Determining the Depth of the Endotracheal Tube by Topographic Measurement

Im, Chang Woo; Park, Sang O; Hong, Dae Young; Baek, Kwang Je; Kim, Jin Young; Lee, Kyeong Ryong

Abstract

PURPOSE: Malposition of an endotracheal tube tip may induce several complications. Prediction of the depth of the endotracheal tube is important and should be individualized. Here we propose a topographic method to predict the proper depth of the endotracheal tube and compare it with a conventional method (CM).
METHODS
We enrolled 127 patients who were intubated in the ED or the ICU. To measure tube depth, we used 3 topographic methods: method 1 (M1): length from lateral side of lip to mandible angle + length from mandible angle to sternal angle; Method 2 (M2): sternum length; Method 3 (M3): length from the acromioclavicular joint to the nipple level on an anterior axillary line. Correlations between the ideal depth of the endotracheal tube and the length measured by topographic methods were studied and the ratio of the actual depth to the targeted (ideal) depth was calculated. We compared ratios between CM and topographic methods.
RESULTS
Correlation coefficients between ideal depth and topographic measurement were 0.558 (M1), 0.469 (M2), and 0.301 (M3). Targeted intubation depth in the total group was 91(71.7%) for CM, 101(79.5%) for M1, 95(74.8%) for M2, and 90(70.9%) for M3. Among females, targeted intubation depth was 38(66.7%) for CM, 49(86%, p<0.05) for M1, 43(75.4%) for M2, and 44(77.2%) for M3.
CONCLUSION
The topographic method is simple and rapid, and may be useful for individualizing measurement to each patient. Using a topographic method is expected to reduce complications during intubation in the ED, especially in women and when Method 1 is used.