Optimal Interval for Periodic Alveolar Recruitment Maneuvers Achieving 90% Lung Re-expansion During Intraoperative Ventilation

NCT07239557 | Enrolling By Invitation DMC

• 1 other identifier: E2025034
• Study Type: interventional
• Target: 52
• Locations: 1 country
• Sites: 1

Brief Summary

This study aims to determine the optimal interval for periodic alveolar recruitment maneuvers (PARM) that can achieve effective lung re-expansion in 90% of patients undergoing intraoperative mechanical ventilation during abdominal laparoscopic surgery in the low Trendelenburg position. Identifying the most effective frequency of PARM is crucial for establishing lung-protective ventilation strategies, with the ultimate goal of reducing intraoperative atelectasis, decreasing postoperative pulmonary complications, and accelerating recovery. Patients are randomized using a biased-coin sequential design. PARM is initially applied every 0.5 hours, and the effectiveness of lung re-expansion is evaluated before the end of surgery. The primary outcome is the effectiveness of recruitment, assessed by a combination of lung ultrasound scores and shunt fraction. Secondary outcomes include mechanical power at the end of surgery, time-weighted average mechanical power during ventilation, postoperative P/F ratio, dead space fraction, air test results, intraoperative adverse events, incidence of respiratory failure in the PACU and postoperative period, and postoperative length of stay. This trial is expected to provide robust evidence for defining the optimal RM interval in protective ventilation protocols for patients undergoing laparoscopic abdominal surgery, thereby contributing to improved perioperative respiratory outcomes.

Conditions

Major Abdominal Surgery; Atelectasis; Lung-protective Ventilation; Lung Ultrasound Score; Postoperative Pulmonary Complications

Keywords

Laparoscopy; Trendelenburg position; Major abdominal surgery; Mechanical ventilation; Periodic recruitment maneuvers; Lung recruitment strategy; Respiratory function; Lung-protective ventilation; Lung ultrasound score; Effective concentration for 90% (EC90)

Outcome Measures

Primary Outcomes (1)

• The effectiveness of recruitment

  The effectiveness of recruitment assessed by a combination of lung ultrasound scores and shunt fraction。At the end of surgery (with the patient in the supine position, after at least 5 minutes of apnea under mechanical ventilation without spontaneous breathing, and at the specified interval since the last recruitment maneuver), a lung ultrasound examination was performed. Lung re-expansion was considered effective if the 12-zone lung ultrasound score (LUS) was ≤1 per zone and the shunt fraction was \<10%.

  Intraoperative

Secondary Outcomes (19)

• Mechanical power at the end of surgery

  With the patient in the supine position, after at least 5 minutes of apnea under mechanical ventilation without spontaneous breathing, and at the specified interval since the last recruitment maneuver

• Time-weighted average mechanical power during surgery

  During intraoperative mechanical ventilation

• The P/F ratio at the end of surgery,

  At the end of surgery (with the patient in the supine position, after at least 5 minutes of apnea under mechanical ventilation without spontaneous breathing, and at the specified interval since the last recruitment maneuver)

• Dead space rate

  At the end of surgery (with the patient in the supine position, after at least 5 minutes of apnea under mechanical ventilation without spontaneous breathing, and at the specified interval since the last recruitment maneuver)

• Air-breathing test

  At the end of surgery (with the patient in the supine position, after at least 5 minutes of apnea under mechanical ventilation without spontaneous breathing, and at the specified interval since the last recruitment maneuver)

Study Arms (1)

PARM

EXPERIMENTAL

Procedure: Different interval of PARM

Interventions

Different interval of PARM PROCEDURE

The initial time interval of PARM was 0.5 hours/time, and the different interval of PARM was assigned by random partial coin sequential method.If the previous patient did not respond to postoperative assessment of lung opening, the interval between expansion of the lungs was shortened by 10 minutes for the next patient; If lung opening is effective, there is an 11% chance that the next patient will have an 10-minute expansion interval and an 89% chance that the time interval will remain unchanged.

PARM

Eligibility Criteria

• Age: 65 Years - 80 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Older Adult (65+)

You may qualify if:

• Age 65-80 years
• Undergoing elective laparoscopic anterior resection (expected mechanical ventilation duration 2-5 hours)
• Intermediate risk for postoperative pulmonary complications
• Room air SpO₂ ≥94%

You may not qualify if:

• History of pneumonia within 1 month or mechanical ventilation ≥1 hour
• Preoperative 12-zone LUS with any single zone score ≥2
• Preoperative shunt fraction ≥10%
• Progressive neuromuscular disease
• Severe emphysema/COPD or subpleural bullae ≥2 cm
• Intracranial hypertension
• Participation in other studies or refusal to participate

Sponsors & Collaborators

• Sixth Affiliated Hospital, Sun Yat-sen University: lead

Study Sites (1)

SixthSunYetSen

Guangzhou, Guangdong, 510600, China

Location

MeSH Terms

Conditions

Pulmonary Atelectasis; Respiratory Aspiration

Condition Hierarchy (Ancestors)

Lung Diseases; Respiratory Tract Diseases; Respiration Disorders; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: SEQUENTIAL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: September 25, 2025
• First Posted: November 20, 2025
• Study Start: December 10, 2025
• Primary Completion (Estimated): December 31, 2026
• Study Completion (Estimated): December 31, 2026
• Last Updated: May 15, 2026

Record last verified: 2026-05

Data Sharing

• IPD Sharing: Will not share

Locations

CN (1)