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RESULTS reduced form act as good buffering agents of the body.
Hemostasis, inflammation, proliferation and remodeling
In total, 215 patients were screened, 140 patients were are the four overlapping phases of wound healing. Altered
randomized, of whom 64 were assigned to the LAD or impaired healing of chronic wounds is the result of an
group and 76 to the conventional group [Figure 1]. interruption in the various processes of these four phases
Of the 56 participants, 22 in the LAD group and 34 in of wound healing. Changes in the pH of the wound surface
the conventional dressing group were lost to follow‑up may be induced by application of topical preparations that
or withdrawn from the study. The results of wound influence the cellular events in wound healing. Subjective
surface pH in chronic ulcer patients of the LAD group evaluation of the wound bed is performed by clinicians
as compared to that of the conventional dressing group when making clinical decisions regarding management.
shown in Table 2. A simple system for monitoring wound pH may provide
an objective method for clinicians when deciding upon the
DISCUSSION course of treatment. [10]
The pH environment of chronic wounds has been recorded
The acidity and alkalinity are measured by pH value, that within the range of 7.15‑8.9. [11‑13] Both acute and chronic
is, pH is a measurement of the concentration of H in wounds with an elevated alkaline pH have demonstrated
+
the body. It ranges from 1 to 14, with pure water at lower rates of healing than wounds in which the pH is
a pH of 7 to be considered neutral. Acidic solution has a closer to neutral. [5,10,14] Chronic wounds exhibit excessive
pH of less than 7 and basic or alkaline solutions have a breakdown of the extracellular matrix, and this occurs
pH more than 7. Body pH can be tested using litmus paper more readily when the wound has an alkaline pH [14,15]
immersed in saliva or urine. Even a minor variation in the which may contribute to nonhealing ulcers. A study by
+
concentration of H can alter the rate of many biochemical Greener et al. showed that every protease shows peak
[15]
processes. Body pH can change secondary to diet, enzyme activity at certain pH levels, where the protein
consumption of chemicals, exercise and various diseases is broken down more rapidly than at other pH values.
altering the metabolism of body. Topical applications For example, cathepsins G has peak activity at pH 7.0,
may change the body surface pH. Wound healing is elastase at 8.0, matrix metalloproteinases 2 (MMP‑2) at
regulated by complex chemical processes mediated by 8.0, and neutrophil elastase at 8.3. The shift of the pH in
various enzymes and hormones. Hence, various intrinsic a wound environment from alkaline to acidic favors the
and extrinsic factors may influence the pH of the wound production of healthy granulation tissue by decreasing
environment, leading to alterations in the healing process. the growth of bacteria and MMPs. The alteration of
[15]
Therefore, events in wound healing including vasodilation, surface pH of wounds by the use of topical preparations
inflammation, release of oxygen into the wound bed, has been used to promote healing. [16,17] In the present
protease activity and the release and effects of bacterial study, the wound surface pH of LAD vs. conventional
toxins may be significantly influenced by the pH of the dressing on day 0 was (mean ± SD) 8.33 ± 0.35 vs.
wound. The pH of body fluids and tissues is stabilized by 8.31 ± 0.38. On day 10, the mean wound surface
various protein buffering systems. Hydrogen ions bind to pH (± SD) in the LAD vs. conventional dressing group
protein molecules or bound hydrogen ions are released, was 7.5 ± 0.43 vs. 7.9 ± 0.47. The decrease in the mean
changing their concentration in the body’s tissues and wound surface pH (± SD) after 10 days of treatment in
fluids. Intracellular buffers such as hemoglobin in its the LAD group was 0.83 ± 0.52 while in the conventional
dressing group, it was 0.41 ± 0.26 (P = 0.048).
Table 1: Patient demographics and wound characterization LAD is a newer method of dressing which combines the
at baseline principles of both negative pressure and moist wound
LAD group Conventional group healing. It utilizes a definite intermittent negative
Number of patients 42 42 pressure regimen of 30 min of negative pressure followed
Age, years 38.3 ± 10.56, 35.3 ± 14.0, by a rest period of 3.5 h. During the period without
(mean±SD, range) 12-60 years 17-65 years negative pressure, the LAD acts as a moist wound
Mean wound size (cm ) 28 (range: 19-40) 26 (range: 18-39) dressing. The wound bed preparation period has been
2
Female (%) 52 42.8 shown to be reduced in LAD as compared to conventional
Male (%) 48 57.1 dressings. Also, the percentage of graft take under LAD
[8]
[8]
SD: Standard deviation, LAD: Limited access dressing has been shown to be higher. LADs have been shown to
Table 2: Results of wound surface pH in the LAD (n = 42) and conventional dressing group (n = 42)
Parameters Mean ± SD P
LAD group (n = 42) Conventional dressing group (n = 42)
Day 0 Day 10 Day (0‑10) Day 0 Day 10 Day (0‑10)
Wound surface pH 8.33 ± 0.35 7.5 ± 0.43 0.83 ± 0.52 8.31 ± 0.38 7.9 ± 0.47 0.41 ± 0.26 0.048
SD: Standard deviation, LAD: Limited access dressing

Plast Aesthet Res || Vol 2 || Issue 5 || Sep 15, 2015 259