Postoperative AtelectasisLUS-ATELECNCT07320092
Supine vs Prone Position and Atelectasis Assessed by Lung Ultrasound
An observational study of Postoperative Atelectasis, run by Istanbul University - Cerrahpasa at 1 site in Turkey (Türkiye).
Trial summary
Atelectasis frequently develops during and after general anesthesia due to factors such as anesthesia-induced diaphragmatic dysfunction, reduced functional residual capacity, altered ventilation-perfusion matching, and surgical positioning. Read more about this study
- Who is it for?
- Ages 18 to 80 yearsHealthy volunteers can take part
- Conditions the study is for
- Postoperative Atelectasis
- How many people
- 80 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 15 Sep 2025to 15 Apr 2026
- Phase
- Observational
- Are there results?
- None posted in the registry
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 80 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: The study population consists of adult patients aged 18 years and older who are scheduled to undergo elective surgical procedures under general anesthesia. Patients will be evaluated according to surgical positioning (supine or prone) during routine perioperative care.
Who may be able to join
- Adult patients aged 18 years or older.
- Patients scheduled for elective surgery under general anesthesia.
- Patients undergoing surgery in the supine or prone position.
- Patients able to provide informed consent.
Who cannot join
- Emergency surgical procedures.
- Pre-existing severe pulmonary disease affecting lung ultrasound assessment.
- Hemodynamic instability requiring urgent intervention.
- Contraindications to lung ultrasound examination.
Trial locations and contacts
1 site in 1 country.
Turkey (Türkiye)1 site
Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine
Istanbul, Istanbul, 34320
About this study
Official title: Comparison of the Incidence of Atelectasis Assessed by Lung Ultrasound in Patients Undergoing Surgery in Supine and Prone Positions
Atelectasis frequently develops during and after general anesthesia due to factors such as anesthesia-induced diaphragmatic dysfunction, reduced functional residual capacity, altered ventilation-perfusion matching, and surgical positioning. The development of atelectasis has been associated with postoperative hypoxemia and other pulmonary complications.
Lung ultrasound (LUS) has emerged as a reliable, radiation-free bedside imaging modality for the detection and monitoring of atelectasis. LUS allows assessment of lung aeration through standardized ultrasound patterns and scoring systems, enabling dynamic evaluation in the perioperative period.
Read more
This is a prospective, observational cohort study designed to compare the incidence and severity of atelectasis in patients undergoing surgery in the supine position versus the prone position under general anesthesia. Adult patients undergoing elective surgical procedures will be enrolled. No experimental intervention will be applied, and all anesthetic and surgical management will follow routine clinical practice.
Lung ultrasound examinations will be performed at predefined time points after induction of anesthesia and before extubation. A standardized lung ultrasound protocol and scoring system will be used to assess lung aeration loss and detect the presence of atelectasis.
The primary outcome of the study is the difference in atelectasis detected by lung ultrasound between supine and prone surgical positions. The secondary outcome is the change in lung ultrasound scores over time.
This study aims to clarify the effects of supine and prone positions on perioperative atelectasis and to support the clinical use of lung ultrasound as a noninvasive monitoring tool in perioperative and anesthetic practice..
- Conditions
- Postoperative Atelectasis
- Keywords
- Lung Ultrasound, Atelectasis, Supine Position, Prone Position, General Anesthesia, Perioperative Care
- Medical subject headings
- Pulmonary Atelectasis, Deception
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Supine Position | Patients undergoing surgery in the supine position under general anesthesia. | |
| Prone Position | Patients undergoing surgery in the prone position under general anesthesia. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Difference in lung ultrasound-detected atelectasis between supine and prone surgical positions
Lung aeration will be evaluated using the Lung Ultrasound Score (LUS), a semiquantitative scoring system assessing aeration loss in 12 lung regions.
In the supine position, lung ultrasound assessment will be performed along:
the parasternal line (intercostal spaces 1-4 and 4-8), the anterior axillary line (intercostal spaces 1-6 and 6-12), and the posterior axillary line (intercostal spaces 1-6 and 6-12).
In the prone position, lung ultrasound assessment will be performed along:
the paravertebral line (intercostal spaces 1-6 and 6-12), the posterior axillary line (intercostal spaces 1-6 and 6-12), and the anterior axillary line (intercostal spaces 1-6 and 6-12). Each lung region will be scored from 0 to 3, resulting in a total LUS ranging from 0 to 36, where higher scores indicate greater loss of aeration and more severe atelectasis.
Assessments will be performed after induction of general anesthesia and before extubation.
