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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          or  withdrawn from  the  study.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
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