Neuromuscular monitoring is used to evaluate neuromuscular function intraoperatively and to ensure complete neuromuscular recovery at the end of anaesthesia. Therefore, the lack of reliable neuromuscular monitoring devices that are not cumbersome to use is a major shortcoming for anaesthesia. A recently developed mechanomyography (MMG) device may meet these partially unmet needs due to its measurement of the patient's contractile force instead of its surrogates (i.e., acceleration, velocity), including the response to physiologically relevant tetanic stimulation. However, it is unclear whether the reliability of the newly developed MMG device is similar to or better than the currently available gold standard of neuromuscular monitoring based on electromyography (EMG).

The MEMORY trial is a randomized clinical agreement study which will prospectively enrol thirty ASA 1 or 2 patients ≥ 18 years scheduled for non-cardiac surgery requiring general anaesthesia and neuromuscular blockade for optimisation of surgical conditions. The patient's neuromuscular function is measured on one hand with MMG and the other hand with EMG in a randomised fashion. Additionally, randomisation will be stratified the domination of one hand.

In the MEMORY trial we will test the hypothesis, that a newly developed MMG sensor provides not less reliable measurements of neuromuscular function compared to EMG in adult patients. Reliability includes agreement, precision, and the absence of staircase phenomenon and idiosyncratic responses to train-of-four (TOF) stimulation. In addition, we will explore if measurement of tetanic fade will provide more precise information about complete neuromuscular recovery than the current standard of TOF ratio >0.9.

Inclusion Criteria:

• age ≥ 18 years
• ASA < 3
• scheduled for non-cardiac surgery requiring general anaesthesia and neuromuscular blockade for optimisation of surgical conditions
• positioning during surgery with intraoperative access to both arms

Exclusion Criteria:

• allergy to muscle relaxants and reversal agents
• neuromuscular disease
• procedure is scheduled outside the operating room
• need of endotracheal intubation prior to surgery
• need of rapid sequence induction
• pregnancy, breastfeeding or 30 days postpartum
• surgical procedure or examination findings which are a contraindication for a supraglottic airway device
• employee of the investigator or study site directly involved in this study or other studies under the direction of the investigator or study site
• family member of the investigator
• custodial accommodation
• alcohol or drug abuse
• patients with preceding injuries impairing muscle or nerve function of the arm
• Participation in other studies with investigational drugs or devices within 4 weeks prior to screening or missing agreement not to participate in any other study at the same time or within a period of one month after the MEMORY study

The MEMORY trial is a randomized clinical agreement study which will prospectively enrol adult ASA 1 or 2 patients scheduled for non-cardiac surgery requiring general anaesthesia and neuromuscular blockade for optimisation of surgical conditions.