Good bandaging requires touch as well as science

Effectiveness depends on consistency, skill

The effectiveness and safety of any compression bandage used to address the underlying causes of venous ulcers depends on proper wrapping technique. If the bandage is wrapped too loosely, it won't provide enough tension and may slip. If it is wrapped too tightly, it can cause discomfort, tissue damage, and necrosis.

Unfortunately, determining the optimum bandage tightness is extremely difficult, and knowing exactly how much compression a given patient needs is virtually impossible, according to Morris Kerstein, MD, professor of surgery at Allegheny University of the Health Sciences in Philadelphia.

"Let's say I have a patient with a venous ulcer who needs leg compression. I have no way to measure how much pressure he or she needs at the ankle," Kerstein says. "I can make some general assumptions based on an individual case, but I can never be absolutely certain. One of the complexities of compression therapy is that the better compression you have, the harder it is to get the device on or off," Kerstein says. The field of venous ulcers deserves far more thought and attention than it has been getting, and at the crux should be a focus on determining the degree of compression to use for each patient, he adds.

Compression therapy, it seems, is as much guesswork and good judgment as it is empirical medicine and time-tested techniques. Here are a few tips from experts on wrapping legs with compression bandages:

· Watch your stretch and overlap.

The amount of stretch and overlap of elastic layers has a direct effect on the resultant compression. More stretch and greater overlap translate into higher pressures. Too much pressure can result in a tourniquet effect; too little will not provide adequate compression and may lead to slippage of the bandage. Most wraps and bandage systems are designed to work optimally at 50% stretch and 50% overlap.

· Use guidelines to determine a 50% stretch.

Assessing a 50% stretch can be quite subjective, but there are a few guidelines. To achieve 50% stretch, pull the bandage to its full extension, then relax it approximately halfway. Apply the wrap consistently as you move upward from the ankle. This method assures that the pressure will be highest at the ankle and lowest as you move up toward the knee. Altering the degree of stretch at different points on the lower leg will result in inconsistent pressure gradients.

Some elastic bandages are marked with geometric patterns, such as squares or rectangles, that match up when the bandage is stretched to 50% but distort when stretched too far. Such visual aids may help to maintain consistency between bandagers, all of whom will doubtless display variations in their wrapping techniques.

· Ensure overlap is consistent.

Judging 50% overlap is somewhat easier. Again, bandagers should strive for consistent overlap throughout the bandaging process. Some bandages are made with visible midlines to make the estimation easier.

· Watch your elevation.

Don't forget about leg elevation. The effects of compression on swelling are enhanced by elevating the affected leg above the level of the heart when a patient is sitting or lying down.

· Apply padding around bony prominences.

While 50% stretch and 50% overlap will result in uniform average tension around the leg, in practice there may be significant variations in point-to-point pressure because the limb is shaped so irregularly. Bony prominences are bound to cause unintended pressure variances. To counteract these intermittent pressures, apply strips of adequate padding around or alongside bony protruding areas before wrapping the bandage.

· Don't let them slip.

Prevent bandages from slipping by following proper application techniques. Slippage will result in localized areas of high and low compression pressures.

· Always assess arterial status of patients. (See related story, p. 78.)