Postoperative SpO₂/FiO₂ Ratio and Analgesic Methods in Laparoscopic Surgery

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: Not yet recruiting
• Conditions: Postoperative Hypoxemia
• Intervention / Treatment: Other: Standard of Care

• Study Type: Observational
• Enrollment (Estimated): 100

Contacts and Locations

• Study Contact: Name: ilke dolgun; Phone Number: +905555485632; Email: ilkeser2004@gmail.com

Study Locations

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

Participation Criteria

Eligibility Criteria

• 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

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
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

Outcome Measure	Measure Description	Time Frame
postoperative SpO₂/FiO₂ Ratio	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

• Sponsor: Istinye University

Publications and helpful links

General Publications

• Perilli V, Sollazzi L, Bozza P, Modesti C, Chierichini A, Tacchino RM, Ranieri R. The effects of the reverse trendelenburg position on respiratory mechanics and blood gases in morbidly obese patients during bariatric surgery. Anesth Analg. 2000 Dec;91(6):1520-5. doi: 10.1097/00000539-200012000-00041.
• Aboseif A, Bedewy A, Nafei M, Hammad R, Amin S. Effect of Intraoperative Lung Recruitment and Transversus Abdominis Plane Block in Laparoscopic Bariatric Surgery on Postoperative Lung Functions: A Randomized Controlled Study. Anesth Pain Med. 2023 Mar 5;13(2):e128440. doi: 10.5812/aapm-128440. eCollection 2023 Apr.

Study record dates

Study Major Dates

• Study Start (Estimated): February 15, 2026
• Primary Completion (Estimated): March 15, 2026
• Study Completion (Estimated): March 31, 2026

Study Registration Dates

• First Submitted: February 3, 2026
• First Submitted That Met QC Criteria: February 3, 2026
• First Posted (Actual): February 10, 2026

Study Record Updates

• Last Update Posted (Actual): February 10, 2026
• Last Update Submitted That Met QC Criteria: February 3, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Health Services Administration; Health Care Quality, Access, and Evaluation; Quality of Health Care; Quality Indicators, Health Care; Standard of Care
• Other Study ID 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