Inflation of antishock trousers increases bronchial response to methacholine in healthy subjects

1990 ◽  
Vol 68 (4) ◽  
pp. 1528-1533 ◽  
Author(s):  
J. Regnard ◽  
P. Baudrillard ◽  
B. Salah ◽  
A. T. Dinh Xuan ◽  
L. Cabanes ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Vital Capacity ◽  
Alternative Explanation ◽  
Venous Occlusion ◽  
Forced Expiratory Volume ◽  
Lower Limbs ◽  
Base Line ◽  
Lung Volumes ◽  
Residual Capacity ◽  
Lung Vessels

We studied changes in lung volumes and in bronchial response to methacholine chloride (MC) challenge when antishock trousers (AST) were inflated at venous occlusion pressure in healthy subjects in the standing posture, a maneuver known to shift blood toward lung vessels. On inflation of bladders isolated to lower limbs, lung volumes did not change but bronchial response to MC increased, as evidenced by a greater fall in the forced expiratory volume in 1 s (FEV1) at the highest dose of MC used compared with control without AST inflation (delta FEV1 = 0.94 +/- 0.40 vs. 0.66 +/- 0.46 liter, P less than 0.001). Full inflation of AST, i.e., lower limb and abdominal bladder inflated, significantly reduced vital capacity (P less than 0.001), functional residual capacity (P less than 0.01), and FEV1 (P less than 0.01) and enhanced the bronchial response to MC challenge compared with partial AST inflation (delta FEV1 = 1.28 +/- 0.47 liter, P less than 0.05). Because there was no significant reduction of lung volumes on partial AST inflation, the enhanced bronchial response to MC cannot be explained solely by changes in base-line lung volumes. An alternative explanation might be a congestion and/or edema of the airway wall on AST inflation. Therefore, to investigate further the mechanism of the increased bronchial response to MC, we pretreated the subjects with the inhaled alpha 1-adrenergic agonist methoxamine, which has both direct bronchoconstrictor and bronchial vasoconstrictor effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Deep breaths, methacholine, and airway narrowing in healthy and mild asthmatic subjects

2002 ◽  
Vol 93 (4) ◽  
pp. 1384-1390 ◽  
Author(s):  
Emanuele Crimi ◽  
Riccardo Pellegrino ◽  
Manlio Milanese ◽  
Vito Brusasco
Keyword(s):  
Forced Vital Capacity ◽  
Healthy Subjects ◽  
Vital Capacity ◽  
Forced Expiratory Volume ◽  
Forced Expiration ◽  
Airway Narrowing ◽  
Significant Difference ◽  
Mild Asthmatic ◽  
Residual Capacity ◽  
Airway Conductance

Deep breaths taken before inhalation of methacholine attenuate the decrease in forced expiratory volume in 1 s and forced vital capacity in healthy but not in asthmatic subjects. We investigated whether this difference also exists by using measurements not preceded by full inflation, i.e., airway conductance, functional residual capacity, as well as flow and residual volume from partial forced expiration. We found that five deep breaths preceding a single dose of methacholine 1) transiently attenuated the decrements in forced expiratory volume in 1 s and forced vital capacity in healthy ( n = 8) but not in mild asthmatic ( n = 10) subjects and 2) increased the areas under the curve of changes in parameters not preceded by a full inflation over 40 min, during which further deep breaths were prohibited, without significant difference between healthy ( n = 6) and mild asthmatic ( n = 16) subjects. In conclusion, a series of deep breaths preceding methacholine inhalation significantly enhances bronchoconstrictor response similarly in mild asthmatic and healthy subjects but facilitates bronchodilatation on further full inflation in the latter.

scholarly journals Effects of rapid saline infusion on lung mechanics and airway responsiveness in humans

2003 ◽  
Vol 95 (2) ◽  
pp. 728-734 ◽  
Author(s):  
Riccardo Pellegrino ◽  
Raffaele Dellacà ◽  
Peter T. Macklem ◽  
Andrea Aliverti ◽  
Stefania Bertini ◽  
...  
Keyword(s):  
Functional Residual Capacity ◽  
Forced Vital Capacity ◽  
Vital Capacity ◽  
Forced Expiratory Volume ◽  
Airway Responsiveness ◽  
Saline Infusion ◽  
Lung Mechanics ◽  
Elastic Recoil ◽  
Lung Volumes ◽  
Residual Capacity

