Interstitial Fluid Pressure

Abstract

Interstitial fluid pressures in the lung were estimated in 39 dogs from pressure measurements made in implanted perforated capsules. Special operative procedures were used to minimize operative trauma of the lungs and infection and inflammation in and around the implanted capsules. In 86X of the preparations, the x-ray findings indicated little remaining inflammation and edema around the capsules, though autopsy findings indicated that a few of these did still have some edema not detectable by x-rays. In 29 of 34 animals in which x-ray findings indicated no edema, the intracapsular pressure was negative. The average of the measurements in all 34 animals was -5.8 mm Hg (± 0.8 SEM), and in the 29 animals with negative pressure values the average was -7.3 mm Hg (±0.6 SEM). In eight capsules the pressures were below -10 mm Hg, ranging to -16 mm Hg. Because the tissues around some of the capsules undoubtedly still had varying degrees of inflammation and edema, despite the failure of roentgenograms to show these, it is suggested that the normal interstitial fluid pressure of pulmonary tissues in dogs is somewhat more negative than the capsule pressure measurements indicate, perhaps as low as -10 mm Hg.

Physiology of the Pulmonary Circulation

“…By using implanted perforated capsules M eyer el al. [43] found evidence for there being a negative hydrostatic pressure, about -10 mm Hg or below, in this compartment. Levine el al.…”

“…Both changes would tend to reduce or stop further outward flux of fluid. With the method of implanted, perforated capsules a marked rise in the negative interstitial pressure was recorded on outward filtration of fluid [43]. If the interstitial fluid has a high protein content, then reduction in its osmotic pressure on dilution at outward movements of a protein-poor filtrate could be equally important.…”

Unilateral pulmonary oedema associated with old poliomyelitis.

“…The pressure in this space is more negative than in most peripheral tissues and a mean value lower than -10 mmHg is widely accepted. It has been shown experimentally that this pressure falls with inflation (Meyer et al, 1968), while the blood flow in the extra-alveolar vessels increases. The capillaries in the alveolar walls are subjected to alveolar pressure, while the vessels in the extra-alveolar space are exposed to the negative interstitial pressure.…”

“…The pressure in this space is more negative than in most peripheral tissues and a mean value lower than -10 mmHg is widely accepted. It has been shown experimentally that this pressure falls with inflation (Meyer et al, 1968), while the blood 690 …”

Cystic Fibrosis Transmembrane Conductance Regulator Potentiation as a Therapeutic Strategy for Pulmonary Edema: A Proof-of-Concept Study in Pigs

“…This pressure difference can be transmitted to alveolar epithelia through a change in the interstitial hydrostatic pressure. The change of interstitial hydrostatic pressure can be as high as 15 cm H 2 O (from -11 to 3 cm H 2 O), depending on the species (40). To our knowledge, no methods existed to evaluate the effect of elevated basolateral hydrostatic pressure on alveolar epithelia cells in vitro .…”