Airway distensibility in healthy and asthmatic subjects: effect of lung volume history

2000 ◽  
Vol 88 (4) ◽  
pp. 1413-1420 ◽  
Author(s):  
David Peter Johns ◽  
John Wilson ◽  
Richard Harding ◽  
E. Haydn Walters
Keyword(s):  
Lung Volume ◽  
Total Lung Capacity ◽  
Normal Subjects ◽  
Residual Volume ◽  
Tidal Breathing ◽  
Lung Capacity ◽  
Mild Asthmatic ◽  
The Relationship ◽  
Asthmatic Group ◽  
Volume History

Anatomic dead space (Vd) is known to increase with end-inspiratory lung volume (EILV), and the gradient of the relationship has been proposed as an index of airway distensibility (ΔVd). The aims of this study were to apply a rapid method for measuring ΔVd and to determine whether it was affected by lung volume history. Vd of 16 healthy and 16 mildly asthmatic subjects was measured at a number of known EILVs by using a tidal breathing, CO2-washout method. The effect of lung volume history was assessed by using three tidal breathing regimens: 1) three discrete EILVs (low/medium/high; LMH); 2) progressively decreasing EILVs from total lung capacity (TLC; TLC-RV); and 3) progressively increasing EILVs from residual volume (RV; RV-TLC). ΔVd was lower in the asthmatic group for the LMH (25.3 ± 2.24 vs. 21.2 ± 1.66 ml/l, means ± SE) and TLC-RV (24.3 ± 1.69 vs. 18.7 ± 1.16 ml/l) regimens. There was a trend for a lower ΔVd in the asthmatic group for the RV-TLC regimen (23.3 ± 2.19 vs. 18.8 ± 1.68 ml/l). There was no difference in ΔVd between groups. In conclusion, mild asthmatic subjects have stiffer airways than normal subjects, and this is not obviously affected by lung volume history.

Effect of volume history on changes in DLcoSB-3EQ with lung volume in normal subjects

1992 ◽  
Vol 73 (2) ◽  
pp. 434-439 ◽  
Author(s):  
D. J. Cotton ◽  
F. Taher ◽  
J. T. Mink ◽  
B. L. Graham
Keyword(s):  
Lung Volume ◽  
Normal Subjects ◽  
Breath Holding ◽  
Diffusing Capacity ◽  
Tidal Breathing ◽  
Inspiratory Capacity ◽  
Deep Breath ◽  
Residual Capacity ◽  
The Relationship ◽  
Volume History

The purpose of this study was to determine the relationship between the three-equation diffusing capacity for carbon monoxide (DLcoSB-3EQ) and lung volume and to determine how this relationship was altered when maneuvers were immediately preceded by a deep breath. DLcoSB-3EQ maneuvers were performed in nine healthy subjects either immediately after a deep breath or after tidal breathing for 10 min. The maneuvers consisted of slow inhalation of test gas from functional residual capacity to 25, 50, 75, or 100% of the inspiratory capacity and, without breath holding, slow exhalation to residual volume. After either a deep breath or tidal breathing, we found that DLcoSB-3EQ decreased nonlinearly with decreasing lung volume. At all lung volumes, DLcoSB-3EQ was significantly greater when measured after a deep breath than after tidal breathing. This effect increased as lung volume decreased, so that the greatest difference between DLcoSB-3EQ after a deep breath and that after tidal breathing occurred at the lowest lung volume. We conclude that a deep breath or spontaneous sigh has a role in reestablishing the pathway for gas exchange during tidal breathing.

Pulmonary resistance and state of inflation of lungs in normal subjects and in patients with airway obstruction

1959 ◽  
Vol 14 (5) ◽  
pp. 727-732 ◽  
Author(s):  
Tsung O. Cheng ◽  
Malcolm P. Godfrey ◽  
Richard H. Shepard
Keyword(s):  
High Resistance ◽  
Lung Volume ◽  
Vital Capacity ◽  
Total Lung Capacity ◽  
Normal Subjects ◽  
Viscous Resistance ◽  
Pulmonary Resistance ◽  
Lung Capacity ◽  
Normal Resistance ◽  
The Relationship

The relationship between pulmonary resistance and the state of inflation of the lung was estimated throughout the expired vital capacity, using the multiple interrupter of Clements and Elam and a servo-spirometer. In normal subjects the pulmonary resistance was lowest near full inflation and remained relatively constant until about 80% of the vital capacity had been expired. It then rose abruptly and approached infinity at full expiration. In patients with obstructed airways, this relationship was altered in one of several ways: 1) normal resistance near full inflation increasing to high levels early in the expired vital capacity, 2) high resistance near full inflation with little further rise until late in expiration and 3) various combinations of the above. The first pattern probably reflects changes in the small, relatively flaccid airways while the second pattern probably reflects changes in the large, relatively rigid airways or in pulmonary viscous resistance. The type of relationship between resistance and lung volume also appears to influence the partition of the total lung capacity. Submitted on February 17, 1959

