Biomedical subjects

D Pavia

Publications and source records attributed to D Pavia.

At least 19 recordsLinked to original sources

PubMed1994

No effect of gender on lung mucociliary clearance in young healthy adults.

Lung mucociliary clearance (LMC) depends on age and it is adversely affected by cigarette smoking. When using the radioaerosol technique for measuring LMC the initial site of deposition of the radioaerosol within the lungs affects its rate of removal. Whether there is a difference in gender for LMC is still an open question. Forty-one (20 female, 21 male) healthy, non-smoking subjects had their lung mucociliary clearance measured using an objective, non-invasive radioaerosol technique. The male and female groups were closely matched for initial distribution of the radioaerosol. There was no statistical significant difference between males and females in the rate of clearance of inhaled radioaerosol over a 6 h observation period. When comparing the LMC of two groups although it is important to match them for age, smoking habits and initial topographical distribution of the tracer radioaerosol it does not seem essential to also match the two groups for gender.

Adult↗

PubMed1994

Regional lung clearance during cough and forced expiration technique (FET): effects of flow and viscoelasticity.

BACKGROUND: In vitro studies have suggested that both the viscoelastic properties of lung secretions and the peak flow attained during simulated cough influence clearance. This study examines the possible association of the viscoelastic properties of sputum and maximum expiratory flow with measured effectiveness of mucus clearance induced by instructed cough and by forced expiration technique (FET) in patients with airways obstruction. METHODS: Nineteen patients (11 men and eight women) of mean (SE) age, % predicted FEV1, and daily sputum wet weight of 64 (2) years, 52 (6)%, and 37.5 (7.9) g respectively participated in the study. Mucus movement from proximal and peripheral lung regions was measured by an objective non-invasive radioaerosol technique. Each patient underwent three assessments: control, cough, and FET. During cough and FET, maximum expiratory flow was measured at the mouth level. Apparent viscosity and elasticity of the expectorated sputum samples were measured with a viscometer. RESULTS: Compared with the control run (mean (SE) clearance: 16 (3)%) there was an increase in clearance from the whole lung during cough (44 (5)%) and FET (42 (5)%), and also an enhanced clearance of inhaled, deposited radioaerosol from the trachea, inner and intermediate regions of the lungs, but not from the outer region. There were, however, no differences in regional clearance between cough and FET. Neither regional nor total clearance correlated with maximum expiratory flow, apparent viscosity, elasticity, or daily sputum wet weight. CONCLUSIONS: These results confirm that cough and FET both promote effective clearance but suggest that, unlike in vitro studies, sputum production and viscoelasticity, as well as maximum expiratory flow, provide no guide to clearance efficacy in humans.

Bronchiectasis↗

PubMed1994

Inhaled frusemide does not affect lung mucociliary clearance in healthy and asthmatic subjects.

Inhaled frusemide has been shown to protect against the bronchoconstrictor effect of several inhaled agents in asthmatic subjects by mechanism(s) that are unclear. Since loop diuretics can modulate Cl- transport in the airway epithelium, frusemide may alter the quality and/or the quantity of the periciliary layer, which in turn may affect lung mucociliary transport. We investigated the effect of a single inhalation of nebulized frusemide (40 mg) on lung mucociliary clearance in four healthy subjects and in seven stable, mild asthmatics using an objective radioaerosol technique. Frusemide or placebo was inhaled in a double-blind, randomized, cross-over manner half an hour after the inhalation of 5 microns polystyrene particles labelled with 99mTc, used for assessing mucociliary clearance. The pulmonary function and initial radioaerosol distribution were similar between frusemide and placebo runs within each of the two study groups. The areas under the tracheobronchial retention curves over the 6 h observation period were similar between frusemide and placebo runs for both groups. Our findings show inhaled frusemide, at a dose known to inhibit bronchoconstrictor responses, does not affect lung mucociliary clearance.

Administration, Inhalation↗

PubMed1994

Regional mucus transport following unproductive cough and forced expiration technique in patients with airways obstruction.

