Efficacy of height-based formula to predict insertion depth of left-sided double lumen tube: A prospective observational study.

The insertion depth of the left-sided double-lumen tube needs careful positioning and bronchoscopic confirmation. Several formulae based on body height have been used for estimating the optimal insertion depth of a left-sided double-lumen tube. We conducted this prospective study to test the hypothesis that our earlier developed height-based formula (0.