Ultrasonography and videobronchoscopy to assess the subglottic diameter in the paediatric population: a first look

The aim of the study was to evaluate the efficacy of ultrasonography and videobronchoscopy in measuring the subglottic diameter in the paediatric population.

A double-blinded, prospective clinical study carried out at the Montreal Children's Hospital, McGill University.

Children undergoing non-life-threatening bronchoscopy for various reasons had the subglottic diameters measured with ultrasonography, videobronchoscopy, and the traditional method of endotracheal tube sizing during the operative period. Ten patients were enrolled in the study. Parental consent was obtained prior to the procedure.

Statistical analysis revealed that although ultrasonography was highly correlated with both videobronchoscopy and endotracheal tube sizing in measuring the subglottic diameter in the paediatric population, the measurements were not accurate in giving an exact value of the diameters in question. Videobronchoscopy was found to highly correlate with endotracheal tube sizing but had values that were slightly larger.

This study is the first to examine the ability of ultrasonography and videobronchoscopy in evaluating the subglottic diameter in the paediatric population. Videobronchoscopy was shown to correlate highly with the present standard of measurement, namely, endotracheal tube sizing. The difference in measurement between the two was shown to be statistically significant, with videobronchoscopy being the consistently larger of the two. These results are in keeping with the limitations of measurement by the endotracheal tube. Similarly, ultrasonography was also correlated with both videobronchoscopy and endotracheal tube sizing. In contrast, ultrasonography was found to provide measurements that were significantly smaller than the other two methods. This suggests that ultrasonography may be a good technique to follow the change in lesions of the subglottis but may be poor for absolute measurements of this area as it always underestimated the size of the lumen.