The Depth of Insertion for Left-Sided Double-Lumen Endotracheal Tube is Correlated with the Height and the Length of Sternocleidomastoid Muscle / 대한마취과학회지

BACKGREOUND: When a double-lumen endotracheal tube (DLT) is used for one-lung ventilation, its position should be accurate. But only a few studies has been performed about how to predict the depth of insertion for DLT preoperatively. The purpose of this study is to investigate which physical measurements are correlated with the depth of insertion for left-sided DLT and how the depth of insertion for DLT can be explained with these physical measurements. METHODS: After placing a 5 cm-high pillow under the patient's head, we intubated left-sided disposable DLT (BronchocathTM, Mallinckrodt medical Ltd, USA) in 65 adults. We tape-measured sternocleidomastoid muscle (SCM) length and sternal length. We positioned the proximal margin of the bronchial cuff of DLT just below carinal bifurcation through fiberoptic bronchoscope, and recorded the depth of insertion for DLT at the upper incisor level. RESULTS: The depth of insertion for DLT was correlated with both height (y=3.96+0.15x, r2=0.51, p=0.0001) and SCM length (y=16.73+0.82x, r2=0.49, p=0.0001). Sternal length (r2=0.11, p=0.0081) was weakly correlated with the depth of insertion for DLT. The best regression model was depth of insertion for DLT (cm)=6.88+0.09 height (cm)x0.46 SCM length (cm). CONCLUSIONS: The depth of insertion for DLT is correlated with SCM length as well as height. So we may use them in predicting the depth of insertion for DLT.

Metric Study of Upper Airway and Trachea in Nomal Korean Adults uing Fiberoptic Bronchoscopy: Study of endotracheal tube fixation positioning in adults / 대한마취과학회지

BACKGROUND: Neck flexion risks endobroncheal intubation when the tracheal tube is not in the proper position. So accurate knowledge of upper airway length is required to prevent malpositioning of endotracheal tubes. Therefore we evaluated the length of various portions of upper airway in Korean adults (n=500) who had no abnormality of upper airway. METHODS: Five hundred patients, composed of 198 males and 302 females who underwent elective surgery, were included in this study. After endotracheal tube was placed under general anesthesia, we measured the distance from tube machine-end to upper incisor (value 1), from tube machine-end to inferior margin of cricothyroid membrane (value 2), and from tube machine-end to carina (value 3) by means of fiberoptic bronchoscopy. RESULTS: The mean length between upper incisor and inferior margin of cricothyroid membrane (value 2 - value 1) was 12.7 cm in males and 11.6 cm in females, while the mean length between superior margin of cricoid cartilage and carina (value 3 - value 2) was 12.9 cm in males and 11.3 cm in females. So the mean length between upper incisor and the mid portion of trachea was nearly 19.6 cm in males and 17.7 cm in females. CONCLUSIONS: We believe that, based on the findings in this study, the safety length for endotracheal tube fixation is 20 cm in Korean adult males and 18 cm in Korean adult females.