Lung mechanics and airway responsiveness to methacholine (MCh) were studied in seven volunteers before and after a 20-min intravenous infusion of saline. Data were compared with those of a time point-matched control study. The following parameters were measured: 1-s forced expiratory volume, forced vital capacity, flows at 40% of control forced vital capacity on maximal (V̇m40) and partial (V̇p40) forced expiratory maneuvers, lung volumes, lung elastic recoil, lung resistance (Rl), dynamic elastance (Edyn), and within-breath resistance of respiratory system (Rrs). Rl and Edyn were measured during tidal breathing before and for 2 min after a deep inhalation and also at different lung volumes above and below functional residual capacity. Rrs was measured at functional residual capacity and at total lung capacity. Before MCh, saline infusion caused significant decrements of forced expiratory volume in 1 s, V̇m40, and V̇p40, but insignificantly affected lung volumes, elastic recoil, Rl, Edyn, and Rrs at any lung volume. Furthermore, saline infusion was associated with an increased response to MCh, which was not associated with significant changes in the ratio of V̇m40 to V̇p40. In conclusion, mild airflow obstruction and enhanced airway responsiveness were observed after saline, but this was not apparently due to altered elastic properties of the lung or inability of the airways to dilate with deep inhalation. It is speculated that it was likely the result of airway wall edema encroaching on the bronchial lumen.

Dependence of maximal flow-volume curves on time course of preceding inspiration

1993 ◽  
Vol 75 (3) ◽  
pp. 1155-1159 ◽  
Author(s):  
E. D'Angelo ◽  
E. Prandi ◽  
J. Milic-Emili
Keyword(s):  
Time Course ◽  
Vital Capacity ◽  
Normal Subjects ◽  
Forced Expiratory Volume ◽  
Flow Volume ◽  
Maximal Flow ◽  
Lung Volumes ◽  
Residual Capacity ◽  
Expiratory Flow ◽  
Volume Range

Thirteen normal subjects, sitting in a body plethysmograph and breathing through a pneumotachograph, performed forced vital capacity maneuvers after a rapid inspiration without or with an end-inspiratory pause (maneuvers 1 and 2) and after a slow inspiration without or with an end-inspiratory pause (maneuvers 3 and 4), the pause lasting 4–6 s. Inspirations were initiated close to functional residual capacity. At all lung volumes, expiratory flow was larger with maneuver 1 than with any other maneuver and, over the upper volume range, larger with maneuver 3 than with maneuver 4, whereas it was similar for maneuvers 2 and 4. Relative to corresponding values with maneuver 4, peak expiratory flow was approximately 16 and approximately 4% larger with maneuvers 1 and 3, respectively, whereas forced expiratory volume in 1 s increased by approximately 5% only with maneuver 1. The time dependence of maximal flow-volume curves is consistent with the presence of viscoelastic elements within the respiratory system (D'Angelo et al. J. Appl. Physiol. 70: 2602–2610, 1991).

Nonlinear increases in diffusing capacity during exercise by seated and supine subjects

1981 ◽  
Vol 51 (4) ◽  
pp. 858-863 ◽  
Author(s):  
D. L. Stokes ◽  
N. R. MacIntyre ◽  
J. A. Nadel
Keyword(s):  
Carbon Monoxide ◽  
Oxygen Consumption ◽  
Healthy Subjects ◽  
Vital Capacity ◽  
Maximal Exercise ◽  
Sitting Position ◽  
Diffusing Capacity ◽  
Heavy Exercise ◽  
Lung Volumes ◽  
Rate Of Increase

To study the effects of exercise on pulmonary diffusing capacity, we measured the lungs' diffusing capacity for carbon monoxide (DLCO) during exhalation from 30 to 45% exhaled vital capacity in eight healthy subjects at rest and during exercise while both sitting and supine. We found that DLCO at these lung volumes in resting subjects was 26.3 +/- 3.2% (mean +/- SE) higher in the supine than in the sitting position (P less than 0.001). We also found that, in both positions, DLCO at these lung volumes increased significantly (P less than 0.001) with increasing exercise and approached similar values at maximal exercise. The pattern of increase in DLCO with an increase in oxygen consumption in both positions was curvilinear in that the rate of increase in DLCO during mild exercise was greater than the rate of increase in DLCO during heavy exercise (P = 0.02). Furthermore, in the supine position during exercise, it appeared that DLCO reached a physiological maximum.

STUDIES OF RESPIRATORY PHYSIOLOGY IN CHILDREN

PEDIATRICS ◽  
1959 ◽  
Vol 24 (2) ◽  
pp. 181-193
Author(s):  
C. D. Cook ◽  
P. J. Helliesen ◽  
L. Kulczycki ◽  
H. Barrie ◽  
L. Friedlander ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Respiratory Rate ◽  
Vital Capacity ◽  
Total Lung Capacity ◽  
Lung Compliance ◽  
Respiratory Physiology ◽  
Residual Volume ◽  
Lung Volumes ◽  
Lung Capacity ◽  
Residual Capacity

