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

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.