Molecular Permeability of the Burned Area

The increased permeability of the walls of capillary blood vessels adjacent to a burned area is now well established. It was demonstrated by observing the coloring surrounding the burned area after injection of a dye which is adsorbed on serum albumin and so indicates the escape of this protein from the circulation into the tissues, Gibson(1), Cope, Graham, Moore & Ball(2). More recently measurements of capillary permeability have been made in dogs injected with dextran of Mw 40,000 by determining turbidimetrically the molecular weight distribution of the dextran present in serum and lymph from the burn, Arturson(3). Probably this increased permeability occurs in burns of man and contributes to the changes observed in the protein composition of the serum. A prominent clinical feature of some burns is loss of fluid from the burn surface itself. The protein composition of this exudate has occasionally been examined by zone electrophoresis which reveals the presence of the well known electrophoertic fractions. Two recent technical developments have enabled burn exudate to be recovered and analyzed in a way which yields information about the permeability of the burned area itself. The first of these developments is the polyurethane plastic foam burn dressing from which exudate may readily and almost quantitatively be recovered by centrifugal draining. The second development is molecular sieving by gel-filtration on columns of Sephadex which enables the distribution of molecular size in a small sample of dextran to be measured much more simply than has hitherto been possible. The Table shows clinical details of the burns and transfusions given. Dextran of mean molecular weight Mw 110,000 was used and contained a sufficient range of molecular size to challenge adequately the permeability at the molecular sizes of serum proteins.