Combined ultrasonic and enzymatic debridement of necrotic eschars in an animal model.

Several methods are used to debride burn eschars, however, most are ineffective for ischemic eschars. We investigated a novel combination of enzymatic and ultrasonic debridement for ischemic eschars. A previously described ischemic flap model in rats was used to compare the time to flap debridement or perforation of enzymatic (Debrase, a derivative of bromelain), ultrasonic, or combined debridement (Hybrid Debridement Technology). We also evaluated the effects of ultrasonic intensity, probe size, probe housing, and operation mode (pulsatile vs. continuous) on the time to full eschar perforation. Ultrasonic and enzymatic debridement alone did not result in flap perforation even after 15 minutes. Combined ultrasonic and enzymatic debridement resulted in flap perforation within 2 to 5 minutes in the four flap zones (P < 0.001 for all four flap zones compared with ultrasound alone). The most rapid debridement was observed with an ultrasonic intensity of 3.2 W/cm, applied using a 4.9 cm probe. The temperature elevation associated with ultrasonication was controlled by perfusion of fresh Debrase solution and alternating the ultrasound energy. Combination of ultrasonic and enzymatic debridement of ischemic flap eschars in rats with Debrase is more rapid and effective than either method alone.