Masanobu Yasumoto

Optimal depth of insertion of left-sided double-lumen endobronchial tubes cannot be predicted from body height in below average-sized adult patients

Background and objective: The optimal depth of insertion of left‐sided double‐lumen endobronchial tubes is strongly correlated with body height in average‐sized adults. However, this relationship has not been studied in below average‐sized adult patients. We investigated whether or not there is a clinically useful relationship in below average‐sized adult patients. Methods: One hundred and ninety six consecutive adult patients undergoing thoracic surgery under one‐lung anaesthesia (body height ≤ 155 cm) were included in this study. Left‐sided double‐lumen tubes were inserted under the guidance of a fibre‐optic bronchoscope. Optimal depth was defined as the proximal surface of the bronchial cuff positioned just below the carina. Results: There was a statistically significant positive correlation between body height and the optimal depth of insertion (r = 0.61, P < 0.0001); however, the correlation coefficient was low. The actual optimal depth of insertion of one patient was even 4.5 cm shorter than that obtained from the equation. Conclusion: Although there was a statistically significant correlation between body height and the optimal depth of insertion of left sided double lumen tubes in adult patients of short stature (≤ 155 cm), clinical application of the equation is not warranted and these tubes should be inserted under direct vision with a fibre‐optic bronchoscope.