Comparison of Acceleromyography and Electromyography in Obese Patients Undergoing General Anesthesia (OBAEG)

Comparison of Acceleromyography and Electromyography in Obese Patients Undergoing General Anesthesia With Rocuronium: A Prospective Observational Study

The goal of this prospective observational study is to compare two different methods of monitoring muscle relaxation during anesthesia - acceleromyography (AMG) and electromyography (EMG) - in people with obesity who are having bariatric surgery with general anesthesia and the muscle relaxant rocuronium.

The main question is: Which method is more accurate and precise in measuring the Train-of-Four (TOF) ratio during surgery? As part of this comparison, researchers will also note how quickly each method detects recovery of muscle function after the reversal drug sugammadex.

Participants will:

• Receive standard anesthesia care for bariatric surgery, including rocuronium to relax the muscles.
• Have two small monitoring devices applied, one to each hand: AMG on one hand, EMG on the other.
• Be monitored for muscle function during surgery and after receiving sugammadex to reverse the muscle relaxation.

Researchers will also record how easy each device is to use and whether participants have any breathing problems after surgery.

Study Overview

• Status: Not yet recruiting
• Conditions: Obesity
• Intervention / Treatment: Procedure: Neuromuscular monitoring with electromyography (EMG); Procedure: Neuromuscular monitoring with acceleromyography (AMG)

• Study Type: Observational
• Enrollment (Estimated): 30

Contacts and Locations

• Study Contact: Name: Michele Carron, MD, PhD; Phone Number: +390498213090; Email: michele.carron@unipd.it

Study Locations

• Italy
  • PD
    • Padua, PD, Italy, 35127
      • Azienda Ospedale - Università di Padova (Padua University Hospital)
      • Contact: Michele Carron; Phone Number: +390498213090; Email: michele.carron@unipd.it

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Adults aged 18-65 years with pathological obesity (Class II with comorbidities or Class III) scheduled for bariatric surgery under general anesthesia.

Description

Inclusion Criteria:

• Adults aged 18-65 years
• Pathological obesity (Class II with comorbidities or Class III)
• Scheduled for bariatric surgery under general anesthesia
• Written informed consent obtained

Exclusion Criteria:

• Severe acute or chronic respiratory disease (e.g., asthma, COPD, severe restrictive disease)
• Severe acute or recent cardiac disease (e.g., acute or recent myocardial infarction, inducible ischemia, heart failure)
• End-stage hepatic or renal disease
• Intolerance, allergy, or contraindication to study-related drugs
• Absence of informed consent

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Patients with obesity undergoing bariatric surgery; Adults with obesity scheduled for bariatric surgery under general anesthesia. Each participant will be monitored for neuromuscular function using both acceleromyography (AMG) and electromyography (EMG) during surgery and after administration of sugammadex.

Procedure: Neuromuscular monitoring with electromyography (EMG); Neuromuscular function will be assessed using an electromyography device applied to the hand. The device measures the electrical activity of muscles in response to ulnar nerve stimulation to calculate the Train-of-Four (TOF) ratio.; Procedure: Neuromuscular monitoring with acceleromyography (AMG); Neuromuscular function will be assessed using an acceleromyography device applied to the hand. The device measures the acceleration of thumb movement in response to ulnar nerve stimulation to calculate the Train-of-Four (TOF) ratio.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean paired difference in TOF ratio (AMG vs EMG)	Mean difference between acceleromyography (AMG) and electromyography (EMG) measurements of the Train-of-Four (TOF) ratio (unitless) obtained from paired intraoperative recordings.	Intraoperative period

