Novel SaCoVLM™ Video Laryngeal Mask Airway as an Intubation Conduit in Morbidly Obese Bariatric Surgery

Novel SaCoVLM™ Video Laryngeal Mask Airway as an Intubation Conduit in Morbidly Obese Bariatric Surgery: a Single-arm Prospective Study

Background: The SaCoVLM™ video laryngeal mask is a novel video-assisted device that integrates the functions of both a dual-channel laryngeal mask airway (LMA) and an intubating laryngeal mask airway (ILMA). At present, there are relatively few studies on awake airway management for obese patients who undergo laparoscopic sleeve gastrectomy (LSG). To evaluate the efficacy and safety of the SaCoVLM™ video laryngeal mask airway as an intubation conduit in morbidly obese patients undergoing laparoscopic sleeve gastrectomy.

Patients and methods: This single-arm prospective study evaluated the efficacy and safety of the SaCoVLM™ video laryngeal mask airway in 57 morbidly obese patients (BMI ≥35 kg/m²) undergoing LSG.

Study Overview

• Status: Completed
• Conditions: Obesity; Morbidly Obese
• Intervention / Treatment: Device: SaCoVLM™ in Difficult Airways; Device: SaCoVLM™ in Difficult Airways

Detailed Description

All anesthesiologists in this study underwent centralized training prior to trial initiation, with documented certification in protocol-specific procedures. No preoperative medications were administered to any patients. Upon entering the operating room, patients were positioned in a semi-fowler position, with intravenous access established. Standard monitoring protocols were implemented, including electrocardiography (ECG), heart rate (HR), non-invasive blood pressure (NIBP), pulse oximetry (SpO₂), end-tidal carbon dioxide (EtCO₂), and bispectral index (BIS), alongside radial artery catheterization for invasive blood pressure monitoring. All patients underwent awake insertion of the SaCoVLM™, with surgery completed under general anesthesia combining the video laryngeal mask and endotracheal intubation.

Immediately upon arrival in the operating room, patients were instructed to hold 10 mL of dyclonine mucilage orally for approximately 10 minutes to achieve topical anesthesia. Premedication included midazolam 2 mg and atropine 0.4 mg, followed by bilateral ultrasound-guided superior laryngeal nerve block using 0.375% ropivacaine. A properly sized laryngeal mask was selected, and under awake conditions, patients were instructed to open their mouths to facilitate SaCoVLM™. Optimal positioning was confirmed by visualization of complete glottic structures on the monitor screen. The glottic exposure grade was as we previously described. The cuff was inflated using a handheld manometer, and the mask was connected to the anesthesia machine. Clear glottic visualization on the monitor and the presence of a regular EtCO₂ waveform confirmed proper mask alignment, after which rapid anesthesia induction was initiated.

If suboptimal positioning occurred, the up-down maneuver, cricoid pressure, cuff pressure adjustment, fiberoptic bronchoscopy-guided intubation were applied for minor adjustments. Under direct video guidance, the endotracheal tube was gently advanced along the natural curvature of the airway. Successful intubation was defined by unimpeded tube passage, direct visualization of tracheal entry, and sustained EtCO₂ waveform. Following intubation, the breathing circuit was immediately connected, and bilateral lung auscultation confirmed symmetrical breath sounds before securing both the mask and endotracheal tube. Intraoperative fluid administration and vasoactive medications were adjusted based on vital signs, urine output, and physiological requirements.

Postoperatively, the endotracheal tube was removed under deep anesthesia, and the video laryngeal mask was retained for transfer to the post-anesthesia care unit (PACU). The laryngeal mask was removed only after patients regained adequate spontaneous respiration, demonstrated responsiveness to verbal commands, and met established extubation criteria.

• Study Type: Observational
• Enrollment (Actual): 57

Contacts and Locations

Study Locations

• China
  • Shandong
    • Jinan, Shandong, China, 250014
      • The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Probability Sample

Study Population

The study population comprised adult patients aged over 18 years (with no upper age limit) diagnosed with morbid obesity.

Description

Inclusion Criteria:

1. Adult patients aged over 18 years (no upper age limit)
2. Diagnosed with morbid obesity, clinically defined as either:

Body mass index (BMI) ≥ 40 kg/m², or BMI ≥ 35 kg/m² accompanied by at least one significant obesity-related comorbidity

Exclusion Criteria:

1. Have no clinical indicators of anticipated difficult airway (Mallampati classification IV, thyromental distance < 6 cm, mouth opening < 3 cm, severe limited neck extension, or a history of difficult airway management)
2. Demonstrate tolerance for laparoscopic surgery and anesthesia
3. Be scheduled exclusively for LSG without concurrent additional procedures

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

morbidly obese bariatric surgery; This study was a single-arm prospective study, so there was no grouping.

