Effects of rib cage or abdominal restriction on lung mechanics

1981 ◽  
Vol 51 (5) ◽  
pp. 1115-1121 ◽  
Author(s):  
M. Scheidt ◽  
R. E. Hyatt ◽  
K. Rehder
Keyword(s):  
Total Lung Capacity ◽  
Lung Mechanics ◽  
Control Case ◽  
Recoil Pressure ◽  
Rib Cage ◽  
Lung Capacity ◽  
Maximum Expiratory Flow ◽  
The Right ◽  
Volume Decrease ◽  
Healthy Males

The effects on lung mechanics of equal (37%) reduction in total lung capacity (TLC) by rib cage or abdominal restriction were studied in 10 healthy males. Lung recoil pressure (Pst) was simultaneously measured from three sites in the esophagus. This also provided an estimate of the vertical pleural pressure gradient (PPG). Deformation of the right hemithorax was quantified by roentgenograms in three subjects. At the same lung volume, abdominal restriction decreased lung height and increased anteroposterior diameter compared with the control case, whereas rib cage restriction had opposite effects. Maximum expiratory flow increased equally with both types of restriction, and average Pst increased equally with both types of restriction. There was a significant correlation between degree of TLC reduction and increase in Pst that was similar for both types of restriction. This study indicates that changes in lung mechanics depend primarily on the amount of volume reduction and not on the type of deformation producing the volume decrease.

Rib cage and abdominal restrictions have different effects on lung mechanics

1980 ◽  
Vol 49 (6) ◽  
pp. 946-952 ◽  
Author(s):  
C. A. Bradley ◽  
N. R. Anthonisen
Keyword(s):  
Lung Volume ◽  
Total Lung Capacity ◽  
Lung Mechanics ◽  
Elastic Recoil ◽  
Rib Cage ◽  
Lung Capacity ◽  
Single Breath ◽  
Restrictive Procedures ◽  
Maximum Expiratory Flow ◽  
Per Se

The effects of a variety of restrictive procedures on lung mechanics were studied in eight healthy subjects. Rib cage restriction decreased total lung capacity (TLC) by 43% and significantly increased elastic recoil and maximum expiratory flow (MEF). Subsequent immersion of four subjects with rib cage restriction resulted in no further change in either parameter; shifts of blood volume did not reverse recoil changes during rib cage restriction. Abdominal restriction decreased TLC by 40% and increased MEF and elastic recoil, but recoil was increased significantly less than was the case with rib cage restriction. Further, at a given recoil pressure, MEF was less during rib cage restriction than during either abdominal restriction or no restriction. Measurements of the unevenness of inspired gas distribution by the single-breath nitrogen technique showed increased unevenness during rib cage restriction, which was significantly greater than that during abdominal restriction. We conclude that lung volume restriction induces changes in lung function, but the nature of these changes depends on how the restriction is applied and therefore cannot be ascribed to low lung volume breathing per se.

Changes in lung mechanics induced by acute isocapnic hypoxia

1977 ◽  
Vol 42 (3) ◽  
pp. 413-419 ◽  
Author(s):  
N. A. Saunders ◽  
M. F. Betts ◽  
L. D. Pengelly ◽  
A. S. Rebuck
Keyword(s):  
Total Lung Capacity ◽  
Lung Compliance ◽  
Specific Conductance ◽  
Lung Mechanics ◽  
Recoil Pressure ◽  
Lung Capacity ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Residual Capacity ◽  
Dynamic Lung Compliance

We measured lung mechanics in seven healthy males during acute isocapnic hypoxia (PAO2 = 40–50 Torr; PACO2 = 38–42 Torr). Hypoxia was accompanied by increases in total lung capacity (mean increase +/- SD; 0.40 +/- 0.24 liters; P less than 0.005) functional residual capacity (0.34 +/- 0.25 liters; P less than 0.01) and residual volume (0.56 +/- 0.44 liters; P less than 0.02) in all subjects. Specific conductance of the lung decreased during hypoxia (P less than 0.02). The static deflation pressure-volume curve of the lung was shifted upward during hypoxia in all subjects. Resting end-expiratory recoil pressure of the lung was slightly, but not significantly lower during hypoxtic expiratory lung compliance was greater during hypoxia (0.39 +/- 0.04 l/cmH2O) than control measurements (0.31 +/- 0.05 l/cmH2O; P less than 0.005). No change was noted in dynamic lung compliance. All changes in lung mechanics were reversed within three minutes of reoxygenation. We conclude that acute isocapnic hypoxia increases total lung capacity in man and suggest that this may be due to the effect of hypoxia on the airways and pulmonary circulation.

