Overview
The use of neuromuscular blocking (NMB) agents in modern anesthesia is essential for optimizing surgical exposure and ensuring patient safety. Inadequate neuromuscular recovery at the end of surgery, known as residual curarization, poses significant risks for critical postoperative respiratory complications, aspiration pneumonia, and prolonged recovery times. Therefore, objective neuromuscular monitoring is strongly recommended by international guidelines, including the American Society of Anesthesiologists (ASA) and the European Society of Anaesthesiology and Intensive Care (ESAIC).
In gynecologic oncology surgery, laparoscopic and robotic approaches often require deep neuromuscular blockade (Post-Tetany Count 1-2) to improve abdominal exposure and allow surgeons to work at lower intraperitoneal pressures. However, the extreme Trendelenburg position and the "tucked-in" positioning of the arms under surgical drapes limit the feasibility of traditional acceleromyography (AMG) monitoring methods. Since AMG devices require free movement of the thumb (m. adductor pollicis), they can yield false-positive or unreliable results when the arms are inaccessible, forcing clinicians to rely on subjective monitoring.
The NMTCuff technology, used by the Vision Duo monitor, measures the neuromuscular response via the contraction pressure of the upper arm muscles (m. triceps/biceps brachii) rather than the wrist. Literature indicates that the response of upper arm muscles correlates better with the diaphragm and laryngeal muscles regarding NMB sensitivity compared to the wrist. This feature suggests that the Vision Duo might detect the recovery of respiratory functions earlier and more reliably.
This study aims to evaluate the correlation and time differences in Train-of-Four (TOF) ratios between the NMTCuff and standard AMG methods during gynecologic oncology surgery. Additionally, it will assess the ease of setup and signal continuity of both devices when the patient's arms remain covered under surgical drapes.
This study is purely prospective and observational in terms of clinical management. The neuromuscular monitoring methods used will not interfere with routine anesthesia care, drug dosing, muscle relaxant reversal strategies, or extubation decisions. The clinician performing the anesthesia management will follow the institutional routine protocol, and data from both devices will only be recorded simultaneously and matched for statistical comparison.
Description
Following approval from the institutional non-interventional clinical research ethics committee and obtaining written and verbal informed consent from all participating patients, this prospective study will be conducted on patients scheduled for elective laparoscopic gynecologic oncology surgery. Patients aged 18-75 years with an American Society of Anesthesiologists (ASA) physical status of I-III will be included. Exclusion criteria consist of a known history of neuromuscular disease, severe hepatic or renal insufficiency, a Body Mass Index (BMI) greater than 35 kg/m2, and patient refusal to participate.
Upon arrival in the operating room, standard monitoring will be applied to all patients, including electrocardiography (ECG), peripheral oxygen saturation (SpO2), and non-invasive blood pressure (NIBP). Anesthesia induction will follow a standardized routine institutional protocol: propofol 2-3 mg/kg, remifentanil 0.5-1 mcg/kg, and rocuronium 0.6 mg/kg to facilitate endotracheal intubation and induce neuromuscular blockade.
Simultaneously, two different neuromuscular monitoring methods will be applied to each patient as follows:
Group 1 - NMTCuff (Vision Duo): Measurements will be performed using a specialized NMT cuff belonging to the Vision Duo monitor. This cuff is placed around the patient's non-dominant upper arm, and neuromuscular transmission is assessed via pressure-sensitive sensors during muscle contraction.
Group 2 - AMG (Standard TOF): Measurements will be performed using a standard acceleromyography (AMG) Train-of-Four (TOF) sensor attached to the contralateral wrist along the ulnar nerve pathway.
At the end of the surgical procedure, routine reversal of the neuromuscular blockade will be performed using Sugammadex at a dose of 2 mg/kg. The recovery times-specifically the duration from the exact moment of Sugammadex administration until the TOF ratio reaches 90% and 100% (matching the Vision Duo Auto-Pilot specification)-will be recorded separately for both devices using a digital stopwatch. Clinical assessment parameters at the time of extubation, including tidal volume and the 5-second head lift test, will also be documented.
This study is purely prospective and observational regarding clinical anesthesia management. The alternative monitoring methods will not intervene in or alter the routine anesthesia care, muscle relaxant dosages, reversal strategies, or extubation decisions. The attending clinician will manage the patient according to the standard operating room practices, and data from both devices will only be recorded simultaneously and matched for subsequent statistical analysis.
Eligibility
Inclusion Criteria:
- Female patients scheduled for elective laparoscopic gynecologic oncology surgery
- Aged between 18 and 75 years
- American Society of Anesthesiologists (ASA) physical status I-III
- Patients who provide written and verbal informed consent
Exclusion Criteria:
- Known history of neuromuscular disease
- Severe hepatic or renal insufficiency
- Body Mass Index (BMI) greater than 35 kg/m2
- Patient refusal to participate
