Progression of Wound pH During the Course of Healing in Burns

Abstract

The aim of this study was to measure the pH on the wound surface of 30 burn patients and test the hypothesis that wound surface pH is correlated to healing time and burn depth. Inclusion criteria were any adult outpatient with burn injury. Patient age was 17 to 75 years (mean, 44), burn depth ranged from superficial to full thickness with a TBSA of 0.4 to 4%. Cause of burn included scalds, flame burn, and contact burns. On admission, and at each dressing change, the pH on the wound surface was measured. The pH in both healing and nonhealing wounds was found to decrease with each dressing change. At the second dressing change, wounds that went on to heal were found to have a significantly lower pH of 7.32 in comparison with pH 7.73 in wounds that failed to heal and therefore required subsequent grafting (P = .004). Wound pH was also correlated to depth at the second dressing change (superficial = pH 6.05, full thickness = pH 8.0). The correlation between pH and wound outcome could be used as an additional diagnostic tool to predict poor healing in wounds. Early identification of a nonhealing wound may allow a more aggressive treatment regimen, including skin grafting, to bring about rapid wound healing.

Staphylococcus aureus Induces Hypoxia and Cellular Damage in Porcine Dermal Explants

“…Acidic pH favors wound healing by enhancing fibroblast replication, early angiogenesis, and release of oxygen that is bound to hemoglobin (Bohr effect). This is in contrast with chronic wounds, where pH remains alkaline most of the time except during the epithelialization stage (11,12,20). S. aureus lives in acidic pH on skin surface (58,59), but our model indicates that once established in wounds, S. aureus biofilms increase pH, and this is likely to be an impediment to wound healing.…”

“…Formation of biofilms in wounds is a major cause of nonhealing wounds (5-7) and treatment failure (8). Oxygen and pH are two critical factors in wound healing (9)(10)(11)(12), but at present we have limited knowledge about how the presence of S. aureus biofilms affects oxygen and pH levels in wounds.…”

Pseudomonas Aeruginosa Elastase Disrupts the Cortisol-Binding Activity of Corticosteroid-Binding Globulin

“…In cases of infections accompanied by fever, any increase in proteolytic activity would act in concert with a decreased steroidbinding activity to enhance free cortisol levels. In addition, the LasB-induced cortisol release from CBG may vary according to the pH of an infected area, which will likely be different, for example between infected burn wounds (33) and airways (34).…”

Transitional changes in the CRP structure lead to the exposure of proinflammatory binding sites

“…We have predicted the p K a of the acidic residues on the intersubunit interface to be 8.4, 3.9, 4.6, 3.7, 6.1 and 4.0 for Asp155, Asp169, Glu42, Glu101, Glu108 and Glu197, respectively. The acidic pH observed at sites of inflammation and tissue injury ( in vitro and in vivo , pH 3.6–5.7)414243444546 will weaken the electrostatic intersubunit interactions (that is, salt bridges and hydrogen bonds) by protonating the acidic aspartic and glutamic acid side chains and the increased curvature of the surface will also assist to break the intersubunit cohesive forces (electrostatic and nonpolar interactions). The fluid motion of the microvesicle lipid bilayer provides a mechanical shear force and, coupled with the weakening of the pCRP intersubunit interactions, within 30 min on the surface pCRP starts to dissociate to pCRP* (ref.…”