Changes in lung volume and rib cage configuration with abdominal binding in quadriplegia

1986 ◽  
Vol 60 (4) ◽  
pp. 1198-1202 ◽  
Author(s):  
F. D. McCool ◽  
B. M. Pichurko ◽  
A. S. Slutsky ◽  
M. Sarkarati ◽  
A. Rossier ◽  
...  
Keyword(s):  
Total Lung Capacity ◽  
Normal Subjects ◽  
Tidal Range ◽  
Dilution Technique ◽  
Inspiratory Capacity ◽  
Rib Cage ◽  
Lung Capacity ◽  
Residual Capacity ◽  
Helium Dilution ◽  
Combined Data

Previous studies suggest that abdominal binding may affect the interaction of the rib cage and the diaphragm over the tidal range of breathing in quadriplegia. To determine whether abdominal binding influences rib cage motion over the entire range of inspiratory capacity, we used spirometry and the helium-dilution technique to measure functional residual capacity (FRC), inspiratory capacity, and total lung capacity (TLC) in eight quadriplegic and five normal subjects in supine, tilted (37 degrees), and seated positions. Combined data in all three positions indicated that, with abdominal binding, FRC and TLC decreased in normal subjects [delta FRC = -0.33 + 0.151 (SD) P less than 0.01); delta TLC = -0.16 + 0.121, P less than 0.05]. In quadriplegia there was also a reduction in FRC with binding (delta FRC = -0.32 + 0.101, P less than 0.001). However, TLC increased in quadriplegia (delta TLC = 0.07 + 0.061, P less than 0.025). In an additional six quadriplegic and five normal subjects, we used magnetometers to define the influences of abdominal binding on rib cage dimensions and TLC. In quadriplegia, rib cage dimensions were increased at TLC with abdominal binding, whereas there was no change in normals. Our data suggest that this inspiratory effect of abdominal binding on augmenting rib cage volume in quadriplegia is greater than the effect of impeding diaphragm descent, and thus abdominal binding produces a net increase in TLC in quadriplegia.

Respiratory mechanics of a small carnivore: the ferret

1982 ◽  
Vol 52 (4) ◽  
pp. 832-837 ◽  
Author(s):  
A. Vinegar ◽  
E. E. Sinnett ◽  
P. C. Kosch
Keyword(s):  
Total Lung Capacity ◽  
Lung Compliance ◽  
Pulmonary Resistance ◽  
Mustela Putorius ◽  
Tidal Breathing ◽  
Lung Capacity ◽  
Maximum Expiratory Flow ◽  
Residual Capacity ◽  
Dynamic Lung Compliance

The ferret, Mustela putorius furo, is a small relatively inexpensive carnivore with minimal housing requirements. Measurements were made from anesthetized tracheotomized supine males. Values obtained during tidal breathing for six animals (576 +/- 12 g) were as follows: tidal volume, 6.06 +/- 0.30 ml; respiratory frequency, 26.7 +/- 3.9 breaths min-1; dynamic lung compliance, 2.48 +/- 0.21 ml cmH2O-1; pulmonary resistance, 22.56 +/- 1.61 cmH2O . l–1 . s. Pressure-volume curves from nine ferrets revealed almost infinitely compliant chest walls so that lung and total respiratory system curves were essentially the same. Total lung capacity (TLC, 89 +/- 5 ml) and functional residual capacity (17.8 +/- 2.0 ml) were determined by gas freeing the lungs in vivo. The TLC of these ferrets is about the same as in 2.5-kg rabbits. Maximum expiratory flow-volume curves showed peak flows of 10.1 vital capacities (VC) . s-1 at 75% VC and flows of 8.4 and 5.4 VC . s-1 at 50 and 25% VC.