Device: SaCoVLM™ in Difficult Airways; As part of the awake airway management protocol initiated in the operating room, patients were first instructed to hold 10 mL of dyclonine mucilage orally for approximately 10 minutes to achieve topical oropharyngeal anesthesia. This was followed by intravenous administration of midazolam 2 mg and atropine 0.4 mg, and bilateral ultrasound-guided superior laryngeal nerve block using 0.375% ropivacaine. A properly sized laryngeal mask was selected. The posterior surface of the cuff was lubricated with a water-based surgical lubricant. Under awake conditions, patients were instructed to open their mouths to facilitate SaCoVLM™ insertion. Optimal positioning was confirmed by visualization of complete glottic structures on the monitor screen. The glottic exposure grade was as we previously described . The cuff was inflated using a handheld manometer, and the mask was connected to the anesthesia machine. Clear glottic visualization on the monitor and the presence of a regular EtCO₂ waveform.; Device: SaCoVLM™ in Difficult Airways; As part of the awake airway management protocol initiated in the operating room, patients were first instructed to hold 10 mL of dyclonine mucilage orally for approximately 10 minutes to achieve topical oropharyngeal anesthesia. This was followed by intravenous administration of midazolam 2 mg and atropine 0.4 mg, and bilateral ultrasound-guided superior laryngeal nerve block using 0.375% ropivacaine. A properly sized laryngeal mask was selected. The posterior surface of the cuff was lubricated with a water-based surgical lubricant. Under awake conditions, patients were instructed to open their mouths to facilitate SaCoVLM™ insertion. Optimal positioning was confirmed by visualization of complete glottic structures on the monitor screen. The glottic exposure grade was as we previously described. The cuff was inflated using a handheld manometer, and the mask was connected to the anesthesia machine. Clear glottic visualization on the monitor and the presence of a regular EtCO₂ waveform.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
the first-time success rate of intubation after insertion of SaCoVLM™	Within 10 minutes following SaCoVLM™ placement

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time to Successful SaCoVLM™ Insertion (seconds)	Time to successful insertion is measured in seconds as a continuous time-to-event variable. Successful insertion is defined as proper placement of the SaCoVLM™ with visible chest rise and a square-wave capnography trace. Shorter time indicates a better outcome (faster airway establishment). The primary metric reported will be the median insertion time with interquartile range, along with the proportion of successful insertions within 60, 90, and 120 seconds.	From the start of device insertion into the mouth until the time of successful SaCoVLM™ placement with first confirmed ventilation, assessed up to 120 seconds. If insertion is not successful within 120 seconds, the event is censored at 120 seconds.
Number of SaCoVLM™ Insertion Attempts per Participant	An insertion attempt is defined as any entry of the SaCoVLM™ into the patient's mouth with the intention of placement, regardless of depth or success. Each withdrawal of the device from the mouth followed by re-entry counts as a new attempt. The total number of attempts required to achieve successful placement (confirmed by end-tidal CO₂ waveform) is recorded. Fewer attempts indicate a better outcome (easier insertion). The primary metric reported will be the mean (or median) number of attempts, the range, and the proportion of participants requiring 1, 2, or ≥3 attempts.	From the first insertion attempt until successful SaCoVLM™ placement is achieved or until the procedure is abandoned, assessed during the initial airway management procedure (up to 120 seconds or a maximum of 3 attempts, whichever comes first).
the SaCoVLM™ glottic exposure grades		Immediately after SaCoVLM™ placement
Oropharyngeal Leak Pressure (OLP) (cm H₂O)	OLP is measured by closing the adjustable pressure limiting valve of the anesthesia circuit while maintaining a fixed gas flow of 3 L/min. The airway pressure at which an audible leak occurs around the device (or the pressure at which the capnography waveform flattens) is recorded as the OLP in cm H₂O. Higher OLP indicates a better seal and is considered a better outcome (more effective supraglottic airway seal). The primary metric reported will be the mean (or median) OLP with standard deviation or interquartile range.	Immediately after successful SaCoVLM™ insertion and before start of positive pressure ventilation (measured at a single time point: within 1 minute of confirmation of correct placement)
Proportion of Participants Requiring Any Airway Optimization Maneuver During SaCoVLM™ Placement	The airway optimization protocol includes predefined maneuvers to improve ventilation or seal when SaCoVLM™ placement is suboptimal (e.g., audible leak >30 cm H₂O, absent capnography, or inability to ventilate). Recorded maneuvers may include: chin lift, jaw thrust, head extension/flexion, device rotation, partial withdrawal and reinsertion, or changing to a different size/type of supraglottic airway. The primary outcome metric is the proportion of participants requiring any optimization maneuver during the specified time frame. Secondary metrics include the number of different maneuvers used per participant and the specific maneuvers most frequently applied. No numerical scale is used; this is a descriptive/binary outcome (optimization required: yes/no). Fewer required maneuvers indicate a better outcome (easier device placement).	During the initial airway management procedure, from the start of the first insertion attempt until successful ventilation is confirmed (assessed up to 120 seconds or a maximum of 3 attempts).
Incidence and Severity of Postoperative Sore Throat (POST) as Assessed by a 4-Point Scale	POST is measured using a 4-point categorical scale: 0 = no sore throat; = mild sore throat (complains only when asked); = moderate sore throat (complains spontaneously); = severe sore throat (hoarseness or difficulty swallowing) Minimum value = 0, maximum value = 3. Higher scores indicate a worse outcome (more severe sore throat). The primary metrics reported will be: Incidence = proportion of participants with any POST (score ≥1) at the specified time point Severity = mean (or median) score at each time point, plus the proportion with severe POST (score 3)	At 72 hours after the end of surgery
Incidence and Severity of Postoperative Hoarseness as Assessed by a 4-Point Scale	Postoperative hoarseness is measured using a 4-point categorical scale: 0 = no hoarseness (voice normal); = mild hoarseness (voice slightly different but able to speak without difficulty); = moderate hoarseness (voice obviously changed, speaking with effort); = severe hoarseness (voice barely audible or aphonic)	At 24 hours after the end of surgery
Number of Participants with Treatment-Emergent Adverse Events (TEAEs)	Adverse events (AEs) are defined according to [specify system, e.g., Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 or a standardized surgical complication list]. AEs include, but are not limited to: hypoxia, bradycardia, hypotension, laryngospasm, bronchospasm, dental trauma, bleeding, and allergic reaction. Each AE is graded for severity (mild/moderate/severe) and relationship to the procedure. The primary metric reported will be the proportion of participants experiencing at least one AE during the specified time frame. Secondary metrics include the total number of AEs, type and frequency of specific AEs, and proportion of severe AEs. No scale is used for the primary binary outcome; severity grading follows CTCAE (Grade 1-5, where higher grade = worse outcome).	From the end of surgery until 72 hours postoperatively

