[Asthma control. Possible obstacles along the way]

With current therapeutic regimens, asthma should be well controlled in most patients. However, although asthma-related hospital admissions and mortality have decreased, the potential efficacy of treatments is not translating into optimal asthma control and quality of life. This discrepancy may be due to several factors and is complex to analyze. Poor asthma control can be caused by diverse reasons such as the patient's failure to understand how to take the medication, the presence of an untreated, underlying comorbid condition that aggravates the asthma, and the possibility that the patient has a severe form of glucocorticosteroid-insensitive asthma. The present article reviews the situations in which poor asthma control occurs for human-related reasons. These situations can be due to patients themselves and be independent of the disease or can be due to inadequate intervention by health professionals in specific areas and circumstances linked to asthma. A small but important group of patients with asthma is also analyzed; in this group, the asthma per se is severe and is refractory to routine treatments.

[Descriptors of breathlessness in Mexican Spanish]

OBJECTIVE

Breathlessness is the most common symptom of cardiovascular or pulmonary disease. The term encompasses a wide range of descriptors used by patients, however. Identifying those descriptors can be useful for analyzing symptoms and understanding how they arise. The aim of this study was to characterize the descriptors of breathlessness used in Mexican Spanish and to consider their association with various states of respiratory distress and cardiovascular or pulmonary disease.

MATERIAL AND METHODS

A questionnaire was based on 21 descriptors of breathlessness, some of which had no equivalents in English. The subjects included 15 healthy individuals during a cardiopulmonary stress test, 13 healthy subjects after a carbon dioxide rebreathing procedure, and 10 healthy women during pregnancy. We also included 16 patients with confirmed heart disease in stable condition, 15 patients during exacerbation of asthma, 20 with stable chronic obstructive pulmonary disease, and 15 with diffuse interstitial lung disease also in stable condition. Descriptors of breathlessness were then grouped based on the results of cluster analysis.

RESULTS

Seven clusters of phrasal descriptors were identified as possibly representative of types of dyspnea. These clusters of descriptors were categorized as follows: agitation, suffocation, smothering, inhalation, exhalation, panting, and rapidity. Associations between types of dyspnea and the groups of participants were identified based on how frequently they used the terms.

CONCLUSIONS

At least 7 clusters or groups of descriptors of breathlessness were identified as equivalent to 7 types of dyspnea; some items have no equivalent in English. Healthy subjects with respiratory distress or certain groups of patients with cardiovascular or pulmonary disease are associated with certain types of dyspnea.

[Evolution over time in over perceivers of dyspnea in asthma]

OBJECTIVE

In previous studies we identified a subgroup of patients whose perception of breathlessness was exaggerated during acute bronchoconstriction and who were termed "over perceivers" or "hyperperceivers". In this study we aimed to determine whether such over perception is sporadic or stable over time. We also examined whether there is an association between over perception of dyspnea and hyperventilation syndrome.

PATIENTS AND METHODS

The subjects were 22 stable asthmatics (11 men, 11 women) who had been over perceivers of dyspnea in a study 9 years earlier. After a medical history was taken, a patient performed forced spirometry and a severity classification was made according to the criteria of the Global Initiative for Asthma (GINA). A bronchial histamine challenge was then administered to measure dose-related perception of dyspnea on a Borg scale, according to a procedure that was similar to the one used 9 years earlier by the same investigator. The patients were also asked for a subjective assessment of the severity of their asthma (scale, 0-10) and to respond to items on the Nijmegen hyperventilation questionnaire and the trait form of the State-Trait Anxiety Inventory.

RESULTS

The overall perception of severity of disease, level of anxiety, and perception of dyspnea at rest were lower after 9 years (P<.001). No change was observed in bronchial hyperresponsiveness (dose of inhaled histamine required to provoke a 20% decline in forced expiratory volume in the first second [FEV1]-PD20) or objective parameters of severity (FEV1 and GINA classification). Fourteen asthmatics (64%) were still over perceivers and the other patients had changed: 6 were normal perceivers and 2 were "poor perceivers". Only subjective perception of disease severity improved for the patients who were still over perceivers; the other patients, on the other hand, showed improvements in subjective assessments, objective ones (except PD20), and anxiety. Finally, those who remained over perceivers had higher scores for anxiety (24 vs 15; P<.05) and hyperventilation (18 vs 13; P= not significant).

CONCLUSIONS

Most over perceivers of dyspnea remain so over the years and this trait is related to anxiety. We have been unable to demonstrate an association with hyperventilation syndrome.

[Does experience influence perception of dyspnea?]

OBJECTIVE

The perception of somatic sensations like dyspnea can be influenced by such factors as an individual s personality, experiences, or ability to adapt to stimuli. Our aim was to determine whether the perception of acute bronchoconstriction is different for patients with asthma and patients who have never experienced an episode of airway obstruction.

PATIENTS AND METHOD

We studied 2 groups of patients. The first consisted of 24 subjects with intermittent rhinitis and asthma (10 females and 14 males) with a mean (SD) age of 25 (7) years. All reported not feeling dyspnea at rest on a Borg scale. The second group consisted of 24 subjects who only had rhinitis but no lung disease (no episode of asthma) or dyspnea at rest (12 females and 12 males) with a mean age of 27 (6) years. There were no significant differences between the groups with regard to sex, smoking, economic or educational level, anxiety (determined by the trait portion of the State-Trait Anxiety Inventory), depression (Beck Depression Inventory), or spirometric parameters. All took a histamine bronchial provocation test in which the patient assessed dyspnea on a modified Borg scale after each histamine dose. The provocation dose needed to produce a 20% decrease (PD20) in forced expiratory volume in the first second (FEV1) was calculated. We also recorded dyspnea perception score when FEV1 fell 5%, 10%, 15%, and 20%.

RESULTS

No dyspnea was perceived at PS20 by 12.5% of the asthmatics and by 45% of nonasthmatics (P< .0001). The mean PS20 was 2.4 (2.1) (range, 0-7) in the first group and 0.37 (0.48) (range, 0-3) in the second (P< .0001). More asthma patients than nonasthmatics perceived dyspnea at all degrees of bronchial obstruction. PD20 was different in the 2 groups (1.6 [2] vs 6.03 [5] for the first and second groups, respectively; P< .003), but there was no significant relation between PD20 and PS20 (Spearman s correlation coefficient, 0.19; P= .221).

CONCLUSION

Our findings support the hypothesis that appropriate perception of dyspnea is grounded in prior experience and learning.