Moisture and healing: beyond the jargon.

Moist wound healing is one of the most frequently used, but least understood terms in wound care. Although no reliable operational definitions exist of too little or too much wound surface moisture, a low dressing water vapor transmission rate (WVTR) has proven to be a reliable measure of a dressing's capacity to retain moisture and provide an environment that supports healing. Dressing WVTR is a powerful linear predictor of both full- and partial-thickness healing of standardized acute wounds in vivo (alpha < 0.0001). Moreover, differences in the ability to produce an optimal moist wound environment within a dressing category, such as hydrocolloid dressings, are strongly correlated with dressing WVTR, suggesting that dressings in the same product categories may be associated with significantly different environments for healing. Even though the correlation between dressing WVTR and healing rates is more difficult to ascertain, clinical healing percentages during similar time-frames and healing times of similar wounds also follow patterns predicted by dressing moisture retention. These results suggest that, when other variables are held constant, use of more moisture-retentive dressings generally achieves environments supportive of earlier healing outcomes when compared to less moisture-retentive dressings. Maceration, an unwelcome occurrence with moisture-retentive dressing use on highly exuding wounds, is not consistently associated with increased adverse events. Evidence further suggests that greater dressing moisture retention is associated with fewer clinical infections, greater patient comfort, and reduced scarring.