Succinylcholine is a myorelaxant agent often used during rapid sequence induction for patients who need to undergo general anesthesia but who are at risk of pulmonary aspiration of gastric content. Whereas other myorelaxant agents are monitored with train of four stimulation to assess onset and duration, few anesthesiologists use train of four stimulation for onset of succinylcholine, as the anesthesiologists evaluate the effect with the time from injection (usually one minute) and the muscle fasciculation due to the release of acetylcholine.

The data available on onset duration of this drug are old and bases on only few studies, but the succinylcholine if sometime harmful (anaphylaxis , cardiac arrest, bronchospasm).

The investigators want to assess the onset time of succinylcholine with an objective toll , the train of four stimulation, and evaluate if the clinical judgment of the anesthesiologist is reliable to predict an adequate moment for endotracheal intubation.

Inclusion Criteria:

• Every patient undergoing general anesthesia with the use of suxamethonium for induction as assessed by the anesthesiologist

Exclusion Criteria:

• Patient under 18 years old
• Pregnant woman
• Nasotracheal intubation
• Monitoring of train of four at the adductor pollis impossible (such as patient with no arm )

Every patients undergoing general anesthesia with the use of suxamethonium for induction as assessed by the anesthesiologist