Therapeutic ultrasound is one of the most common treatments used in the management of soft tissue lesions, which constitute the majority of rheumatic complaints. Therapeutic ultrasound consists of inaudible high-frequency mechanical vibrations created when a generator produces electrical energy that is converted to acoustic energy through mechanical deformation of a piezoelectric crystal within the transducer. The waves produced are transmitted by propagation through molecular collision and vibration, with a progressive loss of intensity of the energy during the passage through the tissue, due to absorption, dispersion, or scattering of the wave. The total amount of energy in an ultrasound beam is its power, expressed in watts. The amount of energy that reaches a specific site is dependent upon characteristics of the ultrasound (frequency, intensity, amplitude, focus and beam uniformity) and the tissues through which it travels. Ultrasound equipment requires a conductive gel or lotion for clear ultrasonic transmission. What do practitioners look for in ultrasound gels and lotions?

When formulating ultrasound gels and lotions, the needs of diagnostic imaging should be kept in mind. The formulation should provide superior transmission for low-, medium-, or high-intensity sound waves that are acoustically correct for a broad range of frequencies.

Gels

Ultrasound gels with medium or high viscosities are excellent conductive agents for use in therapeutic ultrasound, diagnostic imaging, and other external procedures requiring a thick medium. The gel should have excellent lubricating and glide properties so that it will spread evenly without running or drying. It is also helpful if the gel is hypoallergenic, bacteriostatic, non-sensitizing, and will not irritate the skin, stain clothing, or damage transducers. The gel should also be long-lasting with no need to reapply often and should hold its form if heated up. Having no formaldehyde and being completely aqueous are other factors that chiropractors look for in ultrasound gels. A runny gel that does not hold its form very well can be messy and difficult to work with, because it will not spread evenly and will often give inaccurate readings.

Gels that are enriched with an aloe can be beneficial as they are often smoother with a better glide. The aloe is also beneficial for the skin, because it has shown to inhibit inflammation without side effects and support proper joint and muscle mobility.

Lotions

Ultrasound lotions are another option for chiropractors looking for a different conductive agent than gels. Lotions offer some advantages over gels in that they can be rubbed into the patient's skin after the treatment, which reduces the cleanup time and can minimize a patient's discomfort while he enjoys the rich texture and pleasant smell. Ultrasound lotions are often enriched with an aloe or offer a warming element with capsaicin, menthol, or both.

An ultrasound lotion enriched with menthol and capsaicin is a true therapeutic ultrasound lotion, because it will not only provide the conductivity, but it will also give some pain relief to the patients as the capsaicin will suppress the nerve endings that transfer the pain signals to the brain. Ultrasound lotions are often a bit more expensive than gels, but they provide an added benefit to the patient and can give more value to the overall treatment.

Avoiding Contamination

Concern has grown over cross-patient contamination of multi-use ultrasound gel bottles from repeated contact with environmental air, patient skin, and body fluids. Chiropractors and physical therapists seem quite aware of cross-contamination and are working to ensure patients' safety on these issues.

Refilling already-used bottles can compromise patient safety by mixing new gel with possibly contaminated gel still present in the bottle. Using single-unit-dose ultrasound scanning gel is one method to control cross-contamination. But these single-dose gels are hard to find and are fairly expensive. Because most practices prefer to buy ultrasound gels and lotions in large volumes—usually gallons or 5-liter containers—the single-dose packets are not very economical.

Ultrasound gels should have excellent lubricating and glide properties so that they will spread evenly without running or drying. Ultrasound lotions offer some advantages over gels in that they can be rubbed into the patient's skin after the treatment.

Cross-contamination is certainly easy to handle and to avoid for chiropractic practices. Simply treat the gel bottle like you would treat eye drops—do not touch the tip to anything, and do not let it sit around opened on the shelf forever! Probably one of the easiest ways to control cross-contamination is to simply wipe the probes or applicator units with a clean, dry, non-sterile paper towel between procedures, including probes and applicators used on contaminated scanning fields, open wounds, and cutaneous infections.

After the final procedure of the day, probes or applicators should be cleaned with a liquid cleaning solution to remove all traces of coupling gel or lotion, which could support the overnight growth of bacteria. This method would be cost-effective and time-efficient protocol for controlling infection and cross-contamination. Probe and applicator cover kits are also available that will prevent contamination and protect the expensive ultrasound probes and applicators.

Gel warmers are another piece of equipment used in practices in which cross-contamination should be addressed. To keep warmers and gels free from bacteria, warm gel should only be used when required. Bottles should be removed from the warmer as soon as possible and dried immediately. Gel warmers must be cleaned weekly with low-level, hospital-approved disinfectant, and immediately if the warmer becomes soiled.

Ultrasound gels and lotions must be stored in areas that are dry and protected from potential sources of contamination, such as dust, moisture, insects, and rodents. If evidence of contamination is present or package integrity has been breached, the product must be discarded and products should be rotated when restocking takes place. When Sombra decided to look into formulating ultrasound gels and lotions, we brought several local chiropractors into our place of business to get direct feedback on what they look for in ultrasound gels and lotions. At the Florida Chiropractic Association's National Convention in August, I also asked attending DCs what they looked for in ultrasound gels and lotions. The responses all had a common thread:

1. Price;
2. Availability;
3. Optional sizes;
4. Thickness of ultrasound gel and how well it holds its form if warmed up;
5. A gel enriched with aloe;
6. Lotions enriched with a warming element such as capsaicin; and
7. Can other needs of the practice be ordered at the same time as the ultrasound?

In a lot of practices, chiropractors do not concern themselves too much with ultrasound gels and lotions, so they leave it up to the assistants to order these supplies. Now, of course, if the performance of the gel or lotion is questioned by the DC, then alternatives will be looked into and the practice will have to start over to find a well-performing ultrasound gel or lotion where the rest of their supplies can also be ordered.

Jeff Baskett is program marketing manager for Sombra Professional Therapy Products. Contact him at .