Lung capillary filtration coefficient was measured to quantify lung vascular permeability, as described previously. 16 Venous outflow pressure was elevated using a computer-controlled two-way electronic pinch valve (P/N 98301-22; Cole-Parmer Instrument Co., Vernon Hills, IL) that channeled venous fluid into silicon tubing (1/16-inch i.d.). The weight change resulting from the venous pressure increase of 6 cm of water was recorded for 5 minutes. The weight recording has two exponential components that reflect the rapid expansion of vascular volume and the slower phase of transvascular fluid filtration. The amount of fluid filtered in 5 minutes was determined via logarithmic extrapolation of the slower component to time 0. The lung capillary filtration coefficient, a measure of lung vascular liquid permeability, was computed as milliliters per minute per centimeter of water per gram dry weight by normalizing the estimate of filtered fluid by time, venous pressure change, and lung dry weight.