A qualitative and quantitative analysis of protein loss in human burn wounds

It is well known that in patients suffering from major burn injuries of more than 15% of total body surface area (TBSA), capillary leak and loss of proteins including immunoglobulins (Ig) lead to cardiovascular failure and significantly elevated risk of infections. However, knowledge of the resulting protein profiles is limited. In order to elucidate quantitative and qualitative protein loss in human burn wounds we compared wound fluid (WF) protein content with serum protein levels.

Eleven patients suffering from second degree burns of 18-68% TBSA were enrolled in the study. Immediately after admission burn wounds were enclosed in cutaneous vinyl wound chambers covering a 2.25 cm(2) wound surface area. WF and serum samples were harvested every 8 h with a follow up of 48 h and analyzed for total protein content, albumin and the immunoglobulins A, E, G and M.

Protein levels in serum were significantly lower as compared to physiological levels while WF protein levels were elevated and remained high. Total protein (TP) and albumin (AL) accumulated in high concentrations on the wound surface (average accumulation on 10% burnt TBSA within 8 h: TP=16.59+/-8.86 g; AL=12.39+/-5.87 g). The albumin fraction in WF showed increasing values (24 h: 69%; 32 h: 86%) although the serum albumin fraction remained nearly unchanged (55%). Peak values were initially found for all immunoglobulins both in serum and WF. IgA, E and M reached a steady state 32 h post-trauma, whereas IgG continuously decreased until 40 h. IgG values in serum were significantly below physiological levels at all time points.

This study qualifies and quantifies a significant protein loss in second degree burn wounds. Protein concentrations in wound fluid correlate highly with serum concentrations until 48 h post-burn. A patient's entire amount of serum proteins accumulates in wound fluid in a 20% TBSA burn within approximately 24h. In contrast to capillary leak theory proteins and immunoglobulins extravasate to wound fluid even after 48 h post-trauma.