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time to optimal conditions for tracheal intubation	Time from rocuronium administration to achievement of optimal intubation conditions, defined as TOF count = 0 or deep block confirmed by post-tetanic count (PTC). Measured with both AMG and EMG.	From rocuronium administration to tracheal intubation (approximately 1-3 minutes).
Maintenance of deep neuromuscular block	Duration and stability of deep block (PTC < 5) maintained during anesthesia, as measured by AMG and EMG.	From induction of anesthesia to start of reversal with sugammadex (approximately 60-120 minutes)
Time to recovery of TOF ratio ≥ 0.9 after sugammadex	Time from administration of sugammadex to achievement of TOF ratio ≥ 0.9 with each monitoring method (AMG and EMG).	From administration of sugammadex to achievement of TOF ratio ≥ 0.9 (typically 1-5 minutes).
Usability and quality assessment of AMG and EMG monitoring	Overall usability rating using a five-point Likert scale (1 = extremely poor, 5 = optimal) for AMG and EMG monitoring devices.	At the end of anesthesia (single assessment).
Incidence of postoperative respiratory complications	Number of participants experiencing respiratory complications (e.g., hypoxemia, airway obstruction, reintubation, or need for assisted ventilation) in the post-anesthesia care unit (PACU).	Through PACU discharge (approximately 1-2 hours after surgery).
Perioperative changes in heart rate	Heart rate (beats per minute, bpm) measured at predefined intraoperative and postoperative time points.	From induction of anesthesia through PACU discharge.
Perioperative changes in mean arterial pressure	Mean arterial pressure (mmHg) measured at predefined intraoperative and postoperative time points	From induction of anesthesia through PACU discharge
Perioperative changes in oxygen saturation (SpO₂)	Oxygen saturation (SpO2), %) measured at predefined intraoperative and postoperative time points.	From induction of anesthesia through PACU discharge
Perioperative changes in perfusion index	Perfusion index (Unitless) measured at predefined intraoperative and postoperative time points.	From induction of anesthesia through PACU discharge.

Collaborators and Investigators

• Sponsor: University of Padova
• Collaborators: University Hospital, Padua, Italy

Publications and helpful links

General Publications

• Naguib M, Brull SJ, Johnson KB. Conceptual and technical insights into the basis of neuromuscular monitoring. Anaesthesia. 2017 Jan;72 Suppl 1:16-37. doi: 10.1111/anae.13738.
• Fuchs-Buder T, Romero CS, Lewald H, Lamperti M, Afshari A, Hristovska AM, Schmartz D, Hinkelbein J, Longrois D, Popp M, de Boer HD, Sorbello M, Jankovic R, Kranke P. Peri-operative management of neuromuscular blockade: A guideline from the European Society of Anaesthesiology and Intensive Care. Eur J Anaesthesiol. 2023 Feb 1;40(2):82-94. doi: 10.1097/EJA.0000000000001769. Epub 2022 Nov 15.
• Carron M, Safaee Fakhr B, Ieppariello G, Foletto M. Perioperative care of the obese patient. Br J Surg. 2020 Jan;107(2):e39-e55. doi: 10.1002/bjs.11447.
• Wedemeyer Z, Michaelsen KE, Jelacic S, Silliman W, Lopez A, Togashi K, Bowdle A. Accuracy and Precision of Three Acceleromyographs, Three Electromyographs, and a Mechanomyograph Measuring the Train-of-four Ratio in the Absence of Neuromuscular Blocking Drugs. Anesthesiology. 2024 Aug 1;141(2):262-271. doi: 10.1097/ALN.0000000000005051.

Study record dates

Study Major Dates

• Study Start (Estimated): February 1, 2026
• Primary Completion (Estimated): July 30, 2026
• Study Completion (Estimated): September 30, 2026

Study Registration Dates

• First Submitted: November 25, 2025
• First Submitted That Met QC Criteria: December 10, 2025
• First Posted (Actual): December 15, 2025

Study Record Updates

• Last Update Posted (Actual): December 15, 2025
• Last Update Submitted That Met QC Criteria: December 10, 2025
• Last Verified: August 1, 2025

More Information

Terms related to this study

• Keywords: Electromyography; Bariatric Surgery; General Anesthesia; Neuromuscular Blockade; Acceleromyography; Neuromuscular Monitoring
• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Overweight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity
• Other Study ID Numbers: AOP3692_CET; 6296/EST/25 (Other Identifier: Territorial Ethics Committee - Central-East Veneto Area)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared. Aggregate, de-identified study results will be disseminated through peer-reviewed publications and conference presentations

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No