In 14 spontaneously breathing anesthetized rabbits, we used cyanoacrylate to glue a hollow capsule, at end expiration or at end inspiration, to the peritoneal surface of the tendinous portion of the diaphragm. The capsule was connected to a pressure transducer and a pipette calibrated in microliters. We filled the system with fluid and measured flow into the diaphragmatic surface facing the capsule (Fcap, μl/cm2), from liquid displacement in the pipette at different hydraulic pressures in the system (Pcap). Pleural liquid pressure was simultaneously measured in the supraphrenic region (Psup). Fcap was positively correlated to transdiaphragmatic pressure gradient (Psup-Pcap) and breathing frequency but was unaffected by protein concentration of capsular fluid. For a breathing frequency of 30 cycles/min and Psup - Pcap = -2 cmH2O, Fcap was 0.54 μl·min-1·cm-2 for capsules applied at end expiration and 10-fold greater for capsules applied at end inspiration. Data indicate that the diaphragmatic tendinous portion in rabbits is a draining site for peritoneal fluid and that the conductance of the draining pathways (lymphatic stomata) is related to diaphragmatic tension. In the intact rabbit the average peritoneal fluid drainage through the tendinous portion of the diaphragm (~16 cm2) was estimated at 43 μl/min.
|Number of pages||7|
|Journal||Journal of Applied Physiology|
|Publication status||Published - 1989|
ASJC Scopus subject areas
- Orthopedics and Sports Medicine
- Physical Therapy, Sports Therapy and Rehabilitation