Pulmonary mechanics during exercise in normal males

1980 ◽  
Vol 49 (3) ◽  
pp. 506-510 ◽  
Author(s):  
D. G. Stubbing ◽  
L. D. Pengelly ◽  
J. L. Morse ◽  
N. L. Jones
Keyword(s):  
Transpulmonary Pressure ◽  
Progressive Increase ◽  
Cycle Ergometer ◽  
Pulmonary Mechanics ◽  
Normal Male ◽  
Tidal Breathing ◽  
Control Value ◽  
Pulmonary Compliance ◽  
Capillary Blood Volume ◽  
Residual Capacity

A body plethysmograph adapted to contain the pedals of an electrically braked cycle ergometer was used to measure pulmonary mechanics during steady-state exercise in 12 normal male subjects aged 22-65 yr. During exercise there was a progressive increase in residual volume to 119% of the value at rest (P less than 0.01), but functional residual capacity and total lung capacity did not change. The maximum expiratory flow-volume (MEFV) curves did not change and flow rates during tidal breathing did not exceed the MEFV curve. Dynamic pulmonary compliance fell to 91.3% of the control value and static expiratory pulmonary compliance fell to 76.9% of the control value (P less than 0.05). Pulmonary resistance did not change during exercise. Transpulmonary pressure during tidal breathing was negative even at the highest power outputs. The fall in compliance may be due to an increase in pulmonary capillary blood volume. These results demonstrate the importance of measuring absolute thoracic gas volume and the elastic properties of the lung when comparing pulmonary mechanics at rest and during exercise.

Pulmonary mechanics during exercise in subjects with chronic airflow obstruction

1980 ◽  
Vol 49 (3) ◽  
pp. 511-515 ◽  
Author(s):  
D. G. Stubbing ◽  
L. D. Pengelly ◽  
J. L. Morse ◽  
N. L. Jones
Keyword(s):  
Tidal Flow ◽  
Airflow Obstruction ◽  
Maximum Flow ◽  
Transpulmonary Pressure ◽  
Pulmonary Mechanics ◽  
Flow Volume ◽  
Tidal Breathing ◽  
Flow Rates ◽  
Control Value ◽  
Expiratory Flow

A body plethysmograph was used to measure pulmonary mechanics in six subjects with chronic airflow obstruction during steady states at rest and during exercise at 200 and 400 kpm . min-1. The mean forced expired volume in 1 s was 1.32 liters (39.2% predicted). The flow rates during tidal breathing reached the maximum expiratory flow-volume (MEFV) curve in all but one subject, and on exercise they all reached the MEFV curve. Total lung capacity did not change significantly, but functional residual capacity increased to 104% of the control value (P less than 0.05) and residual volume increased to 113.3% of the control value (P less than 0.02). The MEFV curves did not change and tidal flow rates in excess of th MEFV curve were not seen. Dynamic compliance fell with increasing exercise to 52.8% (P less than 0.01) and static expiratory pulmonary compliance to 90.2% of the control value. Transpulmonary pressures during tidal breathing when expiratory flow reached the MEFV curve increased to progressively higher values as the work load increased. At low work loads there were several subjects with negative transpulmonary pressure when maximum flow rates were present. In patients with chronic airflow obstruction, little change occurs during exercise in pulmonary mechanics; the tidal flow patterns are dominated by the expired flow-volume curve, which is not changed by exercise; maximum flow occurs in some patients when transpulmonary pressure is still negative.

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.

Volume of activation of the Hering-Breuer inflation reflex in the newborn infant

2001 ◽  
Vol 90 (3) ◽  
pp. 763-769 ◽  
Author(s):  
A. Hassan ◽  
J. Gossage ◽  
D. Ingram ◽  
S. Lee ◽  
A. D. Milner
Keyword(s):  
Lung Volume ◽  
Polynomial Regression ◽  
Neonatal Period ◽  
Face Mask ◽  
Progressive Increase ◽  
Inspiratory Time ◽  
Tidal Breathing ◽  
Expiratory Time ◽  
Healthy Infants ◽  
Residual Capacity

