Mechanism of action of ozone on the human lung

1989 ◽  
Vol 67 (4) ◽  
pp. 1535-1541 ◽  
Author(s):  
M. J. Hazucha ◽  
D. V. Bates ◽  
P. A. Bromberg
Keyword(s):  
Functional Residual Capacity ◽  
Airway Resistance ◽  
Transpulmonary Pressure ◽  
Dynamic Compliance ◽  
Exposure Period ◽  
Pulmonary Mechanics ◽  
Residual Volume ◽  
Residual Capacity ◽  
Controlled Exposure ◽  
Change Dynamic

Fourteen healthy normal volunteers were randomly exposed to air and 0.5 ppm of ozone (O3) in a controlled exposure chamber for a 2-h period during which 15 min of treadmill exercise sufficient to produce a ventilation of approximately 40 l/min was alternated with 15-min rest periods. Before testing an esophageal balloon was inserted, and lung volumes, flow rates, maximal inspiratory (at residual volume and functional residual capacity) and expiratory (at total lung capacity and functional residual capacity) mouth pressures, and pulmonary mechanics (static and dynamic compliance and airway resistance) were measured before and immediately after the exposure period. After the postexposure measurements had been completed, the subjects inhaled an aerosol of 20% lidocaine until response to citric acid aerosol inhalation was abolished. All of the measurements were immediately repeated. We found that the O3 exposure 1) induced a significant mean decrement of 17.8% in vital capacity (this change was the result of a marked fall in inspiratory capacity without significant increase in residual volume), 2) significantly increased mean airway resistance and specific airway resistance but did not change dynamic or static pulmonary compliance or viscous or elastic work, 3) significantly reduced maximal transpulmonary pressure (by 19%) but produced no changes in inspiratory or expiratory maximal mouth pressures, and 4) significantly increased respiratory rate (in 5 subjects by more than 6 breaths/min) and decreased tidal volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in compliance in rabbits subjected to acute bronchoconstriction

1963 ◽  
Vol 18 (3) ◽  
pp. 539-543 ◽  
Author(s):  
Nicholas R. Anthonisen
Keyword(s):  
Functional Residual Capacity ◽  
Pulmonary Circulation ◽  
Dynamic Compliance ◽  
Pulmonary Mechanics ◽  
Static Compliance ◽  
Airway Occlusion ◽  
Random Direction ◽  
Residual Capacity ◽  
Spontaneously Breathing ◽  
Phrenic Stimulation

The pulmonary mechanics of anesthetized rabbits were studied during induced acute bronchoconstriction. The bronchoconstricting agent was acetyl-β-methylcholine which, when injected intravenously as in these experiments, appeared to act via the pulmonary circulation. In spontaneously breathing animals functional residual capacity increased with bronchospasm, and dynamic compliance decreased. This decrease correlated in magnitude with the severity of the bronchoconstriction. Frequency changed in random direction. Dynamic compliance recovered more slowly than conductance after bronchoconstriction unless the lungs were inflated just prior to each recovery measurement, in which case the two variables recovered equally quickly. This observation suggested that airway occlusion accounted for part of the decrease in dynamic compliance. Bronchoconstriction reduced semistatic compliance in paralyzed artificially ventilated animals and also static compliance, which was measured by arresting breathing with phrenic stimulation, in spontaneously breathing animals. These observations supported the above hypothesis. Submitted on September 26, 1962

Effect of ventilatory frequency on regional transpulmonary pressure in normal adults

1981 ◽  
Vol 51 (3) ◽  
pp. 678-685 ◽  
Author(s):  
W. Hida ◽  
S. Suzuki ◽  
H. Sasaki ◽  
Y. Fujii ◽  
T. Sasaki ◽  
...  
Keyword(s):  
Balloon Catheter ◽  
Transpulmonary Pressure ◽  
Dynamic Compliance ◽  
Local Dynamic ◽  
Ventilatory Frequency ◽  
Catheter System ◽  
Residual Capacity ◽  
Resistive Component ◽  
Normal Adults ◽  
Zero Frequency

The relation between the ventilatory frequency and the elastic (delta Pel) or resistive (delta Prs) components of changes of the regional pleural pressure (delta PL) was studied at functional residual capacity (FRC) in six normal adults. The regional delta PL was measured simultaneously at three levels in the esophagus using a three-balloon-catheter system. Elastic components of regional delta PL normalized by overall tidal volume (delta Pel/delta V) increased with frequency at all three balloon positions; the percentages of delta Pel/delta V at 60 breaths/min to those at zero frequency were 107, 119, and 157% in the upper, middle, and lower balloon, respectively. The resistive component of regional delta PL normalized by overall air flow (delta Prs/delta V) did not show significant dependence on frequency at any of the three positions and was almost the same everywhere. It is suggested that the increase of local delta Pel with frequency might reflect mainly the frequency dependence of local dynamic compliance (Cdyn) and that the change of the local Cdyn with frequency might be larger in dependent than in upper lung.

