Major Abdominal SurgeryNCT07239557
Optimal Interval for Periodic Alveolar Recruitment Maneuvers Achieving 90% Lung Re-expansion During Intraoperative Ventilation
A study testing Different interval of PARM in people with Major Abdominal Surgery and Atelectasis, run by Sixth Affiliated Hospital, Sun Yat-sen University at 1 site in China.
Trial 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. Read more about this study
- Who is it for?
- Ages 65 to 80 years
- Conditions the study is for
- Major Abdominal Surgery, Atelectasis, Lung-protective Ventilation
- What is being tested?
- Different interval of PARM
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 52 participants
- Where
- 1 siteChina
- Study dates
- 10 Dec 2025to 31 Dec 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 65 to 80 years
- All sexes
- No healthy volunteers
- Older adult
Who may be able to join
- 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%
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Optimal Interval for Periodic Alveolar Recruitment Maneuvers Achieving 90% Lung Re-expansion During Intraoperative Mechanical Ventilation: A Randomized Biased-Coin Sequential Trial
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.
Read the 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.
- Conditions
- Major Abdominal Surgery, Atelectasis, Lung-protective Ventilation, Lung Ultrasound Score, Postoperative Pulmonary Complications
- Being tested
- Different interval of PARM
- 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)
- Medical subject headings
- Pulmonary Atelectasis, Respiratory Aspiration
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Different interval of PARMProcedure or surgery
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 group | Role | What they receive |
|---|---|---|
| PARM | Experimental | Not described Receives: Procedure: Different interval of PARM |
What is being measured
The primary outcome is the main question the study is designed to answer.
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%.
Measured: Intraoperative
Secondary outcomes (19)
Mechanical power at the end of surgery
Mean or median mechanical power
Measured: 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
Mechanical power per ventilation time
Measured: During intraoperative mechanical ventilation
The P/F ratio at the end of surgery,
P/F ratio = PaO₂ / FiO₂.Statistical measure: Incidence of P/F ratio ≤400. The P/F ratio is an objective research parameter, and a P/F ratio ≤400 indicates the presence of atelectasis.
Measured: 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
Arterial carbon dioxide partial pressure (PaCO2); partial pressure of carbon dioxide in end expiratory gas (PetCO2); Dead space fraction = (PaCO2-PetCO2)/ PaCO2.
Measured: 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
After completion of ultrasound and arterial blood gas measurements, the inspired oxygen concentration was adjusted to 21%. SpO₂ was observed and recorded after 5 minutes.The incidence of a positive air-breathing test, defined as SpO₂ ≤96%, was recorded
Measured: 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
Defined as mean arterial pressure (MAP) <60 mmHg from any cause, lasting for more than 3 minutes。
Measured: During mechanical ventilation in the intraoperative period.
Intraoperative vasopressor use.
Defined as any episode of MAP <60 mmHg during mechanical ventilation requiring the administration of catecholamine vasopressors, including dopamine, epinephrine, or norepinephrine. Occurrence of such an event was recorded as positive.
Measured: During intraoperative mechanical ventilation
Intraoperative mild hypoxemia
SpO₂ ≤96% lasting for more than 3 minutes
Measured: During intraoperative mechanical ventilation
Intraoperative severe hypoxemia
SpO₂ ≤92% lasting for more than 3 minutes
Measured: During intraoperative mechanical ventilation
Lung ultrasound score (LUS) in the post-anesthesia care unit (PACU)
The 12-zone lung ultrasound score (LUS) ranges from 0 to 3 per zone (total 0-36). Higher scores indicate more severe atelectasis.
Measured: Awake with spontaneous breathing before discharge from the PACU
Rate of respiratory failure at post-anesthesia care unit (PACU)
PaO₂/FiO₂ <300 mmHg, or PaO₂ <60 mmHg or SpO₂ <90% while awake and breathing room air.
Measured: 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
PaO₂/FiO₂ <300 mmHg, or PaO₂ <60 mmHg or SpO₂ <90% while awake and breathing room air.
