We investigated a simple method that can be used at the bedside for documenting the net accumulation of albumin in the lung. The technique employs measurement with a computer-linked gamma camera of the activity ratio in an area of the right lung compared with the same-sized area in the heart at 20 minutes and three hours following intravenous injection of technetium Tc 99m albumin. We applied this measurement to three groups of patients: a control group and patients with roentgenographic evidence of edema classified according to clinically available criteria as either hydrostatic edema or permeability edema to see if we could document differences among these groups. In control patients this ratio did not increase by more than seven units between the 20-minute and three-hour measurements. Of 18 patients classified by other routine clinical means as having hydrostatic pulmonary edema, 89% showed no increase in lung albumin accumulation. In 29 patients with permeability edema associated with the so-called adult respiratory distress syndrome, 31% showed evidence of net pulmonary albumin accumulation. These findings suggest that some patients otherwise classified as having hydrostatic edema have concomitant permeability changes in the microvasculature and that permeability edema represents a spectrum of endothelial damage.
Fred S. Mishkin, Albert Niden, Ashok Kumar, Alvin Thomas, Isaac C. Reese, Panukorn Vasinrapee. Albumin Lung/Heart Ratio ChangeA Simple Clinical Means of Documenting Increased Pulmonary Endothelial Permeability to Protein. JAMA. 1987;257(7):953–956. doi:10.1001/jama.1987.03390070073026