Treatment & complications
A fasciotomy for ACS should be done less than ______ hours after injury to ensure the best outcome.
If done within 6 hours, recovery is usually 100%. After 6 hours the risk of permanent nerve damage increases.
What is the earliest and most common symptom of ACS
Severe pain (often out of proportion to the injury - such as a child who has severe pain after a cast is placed)
Fracture of this type of bone accounts for more than 75% of ACS cases
long bones
A limb with compartment syndrome will likely feel like this when palpated
Hard or "wood-like"
This factor determines the prognosis of ACS
The prognosis depends on the amount of time that has elapsed prior to performing the fasciotomy:
This type of fracture occurs when the bone is broken into 2 (or 3 depending on the source) different pieces.
comminuted
This compartment of the leg is the most susceptible to ACS
anterior
The normal pressure of a compartment is _______. Compartment syndrome is diagnosed if the pressure is at or above _______.
0-10 mm/Hg; 30 mm/Hg
What is the cause and consequence of systemic crush syndrome?
rhabdomyolysis -> hyperkalemia and myoglobinemia -> crush syndrome -> acute kidney injury, shock, worsening of ACS
This symptom caused Jesus Ortega to feel "like ants are crawling on my leg"
paresthesia - damage to peripheral nerves
This vascular structure is the first to become compressed because of already low pressure in its lumen.
Veins
The cause Ortega's serum lab values.
rhabdomyolysis - breakdown of skeletal muscle and the resulting secretion of CPK, K, Ca (eventually), and myoglobin
What is the purpose of "aggressive hydration" in ACS?
Hypotension reduces perfusion, exacerbating tissue injury, and should be treated with boluses of intravenous isotonic saline.
What are the "5 P's" of ACS?
pain, pallor, pulselessness, paresthesias, poikilothermia (cold skin temperature)
*in First Aid but disputed in Up To Date (just FYI)
Hypoxia develops because of compression of these structures.
Arterioles
Pain is usually increased in the compressed limb when the physician stretches or folds and holds it?
stretch -> anterior compartment syndrome of the leg will have increased pain with plantar flexion of foot or flexion of toes
What is done with the incision of a fasciotomy immediately after pressure is relieved?
Incision is left open for 2-3 days to allow for full resolution in the compartment before being closed.
Why is the urine of patients often dark with severe ACS?
increased myoglobin
What is the pathophysiology of compartment syndrome
external or internal compression -> increased compartment pressure -> obstruction of venous outflow and collapse of arterioles -> decreased tissue perfusion -> lower O2 supply to muscle -> necrosis 4-6 hours after ischemia
What tool is used to determine the amount of pressure in a compartment
Intra-compartmental pressure monitor