6 Ps and 3 As of Compartment Syndrome

Clinical features

A. Adolescents and Adults

Mnemonic: 6 Ps (by Hargens and Mubarak)

  1. Pain (may be absent in cases of nerve damage):
    • Pain out of proportion to other physical findings (requiring increasing analgesic requirement) *: Earliest symptom
    • Pain on passive stretch of the muscles in concerned compartment *
    • Low sensitivity and high specificity (large false-negative or missed cases)
  2. Pressure*: Tense and rigid swelling
    • Higher sensitivity and lower specificity compared to other signs
  3. Paresthesia and hypesthesia (late sign): In the territory of the nerves traversing the affected compartment
    • Low sensitivity and high specificity
  4. Paralysis (late sign):
    • Worst clinical sign or symptom
    • Poor prognostic indicator
  5. Pallor (late sign)
  6. Pulselessness (late and omnious sign)

*most important clinical signs and symptoms

4 PsSensitivity (%)Specificity (%)Positive predictive value (%)Negative predictive value (%)
Pain19971498
Paralysis13971198
Paresthesia13981598
Pressure (swelling)54767063
compartment syndrome mnemonic
6P and 3A of compartment syndrome

B. Young Children

Mnemonic: 3 As (by Noonan and Mcarthy)

  1. Anxiety
  2. Agitation
  3. Analgesia requirement increasing
    • Earlier and more sensitive indicator of Pediatric ACS than neurovascular changes or uncontrolled pain
    • May precede neurovascular changes by upto 7 hours

Note: Clinical features of compartment syndrome are more suggestive in their absence in ruling out the diagnosis than in confirming the diagnosis by their presence.


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