Measured: Perioperative (After induction of general anesthesia and before extubation)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Jan 2026
- Study start15 Sep 2025
- Primary completion30 Mar 2026
- Study completion15 Apr 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (5)Papers the sponsor has linked to this study.
- Other trials for Postoperative AtelectasisStudies of the same condition, open and under way.
- More trials run by Istanbul University - CerrahpasaThe 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
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 80 participants (actual)
Sponsor and investigators
- Lead sponsor
- Istanbul University - Cerrahpasa
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, CHINARA NAMAZOVA, Istanbul University - Cerrahpasa
- Investigators
- ÖZLEM KORKMAZ DİLMEN, PROFESSOR, Principal investigator, Istanbul University - Cerrahpasa
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07320092
- Sponsor's protocol ID
- E-74555795-050.04-1231752
- Other IDs
- 2025/24
- Acronym
- LUS-ATELEC
- Status last verified
- Mar 2026
- First submitted
- 22 Dec 2025
- Last updated
- 6 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared, as this is a single-center observational study conducted for a postgraduate thesis.
Publications
Bouhemad B, Brisson H, Le-Guen M, Arbelot C, Lu Q, Rouby JJ. Bedside ultrasound assessment of positive end-expiratory pressure-induced lung recruitment. Am J Respir Crit Care Med. 2011 Feb 1;183(3):341-7. doi: 10.1164/rccm.201003-0369OC. Epub 2010 Sep 17.
PubMed 20851923Tusman G, Böhm SH, Warner DO, Sprung J. Atelectasis and perioperative pulmonary complications in general anesthesia. Br J Anaesth. 2012;108(2):229-240. PMID: 22156255.
Acosta CM, Maidana GA, Jacovitti D, Belaunzaran A, Cereceda S, Rae E, Molina A, Gonorazky S, Bohm SH, Tusman G. Accuracy of transthoracic lung ultrasound for diagnosing anesthesia-induced atelectasis in children. Anesthesiology. 2014 Jun;120(6):1370-9. doi: 10.1097/ALN.0000000000000231.
PubMed 24662376Monastesse A, Girard F, Massicotte N, Chartrand-Lefebvre C, Girard M. Lung Ultrasonography for the Assessment of Perioperative Atelectasis: A Pilot Feasibility Study. Anesth Analg. 2017 Feb;124(2):494-504. doi: 10.1213/ANE.0000000000001603.
PubMed 27669555Lichtenstein DA. Lung ultrasound in the critically ill. Ann Intensive Care. 2014 Jan 9;4(1):1. doi: 10.1186/2110-5820-4-1.
PubMed 24401163
Study at a glance
From the registry record, last updated by the sponsor on 6 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Comparison of the Incidence of Atelectasis Assessed by Lung Ultrasound in Patients Undergoing Surgery in Supine and Prone Positions
- ClinicalTrials.gov ID
- NCT07320092
- Acronym / sponsor ID
- LUS-ATELEC / E-74555795-050.04-1231752
- Conditions
- Postoperative Atelectasis
- Keywords
- Lung Ultrasound, Atelectasis, Supine Position, Prone Position, General Anesthesia, Perioperative Care
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 80 participants (actual)
- Lead sponsor
- Istanbul University - CerrahpasaUniversity, hospital or other
- Study start
- 15 Sep 2025 (actual)
- Primary completion
- 30 Mar 2026 (actual)
- Study completion
- 15 Apr 2026 (actual)
- First posted
- 6 Jan 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.
Atelectasis frequently develops during and after general anesthesia due to factors such as anesthesia-induced diaphragmatic dysfunction, reduced functional residual capacity, altered ventilation-perfusion matching, and surgical positioning. The development of atelectasis has been associated with postoperative hypoxemia and other pulmonary complications.
Lung ultrasound (LUS) has emerged as a reliable, radiation-free bedside imaging modality for the detection and monitoring of atelectasis. LUS allows assessment of lung aeration through standardized ultrasound patterns and scoring systems, enabling dynamic evaluation in the perioperative period.
This is a prospective, observational cohort study designed to compare the incidence and severity of atelectasis in patients undergoing surgery in the supine position versus the prone position under general anesthesia. Adult patients undergoing elective surgical procedures will be enrolled. No experimental intervention will be applied, and all anesthetic and surgical management will follow routine clinical practice.
Lung ultrasound examinations will be performed at predefined time points after induction of anesthesia and before extubation. A standardized lung ultrasound protocol and scoring system will be used to assess lung aeration loss and detect the presence of atelectasis.
