title: In vivo measurements of regional hemoglobin oxygen saturation values and limb-to-arm ratios of near-infrared spectroscopy for tissue oxygenation monitoring of lower extremities in healthy subjects.
abstract: OBJECTIVE
  Near-infrared spectroscopy (NIRS) is a noninvasive technique that allows monitoring of regional hemoglobin oxygen saturation (rSO2) values and might have a role in the diagnosis of peripheral arterial disease. We assessed the reproducibility and inter-subject variability of rSO2 values and rSO2 limb-to-arm ratios (LARs) in lower extremities of healthy subjects.
  
  
  METHODS
  The rSO2 values and rSO2 LARs were calculated in eight healthy subjects without peripheral arterial disease. The rSO2 values were measured at rest at six fixed spots at each lower limb and a reference spot at each upper arm. NIRS provided the rSO2 values without involvement of any other processing technique. After measurements were completed, rSO2 LARs were calculated by dividing the rSO2 value of a lower extremity spot by the rSO2 value of the arm. Measurements were performed twice on 1 day and repeated on 4 different days.
  
  
  RESULTS
  Mean coefficients of variation of measurements of rSO2 values and rSO2 LARs at the same spot in the same subject were respectively less than 6% and 8% for every measurement spot over time. Coefficients of variation of measurements at the same spot between different subjects were less than 15% and 19% for every measurement spot respectively.
  
  
  CONCLUSIONS
  NIRS is an easily applicable, noninvasive tool for measurement of tissue oxygenation of lower extremities in healthy subjects. The reproducibility of rSO2 values and rSO2 LARs at the same measurement spot in the same subject is good.
authors.affiliation: Department of Vascular Surgery, St Antonius Hospital, Nieuwegein, the Netherlands.
authors.forename: Reinout Pe
authors.initials: RP
authors.lastname: Boezeman
authors.affiliation: Department of Research and Developments, St Antonius Hospital, Nieuwegein, the Netherlands.
authors.forename: Johannes C
authors.initials: JC
authors.lastname: Kelder
authors.affiliation: Department of Perfusion, St Antonius Hospital, Nieuwegein, the Netherlands.
authors.forename: Frans Gj
authors.initials: FG
authors.lastname: Waanders
authors.affiliation: Department of Vascular Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Frans L
authors.initials: FL
authors.lastname: Moll
authors.affiliation: Department of Vascular Surgery, St Antonius Hospital, Nieuwegein, the Netherlands.
authors.forename: Jean-Paul Pm
authors.initials: JP
authors.lastname: de Vries
keywords: NIRS; lower extremities; rSO2; tissue oxygenation