Control of ventilation, breathlessness perception and alexithymia in near-fatal asthma.

Several studies have demonstrated impaired control of ventilation in some patients with near-fatal asthma (NFA). The objective of our study was to determine a possible relationship between alexithymia (a cognitive processing disorder), control of ventilation, and breathlessness perception in patients who had an NFA attack. We analyzed data from 100 subjects: 50 with NFA, 25 asthmatics without NFA, and 25 non-asthmatic controls. Ventilatory responses to hypoxia and hypercapnia were measured by the rebreathing technique in terms of slope of ventilation and mouth occlusion pressure (P0.1). Breathlessness perception was assessed with the Borg scale and alexithymia with the Toronto Alexithymia Scale (TAS). No statistical differences were observed between groups in breathlessness perception and ventilatory responses. The mean (SD) TAS score of 63.6 (14.9) in the NFA group was significantly higher than the score of 56.4 (12.1) in the non-asthmatic group (p = 0.007). More subjects with alexithymia were identified in the NFA group (24%) than in the non-NFA group (12%) or the non-asthmatic control group (12%). Although the presence of alexithymia did not correlate with poor ventilatory responses or breathlessness perception, it was associated with a larger number of previous hospitalisations: 6.2 (8.1) in the NFA group and 2.8 (4.8) in the non-NFA group (p = 0.036). In conclusion, the prevalence of alexithymia is higher among NFA patients than among asthmatics who have not experienced NFA attacks. Neither altered breathlessness perception nor ventilatory response to hypoxia seems to play a role in NFA, although alexithymia may favor poor clinical control.