It has previously been shown that unproductive coughing in both healthy subjects and patients with airways obstruction is not effective in clearing lung secretions. This study investigates the regional mucus transport in a group of subjects with airways obstruction who failed to expectorate following instructed cough and forced expiration technique. Fourteen patients (mean +/- SEM age: 68 +/- 2 years) with airways obstruction (mean +/- SEM percent predicted. FEV1: 54 +/- 5; daily wet weight sputum: 9.1 +/- 2.0 g) took part in the study which was a randomized, three-way crossover within-patient design. Each patient underwent three treatment maneuvers: control, cough (30 coughs over a 10-min period), and forced expiration (30 forced expirations over a 10-min period). An objective radioaerosol technique was used to monitor regional mucus movement within the lungs of the patients. The lungs were divided arbitrarily into four regions of interest: tracheal, inner, intermediate, and outer. Peak expiratory flow rate during cough and forced expiration was measured at the mouth. There was no correlation between the radioaerosol clearance from all regions and (1) mean peak flow during cough and forced expiration, and (2) mean 24-h sputum production prior to the study day. There were no differences in regional radioaerosol clearance between cough and forced expiration. However, both cough and forced expiration resulted in significant clearance compared with control for all regions with the exception of the forced expiration in the outer region. To our knowledge, this study is the first to demonstrate that unproductive cough and forced expiration result in movement of secretions proximally from all regions of the lung in patients with airways obstruction.

Cough↗

PubMed1993

Effect of oral bronchodilators on lung mucociliary clearance during sleep in patients with asthma.

BACKGROUND: Lung mucociliary clearance rates are reduced during sleep in patients with asthma. Methylxanthines and beta 2 agonists have been shown to enhance rates of lung mucociliary clearance. This study examined whether oral slow release bronchodilators may also have an effect on this clearance mechanism during sleep in patients with asthma. METHODS: Nine patients with asthma with a mean(SE) age of 65(5) years and percentage predicted forced expiratory volume in one second (FEV1 of 61(9)% participated in a double blind, placebo controlled, within subject crossover study to assess the effect of two weeks of treatment with salbutamol (Volmax; 8 mg twice daily) or theophylline (Phyllocontin; 350 mg twice daily) on lung mucociliary clearance during sleep. Lung mucociliary clearance rates were measured by a radioaerosol technique. RESULTS: The observation period for radioaerosol clearance was approximately 0.3 hours before sleep, 6.0 hours during sleep and 0.6 hours after sleep. Mean mucociliary clearance rates for theophylline, placebo and salbutamol before sleep were: 39, 39, and 32%/hour respectively; during sleep: 11, 10, and 9%/hour respectively; and after sleep: 39, 32, and 35%/hour respectively. CONCLUSION: During sleep lung mucociliary clearance in stable asthma was reduced, which is in agreement with the group's previous findings. Treatment with controlled/slow release oral bronchodilators had no effect on this reduced rate of clearance associated with sleep.

Aged↗

PubMed1992

Acute effect of inhaled bradykinin on tracheobronchial clearance in normal humans.

BACKGROUND: Bradykinin, a nonapeptide that contributes as a mediator to the pathogenesis of asthma, may affect lung mucociliary clearance, as it has been shown to be a potent secretagogue in canine airways and in human nasal mucosa in vivo. To evaluate this possibility the effect of inhaled bradykinin on mucociliary clearance has been studied in 10 healthy volunteers. METHODS: Subjects attended the laboratory on two occasions to take part in tracheobronchial clearance studies using a non-invasive radioisotopic technique. Inhalation of radioaerosol was followed 30 minutes later by inhalation of either bradykinin (8 mg/ml) or vehicle placebo in a randomised, double blind fashion. After each inhalation the number of coughs was recorded. Whole lung radioactivity was measured every half hour for six hours with two collimated scintillation counters, and a tracheobronchial clearance curve was plotted for each subject on each occasion. RESULTS: Mucociliary clearance, expressed as the area under the tracheobronchial radioaerosol retention curve calculated for the first six hours (AUC0-6h), was greater in nine out of 10 subjects after inhalation of bradykinin than after placebo. The median values (range) for AUC0-6h were significantly reduced from 126% (78-232%)/h with placebo to 87% (51-133%)/h with bradykinin. CONCLUSION: It is concluded that acute exposure to inhaled bradykinin accelerates tracheobronchial clearance in normal human airways.

Administration, Inhalation↗

PubMed1992

Effect of temazepam on tracheobronchial mucus clearance.