Temperature and surface forces in excised rabbit lungs

1981 ◽  
Vol 51 (4) ◽  
pp. 823-829 ◽  
Author(s):  
H. Inoue ◽  
C. Inoue ◽  
J. Hildebrandt
Keyword(s):  
Total Lung Capacity ◽  
Peak Pressure ◽  
Surface Forces ◽  
Temperature Changes ◽  
Lung Capacity ◽  
Lung Expansion ◽  
Rigid Lining ◽  
Effects Of Temperature ◽  
The Right ◽  
Gas Volume

This study was designed to determine whether the effects of temperature on lung pressure-volume (PV) curves were influenced by the state of the surface lining at the time of warming or cooling. In successive runs, temperature was varied (21, 37, or 5 degrees C) with lung gas volume fixed at either 55% total lung capacity (TLC) or 0% TLC (degassed), followed by PV curves to TLC. Peak inflation volume in a given lung was made identical at all temperatures. The starting pressure at 55% TLC remained fixed during temperature changes, whereas peak pressure ranged from 24 cmH2O at 37 degrees C to 40 cmH2O at 5 degrees C. However, below 75% TLC all deflation curves differed by less than 1 cmH2O, and the lowest recoil occurred at 5 degrees C. At 0% TLC, a similar dispersion in pressures appeared at TLC. However, on deflation, recoil at 37 degrees C was always less than at 21 degrees C, whereas at 5 degrees C a drastic shift to the right occurred. First-cycle hysteresis and midinflation pressure also increased with cooling. Thus, with cooling, the spreading and adsorption of surfactant during lung expansion are inhibited, and during deflation aggregation is greatly facilitated, accounting for the above results. When an already spread surface is cooled, then expanded, as at 55% TLC, the more rigid lining causes some rise in peak pressure at TLC but little change elsewhere. However, when lungs are degassed and then cooled, the aggregated surfactant spreads extremely poorly, leading to greatly increased recoil throughout the cycle. Changes in pressure at TLC may depend considerably on tissue effects.

scholarly journals Blunted perception of neural respiratory drive and breathlessness in patients with cystic fibrosis

2016 ◽  
Vol 2 (1) ◽  
pp. 00057-2015 ◽  
Author(s):  
Charles C. Reilly ◽  
Caroline J. Jolley ◽  
Caroline Elston ◽  
John Moxham ◽  
Gerrard F. Rafferty
Keyword(s):  
Cystic Fibrosis ◽  
Total Lung Capacity ◽  
Forced Expiratory Volume ◽  
Respiratory Drive ◽  
Healthy Individuals ◽  
Surface Electrodes ◽  
Lung Capacity ◽  
Clinically Significant ◽  
The Right ◽  
The Relationship

The electromyogram recorded from the diaphragm (EMGdi) and parasternal intercostal muscle using surface electrodes (sEMGpara) provides a measure of neural respiratory drive (NRD), the magnitude of which reflects lung disease severity in stable cystic fibrosis. The aim of this study was to explore perception of NRD and breathlessness in both healthy individuals and patients with cystic fibrosis. Given chronic respiratory loading and increased NRD in cystic fibrosis, often in the absence of breathlessness at rest, we hypothesised that patients with cystic fibrosis would be able to tolerate higher levels of NRD for a given level of breathlessness compared to healthy individuals during exercise.15 cystic fibrosis patients (mean forced expiratory volume in 1 s (FEV1) 53.5% predicted) and 15 age-matched, healthy controls were studied. Spirometry was measured in all subjects and lung volumes measured in the cystic fibrosis patients. EMGdi and sEMGpara were recorded at rest and during incremental cycle exercise to exhaustion and expressed as a percentage of maximum (% max) obtained from maximum respiratory manoeuvres. Borg breathlessness scores were recorded at rest and during each minute of exercise.EMGdi % max and sEMGpara % max and associated Borg breathlessness scores differed significantly between healthy subjects and cystic fibrosis patients at rest and during exercise. The relationship between EMGdi % max and sEMGpara % max and Borg score was shifted to the right in the cystic fibrosis patients, such that at comparable levels of EMGdi % max and sEMGpara % max the cystic fibrosis patients reported significantly lower Borg breathlessness scores compared to the healthy individuals. At Borg score 1 (clinically significant increase in breathlessness from baseline) corresponding levels of EMGdi % max (20.2±12% versus 32.15±15%, p=0.02) and sEMGpara % max (18.9±8% versus 29.2±15%, p=0.04) were lower in the healthy individuals compared to the cystic fibrosis patients.In the cystic fibrosis patients EMGdi % max at Borg score 1 was related to the degree of airways obstruction (FEV1) (r=−0.664, p=0.007) and hyperinflation (residual volume/total lung capacity) (r=0.710, p=0.03). This relationship was not observed for sEMGpara % max.These data suggest that compared to healthy individuals, patients with cystic fibrosis can tolerate much higher levels of NRD before increases in breathlessness from baseline become clinically significant. EMGdi % max and sEMGpara % max provide physiological tools with which to elucidate factors underlying inter-individual differences in breathlessness perception.

