Significance of Spectral and Time Parameters of Forced Expiratory Sound in Evaluating Bronchial Patency

Spectral and time characteristics of forced expiratory sound, recorded in the trachea, were analyzed in 96 subjects. Sick and healthy subjects and the risk group demonstrated substantial differences in the acoustic parameters (total sound duration, vortex stoppage duration, and emergence of spectral components with high frequency and narrow band at the end of an expiration). The authors suggest and substantiate acoustic criteria of the bronchial patency disorder, assuming on this basis that such disorders are more common in patients with chronic nonobstructive bronchitis (70.8%) and subjects at risk for chronic obstructive pulmonary diseases (45.4%) than is demonstrated by conventional functional methods.     

Regression simulation of the dependence of forced expiratory tracheal noises duration on human respiratory system biomechanical parameters

BACKGROUND: Estimating the duration of forced exhalation tracheal noises shows promise for recognizing bronchial obstruction. OBJECTIVE: Experimental simulation of an influence of biomechanical parameters on the duration of normal forced exhalation tracheal noises. METHOD AND MATERIALS: Thirty-two healthy non-smoking men aged 16-22 years were examined. The duration of noises, the parameters of computer spirometry, and the maximum static expiratory pressure are recorded. These data were analyzed by means of multiple linear regression simulation for logarithms of the elements of the proportionality relation obtained with the use of a one-component biomechanical model of forced exhalation and a linearized approximation of flow-volume curve. RESULTS: Dependence between duration of the forced expiratory noises recorded on human trachea and the product of forced volume capacity (in power of 1.05 +/- 0.27), maximum static expiratory pressure (in power of 0.46 +/- 0.23), equivalent expiratory resistance in the stage of functional expiratory stenosis (in power of 0.72 +/- 0.15 in healthy is an estimate of the equivalent expiratory resistance of human bronchial tree in the functional expiratory stenosis phase, whereas in patients with bronchial obstruction it is supposed to take into account an excess of noise generation time compared with the time predicted from normal individual value of this resistance.     

Spectra of the voluntary first cough sounds

The voluntary cough sounds recorded according to Korpas and Sadlonova-Korpasova were sampled at a frequency of 20.000Hz and spectra of six consecutive windows of 50ms were estimated. To digitize signals an autotrigger mode was used. The subjects were healthy volunteers as well as patients with chronic bronchitis, asthma, bronchial carcinoma (growing intraluminarly in the 1st or in the 2nd or in the 3rd order bronchi), emphysema, laryngeal nerve paralyzis or laryngotomy. The duration of averaged cough sounds of patients was longer than that of healthy volunteers. The mean power of the spectra in the successive windows showed different patterns in the same group. In the third window of healthy volunteers (0.10 s-0.15 s) a high modulus broad bandwidth (between 1-2 kHz) spectrum was found which was considered as a bronchial "flute", and was probably related to the lowest resistance as well as to the velocity of airflow of cough manoeuvre. This pattern appeared with a delay and/or it was changed in the diseased groups compared to the healthy volunteers. Due to this delay, the spectra of the fifth window (0.20 s-0.25 s) showed somewhat higher harmonics (400-800 Hz) in the patients with chronic obstructive pulmonary diseases (COPD), carcinoma and laryngeal nerve paralyzis than in healthy volunteers. In emphysematous patients in the first (0.00-0.05 s), in the third (0.10-0.15 s) and in the fifth (0.20-0.25 s) windows the fundamental frequency was low (156-176 Hz) compared to that of the other groups. The paralyzed vocal cords functioning as an added resistance to the expiratory effort caused a phase-shift in the cough patterns, similarly to that seen in COPD patients. Due to the cannula, the spectra of patients having laryngotomy had a lot of high harmonics. They also had peaks nearly identical to that of bronchitic patients because they suffered from serious chronic bronchitis. It was found that by examination the cough spectra of series of voluntary cough sound signals it was possible to distinguish healthy volunteers from patients. This examination would therefore be useful for screening of bronchial diseases.     

Selected contribution: airway caliber in healthy and asthmatic subjects: effects of bronchial challenge and deep inspirations.