Tidal volume, respiratory rate and lung volumes have been measured in 64 patients with cystic fibrosis of the pancreas while lung compliance and resistance were measured in 42 of these. Serial studies of lung volumes were done in 43. Tidal volume was reduced and the respiratory rate increased only in the most severely ill patients. Excluding the three patients with lobectomies, residual volume and functional residual capacity were found to be significantly increased in 46 and 21%, respectively. These changes correlated well with the roentgenographic evaluation of emphysema. Vital capacity was significantly reduced in 34% while total lung capacity was, on the average, relatively unchanged. Seventy per cent of the 61 patients had a signficantly elevated RV/TLC ratio. Lung compliance was significantly reduced in only the most severely ill patients but resistance was significantly increased in 35% of the patients studied. The serial studies of lung volumes showed no consistent trends among the groups of patients in the period between studies. However, 10% of the surviving patients showed evidence of significant improvement while 15% deteriorated. [See Fig. 8. in Source Pdf.] Although there were individual discrepancies, there was a definite correlation between the clinical evaluation and tests of respiratory function, especially the changes in residual volume, the vital capacity, RV/ TLC ratio and the lung compliance and resistance.

Bronchial responsiveness to inhaled methacholine in young asymptomatic smokers

1982 ◽  
Vol 52 (6) ◽  
pp. 1464-1470 ◽  
Author(s):  
J. L. Malo ◽  
S. Filiatrault ◽  
R. R. Martin
Keyword(s):  
Respiratory Symptoms ◽  
Vital Capacity ◽  
Forced Expiratory Volume ◽  
Threshold Concentration ◽  
Base Line ◽  
Similar Reaction ◽  
Response Curves ◽  
Bronchial Responsiveness ◽  
Young Smokers ◽  
Males And Females

Methacholine inhalation challenges were performed in 10 young smokers who denied having respiratory symptoms and in 10 nonsmokers of the same age. There were five males and five females in each group. The bronchoconstriction was evaluated with specific lung conductance (sGL), maximum partial (initiated from end-inspiratory lung volume) expiratory flows assessed at 40% vital capacity breathing air (Vmax40p air), and a He-O2 mixture (Vmax40p He), and with maximum complete flows breathing He-O2 [forced expiratory volume at 1 s (FEV1), Vmax50c He]. Dose-response curves were studied for 1) threshold concentration (TC) where values depart by more than two SD from base line; 2) provocative concentration (PC) causing a fixed fall in a parameter. Smokers differed significantly from nonsmokers for TC and PC accessed by Vmax40p He (P less than 0.001 and P less than 0.01, respectively), Vmax40p air (P less than 0.01), and Vmax50c He (P less than 0.01 and P less than 0.05, respectively). TC and PC estimated by sGL and FEV1 were not significantly different. Males and females showed a similar reaction.

A comparison of lung volumes between divers and submariners in the Royal Navy

1984 ◽  
Vol 70 (3) ◽  
pp. 143-148
Author(s):  
G. M. Clifford ◽  
D. J. Smith ◽  
Cardine S. M. Searing
Keyword(s):  
Linear Regression ◽  
Forced Vital Capacity ◽  
Vital Capacity ◽  
Forced Expiratory Volume ◽  
Royal Navy ◽  
Predictive Equations ◽  
Lung Volumes ◽  
Job Classification ◽  
Single Breath ◽  
Expected Values

SummaryA comparison of spirometric values in divers and submariners of the Royal Navy and their physical characteristics was undertaken. Four hundred and twenty-two subjects were included in the study, of whom 192 were divers and 230 submariners. Measurements of forced vital capacity (FYC), forced expiratory volume in one second (FEY1) and FEY1/FYC ratio were made using a single breath wedge spirometer (YitalographR). The data was analysed by multiple linear regression and analysis of variance. FYC and FEY1 increased with height and decreased with age though inclusion of a quadratic age term showed that the decline with age did not begin until the mid-thirties, casting doubt on the validity of predictive equations which assume a linear decrease from age 25. The divers had significantly larger lung volumes than the submariners though in the former this did not correlate with either experience or job classification. The FEY1/FYC ratio declined with age in both groups. It was also shown that those individuals with a large FYC tend to have a relatively lower FEY1/FYC ratio than those with small FYCs. Predictive equations for both divers and submariners were calculated which are more appropriate for determining expected values for the two groups than hose currently in use.