Effects of posture on respiratory mechanics in obesity

1995 ◽  
Vol 79 (4) ◽  
pp. 1199-1205 ◽  
Author(s):  
J. C. Yap ◽  
R. A. Watson ◽  
S. Gilbey ◽  
N. B. Pride
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Respiratory Mechanics ◽  
Total Lung Capacity ◽  
Abdominal Mass ◽  
Lung Capacity ◽  
Supine Posture ◽  
Maximum Expiratory Flow ◽  
Maximum Effort ◽  
Residual Capacity

Increased abdominal mass in obesity should enhance normal gravitational effects on supine respiratory mechanics. We have examined respiratory impedance (forced oscillation over 4–26 Hz applied at the mouth during tidal breathing), maximum inspiratory and expiratory mouth pressures (MIP and MEP), and maximum effort flow-volume curves seated and supine in seven obese subjects (O) (mean age 51 yr, body mass index 43.6 kg/m2) and seven control subjects (C) (mean age 50 yr, body mass index 21.8 kg/m2). Seated mean total lung capacity was smaller in O than in C (82 vs. 100% of predicted); ratio of functional residual capacity (FRC) to total lung capacity averaged 43% in O and 61% in C (P < 0.01). Total respiratory resistance (Rrs) at 6 Hz seated was higher in O (4.6 cmH2O.l-1.s) than in C (2.2 cmH2O.l-1.s; P < 0.001); total respiratory reactance (Xrs) at 6 Hz was lower in O than in C. In C, on changing to the supine posture, mean Rrs at 6 Hz rose to 2.9 cmH2O.l-1.s, FRC fell by 0.68 liter, and Xrs at 6 Hz showed a small fall. In O, despite no further fall in FRC, supine Rrs at 6 Hz increased to 7.3 cmH2O.l-1.s, and marked frequency dependency of Rrs and falls in Xrs developed. Seated, MIP and MEP in C and O were similar; supine there were small falls in MEP and maximum expiratory flow in O. The site and mechanism of the increase in supine Rrs and reduction in supine Xrs and the mechanism maintaining supine FRC in obesity all need further investigation.

Lung mechanics following aspiration of 0.1 N hydrochloric acid

1983 ◽  
Vol 55 (4) ◽  
pp. 1051-1056 ◽  
Author(s):  
R. Winn ◽  
J. Stothert ◽  
B. Nadir ◽  
J. Hildebrandt
Keyword(s):  
Body Weight ◽  
Hydrochloric Acid ◽  
Airway Obstruction ◽  
Total Lung Capacity ◽  
Transpulmonary Pressure ◽  
Surface Forces ◽  
Lung Mechanics ◽  
Lung Water ◽  
Lung Capacity ◽  
Air Volume

