Changes In Pulmonary Mechanics Research Articles

Active bronchial anaphylaxis in the rat: inhibition by tiaramide.

Intravenous administration of the benzothiazoline derivative tiaramide hydrochloride, to rats actively sensitized to ovalbumin, inhibited immunologic lung reactions in a dose-related manner. Methysergide also inhibited anaphylactic lung reactions. Serotonin, but not other chemical mediators, produced changes in pulmonary mechanics qualitatively similar to those produced by the sensitizing antigen. The bronchoconstrictive action of serotonin was blocked by methysergide and tiaramide. The latter drug also inhibited bronchoconstriction induced by methacholine. The results implicate serotonin as the primary mediator of the respiratory component of systemic anaphylaxis in the rat: however, the mechanism by which tiaramide inhibits anaphylactic bronchoconstriction remains to be elucidated.

Effects of intravenous histamine on lung mechanics in man after beta-blockade.

In six nonatopic normal subjects, neither intravenous histamine infusion (0.3 mg.kg-1.min-1) nor intravenous propanolol (10 mg) alone produced significant change in pulmonary mechanics. Histamine infusion after propranolol resulted in an increase in pulmonary resistance (RL) from 2.1 +/- 0.41 (mean +/- 1 SE) to 3.3 +/- 0.76 cmH2O./-1.S-1 (P greater than 0.05); maximal flow at 50% total lung capacity (Vmax 50) decreased from 3.6 +/- 0.35 to 2.7 +/- 0.44 l/s (P greater than 0.01). Similar changes in Vmax 50 were observed during partial forced expiratory maneuvers from end-tidal inspiration (PEFV). On 80:20 helium-oxygen mixture Vmax 50 during maximal expiration (MEFV) decreased from 4.9 +/- 0.61 to 3.4 +/- 0.61 l/s (P greater than 0.005) and during PEFV diminished from 4.6 +/- 0.61 to 2.8 +/- 0.46 l/s (P greater than 0.005). Density dependence (deltaVmax 50) decreased significantly (P greater than 0.05) during PEFV but not during MEFV. There were no significant changes in tidal pulmonary compliance, in closing volume and closing capacity (resident gas technique), and in inflation and deflation pressure-volume curves. We conclude that iv histamine in low doses constricts peripheral conducting airways in man but this effect is masked by histamine-induced release of catecholamines from the adrenal glands.

Investigation of the role of histamine in antigen-induced bronchoconstriction in the ascaris-hypersensitive dog.

1 Aerosol administration of ascaris antigen to the airways of ascaris-hypersensitive dogs provoked increases in pulmonary resistance (Rp) and decreases in dynamic lung compliance (Cdyn). These changes in pulmonary mechanics were not inhibited by the histamine H1-receptor antagonists, diphenhydramine or mepyramine. 2 Increases in Rp and decreases in Cdyn induced by a histamine aerosol were markedly or totally inhibited by comparable doses of these H1-antihistamines. 3 Doses of antigen which produced pathophysiological pulmonary responses failed to produce a detectable histamine release from the cardiopulmonary system in vivo. Aerosol antigen provocation, equivalent to 5 to 9 times greater than that which produced substantial pathophysiological pulmonary responses, did cause histamine release in vivo. 4 The canine cardiopulmonary system showed only a modest ability to remove and/or degrade circulating histamine. 5 It is concluded that histamine may not play a major role in mediating the acute antigen-induced bronchoconstriction in the ascaris-hypersensitive dog.

Time and Volume Dependence of Changes in Pulmonary Mechanics during Chest Strapping

Time and Volume Dependence of Changes in Pulmonary Mechanics during Chest Strapping

Comparison of measures of forced expiration

Theoretical relationships among a number of parameters were derived for idealized timed vital capacity (TVC) and maximal expiratory flow-volume (MEFV) curves to determine a minimal set of independent parameters. Normal pediatric subjects and those with cystic fibrosis were studied to verify these relationships experimentally. The average flow over the middle half (FEF25-75%) of the forced vital capacity (FVC) and flows at various exhaled percentages of the FVC (FEF50%, FEF75%), as well as moments of the TVC and MEFV curves were computed. From the TVC moments, a mean transit time (MTT) and an index of dispersion (ID) were also calculated. The minimum information needed to detect pulmonary mechanical changes associated with obstructive lung disease requires at least two reproducible measures: one related to the mean slope (e.g., FEF25-75%/FVC or MTT) and the other to the shape (e.g;, ID) of the effort-independent portion of the MEFV curve.

Instrumentation for measuring respiratory impedance by forced oscillations.

Recent reports have suggested that the frequency dependence of the respiratory impedance may provide a sensitive method for characterizing early changes in pulmonary mechanics. A modification of the forced-oscillation technique provides an experimental method for obtaining the necessary data. A loudspeaker was used to provide the pressure oscillations, and the magnitudes and phase angle of the transduced pressure and flow signals were measured with a special electronics unit. A test comparing predicted values of a standard impedance (a 5-g bottle) to experimental data indicates that the measured amplitude is within 10 percent and the measured phase within over the frequency range of 1-16 Hz. Dog studies showed that measurements at all frequencies up to 16 Hz were reproducible within a few percent of the mean value on a given animal. Data obtained following bronchoconstriction and its reversal in six dogs indicate that the measurements are sensitive to alterations in pulmonary mechanics. Data from two dog models of clinical disease suggest that the technique may provide meaningful diagnostic information.

