Continuous monitoring flags acute compartment syndrome
medwireNews: Continuous intracompartmental pressure monitoring is highly accurate for the detection of acute compartment syndrome (ACS) after tibial diaphyseal fracture, say UK researchers who believe it may allow diagnosis before signs and symptoms occur.
Their review of medical records for 850 patients who underwent immediate monitoring on admission to the hospital over 10 years estimates the technique to be 94% sensitive and 98% specific for the diagnosis, with corresponding positive and negative predictive values of 93% and 99%.
"With the currently available evidence, the clinical diagnosis of acute compartment syndrome should no longer be considered the gold standard and we believe that all patients with tibial fractures who are at risk for [ACS] should undergo continuous intracompartmental pressure monitoring," say Andrew Duckworth and co-workers, from the Royal Infirmary of Edinburgh, UK.
Overall, 152 (17.9%) patients were diagnosed with ACS on the basis of a differential pressure below 30 mmHg for more than 2 hours, and subsequently underwent fasciotomy.
ACS, defined as the escape of muscles at fasciotomy and/or muscular color change or necrosis, was confirmed in 141 of these patients. Six patients' fasciotomy wounds were closed within 48 hours of surgery, and these patients were considered to have a false-positive diagnosis of ACS.
ACS was ruled out on the basis of monitoring in 698 (82.1%) patients. A true-negative diagnosis was confirmed in 689 of these patients by the absence of neurologic abnormality or contracture over an average of 59 weeks of follow up. Four patients had a false-negative diagnosis and later developed late ACS sequelae.
Finally, five patients underwent fasciotomy despite normal differential pressure readings following the development of clinical signs of ACS; diagnosis was confirmed in these false-negative cases.
Discussing their findings in theJournal of Bone and Joint Surgery, Duckworth et al say the diagnosis of ACS should only be made after at least 2 hours of monitoring shows no indication that pressure will rise above 30 mmHg.
"For this reason, surgeons should not depend on single measurements as this method is likely to lead to overtreatment," they emphasize.
The team adds: "Although this study was limited to tibial diaphyseal fractures, we believe that in the absence of evidence to the contrary, it is reasonable to use this protocol for other fractures and soft-tissue injuries. It may be less accurate in adolescents who may have low diastolic pressures; in these patients, it might be preferable to use the mean arterial pressure as the reference point."
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By Lynda Williams, Senior medwireNews Reporter