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At least 19 recordsLinked to original sources
PubMed2006

Diaphragm ultrasonography as an alternative to whole-body plethysmography in pulmonary function testing.

OBJECTIVE: Whole-body plethysmography is a common method of measuring pulmonary function. Although this technique provides a sensitive measure of pulmonary function, it can be problematic and unsuitable in some patients. The development of more accessible techniques would be beneficial. METHODS: A prospective study was performed to validate diaphragm ultrasonography as an alternative to whole-body plethysmography in patients referred for pulmonary function testing. Diaphragm movement and position were assessed by ultrasonography after standard pulmonary function testing using whole-body plethysmography. RESULTS: A wide range of lung function was observed. Standard lung volumes were as follows: total lung capacity, 5.57 +/- 1.31 L, residual volume, 2.27 +/- 0.56 L; and vital capacity, 3.30 +/- 0.98 L (mean +/- SD). The ratio of forced expiratory volume in 1 second to forced vital capacity was calculated as 0.69 +/- 0.08. Ultrasonography showed that mean diaphragm excursion values were 11.1 +/- 3.8 mm (2-dimensional), 14.7 +/- 4.1 mm during quiet breathing (M-mode), and 14.8 +/- 3.9 mm during a maximal sniff (M-mode). The velocity of diaphragm movement rose sharply during the sniff maneuver from 15.2 +/- 5.8 mm/s during quiet breathing to 104.0 +/- 33.4 mm/s. Static 2-dimensional measures of diaphragm position at the end of quiet inspiration or expiration correlated with standard measures of lung volume on plethysmography (eg, a correlation coefficient of 0.83 was obtained with end inspiration and vital capacity). All measures of diaphragm movement (whether by 2-dimensional or M-mode techniques) were poorly correlated with any lung volumes measured. CONCLUSIONS: These data suggest that dynamic measurements using diaphragm ultrasonography provide a relatively poor measure of pulmonary function in relation to whole-body plethysmography.

Adrenergic beta-Agonists↗
PubMed1998

Use of whole-body plethysmography to compare bronchodilator inhaler efficacy.

Whole-body plethysmography is not included in guidelines from regulatory authorities for the development of treatments or delivery devices for lung disease, despite its potential advantages compared to spirometry. Two separate studies were undertaken to assess the use of specific airway conductance (sGaw) as a pharmacodynamic endpoint for the comparison of two bronchodilator delivery systems (a novel dry powder inhaler and a standard metered dose inhaler). The first pilot study involved delivery of a single dose of salbutamol (200 micrograms) to 12 healthy volunteers and determination of sGaw up to 120 min after treatment. The second study involved delivery of cumulative doses of salbutamol (100, 200 and 400 micrograms) to 19 healthy volunteers with demonstrated reversibility of sGaw to the bronchodilator and measurement of sGaw up to 240 min after treatment. In both studies, increases in sGaw after treatment were significant compared to placebo and larger than the recorded increases in FEV1. Increases in sGaw were similar for both delivery devices and support the therapeutic equivalence of the two products. Power calculations indicated that the second study had appropriate statistical power to discriminate between treatments. It is concluded that the assessment of sGaw in healthy volunteers may be a useful and sensitive pharmacodynamic endpoint for use in the development of bronchodilators and their delivery devices.

Adult↗
PubMed1997

Determination of ventilatory volume in mice by whole body plethysmography.

