Failure to treat acute compartment syndrome (ACS) early leads to significant morbidity. Current practice depends on using clinical signs and intracompartmental pressure (ICP) monitoring to diagnose the syndrome but there is still debate regarding their accuracy and interpretation.

Patients admitted with injuries at risk of ACS underwent intramuscular (IM) pH and ICP monitoring combined with regular clinical assessment. Fasciotomies were performed on those with clinical and/or pressure based evidence of ACS. All patients were subsequently assessed for evidence of a missed ACS at at 6 & 12 months.

Of the 62 patients, 51 completed the protocol and were included in the analysis. They were divided into 2 groups: those who had ACS, either initially (fasciotomies; 13), or diagnosed at follow up (no fasciotomies; 7), and those with no evidence of ACS (31).

The sensitivity and specificity for the worst values for each variable were calculated and receiver operator characteristic (ROC) curves generated. The area under the curve for pH was 0.92, 0.73 for absolute pressure and 0.59 for delta pressure. To achieve a sensitivity of 95%, an absolute pressure of >30mmHg was 30% specific, a delta pressure of <33mmHg was 27%, while IM pH of 6.38 was 80% specific.

This study highlights the issues concerning current diagnostic methods for ACS. By comparison, IM pH radically out performed both the highest ICP and the lowest delta pressure, identifying patients early and accurately.