title: Monitoring for compartmental syndrome using near-infrared spectroscopy: a noninvasive, continuous, transcutaneous monitoring technique.
abstract: BACKGROUND
  The diagnosis of compartmental syndrome (CS) may be delayed because current monitoring techniques are invasive and intermittent and the compartment pressure (CP) that predicts ischemia is variable. Fiber-optic devices using near-infrared (NIR) wavelength reflection can determine the redox state of light-absorbing molecules and have been used to monitor venous hemoglobin saturation to detect ischemia during low-flow states. The purpose of this study was to determine if NIR spectroscopy can provide continuous, transcutaneous, noninvasive monitoring for muscle ischemia in an animal model of CS.
  
  
  METHODS
  Nine swine were anesthetized and a 20-mm NIR probe was placed over the anterolateral compartment of the hind leg to provide continuous determination of muscle oxyhemoglobin level. Needles were inserted into the compartment to measure CP. A nerve stimulator was placed over the peroneal nerve to induce dorsiflexion twitch. Albumin was infused into the muscle to incrementally increase CP until there was complete loss of dorsiflexion, then after 20 minutes fasciotomy was performed.
  
  
  RESULTS
  All animals lost dorsiflexion at CP of 43+/-14 mm Hg. There was a significant inverse correlation between CP and oxyhemoglobin level (r = -0.78; p < 0.001) and a correlation between oxyhemoglobin and perfusion pressure (mean arterial pressure minus CP) (r = 0.66; p < 0.001). Redox state was a more consistent predictor of twitch loss than perfusion pressure.
  
  
  CONCLUSIONS
  Muscle oxyhemoglobin level measured by NIR spectroscopy strongly reflected CP, perfusion pressure, and loss of dorsiflexion twitch. Currently available portable NIR devices may provide the benefit of continuous, noninvasive monitoring for CS. Further studies to determine the role of this technology in the detection of compartmental syndrome are warranted.
authors.affiliation: Department of Orthopedics, University of Washington School of Medicine, Seattle, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Garr
authors.forename: L M
authors.initials: LM
authors.lastname: Gentilello
authors.forename: P A
authors.initials: PA
authors.lastname: Cole
authors.forename: C N
authors.initials: CN
authors.lastname: Mock
authors.forename: F A
authors.initials: FA
authors.lastname: Matsen
mesh_terms: D000818:Animals; D001785:Blood Gas Monitoring, Transcutaneous; D003161:Compartment Syndromes / Q000175:diagnosis* / Q000378:metabolism; D004195:Disease Models, Animal; D008991:Monitoring, Physiologic / Q000379:methods; D009132:Muscles / Q000098:blood supply; D010108:Oxyhemoglobins / Q000378:metabolism; D019265:Spectroscopy, Near-Infrared; D013552:Swine
chemical_list: D010108:Oxyhemoglobins