BACKGROUND: Tracheobronchial clearance of mucus from the lungs is reduced during sleep and, usually, by the administration of opiates. It seemed possible therefore that temazepam, a widely used potent benzodiazepine, retarded clearance. METHODS: The effect of 10 mg temazepam on mucociliary clearance was studied in eight healthy volunteers, aged 18-50 (mean 30) years, in a randomised, placebo controlled, double blind, cross-over study. Six subjects were female and two male. Six were non-smokers and two were light current smokers. Clearance was assessed from the change in radio-activity in the lungs after inhalation of 5 microns diameter polystyrene particles, labelled with technetium-99m, under controlled conditions. RESULTS: Tracheobronchial clearance was reduced by 22% after temazepam by comparison with placebo during the first three hours after drug ingestion; this is the period when circulating drug concentrations are highest. CONCLUSION: Temazepam should be prescribed with caution in patients with impaired lung mucociliary transport.

Adolescent↗

PubMed1992

Tracheobronchial clearance in patients with pulmonary sarcoidosis.

Lung mucociliary clearance was measured using an objective, noninvasive radioaerosol technique in 13 patients with pulmonary sarcoidosis and 13 matched, healthy control subjects. Four of the sarcoid patients had never received any steroid therapy, five were currently receiving oral corticosteroids, and the remaining four were using inhaled corticosteroids only. A statistically significant retardation in tracheobronchial clearance (p less than 0.02) was observed in the sarcoid patients compared to the control subjects. The sarcoid patients using inhaled corticosteroids appeared to demonstrate the greatest degree of mucociliary transport impairment. The sarcoid patients in apparent remission and those receiving oral corticosteroid therapy had clearances better than those using inhaled corticosteroids, but they were still reduced compared to the control subjects. This study demonstrates that lung mucociliary clearance is adversely affected in patients with pulmonary sarcoidosis and raises the question of the possible consequences that could follow long-term inhaled immunosuppressive therapy on the prime clearance defense mechanism within the human lungs.

Adrenal Cortex Hormones↗

PubMed1992

Impairment of lung mucociliary clearance in pigeon fanciers.

Lung mucociliary clearance was measured in 15 pigeon fanciers. The study group was subdivided into two: a precipitin-positive group (n = 10; mean +/- SEM age 45 +/- 5 years) with circulating blood precipitins and a precipitin-negative group (n = 5; mean +/- SEM age 40 +/- 3 years) without. Clearance was measured using an objective, noninvasive radioaerosol technique. The data for both groups were compared with those of matched control groups of healthy subjects. The mean +/- SEM area under the tracheobronchial retention curves (AUC) over the 6-h observation period was 257 +/- 27 %h for the precipitin-positive group compared with 177 +/- 16 %h for its control group (p = 0.02)--a high AUC value denoting slow clearance. That for the precipitin-negative group was 282 +/- 34 %h compared with 150 +/- 15 %h for its control group (p = 0.02). Our study illustrates in pigeon fanciers involvement of the conducting airways in that a major defense mechanism of the airways--namely, mucociliary clearance--is substantially compromised. The presence or absence of precipitins appears not to be related to the degree of mucociliary clearance impairment.

Bird Fancier's Lung↗

PubMed1991

The effect of unproductive coughing/FET on regional mucus movement in the human lungs.

The study was designed to ascertain the movement of mucus from proximal and peripheral regions within the human lungs during cough and the forced expiration technique (FET). Mucus movement was measured using a radioaerosol technique. Seven patients (mean +/- SEM age: 63 +/- 3 years) with airways obstruction (% predicted FEV1: 44 +/- 4) participated in the study. Each patient underwent three assessments in a randomized manner: control/cough/FET. Peak expiratory flow rate (PEFR) was measured at the mouth during cough and FET. None of the patients produced sputum during the assessment periods. Both cough and FET compared with control increased, on average, mucus clearance from all regions; statistical significance was achieved only for central lung regions with cough (P less than 0.05). There was no significant correlation between PEFR during cough/FET and regional lung clearance.

Aerosols↗

PubMed1991

Effect of inhaled 15-(s)-hydroxyeicosatetraenoic acid on tracheobronchial clearance in normal human airways.

15-(s)-Hydroxyeicosatetraenoic acid (15-HETE) is the predominant metabolite of arachidonic acid in normal and asthmatic human airways and a potent mucus secretagogue in canine and human airways. A study was carried out on the effect of inhaled 15-HETE on tracheobronchial clearance, measured for six hours by a radioaerosol technique, in 10 normal subjects. Subjects inhaled 80 nmol 15-HETE or the diluent (sodium phosphate buffer) on two occasions at least two weeks apart in a double blind and randomised fashion (20 minutes after radioaerosol inhalation. Tracheobronchial clearance after inhaled 15-HETE was almost identical to that after placebo for all measurements up to six hours. It is concluded that 15-HETE has no effect on tracheobronchial clearance in normal human airways and is unlikely to account for the impaired mucociliary clearance seen in asthma.

