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.

Surface tension and pulmonary compliance in premature rabbits

1989 ◽  
Vol 66 (5) ◽  
pp. 2039-2044 ◽  
Author(s):  
M. R. Mercurio ◽  
J. M. Fiascone ◽  
D. M. Lima ◽  
H. C. Jacobs
Keyword(s):  
Surface Tension ◽  
Surface Properties ◽  
Pulmonary Surfactant ◽  
Dynamic Compliance ◽  
Ringer Solution ◽  
Tween 20 ◽  
Adult Rabbit ◽  
Equilibrium Surface ◽  
Equilibrium Surface Tension ◽  
Pulmonary Compliance

In vitro surface properties of pulmonary surfactant thought to be essential to its ability to increase pulmonary compliance include minimum surface tension less than 10 dyn/cm and large surface tension variability and hysteresis. We tested four surface-active agents (Tween 20, a detergent; and FC-100, FC-430, and FC-431, industrial fluorocarbons), all lacking these properties, for their ability to increase pulmonary compliance in surfactant-deficient premature rabbits. Fetal rabbits were delivered by cesarean section at 27 days (full term = 31 days) and injected via tracheostomy with 50% lactated Ringer solution, adult rabbit surfactant, or one of the four experimental agents. Dynamic compliance was measured using 1 h of mechanical ventilation followed by alveolar lavage. Each experimental agent produced a dynamic compliance significantly higher than 50% lactated Ringer solution and statistically equal to or greater than natural surfactant. Equilibrium surface tension of the agents and minimum and equilibrium surface tension of the alveolar washes each correlated with compliance (P less than 0.05). This suggests that some surface properties of pulmonary surfactant believed to be essential are not, although surface tension does seem to play a role in pulmonary compliance.

Effects of fixatives on function of pulmonary surfactant

2002 ◽  
Vol 93 (3) ◽  
pp. 911-916 ◽  
Author(s):  
H. Bachofen ◽  
U. Gerber ◽  
S. Schürch
Keyword(s):  
Surface Tension ◽  
Pulmonary Surfactant ◽  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Film Stability ◽  
Minimum Surface ◽  
Natural Surfactant ◽  
Equilibrium Surface Tension ◽  
Minimum Surface Tension ◽  
Surface Active

The structure of pulmonary surfactant films remains ill defined. Although plausible film fragments have been imaged by electron microscopy, questions about the significance of the findings and even about the true fixability of surfactant films by the usual fixatives glutaraldehyde (GA), osmium tetroxide (OsO4), and uranyl acetate (UA) have not been settled. We exposed functioning natural surfactant films to fixatives within a captive bubble surfactometer and analyzed the effect of fixatives on surfactant function. The capacity of surfactant to reach near-zero minimum surface tension on film compression was barely impaired after exposure to GA or OsO4. Although neither GA nor OsO4 prevented the surfactant from forming a surface active film, GA increased the equilibrium surface tension to above 30 mN/m, and both GA and OsO4 decreased film stability as seen in the slowly rising minimum surface tension from 1 to ∼5 mN/m in 10 min. In contrast, the effect of UA seriously impaired surface activity in that both adsorption and minimum surface tension were substantially increased. In conclusion, the fixatives tested in this study are not suitable to fix, i.e., to solidify, surfactant films. Evidently, however, OsO4 and UA may serve as staining agents.

Abdominal distension alters regional pleural pressures and chest wall mechanics in pigs in vivo

1991 ◽  
Vol 70 (6) ◽  
pp. 2611-2618 ◽  
Author(s):  
T. Mutoh ◽  
W. J. Lamm ◽  
L. J. Embree ◽  
J. Hildebrandt ◽  
R. K. Albert
Keyword(s):  
Chest Wall ◽  
Respiratory System ◽  
Functional Residual Capacity ◽  
Total Lung Capacity ◽  
Abdominal Cavity ◽  
Abdominal Distension ◽  
Abdominal Pressure ◽  
Lung Capacity ◽  
Lung Expansion ◽  
Residual Capacity