Pressure-volume curves were obtained from excised left lungs of goats at 4, 24, and 48 h after tracheal instillation of 2.5 ml/kg of 0.1 N HCl. Air total lung capacity (TLC) at transpulmonary pressure (PL) = 35 cmH2O was 38.8 ml/kg body weight before acid, and was reduced sharply to 21.1 at 4 h, then increased to 25.6 at 24 h and 32.1 at 48 h. Excess extravascular lung water (EVLW) could account for only part of the volume reductions. Specific compliance ratio of transpulmonary pressure to total lung capacity (CL/TLC) between PL of 5 and 0 cmH2O was reduced from 0.074/cmH2O to 0.050, 0.048, and 0.053/cmH2O, respectively. Saline TLC (PL = 10 cmH2O) changed from 44.8 to 32.4, 34.3, and 45.4 ml/kg, respectively, but CL/TLC did not, suggesting airway obstruction. After injury, trapped volume at PL = 0 increased from 24.9 to 29.2, 43.3, and 37.3% TLC with air, and from 20.3 to 38.5, 33.1, and 28.5%, respectively, with saline. Air volume at a PL = 10 cmH2O on deflation fell from 82.0 to 72.1% TLC at 4 h, but was near control at 24 and 48 h. The reduction in ventilated volume was not reflected in proportionately increased shunt; therefore, some compensatory vasoconstriction must have occurred. We suggest that in affected regions increased surface forces, increased EVLW, and airway obstruction caused reductions of lung volume.

Changes in lung, airway, and chest wall function in boys and girls between 8 and 12 yr

1984 ◽  
Vol 57 (2) ◽  
pp. 304-308 ◽  
Author(s):  
M. E. Hibbert ◽  
J. M. Couriel ◽  
L. I. Landau
Keyword(s):  
Chest Wall ◽  
School Children ◽  
Total Lung Capacity ◽  
Residual Volume ◽  
Wall Function ◽  
Lung Volumes ◽  
Lung Capacity ◽  
Maximum Expiratory Flow ◽  
Lower Maximum ◽  
The Difference

Maximum expiratory flows, maximum inspiratory and expiratory pressures, and lung volumes were measured in 248 8-yr-old and 215 12-yr-old healthy school children. Eight-year-old girls had smaller total lung capacity but higher volume-corrected expiratory flows than boys. Maximum expiratory flow and total lung capacity increased more in girls than in boys between 8 and 12 yr. Girls had a greater increase in residual volume (0.23 liter for girls, 0.16 liter for boys) as well as lower maximum expiratory and inspiratory pressures (P less than 0.001). Girls have smaller lung volumes than boys, so one would expect smaller airways in girls, but girls generate greater flows, indicating that their airways are possibly wider than those of boys. There is also evidence of unequal growth of the airways and air spaces between 8 and 12 yr. Chest wall development appears less in girls than boys and the difference becomes more marked at 12 yr.

Aerosol probes of lung injury in a 28-wk longitudinal study of mild experimental emphysema in dogs

1999 ◽  
Vol 86 (2) ◽  
pp. 725-731 ◽  
Author(s):  
Frank S. Rosenthal
Keyword(s):  
Lung Injury ◽  
Total Lung Capacity ◽  
Lung Mechanics ◽  
Partial Recovery ◽  
Lung Capacity ◽  
Air Space ◽  
Aerosol Dispersion ◽  
Increasing Trends ◽  
Experimental Emphysema

After baseline measurements of lung mechanics, effective air space diameter (EAD), and aerosol dispersion (AD), three dogs were exposed to two treatments of aerosolized papain (3 ml of a 4% solution), and measurements were repeated during a 28-wk follow-up period. EAD and AD were measured with boluses of 0.7-μm particles of di-2-ethylhexl sebacate, with Pen (i.e., volumetric bolus penetration/total lung capacity) between 0.1 and 0.4. After papain exposure, EAD increased a mean of 28% ( P < 0.0001) and AD (Pen = 0.3, 0.4) increased 4–7% ( P < 0.03). The progression of injury was indicated by increasing trends in total lung capacity ( P < 0.05), residual volume ( P < 0.05), and EAD ( P = 0.06) through week 18. There was no evidence of disease progression between weeks 18and 28, whereas some of the data for individual dogs suggested partial recovery from lung injury at week 28. The results show that aerosol probes can detect and characterize mild lung injury in experimental emphysema.

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