Dimensional Variations of Left-Sided Double-Lumen Endobronchial Tubes

Common double-lumen tube selection methods overestimate adequate tube sizes in individual patients - a 3D reconstruction study

BACKGROUND

Appropriate selection of double-lumen tube sizes for one-lung ventilation is crucial to prevent airway damage. Current selection methods rely on demographic factors or 2D radiography. Prediction of left bronchial diameter is indispensable for choosing the adequate tube size. This prospective observational study investigates if current selection methods sufficiently predict individuals' left bronchial diameters for DLT selection compared to the 3D reconstruction.

METHODS

100 patients necessitating thoracic surgery with one-lung ventilation and left-sided double-lumen tubes, ≥ 18 years of age, and a set of chest X-rays and 2D thorax CT scans for 3D reconstruction of the left main bronchus were included between 07/2021 and 06/2023. The cross-validated prediction error and the width of the 95%-prediction intervals of the 3D left main bronchial diameter utilizing linear prediction models were based on current selection methods.

RESULTS

The mean bronchial diameter in 3D reconstruction was 13.6 ± 2.1 mm. The ranges of the 95%-prediction intervals for the bronchial diameter were 6.4 mm for demographic variables, 8.3 mm for the tracheal diameter from the X-ray, and 5.9 mm for bronchial diameter from the 2D-CT scans. Current methods violated the suggested '≥1 mm' safety criterion in up to 7% (men) and 42% (women). Particularly, 2D radiography overestimated women's left bronchial diameter. Current methods even allowed the selection of double-lumen tubes with bronchial tube sections greater than the bronchial diameter in women.

CONCLUSIONS

Neither demographic nor 2D-radiographic methods sufficiently account for the variability of the bronchial diameter. Wide 95%-prediction intervals for the bronchial diameter hamper accurate individual double-lumen tube selection. This increases women's risk of bronchial damage, particularly if they have other predisposing factors. These patients may benefit from 3D reconstruction of the left main bronchus.

TRIAL REGISTRATION

Not applicable.

Comparisons of the segments of left-sided double-lumen tracheobronchial tubes as industrial products

BACKGROUND

Although there are at least seven manufacturers producing left-sided double-lumen tubes (DLTs), there have been few reports comparing the segments of these DLTs. In this study, we compared various segments of left-sided DLTs further.

MATERIALS AND METHODS

We examined five manufacturers' left-sided DLTs: Mallinckrodt, Portex, Rüsch, Sheridan, and Daiken-medical. We conducted the following six trials or measurements, and three supplemental trials or measurements: First, we tried to pass various sizes of steel balls down each lumen in order from the smallest (3 mm) to largest (4.5 mm). If the ball passed on the first attempt, we tried just once; otherwise, we made a second attempt. Second, we measured the external diameter of tracheal and bronchial cuff using a profile projector. Third, we measured the length of the cuff and tip of the bronchial segment of the tubes using the profile projector. Fourth, we measured various lengths of the tubes. Fifth, we measured the external diameter of both lumens and the tubules for tracheal and bronchial cuff inflation. Finally, we measured various cross-sectional areas including the tracheal lumen, bronchial lumen, and tubules for cuff inflation. We also conducted three supplemental studies. First, we measured air volume in the cuff when intracuff pressure equaled 2 or 3 kPa. Second, we defined the configuration of the tracheal and bronchial cuffs. Third, we defined the presence or absence of bevels and also measured the angle of the bevels using the profile projector.

RESULTS

We performed nine trials and measurements and found large disparities between each manufacturer's tubes.

CONCLUSIONS

The large disparities found between the measurements of the five manufacturers' tubes may be due to different lots or changes in specifications made by each manufacturer. We found tubes exhibiting lower quality, such as deformations, and non-universal and inconsistent sizing, in the comparison of the manufacturers' tubes. Practitioners should be aware of the features and aspects of these tubes.

Compatibility of left-sided double-lumen endobronchial tubes with tracheal and bronchial dimensions: a retrospective comparative study

BACKGROUND

Double-lumen endobronchial tubes (DLT) continue to be the most widely used method for obtaining lung isolation during anesthesia. We compared recommendations for DLT size selection with radiologically assessed lower airway dimensions gathered from a large patient population.

METHODS

For this retrospective comparative study, we assessed computed tomography (CT) scans of 150 adults with no known airway pathologies. Using these scans, we measured the diameter and length of the trachea and the diameter of the mainstem bronchi. These airway dimensions were then compared to the dimensions of left-sided DLTs of three different manufacturers. Size selection was based on one standard textbook's recommendations.

RESULTS

We found the recommended DLT sizes were occasionally too small but more often too large, particularly in the endobronchial airway. With the DLT Vivasight-DL®, mismatching occurred in 28.7% (43/150) of the patients at the distal mainstem bronchus and 8% (12/150) at the tracheal level. This mismatching happened most often in females (left distal mainstem bronchus 34/68, 50%; trachea 9/68, 13.2%). Conversely, the DLT was more often too small for male patients in both the left main bronchus (SHER-I-BRONCH®: 8/82, 9.8%) and the trachea (SHER-I-BRONCH®: 2/82, 2.4%). The endobronchial tube portion was more often too long in females (Vivasight® DLT: 11/68, 16%) than males (9/82, 11%).

CONCLUSIONS

A considerable proportion of the recommended DLT sizes from all three manufacturers was incompatible with individual patient's lower airway dimensions.