Which of the following is NOT a type of epidermal cooling?

The choice of ultrasound applied pre-laser pulse as not being a type of epidermal cooling is accurate because ultrasound does not primarily function to cool the epidermis. Instead, ultrasound is a technique used for various medical and therapeutic applications, including imaging and tissue treatment. While it can potentially have some effects on tissue, it does not serve the main purpose of cooling the epidermis directly before or during laser treatments.

In contrast, bulk gel, contact cooling devices, and air cooling concerns are directly related to cooling the skin. Bulk gels are applied topically to provide a cooling effect before the application of energy-based devices, helping to protect the skin. Contact cooling devices, like windows that circulate cooling liquids, are designed to keep the surface temperature of the skin low during treatments to minimize discomfort and protect against thermal injury. Similarly, air cooling systems, such as Zimmer coolers, utilize a blast of chilled air to lower the skin temperature and provide comfort during procedures.

Understanding the specific functions of these methods clarifies why ultrasound is not classified as an epidermal cooling technique, which focuses on methods actively utilized to manage skin temperature during laser and electrolysis treatments.