Abdominal distension (AD) occurs in pregnancy and is also commonly seen in patients with ascites from various causes. Because the abdomen forms part of the "chest wall," the purpose of this study was to clarify the effects of AD on ventilatory mechanics. Airway pressure, four (vertical) regional pleural pressures, and abdominal pressure were measured in five anesthetized, paralyzed, and ventilated upright pigs. The effects of AD on the lung and chest wall were studied by inflating a liquid-filled balloon placed in the abdominal cavity. Respiratory system, chest wall, and lung pressure-volume (PV) relationships were measured on deflation from total lung capacity to residual volume, as well as in the tidal breathing range, before and 15 min after abdominal pressure was raised. Increasing abdominal pressure from 3 to 15 cmH2O decreased total lung capacity and functional residual capacity by approximately 40% and shifted the respiratory system and chest wall PV curves downward and to the right. Much smaller downward shifts in lung deflation curves were seen, with no change in the transdiaphragmatic PV relationship. All regional pleural pressures increased (became less negative) and, in the dependent region, approached 0 cmH2O at functional residual capacity. Tidal compliances of the respiratory system, chest wall, and lung were decreased 43, 42, and 48%, respectively. AD markedly alters respiratory system mechanics primarily by "stiffening" the diaphragm/abdomen part of the chest wall and secondarily by restricting lung expansion, thus shifting the lung PV curve as seen after chest strapping. The less negative pleural pressures in the dependent lung regions suggest that nonuniformities of ventilation could also be accentuated and gas exchange impaired by AD.

Reduction of Alveoli Surface Tension Using Pressure Oscillation

2012 ◽  
Author(s):  
A. M. Al-Jumaily ◽  
P. I. Reddy
Keyword(s):  
Surface Tension ◽  
Tidal Volume ◽  
Functional Residual Capacity ◽  
Pressure Oscillation ◽  
Effect Of Pressure ◽  
Interfacial Surface ◽  
Residual Capacity

This research investigates the effect of pressure oscillation (PO) on the alveoli surface tension. Experimental and modeling simulations are used to show that introducing superimposed oscillations on the tidal volume excursion between 0–70Hz in a surfactant bubble lowers interfacial surface tension below values observed using tidal volume excursion alone. Evidently this makes it easier for an infant with RDS to maintain the required level of functional residual capacity without collapse.

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)

Interaction between the canine diaphragm and intercostal muscles in lung expansion

2005 ◽  
Vol 98 (3) ◽  
pp. 795-803 ◽  
Author(s):  
André De Troyer
Keyword(s):  
Endotracheal Tube ◽  
Functional Residual Capacity ◽  
Phrenic Nerve ◽  
Intrathoracic Pressure ◽  
Abdominal Pressure ◽  
Intercostal Muscles ◽  
Individual Volume ◽  
Lung Expansion ◽  
Residual Capacity ◽  
The Individual

Changes in intrathoracic pressure produced by the various inspiratory intercostals are essentially additive, but the interaction between these muscles and the diaphragm remains uncertain. In the present study, this interaction was assessed by measuring the changes in airway opening (ΔPao) or transpulmonary pressure (ΔPtp) in vagotomized, phrenicotomized dogs during spontaneous inspiration (isolated intercostal contraction), during isolated rectangular or ramp stimulation of the peripheral ends of the transected C5 phrenic nerve roots (isolated diaphragm contraction), and during spontaneous inspiration with superimposed phrenic nerve stimulation (combined diaphragm-intercostal contraction). With the endotracheal tube occluded at functional residual capacity, ΔPao during combined diaphragm-intercostal contraction was nearly equal to the sum of the ΔPao produced by the two muscle groups contracting individually. However, when the endotracheal tube was kept open, ΔPtp during combined contraction was 123% of the sum of the individual ΔPtp ( P < 0.001). The increase in lung volume during combined contraction was also 109% of the sum of the individual volume increases ( P < 0.02). Abdominal pressure during combined contraction was invariably lower than during isolated diaphragm contraction. It is concluded, therefore, that the canine diaphragm and intercostal muscles act synergistically during lung expansion and that this synergism is primarily due to the fact that the intercostal muscles reduce shortening of the diaphragm. When the lung is maintained at functional residual capacity, however, the synergism is obscured because the greater stiffness of the rib cage during diaphragm contraction enhances the ΔPao produced by the isolated diaphragm and reduces the ΔPao produced by the intercostal muscles.

