Year: 2025
Type: article
Study designs: Randomized Controlled Trial, Clinical Trial
Abstract: Background: The Oxygen Reserve Index (ORI) is a real-time monitoring measure associated with oxygen reserve status in the moderate hyperoxic range (arterial oxygen tensionapproximately 100-200 mmHg).In this study, our primary objective was to determine whether ORI can be a reliable and sensitive indicator of hypoxia in minimalflow anesthesia (MFA) settings.Methods: This randomized controlled trial included 64 patients who were randomized into two groups: Group M (minimal flow anesthesia group) and Group H (high flow anesthesia group).The subjects were American Society of Anesthesiologists (ASA) I-III patients aged 18-75 who underwent elective ear, nose and throat surgery lasting longer than 60 min under general anesthesia.In Group H, a fresh gas flow (FGF) of 4 L/min was used, while in Group M, a FGF of 0.5 L/min was administered.ORI monitoring was performed on all patients.Results: Both groups were comparable in terms of height, weight, ASA classification, surgery and anesthesia durations, preoperative hemoglobin and the saturation of peripheral oxygen (SpO 2 ) and basal ORI levels.ORI values were similar between the groups during preoxygenation, after intubation, and at 5 min post-intubation.Statistically significant differences favoring in favor of Group M were observed at 10 min, 15 min, 20 min and 35 min.End-tidal O 2 values at intubation and 5 min post-intubation were similar; however, significant differences were found at 10, 15, 20 and 35 min post-intubation, and after increasing fresh gas flow.Conclusions: The ORI values can help detect impending desaturation before changes in SpO 2 are evident.Our findings suggest that ORI monitoring during low-flow anesthesia application can be valuable in avoiding hypoxia, thereby supporting the application of low-flow anesthesia techniques.Clinical Trial Registration: Clinical trials ID: NCT06649279.
Source: Signa Vitae
DOI: 10.22514/sv.2025.084
Authors: Fatih Sahin, Yakup Uzun, Burak Kaya, Havva Kocayigit, Ali Fuat Erdem
Institutions: Sakarya University, Sakarya Eğitim ve Araştırma Hastanesi
Language: English
Subfield: Anesthesiology and Pain Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W4411101997