Direct measurement of tissue pressure in muscle compartments using a pressure monitor (e.g., Stryker Pressure Monitor introduced in 1988) may also be useful in determining if escharotomy and fasciotomy are needed (see Plate 7-15). However, use of invasive pressure monitoring increases the risk of infection of the muscle because the needle must traverse the invariably contaminated burn wound.

Evidence of vascular embarrassment mandates immediate escharotomy, which is performed at bedside using either a scalpel or electrocautery device. Anesthesia is not required because the incisions are made in an insensate third-degree burn. The escharotomy incision is placed in the midmedial or midlateral line of the involved limb and must extend from the distal margin to the proximal margin of the encircling eschar. The incision is carried through the eschar and the immediately adjacent superficial fascia only to the depth necessary to permit the cut edges of the eschar to separate. Bleeding, which is minimal in a properly performed escharotomy, is readily controlled with electrocautery or brief application of external pressure. The escharotomy incisions must be carried across involved joints, where there is the least amount of subcutaneous padding and the vessels and nerves are most easily compressed by the edema-generated pressure.

If a midlateral escharotomy does not restore circulation to a circumferentially burned limb, a second incision is placed in the midmedial line. If the circulation remains impaired after the second escharotomy, fasciotomy must be considered. Rarely, encircling burns of the neck require escharotomy in the line of the anterior margin of the sternocleidomastoid muscle and a circumferentially burned penis may require escharotomy in the middorsal line.

If edema formation beneath an encircling third-degree burn on the truck impairs the ventilatory excursion of the chest wall, mild hypoxia may develop and increased pressure may be needed to ventilate the patient. Bilateral escharotomy incisions extending from the clavicle to the costal margin should be made in the anterior axillary line. If the burn involves a significant portion of the anterior abdominal wall, the anterior axillary incisions should be connected by an incision at the costal margin. All escharotomy incisions must be protected by a generous application of a topical chemotherapeutic agent.