The antagonism of neuromuscular blocking agents (NMBA) (or curares), as well as the antagonism of other drugs used in anesthesia, is a major challenge for the speciality.

Residual paralysis is indeed a risk factor for post-operative morbidity and mortality and antagonization of curares at the end of the procedure is associated with a reduction in mortality .

Its use should be as large as possible and its contraindications are extremely rare.

The antagonism of the NMBA reduces the duration of the neuromuscular block and the complications that are associated .

In this study, the investigators use mivacurium (or Mivacron) as non-depolarizing curare and neostigmine as an antagonist.

Neostigmine reduces the duration of the neuromuscular block induced by mivacurium, By reducing the breakdown of acetylcholine, neostigmine induces an increase in acetylcholine in the synaptic cleft which competes for the same binding site as nondepolarizing neuromuscular blocking agents, and reverses the neuromuscular blockade.

But the use of neostigmine in current practice is not very widespread in this clinical situation.

The reduction in the duration of the block is significant in comparison with a spontaneous recovery .

Moreover, spontaneous recovery is not always complete and sometimes very long.

Nevertheless, its action is effective and this study could support this use but also specify the duration and the quality of the return to normal of the neuromuscular transmission.

Inclusion Criteria:

• Patients American Society of Anesthesiologists (ASA) 1 to 3
• Absence of neuromuscular disease, renal and hepatic insufficiency
• Absence of medication that could interfere with the mediators of the neuromuscular junction

Exclusion Criteria:

• Bronchial asthma
• Parkinson disease
• BMI> 35
• Known hypersensitivity to neostigmine or to any of the excipients of Neostigmine