Pulmonary Function in Morbid Obesity: Influence of Sex and Body Distribution

Objective: To describe the respiratory functional alterations that occur in patients with morbid obesity (MO) and the possible influence of gender and distribution of body fat, measured as an index waist/hip ratio (wai/hip). Method: Prospective study in 2 years of anthropometric and functional parameters breathing in MO, determining age, body mass index (BMI), waist, hip, wai/hip index, blood gas values, flow-volume curve, plethysmography, diffusion of CO and maximum inspiratory (MIP) and expiratory (PEM) pressures. The results between men and women and the relationship between respiratory parameters and wai/hip index are compared. Results: We studied 171 patients, 80 men and 91 women, with 44 ± 12 years, weighing 130 ± 22 kg, with BMI of 48 ± 6 Kg/m2 and wai/hip index of 0.989-0.097 ± 48. There is a decrease in lung function parameters in the MO, showing men MIP worse, but better MEP, than women. Hypoxemia is common (55%), related to an older and worse flows and static volumes. Hypercapnia is 15% more common in men, and is related to the decrease in expiratory flows and increased residual volume. Wai/hip index does not correlate with respiratory parameters in the MO. Conclusions: Morbid obesity affects respiratory blood gas and has functional alterations. There are differences between men and women in the presence of hypercapnia and maximal respiratory pressures, without influencing the type of obesity messured with the wai/hip index.