The lowering of postischemic compartment pressures with mannitol

This investigation sought to evaluate systemic infusion of mannitol for nonoperative lowering of elevated compartment pressures. Nine anesthetized, intubated, mongrel dogs underwent 12–14 hr of ischemia to a hind limb with a pneumatic tourniquet. Twelve hours after tourniquet removal the dogs were reanesthetized and wick pressure catheters were introduced into the anterolateral compartent of the ischemic limb. Five dogs received intravenous normal saline at a rate of 100 cc/hr for 3 hr. Then a bolus of 25 g of 25% mannitol was given followed by a continuous infusion of 20% mannitol at 15 g/hr for 2 hr. Compartment pressures were recorded at 12 hr postischemia, after normal saline, and after mannitol. Four dogs received no treatment and served as controls. All dogs had elevated compartment pressures (43 ± 4.8 mm Hg) 12 hr postischemia. The pressures were only slightly higher following saline infusion (45 ± 7.3 mm Hg). After mannitol all pressures fell to zero. When mannitol was discontinued pressures rose slightly but never greater than 10 mm Hg. Although all dogs had neuropraxia from the tourniquet, none of the treated dogs developed gangrene or contracture. These data show that elevated postischemic compartment pressures can be lowered to normal levels with systemic infusion of mannitol. This technique, which has been used successfully in one patient, provides an alternative to operative fasciotomy and its inherent morbidity.