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Enrolling by Invitation

NCT Number: NCT07277244

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

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.

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Key information

Conditions

Robotic Surgery Post Operative Pulmonary Complications

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Beth Israel Deaconess Medical Center

Boston, Massachusetts, 02115, United States

About this study

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

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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)

Treatment and study plan

Low Intensity Mechanical Ventilation

Device

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

  • Recruitment maneuver
  • 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
  • Respiratory rate adjustment to maintain a target end-tidal carbon dioxide concentration (etCO₂) between 45 and 55 mmHg.
  • Reassessment and adaptation after Trendelenburg positioning and pneumoperitoneum.
  • 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.

Primary outcomes

  1. 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.

Secondary outcomes

  1. 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

  2. Change in right-ventricular systolic function (TAPSE, mm) from pre-intubation baseline to first post-extubation echocardiogram

    Time frame: Perioperative Day 0: before anesthesia and after PEEP/TV/RR titration

    Right-ventricular systolic function will be assessed by transthoracic echocardiography using tricuspid annular plane systolic excursion (TAPSE, measured in millimeters). TAPSE will be recorded at pre-intubation baseline and at the first postoperative transthoracic echocardiographic examination after extubation. The primary outcome for this measure will be the change in TAPSE (post-extubation minus baseline, mm).

  3. Change in right-ventricular fractional area change (RV-FAC, %) from pre-intubation baseline to first post-extubation echocardiogram

    Time frame: Perioperative Day 0: before anesthesia and after PEEP/TV/RR titration

    Right-ventricular systolic function will be assessed by transthoracic echocardiography using right-ventricular fractional area change (RV-FAC, expressed as percentage). RV-FAC will be recorded at pre-intubation baseline and at the first postoperative transthoracic echocardiographic examination after extubation. The outcome for this measure will be the change in RV-FAC (post-extubation minus baseline, %).

  4. Change in left ventricular ejection fraction (LVEF, %) from pre-intubation baseline to first post-extubation echocardiogram

    Time frame: Perioperative Day 0: before anesthesia and after PEEP/TV/RR titration

    Left ventricular systolic function will be assessed by transthoracic echocardiography using left ventricular ejection fraction (LVEF, expressed as percentage). LVEF will be recorded at pre-intubation baseline and at the first postoperative transthoracic echocardiographic examination after extubation. The outcome for this measure will be the change in LVEF (post-extubation minus baseline, %).

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. 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)

  10. 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)

  11. 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)

  12. 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)

  13. 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)

  14. 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.

  15. 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.

  16. 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.

  17. 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)

  18. Postoperative oxygenation

    Time frame: Postoperative Day 0: after PACU admission and 60min after PACU admission

    Postoperative peripheral pulsed oxygen saturation (SpO2)

Sponsors and collaborators

Lead sponsor

Beth Israel Deaconess Medical Center

Other

Registry information

Acronym: VIOLET

Important dates

Study start
2026
Primary completion
2026
Study completion
2027
First posted
Dec 11, 2025
Registry last updated
Jun 2, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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