Dressings

Dressings are one of several interventions required to treat a wound. The appropriate choice of a dressing aids the body’s ability to heal a wound. Dressings are intended to keep the wound bed moist, remove excess exudate, provide a barrier against contamination, and to promote gas exchange. An appropriate dressing increases healing rate, reduces pain, and decreases infection rates while being cost effective and affordable (Broussard 2007). Due to the estimated costs associated with pressure injuries and their treatment, various dressings used with the SCI population have been investigated. There is little evidence that dressing protocols in pressure injuries in people with SCI are different than the general population (Houghton et al. 2013). The Registered Nurses Association of Ontario (2007), as cited by Houghton et al. (2013), recommends that the dressing selected:

• Keeps the ulcer bed continuously moist and the surrounding skin dry
• Controls exudate but does not dry out the wound bed or macerate the peri-wound
• Provides thermal insulation and wound temperature stability
• Protects the wound from microbial contamination
• Maintains its integrity and does not leave fibres or foreign substances in the wound
• Does not cause wound bed trauma on removal
• Meets the following criteria: simple handling, economical in cost and time, promotes (or does not slow) wound healing, acceptable to the person with the pressure injury

Although many dressing products are available, only three specific dressing materials (i.e., hydrocolloid, hydrogel, platelet gel and phenytoin) have some evidence for use in the SCI population.

When hydrocolloid dressings are placed over a wound, the dressing absorbs the exudate and changes into a gel. The outside of the dressing allows for gas exchange and protects against outside contamination. Hydrocolloid dressings maintain a moist wound environment and support autolytic debridement. Dressings can be left in place for 3-7 days, decreasing time and costs (Heynemen et al. 2008; Consortium for Spinal Cord Medicine 2000; Houghton & Campbell 2007; Houghton et al. 2013). Hydrocolloid dressings are typically used for stage II and III pressure injuries (Heynemen et al. 2008).

Hydrogel dressings act to retain moisture and rehydrate wounds, provide autolytic debridement and fill dead space. They provide minimal absorption of exudates. Hydrogel is available as a sheet or in an amorphous viscous form which requires a secondary dressing (Broussard 2007; Consortium for Spinal Cord Medicine 2000). Hydrogel dressings can be left in place for 48-72 hours depending on the type of hydrogel in use (Broussard 2007).

Platelet gels are rich in growth factors that are thought to aid wound healing and are stored in the frozen state until ready for use. It is commonly used in conjunction with a polyurethane sponge/semi-permeable film dressing system (Biatain Coloplast®).

Phenytoin is most commonly known as an oral anti-epileptic medication but the healing properties of topical phenytoin were first reported over 50 years ago. Over the years, various topical preparations of phenytoin have been studied and, while its exact mechanism of action is unknown, it is thought to enhance healing by stimulation of fibroblast proliferation, promotion of collagen deposition, antibacterial activity and decreased collagenase activity (Anstead et al. 1996; Kelin & Gorling 1961; Subbanna et al. 2007). It has not been widely used because its efficacy has not been sufficiently established through controlled clinical trials (Ovington 1999; Subbanna et al. 2007).

Discussion

In a RCT, Scevola et al. (2010) found healing was triggered earlier as indicated through onset time of granulation tissue proliferation when platelet gels were used to treat pressure injuries in individuals with SCI. Platelet gel use did not make a difference in wound volume reduction and was only effective within the first two weeks of treatment.

In a RCT involving 83 subjects, Hollisaz et al. (2004) found that those in the hydrocolloid dressing group (n=28) had the greatest completion of healing regardless of ulcer location and stage (74%; p<0.005), compared to those in the phenytoin cream group (40%; n=28) or simple dressing group (27%; n=27). For stage I ulcers, those in the hydrocolloid group healed faster than those in the other two groups; however, for stage II ulcers, there was no difference in healing between the hydrocolloid and phenytoin cream groups (67% vs 48%; p>0.05). In examining the area of injury, gluteal ulcers also healed more completely in the hydrocolloid group than in the other two, whereas the healing of sacral ulcers did not differ between the three groups.

Using a phenytoin solution (5mg/ml), Subbanna et al. (2007) found improvements in PUSH 3.0 and ulcer size when compared to normal saline but the differences did not reach statistical significance (p=0.261 and p=0.132, respectively).

Whittle et al. (1996) treated five pressure injuries (stage II-IV) with hydrogel dressings. After approximately 4-6 weeks of treatment, three ulcers healed completely while the two others showed a large improvement. Kaya et al. (2005) compared the effectiveness of applying an occlusive hydrogel type dressing to a poviodine-iodine soaked gauze dressing. There were no statistically significant differences in rate of healing but significantly more ulcers healed with the hydrogel dressing.

Conclusion

There is Level 1 evidence (from one randomized controlled trial; Hollisaz et al. 2004) that completion of healing for stage I and II pressure injuries is greater with an occlusive hydrocolloid dressing compared to phenytoin cream or simple dressing post-SCI.

There is Level 2 evidence (from one randomized controlled trial; Kaya et al. 2005) that occlusive hydrogel-type dressings heal more pressure injuries than conservative treatment post-SCI.

There is level 1 evidence (from one randomized controlled trial; Subbanna et al. 2007) that topical phenytoin shows a trend towards healing of stage I and II pressure injuries post SCI.

There is level 2 evidence (from one randomized controlled trial; Scevola et al. 2010) that platelet gel dressings when used within the first 2 weeks of treatment can trigger earlier granulation tissue proliferation toward pressure injury healing, post-SCI.