Is there a correlation of sonographic measurements of true vocal cords with gender or body mass indices in normal healthy volunteers?

Background: Ultrasound is a readily available, non-invasive technique to visualize airway dimensions at the patient′s bedside and possibly predict difficult airways before invasively looking; however, it has rarely been used for emergency investigation of the larynx. There is limited literature on the sonographic measurements of true vocal cords in adults and normal parameters must be established before abnormal parameters can be accurately identified. Objectives: The primary objective of the following study is to identify the normal sonographic values of human true vocal cords in an adult population. A secondary objective is to determine if there is a difference in true vocal cord measurements in people with different body mass indices (BMIs). The third objective was to determine if there was a statistical difference in the measurements for both genders. Materials and Methods: True vocal cord measurements were obtained in healthy volunteers by ultrasound fellowship trained emergency medicine physicians using a high frequency linear transducer orientated transversely across the anterior surface of the neck at the level of the thyroid cartilage. The width of the true vocal cord was measured perpendicularly to the length of the cord at its mid-portion. This method was duplicated from a previous study to create a standard of measurement acquisition. Results: A total of 38 subjects were enrolled. The study demonstrated no correlation between vocal cord measurements and patient′s characteristics of height, weight, or BMI′s. When accounting for vocal cord measurements by gender, males had larger BMI′s and larger vocal cord measurements compared with females subjects with a statistically significant different in right vocal cord measurements for females compared with male subjects. Conclusion: No correlation was seen between vocal cord measurements and person′s BMIs. In the study group of normal volunteers, there was a difference in size between the male and female vocal cord size.