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Oxygen Reserve Index in Laparoscopic Colorectal Surgery

NCT07445698 · Status: COMPLETED · Type: OBSERVATIONAL · Enrollment: 60

Last updated 2026-03-03

No results posted yet for this study

Summary

During laparoscopic procedures, certain physiological changes occur due to the creation of pneumoperitoneum. One such change is the reduction in portal venous blood flow, which can lead to decreased liver perfusion and acute liver cell injury. Additionally, due to an increased alveolar-arterial oxygen pressure gradient, postoperative atelectasis may occur, leading to hypoxia.

In other words, the increased intra-abdominal pressure during laparoscopic surgery-along with the effects of patient positioning and mechanical ventilation used during anesthesia-can worsen low blood oxygen levels, especially in patients with already reduced lung compliance and higher metabolic demands. This makes close monitoring of oxygenation crucial.

The Oxygen Reserve Index (ORI) is a relatively new tool that can help monitor both high oxygen levels (hyperoxemia) and drops in oxygen (desaturation) before they become clinically apparent. Studies have shown that ORI values range from 0 to 1, with an ORI of 0 typically corresponding to a PaO₂ level between 80-125 mmHg. A downward trend in ORI can act as an early warning sign of hypoxemia, giving clinicians a chance to act before it's too late.

Many studies have highlighted the potential harms of using high oxygen concentrations during surgery. For example, while most hospitals still give patients 100% oxygen before anesthesia (a process called preoxygenation), recent evidence suggests this might increase the risk of atelectasis. Therefore, using 80% or less oxygen is now being recommended in many settings. High oxygen levels have also been linked to increased oxidative stress in the body.

In this study, we aim to investigate whether monitoring ORI during extubation can help us detect and prevent both hyperoxemia and hypoxemia-situations that standard pulse oximetry often misses. We plan to compare two groups of patients: one receiving conventional 100% oxygen during extubation, and another receiving 80% oxygen. By monitoring ORI values in both groups, we hope to better understand how different oxygen levels affect patient safety and outcomes.

Conditions

  • Laparoscopic Colorectal Surgery

Interventions

BEHAVIORAL

Oxygen Administration During Extubation

This intervention involves the administration of oxygen during tracheal extubation in patients undergoing laparoscopic surgery. Two different oxygen concentrations are compared: the control group receives 100% oxygen, while the study group receives 80% oxygen during the extubation phase. All patients are monitored using the Oxygen Reserve Index (ORI) to assess oxygenation status continuously. The goal is to evaluate the effect of oxygen concentration on peri-extubation hyperoxia and hypoxia, as detected by ORI values. The intervention is non-invasive and administered via standard anesthesia breathing systems.

Sponsors & Collaborators

  • Dr. Lutfi Kirdar Kartal Training and Research Hospital

    lead OTHER_GOV

Eligibility

Min Age
18 Years
Max Age
75 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2025-01-07
Primary Completion
2025-12-30
Completion
2026-02-10

Countries

  • Turkey (Türkiye)

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT07445698 on ClinicalTrials.gov