The use of oxygen reserve index in one-lung ventilation and its impact on peripheral oxygen saturation, perfusion index and, pleth variability index.

Our goal is to investigate the use of the oxygen reserve index (ORi) to detect hypoxemia and its relation with parameters such as; peripheral oxygen saturation, perfusion index (PI), and pleth variability index (PVI) during one-lung ventilation (OLV). Fifty patients undergoing general anesthesia and OLV for elective thoracic surgeries were enrolled in an observational cohort study in a tertiary care teaching hospital. All patients required OLV after a left-sided double-lumen tube insertion during intubation. The definition of hypoxemia during OLV is a peripheral oxygen saturation (SpO2) value of less than 95%, while the inspired oxygen fraction (FiO2) is higher than 50% on a pulse oximetry device. ORi, pulse oximetry, PI, and PVI values were measured continuously. Sensitivity, specificity, positive and negative predictive values, likelihood ratios, and accuracy were calculated for ORi values equal to zero in different time points during surgery to predict hypoxemia. At Clinicaltrials.gov registry, the Registration ID is NCT05050552. Hypoxemia was observed in 19 patients (38%). The accuracy for predicting hypoxemia during anesthesia induction at ORi value equals zero at 5 min 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). For predicting hypoxemia, ORi equals zero show good sensitivity, specificity, and statistical accuracy values for time points of DS5 until OLV30 where the sensitivity of 43.8%, specificity of 64%, and an accuracy of 56.1% were recorded. ORi and SpO2 correlation was found at DS5, 5 min after lateral position with two-lung ventilation (DL5) and at 10 min after OLV (OLV10) (p = 0.044, p = 0.039, p = 0.011, respectively). Time-dependent correlations also showed that; at a time point of DS5, ORi has a significant negative correlation with PI whereas, no correlations with PVI were noted. During the use of OLV for thoracic surgeries, from 5 min after intubation (DS5) up to 30 min after the start of OLV, ORi provides valuable information in predicting hypoxemia defined as SpO2 less than 95% on pulse oximeter at FiO2 higher than 50%.

Sagiroglu G ，Baysal A ，Karamustafaoglu YA 《BMC Anesthesiology》

Oxygen Reserve Index Predicts Hypoxemia During One-Lung Ventilation: An Observational Diagnostic Study.

To determine the accuracy of the Oxygen Reserve Index (ORi) to predict hypoxemia during one-lung ventilation (OLV). An observational diagnostic test study. A tertiary care teaching hospital. Forty consecutive patients scheduled for thoracic surgery with OLV. Patients were ventilated with tidal volumes of 8 mL/kg ideal body weight during two-sided ventilation and 6 mL/kg during OLV, and with fraction of inspired oxygen (FIO2) of 60%. ORi was measured continuously. Sensitivity, specificity, positive and negative predictive values, likelihood ratios, and accuracy were calculated for ORi = 0 in different phases of anesthesia. Hypoxemia during OLV was defined as SpO2 < 90%. Hypoxemia owing to malpositioning of the double lumen tube was an exclusion criterion. ORi = 0 five minutes after tracheal intubation in the supine position showed a sensitivity of 63.6% (confidence interval [CI] 95% 31.6-87.6), specificity of 93.1% (95% CI 75.8-98.8), and an accuracy of 85.0% (95% CI 69.5-93.8). The rate of hypoxemia was 27.5% (95% CI 15.14-44.14). An ORi value equal to zero, 5 minutes after the onset of mechanical ventilation in the supine position, predicts the development of hypoxemia during OLV. These findings may be helpful to adjust FIO2 individually in patients undergoing OLV and to avoid unnecessary high concentrations of oxygen.

Alday E ，Nieves JM ，Planas A 《-》

Oxygen reserve index guided oxygen titration in one lung ventilation with low fresh gas flow.

