Low-Intensity Mechanical Ventilation in the Operating Room: a Pilot Study (VIOLET)

August 20, 2026 updated by: Maximilian S Schaefer, Beth Israel Deaconess Medical Center
The aim of the study is to assess whether a bundle of protective low-intensity mechanical ventilation interventions reduces perioperative atelectasis and postoperative pulmonary complications, compared with standard care in a robot-assisted surgical setting. The feasibility of this ventilation bundle will also be assessed.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Enrolling by invitation

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The investigators hypothesize that protective low-intensity mechanical ventilation during robot-assisted surgery reduces perioperative atelectasis and postoperative pulmonary complications.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
60

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • Massachusetts
      • Boston, Massachusetts, United States, 02115
        • Beth Israel Deaconess Medical Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Adult patients undergoing non-emergent intra-abdominal or pelvic robot-assisted surgery with an expected duration of at least 2 hours, under general anesthesia with planned extubation at the end of the procedure

Exclusion Criteria:

  • Known pregnancy
  • Pre-existing intubation or tracheostomy
  • Contraindications for esophageal manometry: severe midface trauma or recent nasal surgery, esophageal varices, recent gastric or esophageal surgery
  • Contraindications for electrical impedance tomography (EIT): inability to place EIT belt, presence of an active electronic implantable device (e.g., pacemaker, ICD)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
No Intervention: Control
A guided standard of care protocol will be applied in the control group. This includes a PEEP of 5 cmH₂O, with adjustment by the anesthesia provider if SpO₂ falls below 96% or whenever deemed clinically necessary, a tidal volume of 6-10 mL/kg predicted body weight, and a respiratory rate adjusted to maintain end-tidal CO₂ between 35 and 45 mmHg throughout anesthesia. FiO₂ will be set to 100% during the washout phase at the end of surgery to limit resorption atelectasis.
Experimental: Intervention
A bundle of protective low-intensity mechanical ventilation strategies will be applied throughout the procedure. All interventions consist of modification of ventilator settings.
Device: Low Intensity Mechanical Ventilation

A bundle of protective low-intensity mechanical ventilation strategies will be applied throughout the procedure:

  1. Recruitment maneuver
  2. Tidal volume set to 8 ml/kg predicted body weight (PBW) and stepwise adjustment to achieve a driving pressure (Plateau pressure - PEEP) < 13 cmH2O with a minimum tidal volume of 5ml/kg PBW
  3. Respiratory rate adjustment to maintain a target end-tidal carbon dioxide concentration (etCO₂) between 45 and 55 mmHg.
  4. Reassessment and adaptation after Trendelenburg positioning and pneumoperitoneum.
  5. Re-adjustment of Tidal Volume and PEEP ventilator settings to (2.) after exsufflation and return to the supine position. FiO₂ set to 70% during the washout phase of the inhalational anesthetic until extubation.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
ΔEELV between baseline and after extubation before leaving the operating room.
Time Frame: Perioperative Day 0: From pre-intubation baseline in the operating room (prior to induction of anesthesia) to the first post-extubation EIT assessment (within 10 min after extubation on Day 0).
Change in end-expiratory lung volume (EELV), measured using electrical impedance tomography between baseline and after extubation before leaving the operating room.
Perioperative Day 0: From pre-intubation baseline in the operating room (prior to induction of anesthesia) to the first post-extubation EIT assessment (within 10 min after extubation on Day 0).

