Postoperative AtelectasisNCT07753278
Fresh Gas Flow and Lung Ultrasonography in Laparoscopic Cholecystectomy
A study testing Low Fresh Gas Flow (0.5 L/min) and High Fresh Gas Flow (4 L/min) in people with Postoperative Atelectasis and Pulmonary Atelectasis, run by Adiyaman University at 1 site in Turkey (Türkiye).
Trial summary
This prospective randomized clinical trial aims to evaluate the effects of different fresh gas flow rates on postoperative pulmonary aeration using lung ultrasonography in patients undergoing elective laparoscopic cholecystectomy. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Postoperative Atelectasis, Pulmonary Atelectasis
- What is being tested?
- Low Fresh Gas Flow (0.5 L/min) and High Fresh Gas Flow (4 L/min)
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 120 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 15 Aug 2026to 15 Oct 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 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adults aged 18 years or older.
- American Society of Anesthesiologists (ASA) physical status I-II.
- Scheduled for elective laparoscopic cholecystectomy under general anesthesia.
- Able and willing to provide written informed consent.
Who cannot join
- Refusal to participate in the study.
- History of chronic respiratory disease, including severe asthma, chronic obstructive pulmonary disease (COPD), or bronchiolitis.
- History of alcohol or substance abuse.
- Intraoperative airway or respiratory complications during endotracheal intubation or surgery.
- Life-threatening postoperative complications.
- Patients with ASA physical status III or higher.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site
Adıyaman Training and Research Hospital
Adıyaman, 02100
Mehmet DURAN, MD, Associate Professor, +90 505 689 5404, md021979@hotmail.com
About this study
Official title: Evaluation of the Effects of Fresh Gas Flow Differences on the Lungs Using Ultrasonography in Laparoscopic Cholecystectomy Surgeries
This prospective randomized clinical trial aims to evaluate the effects of different fresh gas flow rates on postoperative pulmonary aeration using lung ultrasonography in patients undergoing elective laparoscopic cholecystectomy. Patients will be randomly assigned to receive either low-flow anesthesia (0.5 L/min) or high-flow anesthesia (4 L/min) during maintenance of general anesthesia. The primary objective is to compare postoperative lung ultrasound scores and the incidence of atelectasis between the two groups.
Read the detailed description
Pulmonary atelectasis is one of the most common postoperative pulmonary complications following general anesthesia. Fresh gas flow is an important component of inhalational anesthesia and may influence airway humidity, gas exchange, respiratory mechanics, and pulmonary physiology. Although low-flow anesthesia has recognized economic, environmental, and physiological advantages, the effect of different fresh gas flow rates on postoperative lung aeration has not been adequately investigated.
This prospective, randomized, parallel-group clinical trial will be conducted at Adıyaman University Training and Research Hospital. Adult patients scheduled for elective laparoscopic cholecystectomy under general anesthesia will be randomly allocated to either a low-flow group (0.5 L/min) or a high-flow group (4 L/min) after an initial fresh gas flow of 4 L/min for 8 minutes following endotracheal intubation. Standardized anesthesia management will be applied to all participants.
Postoperative lung ultrasonography will be performed 30 minutes after extubation in the post-anesthesia care unit. Lung Ultrasound Score (LUS) and the incidence of postoperative atelectasis will be compared between the study groups. The findings are expected to provide evidence regarding the effects of different fresh gas flow strategies on postoperative pulmonary outcomes and may contribute to optimizing intraoperative anesthesia management.
- Conditions
- Postoperative Atelectasis, Pulmonary Atelectasis
- Being tested
- Low Fresh Gas Flow (0.5 L/min), High Fresh Gas Flow (4 L/min)
- Keywords
- Fresh Gas Flow, Lung Ultrasound Score, Pulmonary Complications
- Medical subject headings
- Pulmonary Atelectasis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Low Fresh Gas Flow (0.5 L/min)Procedure or surgery
General anesthesia will be maintained using a fresh gas flow rate of 0.5 L/min after an initial fresh gas flow of 4 L/min for 8 minutes following endotracheal intubation.
