Selection and placement of oral ventilation tubes based on tracheal morphometry

Objective/hypothesis: Evidence-based guidelines for the selection of appropriately sized ventilation tubes as well as their placement do not exist, although iatrogenic injuries to the trachea and larynx following endotracheal intubation are not infrequent. Our objective was to provide selection recommendations for ventilation tubes based on anatomic criteria.

Study design: Prospective cross-sectional study at a tertiary care hospital.

Methods: From January 2010 to June 2010 all patients more than 16 years who underwent computer tomography of the neck were included. Contraindications were intubation, tracheotomy, fractures of the lower jaw, tumors, and head or neck deformities. Radiologic data was used to determine the distance between the lower incisors and cricoid cartilage and the smallest laryngotracheal diameter. The results were correlated with patient characteristics and compared with properties of ventilation tubes.

Results: One hundred fifty-nine patients were included in the study. The laryngotracheal constriction was subcricoidal with a mean diameter of 15.5 ± 3.2 mm coronal and 17.1 ± 2.6 mm sagittal. The mean distance between lower incisors and cricoid cartilage was 176.5 ± 14.8 mm. Patient height correlated significantly with the coronal subcricoid tracheal diameter (r = .51; P < .001) as well as with the distance between lower incisors and cricoid cartilage (r = .64; P < .001). No statistically significant gender or age-related correlations were found. Despite having the same specifications, tubes from different manufacturers differed considerably in their dimensions.

Conclusions: Selection of size and placement of ventilation tubes can be based on patient height. Considerable differences in the dimensions of ventilation tubes necessitate a height-based nomogram for evidence-based tube selection and placement. A uniform system of tube labeling based on biometric data is required.