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

Objective: To investigate the usefulness of descriptive terms applied to the sensation of dyspnea (dyspnea descriptors) that were developed in English and translated to Brazilian Portuguese in patients with four distinct clinical conditions that can be accompanied by dyspnea. Methods: We translated, from English to Brazilian Portuguese, a list of 15 dyspnea descriptors reported in a study conducted in the USA. Those 15 descriptors were applied in 50 asthma patients, 50 COPD patients, 30 patients with heart failure, and 50 patients with class II or III obesity. The three best descriptors, as selected by the patients, were studied by cluster analysis. Potential associations between the identified clusters and the four clinical conditions were also investigated. Results: The use of this set of descriptors led to a solution with nine clusters, designated expiração (exhalation), fome de ar (air hunger), sufoco (suffocating), superficial (shallow), rápido (rapid), aperto (tight), falta de ar (shortness of breath), trabalho (work), and inspiração (inhalation). Overlapping of the descriptors was quite common among the patients, regardless of their clinical condition. Asthma, COPD, and heart failure were significantly associated with the inspiração cluster. Heart failure was also associated with the trabalho cluster, whereas obesity was not associated with any of the clusters. Conclusions: In our study sample, the application of dyspnea descriptors translated from English to Portuguese led to the identification of distinct clusters, some of which were similar to those identified in a study conducted in the USA. The translated descriptors were less useful than were those developed in Brazil regarding their ability to generate significant associations among the clinical conditions investigated here.

Keywords: Dyspnea; Pulmonary disease, chronic obstructive; Asthma; Heart failure.

Objective: To develop a set of descriptive terms applied to the sensation of dyspnea (dyspnea descriptors) for use in Brazil and to investigate the usefulness of these descriptors in four distinct clinical conditions that can be accompanied by dyspnea. Methods: We collected 111 dyspnea descriptors from 67 patients and 10 health professionals. These descriptors were analyzed and reduced to 15 based on their frequency of use, similarity of meaning, and potential pathophysiological value. Those 15 descriptors were applied in 50 asthma patients, 50 COPD patients, 30 patients with heart failure, and 50 patients with class II or III obesity. The three best descriptors, as selected by the patients, were studied by cluster analysis. Potential associations between the identified clusters and the four clinical conditions were also investigated. Results: The use of this set of descriptors led to a solution with seven clusters, designated sufoco (suffocating), aperto (tight), rápido (rapid), fadiga (fatigue), abafado (stuffy), trabalho/inspiração (work/inhalation), and falta de ar (shortness of breath). Overlapping of descriptors was quite common among the patients, regardless of their clinical condition. Asthma was significantly associated with the sufoco and trabalho/inspiração clusters, whereas COPD and heart failure were associated with the sufoco, trabalho/inspiração, and falta de ar clusters. Obesity was associated only with the falta de ar cluster. Conclusions: In Brazil, patients who are accustomed to perceiving dyspnea employ various descriptors in order to describe the symptom, and these descriptors can be grouped into similar clusters. In our study sample, such clusters showed no usefulness in differentiating among the four clinical conditions evaluated.

Keywords: Dyspnea; Pulmonary disease, chronic obstructive; Asthma; Heart failure.