Minimal air in dogs

1964 ◽  
Vol 19 (2) ◽  
pp. 204-206 ◽  
Author(s):  
Leonard I. Kleinman ◽  
Dennis A. Poulos ◽  
Arthur A. Siebens
Keyword(s):  
Correlation Coefficient ◽  
Functional Residual Capacity ◽  
Residual Volume ◽  
Lung Weight ◽  
Volume Functional ◽  
Residual Capacity

The “minimal air” of supine dogs was measured by subtracting from the functional residual capacity the volume expelled from the lungs when the sternum was widely split. Minimal air/functional residual capacity, minimal air/lung weight, and minimal air/animal weight were 57.0 ± 8.6%, 9.51 ± 2.92 ml/g, 21.8 ± 4.2 ml/kg, respectively. The correlation coefficient of minimal air with functional residual capacity was .79 (P < 1%), of minimal air with animal weight was 0.70 (P < 1%), and of minimal air with lung weight was .67 (P < 5%). The ratio minimal air/functional residual capacity of these dogs compared with the ratio residual volume/functional residual capacity of supine men. The airway component of the minimal air was approximately 36% and the alveolar component approximately 64%. The lungs contained the minimal air at a time when airways were patent rather than collapsed. functional residual capacity; residual volume Submitted on March 11, 1963

Pulmonary mechanics during rapid mechanical ventilation in rabbits with saline-lavaged lungs

1986 ◽  
Vol 61 (4) ◽  
pp. 1431-1437 ◽  
Author(s):  
J. J. Perez Fontan ◽  
B. S. Turner ◽  
G. P. Heldt ◽  
G. A. Gregory
Keyword(s):  
Tidal Volume ◽  
Gas Flow ◽  
Transpulmonary Pressure ◽  
Inspiratory Flow ◽  
Pulmonary Mechanics ◽  
Mechanically Ventilated ◽  
Ventilatory Rate ◽  
Residual Capacity ◽  
Pressure Volume Relationship ◽  
Linear Ramp

Infants with respiratory failure are frequently mechanically ventilated at rates exceeding 60 breaths/min. We analyzed the effect of ventilatory rates of 30, 60, and 90 breaths/min (inspiratory times of 0.6, 0.3, and 0.2 s, respectively) on the pressure-flow relationships of the lungs of anesthetized paralyzed rabbits after saline lavage. Tidal volume and functional residual capacity were maintained constant. We computed effective inspiratory and expiratory resistance and compliance of the lungs by dividing changes in transpulmonary pressure into resistive and elastic components with a multiple linear regression. We found that mean pulmonary resistance was lower at higher ventilatory rates, while pulmonary compliance was independent of ventilatory rate. The transpulmonary pressure developed by the ventilator during inspiration approximated a linear ramp. Gas flow became constant and the pressure-volume relationship linear during the last portion of inspiration. Even at a ventilatory rate of 90 breaths/min, 28–56% of the tidal volume was delivered with a constant inspiratory flow. Our findings are consistent with the model of Bates et al. (J. Appl. Physiol. 58: 1840–1848, 1985), wherein the distribution of gas flow within the lungs depends predominantly on resistive factors while inspiratory flow is increasing, and on elastic factors while inspiratory flow is constant. This dynamic behavior of the surfactant-depleted lungs suggests that, even with very short inspiratory times, distribution of gas flow within the lungs is in large part determined by elastic factors. Unless the inspiratory time is further shortened, gas flow may be directed to areas of increased resistance, resulting in hyperinflation and barotrauma.

Effect of artificial surfactant on pulmonary function in preterm and full-term lambs

1990 ◽  
Vol 69 (2) ◽  
pp. 465-472 ◽  
Author(s):  
I. M. Gladstone ◽  
A. O. Ray ◽  
C. M. Salafia ◽  
J. Perez-Fontan ◽  
M. R. Mercurio ◽  
...  
Keyword(s):  
Surface Tension ◽  
Functional Residual Capacity ◽  
Dynamic Compliance ◽  
Full Term ◽  
Tween 20 ◽  
Minimum Surface ◽  
Natural Surfactant ◽  
Equilibrium Surface Tension ◽  
Lung Expansion ◽  
Residual Capacity