In 9 healthy and 14 asthmatic subjects before and after a standard bronchial challenge and a modified [deep inspiration (DI), inhibited] bronchial challenge and after albuterol, we tracked airway caliber by synthesizing a method to measure airway resistance (Raw; i.e., lung resistance at 8 Hz) in real time. We determined the minimum Raw achievable during a DI to total lung capacity and the subsequent dynamics of Raw after exhalation and resumption of tidal breathing. Results showed that even after a bronchial challenge healthy subjects can dilate airways maximally, and the dilation caused by a single DI takes several breaths to return to baseline. In contrast, at baseline, asthmatic subjects cannot maximally dilate their airways, and this worsens considerably postconstriction. Moreover, after a DI, the dilation that does occur in airway caliber in asthmatic subjects constricts back to baseline much faster (often after a single breath). After albuterol, asthmatic subjects could dilate airways much closer to levels of those of healthy subjects. These data suggest that the asthmatic smooth muscle resides in a stiffer biological state compared with the stimulated healthy smooth muscle, and inhibiting a DI in healthy subjects cannot mimic this.     

Induction of drug-metabolizing enzymes and transporters in human bronchial epithelial cells by beclomethasone dipropionate

Inhaled steroids are the most potent anti-inflammatory therapy commonly used in bronchial asthma. There are, however, a small number of asthmatic patients who do not respond to inhaled steroid-treatment. The stimulation of metabolism and excretion of inhaled drugs at bronchial tissues might lead to a decrease in the effect of the drugs, although the molecular mechanism of this resistance is unclear. In this study, we found that beclomethasone dipropionate (BDP) stimulated the expression of mRNAs for uridine 5'-diphosphate glucuronosyl transferase 2B4 and 2B11, and transporters such as multidrug resistance P-glycoprotein, multidrug resistance-associated protein 1 and 2 in cultured bronchial epithelial cells. It is possible that the individual differences of expression of drug metabolizing enzymes and transporters and their enhancement with BDP are implicated in the individual differences of reactivity over steroid medical treatment.     

Signal Transduction in Smooth Muscle: Selected Contribution: Airway caliber in healthy and asthmatic subjects: effects of bronchial challenge and deep inspirations

In 9 healthy and 14 asthmatic subjects before and after astandard bronchial challenge and a modified [deep inspiration (DI), inhibited] bronchial challenge and after albuterol, we tracked airwaycaliber by synthesizing a method to measure airway resistance (Raw;i.e., lung resistance at 8 Hz) in real time. We determined the minimumRaw achievable during a DI to total lung capacity and the subsequentdynamics of Raw after exhalation and resumption of tidal breathing.Results showed that even after a bronchial challenge healthy subjectscan dilate airways maximally, and the dilation caused by a single DItakes several breaths to return to baseline. In contrast, at baseline,asthmatic subjects cannot maximally dilate their airways, and thisworsens considerably postconstriction. Moreover, after a DI, thedilation that does occur in airway caliber in asthmatic subjectsconstricts back to baseline much faster (often after a single breath).After albuterol, asthmatic subjects could dilate airways much closer tolevels of those of healthy subjects. These data suggest that theasthmatic smooth muscle resides in a stiffer biological state comparedwith the stimulated healthy smooth muscle, and inhibiting a DI inhealthy subjects cannot mimic this.

     

Effect of a previous voluntary deep breath on laryngeal resistance in normal and asthmatic subjects

