title: Reproducibility of different laser Doppler fluximetry parameters of postocclusive reactive hyperemia in human forearm skin.
abstract: BACKGROUND
  Postocclusive reactive hyperemia in forearm skin is a commonly used model for studying microvascular reactivity function, particularly in the assessment of vascular effect of topically applied pharmacological substances. In this study, we investigated the reproducibility of several different laser-Doppler-derived parameters in the measurement of postocclusive reactive hyperemia at forearm skin in healthy subjects.
  
  
  METHODS
  Eighteen young healthy male volunteers were recruited and studied in a supine position while fasted. Forearm blood flow was occluded at suprasystolic pressure for 3 min. Microvascular perfusion was measured continuously using laser Doppler fluximetry. Parameters studied were maximum increase in hyperemia perfusion (PORHmax), time-to-peak (Tp), amplitude of peak perfusion (PORHpeak), percentage of hyperemic response (PORH%) and mean velocity of the hyperemia increase (PORHmax/Tp). Measurement was performed twice within each study day for 2 study days. Coefficient of variation and intraclass correlation coefficient (ICC; with 95% confidence interval) were calculated for each parameter. An ICC value above 0.75 was interpreted as "excellent reproducibility".
  
  
  RESULTS
  ICC analysis showed that all studied parameters, except for PORH%, demonstrated excellent reproducibility for both within- and between-day measurements. Satisfactory intraday and interday coefficients of variation (<10%) were also obtained for these parameters.
  
  
  CONCLUSIONS
  Laser-Doppler-derived PORHmax, Tp, PORHpeak and PORHmax/Tp were highly reproducible parameters for measuring microvascular reactivity during reactive hyperemia, with PORHmax shown as the most reproducible index. PORH% is, however, less reproducible. These findings have implications for the use of laser Doppler fluximetry coupled with 3-min-occlusion PORHmax as a useful and reliable noninvasive clinical measurement index of microvascular function.
authors.affiliation: Department of Pharmacology, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia. yvonnetee623@hotmail.com
authors.forename: Get Bee
authors.initials: GB
authors.lastname: Yvonne-Tee
authors.forename: Aida Hanum Ghulam
authors.initials: AH
authors.lastname: Rasool
authors.forename: Ahmad Sukari
authors.initials: AS
authors.lastname: Halim
authors.forename: Abdul Rashid Abdul
authors.initials: AR
authors.lastname: Rahman
mesh_terms: D000328:Adult; D001916:Brachial Artery / Q000293:injuries / Q000503:physiopathology; D003627:Data Interpretation, Statistical; D005542:Forearm / Q000098:blood supply / Q000503:physiopathology*; D006801:Humans; D006940:Hyperemia / Q000209:etiology / Q000503:physiopathology*; D017078:Laser-Doppler Flowmetry / Q000009:adverse effects / Q000379:methods*; D008297:Male; D008833:Microcirculation / Q000503:physiopathology; D015203:Reproducibility of Results; D012867:Skin / Q000098:blood supply / Q000503:physiopathology*; D013997:Time Factors