AtelectasisNCT07050719
Can Atelectasis Be Prevented With Oxygen Reserve Index (ORI) Monitoring?
A study testing Peripheral Oxygen Saturation (SpO₂) Group and Peripheral Oxygen Saturation and Oxygen Reserve Index (SpO₂-ORI) Group in people with Atelectasis and Lung Ultrasonography Score, run by Antalya Training and Research Hospital at 1 site in Turkey (Türkiye).
Trial summary
This single-center randomized controlled trial aims to evaluate whether intraoperative monitoring using the Oxygen Reserve Index (ORI) reduces the incidence of postoperative atelectasis, as assessed by lung ultrasound (LUS), in adult patients undergoing elective robotic surgery under general anesthesia. Read more about this study
- Who is it for?
- Ages 18 to 75 years
- Conditions the study is for
- Atelectasis, Lung Ultrasonography Score, Hyperoxia
- What is being tested?
- Peripheral Oxygen Saturation (SpO₂) Group and Peripheral Oxygen Saturation and Oxygen Reserve Index (SpO₂-ORI) Group
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 58 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 15 Jul 2025to 8 Dec 2025
- Phase
- Interventional
- 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 75 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- American Society of Anesthesiologists Physical Status Classification System (ASA) physical status I-III
- Elective robotic surgery under general anesthesia
- Surgery duration >2 hours
- Requires invasive arterial cannulation
- Signed informed consent
Who cannot join
- ASA IV or higher
- Room air SpO₂ <92%
- Chronic pulmonary disease
- Hemoglobinopathy
- Pregnancy
- Refusal to participate
Trial locations and contacts
1 site in 1 country.
Turkey (Türkiye)1 site
Antalya Training and Research Hospital
Antalya, Muratpasa, 07100
About this study
Official title: Can Atelectasis be Prevented in Robotic Surgery by Monitoring With Oxygen Reserve Index (ORI)? A Randomized Controlled Trial
This single-center randomized controlled trial aims to evaluate whether intraoperative monitoring using the Oxygen Reserve Index (ORI) reduces the incidence of postoperative atelectasis, as assessed by lung ultrasound (LUS), in adult patients undergoing elective robotic surgery under general anesthesia.
Read the detailed description
Postoperative atelectasis is observed in 60-90% of patients undergoing general anesthesia. Factors such as high inspired oxygen concentration, muscle relaxation, and reduced functional residual capacity contribute to its development through mechanisms like absorption atelectasis. The persistence of atelectasis increases the risk of pneumonia, hypoxia, prolonged hospital stay, healthcare costs, and mortality. Despite the well-known pathophysiology, the optimal intraoperative fraction of inspired oxygen (FiO₂) remains unclear.
The Oxygen Reserve Index (ORI) is a non-invasive, continuous parameter that reflects the oxygen reserve within the moderate hyperoxia range (100-200 mmHg). It may facilitate individualized FiO₂ titration to avoid hyperoxia-related atelectasis. Lung ultrasound (LUS) is a reliable, radiation-free bedside tool for detecting atelectasis.
This study hypothesizes that ORI-guided oxygen therapy will reduce the incidence of postoperative atelectasis compared to standard Peripheral Capillary Oxygen Saturation (SpO₂)-guided therapy.
- Conditions
- Atelectasis, Lung Ultrasonography Score, Hyperoxia
- Being tested
- Peripheral Oxygen Saturation (SpO₂) Group, Peripheral Oxygen Saturation and Oxygen Reserve Index (SpO₂-ORI) Group
- Keywords
- Atelectasis, ORI, robotic surgery, lung ultrasound score, hyperoxia
- Medical subject headings
- Pulmonary Atelectasis, Hyperoxia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Peripheral Oxygen Saturation (SpO₂) GroupProcedure or surgery
FiO₂ adjusted based on pulse oximetry to maintain SpO₂ ≥98%
Peripheral Oxygen Saturation and Oxygen Reserve Index (SpO₂-ORI) GroupProcedure or surgery
FiO₂ adjusted using both SpO₂ and ORI to maintain ORI between 0-0.3
| Study group | Role | What they receive |
|---|---|---|
| Peripheral Oxygen Saturation (SpO₂) Group | Active comparator | FiO₂ adjusted based on pulse oximetry to maintain SpO₂ ≥98% Receives: Procedure: Peripheral Oxygen Saturation (SpO₂) Group |
| Peripheral Oxygen Saturation and Oxygen Reserve Index (SpO₂-ORI) Group | Active comparator | FiO₂ adjusted using both SpO₂ and ORI to maintain ORI between 0-0.3 Receives: Procedure: Peripheral Oxygen Saturation and Oxygen Reserve Index (SpO₂-ORI) Group |
What is being measured
The primary outcome is the main question the study is designed to answer.
