The Use of Oxygen Reserve Index in One-Lung Ventilation and Its Impact On Peripheral Oxygen Saturation, Perfusion Index and Pleth Variability Index

Abstract

Background: Our goal is to investigate the use of the Oxygen Reserve Index (ORi) and its relation with peripheral oxygen saturation, perfusion index (PI), and pleth variability index (PVI) during one-lung ventilation (OLV).Methods: Fifty patients undergoing general anesthesia and OLV for elective thoracic surgeries were enrolled in an observational cohort study in a tertiary care teaching hospital. During general anesthesia induction, propofol, fentanyl, and rocuronium at appropriate doses were administered intravenously. All patients required OLV after a left-sided double-lumen tube insertion during intubation. Hypoxemia during OLV was defined as peripheral oxygen saturation (SpO2) value of less than 95% when the inspired oxygen fraction (FiO2) is above 60% on a pulse oximetry device. ORi, pulse oximetry, PI, and PVI were measured continuously. Sensitivity, specificity, positive and negative predictive values, likelihood ratios, and accuracy were calculated for ORi equals zero in different anesthesia time points to predict hypoxemia. At Clinicaltrials.gov registry, the Registration ID is NCT05050552.Results: The accuracy for predicting hypoxemia during anesthesia induction at ORi value equals zero at five minutes after intubation in the supine position (DS5) showed a sensitivity of 92.3% (95% CI 84.9-99.6), specificity of 81.1% (95% CI 70.2-91.9), and an accuracy of 84.0% (95% CI 73.8- 94.2). ORi and SpO2 correlation was found at DS5 (p = 0.044), 5 minutes after lateral position with two-lung ventilation (DL5) (p = 0.039), and at 10 minutes after OLV (OLV10)(p = 0.011).Conclusions: ORi equals zero at the time point of five minutes after tracheal intubation in the supine position (DS5) showed high sensitivity and specificity for predicting hypoxemia at a less than 95% value.