We studied changes in both laryngeal resistance (Rla) and respiratory resistance (Rrs) after a voluntary deep breath in 7 normal and 20 asthmatic subjects. Rla was measured using a low-frequency sound method (Sekizawa et al. J. Appl. Physiol. 55: 591-597, 1983) and Rrs by forced oscillation at 3 Hz. In normal subjects, both Rla and Rrs significantly decreased after a voluntary deep breath (0.05 less than P less than 0.01). During methacholine provocation in the normal subjects, a voluntary deep breath significantly decreased Rrs (0.05 less than P less than 0.01, but Rla was significantly increased (0.05 less than P less than 0.01). In 10 asthmatic subjects in remission, a voluntary deep breath significantly increased Rrs (0.05 less than P less than 0.01) but significantly decreased Rla (0.05 less than P less than 0.01). In another 10 asthmatic subjects during spontaneous mild attacks, a voluntary deep breath significantly increased both Rrs and Rla (0.05 less than P less than 0.01). The present study showed that without obvious bronchoconstriction, Rla decreased after a voluntary deep breath in both normal and asthmatic subjects but, with bronchoconstriction, Rla increased in both groups. Subtraction of the change in Rla from Rrs gives the change in Rrs below the larynx (Rlow). Rlow changed little or decreased in normal subjects and increased in asthmatic subjects, irrespective of base-line bronchomotor tone. These results suggest that airway response below the larynx after a voluntary deep breath differentiates patients with bronchial asthma from normal subjects.     

Site of airway obstruction in pulmonary disease: direct measurement of intrabronchial pressure.

To partition the central and peripheral airway resistance in awake humans, a catheter-tipped micromanometer sensing lateral pressure of the airway was wedged into the right lower lobe of a 3-mm-ID bronchus in 5 normal subjects, 7 patients with chronic bronchitis, 8 patients with emphysema, and 20 patients with bronchial asthma. We simultaneously measured mouth flow, transpulmonary pressure, and intra-airway lateral pressure during quiet tidal breathing. Total pulmonary resistance (RL) was calculated from transpulmonary pressure and mouth flow and central airway resistance (Rc) from intra-airway lateral pressure and mouth flow. Peripheral airway resistance (Rp) was obtained by the subtraction of Rc from RL. The technique permitted identification of the site of airway resistance changes. In normal subjects, RL was 3.2 +/- 0.2 (SE) cmH2O.l-1.s and the ratio of Rp to RL was 0.24 during inspiration. Patients with bronchial asthma without airflow obstruction showed values of Rc and Rp similar to those of normal subjects. Although Rc showed a tendency to increase, only Rp significantly increased in those patients with bronchial asthma with airflow obstruction and patients with chronic bronchitis and emphysema. The ratio of Rp to RL significantly increased in three groups of patients with airflow obstruction (P less than 0.01). These observations suggest that peripheral airways are the predominant site of airflow obstruction, irrespective of the different pathogenesis of chronic airflow obstruction.     

Heat shock protein-27 protects human bronchial epithelial cells against oxidative stress-mediated apoptosis: possible implication in asthma

Inflammation of the human bronchial epithelium, as observed in asthmatics, is characterized by the selective death of the columnar epithelial cells, which desquamate from the basal cells. Tissue repair initiates from basal cells that resist inflammation. Here, we have evaluated the extent of apoptosis as well as the Hsp27 level of expression in epithelial cells from bronchial biopsy samples taken from normal and asthmatic subjects. Hsp27 is a chaperone whose expression protects against oxidative stress. We report that in asthmatic subjects the basal epithelium cells express a high level of Hsp27 but no apoptotic morphology. In contrast, apoptotic columnar cells are devoid of Hsp27 expression. Moreover, we observed a decreased resistance to hydrogen peroxide-induced apoptosis in human bronchial epithelial 16-HBE cells when they were genetically modified to express reduced levels of Hsp27.     

Left and Right Lung Asynchrony as a Physiological Indicator for Unilateral Bronchial Obstruction in Interventional Bronchoscopy

Background

In patients with bronchial obstruction, pulmonary function tests may not change significantly after intervention. The airflow asynchrony in both lungs due to unilateral bronchial obstruction may be applicable as a physiological indicator. The airflow asynchrony is reflected by the difference in the left and right lung sound development at tidal breathing.

Objectives

To investigate the usefulness of left and right lung asynchrony due to unilateral bronchial obstruction as a physiological indicator for interventional bronchoscopy.

Methods

Fifty cases with central airway obstruction were classified into three groups: tracheal, bronchial and extensive obstruction. The gap index was defined as the absolute value of the average of gaps between the left and right lung sound intensity peaks for a 12-second duration.

