Pathophysiology of Compartment Syndrome

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- Discussion:
    - occurs when pressure in a muscle compartment is > pressure in the capillaries,
            which leads to progressive muscle ischemia and edema and left untreated can
            result in infarction of the compartment contents;
    - ischemia and necrosis of the muscles occur even though the arterial pressure is
            still high enough to produce pulses;
    - muscle and nerves can survive for upto 4 hours of ischemia w/o irreversible damage;
            - nerve kept ischemic for under 4 hours will show neuropraxic damage,
                  whereas after 4 hours, nerves will show irreversible damage;
    - Whiteside' Theory:
            - the development of a compartment syndrome depends not only on intra-compartment
                  pressure but also depends on systemic blood pressure;
            - DBP - CP should be greater than 30

- Causes:
    - prolonged compression over a compartment (drug over dose)
        - Intramuscular pressures with limb compression clarification of the
                pathogenesis of the drug-induced muscle-compartment syndrome.
                Owen CA.   Mubarak SJ.   Hargens AR.   Rutherford L.   Garetto LP.
                Akeson WH.
                New England Journal of Medicine.   [JC:now]   300(21):1169-72, 1979 May 24.
                - measured intramuscular pressure by inserting wick catheters into 10 volar
                        forearms and 10 anterior tibial compartments of adult volunteers.
                - placed the subjects in positions in which victims of drug overdose are
                        commonly found. Intramuscular pressures in the area of direct
                        compression on hard surfaces ranged from 26 to 240 mm Hg, and averaged
                        101 mm Hg.
    - fractures (both open and closed)
    - improper casting of fractures
    - burns
    - infiltration of IV medications (chemotherapy)
    - intra compartment hemorrhage (direct arterial injury, Coumadin, Hemophilia)
    - tumors
    - improper positioning of the well leg on the frx table
          Compartment syndrome in the well leg resulting from fracture-table positioning.
          Anglen J.   Banovetz J.
          Clinical Orthopaedics & Related Research.   (301):239-42, 1994 Apr.