Análisis computacional de los ruidos respiratorios en la evaluación de la obstrucción bronquial en niños pequeños que no colaboran con las pruebas espirométricas / Acoustic analysis of respiratory sounds during methacholine challenge in preschool children
Rev. méd. Chile
;
129(11): 1271-1278, nov. 2001. tab, graf
Artigo
em Espanhol
| LILACS
| ID: lil-302633
ABSTRACT
Background: There are changes in inspiratory breath sound intensity in patients with airway obstruction. Airway narrowing may change sound spectral characteristics. Aim: To define the characteristics of lung sounds at standardized air flow during methacholine challenge and to compare acoustic changes with transcutaneous oxygen tension (PtcO2) during induced airway narrowing. Patients and methods: Forty asthmatic children (20 male) aged 5.2ñ1 years and 40 normal children (18 male), aged 5.6 ñ 1 years were studied. All patients were free of respiratory tract infections one month before the study. A methacholine challenge from 0.06 to 8 mg/ml was performed; the test was ended when a fall in PtcO2 of >20 percent from baseline was observed or if the final concentration was reached. Subjects breathed through a pneumotachograph aiming at flows of 0.4 to 0.6 l/s. Respiratory sounds were recorded using contact sensors at the suprasternal notch and at the posterior right lower lobe. From average spectra, power at low (100-200 Hz=P1) and high frequencies (400-2000 =P2) was calculated. Frequencies below which 50 percent (F50) and 99 percent (SEF90) of the spectral power between 100 and 2000 Hz was contained, were also calculated. Results: In asthmatics, the metacholine concentration at which a 20 percent fall in PtcO2 was observed, was lower than in normal children (p< 0.05). There was an increase in P1 (p<0.01) and a reduction in P2 (p<0.01) during inspiration, in subjects that experienced a 20 percent reduction in PtcO2. Also, there was an increase in F50 and SEF99 during inspiration in lung sounds, but not over the trachea. Conclusions: Lung sounds analysis can be useful for the assessment of airway reactivity in asthmatic children
Texto completo:
DisponíveL
Índice:
LILACS (Américas)
Assunto principal:
Espirometria
/
Sons Respiratórios
/
Diagnóstico por Computador
/
Pneumopatias Obstrutivas
Tipo de estudo:
Estudo diagnóstico
Limite:
Criança, pré-escolar
/
Feminino
/
Humanos
/
Masculino
Idioma:
Espanhol
Revista:
Rev. méd. Chile
Assunto da revista:
Medicina
Ano de publicação:
2001
Tipo de documento:
Artigo
/
Documento de projeto
País de afiliação:
Chile
Instituição/País de afiliação:
Pontificia Universidad Católica de Chile/CL
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