Continuous oxygen reserve index (ORI) measurement with multiple wave pulse co-oximetry is a noninvasive measurement. The decrease in the ORI trend provides a prediction for the development of hypoxemia and provides info rmation on hyperoxia. Our aim is to determine the effect of ORI-guided oxygen titration on hyperoxemia-mediated morbidity. Consecutive 120 ASA I-III patients, 18–70 years of age, without severe obstruction or restriction, undergoing one lung ventilation (OLV), were included in the study. Patients were divided into 4 groups. Oxygen titration without ORI monitoring with low-flow anesthesia (1 L/min, Group 1, n = 25) and high-flow anesthesia (4 L/min, Group 2, n = 28). Oxygen titration by ORI monitoring with low flow anesthesia (1 L/min, Group 3, n = 25) and high flow anesthesia (4 L/min, Group 4, n = 25). FiO2 increased up to 100% if necessary. OLV time, duration of surgery and anesthesia, FiO2 applied during OLV, oxygen application time (T) over 60%, vital signs, hospital and ICU stay time, and complications were recorded. There was a statistically significant difference in terms of FiO2 used during OLV (p < 0.05). There was no difference in ORI values (p < 0.05). In Group 3, both PaO2 and SpO2 were significantly lower than the others both before and during OLV. There was no significant difference in terms of ORI parameters between low flow and high flow anesthesia groups. There was a strong, positive correlation between the duration of hospital stay and FiO2 used above 80% during OLV. We concluded that ORI-guided thoracic anesthesia may reduce hospital stay and increase patient safety.

Saraçoğlu A ，Yamansavcı Şirzai E ，Yıldızeli B ，Yüksel M ，Aykaç ZZ ... -  《-》

Monitoring the Oxygen Reserve Index can contribute to the early detection of deterioration in blood oxygenation during one-lung ventilation.

Koishi W ，Kumagai M ，Ogawa S ，Hongo S ，Suzuki K ... -  《-》

Continuous Titration of Inspired Oxygen Using Oxygen Reserve Index to Decrease Oxygen Exposure During One-Lung Ventilation: A Randomized Controlled Trial.

A high fraction of inspired oxygen (Fio2) is administered during one-lung ventilation (OLV). However, a high Fio2 is not physiologic and may lead to various complications. We hypothesized that continuous titration of Fio2 using the oxygen reserve index (ORI) reduces oxygen exposure compared to conventional management during OLV. In this randomized, double-blinded trial, patients undergoing thoracic surgery were assigned to an ORI (n = 64) or a control group (n = 60). In the ORI group, ORI was continuously displayed using multiwavelength pulse co-oximetry (Masimo) between 0 and 1 (0, no reserve; 1, maximum reserve), and Fio2 was titrated for a target ORI of 0.21 at 5-minute intervals during OLV. In the control group, Fio2 was adjusted using arterial blood gas analysis measured at 15 minutes after OLV initiation. The primary end point was the time-weighted average Fio2 during OLV. Overall, time-weighted average Fio2 did not differ between the groups (control versus ORI: median [interquartile range], 0.87 [0.73-1.00] vs 0.82 [0.68-0.93]; P = .09). However, in a subgroup analysis, the ORI group reduced time-weighted average Fio2 after pulmonary vascular ligation compared to the control group (control versus ORI: median [interquartile range], 0.75 [0.70-1.00] vs 0.72 [0.59-0.89]; P = .0261). The incidence of intraoperative hypoxia (arterial oxygen saturation [Spo2] <94%; control versus ORI: 32% [19/60; 95% confidence interval (CI), 20-45] vs 19% [12/64; 95% CI, 10-31]; P = .09), and postoperative complications within the first 7 days did not differ between the groups. ORI-guided continuous Fio2 titration does not reduce overall oxygen exposure during OLV.

Yang M ，Kim JA ，Ahn HJ ，Choi YS ，Park M ，Jeong H ，Kim K ，Lee NY ... -  《-》