Lung deformations at minimal volume.
Minimal volume (MV, gas plus tissue volume at zero transpulmonary pressure) was determined in excised dog lobes after inflation with air and with saline. MV was significantly greater in saline-filled lobes than air-filled lobes. Air inflation was performed with the lobe supported in two different ways, which were chosen to produce different deformations: 1) supported on the cephalic surface and 2) hung by strings attached to the cephalic surface. MV measured in hung lobes was significantly greater than MV measured in supported lobes. The problem of excised lobes deformed by gravity was analyzed in the two configurations using linear elasticity. The saline volume was assumed to be the stress-free state for the lobe, and the volume change was computed from the stress-free state due to the gravitational deformation. The analysis suggests that the difference between saline and air MV is due primarily to the gravitational deformation of air-filled lungs.
D000388:Air; D000818:Animals; D004285:Dogs; D006112:Gravitation; D066298:In Vitro Techniques; D008168:Lung / Q000502:physiology*; D008170:Lung Compliance; D008176:Lung Volume Measurements; D008433:Mathematics; D011312:Pressure; D012965:Sodium Chloride / Q000494:pharmacology
D012965:Sodium Chloride