Relative compliances of well and poorly ventilated spaces in the normal human lung

1964 ◽  
Vol 19 (5) ◽  
pp. 937-945 ◽  
Author(s):  
K. T. Fowler
Keyword(s):  
Lung Volume ◽  
Total Lung Capacity ◽  
Normal Subjects ◽  
Lung Compliance ◽  
Qualitative Behavior ◽  
Residual Volume ◽  
Lung Capacity ◽  
Normal Human ◽  
Expired Gas ◽  
Series Of Experiments

A series of experiments was performed in each of which the subject inspired a .25-liter bolus of argon in a large breath consisting otherwise of air. The slope of the argon plateau in the subsequent expiration was found to depend upon the lung volume at which the bolus was administered. When inspiring from residual volume to total lung capacity, bolus injection at a low lung volume led to a rising plateau; injection at medium volume led to a flat plateau; and at a high lung volume to a steeply falling plateau. From measurements of the different plateau slopes produced it was possible to deduce the ratio of the effective compliances shown at any lung volume by the “well” and “poorly” ventilated alveolar populations. In four normal subjects this ratio rose from about 0.5 at residual volume to about 4 near total lung capacity. The qualitative behavior of the two populations resembled that of the upper and lower zones of the erect lung, as indicated by the nature of the cardiac oscillations on the expired gas plateaus. lung compliance, range of variation; lung compliance, variation with lung volume Submitted on January 20, 1964

Inspiratory muscles during exercise: a problem of supply and demand

1988 ◽  
Vol 64 (6) ◽  
pp. 2482-2489 ◽  
Author(s):  
P. Leblanc ◽  
E. Summers ◽  
M. D. Inman ◽  
N. L. Jones ◽  
E. J. Campbell ◽  
...  
Keyword(s):  
Lung Volume ◽  
Static Pressure ◽  
Total Lung Capacity ◽  
Supply And Demand ◽  
Normal Subjects ◽  
Esophageal Pressure ◽  
Maximum Exercise ◽  
Lung Capacity ◽  
Inspiratory Muscles ◽  
Residual Capacity

The capacity of inspiratory muscles to generate esophageal pressure at several lung volumes from functional residual capacity (FRC) to total lung capacity (TLC) and several flow rates from zero to maximal flow was measured in five normal subjects. Static capacity was 126 +/- 14.6 cmH2O at FRC, remained unchanged between 30 and 55% TLC, and decreased to 40 +/- 6.8 cmH2O at TLC. Dynamic capacity declined by a further 5.0 +/- 0.35% from the static pressure at any given lung volume for every liter per second increase in inspiratory flow. The subjects underwent progressive incremental exercise to maximum power and achieved 1,800 +/- 45 kpm/min and maximum O2 uptake of 3,518 +/- 222 ml/min. During exercise peak esophageal pressure increased from 9.4 +/- 1.81 to 38.2 +/- 5.70 cmH2O and end-inspiratory esophageal pressure increased from 7.8 +/- 0.52 to 22.5 +/- 2.03 cmH2O from rest to maximum exercise. Because the estimated capacity available to meet these demands is critically dependent on end-inspiratory lung volume, the changes in lung volume during exercise were measured in three of the subjects using He dilution. End-expiratory volume was 52.3 +/- 2.42% TLC at rest and 38.5 +/- 0.79% TLC at maximum exercise.

Fast vs. slow exhalation before O2 inhalation alters subsequent phase III slope

1984 ◽  
Vol 56 (1) ◽  
pp. 52-56 ◽  
Author(s):  
T. S. Hurst ◽  
B. L. Graham ◽  
D. J. Cotton
Keyword(s):  
Total Lung Capacity ◽  
Normal Subjects ◽  
Phase Iii ◽  
Breath Holding ◽  
Small Airways ◽  
Residual Volume ◽  
Lung Capacity ◽  
Single Breath ◽  
Subsequent Phase ◽  
Phase Iii Slope

