Protective effect of bronchial challenge with hypertonic saline on nocturnal asthma
Braz. j. med. biol. res
; 41(3): 209-214, Mar. 2008. ilus, tab
Article
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| LILACS
| ID: lil-476578
Biblioteca responsable:
BR1.1
ABSTRACT
Inhalation of hypertonic saline (HS) causes bronchoconstriction in asthmatic subjects. Repeated inhalation of HS leads to substantially reduced bronchoconstriction, known as the refractory period. Refractoriness due to different stimuli has also been described (cross-refractoriness). Nocturnal asthma is defined as an increase in symptoms, need for medication, airway responsiveness, and/or worsening of lung function that usually occurs from 4 to 6 am. Our objective was to determine the effect of refractoriness on nocturnal asthma. The challenge test consisted of inhalations of 4.5 percent saline with increasing durations until a reduction of 20 percent in forced expiratory volume in 1 s (FEV1) (PD20HS) or total time of 15.5 min. Twelve subjects with nocturnal asthma were challenged with HS at 1600 and 1800 h and FEV1 was measured at 400 h. One to 2 weeks later, FEV1 was determined at 1600 and 400 h. LogPD20HS at 1800 h was significantly greater than logPD20HS at 1600 h, 0.51 ± 0.50 and 0.69 ± 0.60 mg, respectively (P = 0.0033). When subjects underwent two HS challenges in the afternoon, mean (± SD) FEV1 reduction was 206 ± 414 mL or 9.81 ± 17.42 percent. On the control day (without challenge in the afternoon) FEV1 reduction was 523 ± 308 mL or 22.75 ± 15.40 percent (P = 0.021). Baseline FEV1 values did not differ significantly between the control and study days, 2.48 ± 0.62 and 2.36 ± 0.46 L, respectively. The refractory period following HS challenges reduces the nocturnal worsening of asthma. This new concept may provide beneficial applications to asthmatic patients.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
LILACS
Asunto principal:
Asma
/
Solución Salina Hipertónica
/
Pruebas de Provocación Bronquial
Límite:
Adult
/
Female
/
Humans
/
Male
Idioma:
En
Revista:
Braz. j. med. biol. res
Asunto de la revista:
BIOLOGIA
/
MEDICINA
Año:
2008
Tipo del documento:
Article
País de afiliación:
Brasil
Pais de publicación:
Brasil