Intramuscular pressure in the burned arm: measurement and response to escharotomy.

Using a wick catheter technique, sequential measurements of intramuscular pressure were obtained in 31 burned arms in 18 patients. Abnormally high pressures were recorded in 90 percent of extremities and exceeded the potentially harmful level of 30 mm Hg in 42 percent. Correlation of intramuscular pressure with signs and symptoms of extremity compression, including Doppler pulses, was poor. Intramuscular pressure elevation appeared to parallel edema formation beneath the burn wound. A high incidence of pressure measurements in excess of 30 mm Hg was found in patients who had 30 percent or greater total body surface area injury (67 percent), 10 percent or greater full-thickness burns (75 percent), and extremities with circumferential involvement (57 percent). In every case echarotomy produced a dramatic decrease in intramuscular pressure, while a randomized group of extremities that were not decompressed developed sustained pressures as high as 64 mm Hg despite the presence of intact Doppler pulses. Extremities treated in this manner appeared slower in resolving edema and regaining motion and strength. Measurement of intramuscular pressure beneath the burn eschar is recommended in evaluating all patients at risk from extremity burns.