NEONATAL SOCIETY ABSTRACTS
Computerised breath sounds analysis in term and preterm infants
Presented at the Neonatal Society 2002 Summer Meeting (programme).
Majumdar A, Elphick HE, Shaw NJ
Liverpool Regional Neonatal Unit, Crown Street, Liverpool L8 7SS, UK
Background and aims: Computerized breath sounds analysis provides a non-invasive method for objective assessment of lung sounds in infants. This pilot study aimed to investigate the normal breath sounds of term and preterm infants.
Methods: Respiratory sounds were recorded using a contact sensor placed over the right upper zone of the infant's chest, anteriorly. Air flow at the mouth was simultaneously recorded using a pneumotachograph. The recording on each occasion lasted for one minute of tidal breathing, with the baby quiet or asleep. Specialized equipment for sound recording and analysis was used (RALE: Respiratory Acoustics Laboratory Environment). The sound was analyzed using a Fast Fourier Transformation technique. At inspiratory flow rates of 0.1 +/-20% l/sec/kg, recordings were analyzed for each infant. The slope of the straight part of the plot of the log frequency against log intensity was calculated, as a measure of the overall breath sounds intensity.
Results: Breath sounds intensity was higher at the same frequency in preterm infants compared to term infants and this was associated with gestational age (R2=0.19). The average slope of the log frequency - log intensity distribution, was -3.4 in term infants and -3.8 in preterm infants (p<0.05).
Conclusions: Breath sounds intensity (loudness) was found to be higher in preterm compared to term infants. This may reflect that the relative size of the airways and the relative depth of chest wall cavity are important factors in determining breath sounds intensity. These data may provide a normal reference in order to study further neonates requiring oxygen and with chronic lung disease.
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