Identification of optimal control compartments for serial near-infrared spectroscopy assessment of lower extremity compartmental perfusion.

Near-infrared spectroscopy (NIRS) has shown promise in detecting ischemic changes in acute compartment syndrome. The objectives of this study were to 1) assess the correlation in NIRS values between upper and lower extremity control sites for bilateral lower extremity trauma and 2) investigate the effect of skin pigmentation on NIRS values. Forty-four volunteers (14 male, 30 female) were monitored over separate 1-hour sessions. NIRS leads were placed over leg and upper extremity compartments. Colorimeters were used to document skin pigmentation. NIRS values between corresponding contralateral compartments were extremely well correlated (r = 0.76-0.90). Upper extremity NIRS values were correlated to leg values in the following order: volar (r = 0.65-0.71), dorsal (r = 0.36-0.60), and deltoid (r = 0.42-0.51). A negative correlation was observed between melanin and NIRS values. Analogous leg compartments are the optimal site of control for each other. The volar forearm may be the best upper extremity control. Skin pigmentation may affect absolute NIRS values.