Crush Injury and Compartment Syndrome
Acute peripheral traumatic ischemia includes those injuries that are caused by trauma that leads to ischemia and edema; a gradient of injury exists. This category contains crush injuries as well as compartment syndrome.
Crush injuries often result in poor outcome because of the body’s attempt to manage the primary injury. The body then develops more injury due to the reperfusion response. Injuries are graded using definite points on a severity scale. The commonly referenced system is the Gustilo classification, but other classification scales are available.
The benefits of hyperbaric oxygen therapy (HBOT) for this indication include hyperoxygenation by increasing oxygen within the plasma. HBOT also induces a reduction in blood flow that allows capillaries to resorb extra fluid, resulting in decreased edema. As a gradient of oxygenation is based on blood flow, oxygen tissue tensions can be returned, allowing for the host defenses to properly function. Animal studies suggest that a decreased neutrophil adherence to ischemic venules is observed with elevated oxygen pressures (2.5 ATA). Reperfusion injury is diminished, as HBOT generates scavengers to destroy oxygen radicals.
Compartment syndrome also is a continuum of injury that occurs when compartment pressures exceed the capillary perfusion pressures. The extent to which the injury has affected tissues is unclear, even after surgical intervention. HBOT is not recommended during the “suspected” stage of injury, when compartment syndrome is not yet present but may be impending. HBOT is beneficial during the impending stage, when objective signs are noted (pain, weakness, pain with passive stretch, tense compartment). With these signs, even if surgery is not elected because of compartment pressures or patient stability, HBOT is indicated. Once the patient has undergone fasciotomy, HBOT can be used to help decrease morbidity.
Common Treatment Protocol
HBOT should be started as soon as is feasible, ideally within 4-6 hours from time of injury. After emergent surgical intervention, the patient should undergo HBOT at 2-2.5 ATA for 60-90 minutes. For the next 2-3 days, perform HBOT 3 times daily, then twice daily for 2-3 days, and then daily for the next 2-3 days.