Breath-holding test in subjects with near-fatal asthma. A new index for dyspnea perception.
BACKGROUND
Identification of asthmatic subjects with low perception of dyspnea (POD) that are at higher risk of hospitalization, near-fatal and fatal asthma could improve their management.


OBJECTIVE
Create a simple procedure that facilitate the recognition of low POD.


METHODS
We enrolled near fatal asthma (NFA) subjects and a wide spectrum of non-NFA subjects. Each subject was asked to stop breathing at end-expiration. Dyspnea was assesssed by a modified Borg scale. To design the new index, we combined the Borg score at the end of the voluntary breath-holding maneuver with the airway limitation. The equation was as follows: FEV(1)/FVC%/(breath-holding time in seconds/final Borg score minus basal Borg score).


RESULTS
Eleven NFA subjects (4 females) aged 21-73yr and 55 non-NFA (14 severe, 18 moderate and 23 mild asthmatic subjects) completed the study. The threshold value of the index that could predict POD is <12. The mean (+/-sd) of the new index perception was significantly lower in NFA group (n=11; 5.21+/-3.59; vs. n=55; 13.67+/-11.08; P=0.006). This threshold value had 100% sensitivity and it best discriminated between mild and NFA groups. The negative likelihood ratio (when the index > or = 12) was zero. A result > or = 12 represented an almost null probability of poor POD.


CONCLUSIONS
The breath-holding test is simple and rapid. Its negative likelihood ratio was zero. Accordingly, a test result of 12 or greater might exclude the probability of poor perception of dyspnea in subjects with stable asthma.
Nannini
L J
LJ
Servicio de Neumonología, Hospital de G Baigorria, Facultad de Medicina, Universidad Nacional de Rosario, Argentina. nanninilj@cimero.org.ar
Zaietta
G A
GA
Guerrera
A J
AJ
Varela
J A
JA
Fernández
O M
OM
Flores
D M
DM
D000328:Adult; D000368:Aged; D001249:Asthma / Q000150:complications / Q000503:physiopathology* / Q000523:psychology; D001944:Breath Tests / Q000379:methods; D004417:Dyspnea / Q000150:complications / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010465:Perception / Q000502:physiology*; D012720:Severity of Illness Index; D014797:Vital Capacity / Q000502:physiology