Accuracy of the ratio of tidal volume to corrected forced vital capacity in predicting driving pressure increase during one-lung ventilation / 中华麻醉学杂志

ABSTRACT

Data of patients underwent thoracic surgeries were retrospectively collected in our center from November 2016 to January 2019.The last recorded tidal volume and driving pressure before two-lung ventilation were selected.Patents were classified into driving pressure increase group (>15 cmH 2O) and normal group.The baseline characteristics, parameters of pulmonary function, left one-lung ventilation and protective ventilation strategies were recorded.Logistic regression analysis was used to identify the risk factors for driving pressure increase, correlation analyses between predicted body weight and total lung capacity and between forced vital capacity and total lung capacity were performed.The Receiver Operating Characteristic (ROC) curve was used to analyze the accuracy of the ratio of tidal volume to corrected forced vital capacity in predicting driving pressure increase.Sixty-two patients were included in this study.Body mass index, left one-lung ventilation and the ratio of tidal volume to corrected forced vital capacity ratio were the risk factors for driving pressure increase ( P<0.05 or 0.01). Predicted body weight (correlation coefficient was 0.66, P<0.01) and forced vital capacity (correlation coefficient was 0.75, P<0.01)were both positively correlated with total lung capacity, but the two coefficients were statistically significant difference ( P<0.05). The area under the ROC curve of the ratio of tidal volume to corrected forced vital capacity in predicting driving pressure increase was 0.846 (95% CI 0.749-0.943) ( P<0.01), the diagnostic threshold was 0.312, the sensitivity and specificity of this threshold were 0.800 and 0.781 respectively, so the boundary of tidal volume during one-lung ventilation should be either forced vital capacity×0.149 for left one-long ventilation or forced vital capacity×0.163 for right one-lung ventilation.In conclusion, the ratio of tidal volume to corrected forced vital capacity has a higher predictive value for driving pressure increase during one-lung ventilation, and forced vital capacity can be used as a reference while calculating tidal volume.