We studied 10 symptom-free lifetime non-smokers and 17 smokers all with normal pulmonary function studies. All subjects performed single-breath N2 washout tests by either exhaling slowly (“slow maneuver”) from end inspiration (EI) to residual volume (RV) or exhaling maximally (“fast maneuver”) from EI to RV. After either maneuver, subjects then slowly inhaled 100% O2 to total lung capacity (TLC) and without breath holding, exhaled slowly back to RV. In the nonsmokers seated upright phase III slope of single-breath N2 test (delta N2/l) was lower (P less than 0.01) for the fast vs. the slow maneuver, but this difference disappeared when the subjects repeated the maneuvers in the supine position. In contrast, delta N2/l was higher for the fast vs. the slow maneuver (P less than 0.01) in smokers seated upright. For the slow maneuver, delta N2/l was similar between smokers and nonsmokers but for the fast maneuvers delta N2/l was higher in smokers than nonsmokers (P less than 0.01). We suggest that the fast exhalation to RV decreases delta N2/l in normal subjects by decreasing apex-to-base differences in regional ratio of RV to TLC (RV/TLC) but increases delta N2/l in smokers, because regional RV/TLC increases distal to sites of small airways obstruction when the expiratory flow rate is increased.

Respiratory movements of the vocal cords

1983 ◽  
Vol 54 (5) ◽  
pp. 1269-1276 ◽  
Author(s):  
T. Brancatisano ◽  
P. W. Collett ◽  
L. A. Engel
Keyword(s):  
Lung Volume ◽  
Respiratory Control ◽  
Respiratory Muscles ◽  
Normal Subjects ◽  
Tight Coupling ◽  
Tidal Breathing ◽  
Vocal Cords ◽  
Residual Capacity ◽  
The Relationship ◽  
Respiratory Movements

We examined the movements of the vocal cords during tidal breathing, panting, and large changes in lung volume in 12 normal subjects. The glottis was observed with a fiber-optic bronchoscope, and the glottic image was recorded together with flow, volume, and a time marker onto videotape. Phasic respiratory swings in glottic width (dg) and glottic area (Ag) were reproducible in all subjects but differed substantially between subjects. In the group as a whole dg and Ag increased during inspiration to 10.1 +/- 5.6 mm and 126 +/- 8 mm2 (mean +/- SE), respectively, whereas during expiration the lowest values were 5.7 +/- 0.5 mm and 70 +/- 7 mm2, respectively. These extreme dimensions corresponded closely to the midtidal volume points in the respiratory cycle. Glottic width during vital capacity (VC) expirations was nearly 30% greater at a flow of 1.2 l/s than at 0.5 l/s, but the relationship between dg and lung volume differed between subjects. When swings in dg were minimized by panting, there was no difference in dg between functional residual capacity (FRC) and a volume corresponding to midinspiratory capacity. However, tidal breathing at this lung volume was associated with a 20% decrease in dg compared with breathing at FRC. Our observations indicate a tight coupling between the pattern of glottic movement and the respiratory volume cycle. The results suggest that during voluntary respiratory maneuvers both intrinsic laryngeal and respiratory muscles are recruited, participating as effector organs in ventilatory and respiratory control.

Effect of Lung Volume on Voice Onset Time (VOT)

1993 ◽  
Vol 36 (3) ◽  
pp. 516-520 ◽  
Author(s):  
Jeannette D. Hoit ◽  
Nancy Pearl Solomon ◽  
Thomas J. Hixon
Keyword(s):  
Lung Volume ◽  
Total Lung Capacity ◽  
Voice Onset Time ◽  
Onset Time ◽  
Speech Disorders ◽  
Residual Volume ◽  
Healthy Individuals ◽  
Lung Volumes ◽  
Lung Capacity

This investigation was designed to test the hypothesis that voice onset time (VOT) varies as a function of lung volume. Recordings were made of five men as they repeated a phrase containing stressed /pi/ syllables, beginning at total lung capacity and ending at residual volume. VOT was found to be longer at high lung volumes and shorter at low lung volumes in most cases. This finding points out the need to take lung volume into account when using VOT as an index of laryngeal behavior in both healthy individuals and those with speech disorders.

Effects of lung volume on collateral and airways resistance in man

1979 ◽  
Vol 46 (1) ◽  
pp. 67-73 ◽  
Author(s):  
C. R. Inners ◽  
P. B. Terry ◽  
R. J. Traystman ◽  
H. A. Menkes
Keyword(s):  
Functional Residual Capacity ◽  
Lung Volume ◽  
Total Lung Capacity ◽  
Lung Capacity ◽  
Residual Capacity ◽  
Collateral Pathways ◽  
Flow Through ◽  
Airways Resistance ◽  
Young Subjects ◽  
The Relationship

The effects of changing lung volume (VL) on collateral resistance (Rcoll) and total airways resistance (Raw) were compared in six young volunteers. At functional residual capacity (FRC) = 55% total lung capacity (TLC), mean Rcoll was 4,664 +/- 1,518 (SE) cmH2O/(l/s) and mean Raw was 1.57 +/- 0.11 (SE) cmH2O/l/s). When VL increased to 80% TLC, Rcoll decreased by 63.3 +/- 7.8%, and Raw decreased by 50.3 +/- 4.2 (SE) %. The decrease in Rcoll with increasing lung volume was not statistically different from that of Raw (P less than 0.05). If the airways obstructed for measurements of Rcoll served between 2 and 5% of the lungs, then Rcoll was approximately 50 times as great as the resistance to flow through airways serving the same volume of lung at FRC. The relationship did not change significantly when VL increased by 25% TLC. If changes in Raw reflect changes in airways supplying sublobar portions of lung, these results indicate that there is no tendency for the redistribution of ventilation through airways and collateral pathways with changes in VL in young subjects.

