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

Official title

Optimal Interval for Periodic Alveolar Recruitment Maneuvers Achieving 90% Lung Re-expansion During Intraoperative Mechanical Ventilation: A Randomized Biased-Coin Sequential Trial

Overview

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.

Detailed description

This study is designed to evaluate the optimal interval of periodic alveolar recruitment maneuvers (PARM) to achieve effective lung re-expansion (defined as LUS ≤1 and shunt fraction \<10%) in 90% of elderly patients undergoing laparoscopic anterior resection in low Trendelenburg position. This is a single-arm, biased-coin sequential design study. The initial PARM interval is 30 min, adjusted in 10 min increments based on response. The primary outcome is recruitment efficacy. Secondary outcomes include intraoperative mechanical power, P/F ratio, postoperative pulmonary complications, and length of hospital stay. This study aims to inform optimal RM intervals in protective ventilation protocols.

Interventions

• Procedure Different interval of PARM
  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 unchange

Primary outcome measures

• The effectiveness of recruitment [Time frame: Intraoperative]

Secondary outcome measures (12)

• Mechanical power at the end of surgery [Time frame: 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 [Time frame: During intraoperative mechanical ventilation]
• The P/F ratio at the end of surgery, [Time frame: 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 [Time frame: 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 [Time frame: 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)]
• Intraoperative hypotension [Time frame: During mechanical ventilation in the intraoperative period.]
• Intraoperative vasopressor use. [Time frame: During intraoperative mechanical ventilation]
• Intraoperative mild hypoxemia [Time frame: During intraoperative mechanical ventilation]
• Intraoperative severe hypoxemia [Time frame: During intraoperative mechanical ventilation]
• Lung ultrasound score (LUS) in the post-anesthesia care unit (PACU) [Time frame: Awake with spontaneous breathing before discharge from the PACU]
• Rate of respiratory failure at post-anesthesia care unit (PACU) [Time frame: Stay in the PACU for at least 20 minutes and at most 3 hours; assessed at 5 to 10 minutes before leaving PACU]
• Rate of postoperative respiratory failure [Time frame: Day1 to 5 after surgery]

Eligibility criteria

Inclusion criteria

• 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%

Exclusion criteria

• 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

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

N/A

Model

Sequential

Masking

Open label

Primary purpose

Prevention

Study locations

China · 1 center

• SixthSunYetSen — Guangzhou

Identifiers

NCT: NCT07239557 · E2025034

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