The 5 P's · Circulation Assessment Acronym

The 5 P's of circulation assessment includes pain, pallor, pulse, paresthesia, and paralysis. 

Pain is assessed on a standardized scale typically from 0 to 10, with 10 being the worst pain ever experienced. Under typical conditions, pain should primarily be localized to the injury site and not be out of proportion to the severity of the injury. 

Pallor refers to the skin tone of the affected limb. Any deviation from the individual’s typical skin tone, especially blue or purple in color, can be indicative of compromised blood flow. A comparison should be made with the unaffected limb. Capillary refill time refers to the time it takes for blood to reperfuse to a body part after pressure. 

Pulse, specifically the radial, dorsalis pedis, and posterior tibial pulses, are checked to ensure proper blood flow. Depending on the source, pulses are rated on a scale of 0 to 4+, with 0 indicating no pulse and 4+ indicating a bounding pulse (i.e., strong pulsation that does not disappear with moderate pressure). A grade of 3 is considered an expected finding. 

Paresthesia refers to the sensation of numbness and tingling, which can be indicative of neurological trauma. Additionally, individuals may report diminished sensitivity to touch or feeling “pins and needles” on the affected limb. 

Lastly, paralysis refers to the inability to move the affected limb. 

Compartment syndrome is a painful condition where bleeding and swelling within a limb limits blood flow and oxygen and nutrients to the muscles and nerves. This occurs due to impairment of the fascia’s ability to expand and stretch. Acute compartment syndrome is commonly due to trauma, such as a motor vehicle accident or a crush injury. Compartment syndrome of the leg is widely due to tibial shaft fracture, which requires significant force, such as from a motor vehicle accident. This is in contrast to chronic compartment syndrome, which is associated with overexertion during exercise. Severe pain is typically the first indicator of compartment syndrome. The compromised extremity may become tense and edematous due to blood accumulation, increasing the pressure on nerve fibers. This results in pain that may feel disproportionate to the visible injury. Pallor and pulselessness occur due to compromise of arterial perfusion as the limb swells, and bloody supply is occluded. Notably, it can be expected for arterial pulses and regular capillary refill to persist even in the presence of prolonged and severe compartment syndrome. 

Paresthesia and complete paralysis may occur in the later stages of compartment syndrome. If the pressure in the compartment continues to increase, neuronal tissue can become ischemic, resulting in nerve dysfunction and paresthesia. In addition to feeling “pins and needles," the individual may report loss of light touch sensation, which may be assessed with a two-point discrimination test or pinprick testing. If tissue ischemia persists for more than four hours, motor function may deteriorate, resulting in paralysis of the affected limb. These functional losses may be irreversible after eight to 24 hours of tissue ischemia. In addition to feeling “pins and needles," the individual may report loss of light touch sensation, which may be assessed with a two-point discrimination test or pinprick testing. 

The 5 P's acronym is used systematically in a neurovascular assessment to assess compartment syndrome's presence. The P's refer to pain, pallor, pulse, paresthesia, and paralysis. Pain is commonly rated on a 10-point scale and can be disproportionately severe in the case of compartment syndrome. Pallor refers to the appearance of the skin and whether it appears as though blood is appropriately reaching the affected body part. Signs of poor perfusion include blue or purple discoloration that only affects the compromised limb(s).