![]() Fifty four participants with productive lung disorders (cystic fibrosis and bronchiectasis) were recruited from out-patient clinics. Two experimental studies were conducted incorporating ‘before-and-after’ and ‘repeated measures’ components. In this research, Computer Aided Lung Sound Analysis (CALSA) was used to assess whether adventitious lung sounds’ characteristics could be quantified clinically and used as a new objective, non-invasive, bedside clinical outcome measure for physiotherapy alveolar recruitment and airway clearance techniques. However, standard auscultation techniques are too subjective to allow them to be used as an outcome measure. Lung sounds provide useful, specific information for assessing and monitoring respiratory patients. This previously unrecognized behavior of lung sounds over short distances might reflect spatial variations of airways and diaphragms during breathing.Ī barrier to assessing the effectiveness of respiratory physiotherapy has been insufficient accurate, reliable and sensitive outcome measures. During inspiration, increasing delay and amplitude of sound at the caudal relative to the cranial sensor were also observed during passive transmission in several subjects. Volume-dependent variations in phase (≤1.5 ms) and amplitude (≤11 dB) were observed at the lower lobes in the 150- to 300-Hz band. Cross correlation established the phase relation of sound between sensors. Average sound amplitudes were obtained after band-pass filtering to 75–150, 150–300, and 300–600 Hz. Lung sounds were recorded at the posterior right upper, right lower, and left lower lobes during targeted breathing (1.2 ± 0.2 l/s volume = 20–50 and 50–80% of vital capacity) and passive sound transmission (≤0.2 l/s volumes as above). ![]() We investigated volume-dependent variations of lung sound phase and amplitude between two closely spaced sensors in five adults. Acute lung injury increases the power of breath sounds likely secondary to redistribution of ventilation from collapsed to aerated parts of the lung and improved sound transmission in dependent, consolidated areas.Īcoustic imaging of the respiratory system demonstrates regional changes of lung sounds that correspond to pulmonary ventilation. The deterioration in gas exchange and lung mechanics correlated best with concurrent spectral changes in the nondependent lung regions. A concomitant increase in sound power was seen in all lung regions ( P < 0.05), predominantly in frequencies 150–800 Hz. Oleic acid injections rapidly produced severe derangements in the gas exchange and mechanical properties of the lung, with an average increase in venous admixture from 16 ± 12 to 62 ± 16% ( P < 0.01), and a reduction in dynamic respiratory system compliance from 25 ± 4 to 14 ± 4 ml/cmH2O ( P < 0.01). To evaluate the effect of acute lung injury on the frequency spectra of breath sounds, we made serial acoustic recordings from nondependent, midlung and dependent regions of both lungs in ten 35- to 45-kg anesthetized, intubated, and mechanically ventilated pigs during development of acute lung injury induced with intravenous oleic acid in prone or supine position. Increased lead and lag times in COPD patients are consistent with the phenomenon of pendelluft as has been observed by other methods. Both lead and lag correlated moderately with the GOLD stage (correlation coefficient 0.43).Conclusion. When normalized by the duration of the inspiration at the trachea, the lead was14☑3% for COPD versus4±5% for controls (P<0.0001). The lag time was also significantly longer in COPD patients:269☒49 ms in COPD patients versus147☑24 ms in controls (P<0.0001). The lead time was significantly longer in COPD patients:123☑07 ms versus48±59 ms in controls (P<0.0001). ![]() ![]() These lead and lag times were calculated for the 14 chest wall sites.Results. Pendelluft at the end of inspiration is expected to result in vesicular sounds lagging the tracheal sound. Pendelluft at the beginning of inspiration is expected to result in vesicular sounds leading the tracheal sound by a few milliseconds. A 16-channel lung sound analyzer was used to collect sounds from patients with COPD (n=90) and age-matched normals (n=90). The objective of this study was to apply the method of lung sounds mapping, which is known to provide regional information about gas flow, to study pendelluft in COPD patients.Methods. Gas moves in the opposite direction at the end of inspiration. In patients with regional variations in resistance and elastance, gas moves at the beginning of inspiration out of some alveoli into others. The phenomenon of pendelluft was described over five decades ago.
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