Christiane Aires Teixeira, José Ernesto dos Santos, Gerusa Alves Silva,
Elisa Sebba Tosta de Souza, José Antônio Baddini Martinez
Objective: To investigate dyspnea in individuals with Class II or III obesity and look for correlations among the respiratory data related to
such individuals. Methods: This study involved 49 subjects with a body mass index >35 kg/m2, divided into two groups (those with dyspnea
and those without). The baseline dyspnea index was evaluated, as were spirometry findings, maximal respiratory pressures and arterial blood
gas analysis. Results: Of the 49 subjects evaluated, 37 reported dyspnea and 12 reported no dyspnea. The baseline dyspnea index differed
between the two groups. The mean values were within the range of normality for all subjects and all parameters, except for the following:
ratio of residual volume to total lung capacity; expiratory reserve volume; and the alveolar-arterial oxygen gradient. The subjects with
dyspnea presented significantly lower values for expiratory reserve volume, maximal expiratory pressure and arterial pH. In all subjects, body
mass index correlated significantly with the following: baseline dyspnea index; the residual volume/total lung capacity ratio; the forced
expiratory volume in one second/forced vital capacity ratio; forced expiratory flow between 25% and 75% of forced vital capacity; arterial
oxygen tension; the alveolar-arterial oxygen gradient; and arterial carbon dioxide tension. The baseline dyspnea index was found to correlate
significantly with the following parameters: residual volume/total lung capacity ratio; expiratory reserve volume; arterial oxygen tension;
the alveolar-arterial oxygen gradient; and arterial carbon dioxide tension. Conclusion: Dyspnea is a common complaint in individuals with
class II or III obesity. Such individuals present a pronounced reduction in expiratory reserve volume and an increase in the alveolar-arterial
oxygen gradient. The correlations found suggest that obese individuals present dysfunction of the lower airways, and that obesity itself plays
a role in the genesis of dyspnea.
Keywords: Obesity/complications; Dyspnea/epidemiology; Dyspnea/physiopathology; Respiratory function tests