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Evidence‐based approaches

Rationale

NPWT can expedite wound healing by creating a moist wound healing environment, removing bacteria, reducing oedema, increasing blood flow and oxygen to the wound bed, and stimulating angiogenesis and granulation (Powers et al. [87], Schreiber [93]). The benefits of NPWT include management of exudate, reduction of wound odour, reduction in the number of dressing changes required and improvement in quality of life (Janssen et al. [54], Milne [73], Ubbink et al. [108]). NPWT can be applied to open wounds (healing by secondary intention) or closed incisional wounds (healing by primary intention) (Anghel and Kim [3]).

The degree of negative pressure applied is dependent on the wound aetiology and patient tolerance (Henderson et al. [46]). The suction unit (Figure 18.15) can be set on continuous or intermittent according to the therapy required (Apelqvist et al. [4]). Continuous therapy can be used:

for highly exuding wounds
over unstable structures to minimize movement and help to stabilize the wound bed, when used on flaps and grafts
for patients with a high risk of bleeding (Smith & Nephew [96]).

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Figure 18.15 Negative pressure wound therapy dressing and unit (example of standard equipment and application).

Intermittent therapy stimulates the development of granulation tissue and can improve the rate of healing (Milne [73]). It has proven to be cost‐efficient, safe and effective as a treatment modality for wound care (KCI [58]).

Indications

NPWT is indicated for:

chronic wounds, such as venous leg ulcers and pressure ulcers
diabetic and neuropathic ulcers
post‐operative and dehisced surgical wounds
partial‐thickness burns
skin flaps and grafts
traumatic wounds
explored fistulae (Milne [73], Smith & Nephew [96]).

Contraindications

NPWT is contraindicated in:

clotting disorders (risk of bleeding) and acute mild to moderate bleeding in the wound after injury or debridement
grossly contaminated wounds
exposed organs, vessels, nerves and anastomotic sites, which might be altered or damaged by NPWT
wounds with necrotic tissue, eschar or thick slough (these will require debridement prior to NPWT)
malignant wounds due to the potential to stimulate proliferation of malignant cells (with the exception of palliative care to improve quality of life)
untreated osteomyelitis
non‐enteric and unexplored fistulae (Apelqvist et al. [4], Henderson et al. [46], KCI [58]).

Precautions should be exercised:

when there is active bleeding in the wound
when there is difficult haemostasis
when the patient is taking anticoagulants
in cases of spinal cord injury
in vascular anastomoses
in wounds with sharp edges, such as bone fragments (Apelqvist et al. [4], Henderson et al. [46]).

The wound site must be carefully assessed to ensure that NPWT is indeed the appropriate treatment modality. If signs of infection or complications develop, the therapy should be discontinued (KCI [58]). See Figures 18.15 and 18.16 for examples of NWPT devices.