Sex and age differences in pulmonary mechanics in normal nonsmoking subjects

Maximun flow-volume, static pressure-volume, and maximum flow static recoil curves of three groups of nonsmoking, normal subjects (young men, young women, elderly women) were used to assess age and sex differences in pulmonary mechanics. No significant sex differences in maximum flow were seen but the young men showed higher lung recoil pressures at full inflation. When the influence of the inspiratory muscles and chest wall was excluded by exponential extrapolation of the pressure-volume curves to a maximum volume the bulk elastic properties of the lungs of young men and women appeared identical. Loss of maximum expiratory flow at low lung volumes and of lung recoil pressure occurred with age in nonsmoking women in whom emphysema should be minimal and therefore indicate true physiological effects of aging. The changes in pulmonary mechanics with age are consistent with an increase in unstressed dimensions and loss of elastic recoil of both alveoli and airways.

A method for measuring respiratory mechanics in small newborn (premature) infants.

ArticleA method for measuring respiratory mechanics in small newborn (premature) infants.G Polgar, and G LacourtG Polgar, and G LacourtPublished Online:01 Apr 1972https://doi.org/10.1152/jappl.1972.32.4.555MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmailWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByPulmonary Function and Graphics ∗ ∗This chapter uses a number of figures and tables from the same chapter in the previous edition of the book, written by Drs. Bhutani and Benitz. The section on resistive properties is unaltered from the previous edition’s chapter.A contemporary evaluation of pulmonary function in children undergoing lung resection in infancyJournal of Pediatric Surgery, Vol. 46, No. 5Pulmonary Function and GraphicsPhysiology4 April 2013Postnatal Changes in Pulmonary Mechanics and Energetics of Infants with Respiratory Distress Syndrome following Surfactant Treatment17 June 2005 | Neonatology, Vol. 87, No. 4Evaluation of Pulmonary Function in the NeonatePULMONARY FUNCTION AND GRAPHICSClinical applications of pulmonary function and graphicsSeminars in Neonatology, Vol. 7, No. 5Pulmonary sequelae of insults to the lung in early lifePediatric Pulmonology, Vol. 19, No. 2Pulmonary mechanics and energetics of normal, non-ventilated low birthweight infantsPediatric Pulmonology, Vol. 8, No. 2Pneumotachographic Measurements of Lung Function in Preterm Infants with Respiratory Distress SyndromeSequential pulmonary function measurements in very low-birth weight infants during the first week of lifePediatric Pulmonology, Vol. 3, No. 6Pulmonary and Chest Wall Mechanics in the Control of Respiration in the NewbornClinics in Perinatology, Vol. 14, No. 3Compliance measurement in respiratory distress syndrome: The prediction of outcomePediatric Pulmonology, Vol. 2, No. 6Computerized estimates of functional residual capacity in infantsAnnals of Biomedical Engineering, Vol. 9, No. 3THEORETICAL CONSIDERATIONS AND METHODSActa Paediatrica, Vol. 63, No. s247DEVELOPMENT OF PULMONARY FUNCTION IN LATE GESTATION: I. The Functional Residual Capacity of the Lung in Premature ChildrenActa Paediatrica, Vol. 63, No. 1 More from this issue > Volume 32Issue 4April 1972Pages 555-9 https://doi.org/10.1152/jappl.1972.32.4.555PubMed5026510History Published online 1 April 1972 Published in print 1 April 1972 Metrics

Reversibility of airway obstruction in chronic obstructive lung disease.

The effect of intravenous aminophylline on pulmonary mechanics was investigated in 31 patients with chronic obstructive lung disease. Significant decrease in pulmonary resistance and early increase in dynamic compliance were characteristic of patients with asthma and bronchitis whereas in patients with emphysema change in resistance was insignificant and increase in dynamic compliance was delayed. Patients with bronchial asthma showed greater decrease in inspiratory resistance than patients with chronic bronchitis and greater decrease in both inspiratory and expiratory resistance than patients with chronic bronchitis and emphysema. Study of changes in pulmonary mechanics after a bronchodilator might be useful in distinguishing various types of chronic obstructive lung disease.

Nasal surgery. Physiological considerations of nasal obstruction.

CONTINUED medical contributions have been made in the field of pulmonary physiology, especially in the last decade, with the development of medical electronics. However, little attention has been paid to nasal breathing by most pulmonary physiologists. By applying the methods which are widely employed for pulmonary function tests, to nasal as well as mouth respiration, we have shown that nasal obstruction has a definite influence on pulmonary functions.1-4 This paper deals with changes in pulmonary mechanics in patients with nasal obstruction, through the separation of pulmonary resistance into its components, airway and pulmonary tissue resistance. Preoperative and postoperative data is presented showing the return of various abnormalities in function to normal following successful nasal surgery upon the obstructed nose. Review of Literature A few pulmonary physiologists such as Speizer et al5and Ferris et al,6using their own techniques, measured the resistance of various parts of the

Respiratory mechanics following open-heart surgery for acquired valvular disease.

1. Pulmonary mechanics were determined preoperatively and postoperatively in 20 patients following open-heart surgery for acquired valvular disease. 2. The surviving patients had minimal increase of the work of breathing, associated with an increase in nonelastic resistance during the early postoperative period. These changes in pulmonary mechanics are insufficient to explain the respiratory difficulties experienced by these patients. 3. In the fatal cases compliance decreased to half the preoperative level, and respiratory work increased to five times the preoperative value. In these individuals excessive work of breathing produces a significant demand on physiological resources, and controlled mechanical ventilation is indicated.

Changes in pulmonary mechanics induced by melatonin

The effect of melatonin, a substance isolated from the pineal body, was examined on the pulmonary mechanics of intact dogs before and after vagotomy. The following results were obtained: 1. 1. A decrease in total lung resistance; 2. 2. An increase in lung compliance; 3. 3. Inhibition of 5-hydroxytryptamine induced bronchoconstriction; 4. 4. The bronchodilation and inhibition are most probably caused by local and indirect action of melatonin on the bronchial smooth muscle.