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PLWS delivers pulsed, pressurized irrigation at controlled pounds per square inch (psi) along with simultaneous removal or suction of contaminated irrigation fluid, thereby combining the benefits of both positive and negative pressure in one modality. Research supports that the combination of these pressure forces facilitates wound cleansing, debridement of slough, loosening of nonviable tissue, reduction of surface bacteria, increased local perfusion, and stimulation of granulation tissue.1,2,10
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Positive pressure hydrotherapy for the management of open wounds can assist in general wound cleansing, debridement, and tissue stimulation (see TABLE 17-2). Whirlpool (WP) therapy, once considered the primary method of hydrotherapy,11 utilizes a turbine to generate positive pressure irrigation (FIGURE 17-3).1,3 However, with WP therapy, the psi created by the turbine at the wound surface has not been documented.11 Research supports that positive pressure hydrotherapy delivered at too low a psi can be ineffectual for wound cleansing and debridement; too high, and wound tissues are damaged and surface bacteria may be pushed deeper into the wound bed.12,13,14 For safe and effective delivery, the Agency for Health Care Policy and Research, the National Pressure Ulcer Advisory Panel, and the European Pressure Ulcer Advisory Panel recommend irrigation pressures for wound management stay between 4 and 15 psi.12,15 PLWS units are designed so that providers select known psi settings within the safe 4 to 15 psi range (FIGURE 17-4).
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Benefits associated with the negative-pressure component of PLWS are tissue stimulation, locally increased perfusion, reduction of surface bacteria,1 and removal of irrigation fluid (see TABLE 17-3). Research indicates that the suction force generated with the application of negative pressure stimulates granulation tissue proliferation and epithelialization through the process of cellular deformation and strain.2,10,16,17 Negative pressure also increases tissue perfusion by causing arterioles to dilate and thereby increasing local blood flow.2 Increased perfusion supports granulation tissue formation and enhances the body’s ability to destroy and digest bacteria in the wound.18 PLWS also assists with reducing bioburden1,19 through the following mechanical means:
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Debridement: the physical removal of loosened nonviable tissue and bacteria from the wound environment; removal of nonviable tissue also decreases food availability for remaining bacteria
Irrigation: removes microorganisms on the wound surface and in exudate as the irrigation fluid is evacuated
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Bioburden may also be decreased by adding topical antibacterial medications to irrigation solutions.2,16 This can be especially beneficial in treating severely immunocompromised patients or patients with heavily contaminated, traumatic injuries with or without exposed bone.4 However, PLWS reduces surface bacteria primarily through mechanical means, and there is no promotion of bacterial resistance (an increasing concern as drug resistance increases) when normal saline alone is used as the irrigation fluid.20 Additionally, when using antibiotic irrigation solutions (eg, bacitracin), the potential for allergic reactions to those medications must be considered21 whereas normal saline has little to no allergic potential. The selection of antibacterial irrigation is based on systemic as well as local wound presentation.
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CLINICAL CONSIDERATION
Using normal saline is usually sufficient for wound cleansing and debridement22; careful consideration is advised before adding agents to normal saline irrigation fluid. While antibiotic and toxic solutions temporarily decrease wound bioburden, they may damage tissues and kill healthy wound cells, allowing bacteria levels to rebound22 and thereby cause overall delay in wound healing.
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CASE STUDY INTRODUCTION
Ms PL is a 34-year-old female who has had gastric bypass surgery for morbid obesity, followed by hernia repair with mesh reinforcement. She has a history of diabetes Type 2, which resolved after the bypass surgery. The hernia repair incision, located in the right lower abdomen, became necrotic, dehisced, and ultimately required surgical incision and drainage (I&D) to remove the infected tissue. The patient has been referred for wound care in preparation for surgical closure (FIGURE 17-5). The wound measures 18.5 cm × 12.7 cm × 3.8 cm deep, and connects to a smaller opening that is 3.6 cm × 1.7 cm.
DISCUSSION QUESTION: What subjective and objective information do you need about this patient in order to develop a plan of care?
The systems review for this patient was negative for any cardiac, neuromuscular, or musculoskeletal issues. She was independent in all ADLs and IADLs, ambulatory at community level without a device. The wound measures 18.5 cm × 12.7 cm × 3.8 cm deep, and connects to a smaller opening that is 3.6 cm × 1.7 cm.
Drainage is moderate, tends to have a slight green tinge, but no odor after thorough cleansing.
Lab values of note: Hb1AC is 6.1, albumin is 2.2, hemoglobin is 10.4.
Medications: Vitamins per gastric bypass protocol. Patient has just completed a course of antibiotics (Vancomycin).
Social history: Patient lives with two daughters who are in school.
Patient goals:
To have surgical closure of wound as soon as possible
To return to work as a teacher’s aide
DISCUSSION QUESTIONS: ▪ Is pulsed lavage with suction an appropriate intervention for this patient?
▪ If so, describe the equipment and parameters you would use for optimal treatment.
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