Dyspnea perception during the inspiratory resistive loads test in obese subjects waiting bariatric surgery

Identification of low dyspnea perception is relevant, since this condition is significantly associated with worse outcomes. We investigated dyspnea perception during the inspiratory resistive loads test on obese subjects waiting bariatric surgery in comparison with normal subjects. Secondarily, we analysed the proportion of obese subjects with low, moderate and high dyspnea perception. This observational study included subjects with body mass index (BMI) ≥ 35 kg/m², compared to healthy subjects with BMI ≥ 18 and <25 kg/m². Subject underwent clinical evaluation, inspiratory test with progressive resistive loads and spirometry. We studied 23 obese subjects (mean BMI = 51.9 ± 9.3 kg/m²) and 25 normal subjects (mean BMI = 24.3 ± 2.3 kg/m²). With the increase magnitude of resistive loads there was a significant increase in dyspnea score (p < 0.001) and progressive increase of the generated inspiratory pressure (p < 0.001), but there was no difference between the groups in terms of dyspnea score (p = 0.191) and no interaction effect (p = 0.372). Among the obese subjects, 4 individuals were classified as low perception, 11 as moderate and 8 as high. In conclusion, the degree of dyspnea perception during the inspiratory progressive resistive loads test did not differ between obese and normal subjects. Among obese subjects, only 17% were classified as low dyspnea perception.