Although the Hering-Breuer inflation reflex (HBIR) is active within tidal breathing range in the neonatal period, there is no information regarding whether a critical volume has to be exceeded before any effect can be observed. To explore this, effects of multiple airway occlusions on inspiratory and expiratory timing were measured throughout tidal breathing range using a face mask and shutter system. In 20 of the 22 healthy infants studied, there was significant shortening of inspiration because the volume at which occlusion occurred rose from functional residual capacity (FRC) to end-inspiratory volume [14.9% reduction in inspiratory time (per ml/kg increase in lung volume at occlusion)]. All infants showed a significant increase in expiratory time [17.1% increase (per ml/kg increase in lung volume at occlusion)]. Polynomial regression analyses revealed a progressive increase in strength of HBIR from FRC to ∼4 ml/kg above FRC. Eighteen infants showed no further shortening of inspiratory time and 10 infants no further lengthening of expiratory time with increasing occlusion volumes, indicating maximal stimulation of the reflex had been achieved. There was a significant relationship between strength of HBIR and respiratory rate, suggesting that HBIR modifies the breathing pattern in the neonatal period.

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)

Airway reactivity in infants: a positive response to methacholine and metaproterenol

1987 ◽  
Vol 62 (3) ◽  
pp. 1155-1159 ◽  
Author(s):  
R. S. Tepper
Keyword(s):  
Challenge Test ◽  
Threshold Concentration ◽  
Base Line ◽  
Tidal Breathing ◽  
Airway Reactivity ◽  
Bronchial Smooth Muscle ◽  
Bronchial Challenge ◽  
Control Value ◽  
Residual Capacity ◽  
The Mean

Because the presence of bronchial smooth muscle reactivity in infants remains controversial, airway reactivity was assessed in 10 normal, asymptomatic male infants less than 15 mo of age by measuring the changes that occurred in the maximal expiratory flows at functional residual capacity (VmaxFRC) during a methacholine bronchial challenge test. Sleeping infants inhaled doubling concentrations of methacholine by 2 min of tidal breathing, starting with a concentration of 0.075 mg/ml, and the bronchial challenge was stopped when VmaxFRC decreased by at least 40%. The threshold concentration of methacholine required to produce a decrease in VmaxFRC by 2 SD's of the control value was 0.43 mg/ml (0.11–0.90). By a methacholine concentration of 1.2 mg/ml, all infants decreased VmaxFRC by at least 40% (range 40–75%), and the mean dose required to produce a 40% decrease was 0.72 mg/ml. The airway reactivity was not related to base-line flows. During the methacholine challenge, no infant developed wheezing, but the percent oxygen saturation for the group decreased significantly (P less than 0.05) from 94 to 92%. Following the methacholine, the infants inhaled the bronchodilator metaproterenol, and 10 min later, VmaxFRC returned to base line. This study demonstrates that infants exhibit airway reactivity as evidenced by bronchoconstriction with methacholine and the subsequent bronchodilation with metaproterenol.

Effect of acute alterations of blood volume on circulatory performance in humans

1981 ◽  
Vol 50 (2) ◽  
pp. 292-298 ◽  
Author(s):  
S. M. Fortney ◽  
E. R. Nadel ◽  
C. B. Wenger ◽  
J. R. Bove
Keyword(s):  
Bacterial Pneumonia ◽  
Pneumococcal Pneumonia ◽  
Total Lung Capacity ◽  
Lower Lobe ◽  
Pulmonary Mechanics ◽  
Tidal Breathing ◽  
Initial Value ◽  
Lung Capacity ◽  
Residual Capacity ◽  
Gas Volume

We produced left lower lobe (LLL) pneumococcal pneumonia in seven dogs and measured lung volumes and pulmonary mechanics before (day 1) and 48 h after (day 3) development of the infection. Compared with seven control dogs, total lung capacity (TLC) and functional residual capacity (FRC) decreased 550 and 140 ml, respectively, representing a 15% reduction from the initial value in both cases. Compliance measured during tidal breathing decreased by 30%, and even when corrected for the smaller FRC on day 3, specific compliance (CLsp) was reduced. At autopsy, the infected LLL had an excess weight of 89 g, and its 50% reduction in gas volume accounted for the decrease in TLC from day 1 to day 3. Compared with control dogs, there were no changes in the deflation pressure-volume curves of the noninfected lung of the pneumonia dogs. These results indicate that the reduction in TLC in bacterial lobar pneumonia was small and resulted from the reduced gas volume of the infected lobe. Assuming that the increased weight gain in the LLL represented 89 ml of exudate that filled alveoli, we propose that bacterial pneumonia reduced gas volume at FRC by filling alveoli with inflammatory exudate and further decreased TLC by preventing these alveoli from inflating. The reduced CLsp suggested nonventilation of air spaces in addition to those that were liquid filled and was consistent with nonventilation of the entire LLL.