We hypothesized that agents very different from surfactant may still support lung function. To test this hypothesis, we instilled FC-100, a fluorocarbon, and Tween 20, a detergent, which have higher minimum surface tensions and less hysteresis than surfactant, into 15 full-term and 14 preterm lambs. FC-100 and Tween 20 were as efficient as natural surfactant in improving gas exchange and compliance in preterm lambs with respiratory failure. Dynamic compliance correlated with the equilibrium surface tension of the alveolar wash in both full-term (P less than 0.02) and preterm (P less than 0.008) lambs. Functional residual capacity in full-term and preterm lambs was lower after treatment with the two test agents than with surfactant, findings consistent with qualitative histology. Oxygenation in full-term lambs correlated with mean lung volumes (P less than 0.003), suggesting that the hysteresis and/or low minimum surface tension of surfactant may improve mean lung volume, and hence oxygenation, by maintaining functional residual capacity. The effects of the test agents suggest that agents with biophysical properties different from surfactant may still aid lung expansion.

Respiratory changes in diaphragmatic intramuscular pressure

1990 ◽  
Vol 68 (1) ◽  
pp. 35-43 ◽  
Author(s):  
M. Decramer ◽  
T. X. Jiang ◽  
M. B. Reid
Keyword(s):  
Functional Residual Capacity ◽  
Total Lung Capacity ◽  
Residual Volume ◽  
Intramuscular Pressure ◽  
Phrenic Nerve Stimulation ◽  
Direct Stimulation ◽  
Lung Capacity ◽  
Residual Capacity ◽  
Anesthetized Dogs ◽  
Stimulation Of

We attempted to measure diaphragmatic tension by measuring changes in diaphragmatic intramuscular pressure (Pim) in the costal and crural parts of the diaphragm in 10 supine anesthetized dogs with Gaeltec 12 CT minitransducers. During phrenic nerve stimulation or direct stimulation of the costal and crural parts of the diaphragm in an animal with the chest and abdomen open, Pim invariably increased and a linear relationship between Pim and the force exerted on the central tendon was found (r greater than or equal to 0.93). During quiet inspiration Pim in general decreased in the costal part (-3.9 +/- 3.3 cmH2O), whereas it either increased or slightly decreased in the crural part (+3.3 +/- 9.4 cmH2O, P less than 0.05). Similar differences were obtained during loaded and occluded inspiration. After bilateral phrenicotomy Pim invariably decreased during inspiration in both parts (costal -4.3 +/- 6.4 cmH2O, crural -3.1 +/- 0.6 cmH2O). Contrary to the expected changes in tension in the muscle, but in conformity with the pressure applied to the muscle, Pim invariably increased during passive inflation from functional residual capacity to total lung capacity (costal +30 +/- 23 cmH2O, crural +18 +/- 18 cmH2O). Similarly, during passive deflation from functional residual capacity to residual volume, Pim invariably decreased (costal -12 +/- 19 cmH2O, crural -12 +/- 14 cmH2O). In two experiments similar observations were made with saline-filled catheters. We conclude that although Pim increases during contraction as in other muscles, Pim during respiratory maneuvers is primarily determined by the pleural and abdominal pressures applied to the muscle rather than by the tension developed by it.

Airway closure during anesthesia: a comparison between resident-gas and argon-bolus techniques

1979 ◽  
Vol 47 (4) ◽  
pp. 874-881 ◽  
Author(s):  
G. Hedenstierna ◽  
J. Santesson
Keyword(s):  
Functional Residual Capacity ◽  
Lung Volume ◽  
Healthy Subjects ◽  
Abrupt Onset ◽  
Closing Volume ◽  
Residual Volume ◽  
Airway Closure ◽  
Venous Admixture ◽  
Residual Capacity ◽  
Nitrogen Concentrations

Airway closure was measured in awake and then anesthetized supine healthy subjects with the argon-bolus and the resident-gas (nitrogen) techniques simultaneously. The preinspiratory lung volume for the closing volume maneuver was varied from residual volume to closing capacity (CC). Comparative measurements were also performed in the upright and supine positions in awake subjects. Closing volume (CV) was consistently larger with the bolus technique in supine subjects both when awake and when anesthetized (difference between methods 0.1--0.2 l, P less than 0.01), whereas no difference between the methods was noted in upright subjects. The lower “nitrogen CV” in supine subjects may be due to a shorter vertical lung height with a smaller range of nitrogen concentrations, resulting in a less abrupt onset of phase IV (taken to indicate CV). CV was not significantly affected by the preinspiratory lung volume with either technique, and CC was unchanged when anesthesia was instituted. Functional residual capacity (FRC) was reduced with anesthesia (mean reduction: 0.6 l, P less than 0.01) and FRC-CC became negative in all subjects with either technique. This implies intermittent or continuous airway closure during anesthesia and the possibility of increased venous admixture.

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