scholarly journals Linearity of the vascular pressure-volume relationship of the canine intestine.

1980 ◽  
Vol 47 (4) ◽  
pp. 551-558 ◽  
Author(s):  
C F Rothe ◽  
T D Bennett ◽  
B L Johns
2017 ◽  
Vol 07 (02) ◽  
pp. e86-e92 ◽  
Author(s):  
Kathleen Antony ◽  
Diana Racusin ◽  
Michael Belfort ◽  
Gary Dildy

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.


1980 ◽  
Vol 239 (2) ◽  
pp. H189-H198 ◽  
Author(s):  
H. S. Goldberg

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.


1956 ◽  
Vol 40 (1) ◽  
pp. 91-105 ◽  
Author(s):  
C. Y. Kao

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.


1980 ◽  
Vol 53 (2) ◽  
pp. 173-179 ◽  
Author(s):  
Frederick H. Sklar ◽  
Jan T. Diehl ◽  
Chester W. Beyer ◽  
W. Kemp Clark

✓ 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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