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Recruitment rate
Time Frame: Day 0
Proportion of patients enrolled in the study-defined as those who provided acceptance and signed informed consent-relative to all patients approached.
Day 0
Intervention deliverability
Time Frame: From intubation to extubation at Day 0
proportion of patients in the intervention arm in whom the full bundle of protective low-intensity ventilation strategies is delivered as planned across all predefined intraoperative phases.
From intubation to extubation at Day 0
EELV
Time Frame: Perioperative Day 0: before anesthesia, after intubation, after PEEP/TV/RR titration, after insufflation and positioning, after PEEP/TV/RR reassessment, just before extubation, after extubation, after PACU admission and 60min after PACU admission
End-expiratory lung volume measured by Electrical Impedance Tomography in mL
Perioperative Day 0: before anesthesia, after intubation, after PEEP/TV/RR titration, after insufflation and positioning, after PEEP/TV/RR reassessment, just before extubation, after extubation, after PACU admission and 60min after PACU admission
COV
Time Frame: Perioperative Day 0: before anesthesia, after intubation, after PEEP/TV/RR titration, after insufflation and positioning, after PEEP/TV/RR reassessment, just before extubation, after extubation, after PACU admission and 60min after PACU admission
Center of ventilation measured by Electrical Impedance Tomography in percentage
Perioperative Day 0: before anesthesia, after intubation, after PEEP/TV/RR titration, after insufflation and positioning, after PEEP/TV/RR reassessment, just before extubation, after extubation, after PACU admission and 60min after PACU admission
RVDI
Time Frame: Perioperative Day 0: before anesthesia, after intubation, after PEEP/TV/RR titration, after insufflation and positioning, after PEEP/TV/RR reassessment, just before extubation, after extubation, after PACU admission and 60min after PACU admission
Regional ventilation delay inhomogeneity measured by Electrical Impedance Tomography (unitless)
Perioperative Day 0: before anesthesia, after intubation, after PEEP/TV/RR titration, after insufflation and positioning, after PEEP/TV/RR reassessment, just before extubation, after extubation, after PACU admission and 60min after PACU admission
GI
Time Frame: Perioperative Day 0: before anesthesia, after intubation, after PEEP/TV/RR titration, after insufflation and positioning, after PEEP/TV/RR reassessment, just before extubation, after extubation, after PACU admission and 60min after PACU admission
Global inhomogeneity index measured by Electrical Impedance Tomography (unitless)
Perioperative Day 0: before anesthesia, after intubation, after PEEP/TV/RR titration, after insufflation and positioning, after PEEP/TV/RR reassessment, just before extubation, after extubation, after PACU admission and 60min after PACU admission
Dorsal ROI
Time Frame: Perioperative Day 0: before anesthesia, after intubation, after PEEP/TV/RR titration, after insufflation and positioning, after PEEP/TV/RR reassessment, just before extubation, after extubation, after PACU admission and 60min after PACU admission
Maximum dorsal ratio of impedance measured by Electrical Impedance Tomography (unitless)
Perioperative Day 0: before anesthesia, after intubation, after PEEP/TV/RR titration, after insufflation and positioning, after PEEP/TV/RR reassessment, just before extubation, after extubation, after PACU admission and 60min after PACU admission
EEPL
Time Frame: Perioperative Day 0: after intubation, after PEEP/TV/RR titration, after insufflation and positioning, after PEEP/TV/RR reassessment, just before extubation
End-expiratory transpulmonary pressure, calculated as airway pressure minus esophageal pressure (cmH₂O)
Perioperative Day 0: after intubation, after PEEP/TV/RR titration, after insufflation and positioning, after PEEP/TV/RR reassessment, just before extubation
EIPL
Time Frame: Perioperative Day 0: after intubation, after PEEP/TV/RR titration, after insufflation and positioning, after PEEP/TV/RR reassessment, just before extubation
End-inspiratory transpulmonary pressure, calculated as airway pressure minus esophageal pressure (cmH₂O)
Perioperative Day 0: after intubation, after PEEP/TV/RR titration, after insufflation and positioning, after PEEP/TV/RR reassessment, just before extubation
Relationship between body mass index with optimal PEEP
Time Frame: Intraoperative Day 0: after insufflation of pneumoperitoneum and positioning the patient for surgery
Correlation between BMI (kg/m²) and the optimal positive end-expiratory pressure (PEEP, cmH₂O) determined after pneumoperitoneum insufflation and patient positioning for surgery.
Intraoperative Day 0: after insufflation of pneumoperitoneum and positioning the patient for surgery
Relationship of the degree of Trendelenburg inclination with optimal PEEP
Time Frame: Intraoperative Day 0: after insufflation of pneumoperitoneum and positioning the patient for surgery
Correlation between the degree of Trendelenburg inclination (in degree) and the optimal positive end-expiratory pressure (PEEP, cmH₂O) determined after pneumoperitoneum insufflation and patient positioning for surgery.
Intraoperative Day 0: after insufflation of pneumoperitoneum and positioning the patient for surgery
Relationship of the pneumoperitoneum (insufflation) with optimal PEEP
Time Frame: Intraoperative Day 0: after insufflation of pneumoperitoneum and positioning the patient for surgery
Correlation between the pneumoperitoneum (insufflation in cmH2O) and the optimal positive end-expiratory pressure (PEEP, cmH₂O) determined after pneumoperitoneum insufflation and patient positioning for surgery.
Intraoperative Day 0: after insufflation of pneumoperitoneum and positioning the patient for surgery
Intraoperative oxygenation
Time Frame: Perioperative Day 0: before anesthesia, after intubation, after PEEP/TV/RR titration, after insufflation and positioning, after PEEP/TV/RR reassessment, just before extubation, after extubation
Intraoperative peripheral pulsed oxygen saturation (SpO2)
Perioperative Day 0: before anesthesia, after intubation, after PEEP/TV/RR titration, after insufflation and positioning, after PEEP/TV/RR reassessment, just before extubation, after extubation
Postoperative oxygenation
Time Frame: Postoperative Day 0: after PACU admission and 60min after PACU admission
Postoperative peripheral pulsed oxygen saturation (SpO2)
Postoperative Day 0: after PACU admission and 60min after PACU admission
Proportion of patients with postoperative pulmonary complications at day 7
Time Frame: This secondary outcome will be assessed in the time between day of surgery until 7 days after the day of surgery
Re-intubation, hypoxemia requiring oxygen therapy, pleural effusion, pneumonia, atelectasis or emergency non-invasive ventilation
This secondary outcome will be assessed in the time between day of surgery until 7 days after the day of surgery

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Beth Israel Deaconess Medical Center

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
April 2, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
October 31, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 31, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 20, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 2, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
December 11, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 21, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 20, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2025P000986

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings