Pathophysiology compartment syndrome
Overview
Any condition that results in an increase in compartment contents or reduction in a compartment’s volume could lead to the development of an acute compartment syndrome. When pressure is elevated capillary blood flow is compromised. Edema of the soft tissue within the compartment further raises the intra-compartment pressure, which compromised venous and lymphatic drainage of the injured area. Pressure, if further increased in a reinforcing vicious cycle, can compromise arteriole perfusion, leading to further tissue ischemia.
The normal mean interstitial tissue pressure is 25 mmHg (range 20–30 mmHg), and if it is over 50–60 mmHg or below 10mmHg (or below the diastolic blood pressure minus 20–30 mmHg) functional tissue changes can occur e.g tissue necrosis. . Arteries and arterioles are stable at these pressures, however the tissues within the compartment dependent on the capillaries for nutrients suffer hypoxia.
Untreated compartment syndrome mediated ischemia of the muscles and nerves lead to eventual irreversible damage and death of the tissues within the compartment.
Pathophysiology
Compartment syndrome is defined as ‘an increased pressure within a confined compartmental space decreasing the perfusion pressure to the tissue. CS is caused by increasing pressure due to the edema and/or hemorrhage within an anatomic compartment bound. Increased pressures leads to the decreased capillary perfusion pressure resulting in sensory disturbance, pain at rest, ischemia, soft tissue compromise, and subsequent necrosis, and even ischemic neuropathy and chronic neuropathic pain. CS is defined as ‘an increased pressure within a confined compartmental space decreasing the perfusion pressure to the tissue. Whenever fluid (from bleeding etc) enters into a fixed volume compartment, both the tissue and venous pressure increase then the capillary collapse with ensuing muscle leading to the nerve ischaemia. A similar reduction in capillary perfusion pressure when the compartment size changes for example during the external compression, then due to an increase in intracompartmental pressure, as well as a reduction in the arteriolar pressure.
