Changes in chest wall structure and elasticity in elastase-induced emphysema

1986 ◽  
Vol 61 (5) ◽  
pp. 1821-1829 ◽  
Author(s):  
A. J. Thomas ◽  
G. S. Supinski ◽  
S. G. Kelsen
Keyword(s):  
Chest Wall ◽  
Spinal Column ◽  
Wall Structure ◽  
Rib Cage ◽  
Thoracic Spinal ◽  
Volume Curve ◽  
Volume Relationship ◽  
Pressure Volume Relationship ◽  
Relationship Of ◽  
Anterior Posterior

The present study examined the effects of elastase-induced emphysema on the structure and elasticity of the chest wall. Specifically, we examined the passive pressure-volume relationship of the intact chest wall in anesthetized animals and the stress-strain relationship of the isolated rib cage devoid of respiratory musculature. The structure of the isolated rib cage was assessed by measuring its circumferential, anterior-posterior, and transverse dimensions, the angles of articulation of the ribs at the costovertebral and sternochondral joints, and the length of the sternum and individual ribs. Studies were performed in 10 Syrian Golden hamsters, 26–27 wk after intratracheal injection of elastase, and 9 saline-injected hamsters that served as controls. Mean functional residual capacity of emphysematous animals was 239% of the value obtained in control animals. In emphysematous animals, the pressure-volume curve of the chest wall was shifted parallel and to the left of the curve obtained in controls. That is, at any given esophageal pressure, lung volume was significantly greater in emphysematous animals compared with controls, but the slope of the pressure-volume relationship was similar in the two groups. In the relaxed position, the circumference, anterior-posterior, transverse, and rostral-caudal dimensions of the thorax were significantly greater in emphysematous than control animals. Although the length of the thoracic spinal column was the same in both groups, the length of the ribs and sternum were greater in emphysematous animals and the angles of articulation of the ribs with the vertebrae and sternum were altered.(ABSTRACT TRUNCATED AT 250 WORDS)

Chest wall mechanics during artificial ventilation

1975 ◽  
Vol 38 (4) ◽  
pp. 576-580 ◽  
Author(s):  
G. Grimby ◽  
G. Hedenstierna ◽  
B. Lofstrom
Keyword(s):  
Tidal Volume ◽  
Chest Wall ◽  
Gas Flow ◽  
Artificial Ventilation ◽  
Conscious State ◽  
Rib Cage ◽  
Chest Wall Mechanics ◽  
Pressure Volume Relationship ◽  
Relationship Of ◽  
Gas Volume

Chest wall mechanics were studied in six healthy volunteers before and during anesthesia prior to surgery. The intratracheal, esophageal, and intragastric pressures were measured concurrently. Gas flow was measured by pneumotachography and gas volume was obtained from it by electrical integration. Rib cage and abdomen movements were registered with magnetometers, these being calibrated by “isovolume” maneuvers. During spontaneous breathing in the conscious state, rib cage volume displacement corresponded to 40% of the tidal volume. During anesthesia and artificial ventilation, this rose to 72% of the tidal volume. The relative contributions of rib cage and abdomen displacements were not influenced by a change in tidal volume. Compliance was higher with a larger tidal volume, a finding which could be due to a curved pressure-volume relationship of the overall chest wall.

scholarly journals Under Pressure: Intraluminal Filling Pressures of Postpartum Hemorrhage Tamponade Balloons

2017 ◽  
Vol 07 (02) ◽  
pp. e86-e92 ◽  
Author(s):  
Kathleen Antony ◽  
Diana Racusin ◽  
Michael Belfort ◽  
Gary Dildy
Keyword(s):  
Postpartum Hemorrhage ◽  
Ex Vivo ◽  
Volume Ratio ◽  
Intraluminal Pressure ◽  
Acute Hemorrhage ◽  
Volume Relationship ◽  
Pressure Volume Relationship ◽  
Relationship Of ◽  
Condom Catheter ◽  
Filling Capacity

Objective Uterine tamponade by fluid-filled balloons is now an accepted method of controlling postpartum hemorrhage. Available tamponade balloons vary in design and material, which affects the filling attributes and volume at which they rupture. We aimed to characterize the filling capacity and pressure-volume relationship of various tamponade balloons. Study Design Balloons were filled with water ex vivo. Intraluminal pressure was measured incrementally (every 10 mL for the Foley balloons and every 50 mL for all other balloons). Balloons were filled until they ruptured or until 5,000 mL was reached. Results The Foley balloons had higher intraluminal pressures than the larger-volume balloons. The intraluminal pressure of the Sengstaken-Blakemore tube (gastric balloon) was initially high, but it decreased until shortly before rupture occurred. The Bakri intraluminal pressure steadily increased until rupture occurred at 2,850 mL. The condom catheter, BT-Cath, and ebb all had low intraluminal pressures. Both the BT-Cath and the ebb remained unruptured at 5,000 mL. Conclusion In the setting of acute hemorrhage, expeditious management is critical. Balloons that have a low intraluminal pressure-volume ratio may fill more rapidly, more easily, and to greater volumes. We found that the BT-Cath, the ebb, and the condom catheter all had low intraluminal pressures throughout filling.

