Distinguishable Sensations of Breathlessness Induced in Normal Volunteers

Abstract

Various theories about the genesis of dyspnea have often assumed that the sensation is similar from patient to patient and is generated by a single underlying mechanism. To investigate whether breathlessness induced in normal volunteers by different stimuli represents one or more than one sensation, we studied 30 subjects in whom breathlessness was induced by each of 8 different stimuli: breath-holding, CO2 inhalation, inhalation of CO2, with ventilation voluntarily targeted below the level dictated by chemical drive, breathing with a resistive load, breathing with an elastic load, voluntary elevation of functional residual capacity, voluntary limitation of tidal volume, and exercise. For each stimulus, subjects were asked to choose description of their sensation(s) of breathlessness from a questionnaire listing 19 descriptors. The responses from this questionnaire were evaluated using cluster analysis to search for relationships among descriptors and to identify natural groupings. We found that distinct groups of descriptors emerged, i.e., subjects could distinguish different sensations of breathlessness. In addition, we found an association between certain descriptor groups and stimuli. We conclude that the term breathlessness may encompass multiple sensations, and, therefore, may not be explainable by a single physiologic mechanism.

Oxygen for relief of dyspnoea in mildly- or non-hypoxaemic patients with cancer: a systematic review and meta-analysis

“…Defined by the American Thoracic Society as 'a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity', dyspnoea is a very personal experience (ATS, 1999). Descriptions vary widely; examples include 'short of breath', 'hard to move air', 'chest tightness', 'choking', 'panting', and 'gasping' (Brown et al, 1986;Simon et al, 1989;Roberts et al, 1993;Harver et al, 2000). The experience of dyspnoea can be affected by many conditions, including the cancer itself, coexisting diseases, and cancer cachexia (Reuben and Mor, 1986;Ripamonti, 1999;Bruera et al, 2000).…”

Uso de descritores de dispneia desenvolvidos no Brasil em pacientes com doenças cardiorrespiratórias ou obesidade

“…(6)(7)(8)(9) Figure 1 -Dendrogram illustrating the distribution of dyspnea descriptors and clusters formed after 180 volunteers had selected the three descriptors that best described their sensation of dyspnea. criterion on which to base the decision depends on the point of view and judgment of authors.…”

“…For instance, in a study of healthy volunteers submitted to eight distinct respiratory stimuli, such as carbon dioxide inhalation, breathing against elastic load, and physical exercise, the authors identified clusters of descriptive terms applied to the respiratory sensations; those clusters were associated with the different agents employed. (6) In another study, involving 218 patients presenting with seven distinct cardiorespiratory conditions in the stable phase, the use of a questionnaire including 15 descriptive questions regarding their respiratory sensations revealed clusters of descriptors, the combinations of which were specific to each diagnosis. (9) Although there have been many studies regarding the potential use of descriptive terms applied to the sensation of dyspnea (dyspnea descriptors), (11)(12)(13)(14)(15)(16) there is a lack of such studies in Brazil.…”

“…(5) There is mounting evidence that dyspnea does not involve a single, specific perception; rather, it involves a set of distinct sensations. (6)(7)(8)(9)(10) As has been observed for pain, different terms used by patients to describe the sensation of dyspnea might reflect the underlying pathophysiological mechanisms and therefore be related to the underlying diagnoses. For instance, in a study of healthy volunteers submitted to eight distinct respiratory stimuli, such as carbon dioxide inhalation, breathing against elastic load, and physical exercise, the authors identified clusters of descriptive terms applied to the respiratory sensations; those clusters were associated with the different agents employed.…”

“…(6,9) Initially, the number of times that the descriptors within a given cluster were chosen as the 3 best was divided by the product of the number of descriptors within that cluster and the number of patients with that specific condition. If the result was > 0.25, the cluster of descriptors was considered representative of the disease.…”