Reproducibility of different laser Doppler fluximetry parameters of postocclusive reactive hyperemia in human forearm skin.
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.
Yvonne-Tee
Get Bee
GB
Department of Pharmacology, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia. yvonnetee623@hotmail.com
Rasool
Aida Hanum Ghulam
AH
Halim
Ahmad Sukari
AS
Rahman
Abdul Rashid Abdul
AR
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