Administration, Inhalation↗

PubMed1991

Bronchoalveolar clearance.

The lungs possess several mechanisms for cleansing themselves from locally produced biological debris and inhaled, deposited soluble and insoluble materials. Insoluble particles deposited on the conducting, ciliated airways will be primarily removed by mucociliary clearance, over a period of several hours, with cough acting as a back-up clearance mechanism. Insoluble particles deposited in the non-ciliated, alveolated regions of the lungs will be cleared primarily by the macrophages very slowly, with a biological half-life of several months. Soluble substances can pass through paracellular pathways and be cleared via the blood stream.

Absorption↗

PubMed1990

The role of chest physiotherapy in mucus hypersecretion.

Review of the data shows that chest physiotherapy (CP) is effective in clearing secretions from the lungs of patients with copious secretions (i.e., daily sputum production in excess of 30 ml). Assessment of the various components of CP shows that percussion, vibratory shaking, and breathing exercises have little to offer. Although instructed cough, the back up mucus clearance mechanism, is effective in clearing secretions its effect is less than that achieved with the forced expiration technique (FET). Postural drainage (PD) is on the whole successful in helping to drain secretions in the lungs. The administration of a beta 2-agonist via a nebulizer prior to CP in addition to promoting bronchodilation may also help to alter the physical properties of secretions, rendering them more amenable for clearance by FET/cough. Technology regarding high-frequency oscillations (HFO) has yet to be improved and its efficacy in clearing excess secretions proven prior to its inclusion in a CP treatment regimen. Intermittent positive pressure breathing (IPPB) may have a role to play in those patients where conventional CP is not possible. Data with positive expiratory pressure (PEP) are encouraging and direct evaluation is awaited regarding its effect on mucus clearance. With our present knowledge it seems reasonable to recommend that physiotherapists concentrate their CP treatment on the following: administration of a nebulized beta 2-agonist followed by PD and FET.

Breathing Exercises↗

PubMed1990

Tracheobronchial clearance in patients with bilateral diaphragmatic weakness.

Tracheobronchial clearance was measured in seven patients with bilateral diaphragmatic weakness using a noninvasive objective radioaerosol technique. The data were compared with those from seven healthy nonsmoking control subjects matched for physical characteristics and studied under the same experimental conditions; the control subjects were drawn from a data bank of healthy subjects and were matched to the patients for age, sex, and the initial distribution of their radioaerosol deposition. Pulmonary function indices (FEV1, FVC, PEFR, and MMFR25-75) for the patients were all significantly (p less than 0.01) reduced compared with those for the control subjects. The initial topographic distribution of the radioaerosol within the lungs of the patients and control groups was similar: alveolar deposition [mean (SD)] was 36.4 (6.7) versus 41.0 (4.0)%, and penetration index was 0.56 (0.08) versus 0.56 (0.03), respectively. Tracheobronchial clearance of deposited radioaerosol over a 6-h observation period after inhalation showed a marked reduction (p less than 0.02) in the patients: area under the clearance curve (between zero and 6 h) was 262 (80)% h for the patients and 142 (41)% h for the healthy control subjects. These data suggest that in patients with bilateral diaphragmatic weakness, mucociliary clearance is depressed, or that reduced mechanical movement of the lungs can itself impair clearance of secretions from the lungs. Impaired clearance from either cause may contribute to an increased incidence of chest infections in severe respiratory muscle weakness.

Adult↗

PubMed1989

Effect of four-week treatment with oxitropium bromide on lung mucociliary clearance in patients with chronic bronchitis or asthma.