Postoperative LUS score at 30 min
Lung ultrasound (LUS) measurements will be performed by an anesthesiologist blinded to the study groups, who is experienced in lung ultrasonography with at least 100 prior examinations. LUS will be performed and recorded 30 minutes before surgery while patients are in the supine position, using a linear probe (6-12 MHz). The total LUS score will be calculated as the sum of the scores for the 12 quadrants of each hemithorax (range: 0-36). Higher scores will indicate more severe loss of aeration. Loss of aeration will be scored as follows:
- 0: Presence of A-lines or fewer than two B-lines
- 1: Three or more well-defined B-lines
- 2: Presence of multiple coalescent B-lines
- 3: Presence of lung consolidation characterized by dynamic air bronchograms
Measured: At 30 minutes following tracheal extubation at the end of surgery
Secondary outcomes (5)
Preoperative LUS score
Lung ultrasound (LUS) measurements will be performed by an anesthesiologist blinded to the study groups, who is experienced in lung ultrasonography with at least 100 prior examinations. LUS will be performed and recorded 30 minutes before surgery while patients are in the supine position, using a linear probe (6-12 MHz). The total LUS score will be calculated as the sum of the scores for the 12 quadrants of each hemithorax (range: 0-36). Higher scores will indicate more severe loss of aeration. Loss of aeration will be scored as follows: • 0: Presence of A-lines or fewer than two B-lines • 1: Three or more well-defined B-lines • 2: Presence of multiple coalescent B-lines • 3: Presence of lung consolidation characterized by dynamic air bronchograms
Measured: 30 minutes prior to patient transfer to the operating room
Intraoperative arterial partial pressure of oxygen (PaO₂)
Arterial blood samples will be collected intraoperatively at baseline (immediately before skin incision) and at the 1st, 2nd, and 3rd hour to measure the partial pressure of oxygen (PaO₂).
Measured: At baseline (immediately before incision), and at 1st, 2nd, and 3rd hour intraoperatively
Intraoperative fraction of inspired oxygen (FiO₂)
The fraction of inspired oxygen administered to the patient will be recorded at baseline (immediately before skin incision) and hourly at the 1st, 2nd, and 3rd hour during surgery.
Measured: At baseline (immediately before incision), and at 1st, 2nd, and 3rd hour intraoperatively
Intraoperative Oxygen Reserve Index (ORI)
Continuous monitoring of the Oxygen Reserve Index (ORI) will be performed, and values will be documented at baseline (immediately before skin incision) and at 1st, 2nd, and 3rd hour intraoperatively.Intraoperative Oxygen Reserve Index (ORI) will be measured. ORI is a unitless index ranging from 0.00 to 1.00, with higher values indicating a greater oxygen reserve.
Measured: At baseline (immediately before incision), and at 1st, 2nd, and 3rd hour intraoperatively
Number of episodes with severe hyperoxia (PaO₂ > 200 mmHg)
The number of severe hyperoxia episodes, defined as PaO₂ levels exceeding 200 mmHg, will be recorded at baseline (immediately before skin incision) and at the 1st, 2nd, and 3rd hour during surgery.Each time point will be evaluated independently, and the number of measurements exceeding 200 mmHg will be counted.This is a binary threshold-based event count, not a continuous scale; thus, no scoring system or scale interpretation is applicable.
Measured: At baseline (immediately before incision), and at 1st, 2nd, and 3rd hour intraoperatively
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Jul 2025
- Study start15 Jul 2025
- Primary completion8 Dec 2025
- Study completion8 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for 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
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 58 participants (actual)
Sponsor and investigators
- Lead sponsor
- Antalya Training and Research Hospital
- Sponsor type
- Other government
- Responsible party
- Principal investigator, Nilgun Kavrut Ozturk, Antalya Training and Research Hospital
- Investigators
- NILGUN KAVRUT OZTURK, PROFESSOR MD, Study chair, Antalya Training and Research HospitalAYSE MERVE ERDEM, RESIDENT, Principal investigator, Antalya Training and Research Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07050719
- Sponsor's protocol ID
- AEAHAE001
- Status last verified
- Dec 2025
- First submitted
- 22 Jun 2025
- Last updated
- 10 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 10 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Can Atelectasis be Prevented in Robotic Surgery by Monitoring With Oxygen Reserve Index (ORI)? A Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT07050719
- Acronym / sponsor ID
- AEAHAE001
- Conditions
- Atelectasis, Lung Ultrasonography Score, Hyperoxia
- Keywords
- Atelectasis, ORI, robotic surgery, lung ultrasound score, hyperoxia
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 58 participants (actual)
- Lead sponsor
- Antalya Training and Research HospitalOther government
- Study start
- 15 Jul 2025 (actual)
- Primary completion
- 8 Dec 2025 (actual)
- Study completion
- 8 Dec 2025 (actual)
- First posted
- 3 Jul 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 single-center randomized controlled trial aims to evaluate whether intraoperative monitoring using the Oxygen Reserve Index (ORI) reduces the incidence of postoperative atelectasis, as assessed by lung ultrasound (LUS), in adult patients undergoing elective robotic surgery under general anesthesia.