Collaborators and Investigators

• Sponsor: Yongtao Sun
• Investigators: Principal Investigator: Yongtao Sun, Shandong First Medical University; Study Chair: Min Zhang, Shandong First Medical University

Publications and helpful links

General Publications

• Davies MJ, D'Alessio DA, Fradkin J, Kernan WN, Mathieu C, Mingrone G, Rossing P, Tsapas A, Wexler DJ, Buse JB. Management of Hyperglycemia in Type 2 Diabetes, 2018. A Consensus Report by the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD). Diabetes Care. 2018 Dec;41(12):2669-2701. doi: 10.2337/dci18-0033. Epub 2018 Oct 4.
• Arterburn DE, Telem DA, Kushner RF, Courcoulas AP. Benefits and Risks of Bariatric Surgery in Adults: A Review. JAMA. 2020 Sep 1;324(9):879-887. doi: 10.1001/jama.2020.12567.
• Harjai M, Alam S, Rastogi S, Kumar S. Effectiveness and Validity of Preoperative Ultrasonographic Airway Assessment and Clinical Screening Tests to Predict Difficult Laryngoscopy: A Prospective, Observational Study. Cureus. 2023 Jul 15;15(7):e41933. doi: 10.7759/cureus.41933. eCollection 2023 Jul.
• Wang Y, Zhao L, Gao L, Pan A, Xue H. Health policy and public health implications of obesity in China. Lancet Diabetes Endocrinol. 2021 Jul;9(7):446-461. doi: 10.1016/S2213-8587(21)00118-2. Epub 2021 Jun 4.

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2022
• Primary Completion (Actual): May 20, 2023
• Study Completion (Actual): May 30, 2023

Study Registration Dates

• First Submitted: April 6, 2026
• First Submitted That Met QC Criteria: May 1, 2026
• First Posted (Actual): May 7, 2026

Study Record Updates

• Last Update Posted (Actual): May 7, 2026
• Last Update Submitted That Met QC Criteria: May 1, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Airway management; Laparoscopic sleeve gastrectomy; Morbidly obese patients; Video laryngeal mask airway; First-attempt success rate
• 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: YXLL-KY-2022 035; 320.6750.2024-15-19 (Other Grant/Funding Number: Wu Jie-ping Medical Foundation)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: all IPD collected throughout the trial, only IPD used in the results publication
• IPD Sharing Time Frame: From May 2022 to May 2023, we included a total of 57 patients who were scheduled to undergo bariatric surgery.

IPD Sharing Access Criteria

Who Qualified researchers from academic, non-profit, or commercial institutions with an approved research proposal; regulatory authorities; and direct collaborators.

What Anonymized IPD, data dictionary, protocol, SAP, and ICF summary. No direct or indirect participant identifiers.

How

Submit proposal via online portal.

Independent review committee approval.

Sign data use agreement (non-identification, non-commercial, no third-party sharing).

Access via secure virtual research environment or encrypted download; time-limited (e.g., 12 months); audit logs kept.

• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE; CSR

Drug and device information, study documents

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