Effect of lung volume on forced expiratory flows during rapid thoracoabdominal compression in infants

1995 ◽  
Vol 78 (5) ◽  
pp. 1993-1997 ◽  
Author(s):  
J. Hammer ◽  
C. J. Newth
Keyword(s):  
Lung Volume ◽  
Vital Capacity ◽  
Forced Expiration ◽  
Flow Volume ◽  
Older Children ◽  
Lung Volumes ◽  
Volume Segment ◽  
Forced Expiratory Flow ◽  
Residual Capacity ◽  
End Tidal

The rapid thoracoabdominal compression (RTC) technique is commonly used in pulmonary function laboratories to assess flow-volume relationships in infants unable to produce a voluntary forced expiration maneuver. This technique produces forced expiratory flows over only a small lung volume segment (i.e., tidal volume). It has been argued that the RTC technique should be modified to measure flow-volume relationships over a larger portion of the vital capacity range to imitate the voluntary maximal forced expiratory maneuver obtained in older children and adults. We examined the effect of volume history on forced expiratory flows by generating forced expiratory flow-volume curves by RTC from well-defined inspiratory volumes delineated by inspiratory pressures of 10, 20, 30, and 40 cmH2O down to residual volume (i.e., the reference volume) in seven intubated and anesthetized infants with normal lungs [age 8.0 +/- 2.0 (SE) mo, weight 6.7 +/- 0.6 kg]. We compared maximal expiratory flows at isovolume points (25 and 10% of forced vital capacity) and found no significant differences in maximal isovolume flow rates measured from the different lung volumes. We conclude that there is no obvious need to initiate RTC from higher lung volumes if the technique is used for flow comparisons. However, compared with measurements of maximal flows at functional residual capacity by RTC from end-tidal inspiration, the initiation of RTC from a defined and reproducible inspiratory level appears to decrease the intrasubject variability of the maximal expiratory flows at low lung volumes.

Volumes and Breathing Patterns during Speech in Healthy and Asthmatic Subjects

1988 ◽  
Vol 31 (2) ◽  
pp. 219-227 ◽  
Author(s):  
Robert G. Loudon ◽  
Linda Lee ◽  
Barbara J. Holcomb
Keyword(s):  
Gas Exchange ◽  
Lung Volume ◽  
Healthy Subjects ◽  
Vital Capacity ◽  
Breathing Patterns ◽  
Volume Changes ◽  
Lung Volumes ◽  
Flow Rates ◽  
Communication Needs ◽  
Limited Period

The lung volumes and ventilatory patterns used by 10 healthy subjects and 14 patients with varying degrees of asthma were studied. The protocol included conversation, monologue, and counting at two loudness levels. Lung-volume changes were measured with a Respitrace and recorded with associated speech sounds. Volumes, durations, and flows were analyzed for sequences of respiratory cycles. Asthmatics used a greater percentage of their reduced vital capacity. Their inspiratory flow rates were slower, and expiratory rates faster. Asthmatics spent a greater proportion of the total respiratory cycle time on inspiration, and expired a greater volume of gas without sound. Patterns of ventilation suggested that asthmatics favored respiratory over communication needs to a greater extent than healthy subjects. Activities that forced priority to communication needs (counting to a metronome) were inadequate for gas exchange in asthmatics and could be sustained for only a limited period of time.

The Interpretation of Different Measurements of Airways Obstruction in the Presence of Lung Volume Changes in Bronchial Asthma

1978 ◽  
Vol 54 (3) ◽  
pp. 313-321
Author(s):  
K. B. Saunders ◽  
M. Rudolf
Keyword(s):  
Lung Volume ◽  
Time Course ◽  
Forced Expiratory Volume ◽  
Specific Conductance ◽  
Volume Changes ◽  
Lung Volumes ◽  
Bronchodilator Response ◽  
Before And After ◽  
Residual Capacity ◽  
Airways Resistance

1. We measured changes in peak expiratory flow rate (PEFR), forced expiratory volume in 1 s (FEV1·0), airways resistance (Raw), specific conductance (sGaw), residual volume (RV), functional residual capacity (FRC) and total lung capacity (TLC) in 44 patients with asthma. 2. When asthma was induced by exercise in five patients there were large changes in volumes, but these did not obscure changes in PEFR, which adequately defined the time course of the response. 3. In 70 comparisons before and after inhalation of bronchodilator drug in 33 asthmatic subjects, the responses were classified by the size of the change in lung volumes, which showed a concordant improvement, or no change, in 61 comparisons. Despite these lung volume changes, measurement of both PEFR and FEV1·0, would have detected a bronchodilator response in all but two cases. 4. In 81 comparisons in 23 subjects over time intervals varying from 1 day to 11 months, lung volumes changed in concordance with PEFR and FEV1·0 in 59. In eight of these comparisons, measurement of lung volumes would have altered our interpretation of the changes in PEFR and FEV1·0. 5. In the same 81 comparisons changes in airways resistance were concordant with changes in PEFR and FEV1·0 on 44 occasions, with minor discordant changes in 19. We could not explain the remaining 18 cases showing major discordance between these two types of measurement of airway calibre. 6. We conclude that both FEV1·0, and PEFR should be used for detection of a bronchodilator response, and that measurement of lung volumes will rarely contribute to the interpretation. Over longer periods, lung volumes should be measured if possible. We found no practical use for routine measurement of airways resistance in patients with asthma.

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