ABSTRACT
Objective To investigate the correlation between the insertion depth of the left-sided double-lumen tube (DLT) and some specific body landmarks in order to guide left-sided DLT intubation. Methods Ninety-five adult patients who underwent thoracic surgery were chosen, and the age (A), sex (S), height (H), weight (W), distance between the cricothyroid membrane and upper notch of the sternum angle (L), size of the left-sided DLT (F), and predicted depth of intubation (y) were recorded. After anesthesia induction, the final corrected insertion depth of the left-sided DLT (Y) were recorded using fiberoptic bronchoscopy. The Y and y were compared.Linear regression and Pearson's correlation analysis were used to analyze the data. Results There was no difference between the Y and y (P＞ 0.05). The Y was significantly correlated with H, W, and L (P ＜ 0.01), and was not correlated with A (P＞ 0.05). Three linear regression equations for H, L, and Y were obtained. H and L were linearly dependent on Y, and the determination coefficients R2 were 0.43 (Y=7.285+0.128 H) and 0.41 (Y=19.305+0.866 L), respectively. Using both H and L as the independent variables, the determination coefficient R2 was 0.56 (Y=8.127+0.087 H+0.559 L). Conclusion The linear regression equation Y=8.127+0.559 H+0.087 L could be used as a rapid method to assess the insertion depth of the left-sided DLT. However, the ideal insertion depth of the left-sided DLT still needs to be confirmed using fiberoptic bronchoscopy.