We examined the reliability of whole-body plethysmography (WBP) for determining the ventilatory volume in mice. The degree of agreement of tidal volume (VT) determined consecutively by WBP with that by direct plethysmography (DP) or pneumotachography (PT) was analyzed using urethane-anesthetized young male 129/Sv mice. Between WBP and DP, the mean difference of VT was 0.000 ml with a 95% confidence interval of -0.003 to 0.002, whereas that between WBP and PT was 0.000 ml (-0.004 to 0.003). The limits of agreement, or mean +/- 2SD of the difference, were -0.008 and 0.008 ml in WBP vs. DP, and -0.011 and 0.010 ml in WBP vs. PT. These values were 5.1-6.6% of the average VT (0.157 ml in WBP and DP, and 0.165 ml in WBP and PT). Thus, VT can be determined by WBP without any bias and with a systemic error of less than 7% of that measured by the other direct methods examined. Through applying WBP to conscious 129/Sv and 129/SvJ-ICR hybrid mice, we further studied the effects of differences in mouse strain, age and sex on respiratory rate (f) and minute volume (V = VT.f), and their reflex changes in responses to systemic hypoxia and hypercapnia. V was significantly greater in young (10-16 weeks old) male 129/Sv than in young male 129/SvJ-ICR hybrids (139 +/- 11 and 73 +/- 8 ml/min/100 g, respectively), while the pattern of reflex responses was similar. In aged (32-44 weeks old) male 129/Sv, the basal level of V and its reflex increases were all diminished as compared to those in their young counter parts. However, we were unable to find significant differences between aged male and female 129/Sv mice. In conclusion, WBP is a useful and reliable method to determine ventilatory parameters in conscious and anesthetized mice. Furthermore, there are considerable strain- and age-related differences in baseline ventilation and reflex responses to hypoxia and hypercapnia.

Age Factors↗
PubMed1993

Whole-body plethysmography in the clinical assessment of infants with bronchopulmonary diseases.

Infant whole-body plethysmography offers a unique possibility of measuring end-expiratory resting level (thoracic gas volume; TGV), and hence lung volume in its close interrelationship to airway function (airway resistance; R(aw), its reciprocal value, airway conductance, Gaw). Therefore, this technique is a valuable aid for objective evaluation of lung diseases in infants. This article gives an overview of the physiological background of this particular measuring technique and its usefulness in the clinical routine. Plethysmographic data obtained in infant survivors of the infant respiratory distress syndrome (iRDS), in infants with cystic fibrosis (CF) and in the so-called 'wheezy infants' are presented. Special emphasis is given to the fact that in such infants the interrelationship between changes in end-expiratory resting level and the deficit in airway mechanics is of great importance and, consequently, for the determination of functional lung derangement in each particular case of lung disease, both TGV and the closely related R(aw) and Gaw have to be evaluated. This recommendation has to be kept in mind when the different diagnostic tools for evaluation of treatment facilities are applied in this particular young age group of patients with lung disease. In children as in adult patients, inhalative treatment must be considered the mainstay of all therapeutic measures. However, in infants, the efficacy of such treatment regimens must first be evaluated by adequate functional investigations. Infant whole-body plethysmography offers one such possibility.

Bronchitis↗
PubMed1999

Airway reactivity measured by barometric whole-body plethysmography in healthy cats.

OBJECTIVE: To assess the validity of barometric whole-body plethysmography (BWBP) as a means of monitoring airway responses to induced bronchoconstriction in healthy cats. ANIMALS: 8 healthy cats without history of bronchopulmonary disease or exposure to indoor tobacco smoke. PROCEDURE: Cats were placed into a barometric plethysmograph with an internal volume of 38 L, and air flow was recorded at baseline and after carbachol (concentrations 0.005, 0.01, 0.02, 0.05, 0.1, and 0.2%) was introduced into the chamber. A dose-response curve was generated for several flow-derived measurements, and airway reactivity was determined by interpolation of the dose-response curve for enhanced pause. RESULTS: Peak inspiratory and expiratory flows increased significantly, but respiratory rate, inspiratory and expiratory times, relaxation time, and tidal volume did not differ significantly from baseline values. Flow-derived measurements (pause, enhanced pause, and end-expiratory pause) increased significantly at carbachol concentrations > 0.02%. Baseline measurements did not correlate with indices of airway reactivity. CONCLUSIONS AND CLINICAL RELEVANCE: Airway reactivity can be measured by use of BWBP, which is noninvasive. Airway reactivity was highly variable among cats and was not a function of baseline airway caliber, suggesting that other intrinsic mechanisms may be important.

Animals↗
PubMed1985

The study of mechanical properties of rats lungs by whole body plethysmography.

