Comparison of NIRS, serum biomarkers, and muscle damage in a porcine balloon compression model of acute compartment syndrome

BACKGROUND Near-infrared spectroscopy (NIRS) has been shown to aid in the diagnosis of extremity acute compartment syndrome (ACS), offering continuous real-time capability to monitor perfusion in extremities. Porcine models of ACS have been developed to attempt to aid in the understanding of the development of ACS and provide better methods of diagnosing ACS. The objective of the present study was to assess and correlate NIRS, tibial intracompartmental pressure (TICP), tibial intracompartmental perfusion pressure (TIPP), serum markers of inflammation and muscle injury in a balloon compression model of ACS. METHODS Six swine were used. Balloon catheters were inflated below the cranial tibial muscle. Systolic, diastolic, and mean arterial pressures; compartmental pressures; and oximetry were measured before, during, and after balloon inflation/deflation. Cranial tibial muscle was collected for muscle damage scoring. Serum creatine kinase, myoglobin, tumor necrosis factor , IL-1, and IL-6 were measured. Data analysis included comparing differences in TICP, NIRS, and TIPP measurements as well as creatine kinase, myoglobin, tumor necrosis factor , IL-1, and IL-6 levels between time points. Pearson correlations were calculated for muscle degeneration and edema and NIRS. RESULTS Increases in TICP and decreases in TIPP were found. Near-infrared spectroscopy detected significant changes in tissue oxygenation at all the same time points. Myoglobin significantly increased from 45.7 13.0 ng/mL (baseline) to 219.5 +/- 57.3-ng/mL (balloon deflation) and continued to increase over the duration of the study. Creatine kinase significantly increased 2 hours after balloon deflation. Cranial tibial muscle degeneration, necrosis, and edema scores were higher in the test than the control legs. CONCLUSIONS Near-infrared spectroscopy of the compartment provided a reliable, sensitive measure of both an increase and decrease in TICP and TIPP in this porcine balloon model of ACS. Creatine kinase and myoglobin significantly increased following balloon removal. Significant correlations between muscle degeneration, edema, hemorrhage, and NIRS were found.