High Fresh Gas Flow (4 L/min)Procedure or surgery
General anesthesia will be maintained using a fresh gas flow rate of 4 L/min after an initial fresh gas flow of 4 L/min for 8 minutes following endotracheal intubation.
| Study group | Role | What they receive |
|---|---|---|
| Low Fresh Gas Flow | Active comparator | Participants will receive general anesthesia with a fresh gas flow rate of 0.5 L/min during the maintenance phase following an initial fresh gas flow of 4 L/min for 8 minutes after endotracheal intubation. Postoperative lung ultrasonography will be performed 30 minutes after extubation. Receives: Procedure: Low Fresh Gas Flow (0.5 L/min) |
| High Fresh Gas Flow | Active comparator | Participants will receive general anesthesia with a fresh gas flow rate of 4 L/min during the maintenance phase following an initial fresh gas flow of 4 L/min for 8 minutes after endotracheal intubation. Postoperative lung ultrasonography will be performed 30 minutes after extubation. Receives: Procedure: High Fresh Gas Flow (4 L/min) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Postoperative Lung Ultrasound Score
Lung ultrasonography will be performed 30 minutes after extubation. Both lungs will be divided into 12 regions, with 6 regions assessed in each lung. Each region will be scored from 0 to 3: 0 indicates normal aeration with A-lines or fewer than three B-lines; 1 indicates at least three well-spaced B-lines; 2 indicates coalescent B-lines; and 3 indicates lung consolidation. The scores from all regions will be summed, resulting in a total score ranging from 0 to 36. Higher scores indicate greater loss of lung aeration.
Measured: 30 minutes after extubation
Secondary outcomes (5)
Incidence of postoperative atelectasis
Atelectasis will be defined as a consolidation score ≥2 in any lung region assessed by lung ultrasonography
Measured: 30 minutes after extubation
Peripheral oxygen saturation (SpO₂)
Measured: During surgery
Mean arterial pressure
Measured: During surgery
Heart rate
Measured: During surgery
Peak airway pressure
Peak airway pressure will be recorded during general anesthesia and compared between the low and high fresh gas flow groups.
Measured: Throughout the intraoperative period
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 Aug 2026
- Study start15 Aug 2026 (estimated)
- Primary completion15 Oct 2026 (estimated)
- Study completion15 Oct 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Postoperative AtelectasisStudies of the same condition, open and under way.
- 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
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants will be randomly assigned in a 1:1 ratio to either the low fresh gas flow group (0.5 L/min) or the high fresh gas flow group (4 L/min). Each participant will receive only one intervention throughout the study, and postoperative lung ultrasound findings will be compared between the two parallel groups.
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 120 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Adiyaman University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, MEHMET DURAN, Adiyaman University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07753278
- Sponsor's protocol ID
- AH-AR-MD-01
- Status last verified
- Aug 2026
- First submitted
- 4 Aug 2026
- Last updated
- 7 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- 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 7 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of the Effects of Fresh Gas Flow Differences on the Lungs Using Ultrasonography in Laparoscopic Cholecystectomy Surgeries
- ClinicalTrials.gov ID
- NCT07753278
- Acronym / sponsor ID
- AH-AR-MD-01
- Conditions
- Postoperative Atelectasis, Pulmonary Atelectasis
- Keywords
- Fresh Gas Flow, Lung Ultrasound Score, Pulmonary Complications
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 120 participants (estimated)
- Lead sponsor
- Adiyaman UniversityUniversity, hospital or other
- Study start
- 15 Aug 2026 (estimated)
- Primary completion
- 15 Oct 2026 (estimated)
- Study completion
- 15 Oct 2026 (estimated)
- First posted
- 7 Aug 2026 (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 prospective randomized clinical trial aims to evaluate the effects of different fresh gas flow rates on postoperative pulmonary aeration using lung ultrasonography in patients undergoing elective laparoscopic cholecystectomy. Patients will be randomly assigned to receive either low-flow anesthesia (0.5 L/min) or high-flow anesthesia (4 L/min) during maintenance of general anesthesia. The primary objective is to compare postoperative lung ultrasound scores and the incidence of atelectasis between the two groups.
Detailed description
Pulmonary atelectasis is one of the most common postoperative pulmonary complications following general anesthesia. Fresh gas flow is an important component of inhalational anesthesia and may influence airway humidity, gas exchange, respiratory mechanics, and pulmonary physiology. Although low-flow anesthesia has recognized economic, environmental, and physiological advantages, the effect of different fresh gas flow rates on postoperative lung aeration has not been adequately investigated.
