Permeability of the alveolocapillary membrane during unilateral lung lavage. An experimental study

: Experimental unilateral continuous lung lavage in a nonregenerating system containing 3000 ml isotonic crystalloid was performed in 12 pigs to determine the permeability of the alveolocapillary membrane under these conditions. The maximum time of lavage was 270 min. The concentrations of ions in both serum and fluid were determined at defined intervals. Exponential functions adjusted to the electrolyte changes in the fluid suggest different types of kinetics: sodium and urea adapted rapidly to serum concentrations. The half-time of the exponential function was short, the permeability constant high. Calcium, phosphate, and creatinine increased significantly, the permeability constant being lower than for urea. Potassium showed a linear increase, possibly due to influx from intracellular compartments. Total protein and albumin increased only initially, levelling far below the serum values. The low permeability constants of protein and albumin indicate an almost total lack of permeation, the initial increase possibly being due to washout of the epithelial lining fluid compartment. There was only a minimal loss of lavage fluid into the organism.