Maximal shortening of inspiratory muscles: effect of training

1983 ◽  
Vol 54 (6) ◽  
pp. 1618-1623 ◽  
Author(s):  
C. H. Fanta ◽  
D. E. Leith ◽  
R. Brown
Keyword(s):  
Lung Volume ◽  
Vital Capacity ◽  
Total Lung Capacity ◽  
Training Group ◽  
Normal Subjects ◽  
Pressure Control ◽  
Base Line ◽  
Lung Capacity ◽  
Inspiratory Muscles ◽  
The Mean

Normal subjects can increase their vital capacity by appropriate training. We tested whether that change can be achieved by greater maximal shortening of the inspiratory muscles without concomitant increases in peak static inspiratory pressures. Sixteen healthy volunteers participated in the study: eight were randomly assigned to make 20 inhalations to total lung capacity, held for 10 s with the glottis open, each day for 6 wk; the remainder served as nontraining controls. Before and after the 6-wk study period, we made multiple determinations of lung volumes and of curves relating lung volume to maximal static inspiratory (and expiratory) pressure. Control subjects had no significant changes from base line in any variable. In the training group, the mean vital capacity increased 200 +/- 74 ml (P less than 0.05) or 3.9 +/- 1.3% (P less than 0.02), without a significant change in residual volume. After training, the mean maximal inspiratory pressure at the airway opening (PI) at a lung volume equal to the base-line total lung capacity was 27 +/- 8 cmH2O in this group (vs. zero before training; P less than 0.02). Values of PI in the mid-vital capacity range did not change. We conclude that in response to appropriate training stimuli inspiratory muscles can contract to shorter minimal lengths, a capacity potentially important in progressive pulmonary hyperinflation.

scholarly journals Diaphragm thickening during inspiration

1997 ◽  
Vol 83 (1) ◽  
pp. 291-296 ◽  
Author(s):  
David Cohn ◽  
Joshua O. Benditt ◽  
Scott Eveloff ◽  
F. Dennis McCool
Keyword(s):  
Lung Volume ◽  
Vital Capacity ◽  
Total Lung Capacity ◽  
Diaphragm Thickness ◽  
Lung Volumes ◽  
One Dimensional ◽  
Lung Capacity ◽  
The Mean ◽  
Definition Of ◽  
The Relationship

Cohn, David, Joshua O. Benditt, Scott Eveloff, and F. Dennis McCool. Diaphragm thickening during inspiration. J. Appl. Physiol. 83(1): 291–296, 1997.—Ultrasound has been used to measure diaphragm thickness ( T di) in the area where the diaphragm abuts the rib cage (zone of apposition). However, the degree of diaphragm thickening during inspiration reported as obtained by one-dimensional M-mode ultrasound was greater than that predicted by using other radiographic techniques. Because two-dimensional (2-D) ultrasound provides greater anatomic definition of the diaphragm and neighboring structures, we used this technique to reevaluate the relationship between lung volume and T di. We first established the accuracy and reproducibility of 2-D ultrasound by measuring T diwith a 7.5-MHz transducer in 26 cadavers. We found that T di measured by ultrasound correlated significantly with that measured by ruler ( R 2 = 0.89), with the slope of this relationship approximating a line of identity ( y = 0.89 x + 0.04 mm). The relationship between lung volume and T di was then studied in nine subjects by obtaining diaphragm images at the five target lung volumes [25% increments from residual volume (RV) to total lung capacity (TLC)]. Plots of T di vs. lung volume demonstrated that the diaphragm thickened as lung volume increased, with a more rapid rate of thickening at the higher lung volumes [ T di = 1.74 vital capacity (VC)2 + 0.26 VC + 2.7 mm] ( R 2= 0.99; P < 0.001) where lung volume is expressed as a fraction of VC. The mean increase in T di between RV and TLC for the group was 54% (range 42–78%). We conclude that 2-D ultrasound can accurately measure T di and that the average thickening of the diaphragm when a subject is inhaling from RV to TLC using this technique is in the range of what would be predicted from a 35% shortening of the diaphragm.

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