Dyspnea perception during the inspiratory resistive loads test in obese subjects waiting bariatric surgery
Objectives: To assess the degree of dyspnea perception during the inspiratory resistive loads test on obese subjects waiting bariatric surgery in comparison with normal subjects. Secondarily, to analyse the proportion of obese subjects with low, moderate and high perception of dyspnea. Methods: Cross-sectional study, including subjects with body mass index (BMI) ≥ 35 kg/m2, compared to healthy subjects with BMI ≥ 18 and < 25 kg/m2. Each subject underwent clinical evaluation, inspiratory test with progressive resistive loads to quantify dyspnea perception (modified Borg scale) and spirometry. Results: 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). Obese subjects generate higher inspiratory pressures than normal subjects (p=0.009) with progressive increase throughout the different resistive loads (interaction effect=0.009). Among the obese subjects, 4 individuals were classified as low perception, 11 as moderate and 8 as high. There was a significant association between age and dyspnea perception (p=0.008), with the average age higher in the low perception group. Conclusions: The degree of dyspnea perception during the inspiratory progressive resistive loads test did not differ between obese and normal subjects. Among obese subjects, 17% were classified as lower dyspnea perception, 48% as moderate dyspnea perception and 35% as high dyspnea perception.