Measured: Day1 to 5 after surgery
Rate of sustained hypoxaemia
Sustained hypoxaemia, hypoxaemia at any two consecutive days; hypoxaemia: during a follow-up visit when the patient was awake and breathing room air, SpO2 ≤ 92% or the change of SpO2 (ΔSpO2, preoperative SpO2 minus postoperative SpO2) ≥ 5%.
Measured: Day 1 to 5 after surgery
Postoperative pulmonary complications, Grades 1-4
Operational Definitions of Postoperative Pulmonary Complications (Doi: 10.1001/jama.296.15.1851), graded on a scale from 1 to 4.
Measured: Day 0 to 5 after surgery
Postoperative pulmonary complications, Grades 2-4
Operational Definitions of Postoperative Pulmonary Complications (Doi: 10.1001/jama.296.15.1851), graded on a scale from 2 to 4
Measured: Day 0 to 5 after surgery
Pneumothorax
Defined as the presence of air within the pleural cavity, with the visceral pleura not being surrounded by a vascular pattern.
Measured: Day 0 to 7 after surgery
Postoperative hospitalization days
The duration between the operation date and the actual discharge date.
Measured: Day 0 to 30 after surgery
Unexpected admission to ICU
It does not include the patients who enter ICU at the request of surgeons but have normal spontaneous breathing, stable circulation and no disturbance of consciousness.
Measured: within 30 days after surgery
Death from any cause
Intraoperative or postoperative death from any cause
Measured: Day 0 to 30 after surgery
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Nov 2025
- Study start10 Dec 2025
- Primary completion31 Dec 2026 (estimated)
- Study completion31 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Major Abdominal SurgeryStudies of the same condition, open and under way.
- More trials run by Sixth Affiliated Hospital, Sun Yat-sen UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Not applicable
- Intervention model
- Sequential
- Masking
- None (open label)
- Enrolment
- 52 participants (estimated)
Sponsor and investigators
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07239557
- Sponsor's protocol ID
- E2025034
- Status last verified
- May 2026
- First submitted
- 25 Sep 2025
- Last updated
- 15 May 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 15 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Optimal Interval for Periodic Alveolar Recruitment Maneuvers Achieving 90% Lung Re-expansion During Intraoperative Mechanical Ventilation: A Randomized Biased-Coin Sequential Trial
- ClinicalTrials.gov ID
- NCT07239557
- Acronym / sponsor ID
- E2025034
- 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
- Study type
- Interventional
- Recruitment status
- Enrolling by invitation
- Enrolment
- 52 participants (estimated)
- Lead sponsor
- Sixth Affiliated Hospital, Sun Yat-sen UniversityUniversity, hospital or other
- Study start
- 10 Dec 2025 (actual)
- Primary completion
- 31 Dec 2026 (estimated)
- Study completion
- 31 Dec 2026 (estimated)
- First posted
- 20 Nov 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Prevention
- Allocation
- Not applicable
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| PARM | Experimental | Procedure: Different interval of PARM |
Who may qualify
- Ages
- 65 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Older adult
Key inclusion criteria (4 listed)
- 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%
Key exclusion criteria (7 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Different interval of PARMThe 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. | Procedure or surgery | PARM |
Primary outcome
The effectiveness of recruitment
Time frame: 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%.
19 secondary outcomes
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
Rate of sustained hypoxaemia
Time frame: Day 1 to 5 after surgery
Postoperative pulmonary complications, Grades 1-4
Time frame: Day 0 to 5 after surgery
Postoperative pulmonary complications, Grades 2-4
Time frame: Day 0 to 5 after surgery
Pneumothorax
Time frame: Day 0 to 7 after surgery
Postoperative hospitalization days
Time frame: Day 0 to 30 after surgery
Unexpected admission to ICU
Time frame: within 30 days after surgery
Death from any cause
Time frame: Day 0 to 30 after surgery
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 May 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Different interval of PARM in people with Major Abdominal Surgery and Atelectasis, run by Sixth Affiliated Hospital, Sun Yat-sen University at 1 site in China.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 15 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
The effectiveness of recruitment (time frame: Intraoperative). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 May 2026.