Automated measurement of tracheal and main bronchial diameters: a feasibility study

A thoracic computed tomography scan is rarely used to help choose the appropriate double-lumen tube. Nowadays, bronchial measurements can be automated using dedicated software. The aim of this prospective monocentric study was to compare manual and automated measurements of the diameter of the trachea and both main bronchi in adult patients free from a history of lung surgery or disease.

Diameters of the trachea and of the main stem bronchi were measured by trained physicians or automatically using Thoracic Volume Computer Assisted Reading software (GE Healthcare, Chicago, IL, USA). Manual measurements were considered as the goal standard.

Two hundred and forty-three patients were assessed for eligibility, 216 were allocated to intervention and 173 analyzed: 102 males and 71 females (61.4±13.9 years, 169.7±9.4 cm, 73.3±16.8 kg). Reliability between the two investigators was poor (20.8±9.0% of measurements with a difference >10%). Intraclass correlation coefficient (ICC) and its confidence interval at 95% (ICC [95% CI]) was 0.97 [0.96; 0.98] for the maximal diameter and 0.94 [0.92; 0.95] for the minimal diameter of the trachea (P<0.01 for both). ICC [95% CI] was 0.97 [0.94; 0.98] for the maximal diameter and 0.93 [0.90; 0.95] for the minimal diameter of the right main bronchus (P<0.01 for both). ICC [95% CI] was 0.96 [0.95; 0.97] for the maximal diameter and 0.93 [0.90; 0.95] for the minimal diameter of the left main bronchus (P<0.01 for both).

This feasibility study has mixed results since automated measurements were not feasible in around 20% of the cases.