This is an epidemiological multicenter, observational, prospective study, designed to determine the incidence of postoperative residual neuromuscular blockade - defined by a TOF (train-of-four) ratio < 0.9 - at PACU arrival.

Subjects aged at least 18 years old (n=360) admitted for different types of elective surgical procedures requiring general anesthesia with neuromuscular blocking agents will be included.

This is a multicenter, observational/non-interventional study involving adult patients undergoing different types of elective surgical procedures requiring general anesthesia with neuromuscular blocking agents.

The study will have two periods:

• Period 1 - Evaluation at PACU arrival.
• Period 2 - Collection of hospital patient discharge data.

A total of 360 patients will be included from approximately 10 centers in Portugal, where the PACU is adjacent to the Operating Room (OR). Each center should recruit between 30 and 40 patients.

Each subject is considered to be enrolled in the study when the subject has provided written informed consent.

Enrollment will be stopped when approximately 360 patients are recruited.

A subject is considered to have completed the trial after all of the protocol specified activities are completed. A subject is considered to have discontinued after he/she has withdrawn consent or has been discontinued.

Overall, study start is when the first site is initiated and study ends at database lock.

During the routine preoperative anesthesia visit the patient will be asked to participate in the study. A description of the study will be provided to the patient by the investigator or qualified designee and any questions will be properly answered. If the patient agrees to participate in the study an informed consent form (ICF) will be signed.

Consent must be documented by the subject's dated signature or by the subject's legally acceptable representative's dated signature on a consent form along with the dated signature of the person conducting the consent discussion. A copy of the signed and dated consent form should be given to the subject before participation in the study.

The initial informed consent form, any subsequent revised written informed consent form and any written information provided to the subject must receive the IRB/ERC's (Institutional Review Board) ) approval/favorable opinion in advance of use. The subject or his/her legally acceptable representative should be informed in a timely manner if new information becomes available that may be relevant to the subject's willingness to continue participation in the study.

All consented subjects will be given a unique patient number that will be used to identify the subject for all procedures. Each subject will be assigned only one patient number.

Immediately after patient arrival in the PACU and as soon as clinically adequate (basic monitoring and oxygen therapy in place) the anesthesiologist assigned to the PACU (who was not involved in the anesthetic procedure) will collect demographic data (gender, age, weight, height), vital signs (heart rate, blood pressure, oxygen saturation and temperature). Neuromuscular blockade (TOF Ratio) will be measured. Clinical history, co-morbidities, surgical diagnosis, ASA (American Society of Anesthesiology) classification and perioperative medication data (dosage and last administration time) will be collected as well.

As this is an observational study, intra-operative monitoring of neuromuscular blockade will not be mandatory by protocol and will be left at the discretion of the anesthesiologist as according to the clinical practice. Only information about whether this evaluation was performed or not, and if yes if it was used quantitative or qualitative methods, will be collected in the CRF (case report form) .

Neuromuscular blockade evaluation Neuromuscular blockade will be evaluated using a quantitative method. Three consecutive TOF stimulations will be applied. In case these 3 measures differ more than 20%, another sequence of 3 consecutive TOF measurements will be considered. If after the 2nd sequence the 3 consecutive TOF measurements still differ more than 20% between the maximum and the minimum the patient will be excluded.

This study will reflect real life clinical practice. The anesthetic technique in terms of drugs and type of monitoring used will be of entire responsibility of the anesthesiologist.

All study activities will be consistent with EU (European Union) directive 2001/20/EC section for non- interventional studies :

• NMBAs (neuromuscular blocking agents) and reversal agents (as well as all drugs which will be used during the anesthesia) administration will be done in accordance with routine anesthesiology practice and labeling of these medicine products;
• No further interventional means, methods or procedures, are scheduled for subjects, which would otherwise not be applied;
• Furthermore, there will be no additional visits to the hospital or a mandatory visit schedule, deviating from daily clinical practice.

Inclusion Criteria:

• 18 years of age or older;
• Informed consent signed;
• Admission for elective surgery;
• Administration of non-depolarizing NMBAs during surgery

Exclusion Criteria:

• Admission for emergency surgery;
• Reoperation on the same hospital admission;
• More than 10 minutes elapsed between extubation and neuromuscular block monitoring at PACU

Patients scheduled for surgery on 10 centers that accepted to participate in the study.