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

Condition(s) studied

Investigational drug(s) / intervention(s)

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 unchanged.

Study 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.

Eligibility

Primary outcome measure(s)

• The effectiveness of recruitment — Intraoperative
  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%.

Trial sites (1)

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