The goal of the CELESTE study is to evaluate whether calibration of EMG is needed for reliable interpretation of neuromuscular function and if so, to identify the minimal necessary depth of anesthesia.

Neuromuscular monitoring is used to document neuromuscular function intra-operatively. Failure to restore neuromuscular function prior to extubation results in residual neuromuscular blockade which is associated with increased postoperative morbidity and mortality. It is essential to document baseline neuromuscular function before administration of the neuromuscular blocking agent. However, during anesthesia induction, neuromuscular monitoring is rarely calibrated due to its time-consuming nature coinciding with the patients' loss of consciousness.

The CELESTE trial is a randomized, prospective, observational proof-of-concept study. We plan to enroll sixty adult participants scheduled for elective non-cardiac surgery requiring general anesthesia with moderate neuromuscular blockade. Participants will be randomized into three electromyography (EMG) calibration groups: based on state entropy ("depth of anesthesia"), group 1 will receive "analgesic calibration", group 2 "sedated calibration", and group 3 "no calibration". Participants will be randomly allocated to receive calibration at a certain depth of anesthesia. All participants will receive a standard EMG performed on the contralateral arm. Standard EMG will be calibrated at state entropy of 50.

Inclusion Criteria:

• signed informed written consent
• BMI 17.5-30 kg/m^2
• ASA <= 3
• supine positioning during surgery with intraoperative access to both arms
• absence of allergy to muscle relaxants and reversal agents
• absence of neuromuscular disease

Exclusion Criteria:

• ambulatory patients for whom discharge is planned within 12 hours of anaesthesia
• patients undergoing minor surgical
• procedures scheduled outside the operating room
• patients who are endotracheally intubated prior to surgery
• pregnancy
• indication for rapid sequence induction
• patients undergoing arm surgery
• patients with preceding injuries impairing muscle or nerve function of the arm (e.g., finger amputation)

The CELESTE study will be performed in adult patients scheduled for elective non-cardiac surgery requiring general anesthesia and moderate neuromuscular blockade.