Do nutritional markers in wound fluid reflect pressure ulcer status?

Evaluation of wound fluid characteristics for pressure ulcer (PU) assessment in clinical settings remains subjective, requiring considerable expertise. This cross-sectional study focused on nutritional markers in wound fluid as possible objective tools and investigated whether they reflect the PU status according to the healing phase, infection, and granulation, especially after adjusting for serum values. Twenty-eight patients with 32 full-thickness PUs were studied. The concentration of albumin, total protein, glucose, and zinc in wound fluid were measured. For PU status, the healing phases and infection were evaluated by clinical signs, and the degree of granulation tissue formation was determined as the hydroxyproline concentration. The wound fluid/serum ratio for albumin was significantly lower during the inflammatory phase than during the proliferative phase (p=0.020). Infected wound fluid contained less glucose (0.3-1.0 mmol/L) than noninfected ones did (5.0-7.6 mmol/L) in an intraindividual comparison of three cases. The wound fluid/serum ratio for glucose was negatively correlated with hydroxyproline level in the proliferative phase (=-0.73, p=0.007), while zinc level in wound fluid showed a positive correlation (=0.61, p=0.028). Our results suggest that these traditional nutritional markers in wound fluid, especially wound fluid/serum ratio may be useful to evaluate local PU status.