Results

Before interventional bronchoscopy, the gap index was significantly higher in the bronchial (p<0.05) and extensive obstruction groups (p<0.05) than in the tracheal group. The gap index in cases with unilateral bronchial obstruction of at least 80% (0.18±0.04 seconds) was significantly higher than in cases with less than 80% obstruction (0.02±0.01 seconds, p<0.05). After intervention for bronchial obstruction, the dyspnea scale (p<0.001) and gap index significantly improved (p<0.05), although no significant improvements were found in spirometric assessments. The responder rates for dyspnea were 79.3% for gap indexes over 0.06 seconds and 55.6% for gap indexes of 0.06 seconds or under.

Conclusions

Assessment of left and right lung asynchrony in central airway obstruction with bronchial involvement may provide useful physiological information for interventional bronchoscopy.     

Tussiphonogram in probands with chronic obstructive bronchitis

Tussiphonographic examinations were conducted in 21 probands admitted to hospital with chronic bronchitis, diagnosed by spirometry. Voluntary cough registered in subjects with obstructive chronic bronchitis appeared in the recordings as a marked multifarious sound, an increased mono-sound or a connected double-sound. The average value of cough sound intensity was increased to 244%, and the duration of cough was delayed to 77% when compared to normal values. No correlation was found between the changes observed in spirometric values, and values indicated by the tussiphonogram.     

The influence of the bronchodilatation test on the duration of forced expiratory tracheal noises in young men

The diagnostic efficiency of estimating the duration of forced expiratory noises under the conditions of bronchial obstruction has been shown. The objective of this study was to analyze the response of the forced expiratory noise duration to the bronchodilatation test with the β₂-agonist in the age- and genderhomogenous group of healthy volunteers and bronchial asthma patients selected as a model of variable bronchial obstruction. Two hundred and sixty young men (16–25 years old) were examined. It was shown that the prevailing type of response in bronchial asthma patients with spirometry confirmed bronchial obstruction was shortened forced expiratory noises. Furthermore, the degree of the shortening considerably depended on the severity of the background bronchial obstruction. The absence of a statistically significant response of the forced expiratory noise duration dominated among healthy volunteers (nonsmokers as well as smokers) and bronchial asthma patients without a spirometry confirmed bronchial obstruction. However, the shortened response occurred much more frequently in bronchial asthma patients than in healthy volunteers. The high specificity (86%) of the response as shortened forced expiratory noises to the β₂-agonist may be useful for diagnostics.     

Spectral analysis of breathing pattern in man

The periodic oscillations of breathing pattern parameters were studied in 34 healthy subjects. In a three minutes' resting spirometric recording we determined the duration of inspiration, expiration and tidal volume in successive breaths and computed autocorrelation functions and power spectral density. Ten of the subjects were re-examined 2 years later. Pulmonary functions were examined in all of them. Rhythmic changes lasting several respiratory cycles were found in the breathing pattern. Rhythmic changes in the duration of inspiration, expiration and tidal volume differed from one another in the same individual. The spectrograms of the individual breathing pattern parameters in the same individual changed during a 2-year period. Despite individual differences, the power spectral density correlations in the same subject and between different subjects two years later, and the mean curves for power spectral densities, show that in all the subjects the power fell at values of 0 to 0.05 Hz and was then maintained at a roughly constant level. Differences in the spectrograms of the various parameters in the same subject can hardly be attributed to a feedback between peripheral receptors and respiratory centres. Rhythmic changes are probably of central origin.     

Individual behavioral and autonomic response to emotional stress in humans

Healthy subjects (n = 53) performed a sound version of the proof-reading test under normal conditions and in the state of emotional stress. Stress resistance was evaluated by the overall number of errors. The propensity to active or passive response to stress was evaluated by the number of "false alarms" and signal omissions. The reaction pattern to emotional stress in stress-resistant subjects, irrespective of their behavioral features, consisted in an increase in sympathetic effects on the cardiac rhythm and a decrease in the reaction time to significant signals. In subjects with low stress resistance, no statistically significant changes in the level of sympathetic tone and reaction time were revealed in the state of stress. Subjects with active behavioral response to stress, irrespective of their level of stress resistance, were characterized by aggressiveness, boldness and independence. Subjects with passive response to stress were inclined to conformism, dependence, and passivity.     

