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

Gonul Sagiroglu,Ayse Baysal,Yekta Altemur Karamustafaoglu

doi:10.1186/s12871-021-01539-8

Abstract

BackgroundOur 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).MethodsFifty 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.ResultsHypoxemia 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.ConclusionsDuring 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%.

Highlights

One‐lung ventilation and thoracic surgeries There is an ongoing investigation to provide advanced monitoring techniques during thoracic surgeries that require one-lung ventilation (OLV)
The data analysis shows that; for predicting hypoxemia, oxygen reserve index (ORi) equals to zero show good sensitivity, specificity and accuracy statistical values for time points of DS5 until OLV30 where sensitivity of 43.8%, specificity of 64%, and an accuracy of 56.1% were recorded. These findings correlated to the previous reports that hypoxic pulmonary vasoconstriction (HPV) increases and intrapulmonary shunting decreases after the start of OLV within 30 to 60 min [4, 8, 13, 14]
There are other time points where there is statistically good report of sensitivity, specificity and accuracy for time points at ORiDL5, and during OLV until OLV30 where sensitivity of 43.8%, specificity of 64%, and an accuracy of 56.1% are recorded

Summary

Introduction

One‐lung ventilation and thoracic surgeries There is an ongoing investigation to provide advanced monitoring techniques during thoracic surgeries that require one-lung ventilation (OLV). There is perfusion in this lung, causing a transpulmonary shunt without ventilation. The transpulmonary shunt in the non-dependent lung is the main reason for hypoxemia during OLV. This hypoxemia in the upper deflated lung causes a physiological mechanism called hypoxic pulmonary vasoconstriction (HPV) which is responsible for diverting blood flow from the non-ventilated lung to the ventilated lung. HPV causes a decrease in ventilation-perfusion mismatch and improves arterial oxygenation [1,2,3,4]. 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)

Objectives

Methods

Results

Discussion

Conclusion