Pulmonary Compliance | ScienceGate

Introduction: Lung dysfunction following cardiac surgery is currently viewed as the consequence of atelectasis and lung injury. While the mechanism of atelectasis has been largely detailed, the pathogenesis of lung injury after cardiopulmonary bypass is still unclear. Based upon clinical and experimental studies, we hypothesized that lungs could be injured through a mechanical phenomenon. Methods: We recorded pulmonary compliance at six key moments of a heart operation in 62 adult patients undergoing elective cardiac surgery. We focused on the period lasting from anesthetic induction to aorta unclamping. We calculated the variation of static and dynamic pulmonary compliance caused by thorax opening; ΔCstat1 and ΔCdyn1 and that caused by cardiopulmonary bypass, ΔCstat2 and ΔCdyn2. Blood gases were performed under standardized ventilation after anesthetic induction and after surgical closure. The PaO2/FiO2 ratio was calculated. ∆PaO2/FiO2 was the criterion for lung dysfunction. We compared ΔCstat1 and ΔCdyn1 with both ∆PaO2/FiO2 and, respectively, ΔCstat2 and ΔCdyn2. Results: Static and dynamic compliance increased with the opening of the thorax and decreased with the start of cardiopulmonary bypass. The PaO2/FiO2 ratio diminished after surgery. ΔCstat1 and ΔCdyn1 were negatively correlated with both ∆PaO2/FiO2 (r=-0.42; p<0.001 and r=-0.44; p<0.001) and, respectively, with ΔCstat2 and ΔCdyn2 (r=-0.59; p<0.001 and r=-0.53; p<0.001). Conclusions: Increased pulmonary compliance induced by the opening of the thorax is correlated with worsened intrapulmonary shunt after cardiopulmonary bypass. A mechanical phenomenon could be partly responsible for post-operative hypoxemia.

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Novel method to calculate pulmonary compliance images in rodents from computed tomography acquired at constant pressures

Physics in Medicine and Biology ◽

10.1088/0031-9155/51/5/003 ◽

2006 ◽

Vol 51 (5) ◽

pp. 1101-1112 ◽

Cited By ~ 25

Author(s):

Thomas Guerrero ◽

Richard Castillo ◽

Kevin Sanders ◽

Roger Price ◽

Ritsuko Komaki ◽

...

Keyword(s):

Computed Tomography ◽

Pulmonary Compliance ◽

Novel Method

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Experiment to Help Students Understand Pulmonary Compliance

AJP Advances in Physiology Education ◽

10.1152/advan.00007.2002 ◽

2002 ◽

Vol 26 (2) ◽

pp. 135-136 ◽

Cited By ~ 7

Author(s):

Stephen E. DiCarlo, ◽

Heidi L. Collins ◽

David W. Rodenbaugh

Keyword(s):

Pulmonary Compliance

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Factors Affecting Pulmonary Compliance and Airway Resistance

Anesthesiology Review ◽

10.1016/b978-0-443-06601-6.50008-6 ◽

2002 ◽

pp. 6-7

Author(s):

Michael L. Bishop

Keyword(s):

Airway Resistance ◽

Factors Affecting ◽

Pulmonary Compliance

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Effect of O2 breathing on pulmonary compliance

Journal of Applied Physiology ◽

10.1152/jappl.1962.17.2.233 ◽

1962 ◽

Vol 17 (2) ◽

pp. 233-238 ◽

Cited By ~ 10

Author(s):

Zora J. Griffo ◽

Albert Roos

Keyword(s):

Atmospheric Pressure ◽

Human Subjects ◽

Normal Subjects ◽

Pure Oxygen ◽

Pulmonary Atelectasis ◽

Air Breathing ◽

Oxygen Breathing ◽

Pulmonary Compliance ◽

Effect Of Oxygen

The effect of oxygen breathing on pulmonary compliance was studied in paralyzed, artificially ventilated dogs and in two normal subjects. 1) In the dogs and the human subjects the course of compliance during oxygen breathing for periods of 1frac12–2 hr following hyperinflation was compared with that during air breathing. 2) In dogs compliance after apnea on oxygen (following hyperinflation) for frac12–7 min was compared with that after apnea on air. Intrapulmonary pressure during apnea was atmospheric. 3) In the human subjects the course of compliance was followed during air breathing for 50–70 min, preceded by hyperinflation and immediately followed by oxygen breathing for 80–100 min. In none of these three sets of studies did oxygen breathing affect the course or magnitude of pulmonary compliance. It is concluded that breathing pure oxygen at atmospheric pressure for several hours does not enhance the development of pulmonary atelectasis in normal subjects. Submitted on July 3, 1961

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Surface tension and pulmonary compliance in premature rabbits

Journal of Applied Physiology ◽

10.1152/jappl.1989.66.5.2039 ◽

1989 ◽

Vol 66 (5) ◽

pp. 2039-2044 ◽

Cited By ~ 15

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.

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