Resumen

SANCHEZ D, Ignacio; VIZCAYA A, Cecilia  y  GARCIA P, Daniela. Breath sound analysis and wheezing in cystic fiposis. Rev. chil. pediatr. [online]. 2003, vol.74, n.6, pp.590-594. ISSN 0370-4106.  http://dx.doi.org/10.4067/S0370-41062003000600005.

Wheezes are musical sounds caused by obstructed airways and depend on airflow, a critical pressure and a geometrical airway distortion. Objective to characterize wheezing and the lung sound spectra in cystic fiposis (CF). Patient and Methods: 14 patients (8 boys), aged 14.± 2 years, 6 children had DF508/DF508 mutation. Subjects peathed through a pneumotachograph at flows of 0.5 ± 0.05 l/s. Respiratory sounds were recorded using contact sensors on the supra-sternal notch and on the thoracic region corresponding to the right lower lobe. Sound signals were low-pass filtered, amplified and Fourier analisis was applied to sounds within the target flow range. From averaged spectra, power at low (100-200 Hz = P₁) and high frequencies (400-2 000Hz = P₂) were calculated. We measured the frequencies below in which 50% (F50) and 99% (SEF99) of the spectral power between 100-2 000 Hz were contained. After baseline recording, patients received inhaled salbutamol (200 mcg) and 15 minutes later the measurements were repeated. Results:Baseline spirometry was FVC ± 15%, FEV₁44 ± 12%, FEF₂₅-₇₅: 40 ± 14% and SaO₂93.4 ± 2%. Only in 6/14 patients we obtained a sinusoidal waveform of a typical wheeze, the others had complex waveforms. There was a significant increase in P₁and decrease in P₂during inspiration after salbutamol (p < 0.001) with a significant correlation between FEV₁vs F50 and SEF99 (p < 0.01). Conclusion:Our results show that CF patients have both complex and classical wheezes and that the sound spectral analysis correlates with lung function. Lung sounds analysis is a useful method to study ponchial obstruction mechanisms in CF patients

Palabras clave : Cystic fiposis; spectral analysis; wheeze; salbutamol response.