Acoustic biomechanical relationships of human forced exhalation in bronchial obstruction

A statistically significant bidirectional influence of the incidence and degree of bronchial obstruction on the acoustic parameters of forced expiration and the spirometry/body plethysmography indicators of lung function has been revealed by means of nonparametric analysis of variance in a sample of 218 subjects. It has been shown that the acoustic band pass times and energies of forced expiratory tracheal noises coordinate with both tidal resistance and residual volume.     

Inflammatory and mechanical factors of allergen-induced bronchoconstriction in mild asthma and rhinitis.

We studied whether different bronchial responses to allergen in asthma and rhinitis are associated with different bronchial inflammation and remodeling or airway mechanics. Nine subjects with mild asthma and eight with rhinitis alone underwent methacholine and allergen inhalation challenges. The latter was preceded and followed by bronchoalveolar lavage and bronchial biopsy. The response to methacholine was positive in all asthmatic but in only two rhinitic subjects. The response to allergen was positive in all asthmatic and most, i.e., five, rhinitic subjects. No significant differences between groups were found in airway inflammatory cells or basement membrane thickness either at baseline or after allergen. The ability of deep inhalation to dilate methacholine-constricted airways was greater in rhinitis than in asthma, but it was progressively reduced in rhinitis during allergen challenge. We conclude that 1) rhinitic subjects may develop similar airway inflammation and remodeling as the asthmatic subjects do and 2) the difference in bronchial response to allergen between asthma and rhinitis is associated with different airway mechanics.     

Control of larynx during loaded breathing in normal subjects

We examined laryngeal resistance (Rla) in six normal subjects in control and four kinds of loaded breathing: hypercapnia, chest strapping, added external resistance, and inhaled methacholine. Rla was measured with a low-frequency sound methed (Sekizawa et al., J. Appl. Physiol. 55: 591-597, 1983). In control and the four kinds of loaded breathing, changes in Rla were tightly coupled with ventilation and Rla decreased during inspiration and increased during expiration. Hypercapnia and chest strapping significantly decreased Rla in both inspiration and expiration in all subjects. Added external resistance decreased inspiratory Rla in all subjects, but decreased expiratory Rla in three subjects, did not change it in two subjects, and increased it in one subject. Inhaled methacholine increased Rla in both inspiration and expiration in all subjects. The present study suggests that although laryngeal movement is tightly coupled with ventilation, laryngeal aperture may be determined by the complex competition of dilating and constricting mechanisms associated with the activity of the respiratory center and neural reflexes from the airway.     

Urban noise pollution

Noise is responsible for cochlear and general damages. Hearing loss and tinnitus greatly depend on sound intensity and duration. Short-duration sound of sufficient intensity (gunshot or explosion) will not be described because they are not currently encountered in our normal urban environment. Sound levels of less than 75 d (A) are unlikely to cause permanent hearing loss, while sound levels of about 85 d (A) with exposures of 8 h per day will produce permanent hearing loss after many years. Popular and largely amplified music is today one of the most dangerous causes of noise induced hearing loss. The intensity of noises (airport, highway) responsible for stress and general consequences (cardiovascular) is generally lower. Individual noise sensibility depends on several factors. Strategies to prevent damage from sound exposure should include the use of individual hearing protection devices, education programs beginning with school-age children, consumer guidance, increased product noise labelling, and hearing conservation programs for occupational settings.     

The effect of auditory image moving in vertical plane upon posture responses of humans

The influence of sound image motion on postural reactions was studied. The movement of sound source was created by successive switching of the loudspeakers situated over the arc in sagittal plane. Movement duration of sound stimulus was 1.6 s, 3.2 s and 4.8 s. The mean sway magnitudes decreased when the stimuli duration was 1.6 s and 3.2 s. Averaging of the wave-forms of center-of-pressure sway for signal with 4.8 s duration revealed that the sound image presentation induces body displacement in the direction opposite to that of sound image.