BACKGROUND:
One-lung ventilation (OLV) is widely utilized in thoracic surgeries performed under general anesthesia. However, transpulmonary shunting can potentially cause severe hypoxemia during OLV. Although several predictors of hypoxemia during OLV have been proposed, no single factor can independently predict hypoxemia accurately. Therefore, we made a simple prediction model of hypoxemia during OLV with multiple predictors.
METHODS:
 A single-center retrospective review was performed of consecutive patients who underwent lung resection surgery between January 2014 and December 2016. We defined hypoxemia during OLV as a SpO2 lower than 91% with a FiO2 of 1.0, as when either lung oxygen insufflation or continuous positive airway pressure were required to a non-dependent lung, or as when intermittent two lung ventilation was required. Patients were randomized into a derivation group (75% of patients) and a validation group (25% of patients). A prediction model for hypoxemia during OLV was developed by using a regression coefficient-based scoring method. The discriminatory power of the resulting score was assessed by calculating the cross-validated C statistic.
RESULTS: 
A total of 763 patients underwent lung resection surgery for lung cancer during the study period. Among them, 256 patients were excluded because of missing data and 27 patients were excluded because of tube malposition during OLV. In the derivation group, backward multivariable logistic regression analysis identified three covariates that were significant independent predictors, and we used for our hypoxemia prediction score. The discriminatory power of this model was fair, with a cross-validated C statistic of 0.81 in the derivation group and 0.87 in the validation group. 
CONCLUSION:
This simple prediction model identifies the preoperative risk of hypoxemia during OLV. This score has the potential to easily identify patients who may need a more intensive ventilation strategy for OLV.

01 / A Simple Prediction Model of Hypoxemia During One-Lung Ventilation