For their study, Copley and her colleagues used computed tomography, or CT, an imaging technology capable of providing detailed pictures of the lungs and airways, to evaluate the effects of obesity on the lungs and the trachea in 51 obese patients who underwent bariatric surgery. They used CT to measure the size and shape of the trachea and assess “air trapping,” a sign of lung obstruction in which excess air remains in the lungs after exhaling, resulting in a reduction in lung function.
Bariatric surgery is a widely used treatment for obese patients who haven’t responded to other weight-loss approaches. The procedure effectively reduces the size of the stomach.
All of the study participants lost weight following surgery, with a mean body mass index decrease of 10.5 kg/m2 — about 23 pounds. When the researchers compared results at baseline and six months after surgery, they found that surgery and weight loss were associated with structural changes to the lung and trachea.
In fact, post-surgery CT images showed reductions in air trapping and a lower incidence of tracheal collapse. Study participants with more significant changes in the extent of CT air trapping were more likely to experience less shortness of breath, the authors noted.
According to Copley, the results suggest that there may be a reversible element of small airway inflammation related to obesity and that reversal of this inflammation correlates with improvement in symptoms. The findings also point to CT as a potential way for measuring and assessing airway inflammation.
“CT is a useful [structural] marker to demonstrate subtle changes, which are not easily assessed by lung function alone,” Copley said.