Disparity between tidal and static volumes of immature lungs treated with reconstituted surfactants

1996 ◽  
Vol 80 (1) ◽  
pp. 62-68 ◽  
Author(s):  
T. Kobayashi ◽  
W. Z. Li ◽  
K. Tashiro ◽  
R. Takahashi ◽  
Y. Waseda ◽  
...  
Keyword(s):  
Surface Tension ◽  
Pulmonary Surfactant ◽  
Static Pressure ◽  
Surfactant Adsorption ◽  
Minimum Surface ◽  
Natural Surfactant ◽  
Minimum Surface Tension ◽  
Volume Measurements ◽  
Porcine Lungs

We biologically assessed functions of several reconstituted surfactants with the same minimum surface tension (2-3 mN/m) as “complete” porcine pulmonary surfactant (natural surfactant) but with longer surface adsorption times. Administration of natural surfactant (adsorption time 0.29 s) into the lungs of surfactant-deficient immature rabbits brought a tidal volume of 16.1 +/- 4.4 (SD) ml/kg during mechanical ventilation with 40 breaths/min and 20 cmH2O insufflation pressure. In static pressure-volume recordings, these animals showed a lung volume of 62.4 +/- 9.7 ml/kg at 30 cmH2O airway pressure and maintained 55% of this volume when the pressure decreased to 5 cmH2O. With two reconstituted surfactants consisting of synthetic lipids or isolated lipids from porcine lungs plus surfactant-associated hydrophobic proteins (adsorption times 0.57 and 0.78 s, respectively), tidal volumes were < 38% of that with natural surfactant (P < 0.05), but static pressure-volume recordings were not different. Care is therefore needed in estimating the in vivo function of surfactant preparations from minimum surface tension or static pressure-volume measurements.

Lung volume, compliance, and arterial oxygen tensions during controlled ventilation

1964 ◽  
Vol 19 (4) ◽  
pp. 725-733 ◽  
Author(s):  
Myron B. Laver ◽  
John Morgan ◽  
Henrik H. Bendixen ◽  
Edward P. Radford
Keyword(s):  
Functional Residual Capacity ◽  
Dynamic Compliance ◽  
Constant Volume ◽  
Pure Oxygen ◽  
Whole Body ◽  
Arterial Oxygen ◽  
Deep Breath ◽  
Volume Ventilation ◽  
Residual Capacity ◽  
Total Compliance

The relationship between total dynamic compliance (lung plus chest wall), functional residual capacity, and alveolar-arterial oxygen gradients (A-a DO2) was studied in paralyzed dogs during constant-volume ventilation with pure oxygen. Rapid changes in functional residual capacity (FRC), produced by forced deflation of the lungs, were associated with a rapid fall in total compliance and rise in A-a DO2. Subsequent hyperinflations (deep breaths) restored compliance to control levels more readily than A-a DO2. Changes in the FRC, measured with a whole-body plethysmograph, were related directly to total compliance and inversely to A-a DO2. Collapse of the terminal regions of the lungs produced by forced deflations was associated with a decrease in total compliance of 36%, and a decrease in FRC of 26% with a simultenaous rise in A-a DO2 to a mean of 547 mm Hg. It is concluded that intermittent deep breaths administered during constant-volume ventilation will not necessarily restore control levels of compliance and A-a DO2 equally well. This difference is probably dependent on altered alveolar surface characteristics or mechanics, or both, secondary to the collapse process, which prevent restoration of structural integrity by a deep breath. total dynamic compliance; functional residual capacity; alveolar-arterial oxygen tension difference; atelectasis; deep breath Submitted on October 31, 1963

Increased surface tension decreases pulmonary capillary volume and compliance

2002 ◽  
Vol 93 (3) ◽  
pp. 1023-1029 ◽  
Author(s):  
George P. Topulos ◽  
Richard E. Brown ◽  
James P. Butler
Keyword(s):  
Surface Tension ◽  
Functional Residual Capacity ◽  
Total Lung Capacity ◽  
Lung Mechanics ◽  
Lung Capacity ◽  
Pulmonary Capillary ◽  
Before And After ◽  
Residual Capacity ◽  
Surface Tension Change ◽  
Ventilation And Perfusion

Increased surface tension is an important component of several respiratory diseases, but its effects on pulmonary capillary mechanics are incompletely understood. We measured capillary volume and specific compliance before and after increasing surface tension with nebulized siloxane in excised dog lungs. The change in surface tension was sufficient to increase lung recoil 5 cmH2O at 50% total lung capacity. Increased surface tension decreased both capillary volume and specific compliance. The changes in capillary volume and compliance were greatest at the lung volumes at which the surface tension change was greatest. Near functional residual capacity, capillary volume postsiloxane was ∼30% of control. Presiloxane capillary specific compliance was ∼7%/cmH2O near functional residual capacity and ∼2.5%/cmH2O near total lung capacity. Postsiloxane capillary-specific compliance was 3%/cmH2O, and was independent of lung volume. We conclude that in addition to their well-known effects on lung mechanics, changes in surface tension also have important effects on capillary mechanics. We speculate that these changes may in turn affect ventilation and perfusion, worsen gas exchange, and alter leukocyte sequestration.

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