Does body mass index predict tracheal airway size?

OBJECTIVES/HYPOTHESIS: To determine the relationship between body mass index along with other anthropomorphic variables as they relate to tracheal airway dimensions.

STUDY DESIGN

Retrospective case series.

METHODS

This was a radiographic study of 123 consecutive hospitalized patients undergoing tracheotomy over a 4-year period (2007-2011). We measured airway dimensions in axial computed tomography imaging and made comparisons with height, weight, body mass index, gender, and age. Measurements were taken at the first tracheal ring level including anterior-posterior length, width, and calculated area. We expected higher body mass index not to be a good predictor of larger airway dimensions.

RESULTS

The linear regression model showed body mass index was significantly inversely related to tracheal width after controlling for gender and age (P = .0389). For every 1 kg/m(2) increase in body mass index, the tracheal width decreased by 0.05 mm. There was a trend for airway area to diminish with increasing body mass index.

CONCLUSIONS

These results are consistent with the hypothesis that obese patients do not have larger airways. Our study indicated a trend toward smaller airways as body mass index increased. Specifically, as body mass index increases, tracheal width appears to decrease. This information should help medical professionals avoid the tendency to use a larger tube to secure the airway of an obese patient. Hopefully, this will result in further research into the field and may prevent future airway injuries in a society where obesity has become epidemic.

LEVEL OF EVIDENCE

4 Laryngoscope, 125:1093-1097, 2015.