Impact of surgically-induced weight loss on respiratory function: a prospective analysis

Morbid obesity (MO) causes several degrees of respiratory impairment that may resolve after weight reduction. The aims of the present study were to investigate the frequency of respiratory impairment in a selected cohort of morbidly obese patients with BMI 40-50 kg/m(2) with no respiratory symptoms and to evaluate the impact of surgically-induced weight loss on respiratory function.

Prospective analysis of respiratory impairment was conducted before surgery and 1 year after surgery in a cohort of patients with MO who underwent vertical banded gastroplasty (VBG). 30 consecutive patients with MO who underwent VBG (14 open and 16 laparoscopic) in a 1-year period were studied. Respiratory function tests, arterial blood gases and hemoglobin were obtained in all patients before and 1 year after VBG.

Results were analyzed using the Wilcoxon signed-rank test and Spearman for variables without normal distribution. Mean age was 35+/-8 years; there were 3 males and 27 females. BMI was 44+/-4 kg/m(2) before surgery and 32+/-4 kg/m(2) at 1-year follow-up. By respiratory function tests, the diagnosis of obstructive disease was made before surgery in 4 patients and a restrictive disorder was identified in 4 additional patients. Evidence of pulmonary disease was absent in all patients 1 year after surgery. Forced vital capacity, inspiratory and expiratory forces, tidal volume, SaO(2), and PaCO(2) significantly improved after weight reduction.

Surgically-induced weight loss significantly improves pulmonary function.