Postoperative SpO₂/FiO₂ Ratio and Analgesic Methods in Laparoscopic Surgery

February 3, 2026 updated by: İlke Dolgun, Istinye University

Association of Postoperative SpO₂/FiO₂ Ratio With Body Mass Index, STOP-BANG Score, and Analgesic Methods in Patients Undergoing Laparoscopic Surgery in Reverse Trendelenburg Position

This prospective observational study aims to evaluate the association between postoperative oxygenation, assessed by the SpO₂/FiO₂ ratio, and body mass index (BMI), STOP-BANG score, and postoperative analgesic methods in patients undergoing elective laparoscopic cholecystectomy in the reverse Trendelenburg position. Postoperative SpO₂ and FiO₂ values will be recorded within the first postoperative hour, and the SpO₂/FiO₂ ratio will be calculated. Analgesic techniques applied as part of routine clinical practice will be documented. The study does not involve any additional intervention beyond standard care. The findings are expected to contribute to a better understanding of factors associated with early postoperative oxygenation and hypoxemia risk.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
100

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Turkey (Türkiye)
    • Merkez Mahallesi
      • Istanbul, Merkez Mahallesi, Turkey (Türkiye), 34250
        • Istinye University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

The study population consists of adult patients aged 18 years and older with ASA physical status I-III who undergo elective laparoscopic cholecystectomy in the reverse Trendelenburg position. All participants provide written informed consent. Patients with significant respiratory or cardiovascular comorbidities, emergency surgery, or perioperative respiratory complications are excluded.

Description

Inclusion Criteria:

  • Age ≥ 18 years
  • Patients who provide written informed consent
  • ASA physical status I-III
  • Patients undergoing elective laparoscopic cholecystectomy
  • Surgery performed in the reverse Trendelenburg position (30°)
  • Expected operative duration < 3 hours
  • Exclusion Criteria:
  • Age < 18 years
  • Refusal or inability to provide informed consent
  • ASA physical status IV or higher
  • Known chronic respiratory diseases (e.g., asthma, COPD)
  • Severe cardiac failure (NYHA class III-IV) or advanced cardiovascular disease
  • Emergency surgery
  • Preoperative oxygen supplementation or baseline SpO₂ < 90%
  • Prolonged intubation or perioperative respiratory complications
  • Requirement for postoperative noninvasive ventilation or intensive care unit admission
  • Missing SpO₂ or FiO₂ data preventing calculation of the SpO₂/FiO₂ ratio

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
control
Other: Standard of Care
No intervention is applied in this study. Patients are managed according to routine clinical practice. Demographic data, body mass index, STOP-BANG score, postoperative analgesic methods, and postoperative SpO₂ and FiO₂ values are recorded, and the SpO₂/FiO₂ ratio is calculated. All data are collected observationally without any additional procedures or changes to standard care.
Postoperative Observational Cohort
Other: Standard of Care
No intervention is applied in this study. Patients are managed according to routine clinical practice. Demographic data, body mass index, STOP-BANG score, postoperative analgesic methods, and postoperative SpO₂ and FiO₂ values are recorded, and the SpO₂/FiO₂ ratio is calculated. All data are collected observationally without any additional procedures or changes to standard care.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
postoperative SpO₂/FiO₂ Ratio
Time Frame: Within the first postoperative hour (0-60 minutes after surgery)
The SpO₂/FiO₂ ratio calculated using peripheral oxygen saturation (SpO₂) and fraction of inspired oxygen (FiO₂) measured during the early postoperative period to assess postoperative oxygenation.
Within the first postoperative hour (0-60 minutes after surgery)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Istinye University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
February 15, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 15, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 31, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 3, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 3, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 10, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 10, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 3, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 293-2025

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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