Detailed description
Postoperative atelectasis is observed in 60-90% of patients undergoing general anesthesia. Factors such as high inspired oxygen concentration, muscle relaxation, and reduced functional residual capacity contribute to its development through mechanisms like absorption atelectasis. The persistence of atelectasis increases the risk of pneumonia, hypoxia, prolonged hospital stay, healthcare costs, and mortality. Despite the well-known pathophysiology, the optimal intraoperative fraction of inspired oxygen (FiO₂) remains unclear.
The Oxygen Reserve Index (ORI) is a non-invasive, continuous parameter that reflects the oxygen reserve within the moderate hyperoxia range (100-200 mmHg). It may facilitate individualized FiO₂ titration to avoid hyperoxia-related atelectasis. Lung ultrasound (LUS) is a reliable, radiation-free bedside tool for detecting atelectasis.
This study hypothesizes that ORI-guided oxygen therapy will reduce the incidence of postoperative atelectasis compared to standard Peripheral Capillary Oxygen Saturation (SpO₂)-guided therapy.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Peripheral Oxygen Saturation (SpO₂) Group | Active comparator | Procedure: Peripheral Oxygen Saturation (SpO₂) GroupFiO₂ adjusted based on pulse oximetry to maintain SpO₂ ≥98% |
| Peripheral Oxygen Saturation and Oxygen Reserve Index (SpO₂-ORI) Group | Active comparator | Procedure: Peripheral Oxygen Saturation and Oxygen Reserve Index (SpO₂-ORI) GroupFiO₂ adjusted using both SpO₂ and ORI to maintain ORI between 0-0.3 |
Who may qualify
- Ages
- 18 to 75 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- American Society of Anesthesiologists Physical Status Classification System (ASA) physical status I-III
- Elective robotic surgery under general anesthesia
- Surgery duration >2 hours
- Requires invasive arterial cannulation
- Signed informed consent
Key exclusion criteria (6 listed)
- ASA IV or higher
- Room air SpO₂ <92%
- Chronic pulmonary disease
- Hemoglobinopathy
- Pregnancy
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 |
|---|---|---|
| Peripheral Oxygen Saturation (SpO₂) GroupFiO₂ adjusted based on pulse oximetry to maintain SpO₂ ≥98% | Procedure or surgery | Peripheral Oxygen Saturation (SpO₂) Group |
| Peripheral Oxygen Saturation and Oxygen Reserve Index (SpO₂-ORI) GroupFiO₂ adjusted using both SpO₂ and ORI to maintain ORI between 0-0.3 | Procedure or surgery | Peripheral Oxygen Saturation and Oxygen Reserve Index (SpO₂-ORI) Group |
Primary outcome
Postoperative LUS score at 30 min
Time frame: At 30 minutes following tracheal extubation at the end of surgery
Lung ultrasound (LUS) measurements will be performed by an anesthesiologist blinded to the study groups, who is experienced in lung ultrasonography with at least 100 prior examinations. LUS will be performed and recorded 30 minutes before surgery while patients are in the supine position, using a linear probe (6-12 MHz). The total LUS score will be calculated as the sum of the scores for the 12 quadrants of each hemithorax (range: 0-36). Higher scores will indicate more severe loss of aeration. Loss of aeration will be scored as follows: * 0: Presence of A-lines or fewer than two B-lines * 1: Three or more well-defined B-lines * 2: Presence of multiple coalescent B-lines * 3: Presence of lung consolidation characterized by dynamic air bronchograms
5 secondary outcomes
Preoperative LUS score
Time frame: 30 minutes prior to patient transfer to the operating room
Intraoperative arterial partial pressure of oxygen (PaO₂)
Time frame: At baseline (immediately before incision), and at 1st, 2nd, and 3rd hour intraoperatively
Intraoperative fraction of inspired oxygen (FiO₂)
Time frame: At baseline (immediately before incision), and at 1st, 2nd, and 3rd hour intraoperatively
Intraoperative Oxygen Reserve Index (ORI)
Time frame: At baseline (immediately before incision), and at 1st, 2nd, and 3rd hour intraoperatively
Number of episodes with severe hyperoxia (PaO₂ > 200 mmHg)
Time frame: At baseline (immediately before incision), and at 1st, 2nd, and 3rd hour intraoperatively
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 10 Dec 2025.
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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.
NILGUN KAVRUT OZTURK, PROFESSOR MD study chair
Antalya Training and Research Hospital
AYSE MERVE ERDEM, RESIDENT principal investigator
Antalya Training and Research Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Peripheral Oxygen Saturation (SpO₂) Group and Peripheral Oxygen Saturation and Oxygen Reserve Index (SpO₂-ORI) Group in people with Atelectasis and Lung Ultrasonography Score, run by Antalya Training and Research Hospital 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 5 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: finished, as of the sponsor's last update on 10 Dec 2025. 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?
Postoperative LUS score at 30 min (time frame: At 30 minutes following tracheal extubation at the end of surgery). 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 10 Dec 2025.