title: Pleural and extrapleural interstitial liquid pressure measured by cannulas and micropipettes.
abstract: In 15 anesthetized apneic, oxygenated rabbits we simultaneously measured pleural liquid and interstitial extrapleural parietal pressures by using catheters and/or cannulas and micropipettes connected to a servonull system. With the animal in lateral posture, at an average recording height of 4.4 +/- 0.9 (SD) cm from the most dependent part of the cavity, the extrapleural catheter and the pleural cannula yielded -2.5 +/- 0.6 and -5.5 +/- 0.2 cmH2O; the corresponding values for micropipette readings in the two compartments were -2.4 +/- 0.6 and -5.4 +/- 0.4 cmH2O, respectively (not significantly different from those measured with catheters and cannulas). In the supine animal, interstitial extrapleural catheter pressure data obtained at recording heights ranging from 15 to 80% of pleural cavity lay on the identity line when plotted vs. the micropipette pressure values simultaneously gathered from the same tissues. We conclude that 1) micropipettes and catheters-cannulas yield similar results when recording from the same compartment and 2) the hydraulic pressure in the parietal extrapleural interstitium is less negative than that in the pleural space.
authors.affiliation: Istituto di Fisiologia Umana I, Università di Milano, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Miserocchi
authors.forename: S
authors.initials: S
authors.lastname: Kelly
authors.forename: D
authors.initials: D
authors.lastname: Negrini
mesh_terms: D000818:Animals; D002404:Catheterization; D005110:Extracellular Space / Q000502:physiology*; D006874:Hydrostatic Pressure; D010994:Pleura / Q000502:physiology*; D011817:Rabbits