Intracompartmental Pressure Monitoring
PREREQUISITE NURSING KNOWLEDGE
• Nurses performing intracomparmental pressure monitoring (IPM) must have detailed knowledge of the anatomy of the involved limb compartments (Fig. 122-1), including external landmarks associated with each compartment. Compartment syndrome may also develop in the abdomen (abdominal compartment syndrome [ACS]). For directions on measurement of bladder pressure, refer to Procedure 106.
• All clinicians involved with performing and assisting with the procedure should have knowledge of aseptic technique.
• Nurses should be credentialed in performing IPM. This should include supervised training in the techniques used for IPM and opportunities to maintain clinical competence.
• Clinicians should have a high index of suspicion that the patient is at risk for developing compartment syndrome. Etiologies can be divided into internal and external sources. Examples of internal causes include fractures, contusions, and edema formation associated with crush injuries or reperfusion injuries. External sources are generally related to compression of the limb and include such things as eschar from burn injuries, splints, casts, dressings, and immobility.1 Definitive treatment may be as simple as releasing a splint, cast, or dressing. More advanced treatment may require release of the compartment with an escharotomy or fasciotomy.
• The pathophysiology of compartment syndrome is related to compromised perfusion. Blood flow to any tissue or organ requires a sufficient perfusion pressure, which is generally calculated as the mean arterial pressure minus the intracompartmental pressure and should be 70 to 80 mm Hg.2 Therefore, as the mean arterial pressure decreases or the intracompartmental pressure increases, the perfusion to the tissue is reduced. Insufficient perfusion pressure may lead to ischemia and eventual necrosis of the tissues within the affected area.
• Normal compartment pressure within an unaffected compartment is considered less than 10 mm Hg.3,4 Clinically significant pressure changes are generally defined in one of two ways:
An absolute value of more than 30 mm Hg in the presence of other signs and symptoms of compartment syndrome. However, injury of the area may lead to elevations of the intracompartmental pressure in the absence of actual compartment syndrome.5 Positioning of the extremity may also cause elevations in intracompartmental pressure particularly when assessing dependent compartments.
A delta compartment pressure (δp) of less than 30 mm Hg: the diastolic blood pressure minus the intracompartmental pressure. This measurement may be a more reliable indicator of the risk for development of compartment syndrome because it takes into account blood pressure.6,7
• Acute compartment syndrome is a true orthopedic emergency. Signs and symptoms can develop in as little as 2 hours after injury. Ischemic damage to muscles and nerves can start in 4 to 6 hours, with permanent damage occurring in 12 to 24 hours.3
