surgery with uncertain operation time, which can accelerate the recovery of postoperative muscle relaxation. Whether continuous infusion of mivacurium requires antagonism and the appropriate time point of antagonism is controversial.

Inclusion Criteria:

• 18 - 65 years old;
• American Society of Anesthesiologists (ASA) physical stastus classification system: I-II;
• Body mass index (BMI) 18.5 - 30 kg/m2
• Patients with normal cholinesterase levels before the operation

Exclusion Criteria:

• Refusal to participate in the study;
• ASA classification of grade III or above;
• Severe organ dysfunction, difficult airway or neurological muscle disorders;
• Taking drugs that affect neuromuscular monitoring or neuromuscular conduction function;
• Allergic to the test drug or having other contraindications;
• Pregnant and lactating women