SCIENTIFIC ARTICLE Ability of Near Infrared Spectroscopy to Measure Oxygenation in Isolated Upper Extremity Muscle Compartments Ashley L. Cole, MPH, Richard A. Herman Jr, BS, Jonathan B. Heimlich, BS, Sahir Ahsan, BS, Brett A. Freedman, MD, Michael S. Shuler, MD Purpose Near infrared spectroscopy (NIRS), a noninvasive means for monitoring muscle oxygenation, may be useful in the diagnosis of acute compartment syndrome, a condition characterized by poor tissue perfusion. This study used the decrease in muscle oxygen- ation caused by exercise to investigate the ability of anatomic placement of NIRS sensor pads over compartments of the forearm to isolate perfusion values of a specific com- partment. Methods We recruited 63 uninjured volunteers from a private clinic-based setting and placed NIRS sensor pads over the dorsal, volar, and mobile wad compartments of 1 forearm. A total of 49 participants also had the contralateral forearm monitored, which served as an internal control. Participants performed a series of 3 exercises designed to sequentially activate the muscles of each compartment. A washout period separated each exercise to allow perfusion to return to baseline. We compared NIRS values of each compartment recorded during muscle contraction with baseline values. Results Mean NIRS values decreased significantly from baseline during muscle contraction for all compartments, whereas mean NIRS values of muscle compartments that remained at rest showed little or no change. We observed no changes in NIRS values of the contralateral arm, which remained at rest during the entire data collection period. Conclusions Although lack of an existing method for quantifying muscle perfusion precludes validation of this technique against a reference standard, this study suggests that NIRS can provide oxygenation values that are both sensitive and specific to muscle compartments of the forearm. Future studies should investigate NIRS among patients with upper extremity injuries. (J Hand Surg 2012;37A:297 –302. Copyright © 2012 by the American Society for Surgery of the Hand. All rights reserved.) Type of study/level of evidence Diagnostic III. Key words Acute compartment syndrome, compartment syndrome, muscle perfusion, near infrared spectroscopy. From the Department of Upper Extremity and Micro Surgery, Athens Orthopedic Clinic, PA; J&M Shuler, Athens; the Medical College of Georgia, Georgia Health Sciences University, Augusta, GA; and the Land- stuhl Regional Medical Center, Landstuhl, Germany. Received for publication April 29, 2011; accepted in revised form October 19, 2011. Somanetics Corporation supplied INVOS devices used in this study. M.S.S. has pending intellectual property rights and a license agreement with the manufacturer. Corresponding author: Michael Shuler, MD, Department of Upper Extremity and Micro Surgery, Athens Orthopedic Clinic, PA, 1765 Old West Broad Street, Building 2, Suite 200, Athens, GA 30606; e-mail: msimmss@hotmail.com. 0363-5023/12/37A02-0014$36.00/0 doi:10.1016/j.jhsa.2011.10.037 ©  ASSH  Published by Elsevier, Inc. All rights reserved.  297