Measurements and theory of normal tracheal breath sounds.

We studied the mechanisms by which turbulent flow induces tracheal wall vibrations detected as tracheal breath sounds (TRBSs). The effects of flow rate at transitional Reynold's numbers (1300-10,000) and gas density on spectral patterns of TRBSs in eight normal subjects were measured. TRBSs were recorded with a contact sensor during air and heliox breathing at four flow rates (1.

Airflow effects on amplitude and spectral content of normal breath sounds.

Even though it is well known that breath-sound amplitude (BSA) increases with airflow, the exact quantitative relationships and their distribution within the relevant frequency range have not yet been determined. To evaluate these relationships, the spectral content of tracheal and chest wall breath sounds was measured during breath hold, inspiration, and expiration in six normal men. Average spectra were measured at six flow rates from 0.

Spectral characteristics of chest wall breath sounds in normal subjects.

Background: This study was carried out to establish a reliable bank of information on the spectral characteristics of chest wall breath sounds from healthy men and women, both non-smokers and smokers.

Methods: Chest wall breath sounds from 272 men and 81 women were measured using contact acoustic sensors, amplifiers, and fast Fourier transform (FFT) based spectral analysis software. Inspiratory and expiratory sounds were picked up at three standard locations on the chest wall during breathing at flows of 1-2 l/s and analysed breath by breath in real time.

COPD in the elderly. A reversible cause of functional impairment.

Objectives: To determine the frequency of referral of patients age 69 years and older to the pulmonary function laboratory at a tertiary-care hospital for airflow limitation studies; to determine the point prevalence of a significant reversible component in patients with COPD as an age-related function; and to determine the proportion of patients who were prescribed bronchodilators following a pulmonary function test (PFT) demonstrating significant reversibility.

Design: A retrospective review of pulmonary function tests of patients 69 years and older within calendar year 1990 was performed. Chart review of those showing significant reversibility to bronchodilators during a PFT was performed to determine level of follow-up.