Wounds and Lymphedema
Patients with lymphedema have significantly increased risk of wound formation. This can occur due to infection, moisture buildup and fungal infection in skin folds, as well as trauma. Because the limb can become very swollen and under some tension, small nicks and scratches which might otherwise heal may become wounds. Furthermore, lymph fluid can drain from the wounds which can increase infection risk and slow healing. Therefore, good skin and wound care and compliance with compression are all important factors to reducing risk of developing further complications.
General Principles of Wound Care
- Keep the wound clean. Have your patient cleanse and irrigate the wound with sterile saline unless you instruct them otherwise. Clean tap water may be substituted if saline not available.
- Keep the wound covered with a clean or sterile dressing. Choose dressings to keep wound bed moist, but that can contain drainage appropriately.
- If your patient has swelling, try to keep the limb elevated when not ambulating. Reducing swelling can speed wound healing. See below for more information about the importance of reducing swelling for healing.
It is important to keep the wound bed clean. Irrigation of the wound with low pressure sterile saline can help dislodge bacteria and remove loose material. Irrigating the wound bed should be part of routine care. Systemic reviews have not shown higher infection rates using tap water than sterile saline for wound infections, but sterile saline is generally considered safer if available. Use of other agents such as iodine or antiseptic solutions are generally unnecessary for routine wound care and could potentially impede wound healing. Use of a syringe under pressure to give 8-15psi has been shown in some studies to help dislodge bacteria from the wound bed.
Wounds that have devitalized tissue on them benefit from debridement of the wound bed. Dead tissue on the wound bed can serve as a medium for bacterial growth. Dead tissue causes an inflammatory response which can impede the body’s attempt to heal and consumes some of the body’s resources for healing. It is widely accepted that wound debridement is necessary for optimal wound healing in many cases. If you are not as experienced with wound care, you may want to refer your patient to a to a wound care professional to discuss debridement options.
Wound debridement can be done by several methods, including autolytic, surgical / sharp, mechanical, enzymatic, and biological. If the wound bed is kept moist, the body will soften and remove dead tissue by itself, a process called autolytic debridement. Wound debridement can be done surgically and use of a scalpel is the most common method. Topical anesthesia can make this procedure less painful or even painless for your patient. Other types of debridement include enzymatic debridement preparations or biologic debridements such as maggot therapy.
Modern wound care has shown that wounds that are kept moist have the best healing. It is important, however, to match the dressing with the amount of wound drainage. Moderate and heavily draining wounds benefit from wound dressings that can wick moisture up and away from the wound bed. It is also important to protect the edges of the wound. If the wound is draining heavily, the periwound skin can become soaked with wound fluid and cause further wound breakdown, even in the absence of any infection or heavy bacterial colonization. Use of a periwound barrier that contains dimethicone or zinc is advisable for wounds with significant drainage.
Selection of the appropriate wound dressing and changing it accordingly can have a big impact on how fast a wound heals, as well as scarring. No single dressing is perfect for all wounds, and often the type of dressing will change several times as wound healing progresses. It is best to work with an experienced clinician on a case-by-case basis. Basic types of wound dressings include:
- Hydrogels – can contain up to 90% water. These dressings add moisture to wound beds.
- Hydrocolloids – This is a sheet dressing that provides a moist healing environment and protects the wound from bacteria.
- Foam dressings – these can protect wound bed and some are highly absorptive.
- Collagen dressings – these dressings contain collagen, the most abundant protein in the body. The dressings are indicated for clean wound beds with good granulation tissue. Collagen dressings can donate collagen to the wound bed and also work to attract cells to the area to speed the wound healing process.
- Silver dressings –Silver is antimicrobial and can help reduce bioburden in wound beds. There are several newer published studies, which suggest bacterial resistance to silver can occur.
- DACC – a newer technology, which binds bacteria to remove from the wound. One study shows DACC can bind over 100k bacteria / cm2 in just 30 seconds, and millions / cm2 within a few hours. DACC dressings can be combined with other dressings to help remove bacteria from the wound bed.
Why is it Important to Reduce Swelling?
- Swollen patients have lower oxygen delivery to the cells due to Fick’s law of diffusion. The oxygen released in the capillaries has to diffuse a greater distance through the interstitial fluid to get to the cells. This creates additional stress for the cells and increases infection risk.
- Compression helps by increasing hydrostatic pressure and helps force the fluid back in the bloodstream, reducing the edema. This restores oxygen and nutrient delivery to the cells.
- White blood cells require oxygen to fight infections. White blood cells use oxygen to create oxygen radicals that help fight infections. Superoxide Dismutase is the enzyme in the macrophage white blood cells that creates the oxidative burst that fights infection. If the oxygen tension is lower, white blood cells do not function as well, increasing infection risk and severity.
- Bacteria which enter the interstitial fluid planes can travel through the fluid planes and spread quickly. Reducing edema helps reduce infection severity. You can see below how the bacteria quickly travel and replicate in the interstitial space between the cells.
- The fluid found in the interstitial space of lymphedema patients has elevated protein content. These proteins can serve as nutrients for the bacteria to grow and spread more quickly. Also, the body uses Macrophages to process the lymph proteins in the interstitial fluid, which may reduce the body’s ability to fight the infection. This is why infections tend to be worse in lymphedema patients.