Effect of pneumococcal lobar pneumonia on canine lung mechanics

1981 ◽  
Vol 50 (2) ◽  
pp. 283-291 ◽  
Author(s):  
S. N. Mink ◽  
R. B. Light ◽  
L. D. Wood
Keyword(s):  
Total Lung Capacity ◽  
Lower Lobe ◽  
Lung Mechanics ◽  
Pulmonary Mechanics ◽  
Tidal Breathing ◽  
Initial Value ◽  
Lobar Pneumonia ◽  
Lung Capacity ◽  
Residual Capacity ◽  
Gas Volume

We produced left lower lobe (LLL) pneumococcal pneumonia in seven dogs and measured lung volumes and pulmonary mechanics before (day 1) and 48 h after (day 3) development of the infection. Compared with seven control dogs, total lung capacity (TLC) and functional residual capacity (FRC) decreased 550 and 140 ml, respectively, representing a 15% reduction from the initial value in both cases. Compliance measured during tidal breathing decreased by 30%, and even when corrected for the smaller FRC on day 3, specific compliance (CLsp) was reduced. At autopsy, the infected LLL had an excess weight of 89 g, and its 50% reduction in gas volume accounted for the decrease in TLC from day 1 to day 3. Compared with control dogs, there were no changes in the deflation pressure-volume curves of the noninfected lung of the pneumonia dogs. These results indicate that the reduction in TLC in bacterial lobar pneumonia was small and resulted from the reduced gas volume of the infected lobe. Assuming that the increased weight gain in the LLL represented 89 ml of exudate that filled alveoli, we propose that bacterial pneumonia reduced gas volume at FRC by filling alveoli with inflammatory exudate and further decreased TLC by preventing these alveoli from inflating. The reduced CLsp suggested nonventilation of air spaces in addition to those that were liquid filled and was consistent with nonventilation of the entire LLL.

Effect of interstitial fluid (kerosene) on pressure-volume characteristics of rat lung

1982 ◽  
Vol 52 (1) ◽  
pp. 260-266 ◽  
Author(s):  
W. F. Urmey ◽  
S. M. Scharf ◽  
R. Brown ◽  
D. Carlson ◽  
P. Song
Keyword(s):  
Interstitial Fluid ◽  
Transpulmonary Pressure ◽  
Progressive Increase ◽  
Rat Lung ◽  
Interstitial Edema ◽  
Maximal Volume ◽  
Air Volume ◽  
Lung Expansion ◽  
Volume Characteristics ◽  
Alveolar Edema

Although pulmonary interstitial edema has been estimated to decrease pulmonary compliance (CL), it has been experimentally difficult to demonstrate whether the observed changes in CL are directly due to the presence of interstitial fluid or if they result instead from concomitant pulmonary vascular engorgement and/or alveolar edema. Since kerosene-inflated lungs do not leak, we were able to use kerosene to measure the effect on CL of the accumulation of interstitial fluid (kerosene) in the postmortem rat lung. Pressure-volume (PV) studies of the lung were done during the progressive increase in interstitial fluid (kerosene). Analysis of the deflation limbs of the quasistatic PV curves obtained following serial inflations with kerosene indicated that the maximal volume of kerosene [MV35, equal to the maximum tissue plus airway volume at a transpulmonary pressure (Ptp) of 35 cmH2O] was 3.8 +/- 1.2 ml (31.0 +/- 11.8%) greater than TLC35 [air volume at Ptp of 35 cmH2O prior to kerosene inflation]. The increases in interstitial kerosene volume had no effect on kerosene PV characteristics, as was demonstrated by superimposing lung PV curves obtained at various states of interstitial filling. We conclude that the interstitial compartment is large and very compliant and that the presence of even great amounts of fluid limited to this compartment does not restrict lung expansion.

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.

Sign in / Sign up

Export Citation Format

Share Document