A simple technic for studying the pulmonary mechanics of rats by whole body plethysmography is presented. The parameters measured were: Tidal Volume (TV); Respiratory Frequency (RF); Transpulmonary Basal Pressure (TBP); Dynamic Compliance (Cdyn); Functional Residual Capacity (FRC); Transpulmonary Pressure/Volume curve (TP/V); Forced Expiratory Volume of 1/4 second (FEV 1/4); Expiratory Reserve Volume (ERV); Inspiratory Capacity (IC); Inspiratory Reserve Volume (IRV); Forced Vital Capacity (FVC); Residual Volume (RV); Forced Expiratory Mean Flow between 100-50% (FEMF 100-50), 50-25% (FEMF 50-25) and 25-0% (FEMF 25-0) of the FVC, and Total Lung Capacity (TLC). In order to verify the accuracy of the technic, common male adult Wistar rats, in which pulmonary obstructive disease is normally expected, were first submitted to these functional tests and then to pathological examination. According to the intensity of the morphological pulmonary lesion, the rats were divided in two groups: with and without suppurative pneumopathy. The analysis of the pulmonary function data showed significant decrease of the FEV 1/4 and FEMF 50-25 and increase of the FRC and RV in the groups with pulmonary suppuration. Thus, a discriminant function could be established to characterize the two groups with 100% efficiency. It was concluded that these pulmonary function tests are a valuable and reliable tool to detect lung diseases in rats.

Animals↗
PubMed2005

Emotions and airway resistance in asthma: study with whole body plethysmography.

The role of emotions as potential triggers of asthmatic airway obstructions was examined by whole body plethysmography. Three affectively homogeneous picture series (IAPS) were presented with video glasses to induce pleasant, unpleasant, and neutral emotional states in 32 asthmatic and 32 nonasthmatic participants while they were seated in a Jaeger Bodytest plethysmograph. Airway resistance, specific airway resistance, thoracic gas volume, and mood were measured immediately after each presentation, in addition to specific airway resistance before and during each presentation. Airway resistance and specific airway resistance were significantly increased after and during pleasant and unpleasant stimulation compared to neutral stimulation in asthmatic patients and also, but less pronounced, in nonasthmatic controls. The results show that the experience of pleasant and unpleasant emotions can provoke increased airway resistance especially in asthmatic patients.

Adult↗
PubMed2002

Carbon dioxide accumulation during small animal, whole body plethysmography: effects on ventilation, indices of airway function, and aerosol deposition.

Barometric (whole body) plethysmography is used to examine changes in ventilation and breathing pattern in unrestrained animals during exposure to therapeutic or toxic aerosols. Whole body plethysmographs (WBP) may be operated with a bias flow in order to maintain an adequate supply of oxygen and remove expired CO(2). However, some aerosol generation and delivery methods may require operation of the WBP without bias flow, which would artificially deplete aerosol concentration. Under these conditions, expired CO(2) accumulates in the plethysmograph and stimulates ventilation, increasing total aerosol deposition, shifting regional deposition, and significantly altering some airway function indices. We characterized these effects in guinea pigs using a commercially available 4.5-L WBP, with and without a 1 L/min bias flow. CO(2)-induced changes in breathing frequency (f), tidal volume (Vt), minute ventilation (Ve), and indices of airway function -- including enhanced pause (penh), flow derived parameter (FDP), and respiratory duty cycle -- were measured. Without bias flow, CO(2) in the plethysmograph increased steadily to 5.4% after 30 min compared to a steady state 0.9% with bias flow. This resulted in a moderate suppression of f, and significant increases in Vt and Ve by factors of 1.5 and 1.4, respectively. Changes in regional deposition were stimulated for 300 mg/m(3) polydisperse aerosols with mass median aerodynamic diameters of 0.3, 1, 3, or 7 microm and geometric standard deviations of 1.7. Percent increase in aerosol deposition from CO(2) inhalation ranged from 24% to 90%, by mass, depending on aerosol size distribution and respiratory tract region. In addition, fractional deposition shifted toward the pulmonary region. Empirical indices of airway constriction, penh and FDP, also were increased significantly to 1.7 and 1.3 times their respective baseline values. The study quantifies the effect of inadvertent coexposure to CO(2) on ventilation, aerosol deposition, and airway function in WBP evaluation of aerosol effects in airway function.

Administration, Inhalation↗