The primary outcome of the study is the difference in atelectasis detected by lung ultrasound between supine and prone surgical positions. The secondary outcome is the change in lung ultrasound scores over time.
This study aims to clarify the effects of supine and prone positions on perioperative atelectasis and to support the clinical use of lung ultrasound as a noninvasive monitoring tool in perioperative and anesthetic practice..
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Supine Position | – | –Patients undergoing surgery in the supine position under general anesthesia. |
| Prone Position | – | –Patients undergoing surgery in the prone position under general anesthesia. |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- The study population consists of adult patients aged 18 years and older who are scheduled to undergo elective surgical procedures under general anesthesia. Patients will be evaluated according to surgical positioning (supine or prone) during routine perioperative care.
Key inclusion criteria (4 listed)
- Adult patients aged 18 years or older.
- Patients scheduled for elective surgery under general anesthesia.
- Patients undergoing surgery in the supine or prone position.
- Patients able to provide informed consent.
Key exclusion criteria (4 listed)
- Emergency surgical procedures.
- Pre-existing severe pulmonary disease affecting lung ultrasound assessment.
- Hemodynamic instability requiring urgent intervention.
- Contraindications to lung ultrasound examination.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Difference in lung ultrasound-detected atelectasis between supine and prone surgical positions
Time frame: Perioperative (After induction of general anesthesia and before extubation)
Lung aeration will be evaluated using the Lung Ultrasound Score (LUS), a semiquantitative scoring system assessing aeration loss in 12 lung regions. In the supine position, lung ultrasound assessment will be performed along: the parasternal line (intercostal spaces 1-4 and 4-8), the anterior axillary line (intercostal spaces 1-6 and 6-12), and the posterior axillary line (intercostal spaces 1-6 and 6-12). In the prone position, lung ultrasound assessment will be performed along: the paravertebral line (intercostal spaces 1-6 and 6-12), the posterior axillary line (intercostal spaces 1-6 and 6-12), and the anterior axillary line (intercostal spaces 1-6 and 6-12). Each lung region will be scored from 0 to 3, resulting in a total LUS ranging from 0 to 36, where higher scores indicate greater loss of aeration and more severe atelectasis. Assessments will be performed after induction of general anesthesia and before extubation.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Jul 2026.
- Background: PubMed 20851923Bouhemad B, Brisson H, Le-Guen M, Arbelot C, Lu Q, Rouby JJ. Bedside ultrasound assessment of positive end-expiratory pressure-induced lung recruitment. Am J Respir Crit Care Med. 2011 Feb 1;183(3):341-7. doi: 10.1164/rccm.201003-0369OC. Epub 2010 Sep 17.
- BackgroundTusman G, Böhm SH, Warner DO, Sprung J. Atelectasis and perioperative pulmonary complications in general anesthesia. Br J Anaesth. 2012;108(2):229-240. PMID: 22156255.
- Background: PubMed 24662376Acosta CM, Maidana GA, Jacovitti D, Belaunzaran A, Cereceda S, Rae E, Molina A, Gonorazky S, Bohm SH, Tusman G. Accuracy of transthoracic lung ultrasound for diagnosing anesthesia-induced atelectasis in children. Anesthesiology. 2014 Jun;120(6):1370-9. doi: 10.1097/ALN.0000000000000231.
- Background: PubMed 27669555Monastesse A, Girard F, Massicotte N, Chartrand-Lefebvre C, Girard M. Lung Ultrasonography for the Assessment of Perioperative Atelectasis: A Pilot Feasibility Study. Anesth Analg. 2017 Feb;124(2):494-504. doi: 10.1213/ANE.0000000000001603.
- Background: PubMed 24401163Lichtenstein DA. Lung ultrasound in the critically ill. Ann Intensive Care. 2014 Jan 9;4(1):1. doi: 10.1186/2110-5820-4-1.
- Individual participant dataSharing planned: No. Individual participant data will not be shared, as this is a single-center observational study conducted for a postgraduate thesis.
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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. This study is not recruiting at the moment.
ÖZLEM KORKMAZ DİLMEN, PROFESSOR principal investigator
Istanbul University - Cerrahpasa
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Postoperative Atelectasis, run by Istanbul University - Cerrahpasa 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 4 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: finished, as of the sponsor's last update on 6 Jul 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Difference in lung ultrasound-detected atelectasis between supine and prone surgical positions (time frame: Perioperative (After induction of general anesthesia and before extubation)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07320092, which also lists 5 linked publications.
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 6 Jul 2026.