The effect of oxitropium bromide on lung mucociliary clearance, pulmonary function and viscoelastic properties of sputum was investigated in 10 asthmatics and 10 chronic bronchitics. A controlled, double-blind, crossover study was performed. Following a baseline (B) measurement the patients were, in a random order, allocated placebo (P) or oxitropium bromide (O; 0.1 mg/puff), administered from metered dose inhalers, which they used for 4 weeks at a dose of 2 puffs t.d.s. This test medication was used in conjunction with their normal medication. At the end of the treatment period the patients were assessed, the treatments were then crossed over and a final assessment made 4 weeks later. The administration of oxitropium bromide resulted in (1) small but statistically significant increases in pulmonary function (less than 10% vs. placebo); (2) increased penetrance of radioaerosol into the lungs (mean +/- SEM alveolar deposition: 35 +/- 3, 26 +/- 3 and 24 +/- 3% for the O, P and B runs respectively; p less than 0.025); (3) no significant change in particle clearance rate from the lungs despite their deeper penetration (mean +/- SEM area under the tracheobronchial clearance curves between 0 and 6 h: 317 +/- 26, 324 +/- 25 and 287 +/- 25%.h for the O, P and B runs respectively; p greater than 0.1); (4) no alteration in sputum production, and (5) no significant changes in apparent viscosity (mean +/- SEM: 640 +/- 162, 446 +/- 79 and 557 +/- 115 mPa.s for the O, P and B runs, respectively; p greater than 0.1) and elasticity (mean +/- SEM: 3,682 +/- 1,383, 1,779 +/- 353 and 2,061 +/- 366 mPa for the O, P and B runs, respectively; p greater than 0.1) of sputum. When the two groups, i.e. the chronic bronchitics and asthmatics, were studied separately, no significant differences in any parameter measured (other than radioaerosol penetrance which was significantly enhanced on oxitropium bromide in chronic bronchitics) were noted between the three assessments.

Aged↗

PubMed1988

Subcutaneous adrenaline versus terbutaline in the treatment of acute severe asthma.

Subcutaneous adrenaline and terbutaline have been compared in a double blind study of 20 patients with acute severe asthma presenting to an accident and emergency department. Ten patients received adrenaline 0.5 mg (0.5 ml) and 10 terbutaline 0.5 mg (0.5 ml) subcutaneously. Further treatment with nebulised salbutamol (5 mg), hydrocortisone (200 mg), and aminophylline (0.9 mg/kg/hour) was started 15 minutes later. All patients reported a reduction in chest tightness within three minutes of receiving both adrenaline and terbutaline and reported no adverse effects. Mean baseline values of peak expiratory flow (PEF) and forced expiratory volume in one second (FEV1) did not differ significantly between the adrenaline group (130 1 min-1 and 0.83 l) and the terbutaline group (111 1 min-1 and 0.63 l). After administration of adrenaline PEF had increased by 21% and FEV1 by 40% five minutes after the injection, and by 35% and 64% at 15 minutes. Terbutaline caused a 23% increase in PEF and a 37% increase in FEV1 at five minutes, and a 40% and 58% increase at 15 minutes. There was no significant difference in PEF, FEV1, heart rate, blood pressure, or pulsus paradoxus between the two groups at any time. Continuous electrocardiographic recording showed no abnormalities in either group. Thus in this study subcutaneous adrenaline (0.5 mg) and terbutaline (0.5 mg) produced effective rapid bronchodilatation without serious side effects.

Acute Disease↗

PubMed1988

Efficacy of "mucoregulatory" agents in Young's syndrome.

Eight patients with Young's syndrome were treated with four "mucoregulatory" agents for eight weeks in a randomised, open crossover study. There was no improvement in tracheobronchial clearance, pulmonary function, or sperm count.

Adult↗

PubMed1988

Impaired mucus clearance in patients with chronic bronchial sepsis, sinusitis and dextrocardia.

Published reports have indicated that patients with Kartagener's syndrome (dextrocardia, sinusitis and bronchiectasis) have no significant lung mucociliary clearance. With a radioaerosol technique we measured over a 6-hour observation period the tracheobronchial clearance of 8 patients with dextrocardia, chronic bronchial sepsis and chronic sinusitis (DC). The tracheobronchial clearance of these patients was significantly reduced (p less than 0.02) compared with that of 29 healthy subjects of similar age. However, even when allowance was made for productive coughing during the observation period, the reduced clearance was much better than anticipated from published reports in patients with Kartagener's syndrome, which confined their observations to a 2-hour period. The tracheobronchial clearance of the DC patients, adjusted for productive coughing, was as bad as that found in an older group of patients with chronic obstructive airways disease who refrained from expectorating during the equivalent test period. Our study implies one or more of the following possibilities: (a) a spectrum of mucociliary impairment in patients with DC; (b) an effective cough clearance deeper in the lung than hitherto believed, and (c) two-phase flow of mucus cephalad as an effective clearance mechanism in patients with DC.

Bronchi↗