This prospective, randomized, parallel-group clinical trial will be conducted at Adıyaman University Training and Research Hospital. Adult patients scheduled for elective laparoscopic cholecystectomy under general anesthesia will be randomly allocated to either a low-flow group (0.5 L/min) or a high-flow group (4 L/min) after an initial fresh gas flow of 4 L/min for 8 minutes following endotracheal intubation. Standardized anesthesia management will be applied to all participants.
Postoperative lung ultrasonography will be performed 30 minutes after extubation in the post-anesthesia care unit. Lung Ultrasound Score (LUS) and the incidence of postoperative atelectasis will be compared between the study groups. The findings are expected to provide evidence regarding the effects of different fresh gas flow strategies on postoperative pulmonary outcomes and may contribute to optimizing intraoperative anesthesia management.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
- Model description
- Participants will be randomly assigned in a 1:1 ratio to either the low fresh gas flow group (0.5 L/min) or the high fresh gas flow group (4 L/min). Each participant will receive only one intervention throughout the study, and postoperative lung ultrasound findings will be compared between the two parallel groups.
| Arm | Type | Receives |
|---|---|---|
| Low Fresh Gas Flow | Active comparator | Procedure: Low Fresh Gas Flow (0.5 L/min)Participants will receive general anesthesia with a fresh gas flow rate of 0.5 L/min during the maintenance phase following an initial fresh gas flow of 4 L/min for 8 minutes after endotracheal intubation. Postoperative lung ultrasonography will be performed 30 minutes after extubation. |
| High Fresh Gas Flow | Active comparator | Procedure: High Fresh Gas Flow (4 L/min)Participants will receive general anesthesia with a fresh gas flow rate of 4 L/min during the maintenance phase following an initial fresh gas flow of 4 L/min for 8 minutes after endotracheal intubation. Postoperative lung ultrasonography will be performed 30 minutes after extubation. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Adults aged 18 years or older.
- American Society of Anesthesiologists (ASA) physical status I-II.
- Scheduled for elective laparoscopic cholecystectomy under general anesthesia.
- Able and willing to provide written informed consent.
Key exclusion criteria (6 listed)
- Refusal to participate in the study.
- History of chronic respiratory disease, including severe asthma, chronic obstructive pulmonary disease (COPD), or bronchiolitis.
- History of alcohol or substance abuse.
- Intraoperative airway or respiratory complications during endotracheal intubation or surgery.
- Life-threatening postoperative complications.
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 |
|---|---|---|
| Low Fresh Gas Flow (0.5 L/min)General anesthesia will be maintained using a fresh gas flow rate of 0.5 L/min after an initial fresh gas flow of 4 L/min for 8 minutes following endotracheal intubation. | Procedure or surgery | Low Fresh Gas Flow |
| High Fresh Gas Flow (4 L/min)General anesthesia will be maintained using a fresh gas flow rate of 4 L/min after an initial fresh gas flow of 4 L/min for 8 minutes following endotracheal intubation. | Procedure or surgery | High Fresh Gas Flow |
Primary outcome
Postoperative Lung Ultrasound Score
Time frame: 30 minutes after extubation
Lung ultrasonography will be performed 30 minutes after extubation. Both lungs will be divided into 12 regions, with 6 regions assessed in each lung. Each region will be scored from 0 to 3: 0 indicates normal aeration with A-lines or fewer than three B-lines; 1 indicates at least three well-spaced B-lines; 2 indicates coalescent B-lines; and 3 indicates lung consolidation. The scores from all regions will be summed, resulting in a total score ranging from 0 to 36. Higher scores indicate greater loss of lung aeration.
5 secondary outcomes
Incidence of postoperative atelectasis
Time frame: 30 minutes after extubation
Peripheral oxygen saturation (SpO₂)
Time frame: During surgery
Mean arterial pressure
Time frame: During surgery
Heart rate
Time frame: During surgery
Peak airway pressure
Time frame: Throughout the intraoperative period
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 7 Aug 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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Low Fresh Gas Flow (0.5 L/min) and High Fresh Gas Flow (4 L/min) in people with Postoperative Atelectasis and Pulmonary Atelectasis, run by Adiyaman University at 1 site in Turkey (Türkiye).
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 6 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: opening soon, as of the sponsor's last update on 7 Aug 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 Turkey (Türkiye). 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?
Contact MEHMET DURAN, MD, Associate Professor (+90 505 689 5404, md021979@hotmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Postoperative Lung Ultrasound Score (time frame: 30 minutes after extubation). 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 7 Aug 2026.