Toad bladder compliance and water permeability in response to stretch

1982 ◽  
Vol 242 (1) ◽  
pp. F8-F16
Author(s):  
P. Eggena
Keyword(s):  
Bladder Wall ◽  
Apical Cell ◽  
Bladder Capacity ◽  
Apical Plasma Membrane ◽  
Wall Tension ◽  
Optimal Capacity ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Pressure Volume Relationship ◽  
Relationship Of

The pressure/volume relationship of toad urinary bladders was measured from 0 to 50 cmH2O. Optimal bladder capacity was derived by extrapolation of the pressure/volume curve to a pressure of 0 cmH2O. The compliance of the bladder wall was calculated from the slope of the pressure/volume curve at intraluminal pressures above 10 cmH2O. Neither vasopressin nor atropine had any effect on bladder wall compliance. Bladders filled with one-fifth strength Ringer fluid and suspended in full-strength Ringer lost weight at 0.02 (at half-optimal capacity), 0.08 (at optimal capacity), and 0.26 mg.min-1.cm-2 (at supra-optimal capacity, 25 cmH2O) in the absence of vasopressin. With 20 mU/ml vasopressin, bladders lost weight at 1.08 (at half-optimal capacity), 1.55 (at optimal capacity), and 1.74 mg.min-1.cm-2 (at supra-optimal capacity, 25 cmH2O). When bladder wall tension was raised from 2,102 to 28,383 dyn/cm, the permeability to [14C]mannitol increased from 8 X 10(-7) to 39 X 10(-7) cm/s. Electron microscopy of bladders fixed at a wall tension of 17,572 dyn/cm showed flattening of the microvilli, rupture of the apical cell membranes of some granular and mitochondria-rich epithelial cells, but no obvious alteration in the tight junctions. This study suggests that stretching the apical plasma membrane to the point at which it ruptures in some cells does not alter the capacity of vasopressin to induce its characteristic increase in permeability to water of this membrane.

Pulmonary interstitial compliance and microvascular filtration coefficient

1980 ◽  
Vol 239 (2) ◽  
pp. H189-H198 ◽  
Author(s):  
H. S. Goldberg
Keyword(s):  
Dynamic Properties ◽  
Transpulmonary Pressure ◽  
Filtration Coefficient ◽  
Alveolar Pressure ◽  
Fluid Movement ◽  
Volume Relationship ◽  
Pressure Volume Relationship ◽  
Relationship Of ◽  
The Relationship

Static and dynamic properties governing the fluid movement into the pulmonary interstitium were examined in isolated canine lobes. The system was driven by altering intravascular presure (Piv) when the lobe was isogravimetric (change in weight (W) = 0) and allowing the lobe to become isogravimetric again. By making use of an analogy to charging a capacitor across a resistor, calculation of the filtration coefficient for transvascular fluid movement (KF) and determination of the pressure-volume relationship of the pulmonary interstitial space (Pis-Vis), with a minimum of untested assumptions, was possible. KF was found to be the same for fluid moving out of or into the intravascular space, and when the relationship between Piv and alveolar pressure (PAlv) was constant, KF was independent of transpulmonary pressure (PL). When PAlv exceeded Piv, changes in Piv did not influence KF, suggesting no significant change in either surface area available for fluid transudation or vascular permeability. The Pis-Vis curve for increasing values of Vis and Pis is best described by an exponential relationhip and is independent of PL. However, the Pis-Vis curve with decreasing values of Vis and Pis is dependent on PL.

scholarly journals PRESSURE-VOLUME RELATIONSHIP OF THE FUNDULUS EGG IN SEA WATER AND IN SUCROSE

1956 ◽  
Vol 40 (1) ◽  
pp. 91-105 ◽  
Author(s):  
C. Y. Kao
Keyword(s):  
Plasma Membrane ◽  
Hydrostatic Pressure ◽  
Sea Water ◽  
Sucrose Solution ◽  
Limiting Factor ◽  
Egg Volume ◽  
Rectangular Hyperbola ◽  
Volume Relationship ◽  
Pressure Volume Relationship ◽  
Relationship Of

Upon activation, an internal hydrostatic pressure develops within the Fundulus egg, and compresses the egg proper to a reduced volume. When the perivitelline pressure is abolished by a highly hypertonic sucrose solution, the egg volume increases. As sucrose penetrates the chorion, the volume again decreases. The relation between P and V in these conditions is inverse, and approximates a rectangular hyperbola. The limiting factor causing most of the deviation is shown to be the incompressible fraction. It is concluded that the volume of the egg proper is controlled by the perivitelline pressure, and that the effect of hypertonic sucrose solution is exerted by lowering the pressure and thereby increasing membrane permeability non-specifically. It is also shown that some permanent alterations occur within the plasma membrane during activation that reduce the permeance, and thereby, increase the incompressible fraction.

Brain elasticity changes with ventriculomegaly

1980 ◽  
Vol 53 (2) ◽  
pp. 173-179 ◽  
Author(s):  
Frederick H. Sklar ◽  
Jan T. Diehl ◽  
Chester W. Beyer ◽  
W. Kemp Clark
Keyword(s):  
Absorptive Capacity ◽  
Pulse Amplitude ◽  
Variable Rate ◽  
Ventricular Size ◽  
Content Type ◽  
Natural Logarithm ◽  
Volume Relationship ◽  
Pressure Volume Relationship ◽  
Relationship Of ◽  
Fine Print

✓ The pressure-volume relationship of brain elasticity was determined in 32 patients during servo-controlled variable-rate lumbar infusions to measure net cerebrospinal fluid (CSF) absorptive capacity. Several indices were used to estimate ventricular size from computerized tomography scans. The results show a linear relationship between ventricular size and the elasticity slope which relates the natural logarithm of pressure to volume. It follows that a hydrocephalic patient should show a greater intracranial pulse amplitude at a given pressure than does a patient with normal-sized ventricles. Although these elasticity changes may simply be the result of the ventriculomegaly, it seems possible that the pressure-volume elasticity relationship may be of etiological importance in disorders of the CSF system.

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