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
Artículo
en Español
| 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 andmethods:
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:
Disponible
Índice:
LILACS (Américas)
Asunto principal:
Espirometría
/
Ruidos Respiratorios
/
Diagnóstico por Computador
/
Enfermedades Pulmonares Obstructivas
Tipo de estudio:
Estudio diagnóstico
Límite:
Child, preschool
/
Femenino
/
Humanos
/
Masculino
Idioma:
Español
Revista:
Rev. méd. Chile
Asunto de la revista:
Medicina
Año:
2001
Tipo del documento:
Artículo
/
Documento de proyecto
País de afiliación:
Chile
Institución/País de afiliación:
Pontificia Universidad Católica de Chile/CL
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